staging: Add dgrp driver for Digi Realport devices

This is based on dgrp-1.9 available from
ftp://ftp1.digi.com/support/beta/linux/dgrp/dgrp-1.9.tgz

Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

16 files changed, 10880 insertions, 0 deletions

diff --git a/drivers/staging/dgrp/Kconfig b/drivers/staging/dgrp/Kconfig
new file mode 100644
index 000000000000..39f4bb65ec83
--- /dev/null
+++ b/drivers/staging/dgrp/Kconfig
@@ -0,0 +1,9 @@
+config DGRP
+       tristate "Digi Realport driver"
+       default n
+       depends on SYSFS
+       ---help---
+       Support for Digi Realport devices.  These devices allow you to
+       access remote serial ports as if they are local tty devices.  This
+       will build the kernel driver, you will still need the userspace
+       component to make your Realport device work.
diff --git a/drivers/staging/dgrp/Makefile b/drivers/staging/dgrp/Makefile
new file mode 100644
index 000000000000..d9c3b88d7162
--- /dev/null
+++ b/drivers/staging/dgrp/Makefile
@@ -0,0 +1,12 @@
+obj-$(CONFIG_DGRP) += dgrp.o
+
+dgrp-y := 			\
+	dgrp_common.o 		\
+	dgrp_dpa_ops.o 		\
+	dgrp_driver.o 		\
+	dgrp_mon_ops.o 	 	\
+	dgrp_net_ops.o 		\
+	dgrp_ports_ops.o 	\
+	dgrp_specproc.o 	\
+	dgrp_tty.o 		\
+	dgrp_sysfs.o
diff --git a/drivers/staging/dgrp/README b/drivers/staging/dgrp/README
new file mode 100644
index 000000000000..1d8aaee270e8
--- /dev/null
+++ b/drivers/staging/dgrp/README
@@ -0,0 +1,2 @@
+The user space code to work with this driver is located at
+https://github.com/wfp5p/dgrp-utils
diff --git a/drivers/staging/dgrp/TODO b/drivers/staging/dgrp/TODO
new file mode 100644
index 000000000000..63341ade90d4
--- /dev/null
+++ b/drivers/staging/dgrp/TODO
@@ -0,0 +1,7 @@
+- Use configfs for config stuff.  This will require changes to the
+  user space code.
+
+- Check the calls to tty_register_device.  In particular, check to see
+  if there should be some handling for IS_ERR(classp).
+
+- dgrp_send() and dgrp_receive() could use some refactoring
diff --git a/drivers/staging/dgrp/dgrp_common.c b/drivers/staging/dgrp/dgrp_common.c
new file mode 100644
index 000000000000..fce74e7fb834
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_common.c
@@ -0,0 +1,200 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_common.c
+ *
+ *  Description:
+ *
+ *     Definitions of global variables and functions which are either
+ *     shared by the tty, mon, and net drivers; or which cross them
+ *     functionally (like the poller).
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/tty.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+
+#include "dgrp_common.h"
+
+/**
+ * dgrp_carrier -- check for carrier change state and act
+ * @ch: struct ch_struct *
+ */
+void dgrp_carrier(struct ch_struct *ch)
+{
+	struct nd_struct *nd;
+
+	int virt_carrier = 0;
+	int phys_carrier = 0;
+
+	/* fix case when the tty has already closed. */
+
+	if (!ch)
+		return;
+	nd  = ch->ch_nd;
+	if (!nd)
+		return;
+
+	/*
+	 *  If we are currently waiting to determine the status of the port,
+	 *  we don't yet know the state of the modem lines.  As a result,
+	 *  we ignore state changes when we are waiting for the modem lines
+	 *  to be established.  We know, as a result of code in dgrp_net_ops,
+	 *  that we will be called again immediately following the reception
+	 *  of the status message with the true modem status flags in it.
+	 */
+	if (ch->ch_expect & RR_STATUS)
+		return;
+
+	/*
+	 * If CH_HANGUP is set, we gotta keep trying to get all the processes
+	 * that have the port open to close the port.
+	 * So lets just keep sending a hangup every time we get here.
+	 */
+	if ((ch->ch_flag & CH_HANGUP) &&
+	    (ch->ch_tun.un_open_count > 0))
+		tty_hangup(ch->ch_tun.un_tty);
+
+	/*
+	 *  Compute the effective state of both the physical and virtual
+	 *  senses of carrier.
+	 */
+
+	if (ch->ch_s_mlast & DM_CD)
+		phys_carrier = 1;
+
+	if ((ch->ch_s_mlast & DM_CD) ||
+	    (ch->ch_digi.digi_flags & DIGI_FORCEDCD) ||
+	    (ch->ch_flag & CH_CLOCAL))
+		virt_carrier = 1;
+
+	/*
+	 *  Test for a VIRTUAL carrier transition to HIGH.
+	 *
+	 *  The CH_HANGUP condition is intended to prevent any action
+	 *  except for close.  As a result, we ignore positive carrier
+	 *  transitions during CH_HANGUP.
+	 */
+	if (((ch->ch_flag & CH_HANGUP)  == 0) &&
+	    ((ch->ch_flag & CH_VIRT_CD) == 0) &&
+	    (virt_carrier == 1)) {
+		/*
+		 * When carrier rises, wake any threads waiting
+		 * for carrier in the open routine.
+		 */
+		nd->nd_tx_work = 1;
+
+		if (waitqueue_active(&ch->ch_flag_wait))
+			wake_up_interruptible(&ch->ch_flag_wait);
+	}
+
+	/*
+	 *  Test for a PHYSICAL transition to low, so long as we aren't
+	 *  currently ignoring physical transitions (which is what "virtual
+	 *  carrier" indicates).
+	 *
+	 *  The transition of the virtual carrier to low really doesn't
+	 *  matter... it really only means "ignore carrier state", not
+	 *  "make pretend that carrier is there".
+	 */
+	if ((virt_carrier == 0) &&
+	    ((ch->ch_flag & CH_PHYS_CD) != 0) &&
+	    (phys_carrier == 0)) {
+		/*
+		 * When carrier drops:
+		 *
+		 *   Do a Hard Hangup if that is called for.
+		 *
+		 *   Drop carrier on all open units.
+		 *
+		 *   Flush queues, waking up any task waiting in the
+		 *   line discipline.
+		 *
+		 *   Send a hangup to the control terminal.
+		 *
+		 *   Enable all select calls.
+		 */
+
+		nd->nd_tx_work = 1;
+
+		ch->ch_flag &= ~(CH_LOW | CH_EMPTY | CH_DRAIN | CH_INPUT);
+
+		if (waitqueue_active(&ch->ch_flag_wait))
+			wake_up_interruptible(&ch->ch_flag_wait);
+
+		if (ch->ch_tun.un_open_count > 0)
+			tty_hangup(ch->ch_tun.un_tty);
+
+		if (ch->ch_pun.un_open_count > 0)
+			tty_hangup(ch->ch_pun.un_tty);
+	}
+
+	/*
+	 *  Make sure that our cached values reflect the current reality.
+	 */
+	if (virt_carrier == 1)
+		ch->ch_flag |= CH_VIRT_CD;
+	else
+		ch->ch_flag &= ~CH_VIRT_CD;
+
+	if (phys_carrier == 1)
+		ch->ch_flag |= CH_PHYS_CD;
+	else
+		ch->ch_flag &= ~CH_PHYS_CD;
+
+}
+
+/**
+ * dgrp_chk_perm() -- check permissions for net device
+ * @inode: pointer to inode structure for the net communication device
+ * @op: operation to be tested
+ *
+ * The file permissions and ownerships are tested to determine whether
+ * the operation "op" is permitted on the file pointed to by the inode.
+ * Returns 0 if the operation is permitted, -EACCESS otherwise
+ */
+int dgrp_chk_perm(int mode, int op)
+{
+	if (!current_euid())
+		mode >>= 6;
+	else if (in_egroup_p(0))
+		mode >>= 3;
+
+	if ((mode & op & 0007) == op)
+		return 0;
+
+	if (capable(CAP_SYS_ADMIN))
+		return 0;
+
+	return -EACCES;
+}
+
+/* dgrp_chk_perm wrapper for permission call in struct inode_operations */
+int dgrp_inode_permission(struct inode *inode, int op)
+{
+	return dgrp_chk_perm(inode->i_mode, op);
+}
diff --git a/drivers/staging/dgrp/dgrp_common.h b/drivers/staging/dgrp/dgrp_common.h
new file mode 100644
index 000000000000..05ff338471ac
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_common.h
@@ -0,0 +1,208 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+#ifndef __DGRP_COMMON_H
+#define __DGRP_COMMON_H
+
+#define DIGI_VERSION "1.9-29"
+
+#include <linux/fs.h>
+#include <linux/timer.h>
+#include "drp.h"
+
+#define DGRP_TTIME 100
+#define DGRP_RTIME 100
+
+/************************************************************************
+ * All global storage allocation.
+ ************************************************************************/
+
+extern int dgrp_rawreadok;  /* Allow raw writing of input */
+extern int dgrp_register_cudevices; /* enable legacy cu devices */
+extern int dgrp_register_prdevices; /* enable transparent print devices */
+extern int dgrp_poll_tick;          /* Poll interval - in ms */
+
+extern struct list_head nd_struct_list;
+
+struct dgrp_poll_data {
+	spinlock_t poll_lock;
+	struct timer_list timer;
+	int poll_tick;
+	ulong poll_round;	/* Timer rouding factor */
+	long node_active_count;
+};
+
+extern struct dgrp_poll_data dgrp_poll_data;
+extern void dgrp_poll_handler(unsigned long arg);
+
+/* from dgrp_mon_ops.c */
+extern void dgrp_register_mon_hook(struct proc_dir_entry *de);
+
+/* from dgrp_tty.c */
+extern int dgrp_tty_init(struct nd_struct *nd);
+extern void dgrp_tty_uninit(struct nd_struct *nd);
+
+/* from dgrp_ports_ops.c */
+extern void dgrp_register_ports_hook(struct proc_dir_entry *de);
+
+/* from dgrp_net_ops.c */
+extern void dgrp_register_net_hook(struct proc_dir_entry *de);
+
+/* from dgrp_dpa_ops.c */
+extern void dgrp_register_dpa_hook(struct proc_dir_entry *de);
+extern void dgrp_dpa_data(struct nd_struct *, int, u8 *, int);
+
+/* from dgrp_sysfs.c */
+extern void dgrp_create_class_sysfs_files(void);
+extern void dgrp_remove_class_sysfs_files(void);
+
+extern void dgrp_create_node_class_sysfs_files(struct nd_struct *nd);
+extern void dgrp_remove_node_class_sysfs_files(struct nd_struct *nd);
+
+extern void dgrp_create_tty_sysfs(struct un_struct *un, struct device *c);
+extern void dgrp_remove_tty_sysfs(struct device *c);
+
+/* from dgrp_specproc.c */
+/*
+ *  The list of DGRP entries with r/w capabilities.  These
+ *  magic numbers are used for identification purposes.
+ */
+enum {
+	DGRP_CONFIG = 1,	/* Configure portservers */
+	DGRP_NETDIR = 2,	/* Directory for "net" devices */
+	DGRP_MONDIR = 3,	/* Directory for "mon" devices */
+	DGRP_PORTSDIR = 4,	/* Directory for "ports" devices */
+	DGRP_INFO = 5,		/* Get info. about the running module */
+	DGRP_NODEINFO = 6,	/* Get info. about the configured nodes */
+	DGRP_DPADIR = 7,	/* Directory for the "dpa" devices */
+};
+
+/*
+ *  Directions for proc handlers
+ */
+enum {
+	INBOUND = 1,		/* Data being written to kernel */
+	OUTBOUND = 2,		/* Data being read from the kernel */
+};
+
+/**
+ * dgrp_proc_entry: structure for dgrp proc dirs
+ * @id: ID number associated with this particular entry.  Should be
+ *    unique across all of DGRP.
+ * @name: text name associated with the /proc entry
+ * @mode: file access permisssions for the /proc entry
+ * @child: pointer to table describing a subdirectory for this entry
+ * @de: pointer to directory entry for this object once registered.  Used
+ *    to grab the handle of the object for unregistration
+ * @excl_sem: semaphore to provide exclusive to struct
+ * @excl_cnt: counter of current accesses
+ *
+ *  Each entry in a DGRP proc directory is described with a
+ *  dgrp_proc_entry structure.  A collection of these
+ *  entries (in an array) represents the members associated
+ *  with a particular /proc directory, and is referred to
+ *  as a table.  All tables are terminated by an entry with
+ *  zeros for every member.
+ */
+struct dgrp_proc_entry {
+	int                  id;          /* Integer identifier */
+	const char        *name;          /* ASCII identifier */
+	mode_t             mode;          /* File access permissions */
+	struct dgrp_proc_entry *child;    /* Child pointer */
+
+	/* file ops to use, pass NULL to use default */
+	struct file_operations *proc_file_ops;
+
+	struct proc_dir_entry *de;        /* proc entry pointer */
+	struct semaphore   excl_sem;      /* Protects exclusive access var */
+	int                excl_cnt;      /* Counts number of curr accesses */
+};
+
+extern void dgrp_unregister_proc(void);
+extern void dgrp_register_proc(void);
+
+/*-----------------------------------------------------------------------*
+ *
+ *  Declarations for common operations:
+ *
+ *      (either used by more than one of net, mon, or tty,
+ *       or in interrupt context (i.e. the poller))
+ *
+ *-----------------------------------------------------------------------*/
+
+void dgrp_carrier(struct ch_struct *ch);
+extern int dgrp_inode_permission(struct inode *inode, int op);
+extern int dgrp_chk_perm(int mode, int op);
+
+
+/*
+ *  ID manipulation macros (where c1 & c2 are characters, i is
+ *  a long integer, and s is a character array of at least three members
+ */
+
+static inline void ID_TO_CHAR(long i, char *s)
+{
+	s[0] = ((i & 0xff00)>>8);
+	s[1] = (i & 0xff);
+	s[2] = 0;
+}
+
+static inline long CHAR_TO_ID(char *s)
+{
+	return ((s[0] & 0xff) << 8) | (s[1] & 0xff);
+}
+
+static inline struct nd_struct *nd_struct_get(long major)
+{
+	struct nd_struct *nd;
+
+	list_for_each_entry(nd, &nd_struct_list, list) {
+		if (major == nd->nd_major)
+			return nd;
+	}
+
+	return NULL;
+}
+
+static inline int nd_struct_add(struct nd_struct *entry)
+{
+	struct nd_struct *ptr;
+
+	ptr = nd_struct_get(entry->nd_major);
+
+	if (ptr)
+		return -EBUSY;
+
+	list_add_tail(&entry->list, &nd_struct_list);
+
+	return 0;
+}
+
+static inline int nd_struct_del(struct nd_struct *entry)
+{
+	struct nd_struct *nd;
+
+	nd = nd_struct_get(entry->nd_major);
+
+	if (!nd)
+		return -ENODEV;
+
+	list_del(&nd->list);
+	return 0;
+}
+
+#endif /* __DGRP_COMMON_H */
diff --git a/drivers/staging/dgrp/dgrp_dpa_ops.c b/drivers/staging/dgrp/dgrp_dpa_ops.c
new file mode 100644
index 000000000000..49e670915e5c
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_dpa_ops.c
@@ -0,0 +1,556 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_dpa_ops.c
+ *
+ *  Description:
+ *
+ *     Handle the file operations required for the "dpa" devices.
+ *     Includes those functions required to register the "dpa" devices
+ *     in "/proc".
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/tty.h>
+#include <linux/poll.h>
+#include <linux/cred.h>
+#include <linux/sched.h>
+#include <linux/ratelimit.h>
+#include <asm/unaligned.h>
+
+#include "dgrp_common.h"
+
+/* File operation declarations */
+static int dgrp_dpa_open(struct inode *, struct file *);
+static int dgrp_dpa_release(struct inode *, struct file *);
+static ssize_t dgrp_dpa_read(struct file *, char __user *, size_t, loff_t *);
+static long dgrp_dpa_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg);
+static unsigned int dgrp_dpa_select(struct file *, struct poll_table_struct *);
+
+static const struct file_operations dpa_ops = {
+	.owner   =  THIS_MODULE,
+	.read    =  dgrp_dpa_read,
+	.poll    =  dgrp_dpa_select,
+	.unlocked_ioctl =  dgrp_dpa_ioctl,
+	.open    =  dgrp_dpa_open,
+	.release =  dgrp_dpa_release,
+};
+
+static struct inode_operations dpa_inode_ops = {
+	.permission = dgrp_inode_permission
+};
+
+
+
+struct digi_node {
+	uint	nd_state;		/* Node state: 1 = up, 0 = down. */
+	uint	nd_chan_count;		/* Number of channels found */
+	uint	nd_tx_byte;		/* Tx data count */
+	uint	nd_rx_byte;		/* RX data count */
+	u8	nd_ps_desc[MAX_DESC_LEN]; /* Description from PS */
+};
+
+#define DIGI_GETNODE      (('d'<<8) | 249)	/* get board info */
+
+
+struct digi_chan {
+	uint	ch_port;	/* Port number to get info on */
+	uint	ch_open;	/* 1 if open, 0 if not */
+	uint	ch_txcount;	/* TX data count  */
+	uint	ch_rxcount;	/* RX data count  */
+	uint	ch_s_brate;	/* Realport BRATE */
+	uint	ch_s_estat;	/* Realport ELAST */
+	uint	ch_s_cflag;	/* Realport CFLAG */
+	uint	ch_s_iflag;	/* Realport IFLAG */
+	uint	ch_s_oflag;	/* Realport OFLAG */
+	uint	ch_s_xflag;	/* Realport XFLAG */
+	uint	ch_s_mstat;	/* Realport MLAST */
+};
+
+#define DIGI_GETCHAN      (('d'<<8) | 248)	/* get channel info */
+
+
+struct digi_vpd {
+	int vpd_len;
+	char vpd_data[VPDSIZE];
+};
+
+#define DIGI_GETVPD       (('d'<<8) | 246)	/* get VPD info */
+
+
+struct digi_debug {
+	int onoff;
+	int port;
+};
+
+#define DIGI_SETDEBUG      (('d'<<8) | 247)	/* set debug info */
+
+
+void dgrp_register_dpa_hook(struct proc_dir_entry *de)
+{
+	struct nd_struct *node = de->data;
+
+	de->proc_iops = &dpa_inode_ops;
+	de->proc_fops = &dpa_ops;
+
+	node->nd_dpa_de = de;
+	spin_lock_init(&node->nd_dpa_lock);
+}
+
+/*
+ * dgrp_dpa_open -- open the DPA device for a particular PortServer
+ */
+static int dgrp_dpa_open(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+	int rtn = 0;
+
+	struct proc_dir_entry *de;
+
+	rtn = try_module_get(THIS_MODULE);
+	if (!rtn)
+		return -ENXIO;
+
+	rtn = 0;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		rtn = -EPERM;
+		goto done;
+	}
+
+	/*
+	 *  Make sure that the "private_data" field hasn't already been used.
+	 */
+	if (file->private_data) {
+		rtn = -EINVAL;
+		goto done;
+	}
+
+	/*
+	 *  Get the node pointer, and fail if it doesn't exist.
+	 */
+	de = PDE(inode);
+	if (!de) {
+		rtn = -ENXIO;
+		goto done;
+	}
+	nd = (struct nd_struct *)de->data;
+	if (!nd) {
+		rtn = -ENXIO;
+		goto done;
+	}
+
+	file->private_data = (void *) nd;
+
+	/*
+	 * Allocate the DPA buffer.
+	 */
+
+	if (nd->nd_dpa_buf) {
+		rtn = -EBUSY;
+	} else {
+		nd->nd_dpa_buf = kmalloc(DPA_MAX, GFP_KERNEL);
+
+		if (!nd->nd_dpa_buf) {
+			rtn = -ENOMEM;
+		} else {
+			nd->nd_dpa_out = 0;
+			nd->nd_dpa_in = 0;
+			nd->nd_dpa_lbolt = jiffies;
+		}
+	}
+
+done:
+
+	if (rtn)
+		module_put(THIS_MODULE);
+	return rtn;
+}
+
+/*
+ * dgrp_dpa_release -- close the DPA device for a particular PortServer
+ */
+static int dgrp_dpa_release(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+	u8 *buf;
+	unsigned long lock_flags;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		goto done;
+
+	/*
+	 *  Free the dpa buffer.
+	 */
+
+	spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+
+	buf = nd->nd_dpa_buf;
+
+	nd->nd_dpa_buf = NULL;
+	nd->nd_dpa_out = nd->nd_dpa_in;
+
+	/*
+	 *  Wakeup any thread waiting for buffer space.
+	 */
+
+	if (nd->nd_dpa_flag & DPA_WAIT_SPACE) {
+		nd->nd_dpa_flag &= ~DPA_WAIT_SPACE;
+		wake_up_interruptible(&nd->nd_dpa_wqueue);
+	}
+
+	spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+
+	kfree(buf);
+
+done:
+	module_put(THIS_MODULE);
+	file->private_data = NULL;
+	return 0;
+}
+
+/*
+ * dgrp_dpa_read
+ *
+ * Copy data from the monitoring buffer to the user, freeing space
+ * in the monitoring buffer for more messages
+ */
+static ssize_t dgrp_dpa_read(struct file *file, char __user *buf, size_t count,
+			     loff_t *ppos)
+{
+	struct nd_struct *nd;
+	int n;
+	int r;
+	int offset = 0;
+	int res = 0;
+	ssize_t rtn;
+	unsigned long lock_flags;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		return -ENXIO;
+
+	/*
+	 *  Wait for some data to appear in the buffer.
+	 */
+
+	spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+
+	for (;;) {
+		n = (nd->nd_dpa_in - nd->nd_dpa_out) & DPA_MASK;
+
+		if (n != 0)
+			break;
+
+		nd->nd_dpa_flag |= DPA_WAIT_DATA;
+
+		spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+
+		/*
+		 * Go to sleep waiting until the condition becomes true.
+		 */
+		rtn = wait_event_interruptible(nd->nd_dpa_wqueue,
+			((nd->nd_dpa_flag & DPA_WAIT_DATA) == 0));
+
+		if (rtn)
+			return rtn;
+
+		spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+	}
+
+	/*
+	 *  Read whatever is there.
+	 */
+
+	if (n > count)
+		n = count;
+
+	res = n;
+
+	r = DPA_MAX - nd->nd_dpa_out;
+
+	if (r <= n) {
+
+		spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+		rtn = copy_to_user((void __user *)buf,
+				   nd->nd_dpa_buf + nd->nd_dpa_out, r);
+		spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+
+		if (rtn) {
+			rtn = -EFAULT;
+			goto done;
+		}
+
+		nd->nd_dpa_out = 0;
+		n -= r;
+		offset = r;
+	}
+
+	spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+	rtn = copy_to_user((void __user *)buf + offset,
+			   nd->nd_dpa_buf + nd->nd_dpa_out, n);
+	spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+
+	if (rtn) {
+		rtn = -EFAULT;
+		goto done;
+	}
+
+	nd->nd_dpa_out += n;
+
+	*ppos += res;
+
+	rtn = res;
+
+	/*
+	 *  Wakeup any thread waiting for buffer space.
+	 */
+
+	n = (nd->nd_dpa_in - nd->nd_dpa_out) & DPA_MASK;
+
+	if (nd->nd_dpa_flag & DPA_WAIT_SPACE &&
+	    (DPA_MAX - n) > DPA_HIGH_WATER) {
+		nd->nd_dpa_flag &= ~DPA_WAIT_SPACE;
+		wake_up_interruptible(&nd->nd_dpa_wqueue);
+	}
+
+ done:
+	spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+	return rtn;
+}
+
+static unsigned int dgrp_dpa_select(struct file *file,
+				    struct poll_table_struct *table)
+{
+	unsigned int retval = 0;
+	struct nd_struct *nd = file->private_data;
+
+	if (nd->nd_dpa_out != nd->nd_dpa_in)
+		retval |= POLLIN | POLLRDNORM; /* Conditionally readable */
+
+	retval |= POLLOUT | POLLWRNORM;        /* Always writeable */
+
+	return retval;
+}
+
+static long dgrp_dpa_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+
+	struct nd_struct  *nd;
+	struct digi_chan getchan;
+	struct digi_node getnode;
+	struct ch_struct *ch;
+	struct digi_debug setdebug;
+	struct digi_vpd vpd;
+	unsigned int port;
+	void __user *uarg = (void __user *) arg;
+
+	nd = file->private_data;
+
+	switch (cmd) {
+	case DIGI_GETCHAN:
+		if (copy_from_user(&getchan, uarg, sizeof(struct digi_chan)))
+			return -EFAULT;
+
+		port = getchan.ch_port;
+
+		if (port < 0 || port > nd->nd_chan_count)
+			return -EINVAL;
+
+		ch = nd->nd_chan + port;
+
+		getchan.ch_open = (ch->ch_open_count > 0) ? 1 : 0;
+		getchan.ch_txcount = ch->ch_txcount;
+		getchan.ch_rxcount = ch->ch_rxcount;
+		getchan.ch_s_brate = ch->ch_s_brate;
+		getchan.ch_s_estat = ch->ch_s_elast;
+		getchan.ch_s_cflag = ch->ch_s_cflag;
+		getchan.ch_s_iflag = ch->ch_s_iflag;
+		getchan.ch_s_oflag = ch->ch_s_oflag;
+		getchan.ch_s_xflag = ch->ch_s_xflag;
+		getchan.ch_s_mstat = ch->ch_s_mlast;
+
+		if (copy_to_user(uarg, &getchan, sizeof(struct digi_chan)))
+			return -EFAULT;
+		break;
+
+
+	case DIGI_GETNODE:
+		getnode.nd_state = (nd->nd_state & NS_READY) ? 1 : 0;
+		getnode.nd_chan_count = nd->nd_chan_count;
+		getnode.nd_tx_byte = nd->nd_tx_byte;
+		getnode.nd_rx_byte = nd->nd_rx_byte;
+
+		memset(&getnode.nd_ps_desc, 0, MAX_DESC_LEN);
+		strncpy(getnode.nd_ps_desc, nd->nd_ps_desc, MAX_DESC_LEN);
+
+		if (copy_to_user(uarg, &getnode, sizeof(struct digi_node)))
+			return -EFAULT;
+		break;
+
+
+	case DIGI_SETDEBUG:
+		if (copy_from_user(&setdebug, uarg, sizeof(struct digi_debug)))
+			return -EFAULT;
+
+		nd->nd_dpa_debug = setdebug.onoff;
+		nd->nd_dpa_port = setdebug.port;
+		break;
+
+
+	case DIGI_GETVPD:
+		if (nd->nd_vpd_len > 0) {
+			vpd.vpd_len = nd->nd_vpd_len;
+			memcpy(&vpd.vpd_data, &nd->nd_vpd, nd->nd_vpd_len);
+		} else {
+			vpd.vpd_len = 0;
+		}
+
+		if (copy_to_user(uarg, &vpd, sizeof(struct digi_vpd)))
+			return -EFAULT;
+		break;
+	}
+
+	return 0;
+}
+
+/**
+ * dgrp_dpa() -- send data to the device monitor queue
+ * @nd: pointer to a node structure
+ * @buf: buffer of data to copy to the monitoring buffer
+ * @len: number of bytes to transfer to the buffer
+ *
+ * Called by the net device routines to send data to the device
+ * monitor queue.  If the device monitor buffer is too full to
+ * accept the data, it waits until the buffer is ready.
+ */
+static void dgrp_dpa(struct nd_struct *nd, u8 *buf, int nbuf)
+{
+	int n;
+	int r;
+	unsigned long lock_flags;
+
+	/*
+	 *  Grab DPA lock.
+	 */
+	spin_lock_irqsave(&nd->nd_dpa_lock, lock_flags);
+
+	/*
+	 *  Loop while data remains.
+	 */
+	while (nbuf > 0 && nd->nd_dpa_buf != NULL) {
+
+		n = (nd->nd_dpa_out - nd->nd_dpa_in - 1) & DPA_MASK;
+
+		/*
+		 * Enforce flow control on the DPA device.
+		 */
+		if (n < (DPA_MAX - DPA_HIGH_WATER))
+			nd->nd_dpa_flag |= DPA_WAIT_SPACE;
+
+		/*
+		 * This should never happen, as the flow control above
+		 * should have stopped things before they got to this point.
+		 */
+		if (n == 0) {
+			spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+			return;
+		}
+
+		/*
+		 * Copy as much data as will fit.
+		 */
+
+		if (n > nbuf)
+			n = nbuf;
+
+		r = DPA_MAX - nd->nd_dpa_in;
+
+		if (r <= n) {
+			memcpy(nd->nd_dpa_buf + nd->nd_dpa_in, buf, r);
+
+			n -= r;
+
+			nd->nd_dpa_in = 0;
+
+			buf += r;
+			nbuf -= r;
+		}
+
+		memcpy(nd->nd_dpa_buf + nd->nd_dpa_in, buf, n);
+
+		nd->nd_dpa_in += n;
+
+		buf += n;
+		nbuf -= n;
+
+		if (nd->nd_dpa_in >= DPA_MAX)
+			pr_info_ratelimited("%s - nd->nd_dpa_in (%i) >= DPA_MAX\n",
+					    __func__, nd->nd_dpa_in);
+
+		/*
+		 *  Wakeup any thread waiting for data
+		 */
+		if (nd->nd_dpa_flag & DPA_WAIT_DATA) {
+			nd->nd_dpa_flag &= ~DPA_WAIT_DATA;
+			wake_up_interruptible(&nd->nd_dpa_wqueue);
+		}
+	}
+
+	/*
+	 *  Release the DPA lock.
+	 */
+	spin_unlock_irqrestore(&nd->nd_dpa_lock, lock_flags);
+}
+
+/**
+ * dgrp_monitor_data() -- builds a DPA data packet
+ * @nd: pointer to a node structure
+ * @type: type of message to be logged in the DPA buffer
+ * @buf: buffer of data to be logged in the DPA buffer
+ * @size -- number of bytes in the "buf" buffer
+ */
+void dgrp_dpa_data(struct nd_struct *nd, int type, u8 *buf, int size)
+{
+	u8 header[5];
+
+	header[0] = type;
+
+	put_unaligned_be32(size, header + 1);
+
+	dgrp_dpa(nd, header, sizeof(header));
+	dgrp_dpa(nd, buf, size);
+}
diff --git a/drivers/staging/dgrp/dgrp_driver.c b/drivers/staging/dgrp/dgrp_driver.c
new file mode 100644
index 000000000000..6e4a0ebc0749
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_driver.c
@@ -0,0 +1,110 @@
+/*
+ *
+ * Copyright 1999-2003 Digi International (www.digi.com)
+ *     Jeff Randall
+ *     James Puzzo  <jamesp at digi dot com>
+ *     Scott Kilau  <Scott_Kilau at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *	Driver specific includes
+ */
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/init.h>
+
+/*
+ *  PortServer includes
+ */
+#include "dgrp_common.h"
+
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Digi International, http://www.digi.com");
+MODULE_DESCRIPTION("RealPort driver for Digi's ethernet-based serial connectivity product line");
+MODULE_VERSION(DIGI_VERSION);
+
+struct list_head nd_struct_list;
+struct dgrp_poll_data dgrp_poll_data;
+
+int dgrp_rawreadok = 1;		/* Bypass flipbuf on input */
+int dgrp_register_cudevices = 1;/* Turn on/off registering legacy cu devices */
+int dgrp_register_prdevices = 1;/* Turn on/off registering transparent print */
+int dgrp_poll_tick = 20;	/* Poll interval - in ms */
+
+module_param_named(rawreadok, dgrp_rawreadok, int, 0644);
+MODULE_PARM_DESC(rawreadok, "Bypass flip buffers on input");
+
+module_param_named(register_cudevices, dgrp_register_cudevices, int, 0644);
+MODULE_PARM_DESC(register_cudevices, "Turn on/off registering legacy cu devices");
+
+module_param_named(register_prdevices, dgrp_register_prdevices, int, 0644);
+MODULE_PARM_DESC(register_prdevices, "Turn on/off registering transparent print devices");
+
+module_param_named(pollrate, dgrp_poll_tick, int, 0644);
+MODULE_PARM_DESC(pollrate, "Poll interval in ms");
+
+/* Driver load/unload functions */
+static int dgrp_init_module(void);
+static void dgrp_cleanup_module(void);
+
+module_init(dgrp_init_module);
+module_exit(dgrp_cleanup_module);
+
+/*
+ * init_module()
+ *
+ * Module load.  This is where it all starts.
+ */
+static int dgrp_init_module(void)
+{
+	INIT_LIST_HEAD(&nd_struct_list);
+
+	spin_lock_init(&dgrp_poll_data.poll_lock);
+	init_timer(&dgrp_poll_data.timer);
+	dgrp_poll_data.poll_tick = dgrp_poll_tick;
+	dgrp_poll_data.timer.function = dgrp_poll_handler;
+	dgrp_poll_data.timer.data = (unsigned long) &dgrp_poll_data;
+
+	dgrp_create_class_sysfs_files();
+
+	dgrp_register_proc();
+
+	return 0;
+}
+
+
+/*
+ *	Module unload.  This is where it all ends.
+ */
+static void dgrp_cleanup_module(void)
+{
+	struct nd_struct *nd, *next;
+
+	/*
+	 *	Attempting to free resources in backwards
+	 *	order of allocation, in case that helps
+	 *	memory pool fragmentation.
+	 */
+	dgrp_unregister_proc();
+
+	dgrp_remove_class_sysfs_files();
+
+
+	list_for_each_entry_safe(nd, next, &nd_struct_list, list) {
+		dgrp_tty_uninit(nd);
+		kfree(nd);
+	}
+}
diff --git a/drivers/staging/dgrp/dgrp_mon_ops.c b/drivers/staging/dgrp/dgrp_mon_ops.c
new file mode 100644
index 000000000000..268dcb95204b
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_mon_ops.c
@@ -0,0 +1,346 @@
+/*****************************************************************************
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_mon_ops.c
+ *
+ *  Description:
+ *
+ *     Handle the file operations required for the "monitor" devices.
+ *     Includes those functions required to register the "mon" devices
+ *     in "/proc".
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/sched.h>
+#include <asm/unaligned.h>
+#include <linux/proc_fs.h>
+
+#include "dgrp_common.h"
+
+/* File operation declarations */
+static int dgrp_mon_open(struct inode *, struct file *);
+static int dgrp_mon_release(struct inode *, struct file *);
+static ssize_t dgrp_mon_read(struct file *, char __user *, size_t, loff_t *);
+static long dgrp_mon_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg);
+
+static const struct file_operations mon_ops = {
+	.owner   = THIS_MODULE,
+	.read    = dgrp_mon_read,
+	.unlocked_ioctl = dgrp_mon_ioctl,
+	.open    = dgrp_mon_open,
+	.release = dgrp_mon_release,
+};
+
+static struct inode_operations mon_inode_ops = {
+	.permission = dgrp_inode_permission
+};
+
+void dgrp_register_mon_hook(struct proc_dir_entry *de)
+{
+	struct nd_struct *node = de->data;
+
+	de->proc_iops = &mon_inode_ops;
+	de->proc_fops = &mon_ops;
+	node->nd_mon_de = de;
+	sema_init(&node->nd_mon_semaphore, 1);
+}
+
+/**
+ * dgrp_mon_open() -- open /proc/dgrp/ports device for a PortServer
+ * @inode: struct inode *
+ * @file: struct file *
+ *
+ * Open function to open the /proc/dgrp/ports device for a PortServer.
+ */
+static int dgrp_mon_open(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+	struct proc_dir_entry *de;
+	struct timeval tv;
+	uint32_t time;
+	u8 *buf;
+	int rtn;
+
+	rtn = try_module_get(THIS_MODULE);
+	if (!rtn)
+		return -ENXIO;
+
+	rtn = 0;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		rtn = -EPERM;
+		goto done;
+	}
+
+	/*
+	 *  Make sure that the "private_data" field hasn't already been used.
+	 */
+	if (file->private_data) {
+		rtn = -EINVAL;
+		goto done;
+	}
+
+	/*
+	 *  Get the node pointer, and fail if it doesn't exist.
+	 */
+	de = PDE(inode);
+	if (!de) {
+		rtn = -ENXIO;
+		goto done;
+	}
+
+	nd = (struct nd_struct *)de->data;
+	if (!nd) {
+		rtn = -ENXIO;
+		goto done;
+	}
+
+	file->private_data = (void *) nd;
+
+	/*
+	 * Allocate the monitor buffer.
+	 */
+
+	/*
+	 *  Grab the MON lock.
+	 */
+	down(&nd->nd_mon_semaphore);
+
+	if (nd->nd_mon_buf) {
+		rtn = -EBUSY;
+		goto done_up;
+	}
+
+	nd->nd_mon_buf = kmalloc(MON_MAX, GFP_KERNEL);
+
+	if (!nd->nd_mon_buf) {
+		rtn = -ENOMEM;
+		goto done_up;
+	}
+
+	/*
+	 *  Enter an RPDUMP file header into the buffer.
+	 */
+
+	buf = nd->nd_mon_buf;
+
+	strcpy(buf, RPDUMP_MAGIC);
+	buf += strlen(buf) + 1;
+
+	do_gettimeofday(&tv);
+
+	/*
+	 *  tv.tv_sec might be a 64 bit quantity.  Pare
+	 *  it down to 32 bits before attempting to encode
+	 *  it.
+	 */
+	time = (uint32_t) (tv.tv_sec & 0xffffffff);
+
+	put_unaligned_be32(time, buf);
+	put_unaligned_be16(0, buf + 4);
+	buf += 6;
+
+	if (nd->nd_tx_module) {
+		buf[0] = RPDUMP_CLIENT;
+		put_unaligned_be32(0, buf + 1);
+		put_unaligned_be16(1, buf + 5);
+		buf[7] = 0xf0 + nd->nd_tx_module;
+		buf += 8;
+	}
+
+	if (nd->nd_rx_module) {
+		buf[0] = RPDUMP_SERVER;
+		put_unaligned_be32(0, buf + 1);
+		put_unaligned_be16(1, buf + 5);
+		buf[7] = 0xf0 + nd->nd_rx_module;
+		buf += 8;
+	}
+
+	nd->nd_mon_out = 0;
+	nd->nd_mon_in  = buf - nd->nd_mon_buf;
+	nd->nd_mon_lbolt = jiffies;
+
+done_up:
+	up(&nd->nd_mon_semaphore);
+
+done:
+	if (rtn)
+		module_put(THIS_MODULE);
+	return rtn;
+}
+
+
+/**
+ * dgrp_mon_release() - Close the MON device for a particular PortServer
+ * @inode: struct inode *
+ * @file: struct file *
+ */
+static int dgrp_mon_release(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		goto done;
+
+	/*
+	 *  Free the monitor buffer.
+	 */
+
+	down(&nd->nd_mon_semaphore);
+
+	kfree(nd->nd_mon_buf);
+	nd->nd_mon_buf = NULL;
+	nd->nd_mon_out = nd->nd_mon_in;
+
+	/*
+	 *  Wakeup any thread waiting for buffer space.
+	 */
+
+	if (nd->nd_mon_flag & MON_WAIT_SPACE) {
+		nd->nd_mon_flag &= ~MON_WAIT_SPACE;
+		wake_up_interruptible(&nd->nd_mon_wqueue);
+	}
+
+	up(&nd->nd_mon_semaphore);
+
+	/*
+	 *  Make sure there is no thread in the middle of writing a packet.
+	 */
+	down(&nd->nd_net_semaphore);
+	up(&nd->nd_net_semaphore);
+
+done:
+	module_put(THIS_MODULE);
+	file->private_data = NULL;
+	return 0;
+}
+
+/**
+ * dgrp_mon_read() -- Copy data from the monitoring buffer to the user
+ */
+static ssize_t dgrp_mon_read(struct file *file, char __user *buf, size_t count,
+			     loff_t *ppos)
+{
+	struct nd_struct *nd;
+	int r;
+	int offset = 0;
+	int res = 0;
+	ssize_t rtn;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		return -ENXIO;
+
+	/*
+	 *  Wait for some data to appear in the buffer.
+	 */
+
+	down(&nd->nd_mon_semaphore);
+
+	for (;;) {
+		res = (nd->nd_mon_in - nd->nd_mon_out) & MON_MASK;
+
+		if (res)
+			break;
+
+		nd->nd_mon_flag |= MON_WAIT_DATA;
+
+		up(&nd->nd_mon_semaphore);
+
+		/*
+		 * Go to sleep waiting until the condition becomes true.
+		 */
+		rtn = wait_event_interruptible(nd->nd_mon_wqueue,
+					       ((nd->nd_mon_flag & MON_WAIT_DATA) == 0));
+
+		if (rtn)
+			return rtn;
+
+		down(&nd->nd_mon_semaphore);
+	}
+
+	/*
+	 *  Read whatever is there.
+	 */
+
+	if (res > count)
+		res = count;
+
+	r = MON_MAX - nd->nd_mon_out;
+
+	if (r <= res) {
+		rtn = copy_to_user((void __user *)buf,
+				   nd->nd_mon_buf + nd->nd_mon_out, r);
+		if (rtn) {
+			up(&nd->nd_mon_semaphore);
+			return -EFAULT;
+		}
+
+		nd->nd_mon_out = 0;
+		res -= r;
+		offset = r;
+	}
+
+	rtn = copy_to_user((void __user *) buf + offset,
+			   nd->nd_mon_buf + nd->nd_mon_out, res);
+	if (rtn) {
+		up(&nd->nd_mon_semaphore);
+		return -EFAULT;
+	}
+
+	nd->nd_mon_out += res;
+
+	*ppos += res;
+
+	up(&nd->nd_mon_semaphore);
+
+	/*
+	 *  Wakeup any thread waiting for buffer space.
+	 */
+
+	if (nd->nd_mon_flag & MON_WAIT_SPACE) {
+		nd->nd_mon_flag &= ~MON_WAIT_SPACE;
+		wake_up_interruptible(&nd->nd_mon_wqueue);
+	}
+
+	return res;
+}
+
+/*  ioctl is not valid on monitor device */
+static long dgrp_mon_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	return -EINVAL;
+}
diff --git a/drivers/staging/dgrp/dgrp_net_ops.c b/drivers/staging/dgrp/dgrp_net_ops.c
new file mode 100644
index 000000000000..d9d6b6709e4e
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_net_ops.c
@@ -0,0 +1,3731 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo  <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_net_ops.c
+ *
+ *  Description:
+ *
+ *     Handle the file operations required for the "network" devices.
+ *     Includes those functions required to register the "net" devices
+ *     in "/proc".
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/spinlock.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/ratelimit.h>
+#include <asm/unaligned.h>
+
+#define MYFLIPLEN	TBUF_MAX
+
+#include "dgrp_common.h"
+
+#define TTY_FLIPBUF_SIZE 512
+#define DEVICE_NAME_SIZE 50
+
+/*
+ *  Generic helper function declarations
+ */
+static void   parity_scan(struct ch_struct *ch, unsigned char *cbuf,
+				unsigned char *fbuf, int *len);
+
+/*
+ *  File operation declarations
+ */
+static int dgrp_net_open(struct inode *, struct file *);
+static int dgrp_net_release(struct inode *, struct file *);
+static ssize_t dgrp_net_read(struct file *, char __user *, size_t, loff_t *);
+static ssize_t dgrp_net_write(struct file *, const char __user *, size_t,
+			      loff_t *);
+static long dgrp_net_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg);
+static unsigned int dgrp_net_select(struct file *file,
+				    struct poll_table_struct *table);
+
+static const struct file_operations net_ops = {
+	.owner   =  THIS_MODULE,
+	.read    =  dgrp_net_read,
+	.write   =  dgrp_net_write,
+	.poll    =  dgrp_net_select,
+	.unlocked_ioctl =  dgrp_net_ioctl,
+	.open    =  dgrp_net_open,
+	.release =  dgrp_net_release,
+};
+
+static struct inode_operations net_inode_ops = {
+	.permission = dgrp_inode_permission
+};
+
+void dgrp_register_net_hook(struct proc_dir_entry *de)
+{
+	struct nd_struct *node = de->data;
+
+	de->proc_iops = &net_inode_ops;
+	de->proc_fops = &net_ops;
+	node->nd_net_de = de;
+	sema_init(&node->nd_net_semaphore, 1);
+	node->nd_state = NS_CLOSED;
+	dgrp_create_node_class_sysfs_files(node);
+}
+
+
+/**
+ * dgrp_dump() -- prints memory for debugging purposes.
+ * @mem: Memory location which should be printed to the console
+ * @len: Number of bytes to be dumped
+ */
+static void dgrp_dump(u8 *mem, int len)
+{
+	int i;
+
+	pr_debug("dgrp dump length = %d, data = ", len);
+	for (i = 0; i < len; ++i)
+		pr_debug("%.2x ", mem[i]);
+	pr_debug("\n");
+}
+
+/**
+ * dgrp_read_data_block() -- Read a data block
+ * @ch: struct ch_struct *
+ * @flipbuf: u8 *
+ * @flipbuf_size: size of flipbuf
+ */
+static void dgrp_read_data_block(struct ch_struct *ch, u8 *flipbuf,
+				 int flipbuf_size)
+{
+	int t;
+	int n;
+
+	if (flipbuf_size <= 0)
+		return;
+
+	t = RBUF_MAX - ch->ch_rout;
+	n = flipbuf_size;
+
+	if (n >= t) {
+		memcpy(flipbuf, ch->ch_rbuf + ch->ch_rout, t);
+		flipbuf += t;
+		n -= t;
+		ch->ch_rout = 0;
+	}
+
+	memcpy(flipbuf, ch->ch_rbuf + ch->ch_rout, n);
+	flipbuf += n;
+	ch->ch_rout += n;
+}
+
+
+/**
+ * dgrp_input() -- send data to the line disipline
+ * @ch: pointer to channel struct
+ *
+ * Copys the rbuf to the flipbuf and sends to line discipline.
+ * Sends input buffer data to the line discipline.
+ *
+ * There are several modes to consider here:
+ *    rawreadok, tty->real_raw, and IF_PARMRK
+ */
+static void dgrp_input(struct ch_struct *ch)
+{
+	struct nd_struct *nd;
+	struct tty_struct *tty;
+	int remain;
+	int data_len;
+	int len;
+	int flip_len;
+	int tty_count;
+	ulong lock_flags;
+	struct tty_ldisc *ld;
+	u8  *myflipbuf;
+	u8  *myflipflagbuf;
+
+	if (!ch)
+		return;
+
+	nd = ch->ch_nd;
+
+	if (!nd)
+		return;
+
+	spin_lock_irqsave(&nd->nd_lock, lock_flags);
+
+	myflipbuf = nd->nd_inputbuf;
+	myflipflagbuf = nd->nd_inputflagbuf;
+
+	if (!ch->ch_open_count) {
+		ch->ch_rout = ch->ch_rin;
+		goto out;
+	}
+
+	if (ch->ch_tun.un_flag & UN_CLOSING) {
+		ch->ch_rout = ch->ch_rin;
+		goto out;
+	}
+
+	tty = (ch->ch_tun).un_tty;
+
+
+	if (!tty || tty->magic != TTY_MAGIC) {
+		ch->ch_rout = ch->ch_rin;
+		goto out;
+	}
+
+	tty_count = tty->count;
+	if (!tty_count) {
+		ch->ch_rout = ch->ch_rin;
+		goto out;
+	}
+
+	if (tty->closing || test_bit(TTY_CLOSING, &tty->flags)) {
+		ch->ch_rout = ch->ch_rin;
+		goto out;
+	}
+
+	spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+
+	/* Decide how much data we can send into the tty layer */
+	if (dgrp_rawreadok && tty->real_raw)
+		flip_len = MYFLIPLEN;
+	else
+		flip_len = TTY_FLIPBUF_SIZE;
+
+	/* data_len should be the number of chars that we read in */
+	data_len = (ch->ch_rin - ch->ch_rout) & RBUF_MASK;
+	remain = data_len;
+
+	/* len is the amount of data we are going to transfer here */
+	len = min(data_len, flip_len);
+
+	/* take into consideration length of ldisc */
+	len = min(len, (N_TTY_BUF_SIZE - 1) - tty->read_cnt);
+
+	ld = tty_ldisc_ref(tty);
+
+	/*
+	 * If we were unable to get a reference to the ld,
+	 * don't flush our buffer, and act like the ld doesn't
+	 * have any space to put the data right now.
+	 */
+	if (!ld) {
+		len = 0;
+	} else if (!ld->ops->receive_buf) {
+		spin_lock_irqsave(&nd->nd_lock, lock_flags);
+		ch->ch_rout = ch->ch_rin;
+		spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+		len = 0;
+	}
+
+	/* Check DPA flow control */
+	if ((nd->nd_dpa_debug) &&
+	    (nd->nd_dpa_flag & DPA_WAIT_SPACE) &&
+	    (nd->nd_dpa_port == MINOR(tty_devnum(ch->ch_tun.un_tty))))
+		len = 0;
+
+	if ((len) && !(ch->ch_flag & CH_RXSTOP)) {
+
+		dgrp_read_data_block(ch, myflipbuf, len);
+
+		/*
+		 * In high performance mode, we don't have to update
+		 * flag_buf or any of the counts or pointers into flip buf.
+		 */
+		if (!dgrp_rawreadok || !tty->real_raw) {
+			if (I_PARMRK(tty) || I_BRKINT(tty) || I_INPCK(tty))
+				parity_scan(ch, myflipbuf, myflipflagbuf, &len);
+			else
+				memset(myflipflagbuf, TTY_NORMAL, len);
+		}
+
+		if ((nd->nd_dpa_debug) &&
+		    (nd->nd_dpa_port == PORT_NUM(MINOR(tty_devnum(tty)))))
+			dgrp_dpa_data(nd, 1, myflipbuf, len);
+
+		/*
+		 * If we're doing raw reads, jam it right into the
+		 * line disc bypassing the flip buffers.
+		 */
+		if (dgrp_rawreadok && tty->real_raw)
+			ld->ops->receive_buf(tty, myflipbuf, NULL, len);
+		else {
+			len = tty_buffer_request_room(tty, len);
+			tty_insert_flip_string_flags(tty, myflipbuf,
+						     myflipflagbuf, len);
+
+			/* Tell the tty layer its okay to "eat" the data now */
+			tty_flip_buffer_push(tty);
+		}
+
+		ch->ch_rxcount += len;
+	}
+
+	if (ld)
+		tty_ldisc_deref(ld);
+
+	/*
+	 * Wake up any sleepers (maybe dgrp close) that might be waiting
+	 * for a channel flag state change.
+	 */
+	wake_up_interruptible(&ch->ch_flag_wait);
+	return;
+
+out:
+	spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+}
+
+
+/*
+ *  parity_scan
+ *
+ *  Loop to inspect each single character or 0xFF escape.
+ *
+ *  if PARMRK & ~DOSMODE:
+ *     0xFF  0xFF           Normal 0xFF character, escaped
+ *                          to eliminate confusion.
+ *     0xFF  0x00  0x00     Break
+ *     0xFF  0x00  CC       Error character CC.
+ *     CC                   Normal character CC.
+ *
+ *  if PARMRK & DOSMODE:
+ *     0xFF  0x18  0x00     Break
+ *     0xFF  0x08  0x00     Framing Error
+ *     0xFF  0x04  0x00     Parity error
+ *     0xFF  0x0C  0x00     Both Framing and Parity error
+ *
+ *  TODO:  do we need to do the XMODEM, XOFF, XON, XANY processing??
+ *         as per protocol
+ */
+static void parity_scan(struct ch_struct *ch, unsigned char *cbuf,
+			unsigned char *fbuf, int *len)
+{
+	int l = *len;
+	int count = 0;
+	int DOS = ((ch->ch_iflag & IF_DOSMODE) == 0 ? 0 : 1);
+	unsigned char *cout; /* character buffer */
+	unsigned char *fout; /* flag buffer */
+	unsigned char *in;
+	unsigned char c;
+
+	in = cbuf;
+	cout = cbuf;
+	fout = fbuf;
+
+	while (l--) {
+		c = *in;
+		in++;
+
+		switch (ch->ch_pscan_state) {
+		default:
+			/* reset to sanity and fall through */
+			ch->ch_pscan_state = 0 ;
+
+		case 0:
+			/* No FF seen yet */
+			if (c == 0xff) /* delete this character from stream */
+				ch->ch_pscan_state = 1;
+			else {
+				*cout++ = c;
+				*fout++ = TTY_NORMAL;
+				count += 1;
+			}
+			break;
+
+		case 1:
+			/* first FF seen */
+			if (c == 0xff) {
+				/* doubled ff, transform to single ff */
+				*cout++ = c;
+				*fout++ = TTY_NORMAL;
+				count += 1;
+				ch->ch_pscan_state = 0;
+			} else {
+				/* save value examination in next state */
+				ch->ch_pscan_savechar = c;
+				ch->ch_pscan_state = 2;
+			}
+			break;
+
+		case 2:
+			/* third character of ff sequence */
+			*cout++ = c;
+			if (DOS) {
+				if (ch->ch_pscan_savechar & 0x10)
+					*fout++ = TTY_BREAK;
+				else if (ch->ch_pscan_savechar & 0x08)
+					*fout++ = TTY_FRAME;
+				else
+					/*
+					 * either marked as a parity error,
+					 * indeterminate, or not in DOSMODE
+					 * call it a parity error
+					 */
+					*fout++ = TTY_PARITY;
+			} else {
+				/* case FF XX ?? where XX is not 00 */
+				if (ch->ch_pscan_savechar & 0xff) {
+					/* this should not happen */
+					pr_info("%s: parity_scan: error unexpected byte\n",
+						__func__);
+					*fout++ = TTY_PARITY;
+				}
+				/* case FF 00 XX where XX is not 00 */
+				else if (c == 0xff)
+					*fout++ = TTY_PARITY;
+				/* case FF 00 00 */
+				else
+					*fout++ = TTY_BREAK;
+
+			}
+			count += 1;
+			ch->ch_pscan_state = 0;
+		}
+	}
+	*len = count;
+}
+
+
+/**
+ * dgrp_net_idle() -- Idle the network connection
+ * @nd: pointer to node structure to idle
+ */
+static void dgrp_net_idle(struct nd_struct *nd)
+{
+	struct ch_struct *ch;
+	int i;
+
+	nd->nd_tx_work = 1;
+
+	nd->nd_state = NS_IDLE;
+	nd->nd_flag = 0;
+
+	for (i = nd->nd_seq_out; ; i = (i + 1) & SEQ_MASK) {
+		if (!nd->nd_seq_wait[i]) {
+			nd->nd_seq_wait[i] = 0;
+			wake_up_interruptible(&nd->nd_seq_wque[i]);
+		}
+
+		if (i == nd->nd_seq_in)
+			break;
+	}
+
+	nd->nd_seq_out = nd->nd_seq_in;
+
+	nd->nd_unack = 0;
+	nd->nd_remain = 0;
+
+	nd->nd_tx_module = 0x10;
+	nd->nd_rx_module = 0x00;
+
+	for (i = 0, ch = nd->nd_chan; i < CHAN_MAX; i++, ch++) {
+		ch->ch_state = CS_IDLE;
+
+		ch->ch_otype = 0;
+		ch->ch_otype_waiting = 0;
+	}
+}
+
+/*
+ *  Increase the number of channels, waking up any
+ *  threads that might be waiting for the channels
+ *  to appear.
+ */
+static void increase_channel_count(struct nd_struct *nd, int n)
+{
+	struct ch_struct *ch;
+	struct device *classp;
+	char name[DEVICE_NAME_SIZE];
+	int ret;
+	u8 *buf;
+	int i;
+
+	for (i = nd->nd_chan_count; i < n; ++i) {
+		ch = nd->nd_chan + i;
+
+		/* FIXME: return a useful error instead! */
+		buf = kmalloc(TBUF_MAX, GFP_KERNEL);
+		if (!buf)
+			return;
+
+		if (ch->ch_tbuf)
+			pr_info_ratelimited("%s - ch_tbuf was not NULL\n",
+					    __func__);
+
+		ch->ch_tbuf = buf;
+
+		buf = kmalloc(RBUF_MAX, GFP_KERNEL);
+		if (!buf)
+			return;
+
+		if (ch->ch_rbuf)
+			pr_info("%s - ch_rbuf was not NULL\n",
+				__func__);
+		ch->ch_rbuf = buf;
+
+		classp = tty_port_register_device(&ch->port,
+						  nd->nd_serial_ttdriver, i,
+						  NULL);
+
+		ch->ch_tun.un_sysfs = classp;
+		snprintf(name, DEVICE_NAME_SIZE, "tty_%d", i);
+
+		dgrp_create_tty_sysfs(&ch->ch_tun, classp);
+		ret = sysfs_create_link(&nd->nd_class_dev->kobj,
+					&classp->kobj, name);
+
+		/* NOTE: We don't support "cu" devices anymore,
+		 * so you will notice we don't register them
+		 * here anymore. */
+		if (dgrp_register_prdevices) {
+			classp = tty_register_device(nd->nd_xprint_ttdriver,
+						     i, NULL);
+			ch->ch_pun.un_sysfs = classp;
+			snprintf(name, DEVICE_NAME_SIZE, "pr_%d", i);
+
+			dgrp_create_tty_sysfs(&ch->ch_pun, classp);
+			ret = sysfs_create_link(&nd->nd_class_dev->kobj,
+						&classp->kobj, name);
+		}
+
+		nd->nd_chan_count = i + 1;
+		wake_up_interruptible(&ch->ch_flag_wait);
+	}
+}
+
+/*
+ * Decrease the number of channels, and wake up any threads that might
+ * be waiting on the channels that vanished.
+ */
+static void decrease_channel_count(struct nd_struct *nd, int n)
+{
+	struct ch_struct *ch;
+	char name[DEVICE_NAME_SIZE];
+	int i;
+
+	for (i = nd->nd_chan_count - 1; i >= n; --i) {
+		ch = nd->nd_chan + i;
+
+		/*
+		 *  Make any open ports inoperative.
+		 */
+		ch->ch_state = CS_IDLE;
+
+		ch->ch_otype = 0;
+		ch->ch_otype_waiting = 0;
+
+		/*
+		 *  Only "HANGUP" if we care about carrier
+		 *  transitions and we are already open.
+		 */
+		if (ch->ch_open_count != 0) {
+			ch->ch_flag |= CH_HANGUP;
+			dgrp_carrier(ch);
+		}
+
+		/*
+		 * Unlike the CH_HANGUP flag above, use another
+		 * flag to indicate to the RealPort state machine
+		 * that this port has disappeared.
+		 */
+		if (ch->ch_open_count != 0)
+			ch->ch_flag |= CH_PORT_GONE;
+
+		wake_up_interruptible(&ch->ch_flag_wait);
+
+		nd->nd_chan_count = i;
+
+		kfree(ch->ch_tbuf);
+		ch->ch_tbuf = NULL;
+
+		kfree(ch->ch_rbuf);
+		ch->ch_rbuf = NULL;
+
+		nd->nd_chan_count = i;
+
+		dgrp_remove_tty_sysfs(ch->ch_tun.un_sysfs);
+		snprintf(name, DEVICE_NAME_SIZE, "tty_%d", i);
+		sysfs_remove_link(&nd->nd_class_dev->kobj, name);
+		tty_unregister_device(nd->nd_serial_ttdriver, i);
+
+		/*
+		 * NOTE: We don't support "cu" devices anymore, so don't
+		 * unregister them here anymore.
+		 */
+
+		if (dgrp_register_prdevices) {
+			dgrp_remove_tty_sysfs(ch->ch_pun.un_sysfs);
+			snprintf(name, DEVICE_NAME_SIZE, "pr_%d", i);
+			sysfs_remove_link(&nd->nd_class_dev->kobj, name);
+			tty_unregister_device(nd->nd_xprint_ttdriver, i);
+		}
+	}
+}
+
+/**
+ * dgrp_chan_count() -- Adjust the node channel count.
+ * @nd: pointer to a node structure
+ * @n: new value for channel count
+ *
+ * Adjusts the node channel count.  If new ports have appeared, it tries
+ * to signal those processes that might have been waiting for ports to
+ * appear.  If ports have disappeared it tries to signal those processes
+ * that might be hung waiting for a response for the now non-existant port.
+ */
+static void dgrp_chan_count(struct nd_struct *nd, int n)
+{
+	if (n == nd->nd_chan_count)
+		return;
+
+	if (n > nd->nd_chan_count)
+		increase_channel_count(nd, n);
+
+	if (n < nd->nd_chan_count)
+		decrease_channel_count(nd, n);
+}
+
+/**
+ * dgrp_monitor() -- send data to the device monitor queue
+ * @nd: pointer to a node structure
+ * @buf: data to copy to the monitoring buffer
+ * @len: number of bytes to transfer to the buffer
+ *
+ * Called by the net device routines to send data to the device
+ * monitor queue.  If the device monitor buffer is too full to
+ * accept the data, it waits until the buffer is ready.
+ */
+static void dgrp_monitor(struct nd_struct *nd, u8 *buf, int len)
+{
+	int n;
+	int r;
+	int rtn;
+
+	/*
+	 *  Grab monitor lock.
+	 */
+	down(&nd->nd_mon_semaphore);
+
+	/*
+	 *  Loop while data remains.
+	 */
+	while ((len > 0) && (nd->nd_mon_buf)) {
+		/*
+		 *  Determine the amount of available space left in the
+		 *  buffer.  If there's none, wait until some appears.
+		 */
+
+		n = (nd->nd_mon_out - nd->nd_mon_in - 1) & MON_MASK;
+
+		if (!n) {
+			nd->nd_mon_flag |= MON_WAIT_SPACE;
+
+			up(&nd->nd_mon_semaphore);
+
+			/*
+			 * Go to sleep waiting until the condition becomes true.
+			 */
+			rtn = wait_event_interruptible(nd->nd_mon_wqueue,
+						       ((nd->nd_mon_flag & MON_WAIT_SPACE) == 0));
+
+/* FIXME: really ignore rtn? */
+
+			/*
+			 *  We can't exit here if we receive a signal, since
+			 *  to do so would trash the debug stream.
+			 */
+
+			down(&nd->nd_mon_semaphore);
+
+			continue;
+		}
+
+		/*
+		 * Copy as much data as will fit.
+		 */
+
+		if (n > len)
+			n = len;
+
+		r = MON_MAX - nd->nd_mon_in;
+
+		if (r <= n) {
+			memcpy(nd->nd_mon_buf + nd->nd_mon_in, buf, r);
+
+			n -= r;
+
+			nd->nd_mon_in = 0;
+
+			buf += r;
+			len -= r;
+		}
+
+		memcpy(nd->nd_mon_buf + nd->nd_mon_in, buf, n);
+
+		nd->nd_mon_in += n;
+
+		buf += n;
+		len -= n;
+
+		if (nd->nd_mon_in >= MON_MAX)
+			pr_info_ratelimited("%s - nd_mon_in (%i) >= MON_MAX\n",
+					    __func__, nd->nd_mon_in);
+
+		/*
+		 *  Wakeup any thread waiting for data
+		 */
+
+		if (nd->nd_mon_flag & MON_WAIT_DATA) {
+			nd->nd_mon_flag &= ~MON_WAIT_DATA;
+			wake_up_interruptible(&nd->nd_mon_wqueue);
+		}
+	}
+
+	/*
+	 *  Release the monitor lock.
+	 */
+	up(&nd->nd_mon_semaphore);
+}
+
+/**
+ * dgrp_encode_time() -- Encodes rpdump time into a 4-byte quantity.
+ * @nd: pointer to a node structure
+ * @buf: destination buffer
+ *
+ * Encodes "rpdump" time into a 4-byte quantity.  Time is measured since
+ * open.
+ */
+static void dgrp_encode_time(struct nd_struct *nd, u8 *buf)
+{
+	ulong t;
+
+	/*
+	 *  Convert time in HZ since open to time in milliseconds
+	 *  since open.
+	 */
+	t = jiffies - nd->nd_mon_lbolt;
+	t = 1000 * (t / HZ) + 1000 * (t % HZ) / HZ;
+
+	put_unaligned_be32((uint)(t & 0xffffffff), buf);
+}
+
+
+
+/**
+ * dgrp_monitor_message() -- Builds a rpdump style message.
+ * @nd: pointer to a node structure
+ * @message: destination buffer
+ */
+static void dgrp_monitor_message(struct nd_struct *nd, char *message)
+{
+	u8 header[7];
+	int n;
+
+	header[0] = RPDUMP_MESSAGE;
+
+	dgrp_encode_time(nd, header + 1);
+
+	n = strlen(message);
+
+	put_unaligned_be16(n, header + 5);
+
+	dgrp_monitor(nd, header, sizeof(header));
+	dgrp_monitor(nd, (u8 *) message, n);
+}
+
+
+
+/**
+ * dgrp_monitor_reset() -- Note a reset in the monitoring buffer.
+ * @nd: pointer to a node structure
+ */
+static void dgrp_monitor_reset(struct nd_struct *nd)
+{
+	u8 header[5];
+
+	header[0] = RPDUMP_RESET;
+
+	dgrp_encode_time(nd, header + 1);
+
+	dgrp_monitor(nd, header, sizeof(header));
+}
+
+/**
+ * dgrp_monitor_data() -- builds a monitor data packet
+ * @nd: pointer to a node structure
+ * @type: type of message to be logged
+ * @buf: data to be logged
+ * @size: number of bytes in the buffer
+ */
+static void dgrp_monitor_data(struct nd_struct *nd, u8 type, u8 *buf, int size)
+{
+	u8 header[7];
+
+	header[0] = type;
+
+	dgrp_encode_time(nd, header + 1);
+
+	put_unaligned_be16(size, header + 5);
+
+	dgrp_monitor(nd, header, sizeof(header));
+	dgrp_monitor(nd, buf, size);
+}
+
+static int alloc_nd_buffers(struct nd_struct *nd)
+{
+
+	nd->nd_iobuf = NULL;
+	nd->nd_writebuf = NULL;
+	nd->nd_inputbuf = NULL;
+	nd->nd_inputflagbuf = NULL;
+
+	/*
+	 *  Allocate the network read/write buffer.
+	 */
+	nd->nd_iobuf = kzalloc(UIO_MAX + 10, GFP_KERNEL);
+	if (!nd->nd_iobuf)
+		goto out_err;
+
+	/*
+	 * Allocate a buffer for doing the copy from user space to
+	 * kernel space in the write routines.
+	 */
+	nd->nd_writebuf = kzalloc(WRITEBUFLEN, GFP_KERNEL);
+	if (!nd->nd_writebuf)
+		goto out_err;
+
+	/*
+	 * Allocate a buffer for doing the copy from kernel space to
+	 * tty buffer space in the read routines.
+	 */
+	nd->nd_inputbuf = kzalloc(MYFLIPLEN, GFP_KERNEL);
+	if (!nd->nd_inputbuf)
+		goto out_err;
+
+	/*
+	 * Allocate a buffer for doing the copy from kernel space to
+	 * tty buffer space in the read routines.
+	 */
+	nd->nd_inputflagbuf = kzalloc(MYFLIPLEN, GFP_KERNEL);
+	if (!nd->nd_inputflagbuf)
+		goto out_err;
+
+	return 0;
+
+out_err:
+	kfree(nd->nd_iobuf);
+	kfree(nd->nd_writebuf);
+	kfree(nd->nd_inputbuf);
+	kfree(nd->nd_inputflagbuf);
+	return -ENOMEM;
+}
+
+/*
+ * dgrp_net_open() -- Open the NET device for a particular PortServer
+ */
+static int dgrp_net_open(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+	struct proc_dir_entry *de;
+	ulong  lock_flags;
+	int rtn;
+
+	rtn = try_module_get(THIS_MODULE);
+	if (!rtn)
+		return -EAGAIN;
+
+	if (!capable(CAP_SYS_ADMIN)) {
+		rtn = -EPERM;
+		goto done;
+	}
+
+	/*
+	 *  Make sure that the "private_data" field hasn't already been used.
+	 */
+	if (file->private_data) {
+		rtn = -EINVAL;
+		goto done;
+	}
+
+	/*
+	 *  Get the node pointer, and fail if it doesn't exist.
+	 */
+	de = PDE(inode);
+	if (!de) {
+		rtn = -ENXIO;
+		goto done;
+	}
+
+	nd = (struct nd_struct *) de->data;
+	if (!nd) {
+		rtn = -ENXIO;
+		goto done;
+	}
+
+	file->private_data = (void *) nd;
+
+	/*
+	 *  Grab the NET lock.
+	 */
+	down(&nd->nd_net_semaphore);
+
+	if (nd->nd_state != NS_CLOSED) {
+		rtn = -EBUSY;
+		goto unlock;
+	}
+
+	/*
+	 *  Initialize the link speed parameters.
+	 */
+
+	nd->nd_link.lk_fast_rate = UIO_MAX;
+	nd->nd_link.lk_slow_rate = UIO_MAX;
+
+	nd->nd_link.lk_fast_delay = 1000;
+	nd->nd_link.lk_slow_delay = 1000;
+
+	nd->nd_link.lk_header_size = 46;
+
+
+	rtn = alloc_nd_buffers(nd);
+	if (rtn)
+		goto unlock;
+
+	/*
+	 *  The port is now open, so move it to the IDLE state
+	 */
+	dgrp_net_idle(nd);
+
+	nd->nd_tx_time = jiffies;
+
+	/*
+	 *  If the polling routing is not running, start it running here
+	 */
+	spin_lock_irqsave(&dgrp_poll_data.poll_lock, lock_flags);
+
+	if (!dgrp_poll_data.node_active_count) {
+		dgrp_poll_data.node_active_count = 2;
+		dgrp_poll_data.timer.expires = jiffies +
+			dgrp_poll_tick * HZ / 1000;
+		add_timer(&dgrp_poll_data.timer);
+	}
+
+	spin_unlock_irqrestore(&dgrp_poll_data.poll_lock, lock_flags);
+
+	dgrp_monitor_message(nd, "Net Open");
+
+unlock:
+	/*
+	 *  Release the NET lock.
+	 */
+	up(&nd->nd_net_semaphore);
+
+done:
+	if (rtn)
+		module_put(THIS_MODULE);
+
+	return rtn;
+}
+
+/* dgrp_net_release() -- close the NET device for a particular PortServer */
+static int dgrp_net_release(struct inode *inode, struct file *file)
+{
+	struct nd_struct *nd;
+	ulong  lock_flags;
+
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		goto done;
+
+/* TODO : historical locking placeholder */
+/*
+ *  In the HPUX version of the RealPort driver (which served as a basis
+ *  for this driver) this locking code was used.  Saved if ever we need
+ *  to review the locking under Linux.
+ */
+/*	spinlock(&nd->nd_lock); */
+
+
+	/*
+	 *  Grab the NET lock.
+	 */
+	down(&nd->nd_net_semaphore);
+
+	/*
+	 *  Before "closing" the internal connection, make sure all
+	 *  ports are "idle".
+	 */
+	dgrp_net_idle(nd);
+
+	nd->nd_state = NS_CLOSED;
+	nd->nd_flag = 0;
+
+	/*
+	 *  TODO ... must the wait queue be reset on close?
+	 *  should any pending waiters be reset?
+	 *  Let's decide to assert that the waitq is empty... and see
+	 *  how soon we break.
+	 */
+	if (waitqueue_active(&nd->nd_tx_waitq))
+		pr_info("%s - expected waitqueue_active to be false\n",
+			__func__);
+
+	nd->nd_send = 0;
+
+	kfree(nd->nd_iobuf);
+	nd->nd_iobuf = NULL;
+
+/* TODO : historical locking placeholder */
+/*
+ *  In the HPUX version of the RealPort driver (which served as a basis
+ *  for this driver) this locking code was used.  Saved if ever we need
+ *  to review the locking under Linux.
+ */
+/*	spinunlock( &nd->nd_lock ); */
+
+
+	kfree(nd->nd_writebuf);
+	nd->nd_writebuf = NULL;
+
+	kfree(nd->nd_inputbuf);
+	nd->nd_inputbuf = NULL;
+
+	kfree(nd->nd_inputflagbuf);
+	nd->nd_inputflagbuf = NULL;
+
+/* TODO : historical locking placeholder */
+/*
+ *  In the HPUX version of the RealPort driver (which served as a basis
+ *  for this driver) this locking code was used.  Saved if ever we need
+ *  to review the locking under Linux.
+ */
+/*	spinlock(&nd->nd_lock); */
+
+	/*
+	 *  Set the active port count to zero.
+	 */
+	dgrp_chan_count(nd, 0);
+
+/* TODO : historical locking placeholder */
+/*
+ *  In the HPUX version of the RealPort driver (which served as a basis
+ *  for this driver) this locking code was used.  Saved if ever we need
+ *  to review the locking under Linux.
+ */
+/*	spinunlock(&nd->nd_lock); */
+
+	/*
+	 *  Release the NET lock.
+	 */
+	up(&nd->nd_net_semaphore);
+
+	/*
+	 *  Cause the poller to stop scheduling itself if this is
+	 *  the last active node.
+	 */
+	spin_lock_irqsave(&dgrp_poll_data.poll_lock, lock_flags);
+
+	if (dgrp_poll_data.node_active_count == 2) {
+		del_timer(&dgrp_poll_data.timer);
+		dgrp_poll_data.node_active_count = 0;
+	}
+
+	spin_unlock_irqrestore(&dgrp_poll_data.poll_lock, lock_flags);
+
+done:
+	down(&nd->nd_net_semaphore);
+
+	dgrp_monitor_message(nd, "Net Close");
+
+	up(&nd->nd_net_semaphore);
+
+	module_put(THIS_MODULE);
+	file->private_data = NULL;
+	return 0;
+}
+
+/* used in dgrp_send to setup command header */
+static inline u8 *set_cmd_header(u8 *b, u8 port, u8 cmd)
+{
+	*b++ = 0xb0 + (port & 0x0f);
+	*b++ = cmd;
+	return b;
+}
+
+/**
+ * dgrp_send() -- build a packet for transmission to the server
+ * @nd: pointer to a node structure
+ * @tmax: maximum bytes to transmit
+ *
+ * returns number of bytes sent
+ */
+static int dgrp_send(struct nd_struct *nd, long tmax)
+{
+	struct ch_struct *ch = nd->nd_chan;
+	u8 *b;
+	u8 *buf;
+	u8 *mbuf;
+	u8 port;
+	int mod;
+	long send;
+	int maxport;
+	long lastport = -1;
+	ushort rwin;
+	long in;
+	ushort n;
+	long t;
+	long ttotal;
+	long tchan;
+	long tsend;
+	ushort tsafe;
+	long work;
+	long send_sync;
+	long wanted_sync_port = -1;
+	ushort tdata[CHAN_MAX];
+	long used_buffer;
+
+	mbuf = nd->nd_iobuf + UIO_BASE;
+	buf = b = mbuf;
+
+	send_sync = nd->nd_link.lk_slow_rate < UIO_MAX;
+
+	ttotal = 0;
+	tchan = 0;
+
+	memset(tdata, 0, sizeof(tdata));
+
+
+	/*
+	 * If there are any outstanding requests to be serviced,
+	 * service them here.
+	 */
+	if (nd->nd_send & NR_PASSWORD) {
+
+		/*
+		 *  Send Password response.
+		 */
+
+		b[0] = 0xfc;
+		b[1] = 0x20;
+		put_unaligned_be16(strlen(nd->password), b + 2);
+		b += 4;
+		b += strlen(nd->password);
+		nd->nd_send &= ~(NR_PASSWORD);
+	}
+
+
+	/*
+	 *  Loop over all modules to generate commands, and determine
+	 *  the amount of data queued for transmit.
+	 */
+
+	for (mod = 0, port = 0; port < nd->nd_chan_count; mod++) {
+		/*
+		 *  If this is not the current module, enter a module select
+		 *  code in the buffer.
+		 */
+
+		if (mod != nd->nd_tx_module)
+			mbuf = ++b;
+
+		/*
+		 *  Loop to process one module.
+		 */
+
+		maxport = port + 16;
+
+		if (maxport > nd->nd_chan_count)
+			maxport = nd->nd_chan_count;
+
+		for (; port < maxport; port++, ch++) {
+			/*
+			 *  Switch based on channel state.
+			 */
+
+			switch (ch->ch_state) {
+			/*
+			 *  Send requests when the port is closed, and there
+			 *  are no Open, Close or Cancel requests expected.
+			 */
+
+			case CS_IDLE:
+				/*
+				 * Wait until any open error code
+				 * has been delivered to all
+				 * associated ports.
+				 */
+
+				if (ch->ch_open_error) {
+					if (ch->ch_wait_count[ch->ch_otype]) {
+						work = 1;
+						break;
+					}
+
+					ch->ch_open_error = 0;
+				}
+
+				/*
+				 *  Wait until the channel HANGUP flag is reset
+				 *  before sending the first open.  We can only
+				 *  get to this state after a server disconnect.
+				 */
+
+				if ((ch->ch_flag & CH_HANGUP) != 0)
+					break;
+
+				/*
+				 *  If recovering from a TCP disconnect, or if
+				 *  there is an immediate open pending, send an
+				 *  Immediate Open request.
+				 */
+				if ((ch->ch_flag & CH_PORT_GONE) ||
+				    ch->ch_wait_count[OTYPE_IMMEDIATE] != 0) {
+					b = set_cmd_header(b, port, 10);
+					*b++ = 0;
+
+					ch->ch_state = CS_WAIT_OPEN;
+					ch->ch_otype = OTYPE_IMMEDIATE;
+					break;
+				}
+
+	/*
+	 *  If there is no Persistent or Incoming Open on the wait
+	 *  list in the server, and a thread is waiting for a
+	 *  Persistent or Incoming Open, send a Persistent or Incoming
+	 *  Open Request.
+	 */
+				if (ch->ch_otype_waiting == 0) {
+					if (ch->ch_wait_count[OTYPE_PERSISTENT] != 0) {
+						b = set_cmd_header(b, port, 10);
+						*b++ = 1;
+
+						ch->ch_state = CS_WAIT_OPEN;
+						ch->ch_otype = OTYPE_PERSISTENT;
+					} else if (ch->ch_wait_count[OTYPE_INCOMING] != 0) {
+						b = set_cmd_header(b, port, 10);
+						*b++ = 2;
+
+						ch->ch_state = CS_WAIT_OPEN;
+						ch->ch_otype = OTYPE_INCOMING;
+					}
+					break;
+				}
+
+				/*
+				 *  If a Persistent or Incoming Open is pending in
+				 *  the server, but there is no longer an open
+				 *  thread waiting for it, cancel the request.
+				 */
+
+				if (ch->ch_wait_count[ch->ch_otype_waiting] == 0) {
+					b = set_cmd_header(b, port, 10);
+					*b++ = 4;
+
+					ch->ch_state = CS_WAIT_CANCEL;
+					ch->ch_otype = ch->ch_otype_waiting;
+				}
+				break;
+
+				/*
+				 *  Send port parameter queries.
+				 */
+			case CS_SEND_QUERY:
+				/*
+				 *  Clear out all FEP state that might remain
+				 *  from the last connection.
+				 */
+
+				ch->ch_flag |= CH_PARAM;
+
+				ch->ch_flag &= ~CH_RX_FLUSH;
+
+				ch->ch_expect = 0;
+
+				ch->ch_s_tin   = 0;
+				ch->ch_s_tpos  = 0;
+				ch->ch_s_tsize = 0;
+				ch->ch_s_treq  = 0;
+				ch->ch_s_elast = 0;
+
+				ch->ch_s_rin   = 0;
+				ch->ch_s_rwin  = 0;
+				ch->ch_s_rsize = 0;
+
+				ch->ch_s_tmax  = 0;
+				ch->ch_s_ttime = 0;
+				ch->ch_s_rmax  = 0;
+				ch->ch_s_rtime = 0;
+				ch->ch_s_rlow  = 0;
+				ch->ch_s_rhigh = 0;
+
+				ch->ch_s_brate = 0;
+				ch->ch_s_iflag = 0;
+				ch->ch_s_cflag = 0;
+				ch->ch_s_oflag = 0;
+				ch->ch_s_xflag = 0;
+
+				ch->ch_s_mout  = 0;
+				ch->ch_s_mflow = 0;
+				ch->ch_s_mctrl = 0;
+				ch->ch_s_xon   = 0;
+				ch->ch_s_xoff  = 0;
+				ch->ch_s_lnext = 0;
+				ch->ch_s_xxon  = 0;
+				ch->ch_s_xxoff = 0;
+
+				/* Send Sequence Request */
+				b = set_cmd_header(b, port, 14);
+
+				/* Configure Event Conditions Packet */
+				b = set_cmd_header(b, port, 42);
+				put_unaligned_be16(0x02c0, b);
+				b += 2;
+				*b++ = (DM_DTR | DM_RTS | DM_CTS |
+					DM_DSR | DM_RI | DM_CD);
+
+				/* Send Status Request */
+				b = set_cmd_header(b, port, 16);
+
+				/* Send Buffer Request  */
+				b = set_cmd_header(b, port, 20);
+
+				/* Send Port Capability Request */
+				b = set_cmd_header(b, port, 22);
+
+				ch->ch_expect = (RR_SEQUENCE |
+						 RR_STATUS  |
+						 RR_BUFFER |
+						 RR_CAPABILITY);
+
+				ch->ch_state = CS_WAIT_QUERY;
+
+				/* Raise modem signals */
+				b = set_cmd_header(b, port, 44);
+
+				if (ch->ch_flag & CH_PORT_GONE)
+					ch->ch_s_mout = ch->ch_mout;
+				else
+					ch->ch_s_mout = ch->ch_mout = DM_DTR | DM_RTS;
+
+				*b++ = ch->ch_mout;
+				*b++ = ch->ch_s_mflow = 0;
+				*b++ = ch->ch_s_mctrl = ch->ch_mctrl = 0;
+
+				if (ch->ch_flag & CH_PORT_GONE)
+					ch->ch_flag &= ~CH_PORT_GONE;
+
+				break;
+
+			/*
+			 *  Handle normal open and ready mode.
+			 */
+
+			case CS_READY:
+
+				/*
+				 *  If the port is not open, and there are no
+				 *  no longer any ports requesting an open,
+				 *  then close the port.
+				 */
+
+				if (ch->ch_open_count == 0 &&
+				    ch->ch_wait_count[ch->ch_otype] == 0) {
+					goto send_close;
+				}
+
+	/*
+	 *  Process waiting input.
+	 *
+	 *  If there is no one to read it, discard the data.
+	 *
+	 *  Otherwise if we are not in fastcook mode, or if there is a
+	 *  fastcook thread waiting for data, send the data to the
+	 *  line discipline.
+	 */
+				if (ch->ch_rin != ch->ch_rout) {
+					if (ch->ch_tun.un_open_count == 0 ||
+					     (ch->ch_tun.un_flag & UN_CLOSING) ||
+					    (ch->ch_cflag & CF_CREAD) == 0) {
+						ch->ch_rout = ch->ch_rin;
+					} else if ((ch->ch_flag & CH_FAST_READ) == 0 ||
+							ch->ch_inwait != 0) {
+						dgrp_input(ch);
+
+						if (ch->ch_rin != ch->ch_rout)
+							work = 1;
+					}
+				}
+
+				/*
+				 *  Handle receive flush, and changes to
+				 *  server port parameters.
+				 */
+
+				if (ch->ch_flag & (CH_RX_FLUSH | CH_PARAM)) {
+				/*
+				 *  If we are in receive flush mode,
+				 *  and enough data has gone by, reset
+				 *  receive flush mode.
+				 */
+					if (ch->ch_flag & CH_RX_FLUSH) {
+						if (((ch->ch_flush_seq - nd->nd_seq_out) & SEQ_MASK) >
+						    ((nd->nd_seq_in - nd->nd_seq_out) & SEQ_MASK))
+							ch->ch_flag &= ~CH_RX_FLUSH;
+						else
+							work = 1;
+					}
+
+					/*
+					 *  Send TMAX, TTIME.
+					 */
+
+					if (ch->ch_s_tmax  != ch->ch_tmax ||
+					    ch->ch_s_ttime != ch->ch_ttime) {
+						b = set_cmd_header(b, port, 48);
+
+						ch->ch_s_tmax = ch->ch_tmax;
+						ch->ch_s_ttime = ch->ch_ttime;
+
+						put_unaligned_be16(ch->ch_s_tmax,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_ttime,
+								   b);
+						b += 2;
+					}
+
+					/*
+					 *  Send RLOW, RHIGH.
+					 */
+
+					if (ch->ch_s_rlow  != ch->ch_rlow ||
+					    ch->ch_s_rhigh != ch->ch_rhigh) {
+						b = set_cmd_header(b, port, 45);
+
+						ch->ch_s_rlow  = ch->ch_rlow;
+						ch->ch_s_rhigh = ch->ch_rhigh;
+
+						put_unaligned_be16(ch->ch_s_rlow,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_rhigh,
+								   b);
+						b += 2;
+					}
+
+					/*
+					 *  Send BRATE, CFLAG, IFLAG,
+					 *  OFLAG, XFLAG.
+					 */
+
+					if (ch->ch_s_brate != ch->ch_brate ||
+					    ch->ch_s_cflag != ch->ch_cflag ||
+					    ch->ch_s_iflag != ch->ch_iflag ||
+					    ch->ch_s_oflag != ch->ch_oflag ||
+					    ch->ch_s_xflag != ch->ch_xflag) {
+						b = set_cmd_header(b, port, 40);
+
+						ch->ch_s_brate = ch->ch_brate;
+						ch->ch_s_cflag = ch->ch_cflag;
+						ch->ch_s_iflag = ch->ch_iflag;
+						ch->ch_s_oflag = ch->ch_oflag;
+						ch->ch_s_xflag = ch->ch_xflag;
+
+						put_unaligned_be16(ch->ch_s_brate,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_cflag,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_iflag,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_oflag,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_xflag,
+								   b);
+						b += 2;
+					}
+
+					/*
+					 *  Send MOUT, MFLOW, MCTRL.
+					 */
+
+					if (ch->ch_s_mout  != ch->ch_mout  ||
+					    ch->ch_s_mflow != ch->ch_mflow ||
+					    ch->ch_s_mctrl != ch->ch_mctrl) {
+						b = set_cmd_header(b, port, 44);
+
+						*b++ = ch->ch_s_mout  = ch->ch_mout;
+						*b++ = ch->ch_s_mflow = ch->ch_mflow;
+						*b++ = ch->ch_s_mctrl = ch->ch_mctrl;
+					}
+
+					/*
+					 *  Send Flow control characters.
+					 */
+
+					if (ch->ch_s_xon   != ch->ch_xon   ||
+					    ch->ch_s_xoff  != ch->ch_xoff  ||
+					    ch->ch_s_lnext != ch->ch_lnext ||
+					    ch->ch_s_xxon  != ch->ch_xxon  ||
+					    ch->ch_s_xxoff != ch->ch_xxoff) {
+						b = set_cmd_header(b, port, 46);
+
+						*b++ = ch->ch_s_xon   = ch->ch_xon;
+						*b++ = ch->ch_s_xoff  = ch->ch_xoff;
+						*b++ = ch->ch_s_lnext = ch->ch_lnext;
+						*b++ = ch->ch_s_xxon  = ch->ch_xxon;
+						*b++ = ch->ch_s_xxoff = ch->ch_xxoff;
+					}
+
+					/*
+					 *  Send RMAX, RTIME.
+					 */
+
+					if (ch->ch_s_rmax != ch->ch_rmax ||
+					    ch->ch_s_rtime != ch->ch_rtime) {
+						b = set_cmd_header(b, port, 47);
+
+						ch->ch_s_rmax  = ch->ch_rmax;
+						ch->ch_s_rtime = ch->ch_rtime;
+
+						put_unaligned_be16(ch->ch_s_rmax,
+								   b);
+						b += 2;
+
+						put_unaligned_be16(ch->ch_s_rtime,
+								   b);
+						b += 2;
+					}
+
+					ch->ch_flag &= ~CH_PARAM;
+					wake_up_interruptible(&ch->ch_flag_wait);
+				}
+
+
+				/*
+				 *  Handle action commands.
+				 */
+
+				if (ch->ch_send != 0) {
+					/* int send = ch->ch_send & ~ch->ch_expect; */
+					send = ch->ch_send & ~ch->ch_expect;
+
+					/* Send character immediate */
+					if ((send & RR_TX_ICHAR) != 0) {
+						b = set_cmd_header(b, port, 60);
+
+						*b++ = ch->ch_xon;
+						ch->ch_expect |= RR_TX_ICHAR;
+					}
+
+					/* BREAK request */
+					if ((send & RR_TX_BREAK) != 0) {
+						if (ch->ch_break_time != 0) {
+							b = set_cmd_header(b, port, 61);
+							put_unaligned_be16(ch->ch_break_time,
+									   b);
+							b += 2;
+
+							ch->ch_expect |= RR_TX_BREAK;
+							ch->ch_break_time = 0;
+						} else {
+							ch->ch_send &= ~RR_TX_BREAK;
+							ch->ch_flag &= ~CH_TX_BREAK;
+							wake_up_interruptible(&ch->ch_flag_wait);
+						}
+					}
+
+					/*
+					 *  Flush input/output buffers.
+					 */
+
+					if ((send & (RR_RX_FLUSH | RR_TX_FLUSH)) != 0) {
+						b = set_cmd_header(b, port, 62);
+
+						*b++ = ((send & RR_TX_FLUSH) == 0 ? 1 :
+							(send & RR_RX_FLUSH) == 0 ? 2 : 3);
+
+						if (send & RR_RX_FLUSH) {
+							ch->ch_flush_seq = nd->nd_seq_in;
+							ch->ch_flag |= CH_RX_FLUSH;
+							work = 1;
+							send_sync = 1;
+							wanted_sync_port = port;
+						}
+
+						ch->ch_send &= ~(RR_RX_FLUSH | RR_TX_FLUSH);
+					}
+
+					/*  Pause input/output */
+					if ((send & (RR_RX_STOP | RR_TX_STOP)) != 0) {
+						b = set_cmd_header(b, port, 63);
+						*b = 0;
+
+						if ((send & RR_TX_STOP) != 0)
+							*b |= EV_OPU;
+
+						if ((send & RR_RX_STOP) != 0)
+							*b |= EV_IPU;
+
+						b++;
+
+						ch->ch_send &= ~(RR_RX_STOP | RR_TX_STOP);
+					}
+
+					/* Start input/output */
+					if ((send & (RR_RX_START | RR_TX_START)) != 0) {
+						b = set_cmd_header(b, port, 64);
+						*b = 0;
+
+						if ((send & RR_TX_START) != 0)
+							*b |= EV_OPU | EV_OPS | EV_OPX;
+
+						if ((send & RR_RX_START) != 0)
+							*b |= EV_IPU | EV_IPS;
+
+						b++;
+
+						ch->ch_send &= ~(RR_RX_START | RR_TX_START);
+					}
+				}
+
+
+				/*
+				 *  Send a window sequence to acknowledge received data.
+				 */
+
+				rwin = (ch->ch_s_rin +
+					((ch->ch_rout - ch->ch_rin - 1) & RBUF_MASK));
+
+				n = (rwin - ch->ch_s_rwin) & 0xffff;
+
+				if (n >= RBUF_MAX / 4) {
+					b[0] = 0xa0 + (port & 0xf);
+					ch->ch_s_rwin = rwin;
+					put_unaligned_be16(rwin, b + 1);
+					b += 3;
+				}
+
+				/*
+				 *  If the terminal is waiting on LOW
+				 *  water or EMPTY, and the condition
+				 *  is now satisfied, call the line
+				 *  discipline to put more data in the
+				 *  buffer.
+				 */
+
+				n = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+
+				if ((ch->ch_tun.un_flag & (UN_EMPTY|UN_LOW)) != 0) {
+					if ((ch->ch_tun.un_flag & UN_LOW) != 0 ?
+					    (n <= TBUF_LOW) :
+					    (n == 0 && ch->ch_s_tpos == ch->ch_s_tin)) {
+						ch->ch_tun.un_flag &= ~(UN_EMPTY|UN_LOW);
+
+						if (waitqueue_active(&((ch->ch_tun.un_tty)->write_wait)))
+							wake_up_interruptible(&((ch->ch_tun.un_tty)->write_wait));
+						tty_wakeup(ch->ch_tun.un_tty);
+						n = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+					}
+				}
+
+				/*
+				 * If the printer is waiting on LOW
+				 * water, TIME, EMPTY or PWAIT, and is
+				 * now ready to put more data in the
+				 * buffer, call the line discipline to
+				 * do the job.
+				 */
+
+				if (ch->ch_pun.un_open_count &&
+				    (ch->ch_pun.un_flag &
+				    (UN_EMPTY|UN_TIME|UN_LOW|UN_PWAIT)) != 0) {
+
+					if ((ch->ch_pun.un_flag & UN_LOW) != 0 ?
+					    (n <= TBUF_LOW) :
+					    (ch->ch_pun.un_flag & UN_TIME) != 0 ?
+					    ((jiffies - ch->ch_waketime) >= 0) :
+					    (n == 0 && ch->ch_s_tpos == ch->ch_s_tin) &&
+					    ((ch->ch_pun.un_flag & UN_EMPTY) != 0 ||
+					    ((ch->ch_tun.un_open_count &&
+					      ch->ch_tun.un_tty->ops->chars_in_buffer) ?
+					     (ch->ch_tun.un_tty->ops->chars_in_buffer)(ch->ch_tun.un_tty) == 0
+					     : 1
+					    )
+					    )) {
+						ch->ch_pun.un_flag &= ~(UN_EMPTY | UN_TIME | UN_LOW | UN_PWAIT);
+
+						if (waitqueue_active(&((ch->ch_pun.un_tty)->write_wait)))
+							wake_up_interruptible(&((ch->ch_pun.un_tty)->write_wait));
+						tty_wakeup(ch->ch_pun.un_tty);
+						n = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+
+					} else if ((ch->ch_pun.un_flag & UN_TIME) != 0) {
+						work = 1;
+					}
+				}
+
+
+				/*
+				 *  Determine the max number of bytes
+				 *  this port can send, including
+				 *  packet header overhead.
+				 */
+
+				t = ((ch->ch_s_tsize + ch->ch_s_tpos - ch->ch_s_tin) & 0xffff);
+
+				if (n > t)
+					n = t;
+
+				if (n != 0) {
+					n += (n <= 8 ? 1 : n <= 255 ? 2 : 3);
+
+					tdata[tchan++] = n;
+					ttotal += n;
+				}
+				break;
+
+			/*
+			 *  Close the port.
+			 */
+
+send_close:
+			case CS_SEND_CLOSE:
+				b = set_cmd_header(b, port, 10);
+				if (ch->ch_otype == OTYPE_IMMEDIATE)
+					*b++ = 3;
+				else
+					*b++ = 4;
+
+				ch->ch_state = CS_WAIT_CLOSE;
+				break;
+
+			/*
+			 *  Wait for a previous server request.
+			 */
+
+			case CS_WAIT_OPEN:
+			case CS_WAIT_CANCEL:
+			case CS_WAIT_FAIL:
+			case CS_WAIT_QUERY:
+			case CS_WAIT_CLOSE:
+				break;
+
+			default:
+				pr_info("%s - unexpected channel state (%i)\n",
+					__func__, ch->ch_state);
+			}
+		}
+
+		/*
+		 *  If a module select code is needed, drop one in.  If space
+		 *  was reserved for one, but none is needed, recover the space.
+		 */
+
+		if (mod != nd->nd_tx_module) {
+			if (b != mbuf) {
+				mbuf[-1] = 0xf0 | mod;
+				nd->nd_tx_module = mod;
+			} else {
+				b--;
+			}
+		}
+	}
+
+	/*
+	 *  Adjust "tmax" so that under worst case conditions we do
+	 *  not overflow either the daemon buffer or the internal
+	 *  buffer in the loop that follows.   Leave a safe area
+	 *  of 64 bytes so we start getting asserts before we start
+	 *  losing data or clobbering memory.
+	 */
+
+	n = UIO_MAX - UIO_BASE;
+
+	if (tmax > n)
+		tmax = n;
+
+	tmax -= 64;
+
+	tsafe = tmax;
+
+	/*
+	 *  Allocate space for 5 Module Selects, 1 Sequence Request,
+	 *  and 1 Set TREQ for each active channel.
+	 */
+
+	tmax -= 5 + 3 + 4 * nd->nd_chan_count;
+
+	/*
+	 *  Further reduce "tmax" to the available transmit credit.
+	 *  Note that this is a soft constraint;  The transmit credit
+	 *  can go negative for a time and then recover.
+	 */
+
+	n = nd->nd_tx_deposit - nd->nd_tx_charge - nd->nd_link.lk_header_size;
+
+	if (tmax > n)
+		tmax = n;
+
+	/*
+	 *  Finally reduce tmax by the number of bytes already in
+	 *  the buffer.
+	 */
+
+	tmax -= b - buf;
+
+	/*
+	 *  Suspend data transmit unless every ready channel can send
+	 *  at least 1 character.
+	 */
+	if (tmax < 2 * nd->nd_chan_count) {
+		tsend = 1;
+
+	} else if (tchan > 1 && ttotal > tmax) {
+
+		/*
+		 *  If transmit is limited by the credit budget, find the
+		 *  largest number of characters we can send without driving
+		 *  the credit negative.
+		 */
+
+		long tm = tmax;
+		int tc = tchan;
+		int try;
+
+		tsend = tm / tc;
+
+		for (try = 0; try < 3; try++) {
+			int i;
+			int c = 0;
+
+			for (i = 0; i < tc; i++) {
+				if (tsend < tdata[i])
+					tdata[c++] = tdata[i];
+				else
+					tm -= tdata[i];
+			}
+
+			if (c == tc)
+				break;
+
+			tsend = tm / c;
+
+			if (c == 1)
+				break;
+
+			tc = c;
+		}
+
+		tsend = tm / nd->nd_chan_count;
+
+		if (tsend < 2)
+			tsend = 1;
+
+	} else {
+		/*
+		 *  If no budgetary constraints, or only one channel ready
+		 *  to send, set the character limit to the remaining
+		 *  buffer size.
+		 */
+
+		tsend = tmax;
+	}
+
+	tsend -= (tsend <= 9) ? 1 : (tsend <= 257) ? 2 : 3;
+
+	/*
+	 *  Loop over all channels, sending queued data.
+	 */
+
+	port = 0;
+	ch = nd->nd_chan;
+	used_buffer = tmax;
+
+	for (mod = 0; port < nd->nd_chan_count; mod++) {
+		/*
+		 *  If this is not the current module, enter a module select
+		 *  code in the buffer.
+		 */
+
+		if (mod != nd->nd_tx_module)
+			mbuf = ++b;
+
+		/*
+		 *  Loop to process one module.
+		 */
+
+		maxport = port + 16;
+
+		if (maxport > nd->nd_chan_count)
+			maxport = nd->nd_chan_count;
+
+		for (; port < maxport; port++, ch++) {
+			if (ch->ch_state != CS_READY)
+				continue;
+
+			lastport = port;
+
+			n = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+
+			/*
+			 *  If there is data that can be sent, send it.
+			 */
+
+			if (n != 0 && used_buffer > 0) {
+				t = (ch->ch_s_tsize + ch->ch_s_tpos - ch->ch_s_tin) & 0xffff;
+
+				if (n > t)
+					n = t;
+
+				if (n > tsend) {
+					work = 1;
+					n = tsend;
+				}
+
+				if (n > used_buffer) {
+					work = 1;
+					n = used_buffer;
+				}
+
+				if (n <= 0)
+					continue;
+
+				/*
+				 *  Create the correct size transmit header,
+				 *  depending on the amount of data to transmit.
+				 */
+
+				if (n <= 8) {
+
+					b[0] = ((n - 1) << 4) + (port & 0xf);
+					b += 1;
+
+				} else if (n <= 255) {
+
+					b[0] = 0x80 + (port & 0xf);
+					b[1] = n;
+					b += 2;
+
+				} else {
+
+					b[0] = 0x90 + (port & 0xf);
+					put_unaligned_be16(n, b + 1);
+					b += 3;
+				}
+
+				ch->ch_s_tin = (ch->ch_s_tin + n) & 0xffff;
+
+				/*
+				 *  Copy transmit data to the packet.
+				 */
+
+				t = TBUF_MAX - ch->ch_tout;
+
+				if (n >= t) {
+					memcpy(b, ch->ch_tbuf + ch->ch_tout, t);
+					b += t;
+					n -= t;
+					used_buffer -= t;
+					ch->ch_tout = 0;
+				}
+
+				memcpy(b, ch->ch_tbuf + ch->ch_tout, n);
+				b += n;
+				used_buffer -= n;
+				ch->ch_tout += n;
+				n = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+			}
+
+			/*
+			 *  Wake any terminal unit process waiting in the
+			 *  dgrp_write routine for low water.
+			 */
+
+			if (n > TBUF_LOW)
+				continue;
+
+			if ((ch->ch_flag & CH_LOW) != 0) {
+				ch->ch_flag &= ~CH_LOW;
+				wake_up_interruptible(&ch->ch_flag_wait);
+			}
+
+			/* selwakeup tty_sel */
+			if (ch->ch_tun.un_open_count) {
+				struct tty_struct *tty = (ch->ch_tun.un_tty);
+
+				if (waitqueue_active(&tty->write_wait))
+					wake_up_interruptible(&tty->write_wait);
+
+				tty_wakeup(tty);
+			}
+
+			if (ch->ch_pun.un_open_count) {
+				struct tty_struct *tty = (ch->ch_pun.un_tty);
+
+				if (waitqueue_active(&tty->write_wait))
+					wake_up_interruptible(&tty->write_wait);
+
+				tty_wakeup(tty);
+			}
+
+			/*
+			 *  Do EMPTY processing.
+			 */
+
+			if (n != 0)
+				continue;
+
+			if ((ch->ch_flag & (CH_EMPTY | CH_DRAIN)) != 0 ||
+			    (ch->ch_pun.un_flag & UN_EMPTY) != 0) {
+				/*
+				 *  If there is still data in the server, ask the server
+				 *  to notify us when its all gone.
+				 */
+
+				if (ch->ch_s_treq != ch->ch_s_tin) {
+					b = set_cmd_header(b, port, 43);
+
+					ch->ch_s_treq = ch->ch_s_tin;
+					put_unaligned_be16(ch->ch_s_treq,
+							   b);
+					b += 2;
+				}
+
+				/*
+				 *  If there is a thread waiting for buffer empty,
+				 *  and we are truly empty, wake the thread.
+				 */
+
+				else if ((ch->ch_flag & CH_EMPTY) != 0 &&
+					(ch->ch_send & RR_TX_BREAK) == 0) {
+					ch->ch_flag &= ~CH_EMPTY;
+
+					wake_up_interruptible(&ch->ch_flag_wait);
+				}
+			}
+		}
+
+		/*
+		 *  If a module select code is needed, drop one in.  If space
+		 *  was reserved for one, but none is needed, recover the space.
+		 */
+
+		if (mod != nd->nd_tx_module) {
+			if (b != mbuf) {
+				mbuf[-1] = 0xf0 | mod;
+				nd->nd_tx_module = mod;
+			} else {
+				b--;
+			}
+		}
+	}
+
+	/*
+	 *  Send a synchronization sequence associated with the last open
+	 *  channel that sent data, and remember the time when the data was
+	 *  sent.
+	 */
+
+	in = nd->nd_seq_in;
+
+	if ((send_sync || nd->nd_seq_wait[in] != 0) && lastport >= 0) {
+		u8 *bb = b;
+
+		/*
+		 * Attempt the use the port that really wanted the sync.
+		 * This gets around a race condition where the "lastport" is in
+		 * the middle of the close() routine, and by the time we
+		 * send this command, it will have already acked the close, and
+		 * thus not send the sync response.
+		 */
+		if (wanted_sync_port >= 0)
+			lastport = wanted_sync_port;
+		/*
+		 * Set a flag just in case the port is in the middle of a close,
+		 * it will not be permitted to actually close until we get an
+		 * sync response, and clear the flag there.
+		 */
+		ch = nd->nd_chan + lastport;
+		ch->ch_flag |= CH_WAITING_SYNC;
+
+		mod = lastport >> 4;
+
+		if (mod != nd->nd_tx_module) {
+			bb[0] = 0xf0 + mod;
+			bb += 1;
+
+			nd->nd_tx_module = mod;
+		}
+
+		bb = set_cmd_header(bb, lastport, 12);
+		*bb++ = in;
+
+		nd->nd_seq_size[in] = bb - buf;
+		nd->nd_seq_time[in] = jiffies;
+
+		if (++in >= SEQ_MAX)
+			in = 0;
+
+		if (in != nd->nd_seq_out) {
+			b = bb;
+			nd->nd_seq_in = in;
+			nd->nd_unack += b - buf;
+		}
+	}
+
+	/*
+	 *  If there are no open ports, a sync cannot be sent.
+	 *  There is nothing left to wait for anyway, so wake any
+	 *  thread waiting for an acknowledgement.
+	 */
+
+	else if (nd->nd_seq_wait[in] != 0) {
+		nd->nd_seq_wait[in] = 0;
+
+		wake_up_interruptible(&nd->nd_seq_wque[in]);
+	}
+
+	/*
+	 *  If there is no traffic for an interval of IDLE_MAX, then
+	 *  send a single byte packet.
+	 */
+
+	if (b != buf) {
+		nd->nd_tx_time = jiffies;
+	} else if ((ulong)(jiffies - nd->nd_tx_time) >= IDLE_MAX) {
+		*b++ = 0xf0 | nd->nd_tx_module;
+		nd->nd_tx_time = jiffies;
+	}
+
+	n = b - buf;
+
+	if (n >= tsafe)
+		pr_info("%s - n(%i) >= tsafe(%i)\n",
+			__func__, n, tsafe);
+
+	if (tsend < 0)
+		dgrp_dump(buf, n);
+
+	nd->nd_tx_work = work;
+
+	return n;
+}
+
+/*
+ * dgrp_net_read()
+ * Data to be sent TO the PortServer from the "async." half of the driver.
+ */
+static ssize_t dgrp_net_read(struct file *file, char __user *buf, size_t count,
+			     loff_t *ppos)
+{
+	struct nd_struct *nd;
+	long n;
+	u8 *local_buf;
+	u8 *b;
+	ssize_t rtn;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		return -ENXIO;
+
+	if (count < UIO_MIN)
+		return -EINVAL;
+
+	/*
+	 *  Only one read/write operation may be in progress at
+	 *  any given time.
+	 */
+
+	/*
+	 *  Grab the NET lock.
+	 */
+	down(&nd->nd_net_semaphore);
+
+	nd->nd_read_count++;
+
+	nd->nd_tx_ready = 0;
+
+	/*
+	 *  Determine the effective size of the buffer.
+	 */
+
+	if (nd->nd_remain > UIO_BASE)
+		pr_info_ratelimited("%s - nd_remain(%i) > UIO_BASE\n",
+				    __func__, nd->nd_remain);
+
+	b = local_buf = nd->nd_iobuf + UIO_BASE;
+
+	/*
+	 *  Generate data according to the node state.
+	 */
+
+	switch (nd->nd_state) {
+	/*
+	 *  Initialize the connection.
+	 */
+
+	case NS_IDLE:
+		if (nd->nd_mon_buf)
+			dgrp_monitor_reset(nd);
+
+		/*
+		 *  Request a Product ID Packet.
+		 */
+
+		b[0] = 0xfb;
+		b[1] = 0x01;
+		b += 2;
+
+		nd->nd_expect |= NR_IDENT;
+
+		/*
+		 *  Request a Server Capability ID Response.
+		 */
+
+		b[0] = 0xfb;
+		b[1] = 0x02;
+		b += 2;
+
+		nd->nd_expect |= NR_CAPABILITY;
+
+		/*
+		 *  Request a Server VPD Response.
+		 */
+
+		b[0] = 0xfb;
+		b[1] = 0x18;
+		b += 2;
+
+		nd->nd_expect |= NR_VPD;
+
+		nd->nd_state = NS_WAIT_QUERY;
+		break;
+
+	/*
+	 *  We do serious communication with the server only in
+	 *  the READY state.
+	 */
+
+	case NS_READY:
+		b = dgrp_send(nd, count) + local_buf;
+		break;
+
+	/*
+	 *  Send off an error after receiving a bogus message
+	 *  from the server.
+	 */
+
+	case NS_SEND_ERROR:
+		n = strlen(nd->nd_error);
+
+		b[0] = 0xff;
+		b[1] = n;
+		memcpy(b + 2, nd->nd_error, n);
+		b += 2 + n;
+
+		dgrp_net_idle(nd);
+		/*
+		 *  Set the active port count to zero.
+		 */
+		dgrp_chan_count(nd, 0);
+		break;
+
+	default:
+		break;
+	}
+
+	n = b - local_buf;
+
+	if (n != 0) {
+		nd->nd_send_count++;
+
+		nd->nd_tx_byte   += n + nd->nd_link.lk_header_size;
+		nd->nd_tx_charge += n + nd->nd_link.lk_header_size;
+	}
+
+	rtn = copy_to_user((void __user *)buf, local_buf, n);
+	if (rtn) {
+		rtn = -EFAULT;
+		goto done;
+	}
+
+	*ppos += n;
+
+	rtn = n;
+
+	if (nd->nd_mon_buf)
+		dgrp_monitor_data(nd, RPDUMP_CLIENT, local_buf, n);
+
+	/*
+	 *  Release the NET lock.
+	 */
+done:
+	up(&nd->nd_net_semaphore);
+
+	return rtn;
+}
+
+/**
+ * dgrp_receive() -- decode data packets received from the remote PortServer.
+ * @nd: pointer to a node structure
+ */
+static void dgrp_receive(struct nd_struct *nd)
+{
+	struct ch_struct *ch;
+	u8 *buf;
+	u8 *b;
+	u8 *dbuf;
+	char *error;
+	long port;
+	long dlen;
+	long plen;
+	long remain;
+	long n;
+	long mlast;
+	long elast;
+	long mstat;
+	long estat;
+
+	char ID[3];
+
+	nd->nd_tx_time = jiffies;
+
+	ID_TO_CHAR(nd->nd_ID, ID);
+
+	b = buf = nd->nd_iobuf;
+	remain = nd->nd_remain;
+
+	/*
+	 *  Loop to process Realport protocol packets.
+	 */
+
+	while (remain > 0) {
+		int n0 = b[0] >> 4;
+		int n1 = b[0] & 0x0f;
+
+		if (n0 <= 12) {
+			port = (nd->nd_rx_module << 4) + n1;
+
+			if (port >= nd->nd_chan_count) {
+				error = "Improper Port Number";
+				goto prot_error;
+			}
+
+			ch = nd->nd_chan + port;
+		} else {
+			port = -1;
+			ch = NULL;
+		}
+
+		/*
+		 *  Process by major packet type.
+		 */
+
+		switch (n0) {
+
+		/*
+		 *  Process 1-byte header data packet.
+		 */
+
+		case 0:
+		case 1:
+		case 2:
+		case 3:
+		case 4:
+		case 5:
+		case 6:
+		case 7:
+			dlen = n0 + 1;
+			plen = dlen + 1;
+
+			dbuf = b + 1;
+			goto data;
+
+		/*
+		 *  Process 2-byte header data packet.
+		 */
+
+		case 8:
+			if (remain < 3)
+				goto done;
+
+			dlen = b[1];
+			plen = dlen + 2;
+
+			dbuf = b + 2;
+			goto data;
+
+		/*
+		 *  Process 3-byte header data packet.
+		 */
+
+		case 9:
+			if (remain < 4)
+				goto done;
+
+			dlen = get_unaligned_be16(b + 1);
+			plen = dlen + 3;
+
+			dbuf = b + 3;
+
+		/*
+		 *  Common packet handling code.
+		 */
+
+data:
+			nd->nd_tx_work = 1;
+
+			/*
+			 *  Otherwise data should appear only when we are
+			 *  in the CS_READY state.
+			 */
+
+			if (ch->ch_state < CS_READY) {
+				error = "Data received before RWIN established";
+				goto prot_error;
+			}
+
+			/*
+			 *  Assure that the data received is within the
+			 *  allowable window.
+			 */
+
+			n = (ch->ch_s_rwin - ch->ch_s_rin) & 0xffff;
+
+			if (dlen > n) {
+				error = "Receive data overrun";
+				goto prot_error;
+			}
+
+			/*
+			 *  If we received 3 or less characters,
+			 *  assume it is a human typing, and set RTIME
+			 *  to 10 milliseconds.
+			 *
+			 *  If we receive 10 or more characters,
+			 *  assume its not a human typing, and set RTIME
+			 *  to 100 milliseconds.
+			 */
+
+			if (ch->ch_edelay != DGRP_RTIME) {
+				if (ch->ch_rtime != ch->ch_edelay) {
+					ch->ch_rtime = ch->ch_edelay;
+					ch->ch_flag |= CH_PARAM;
+				}
+			} else if (dlen <= 3) {
+				if (ch->ch_rtime != 10) {
+					ch->ch_rtime = 10;
+					ch->ch_flag |= CH_PARAM;
+				}
+			} else {
+				if (ch->ch_rtime != DGRP_RTIME) {
+					ch->ch_rtime = DGRP_RTIME;
+					ch->ch_flag |= CH_PARAM;
+				}
+			}
+
+			/*
+			 *  If a portion of the packet is outside the
+			 *  buffer, shorten the effective length of the
+			 *  data packet to be the amount of data received.
+			 */
+
+			if (remain < plen)
+				dlen -= plen - remain;
+
+			/*
+			 *  Detect if receive flush is now complete.
+			 */
+
+			if ((ch->ch_flag & CH_RX_FLUSH) != 0 &&
+			    ((ch->ch_flush_seq - nd->nd_seq_out) & SEQ_MASK) >=
+			    ((nd->nd_seq_in    - nd->nd_seq_out) & SEQ_MASK)) {
+				ch->ch_flag &= ~CH_RX_FLUSH;
+			}
+
+			/*
+			 *  If we are ready to receive, move the data into
+			 *  the receive buffer.
+			 */
+
+			ch->ch_s_rin = (ch->ch_s_rin + dlen) & 0xffff;
+
+			if (ch->ch_state == CS_READY &&
+			    (ch->ch_tun.un_open_count != 0) &&
+			    (ch->ch_tun.un_flag & UN_CLOSING) == 0 &&
+			    (ch->ch_cflag & CF_CREAD) != 0 &&
+			    (ch->ch_flag & (CH_BAUD0 | CH_RX_FLUSH)) == 0 &&
+			    (ch->ch_send & RR_RX_FLUSH) == 0) {
+
+				if (ch->ch_rin + dlen >= RBUF_MAX) {
+					n = RBUF_MAX - ch->ch_rin;
+
+					memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, n);
+
+					ch->ch_rin = 0;
+					dbuf += n;
+					dlen -= n;
+				}
+
+				memcpy(ch->ch_rbuf + ch->ch_rin, dbuf, dlen);
+
+				ch->ch_rin += dlen;
+
+
+				/*
+				 *  If we are not in fastcook mode, or
+				 *  if there is a fastcook thread
+				 *  waiting for data, send the data to
+				 *  the line discipline.
+				 */
+
+				if ((ch->ch_flag & CH_FAST_READ) == 0 ||
+				    ch->ch_inwait != 0) {
+					dgrp_input(ch);
+				}
+
+				/*
+				 *  If there is a read thread waiting
+				 *  in select, and we are in fastcook
+				 *  mode, wake him up.
+				 */
+
+				if (waitqueue_active(&ch->ch_tun.un_tty->read_wait) &&
+				    (ch->ch_flag & CH_FAST_READ) != 0)
+					wake_up_interruptible(&ch->ch_tun.un_tty->read_wait);
+
+				/*
+				 * Wake any thread waiting in the
+				 * fastcook loop.
+				 */
+
+				if ((ch->ch_flag & CH_INPUT) != 0) {
+					ch->ch_flag &= ~CH_INPUT;
+
+					wake_up_interruptible(&ch->ch_flag_wait);
+				}
+			}
+
+			/*
+			 *  Fabricate and insert a data packet header to
+			 *  preceed the remaining data when it comes in.
+			 */
+
+			if (remain < plen) {
+				dlen = plen - remain;
+				b = buf;
+
+				b[0] = 0x90 + n1;
+				put_unaligned_be16(dlen, b + 1);
+
+				remain = 3;
+				goto done;
+			}
+			break;
+
+		/*
+		 *  Handle Window Sequence packets.
+		 */
+
+		case 10:
+			plen = 3;
+			if (remain < plen)
+				goto done;
+
+			nd->nd_tx_work = 1;
+
+			{
+				ushort tpos   = get_unaligned_be16(b + 1);
+
+				ushort ack    = (tpos          - ch->ch_s_tpos) & 0xffff;
+				ushort unack  = (ch->ch_s_tin  - ch->ch_s_tpos) & 0xffff;
+				ushort notify = (ch->ch_s_treq - ch->ch_s_tpos) & 0xffff;
+
+				if (ch->ch_state < CS_READY || ack > unack) {
+					error = "Improper Window Sequence";
+					goto prot_error;
+				}
+
+				ch->ch_s_tpos = tpos;
+
+				if (notify <= ack)
+					ch->ch_s_treq = tpos;
+			}
+			break;
+
+		/*
+		 *  Handle Command response packets.
+		 */
+
+		case 11:
+
+			/*
+			 * RealPort engine fix - 03/11/2004
+			 *
+			 * This check did not used to be here.
+			 *
+			 * We were using b[1] without verifying that the data
+			 * is actually there and valid. On a split packet, it
+			 * might not be yet.
+			 *
+			 * NOTE:  I have never actually seen the failure happen
+			 *        under Linux,  but since I have seen it occur
+			 *        under both Solaris and HP-UX,  the assumption
+			 *        is that it *could* happen here as well...
+			 */
+			if (remain < 2)
+				goto done;
+
+
+			switch (b[1]) {
+
+			/*
+			 *  Handle Open Response.
+			 */
+
+			case 11:
+				plen = 6;
+				if (remain < plen)
+					goto done;
+
+				nd->nd_tx_work = 1;
+
+				{
+					int req = b[2];
+					int resp = b[3];
+					port = get_unaligned_be16(b + 4);
+
+					if (port >= nd->nd_chan_count) {
+						error = "Open channel number out of range";
+						goto prot_error;
+					}
+
+					ch = nd->nd_chan + port;
+
+					/*
+					 *  How we handle an open response depends primarily
+					 *  on our current channel state.
+					 */
+
+					switch (ch->ch_state) {
+					case CS_IDLE:
+
+						/*
+						 *  Handle a delayed open.
+						 */
+
+						if (ch->ch_otype_waiting != 0 &&
+						    req == ch->ch_otype_waiting &&
+						    resp == 0) {
+							ch->ch_otype = req;
+							ch->ch_otype_waiting = 0;
+							ch->ch_state = CS_SEND_QUERY;
+							break;
+						}
+						goto open_error;
+
+					case CS_WAIT_OPEN:
+
+						/*
+						 *  Handle the open response.
+						 */
+
+						if (req == ch->ch_otype) {
+							switch (resp) {
+
+							/*
+							 *  On successful response, open the
+							 *  port and proceed normally.
+							 */
+
+							case 0:
+								ch->ch_state = CS_SEND_QUERY;
+								break;
+
+							/*
+							 *  On a busy response to a persistent open,
+							 *  remember that the open is pending.
+							 */
+
+							case 1:
+							case 2:
+								if (req != OTYPE_IMMEDIATE) {
+									ch->ch_otype_waiting = req;
+									ch->ch_state = CS_IDLE;
+									break;
+								}
+
+							/*
+							 *  Otherwise the server open failed.  If
+							 *  the Unix port is open, hang it up.
+							 */
+
+							default:
+								if (ch->ch_open_count != 0) {
+									ch->ch_flag |= CH_HANGUP;
+									dgrp_carrier(ch);
+									ch->ch_state = CS_IDLE;
+									break;
+								}
+
+								ch->ch_open_error = resp;
+								ch->ch_state = CS_IDLE;
+
+								wake_up_interruptible(&ch->ch_flag_wait);
+							}
+							break;
+						}
+
+						/*
+						 *  Handle delayed response arrival preceeding
+						 *  the open response we are waiting for.
+						 */
+
+						if (ch->ch_otype_waiting != 0 &&
+						    req == ch->ch_otype_waiting &&
+						    resp == 0) {
+							ch->ch_otype = ch->ch_otype_waiting;
+							ch->ch_otype_waiting = 0;
+							ch->ch_state = CS_WAIT_FAIL;
+							break;
+						}
+						goto open_error;
+
+
+					case CS_WAIT_FAIL:
+
+						/*
+						 *  Handle response to immediate open arriving
+						 *  after a delayed open success.
+						 */
+
+						if (req == OTYPE_IMMEDIATE) {
+							ch->ch_state = CS_SEND_QUERY;
+							break;
+						}
+						goto open_error;
+
+
+					case CS_WAIT_CANCEL:
+						/*
+						 *  Handle delayed open response arriving before
+						 *  the cancel response.
+						 */
+
+						if (req == ch->ch_otype_waiting &&
+						    resp == 0) {
+							ch->ch_otype_waiting = 0;
+							break;
+						}
+
+						/*
+						 *  Handle cancel response.
+						 */
+
+						if (req == 4 && resp == 0) {
+							ch->ch_otype_waiting = 0;
+							ch->ch_state = CS_IDLE;
+							break;
+						}
+						goto open_error;
+
+
+					case CS_WAIT_CLOSE:
+						/*
+						 *  Handle a successful response to a port
+						 *  close.
+						 */
+
+						if (req >= 3) {
+							ch->ch_state = CS_IDLE;
+							break;
+						}
+						goto open_error;
+
+open_error:
+					default:
+						{
+							error = "Improper Open Response";
+							goto prot_error;
+						}
+					}
+				}
+				break;
+
+			/*
+			 *  Handle Synchronize Response.
+			 */
+
+			case 13:
+				plen = 3;
+				if (remain < plen)
+					goto done;
+				{
+					int seq = b[2];
+					int s;
+
+					/*
+					 * If channel was waiting for this sync response,
+					 * unset the flag, and wake up anyone waiting
+					 * on the event.
+					 */
+					if (ch->ch_flag & CH_WAITING_SYNC) {
+						ch->ch_flag &= ~(CH_WAITING_SYNC);
+						wake_up_interruptible(&ch->ch_flag_wait);
+					}
+
+					if (((seq - nd->nd_seq_out) & SEQ_MASK) >=
+					    ((nd->nd_seq_in - nd->nd_seq_out) & SEQ_MASK)) {
+						break;
+					}
+
+					for (s = nd->nd_seq_out;; s = (s + 1) & SEQ_MASK) {
+						if (nd->nd_seq_wait[s] != 0) {
+							nd->nd_seq_wait[s] = 0;
+
+							wake_up_interruptible(&nd->nd_seq_wque[s]);
+						}
+
+						nd->nd_unack -= nd->nd_seq_size[s];
+
+						if (s == seq)
+							break;
+					}
+
+					nd->nd_seq_out = (seq + 1) & SEQ_MASK;
+				}
+				break;
+
+			/*
+			 *  Handle Sequence Response.
+			 */
+
+			case 15:
+				plen = 6;
+				if (remain < plen)
+					goto done;
+
+				{
+				/* Record that we have received the Sequence
+				 * Response, but we aren't interested in the
+				 * sequence numbers.  We were using RIN like it
+				 * was ROUT and that was causing problems,
+				 * fixed 7-13-2001 David Fries. See comment in
+				 * drp.h for ch_s_rin variable.
+					int rin = get_unaligned_be16(b + 2);
+					int tpos = get_unaligned_be16(b + 4);
+				*/
+
+					ch->ch_send   &= ~RR_SEQUENCE;
+					ch->ch_expect &= ~RR_SEQUENCE;
+				}
+				goto check_query;
+
+			/*
+			 *  Handle Status Response.
+			 */
+
+			case 17:
+				plen = 5;
+				if (remain < plen)
+					goto done;
+
+				{
+					ch->ch_s_elast = get_unaligned_be16(b + 2);
+					ch->ch_s_mlast = b[4];
+
+					ch->ch_expect &= ~RR_STATUS;
+					ch->ch_send   &= ~RR_STATUS;
+
+					/*
+					 *  CH_PHYS_CD is cleared because something _could_ be
+					 *  waiting for the initial sense of carrier... and if
+					 *  carrier is high immediately, we want to be sure to
+					 *  wake them as soon as possible.
+					 */
+					ch->ch_flag &= ~CH_PHYS_CD;
+
+					dgrp_carrier(ch);
+				}
+				goto check_query;
+
+			/*
+			 *  Handle Line Error Response.
+			 */
+
+			case 19:
+				plen = 14;
+				if (remain < plen)
+					goto done;
+
+				break;
+
+			/*
+			 *  Handle Buffer Response.
+			 */
+
+			case 21:
+				plen = 6;
+				if (remain < plen)
+					goto done;
+
+				{
+					ch->ch_s_rsize = get_unaligned_be16(b + 2);
+					ch->ch_s_tsize = get_unaligned_be16(b + 4);
+
+					ch->ch_send   &= ~RR_BUFFER;
+					ch->ch_expect &= ~RR_BUFFER;
+				}
+				goto check_query;
+
+			/*
+			 *  Handle Port Capability Response.
+			 */
+
+			case 23:
+				plen = 32;
+				if (remain < plen)
+					goto done;
+
+				{
+					ch->ch_send   &= ~RR_CAPABILITY;
+					ch->ch_expect &= ~RR_CAPABILITY;
+				}
+
+			/*
+			 *  When all queries are complete, set those parameters
+			 *  derived from the query results, then transition
+			 *  to the READY state.
+			 */
+
+check_query:
+				if (ch->ch_state == CS_WAIT_QUERY &&
+				    (ch->ch_expect & (RR_SEQUENCE |
+							RR_STATUS |
+							RR_BUFFER |
+							RR_CAPABILITY)) == 0) {
+					ch->ch_tmax  = ch->ch_s_tsize / 4;
+
+					if (ch->ch_edelay == DGRP_TTIME)
+						ch->ch_ttime = DGRP_TTIME;
+					else
+						ch->ch_ttime = ch->ch_edelay;
+
+					ch->ch_rmax = ch->ch_s_rsize / 4;
+
+					if (ch->ch_edelay == DGRP_RTIME)
+						ch->ch_rtime = DGRP_RTIME;
+					else
+						ch->ch_rtime = ch->ch_edelay;
+
+					ch->ch_rlow  = 2 * ch->ch_s_rsize / 8;
+					ch->ch_rhigh = 6 * ch->ch_s_rsize / 8;
+
+					ch->ch_state = CS_READY;
+
+					nd->nd_tx_work = 1;
+					wake_up_interruptible(&ch->ch_flag_wait);
+
+				}
+				break;
+
+			default:
+				goto decode_error;
+			}
+			break;
+
+		/*
+		 *  Handle Events.
+		 */
+
+		case 12:
+			plen = 4;
+			if (remain < plen)
+				goto done;
+
+			mlast = ch->ch_s_mlast;
+			elast = ch->ch_s_elast;
+
+			mstat = ch->ch_s_mlast = b[1];
+			estat = ch->ch_s_elast = get_unaligned_be16(b + 2);
+
+			/*
+			 *  Handle modem changes.
+			 */
+
+			if (((mstat ^ mlast) & DM_CD) != 0)
+				dgrp_carrier(ch);
+
+
+			/*
+			 *  Handle received break.
+			 */
+
+			if ((estat & ~elast & EV_RXB) != 0 &&
+			    (ch->ch_tun.un_open_count != 0) &&
+			    I_BRKINT(ch->ch_tun.un_tty) &&
+			    !(I_IGNBRK(ch->ch_tun.un_tty))) {
+
+				tty_buffer_request_room(ch->ch_tun.un_tty, 1);
+				tty_insert_flip_char(ch->ch_tun.un_tty, 0, TTY_BREAK);
+				tty_flip_buffer_push(ch->ch_tun.un_tty);
+
+			}
+
+			/*
+			 *  On transmit break complete, if more break traffic
+			 *  is waiting then send it.  Otherwise wake any threads
+			 *  waiting for transmitter empty.
+			 */
+
+			if ((~estat & elast & EV_TXB) != 0 &&
+			    (ch->ch_expect & RR_TX_BREAK) != 0) {
+
+				nd->nd_tx_work = 1;
+
+				ch->ch_expect &= ~RR_TX_BREAK;
+
+				if (ch->ch_break_time != 0) {
+					ch->ch_send |= RR_TX_BREAK;
+				} else {
+					ch->ch_send &= ~RR_TX_BREAK;
+					ch->ch_flag &= ~CH_TX_BREAK;
+					wake_up_interruptible(&ch->ch_flag_wait);
+				}
+			}
+			break;
+
+		case 13:
+		case 14:
+			error = "Unrecognized command";
+			goto prot_error;
+
+		/*
+		 *  Decode Special Codes.
+		 */
+
+		case 15:
+			switch (n1) {
+			/*
+			 *  One byte module select.
+			 */
+
+			case 0:
+			case 1:
+			case 2:
+			case 3:
+			case 4:
+			case 5:
+			case 6:
+			case 7:
+				plen = 1;
+				nd->nd_rx_module = n1;
+				break;
+
+			/*
+			 *  Two byte module select.
+			 */
+
+			case 8:
+				plen = 2;
+				if (remain < plen)
+					goto done;
+
+				nd->nd_rx_module = b[1];
+				break;
+
+			/*
+			 *  ID Request packet.
+			 */
+
+			case 11:
+				if (remain < 4)
+					goto done;
+
+				plen = get_unaligned_be16(b + 2);
+
+				if (plen < 12 || plen > 1000) {
+					error = "Response Packet length error";
+					goto prot_error;
+				}
+
+				nd->nd_tx_work = 1;
+
+				switch (b[1]) {
+				/*
+				 *  Echo packet.
+				 */
+
+				case 0:
+					nd->nd_send |= NR_ECHO;
+					break;
+
+				/*
+				 *  ID Response packet.
+				 */
+
+				case 1:
+					nd->nd_send |= NR_IDENT;
+					break;
+
+				/*
+				 *  ID Response packet.
+				 */
+
+				case 32:
+					nd->nd_send |= NR_PASSWORD;
+					break;
+
+				}
+				break;
+
+			/*
+			 *  Various node-level response packets.
+			 */
+
+			case 12:
+				if (remain < 4)
+					goto done;
+
+				plen = get_unaligned_be16(b + 2);
+
+				if (plen < 4 || plen > 1000) {
+					error = "Response Packet length error";
+					goto prot_error;
+				}
+
+				nd->nd_tx_work = 1;
+
+				switch (b[1]) {
+				/*
+				 *  Echo packet.
+				 */
+
+				case 0:
+					nd->nd_expect &= ~NR_ECHO;
+					break;
+
+				/*
+				 *  Product Response Packet.
+				 */
+
+				case 1:
+					{
+						int desclen;
+
+						nd->nd_hw_ver = (b[8] << 8) | b[9];
+						nd->nd_sw_ver = (b[10] << 8) | b[11];
+						nd->nd_hw_id = b[6];
+						desclen = ((plen - 12) > MAX_DESC_LEN) ? MAX_DESC_LEN :
+							plen - 12;
+						strncpy(nd->nd_ps_desc, b + 12, desclen);
+						nd->nd_ps_desc[desclen] = 0;
+					}
+
+					nd->nd_expect &= ~NR_IDENT;
+					break;
+
+				/*
+				 *  Capability Response Packet.
+				 */
+
+				case 2:
+					{
+						int nn = get_unaligned_be16(b + 4);
+
+						if (nn > CHAN_MAX)
+							nn = CHAN_MAX;
+
+						dgrp_chan_count(nd, nn);
+					}
+
+					nd->nd_expect &= ~NR_CAPABILITY;
+					break;
+
+				/*
+				 *  VPD Response Packet.
+				 */
+
+				case 15:
+					/*
+					 * NOTE: case 15 is here ONLY because the EtherLite
+					 * is broken, and sends a response to 24 back as 15.
+					 * To resolve this, the EtherLite firmware is now
+					 * fixed to send back 24 correctly, but, for backwards
+					 * compatibility, we now have reserved 15 for the
+					 * bad EtherLite response to 24 as well.
+					 */
+
+					/* Fallthru! */
+
+				case 24:
+
+					/*
+					 * If the product doesn't support VPD,
+					 * it will send back a null IDRESP,
+					 * which is a length of 4 bytes.
+					 */
+					if (plen > 4) {
+						memcpy(nd->nd_vpd, b + 4, min(plen - 4, (long) VPDSIZE));
+						nd->nd_vpd_len = min(plen - 4, (long) VPDSIZE);
+					}
+
+					nd->nd_expect &= ~NR_VPD;
+					break;
+
+				default:
+					goto decode_error;
+				}
+
+				if (nd->nd_expect == 0 &&
+				    nd->nd_state == NS_WAIT_QUERY) {
+					nd->nd_state = NS_READY;
+				}
+				break;
+
+			/*
+			 *  Debug packet.
+			 */
+
+			case 14:
+				if (remain < 4)
+					goto done;
+
+				plen = get_unaligned_be16(b + 2) + 4;
+
+				if (plen > 1000) {
+					error = "Debug Packet too large";
+					goto prot_error;
+				}
+
+				if (remain < plen)
+					goto done;
+				break;
+
+			/*
+			 *  Handle reset packet.
+			 */
+
+			case 15:
+				if (remain < 2)
+					goto done;
+
+				plen = 2 + b[1];
+
+				if (remain < plen)
+					goto done;
+
+				nd->nd_tx_work = 1;
+
+				n = b[plen];
+				b[plen] = 0;
+
+				b[plen] = n;
+
+				error = "Client Reset Acknowledge";
+				goto prot_error;
+
+			default:
+				goto decode_error;
+			}
+			break;
+
+		default:
+			goto decode_error;
+		}
+
+		b += plen;
+		remain -= plen;
+	}
+
+	/*
+	 *  When the buffer is exhausted, copy any data left at the
+	 *  top of the buffer back down to the bottom for the next
+	 *  read request.
+	 */
+
+done:
+	if (remain > 0 && b != buf)
+		memcpy(buf, b, remain);
+
+	nd->nd_remain = remain;
+	return;
+
+/*
+ *  Handle a decode error.
+ */
+
+decode_error:
+	error = "Protocol decode error";
+
+/*
+ *  Handle a general protocol error.
+ */
+
+prot_error:
+	nd->nd_remain = 0;
+	nd->nd_state = NS_SEND_ERROR;
+	nd->nd_error = error;
+}
+
+/*
+ * dgrp_net_write() -- write data to the network device.
+ *
+ * A zero byte write indicates that the connection to the RealPort
+ * device has been broken.
+ *
+ * A non-zero write indicates data from the RealPort device.
+ */
+static ssize_t dgrp_net_write(struct file *file, const char __user *buf,
+			      size_t count, loff_t *ppos)
+{
+	struct nd_struct *nd;
+	ssize_t rtn = 0;
+	long n;
+	long total = 0;
+
+	/*
+	 *  Get the node pointer, and quit if it doesn't exist.
+	 */
+	nd = (struct nd_struct *)(file->private_data);
+	if (!nd)
+		return -ENXIO;
+
+	/*
+	 *  Grab the NET lock.
+	 */
+	down(&nd->nd_net_semaphore);
+
+	nd->nd_write_count++;
+
+	/*
+	 *  Handle disconnect.
+	 */
+
+	if (count == 0) {
+		dgrp_net_idle(nd);
+		/*
+		 *  Set the active port count to zero.
+		 */
+		dgrp_chan_count(nd, 0);
+		goto unlock;
+	}
+
+	/*
+	 *  Loop to process entire receive packet.
+	 */
+
+	while (count > 0) {
+		n = UIO_MAX - nd->nd_remain;
+
+		if (n > count)
+			n = count;
+
+		nd->nd_rx_byte += n + nd->nd_link.lk_header_size;
+
+		rtn = copy_from_user(nd->nd_iobuf + nd->nd_remain,
+				     (void __user *) buf + total, n);
+		if (rtn) {
+			rtn = -EFAULT;
+			goto unlock;
+		}
+
+		*ppos += n;
+
+		total += n;
+
+		count -= n;
+
+		if (nd->nd_mon_buf)
+			dgrp_monitor_data(nd, RPDUMP_SERVER,
+					  nd->nd_iobuf + nd->nd_remain, n);
+
+		nd->nd_remain += n;
+
+		dgrp_receive(nd);
+	}
+
+	rtn = total;
+
+unlock:
+	/*
+	 *  Release the NET lock.
+	 */
+	up(&nd->nd_net_semaphore);
+
+	return rtn;
+}
+
+
+/*
+ * dgrp_net_select()
+ *  Determine whether a device is ready to be read or written to, and
+ *  sleep if not.
+ */
+static unsigned int dgrp_net_select(struct file *file,
+				    struct poll_table_struct *table)
+{
+	unsigned int retval = 0;
+	struct nd_struct *nd = file->private_data;
+
+	poll_wait(file, &nd->nd_tx_waitq, table);
+
+	if (nd->nd_tx_ready)
+		retval |= POLLIN | POLLRDNORM; /* Conditionally readable */
+
+	retval |= POLLOUT | POLLWRNORM;        /* Always writeable */
+
+	return retval;
+}
+
+/*
+ * dgrp_net_ioctl
+ *
+ * Implement those functions which allow the network daemon to control
+ * the network parameters in the driver.  The ioctls include ones to
+ * get and set the link speed parameters for the PortServer.
+ */
+static long dgrp_net_ioctl(struct file *file, unsigned int cmd,
+			   unsigned long arg)
+{
+	struct nd_struct  *nd;
+	int    rtn = 0;
+	long   size = _IOC_SIZE(cmd);
+	struct link_struct link;
+
+	nd = file->private_data;
+
+	if (_IOC_DIR(cmd) & _IOC_READ)
+		rtn = access_ok(VERIFY_WRITE, (void __user *) arg, size);
+	else if (_IOC_DIR(cmd) & _IOC_WRITE)
+		rtn = access_ok(VERIFY_READ,  (void __user *) arg, size);
+
+	if (!rtn)
+		return rtn;
+
+	switch (cmd) {
+	case DIGI_SETLINK:
+		if (size != sizeof(struct link_struct))
+			return -EINVAL;
+
+		if (copy_from_user((void *)(&link), (void __user *) arg, size))
+			return -EFAULT;
+
+		if (link.lk_fast_rate < 9600)
+			link.lk_fast_rate = 9600;
+
+		if (link.lk_slow_rate < 2400)
+			link.lk_slow_rate = 2400;
+
+		if (link.lk_fast_rate > 10000000)
+			link.lk_fast_rate = 10000000;
+
+		if (link.lk_slow_rate > link.lk_fast_rate)
+			link.lk_slow_rate = link.lk_fast_rate;
+
+		if (link.lk_fast_delay > 2000)
+			link.lk_fast_delay = 2000;
+
+		if (link.lk_slow_delay > 10000)
+			link.lk_slow_delay = 10000;
+
+		if (link.lk_fast_delay < 60)
+			link.lk_fast_delay = 60;
+
+		if (link.lk_slow_delay < link.lk_fast_delay)
+			link.lk_slow_delay = link.lk_fast_delay;
+
+		if (link.lk_header_size < 2)
+			link.lk_header_size = 2;
+
+		if (link.lk_header_size > 128)
+			link.lk_header_size = 128;
+
+		link.lk_fast_rate /= 8 * 1000 / dgrp_poll_tick;
+		link.lk_slow_rate /= 8 * 1000 / dgrp_poll_tick;
+
+		link.lk_fast_delay /= dgrp_poll_tick;
+		link.lk_slow_delay /= dgrp_poll_tick;
+
+		nd->nd_link = link;
+
+		break;
+
+	case DIGI_GETLINK:
+		if (size != sizeof(struct link_struct))
+			return -EINVAL;
+
+		if (copy_to_user((void __user *)arg, (void *)(&nd->nd_link),
+				 size))
+			return -EFAULT;
+
+		break;
+
+	default:
+		return -EINVAL;
+
+	}
+
+	return 0;
+}
+
+/**
+ * dgrp_poll_handler() -- handler for poll timer
+ *
+ * As each timer expires, it determines (a) whether the "transmit"
+ * waiter needs to be woken up, and (b) whether the poller needs to
+ * be rescheduled.
+ */
+void dgrp_poll_handler(unsigned long arg)
+{
+	struct dgrp_poll_data *poll_data;
+	struct nd_struct *nd;
+	struct link_struct *lk;
+	ulong time;
+	ulong poll_time;
+	ulong freq;
+	ulong lock_flags;
+
+	poll_data = (struct dgrp_poll_data *) arg;
+	freq = 1000 / poll_data->poll_tick;
+	poll_data->poll_round += 17;
+
+	if (poll_data->poll_round >= freq)
+		poll_data->poll_round -= freq;
+
+	/*
+	 * Loop to process all open nodes.
+	 *
+	 * For each node, determine the rate at which it should
+	 * be transmitting data.  Then if the node should wake up
+	 * and transmit data now, enable the net receive select
+	 * to get the transmit going.
+	 */
+
+	list_for_each_entry(nd, &nd_struct_list, list) {
+
+		lk = &nd->nd_link;
+
+		/*
+		 * Decrement statistics.  These are only for use with
+		 * KME, so don't worry that the operations are done
+		 * unlocked, and so the results are occassionally wrong.
+		 */
+
+		nd->nd_read_count -= (nd->nd_read_count +
+				      poll_data->poll_round) / freq;
+		nd->nd_write_count -= (nd->nd_write_count +
+				       poll_data->poll_round) / freq;
+		nd->nd_send_count -= (nd->nd_send_count +
+				      poll_data->poll_round) / freq;
+		nd->nd_tx_byte -= (nd->nd_tx_byte +
+				   poll_data->poll_round) / freq;
+		nd->nd_rx_byte -= (nd->nd_rx_byte +
+				   poll_data->poll_round) / freq;
+
+		/*
+		 * Wake the daemon to transmit data only when there is
+		 * enough byte credit to send data.
+		 *
+		 * The results are approximate because the operations
+		 * are performed unlocked, and we are inspecting
+		 * data asynchronously updated elsewhere.  The whole
+		 * thing is just approximation anyway, so that should
+		 * be okay.
+		 */
+
+		if (lk->lk_slow_rate >= UIO_MAX) {
+
+			nd->nd_delay = 0;
+			nd->nd_rate = UIO_MAX;
+
+			nd->nd_tx_deposit = nd->nd_tx_charge + 3 * UIO_MAX;
+			nd->nd_tx_credit  = 3 * UIO_MAX;
+
+		} else {
+
+			long rate;
+			long delay;
+			long deposit;
+			long charge;
+			long size;
+			long excess;
+
+			long seq_in = nd->nd_seq_in;
+			long seq_out = nd->nd_seq_out;
+
+			/*
+			 * If there are no outstanding packets, run at the
+			 * fastest rate.
+			 */
+
+			if (seq_in == seq_out) {
+				delay = 0;
+				rate = lk->lk_fast_rate;
+			}
+
+			/*
+			 * Otherwise compute the transmit rate based on the
+			 * delay since the oldest packet.
+			 */
+
+			else {
+				/*
+				 * The actual delay is computed as the
+				 * time since the oldest unacknowledged
+				 * packet was sent, minus the time it
+				 * took to send that packet to the server.
+				 */
+
+				delay = ((jiffies - nd->nd_seq_time[seq_out])
+					- (nd->nd_seq_size[seq_out] /
+					lk->lk_fast_rate));
+
+				/*
+				 * If the delay is less than the "fast"
+				 * delay, transmit full speed.  If greater
+				 * than the "slow" delay, transmit at the
+				 * "slow" speed.   In between, interpolate
+				 * between the fast and slow speeds.
+				 */
+
+				rate =
+				  (delay <= lk->lk_fast_delay ?
+				    lk->lk_fast_rate :
+				    delay >= lk->lk_slow_delay ?
+				      lk->lk_slow_rate :
+				      (lk->lk_slow_rate +
+				       (lk->lk_slow_delay - delay) *
+				       (lk->lk_fast_rate - lk->lk_slow_rate) /
+				       (lk->lk_slow_delay - lk->lk_fast_delay)
+				      )
+				  );
+			}
+
+			nd->nd_delay = delay;
+			nd->nd_rate = rate;
+
+			/*
+			 * Increase the transmit credit by depositing the
+			 * current transmit rate.
+			 */
+
+			deposit = nd->nd_tx_deposit;
+			charge  = nd->nd_tx_charge;
+
+			deposit += rate;
+
+			/*
+			 * If the available transmit credit becomes too large,
+			 * reduce the deposit to correct the value.
+			 *
+			 * Too large is the max of:
+			 *		6 times the header size
+			 *		3 times the current transmit rate.
+			 */
+
+			size = 2 * nd->nd_link.lk_header_size;
+
+			if (size < rate)
+				size = rate;
+
+			size *= 3;
+
+			excess = deposit - charge - size;
+
+			if (excess > 0)
+				deposit -= excess;
+
+			nd->nd_tx_deposit = deposit;
+			nd->nd_tx_credit  = deposit - charge;
+
+			/*
+			 * Wake the transmit task only if the transmit credit
+			 * is at least 3 times the transmit header size.
+			 */
+
+			size = 3 * lk->lk_header_size;
+
+			if (nd->nd_tx_credit < size)
+				continue;
+		}
+
+
+		/*
+		 * Enable the READ select to wake the daemon if there
+		 * is useful work for the drp_read routine to perform.
+		 */
+
+		if (waitqueue_active(&nd->nd_tx_waitq) &&
+		    (nd->nd_tx_work != 0 ||
+		    (ulong)(jiffies - nd->nd_tx_time) >= IDLE_MAX)) {
+			nd->nd_tx_ready = 1;
+
+			wake_up_interruptible(&nd->nd_tx_waitq);
+
+			/* not needed */
+			/* nd->nd_flag &= ~ND_SELECT; */
+		}
+	}
+
+
+	/*
+	 * Schedule ourself back at the nominal wakeup interval.
+	 */
+	spin_lock_irqsave(&poll_data->poll_lock, lock_flags);
+
+	poll_data->node_active_count--;
+	if (poll_data->node_active_count > 0) {
+		poll_data->node_active_count++;
+		poll_time = poll_data->timer.expires +
+			poll_data->poll_tick * HZ / 1000;
+
+		time = poll_time - jiffies;
+
+		if (time >= 2 * poll_data->poll_tick)
+			poll_time = jiffies + dgrp_poll_tick * HZ / 1000;
+
+		poll_data->timer.expires = poll_time;
+		add_timer(&poll_data->timer);
+	}
+
+	spin_unlock_irqrestore(&poll_data->poll_lock, lock_flags);
+}
diff --git a/drivers/staging/dgrp/dgrp_ports_ops.c b/drivers/staging/dgrp/dgrp_ports_ops.c
new file mode 100644
index 000000000000..cd1fc2088624
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_ports_ops.c
@@ -0,0 +1,170 @@
+/*
+ *
+ * Copyright 1999-2000 Digi International (www.digi.com)
+ *     James Puzzo <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_ports_ops.c
+ *
+ *  Description:
+ *
+ *     Handle the file operations required for the /proc/dgrp/ports/...
+ *     devices.  Basically gathers tty status for the node and returns it.
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/tty.h>
+#include <linux/sched.h>
+#include <linux/seq_file.h>
+
+#include "dgrp_common.h"
+
+/* File operation declarations */
+static int dgrp_ports_open(struct inode *, struct file *);
+
+static const struct file_operations ports_ops = {
+	.owner   = THIS_MODULE,
+	.open    = dgrp_ports_open,
+	.read    = seq_read,
+	.llseek	 = seq_lseek,
+	.release = seq_release
+};
+
+static struct inode_operations ports_inode_ops = {
+	.permission = dgrp_inode_permission
+};
+
+
+void dgrp_register_ports_hook(struct proc_dir_entry *de)
+{
+	struct nd_struct *node = de->data;
+
+	de->proc_iops = &ports_inode_ops;
+	de->proc_fops = &ports_ops;
+	node->nd_ports_de = de;
+}
+
+static void *dgrp_ports_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	if (*pos == 0)
+		seq_puts(seq, "#num tty_open pr_open tot_wait MSTAT  IFLAG  OFLAG  CFLAG  BPS    DIGIFLAGS\n");
+
+	return pos;
+}
+
+static void *dgrp_ports_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct nd_struct *nd = seq->private;
+
+	if (*pos >= nd->nd_chan_count)
+		return NULL;
+
+	*pos += 1;
+
+	return pos;
+}
+
+static void dgrp_ports_seq_stop(struct seq_file *seq, void *v)
+{
+}
+
+static int dgrp_ports_seq_show(struct seq_file *seq, void *v)
+{
+	loff_t *pos = v;
+	struct nd_struct *nd;
+	struct ch_struct *ch;
+	struct un_struct *tun, *pun;
+	unsigned int totcnt;
+
+	nd = seq->private;
+	if (!nd)
+		return 0;
+
+	if (*pos >= nd->nd_chan_count)
+		return 0;
+
+	ch = &nd->nd_chan[*pos];
+	tun = &ch->ch_tun;
+	pun = &ch->ch_pun;
+
+	/*
+	 * If port is not open and no one is waiting to
+	 * open it, the modem signal values can't be
+	 * trusted, and will be zeroed.
+	 */
+	totcnt = tun->un_open_count +
+		pun->un_open_count +
+		ch->ch_wait_count[0] +
+		ch->ch_wait_count[1] +
+		ch->ch_wait_count[2];
+
+	seq_printf(seq, "%02d      %02d      %02d      %02d     0x%04X 0x%04X 0x%04X 0x%04X %-6d 0x%04X\n",
+		   (int) *pos,
+		   tun->un_open_count,
+		   pun->un_open_count,
+		   ch->ch_wait_count[0] +
+		   ch->ch_wait_count[1] +
+		   ch->ch_wait_count[2],
+		   (totcnt ? ch->ch_s_mlast : 0),
+		   ch->ch_s_iflag,
+		   ch->ch_s_oflag,
+		   ch->ch_s_cflag,
+		   (ch->ch_s_brate ? (1843200 / ch->ch_s_brate) : 0),
+		   ch->ch_digi.digi_flags);
+
+	return 0;
+}
+
+static const struct seq_operations ports_seq_ops = {
+	.start = dgrp_ports_seq_start,
+	.next  = dgrp_ports_seq_next,
+	.stop  = dgrp_ports_seq_stop,
+	.show  = dgrp_ports_seq_show,
+};
+
+/**
+ * dgrp_ports_open -- open the /proc/dgrp/ports/... device
+ * @inode: struct inode *
+ * @file: struct file *
+ *
+ * Open function to open the /proc/dgrp/ports device for a PortServer.
+ * This is the open function for struct file_operations
+ */
+static int dgrp_ports_open(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq;
+	int rtn;
+
+	rtn = seq_open(file, &ports_seq_ops);
+	if (!rtn) {
+		seq = file->private_data;
+		seq->private = PDE(inode)->data;
+	}
+
+	return rtn;
+}
diff --git a/drivers/staging/dgrp/dgrp_specproc.c b/drivers/staging/dgrp/dgrp_specproc.c
new file mode 100644
index 000000000000..259d23aa6c29
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_specproc.c
@@ -0,0 +1,821 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     James Puzzo  <jamesp at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_specproc.c
+ *
+ *  Description:
+ *
+ *     Handle the "config" proc entry for the linux realport device driver
+ *     and provide slots for the "net" and "mon" devices
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/tty.h>
+#include <linux/sched.h>
+#include <linux/cred.h>
+#include <linux/proc_fs.h>
+#include <linux/ctype.h>
+#include <linux/seq_file.h>
+
+#include "dgrp_common.h"
+
+static struct dgrp_proc_entry dgrp_table[];
+static struct proc_dir_entry *dgrp_proc_dir_entry;
+
+static int dgrp_add_id(long id);
+static int dgrp_remove_nd(struct nd_struct *nd);
+static void unregister_dgrp_device(struct proc_dir_entry *de);
+static void register_dgrp_device(struct nd_struct *node,
+				 struct proc_dir_entry *root,
+				 void (*register_hook)(struct proc_dir_entry *de));
+
+/* File operation declarations */
+static int dgrp_gen_proc_open(struct inode *, struct file *);
+static int dgrp_gen_proc_close(struct inode *, struct file *);
+static int parse_write_config(char *);
+
+
+static const struct file_operations dgrp_proc_file_ops = {
+	.owner   = THIS_MODULE,
+	.open    = dgrp_gen_proc_open,
+	.release = dgrp_gen_proc_close,
+};
+
+static struct inode_operations proc_inode_ops = {
+	.permission = dgrp_inode_permission
+};
+
+
+static void register_proc_table(struct dgrp_proc_entry *,
+				struct proc_dir_entry *);
+static void unregister_proc_table(struct dgrp_proc_entry *,
+				  struct proc_dir_entry *);
+
+static struct dgrp_proc_entry dgrp_net_table[];
+static struct dgrp_proc_entry dgrp_mon_table[];
+static struct dgrp_proc_entry dgrp_ports_table[];
+static struct dgrp_proc_entry dgrp_dpa_table[];
+
+static ssize_t config_proc_write(struct file *file, const char __user *buffer,
+				 size_t count, loff_t *pos);
+
+static int nodeinfo_proc_open(struct inode *inode, struct file *file);
+static int info_proc_open(struct inode *inode, struct file *file);
+static int config_proc_open(struct inode *inode, struct file *file);
+
+static struct file_operations config_proc_file_ops = {
+	.owner	 = THIS_MODULE,
+	.open	 = config_proc_open,
+	.read	 = seq_read,
+	.llseek	 = seq_lseek,
+	.release = seq_release,
+	.write   = config_proc_write
+};
+
+static struct file_operations info_proc_file_ops = {
+	.owner	 = THIS_MODULE,
+	.open	 = info_proc_open,
+	.read	 = seq_read,
+	.llseek	 = seq_lseek,
+	.release = seq_release,
+};
+
+static struct file_operations nodeinfo_proc_file_ops = {
+	.owner	 = THIS_MODULE,
+	.open	 = nodeinfo_proc_open,
+	.read	 = seq_read,
+	.llseek	 = seq_lseek,
+	.release = seq_release,
+};
+
+static struct dgrp_proc_entry dgrp_table[] = {
+	{
+		.id = DGRP_CONFIG,
+		.name = "config",
+		.mode = 0644,
+		.proc_file_ops = &config_proc_file_ops,
+	},
+	{
+		.id = DGRP_INFO,
+		.name = "info",
+		.mode = 0644,
+		.proc_file_ops = &info_proc_file_ops,
+	},
+	{
+		.id = DGRP_NODEINFO,
+		.name = "nodeinfo",
+		.mode = 0644,
+		.proc_file_ops = &nodeinfo_proc_file_ops,
+	},
+	{
+		.id = DGRP_NETDIR,
+		.name = "net",
+		.mode = 0500,
+		.child = dgrp_net_table
+	},
+	{
+		.id = DGRP_MONDIR,
+		.name = "mon",
+		.mode = 0500,
+		.child = dgrp_mon_table
+	},
+	{
+		.id = DGRP_PORTSDIR,
+		.name = "ports",
+		.mode = 0500,
+		.child = dgrp_ports_table
+	},
+	{
+		.id = DGRP_DPADIR,
+		.name = "dpa",
+		.mode = 0500,
+		.child = dgrp_dpa_table
+	}
+};
+
+static struct proc_dir_entry *net_entry_pointer;
+static struct proc_dir_entry *mon_entry_pointer;
+static struct proc_dir_entry *dpa_entry_pointer;
+static struct proc_dir_entry *ports_entry_pointer;
+
+static struct dgrp_proc_entry dgrp_net_table[] = {
+	{0}
+};
+
+static struct dgrp_proc_entry dgrp_mon_table[] = {
+	{0}
+};
+
+static struct dgrp_proc_entry dgrp_ports_table[] = {
+	{0}
+};
+
+static struct dgrp_proc_entry dgrp_dpa_table[] = {
+	{0}
+};
+
+void dgrp_unregister_proc(void)
+{
+	unregister_proc_table(dgrp_table, dgrp_proc_dir_entry);
+	net_entry_pointer = NULL;
+	mon_entry_pointer = NULL;
+	dpa_entry_pointer = NULL;
+	ports_entry_pointer = NULL;
+
+	if (dgrp_proc_dir_entry) {
+		remove_proc_entry(dgrp_proc_dir_entry->name,
+				  dgrp_proc_dir_entry->parent);
+		dgrp_proc_dir_entry = NULL;
+	}
+
+}
+
+void dgrp_register_proc(void)
+{
+	/*
+	 *	Register /proc/dgrp
+	 */
+	dgrp_proc_dir_entry = proc_create("dgrp", S_IFDIR, NULL,
+					  &dgrp_proc_file_ops);
+	register_proc_table(dgrp_table, dgrp_proc_dir_entry);
+}
+
+/*
+ * /proc/sys support
+ */
+static int dgrp_proc_match(int len, const char *name, struct proc_dir_entry *de)
+{
+	if (!de || !de->low_ino)
+		return 0;
+	if (de->namelen != len)
+		return 0;
+	return !memcmp(name, de->name, len);
+}
+
+
+/*
+ *  Scan the entries in table and add them all to /proc at the position
+ *  referred to by "root"
+ */
+static void register_proc_table(struct dgrp_proc_entry *table,
+				struct proc_dir_entry *root)
+{
+	struct proc_dir_entry *de;
+	int len;
+	mode_t mode;
+
+	for (; table->id; table++) {
+		/* Can't do anything without a proc name. */
+		if (!table->name)
+			continue;
+
+		/* Maybe we can't do anything with it... */
+		if (!table->proc_file_ops &&
+		    !table->child) {
+			pr_warn("dgrp: Can't register %s\n",
+				table->name);
+			continue;
+		}
+
+		len = strlen(table->name);
+		mode = table->mode;
+
+		de = NULL;
+		if (!table->child)
+			mode |= S_IFREG;
+		else {
+			mode |= S_IFDIR;
+			for (de = root->subdir; de; de = de->next) {
+				if (dgrp_proc_match(len, table->name, de))
+					break;
+			}
+			/* If the subdir exists already, de is non-NULL */
+		}
+
+		if (!de) {
+			de = create_proc_entry(table->name, mode, root);
+			if (!de)
+				continue;
+			de->data = (void *) table;
+			if (!table->child) {
+				de->proc_iops = &proc_inode_ops;
+				if (table->proc_file_ops)
+					de->proc_fops = table->proc_file_ops;
+				else
+					de->proc_fops = &dgrp_proc_file_ops;
+			}
+		}
+		table->de = de;
+		if (de->mode & S_IFDIR)
+			register_proc_table(table->child, de);
+
+		if (table->id == DGRP_NETDIR)
+			net_entry_pointer = de;
+
+		if (table->id == DGRP_MONDIR)
+			mon_entry_pointer = de;
+
+		if (table->id == DGRP_DPADIR)
+			dpa_entry_pointer = de;
+
+		if (table->id == DGRP_PORTSDIR)
+			ports_entry_pointer = de;
+	}
+}
+
+/*
+ * Unregister a /proc sysctl table and any subdirectories.
+ */
+static void unregister_proc_table(struct dgrp_proc_entry *table,
+				  struct proc_dir_entry *root)
+{
+	struct proc_dir_entry *de;
+	struct nd_struct *tmp;
+
+	list_for_each_entry(tmp, &nd_struct_list, list) {
+		if ((table == dgrp_net_table) && (tmp->nd_net_de)) {
+			unregister_dgrp_device(tmp->nd_net_de);
+			dgrp_remove_node_class_sysfs_files(tmp);
+		}
+
+		if ((table == dgrp_mon_table) && (tmp->nd_mon_de))
+			unregister_dgrp_device(tmp->nd_mon_de);
+
+		if ((table == dgrp_dpa_table) && (tmp->nd_dpa_de))
+			unregister_dgrp_device(tmp->nd_dpa_de);
+
+		if ((table == dgrp_ports_table) && (tmp->nd_ports_de))
+			unregister_dgrp_device(tmp->nd_ports_de);
+	}
+
+	for (; table->id; table++) {
+		de = table->de;
+
+		if (!de)
+			continue;
+		if (de->mode & S_IFDIR) {
+			if (!table->child) {
+				pr_alert("dgrp: malformed sysctl tree on free\n");
+				continue;
+			}
+			unregister_proc_table(table->child, de);
+
+	/* Don't unregister directories which still have entries */
+			if (de->subdir)
+				continue;
+		}
+
+		/* Don't unregister proc entries that are still being used.. */
+		if ((atomic_read(&de->count)) != 1) {
+			pr_alert("proc entry %s in use, not removing\n",
+				de->name);
+			continue;
+		}
+
+		remove_proc_entry(de->name, de->parent);
+		table->de = NULL;
+	}
+}
+
+static int dgrp_gen_proc_open(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de;
+	struct dgrp_proc_entry *entry;
+	int ret = 0;
+
+	de = (struct proc_dir_entry *) PDE(file->f_dentry->d_inode);
+	if (!de || !de->data) {
+		ret = -ENXIO;
+		goto done;
+	}
+
+	entry = (struct dgrp_proc_entry *) de->data;
+	if (!entry) {
+		ret = -ENXIO;
+		goto done;
+	}
+
+	down(&entry->excl_sem);
+
+	if (entry->excl_cnt)
+		ret = -EBUSY;
+	else
+		entry->excl_cnt++;
+
+	up(&entry->excl_sem);
+
+done:
+	return ret;
+}
+
+static int dgrp_gen_proc_close(struct inode *inode, struct file *file)
+{
+	struct proc_dir_entry *de;
+	struct dgrp_proc_entry *entry;
+
+	de = (struct proc_dir_entry *) PDE(file->f_dentry->d_inode);
+	if (!de || !de->data)
+		goto done;
+
+	entry = (struct dgrp_proc_entry *) de->data;
+	if (!entry)
+		goto done;
+
+	down(&entry->excl_sem);
+
+	if (entry->excl_cnt)
+		entry->excl_cnt = 0;
+
+	up(&entry->excl_sem);
+
+done:
+	return 0;
+}
+
+static void *config_proc_start(struct seq_file *m, loff_t *pos)
+{
+	return seq_list_start_head(&nd_struct_list, *pos);
+}
+
+static void *config_proc_next(struct seq_file *p, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &nd_struct_list, pos);
+}
+
+static void config_proc_stop(struct seq_file *m, void *v)
+{
+}
+
+static int config_proc_show(struct seq_file *m, void *v)
+{
+	struct nd_struct *nd;
+	char tmp_id[4];
+
+	if (v == &nd_struct_list) {
+		seq_puts(m, "#-----------------------------------------------------------------------------\n");
+		seq_puts(m, "#                        Avail\n");
+		seq_puts(m, "# ID  Major  State       Ports\n");
+		return 0;
+	}
+
+	nd = list_entry(v, struct nd_struct, list);
+
+	ID_TO_CHAR(nd->nd_ID, tmp_id);
+
+	seq_printf(m, "  %-2.2s  %-5ld  %-10.10s  %-5d\n",
+		   tmp_id,
+		   nd->nd_major,
+		   ND_STATE_STR(nd->nd_state),
+		   nd->nd_chan_count);
+
+	return 0;
+}
+
+static const struct seq_operations proc_config_ops = {
+	.start = config_proc_start,
+	.next  = config_proc_next,
+	.stop  = config_proc_stop,
+	.show  = config_proc_show
+};
+
+static int config_proc_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &proc_config_ops);
+}
+
+
+/*
+ *  When writing configuration information, each "record" (i.e. each
+ *  write) is treated as an independent request.  See the "parse"
+ *  description for more details.
+ */
+static ssize_t config_proc_write(struct file *file, const char __user *buffer,
+				 size_t count, loff_t *pos)
+{
+	ssize_t retval;
+	char *inbuf, *sp;
+	char *line, *ldelim;
+
+	if (count > 32768)
+		return -EINVAL;
+
+	inbuf = sp = vzalloc(count + 1);
+	if (!inbuf)
+		return -ENOMEM;
+
+	if (copy_from_user(inbuf, buffer, count)) {
+		retval = -EFAULT;
+		goto done;
+	}
+
+	inbuf[count] = 0;
+
+	ldelim = "\n";
+
+	line = strpbrk(sp, ldelim);
+	while (line) {
+		*line = 0;
+		retval = parse_write_config(sp);
+		if (retval)
+			goto done;
+
+		sp = line + 1;
+		line = strpbrk(sp, ldelim);
+	}
+
+	retval = count;
+done:
+	vfree(inbuf);
+	return retval;
+}
+
+/*
+ *  ------------------------------------------------------------------------
+ *
+ *  The following are the functions to parse input
+ *
+ *  ------------------------------------------------------------------------
+ */
+static inline char *skip_past_ws(const char *str)
+{
+	while ((*str) && !isspace(*str))
+		++str;
+
+	return skip_spaces(str);
+}
+
+static int parse_id(char **c, char *cID)
+{
+	int tmp = **c;
+
+	if (isalnum(tmp) || (tmp == '_'))
+		cID[0] = tmp;
+	else
+		return -EINVAL;
+
+	(*c)++; tmp = **c;
+
+	if (isalnum(tmp) || (tmp == '_')) {
+		cID[1] = tmp;
+		(*c)++;
+	} else
+		cID[1] = 0;
+
+	return 0;
+}
+
+static int parse_add_config(char *buf)
+{
+	char *c = buf;
+	int  retval;
+	char cID[2];
+	long ID;
+
+	c = skip_past_ws(c);
+
+	retval = parse_id(&c, cID);
+	if (retval < 0)
+		return retval;
+
+	ID = CHAR_TO_ID(cID);
+
+	c = skip_past_ws(c);
+
+	return dgrp_add_id(ID);
+}
+
+static int parse_del_config(char *buf)
+{
+	char *c = buf;
+	int  retval;
+	struct nd_struct *nd;
+	char cID[2];
+	long ID;
+	long major;
+
+	c = skip_past_ws(c);
+
+	retval = parse_id(&c, cID);
+	if (retval < 0)
+		return retval;
+
+	ID = CHAR_TO_ID(cID);
+
+	c = skip_past_ws(c);
+
+	retval = kstrtol(c, 10, &major);
+	if (retval)
+		return retval;
+
+	nd = nd_struct_get(major);
+	if (!nd)
+		return -EINVAL;
+
+	if ((nd->nd_major != major) || (nd->nd_ID != ID))
+		return -EINVAL;
+
+	return dgrp_remove_nd(nd);
+}
+
+static int parse_chg_config(char *buf)
+{
+	return -EINVAL;
+}
+
+/*
+ *  The passed character buffer represents a single configuration request.
+ *  If the first character is a "+", it is parsed as a request to add a
+ *     PortServer
+ *  If the first character is a "-", it is parsed as a request to delete a
+ *     PortServer
+ *  If the first character is a "*", it is parsed as a request to change a
+ *     PortServer
+ *  Any other character (including whitespace) causes the record to be
+ *     ignored.
+ */
+static int parse_write_config(char *buf)
+{
+	int retval;
+
+	switch (buf[0]) {
+	case '+':
+		retval = parse_add_config(buf);
+		break;
+	case '-':
+		retval = parse_del_config(buf);
+		break;
+	case '*':
+		retval = parse_chg_config(buf);
+		break;
+	default:
+		retval = -EINVAL;
+	}
+
+	return retval;
+}
+
+static int info_proc_show(struct seq_file *m, void *v)
+{
+	seq_printf(m, "version: %s\n", DIGI_VERSION);
+	seq_puts(m, "register_with_sysfs: 1\n");
+	seq_printf(m, "rawreadok: 0x%08x\t(%d)\n",
+		   dgrp_rawreadok, dgrp_rawreadok);
+	seq_printf(m, "pollrate: 0x%08x\t(%d)\n",
+		   dgrp_poll_tick, dgrp_poll_tick);
+
+	return 0;
+}
+
+static int info_proc_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, info_proc_show, NULL);
+}
+
+
+static void *nodeinfo_start(struct seq_file *m, loff_t *pos)
+{
+	return seq_list_start_head(&nd_struct_list, *pos);
+}
+
+static void *nodeinfo_next(struct seq_file *p, void *v, loff_t *pos)
+{
+	return seq_list_next(v, &nd_struct_list, pos);
+}
+
+static void nodeinfo_stop(struct seq_file *m, void *v)
+{
+}
+
+static int nodeinfo_show(struct seq_file *m, void *v)
+{
+	struct nd_struct *nd;
+	char hwver[8];
+	char swver[8];
+	char tmp_id[4];
+
+	if (v == &nd_struct_list) {
+		seq_puts(m, "#-----------------------------------------------------------------------------\n");
+		seq_puts(m, "#                 HW       HW   SW\n");
+		seq_puts(m, "# ID  State       Version  ID   Version  Description\n");
+		return 0;
+	}
+
+	nd = list_entry(v, struct nd_struct, list);
+
+	ID_TO_CHAR(nd->nd_ID, tmp_id);
+
+	if (nd->nd_state == NS_READY) {
+		sprintf(hwver, "%d.%d", (nd->nd_hw_ver >> 8) & 0xff,
+			nd->nd_hw_ver & 0xff);
+		sprintf(swver, "%d.%d", (nd->nd_sw_ver >> 8) & 0xff,
+			nd->nd_sw_ver & 0xff);
+		seq_printf(m, "  %-2.2s  %-10.10s  %-7.7s  %-3d  %-7.7s  %-35.35s\n",
+			   tmp_id,
+			   ND_STATE_STR(nd->nd_state),
+			   hwver,
+			   nd->nd_hw_id,
+			   swver,
+			   nd->nd_ps_desc);
+
+	} else {
+		seq_printf(m, "  %-2.2s  %-10.10s\n",
+			   tmp_id,
+			   ND_STATE_STR(nd->nd_state));
+	}
+
+	return 0;
+}
+
+
+static const struct seq_operations nodeinfo_ops = {
+	.start = nodeinfo_start,
+	.next  = nodeinfo_next,
+	.stop  = nodeinfo_stop,
+	.show  = nodeinfo_show
+};
+
+static int nodeinfo_proc_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &nodeinfo_ops);
+}
+
+/**
+ * dgrp_add_id() -- creates new nd struct and adds it to list
+ * @id: id of device to add
+ */
+static int dgrp_add_id(long id)
+{
+	struct nd_struct *nd;
+	int ret;
+	int i;
+
+	nd = kzalloc(sizeof(struct nd_struct), GFP_KERNEL);
+	if (!nd)
+		return -ENOMEM;
+
+	nd->nd_major = 0;
+	nd->nd_ID = id;
+
+	spin_lock_init(&nd->nd_lock);
+
+	init_waitqueue_head(&nd->nd_tx_waitq);
+	init_waitqueue_head(&nd->nd_mon_wqueue);
+	init_waitqueue_head(&nd->nd_dpa_wqueue);
+	for (i = 0; i < SEQ_MAX; i++)
+		init_waitqueue_head(&nd->nd_seq_wque[i]);
+
+	/* setup the structures to get the major number */
+	ret = dgrp_tty_init(nd);
+	if (ret)
+		goto error_out;
+
+	nd->nd_major = nd->nd_serial_ttdriver->major;
+
+	ret = nd_struct_add(nd);
+	if (ret)
+		goto error_out;
+
+	register_dgrp_device(nd, net_entry_pointer, dgrp_register_net_hook);
+	register_dgrp_device(nd, mon_entry_pointer, dgrp_register_mon_hook);
+	register_dgrp_device(nd, dpa_entry_pointer, dgrp_register_dpa_hook);
+	register_dgrp_device(nd, ports_entry_pointer,
+			      dgrp_register_ports_hook);
+
+	return 0;
+
+error_out:
+	kfree(nd);
+	return ret;
+
+}
+
+static int dgrp_remove_nd(struct nd_struct *nd)
+{
+	int ret;
+
+	/* Check to see if the selected structure is in use */
+	if (nd->nd_tty_ref_cnt)
+		return -EBUSY;
+
+	if (nd->nd_net_de) {
+		unregister_dgrp_device(nd->nd_net_de);
+		dgrp_remove_node_class_sysfs_files(nd);
+	}
+
+	if (nd->nd_mon_de)
+		unregister_dgrp_device(nd->nd_mon_de);
+
+	if (nd->nd_ports_de)
+		unregister_dgrp_device(nd->nd_ports_de);
+
+	if (nd->nd_dpa_de)
+		unregister_dgrp_device(nd->nd_dpa_de);
+
+	dgrp_tty_uninit(nd);
+
+	ret = nd_struct_del(nd);
+	if (ret)
+		return ret;
+
+	kfree(nd);
+	return 0;
+}
+
+static void register_dgrp_device(struct nd_struct *node,
+				 struct proc_dir_entry *root,
+				 void (*register_hook)(struct proc_dir_entry *de))
+{
+	char buf[3];
+	struct proc_dir_entry *de;
+
+	ID_TO_CHAR(node->nd_ID, buf);
+
+	de = create_proc_entry(buf, 0600 | S_IFREG, root);
+	if (!de)
+		return;
+
+	de->data = (void *) node;
+
+	if (register_hook)
+		register_hook(de);
+
+}
+
+static void unregister_dgrp_device(struct proc_dir_entry *de)
+{
+	if (!de)
+		return;
+
+	/* Don't unregister proc entries that are still being used.. */
+	if ((atomic_read(&de->count)) != 1) {
+		pr_alert("%s - proc entry %s in use. Not removing.\n",
+			 __func__, de->name);
+		return;
+	}
+
+	remove_proc_entry(de->name, de->parent);
+	de = NULL;
+}
diff --git a/drivers/staging/dgrp/dgrp_sysfs.c b/drivers/staging/dgrp/dgrp_sysfs.c
new file mode 100644
index 000000000000..e5a3c88d016e
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_sysfs.c
@@ -0,0 +1,555 @@
+/*
+ * Copyright 2004 Digi International (www.digi.com)
+ *      Scott H Kilau <Scott_Kilau at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+#include "dgrp_common.h"
+
+#include <linux/kernel.h>
+#include <linux/version.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+#include <linux/serial_reg.h>
+#include <linux/pci.h>
+#include <linux/kdev_t.h>
+
+
+#define PORTSERVER_DIVIDEND 1843200
+#define SERIAL_TYPE_NORMAL      1
+#define SERIAL_TYPE_CALLOUT     2
+#define SERIAL_TYPE_XPRINT      3
+
+
+static struct class *dgrp_class;
+static struct device *dgrp_class_nodes_dev;
+static struct device *dgrp_class_global_settings_dev;
+
+
+static ssize_t dgrp_class_version_show(struct class *class,
+				       struct class_attribute *attr, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%s\n", DIGI_VERSION);
+}
+static CLASS_ATTR(driver_version, 0400, dgrp_class_version_show, NULL);
+
+
+static ssize_t dgrp_class_register_with_sysfs_show(struct device *c,
+						   struct device_attribute *attr,
+						   char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "1\n");
+}
+static DEVICE_ATTR(register_with_sysfs, 0400,
+		   dgrp_class_register_with_sysfs_show, NULL);
+
+
+static ssize_t dgrp_class_rawreadok_show(struct device *c,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", dgrp_rawreadok);
+}
+static ssize_t dgrp_class_rawreadok_store(struct device *c,
+					  struct device_attribute *attr,
+					  const char *buf, size_t count)
+{
+	sscanf(buf, "0x%x\n", &dgrp_rawreadok);
+	return count;
+}
+static DEVICE_ATTR(rawreadok, 0600, dgrp_class_rawreadok_show,
+		   dgrp_class_rawreadok_store);
+
+
+static ssize_t dgrp_class_pollrate_show(struct device *c,
+					struct device_attribute *attr,
+					char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "%d\n", dgrp_poll_tick);
+}
+
+static ssize_t dgrp_class_pollrate_store(struct device *c,
+					 struct device_attribute *attr,
+					 const char *buf, size_t count)
+{
+	sscanf(buf, "0x%x\n", &dgrp_poll_tick);
+	return count;
+}
+static DEVICE_ATTR(pollrate, 0600, dgrp_class_pollrate_show,
+		   dgrp_class_pollrate_store);
+
+static struct attribute *dgrp_sysfs_global_settings_entries[] = {
+	&dev_attr_pollrate.attr,
+	&dev_attr_rawreadok.attr,
+	&dev_attr_register_with_sysfs.attr,
+	NULL
+};
+
+
+static struct attribute_group dgrp_global_settings_attribute_group = {
+	.name = NULL,
+	.attrs = dgrp_sysfs_global_settings_entries,
+};
+
+
+
+void dgrp_create_class_sysfs_files(void)
+{
+	int ret = 0;
+	int max_majors = 1U << (32 - MINORBITS);
+
+	dgrp_class = class_create(THIS_MODULE, "digi_realport");
+	ret = class_create_file(dgrp_class, &class_attr_driver_version);
+
+	dgrp_class_global_settings_dev = device_create(dgrp_class, NULL,
+		MKDEV(0, max_majors + 1), NULL, "driver_settings");
+
+	ret = sysfs_create_group(&dgrp_class_global_settings_dev->kobj,
+		&dgrp_global_settings_attribute_group);
+	if (ret) {
+		pr_alert("%s: failed to create sysfs global settings device attributes.\n",
+			__func__);
+		sysfs_remove_group(&dgrp_class_global_settings_dev->kobj,
+			&dgrp_global_settings_attribute_group);
+		return;
+	}
+
+	dgrp_class_nodes_dev = device_create(dgrp_class, NULL,
+		MKDEV(0, max_majors + 2), NULL, "nodes");
+
+}
+
+
+void dgrp_remove_class_sysfs_files(void)
+{
+	struct nd_struct *nd;
+	int max_majors = 1U << (32 - MINORBITS);
+
+	list_for_each_entry(nd, &nd_struct_list, list)
+		dgrp_remove_node_class_sysfs_files(nd);
+
+	sysfs_remove_group(&dgrp_class_global_settings_dev->kobj,
+		&dgrp_global_settings_attribute_group);
+
+	class_remove_file(dgrp_class, &class_attr_driver_version);
+
+	device_destroy(dgrp_class, MKDEV(0, max_majors + 1));
+	device_destroy(dgrp_class, MKDEV(0, max_majors + 2));
+	class_destroy(dgrp_class);
+}
+
+static ssize_t dgrp_node_state_show(struct device *c,
+				    struct device_attribute *attr, char *buf)
+{
+	struct nd_struct *nd;
+
+	if (!c)
+		return 0;
+	nd = (struct nd_struct *) dev_get_drvdata(c);
+	if (!nd)
+		return 0;
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", ND_STATE_STR(nd->nd_state));
+}
+
+static DEVICE_ATTR(state, 0600, dgrp_node_state_show, NULL);
+
+static ssize_t dgrp_node_description_show(struct device *c,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct nd_struct *nd;
+
+	if (!c)
+		return 0;
+	nd = (struct nd_struct *) dev_get_drvdata(c);
+	if (!nd)
+		return 0;
+
+	if (nd->nd_state == NS_READY && nd->nd_ps_desc)
+		return snprintf(buf, PAGE_SIZE, "%s\n", nd->nd_ps_desc);
+	return 0;
+}
+static DEVICE_ATTR(description_info, 0600, dgrp_node_description_show, NULL);
+
+static ssize_t dgrp_node_hw_version_show(struct device *c,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct nd_struct *nd;
+
+	if (!c)
+		return 0;
+	nd = (struct nd_struct *) dev_get_drvdata(c);
+	if (!nd)
+		return 0;
+
+	if (nd->nd_state == NS_READY)
+		return snprintf(buf, PAGE_SIZE, "%d.%d\n",
+				(nd->nd_hw_ver >> 8) & 0xff,
+				nd->nd_hw_ver & 0xff);
+
+	return 0;
+}
+static DEVICE_ATTR(hw_version_info, 0600, dgrp_node_hw_version_show, NULL);
+
+static ssize_t dgrp_node_hw_id_show(struct device *c,
+				    struct device_attribute *attr, char *buf)
+{
+	struct nd_struct *nd;
+
+	if (!c)
+		return 0;
+	nd = (struct nd_struct *) dev_get_drvdata(c);
+	if (!nd)
+		return 0;
+
+
+	if (nd->nd_state == NS_READY)
+		return snprintf(buf, PAGE_SIZE, "%d\n", nd->nd_hw_id);
+	return 0;
+}
+static DEVICE_ATTR(hw_id_info, 0600, dgrp_node_hw_id_show, NULL);
+
+static ssize_t dgrp_node_sw_version_show(struct device *c,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct nd_struct *nd;
+
+	if (!c)
+		return 0;
+
+	nd = (struct nd_struct *) dev_get_drvdata(c);
+	if (!nd)
+		return 0;
+
+	if (nd->nd_state == NS_READY)
+		return snprintf(buf, PAGE_SIZE, "%d.%d\n",
+				(nd->nd_sw_ver >> 8) & 0xff,
+				nd->nd_sw_ver & 0xff);
+
+	return 0;
+}
+static DEVICE_ATTR(sw_version_info, 0600, dgrp_node_sw_version_show, NULL);
+
+
+static struct attribute *dgrp_sysfs_node_entries[] = {
+	&dev_attr_state.attr,
+	&dev_attr_description_info.attr,
+	&dev_attr_hw_version_info.attr,
+	&dev_attr_hw_id_info.attr,
+	&dev_attr_sw_version_info.attr,
+	NULL
+};
+
+
+static struct attribute_group dgrp_node_attribute_group = {
+	.name = NULL,
+	.attrs = dgrp_sysfs_node_entries,
+};
+
+
+void dgrp_create_node_class_sysfs_files(struct nd_struct *nd)
+{
+	int ret;
+	char name[10];
+
+	if (nd->nd_ID)
+		ID_TO_CHAR(nd->nd_ID, name);
+	else
+		sprintf(name, "node%ld", nd->nd_major);
+
+	nd->nd_class_dev = device_create(dgrp_class, dgrp_class_nodes_dev,
+		MKDEV(0, nd->nd_major), NULL, name);
+
+	ret = sysfs_create_group(&nd->nd_class_dev->kobj,
+				 &dgrp_node_attribute_group);
+
+	if (ret) {
+		pr_alert("%s: failed to create sysfs node device attributes.\n",
+			__func__);
+		sysfs_remove_group(&nd->nd_class_dev->kobj,
+				   &dgrp_node_attribute_group);
+		return;
+	}
+
+	dev_set_drvdata(nd->nd_class_dev, nd);
+
+}
+
+
+void dgrp_remove_node_class_sysfs_files(struct nd_struct *nd)
+{
+	if (nd->nd_class_dev) {
+		sysfs_remove_group(&nd->nd_class_dev->kobj,
+				   &dgrp_node_attribute_group);
+
+		device_destroy(dgrp_class, MKDEV(0, nd->nd_major));
+		nd->nd_class_dev = NULL;
+	}
+}
+
+
+
+static ssize_t dgrp_tty_state_show(struct device *d,
+				   struct device_attribute *attr, char *buf)
+{
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+
+	return snprintf(buf, PAGE_SIZE, "%s\n",
+			un->un_open_count ? "Open" : "Closed");
+}
+static DEVICE_ATTR(state_info, 0600, dgrp_tty_state_show, NULL);
+
+static ssize_t dgrp_tty_baud_show(struct device *d,
+				  struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%d\n",
+		un->un_open_count ? (PORTSERVER_DIVIDEND / ch->ch_s_brate) : 0);
+}
+static DEVICE_ATTR(baud_info, 0400, dgrp_tty_baud_show, NULL);
+
+
+static ssize_t dgrp_tty_msignals_show(struct device *d,
+				      struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+
+	if (ch->ch_open_count) {
+		return snprintf(buf, PAGE_SIZE, "%s %s %s %s %s %s\n",
+			(ch->ch_s_mlast & DM_RTS) ? "RTS" : "",
+			(ch->ch_s_mlast & DM_CTS) ? "CTS" : "",
+			(ch->ch_s_mlast & DM_DTR) ? "DTR" : "",
+			(ch->ch_s_mlast & DM_DSR) ? "DSR" : "",
+			(ch->ch_s_mlast & DM_CD) ? "DCD" : "",
+			(ch->ch_s_mlast & DM_RI)  ? "RI"  : "");
+	}
+	return 0;
+}
+static DEVICE_ATTR(msignals_info, 0400, dgrp_tty_msignals_show, NULL);
+
+
+static ssize_t dgrp_tty_iflag_show(struct device *d,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_s_iflag);
+}
+static DEVICE_ATTR(iflag_info, 0600, dgrp_tty_iflag_show, NULL);
+
+
+static ssize_t dgrp_tty_cflag_show(struct device *d,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_s_cflag);
+}
+static DEVICE_ATTR(cflag_info, 0600, dgrp_tty_cflag_show, NULL);
+
+
+static ssize_t dgrp_tty_oflag_show(struct device *d,
+				   struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_s_oflag);
+}
+static DEVICE_ATTR(oflag_info, 0600, dgrp_tty_oflag_show, NULL);
+
+
+static ssize_t dgrp_tty_digi_flag_show(struct device *d,
+				       struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%x\n", ch->ch_digi.digi_flags);
+}
+static DEVICE_ATTR(digi_flag_info, 0600, dgrp_tty_digi_flag_show, NULL);
+
+
+static ssize_t dgrp_tty_rxcount_show(struct device *d,
+				     struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%d\n", ch->ch_rxcount);
+}
+static DEVICE_ATTR(rxcount_info, 0600, dgrp_tty_rxcount_show, NULL);
+
+
+static ssize_t dgrp_tty_txcount_show(struct device *d,
+				     struct device_attribute *attr, char *buf)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	return snprintf(buf, PAGE_SIZE, "%d\n", ch->ch_txcount);
+}
+static DEVICE_ATTR(txcount_info, 0600, dgrp_tty_txcount_show, NULL);
+
+
+static ssize_t dgrp_tty_name_show(struct device *d,
+				  struct device_attribute *attr, char *buf)
+{
+	struct nd_struct *nd;
+	struct ch_struct *ch;
+	struct un_struct *un;
+	char name[10];
+
+	if (!d)
+		return 0;
+	un = (struct un_struct *) dev_get_drvdata(d);
+	if (!un)
+		return 0;
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+	nd = ch->ch_nd;
+	if (!nd)
+		return 0;
+
+	ID_TO_CHAR(nd->nd_ID, name);
+
+	return snprintf(buf, PAGE_SIZE, "%s%s%02d\n",
+		un->un_type == SERIAL_TYPE_XPRINT ? "pr" : "tty",
+		name, ch->ch_portnum);
+}
+static DEVICE_ATTR(custom_name, 0600, dgrp_tty_name_show, NULL);
+
+
+static struct attribute *dgrp_sysfs_tty_entries[] = {
+	&dev_attr_state_info.attr,
+	&dev_attr_baud_info.attr,
+	&dev_attr_msignals_info.attr,
+	&dev_attr_iflag_info.attr,
+	&dev_attr_cflag_info.attr,
+	&dev_attr_oflag_info.attr,
+	&dev_attr_digi_flag_info.attr,
+	&dev_attr_rxcount_info.attr,
+	&dev_attr_txcount_info.attr,
+	&dev_attr_custom_name.attr,
+	NULL
+};
+
+
+static struct attribute_group dgrp_tty_attribute_group = {
+	.name = NULL,
+	.attrs = dgrp_sysfs_tty_entries,
+};
+
+
+void dgrp_create_tty_sysfs(struct un_struct *un, struct device *c)
+{
+	int ret;
+
+	ret = sysfs_create_group(&c->kobj, &dgrp_tty_attribute_group);
+	if (ret) {
+		pr_alert("%s: failed to create sysfs tty device attributes.\n",
+			__func__);
+		sysfs_remove_group(&c->kobj, &dgrp_tty_attribute_group);
+		return;
+	}
+
+	dev_set_drvdata(c, un);
+
+}
+
+
+void dgrp_remove_tty_sysfs(struct device *c)
+{
+	sysfs_remove_group(&c->kobj, &dgrp_tty_attribute_group);
+}
diff --git a/drivers/staging/dgrp/dgrp_tty.c b/drivers/staging/dgrp/dgrp_tty.c
new file mode 100644
index 000000000000..7d7de873870c
--- /dev/null
+++ b/drivers/staging/dgrp/dgrp_tty.c
@@ -0,0 +1,3331 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     Gene Olson    <Gene_Olson at digi dot com>
+ *     James Puzzo   <jamesp at digi dot com>
+ *     Jeff Randall
+ *     Scott Kilau   <scottk at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/*
+ *
+ *  Filename:
+ *
+ *     dgrp_tty.c
+ *
+ *  Description:
+ *
+ *     This file implements the tty driver functionality for the
+ *     RealPort driver software.
+ *
+ *  Author:
+ *
+ *     James A. Puzzo
+ *     Ann-Marie Westgate
+ *
+ */
+
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/sched.h>
+
+#include "dgrp_common.h"
+
+#ifndef _POSIX_VDISABLE
+#define   _POSIX_VDISABLE ('\0')
+#endif
+
+/*
+ *	forward declarations
+ */
+
+static void drp_param(struct ch_struct *);
+static void dgrp_tty_close(struct tty_struct *, struct file *);
+
+/* ioctl helper functions */
+static int set_modem_info(struct ch_struct *, unsigned int, unsigned int *);
+static int get_modem_info(struct ch_struct *, unsigned int *);
+static void dgrp_set_custom_speed(struct ch_struct *, int);
+static int dgrp_tty_digigetedelay(struct tty_struct *, int *);
+static int dgrp_tty_digisetedelay(struct tty_struct *, int *);
+static int dgrp_send_break(struct ch_struct *, int);
+
+static ushort  tty_to_ch_flags(struct tty_struct *, char);
+static tcflag_t ch_to_tty_flags(unsigned short, char);
+
+static void dgrp_tty_input_start(struct tty_struct *);
+static void dgrp_tty_input_stop(struct tty_struct *);
+
+static void drp_wmove(struct ch_struct *, int, void*, int);
+
+static int dgrp_tty_open(struct tty_struct *, struct file *);
+static void dgrp_tty_close(struct tty_struct *, struct file *);
+static int dgrp_tty_write(struct tty_struct *, const unsigned char *, int);
+static int dgrp_tty_write_room(struct tty_struct *);
+static void dgrp_tty_flush_buffer(struct tty_struct *);
+static int dgrp_tty_chars_in_buffer(struct tty_struct *);
+static int dgrp_tty_ioctl(struct tty_struct *, unsigned int, unsigned long);
+static void dgrp_tty_set_termios(struct tty_struct *, struct ktermios *);
+static void dgrp_tty_stop(struct tty_struct *);
+static void dgrp_tty_start(struct tty_struct *);
+static void dgrp_tty_throttle(struct tty_struct *);
+static void dgrp_tty_unthrottle(struct tty_struct *);
+static void dgrp_tty_hangup(struct tty_struct *);
+static int dgrp_tty_put_char(struct tty_struct *, unsigned char);
+static int dgrp_tty_tiocmget(struct tty_struct *);
+static int dgrp_tty_tiocmset(struct tty_struct *, unsigned int, unsigned int);
+static int dgrp_tty_send_break(struct tty_struct *, int);
+static void dgrp_tty_send_xchar(struct tty_struct *, char);
+
+/*
+ *	tty defines
+ */
+#define	SERIAL_TYPE_NORMAL	1
+#define	SERIAL_TYPE_CALLOUT	2
+#define	SERIAL_TYPE_XPRINT	3
+
+
+/*
+ *	tty globals/statics
+ */
+
+
+#define PORTSERVER_DIVIDEND	1843200
+
+/*
+ *  Default transparent print information.
+ */
+static struct digi_struct digi_init = {
+	.digi_flags   = DIGI_COOK,	/* Flags			*/
+	.digi_maxcps  = 100,		/* Max CPS			*/
+	.digi_maxchar = 50,		/* Max chars in print queue	*/
+	.digi_bufsize = 100,		/* Printer buffer size		*/
+	.digi_onlen   = 4,		/* size of printer on string	*/
+	.digi_offlen  = 4,		/* size of printer off string	*/
+	.digi_onstr   = "\033[5i",	/* ANSI printer on string	*/
+	.digi_offstr  = "\033[4i",	/* ANSI printer off string	*/
+	.digi_term    = "ansi"		/* default terminal type	*/
+};
+
+/*
+ *	Define a local default termios struct. All ports will be created
+ *	with this termios initially.
+ *
+ *	This defines a raw port at 9600 baud, 8 data bits, no parity,
+ *	1 stop bit.
+ */
+static struct ktermios DefaultTermios = {
+	.c_iflag = (ICRNL | IXON),
+	.c_oflag = (OPOST | ONLCR),
+	.c_cflag = (B9600 | CS8 | CREAD | HUPCL | CLOCAL),
+	.c_lflag = (ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL
+		    | ECHOKE | IEXTEN),
+	.c_cc    = INIT_C_CC,
+	.c_line  = 0,
+};
+
+/* Define our tty operations struct */
+static const struct tty_operations dgrp_tty_ops = {
+	.open            = dgrp_tty_open,
+	.close           = dgrp_tty_close,
+	.write           = dgrp_tty_write,
+	.write_room      = dgrp_tty_write_room,
+	.flush_buffer    = dgrp_tty_flush_buffer,
+	.chars_in_buffer = dgrp_tty_chars_in_buffer,
+	.flush_chars     = NULL,
+	.ioctl           = dgrp_tty_ioctl,
+	.set_termios     = dgrp_tty_set_termios,
+	.stop            = dgrp_tty_stop,
+	.start           = dgrp_tty_start,
+	.throttle        = dgrp_tty_throttle,
+	.unthrottle      = dgrp_tty_unthrottle,
+	.hangup          = dgrp_tty_hangup,
+	.put_char        = dgrp_tty_put_char,
+	.tiocmget        = dgrp_tty_tiocmget,
+	.tiocmset        = dgrp_tty_tiocmset,
+	.break_ctl       = dgrp_tty_send_break,
+	.send_xchar      = dgrp_tty_send_xchar
+};
+
+
+static int calc_baud_rate(struct un_struct *un)
+{
+	int i;
+	int brate;
+
+	struct baud_rates {
+		unsigned int rate;
+		unsigned int cflag;
+	};
+
+	static struct baud_rates baud_rates[] = {
+		{ 921600, B921600 },
+		{ 460800, B460800 },
+		{ 230400, B230400 },
+		{ 115200, B115200 },
+		{  57600, B57600  },
+		{  38400, B38400  },
+		{  19200, B19200  },
+		{   9600, B9600   },
+		{   4800, B4800   },
+		{   2400, B2400   },
+		{   1200, B1200   },
+		{    600, B600    },
+		{    300, B300    },
+		{    200, B200    },
+		{    150, B150    },
+		{    134, B134    },
+		{    110, B110    },
+		{     75, B75     },
+		{     50, B50     },
+		{      0, B9600  }
+	};
+
+	brate = C_BAUD(un->un_tty);
+
+	for (i = 0; baud_rates[i].rate; i++) {
+		if (baud_rates[i].cflag == brate)
+			break;
+	}
+
+	return baud_rates[i].rate;
+}
+
+static int calc_fastbaud_rate(struct un_struct *un, struct ktermios *uts)
+{
+	int i;
+	int brate;
+
+	ulong bauds[2][16] = {
+		{ /* fastbaud*/
+			0,      57600,	 76800,	115200,
+			131657, 153600, 230400, 460800,
+			921600, 1200,   1800,	2400,
+			4800,   9600,	19200,	38400 },
+		{ /* fastbaud & CBAUDEX */
+			0,      57600,	115200,	230400,
+			460800, 150,    200,    921600,
+			600,    1200,   1800,	2400,
+			4800,   9600,	19200,	38400 }
+	};
+
+	brate = C_BAUD(un->un_tty) & 0xff;
+
+	i = (uts->c_cflag & CBAUDEX) ? 1 : 0;
+
+
+	if ((i >= 0) && (i < 2) && (brate >= 0) && (brate < 16))
+		brate = bauds[i][brate];
+	else
+		brate = 0;
+
+	return brate;
+}
+
+/**
+ * drp_param() -- send parameter values to be sent to the node
+ * @ch: channel structure of port to modify
+ *
+ * Interprets the tty and modem changes made by an application
+ * program (by examining the termios structures) and sets up
+ * parameter values to be sent to the node.
+ */
+static void drp_param(struct ch_struct *ch)
+{
+	struct nd_struct *nd;
+	struct un_struct *un;
+	int   brate;
+	int   mflow;
+	int   xflag;
+	int   iflag;
+	struct ktermios *tts, *pts, *uts;
+
+	nd = ch->ch_nd;
+
+	/*
+	 *  If the terminal device is open, use it to set up all tty
+	 *  modes and functions.  Otherwise use the printer device.
+	 */
+
+	if (ch->ch_tun.un_open_count) {
+
+		un = &ch->ch_tun;
+		tts = &ch->ch_tun.un_tty->termios;
+
+		/*
+		 *  If both devices are open, copy critical line
+		 *  parameters from the tty device to the printer,
+		 *  so that if the tty is closed, the printer will
+		 *  continue without disruption.
+		 */
+
+		if (ch->ch_pun.un_open_count) {
+
+			pts = &ch->ch_pun.un_tty->termios;
+
+			pts->c_cflag ^=
+				(pts->c_cflag ^ tts->c_cflag) &
+				(CBAUD  | CSIZE | CSTOPB | CREAD | PARENB |
+				 PARODD | HUPCL | CLOCAL);
+
+			pts->c_iflag ^=
+				(pts->c_iflag ^ tts->c_iflag) &
+				(IGNBRK | BRKINT | IGNPAR | PARMRK | INPCK |
+				 ISTRIP | IXON   | IXANY  | IXOFF);
+
+			pts->c_cc[VSTART] = tts->c_cc[VSTART];
+			pts->c_cc[VSTOP] = tts->c_cc[VSTOP];
+		}
+	} else if (ch->ch_pun.un_open_count == 0) {
+		pr_warn("%s - ch_pun.un_open_count shouldn't be 0\n",
+		       __func__);
+		return;
+	} else {
+		un = &ch->ch_pun;
+	}
+
+	uts = &un->un_tty->termios;
+
+	/*
+	 * Determine if FAST writes can be performed.
+	 */
+
+	if ((ch->ch_digi.digi_flags & DIGI_COOK) != 0 &&
+	    (ch->ch_tun.un_open_count != 0)  &&
+	    !((un->un_tty)->ldisc->ops->flags & LDISC_FLAG_DEFINED) &&
+	    !(L_XCASE(un->un_tty))) {
+		ch->ch_flag |= CH_FAST_WRITE;
+	} else {
+		ch->ch_flag &= ~CH_FAST_WRITE;
+	}
+
+	/*
+	 *  If FAST writes can be performed, and OPOST is on in the
+	 *  terminal device, do OPOST handling in the server.
+	 */
+
+	if ((ch->ch_flag & CH_FAST_WRITE) &&
+	      O_OPOST(un->un_tty) != 0) {
+		int oflag = tty_to_ch_flags(un->un_tty, 'o');
+
+		/* add to ch_ocook any processing flags set in the termio */
+		ch->ch_ocook |= oflag & (OF_OLCUC |
+					 OF_ONLCR |
+					 OF_OCRNL |
+					 OF_ONLRET |
+					 OF_TABDLY);
+
+		/*
+		 * the hpux driver clears any flags set in ch_ocook
+		 * from the termios oflag.  It is STILL reported though
+		 * by a TCGETA
+		 */
+
+		oflag = ch_to_tty_flags(ch->ch_ocook, 'o');
+		uts->c_oflag &= ~oflag;
+
+	} else {
+		/* clear the ch->ch_ocook flag */
+		int oflag = ch_to_tty_flags(ch->ch_ocook, 'o');
+		uts->c_oflag |= oflag;
+		ch->ch_ocook = 0;
+	}
+
+	ch->ch_oflag = ch->ch_ocook;
+
+
+	ch->ch_flag &= ~CH_FAST_READ;
+
+	/*
+	 *  Generate channel flags
+	 */
+
+	if (C_BAUD(un->un_tty) == B0) {
+		if (!(ch->ch_flag & CH_BAUD0)) {
+			/* TODO : the HPUX driver flushes line */
+			/* TODO : discipline, I assume I don't have to */
+
+			ch->ch_tout = ch->ch_tin;
+			ch->ch_rout = ch->ch_rin;
+
+			ch->ch_break_time = 0;
+
+			ch->ch_send |= RR_TX_FLUSH | RR_RX_FLUSH;
+
+			ch->ch_mout &= ~(DM_DTR | DM_RTS);
+
+			ch->ch_flag |= CH_BAUD0;
+		}
+	} else if (ch->ch_custom_speed) {
+		ch->ch_brate = PORTSERVER_DIVIDEND / ch->ch_custom_speed ;
+
+		if (ch->ch_flag & CH_BAUD0) {
+			ch->ch_mout |= DM_DTR | DM_RTS;
+
+			ch->ch_flag &= ~CH_BAUD0;
+		}
+	} else {
+		/*
+		 * Baud rate mapping.
+		 *
+		 * If FASTBAUD isn't on, we can scan the new baud rate list
+		 * as required.
+		 *
+		 * However, if FASTBAUD is on, we must go to the old
+		 * baud rate mapping that existed many many moons ago,
+		 * for compatibility reasons.
+		 */
+
+		if (!(ch->ch_digi.digi_flags & DIGI_FAST))
+			brate = calc_baud_rate(un);
+		else
+			brate = calc_fastbaud_rate(un, uts);
+
+		if (brate == 0)
+			brate = 9600;
+
+		ch->ch_brate = PORTSERVER_DIVIDEND / brate;
+
+		if (ch->ch_flag & CH_BAUD0) {
+			ch->ch_mout |= DM_DTR | DM_RTS;
+
+			ch->ch_flag &= ~CH_BAUD0;
+		}
+	}
+
+	/*
+	 *  Generate channel cflags from the termio.
+	 */
+
+	ch->ch_cflag = tty_to_ch_flags(un->un_tty, 'c');
+
+	/*
+	 *  Generate channel iflags from the termio.
+	 */
+
+	iflag = (int) tty_to_ch_flags(un->un_tty, 'i');
+
+	if (START_CHAR(un->un_tty) == _POSIX_VDISABLE ||
+	    STOP_CHAR(un->un_tty) == _POSIX_VDISABLE) {
+		iflag &= ~(IF_IXON | IF_IXANY | IF_IXOFF);
+	}
+
+	ch->ch_iflag = iflag;
+
+	/*
+	 *  Generate flow control characters
+	 */
+
+	/*
+	 * From the POSIX.1 spec (7.1.2.6): "If {_POSIX_VDISABLE}
+	 * is defined for the terminal device file, and the value
+	 * of one of the changable special control characters (see
+	 * 7.1.1.9) is {_POSIX_VDISABLE}, that function shall be
+	 * disabled, that is, no input data shall be recognized as
+	 * the disabled special character."
+	 *
+	 * OK, so we don't ever assign S/DXB XON or XOFF to _POSIX_VDISABLE.
+	 */
+
+	if (uts->c_cc[VSTART] != _POSIX_VDISABLE)
+		ch->ch_xon = uts->c_cc[VSTART];
+	if (uts->c_cc[VSTOP] != _POSIX_VDISABLE)
+		ch->ch_xoff = uts->c_cc[VSTOP];
+
+	ch->ch_lnext = (uts->c_cc[VLNEXT] == _POSIX_VDISABLE ? 0 :
+			uts->c_cc[VLNEXT]);
+
+	/*
+	 * Also, if either c_cc[START] or c_cc[STOP] is set to
+	 * _POSIX_VDISABLE, we can't really do software flow
+	 * control--in either direction--so we turn it off as
+	 * far as S/DXB is concerned.  In essence, if you disable
+	 * one, you disable the other too.
+	 */
+	if ((uts->c_cc[VSTART] == _POSIX_VDISABLE) ||
+	    (uts->c_cc[VSTOP] == _POSIX_VDISABLE))
+		ch->ch_iflag &= ~(IF_IXOFF | IF_IXON);
+
+	/*
+	 *  Update xflags.
+	 */
+
+	xflag = 0;
+
+	if (ch->ch_digi.digi_flags & DIGI_AIXON)
+		xflag = XF_XIXON;
+
+	if ((ch->ch_xxon == _POSIX_VDISABLE) ||
+	    (ch->ch_xxoff == _POSIX_VDISABLE))
+		xflag &= ~XF_XIXON;
+
+	ch->ch_xflag = xflag;
+
+
+	/*
+	 *  Figure effective DCD value.
+	 */
+
+	if (C_CLOCAL(un->un_tty))
+		ch->ch_flag |= CH_CLOCAL;
+	else
+		ch->ch_flag &= ~CH_CLOCAL;
+
+	/*
+	 *  Check modem signals
+	 */
+
+	dgrp_carrier(ch);
+
+	/*
+	 *  Get hardware handshake value.
+	 */
+
+	mflow = 0;
+
+	if (C_CRTSCTS(un->un_tty))
+		mflow |= (DM_RTS | DM_CTS);
+
+	if (ch->ch_digi.digi_flags & RTSPACE)
+		mflow |= DM_RTS;
+
+	if (ch->ch_digi.digi_flags & DTRPACE)
+		mflow |= DM_DTR;
+
+	if (ch->ch_digi.digi_flags & CTSPACE)
+		mflow |= DM_CTS;
+
+	if (ch->ch_digi.digi_flags & DSRPACE)
+		mflow |= DM_DSR;
+
+	if (ch->ch_digi.digi_flags & DCDPACE)
+		mflow |= DM_CD;
+
+	if (ch->ch_digi.digi_flags & DIGI_RTS_TOGGLE)
+		mflow |= DM_RTS_TOGGLE;
+
+	ch->ch_mflow = mflow;
+
+	/*
+	 *  Send the changes to the server.
+	 */
+
+	ch->ch_flag |= CH_PARAM;
+	(ch->ch_nd)->nd_tx_work = 1;
+
+	if (waitqueue_active(&ch->ch_flag_wait))
+		wake_up_interruptible(&ch->ch_flag_wait);
+}
+
+/*
+ * This function is just used as a callback for timeouts
+ * waiting on the ch_sleep flag.
+ */
+static void wake_up_drp_sleep_timer(unsigned long ptr)
+{
+	struct ch_struct *ch = (struct ch_struct *) ptr;
+	if (ch)
+		wake_up(&ch->ch_sleep);
+}
+
+
+/*
+ * Set up our own sleep that can't be cancelled
+ * until our timeout occurs.
+ */
+static void drp_my_sleep(struct ch_struct *ch)
+{
+	struct timer_list drp_wakeup_timer;
+	DECLARE_WAITQUEUE(wait, current);
+
+	/*
+	 * First make sure we're ready to receive the wakeup.
+	 */
+
+	add_wait_queue(&ch->ch_sleep, &wait);
+	current->state = TASK_UNINTERRUPTIBLE;
+
+	/*
+	 * Since we are uninterruptible, set a timer to
+	 * unset the uninterruptable state in 1 second.
+	 */
+
+	init_timer(&drp_wakeup_timer);
+	drp_wakeup_timer.function = wake_up_drp_sleep_timer;
+	drp_wakeup_timer.data = (unsigned long) ch;
+	drp_wakeup_timer.expires = jiffies + (1 * HZ);
+	add_timer(&drp_wakeup_timer);
+
+	schedule();
+
+	del_timer(&drp_wakeup_timer);
+
+	remove_wait_queue(&ch->ch_sleep, &wait);
+}
+
+/*
+ * dgrp_tty_open()
+ *
+ * returns:
+ *    -EBUSY    - this is a callout device and the normal device is active
+ *              - there is an error in opening the tty
+ *    -ENODEV   - the channel does not exist
+ *    -EAGAIN   - we are in the middle of hanging up or closing
+ *              - IMMEDIATE_OPEN fails
+ *    -ENXIO or -EAGAIN
+ *              - if the port is outside physical range
+ *    -EINTR    - the open is interrupted
+ *
+ */
+static int dgrp_tty_open(struct tty_struct *tty, struct file *file)
+{
+	int    retval = 0;
+	struct nd_struct  *nd;
+	struct ch_struct *ch;
+	struct un_struct  *un;
+	int    port;
+	int    delay_error;
+	int    otype;
+	int    unf;
+	int    wait_carrier;
+	int    category;
+	int    counts_were_incremented = 0;
+	ulong lock_flags;
+	DECLARE_WAITQUEUE(wait, current);
+
+	/*
+	 * Do some initial checks to see if the node and port exist
+	 */
+
+	nd = nd_struct_get(MAJOR(tty_devnum(tty)));
+	port = PORT_NUM(MINOR(tty_devnum(tty)));
+	category = OPEN_CATEGORY(MINOR(tty_devnum(tty)));
+
+	if (!nd)
+		return -ENODEV;
+
+	if (port >= CHAN_MAX)
+		return -ENODEV;
+
+	/*
+	 *  The channel exists.
+	 */
+
+	ch = nd->nd_chan + port;
+
+	un = IS_PRINT(MINOR(tty_devnum(tty))) ? &ch->ch_pun : &ch->ch_tun;
+	un->un_tty = tty;
+	tty->driver_data = un;
+
+	/*
+	 * If we are in the middle of hanging up,
+	 * then return an error
+	 */
+	if (tty_hung_up_p(file)) {
+		retval = ((un->un_flag & UN_HUP_NOTIFY) ?
+			   -EAGAIN : -ERESTARTSYS);
+		goto done;
+	}
+
+	/*
+	 * If the port is in the middle of closing, then block
+	 * until it is done, then try again.
+	 */
+	retval = wait_event_interruptible(un->un_close_wait,
+			((un->un_flag & UN_CLOSING) == 0));
+
+	if (retval)
+		goto done;
+
+	/*
+	 * If the port is in the middle of a reopen after a network disconnect,
+	 * wait until it is done, then try again.
+	 */
+	retval = wait_event_interruptible(ch->ch_flag_wait,
+			((ch->ch_flag & CH_PORT_GONE) == 0));
+
+	if (retval)
+		goto done;
+
+	/*
+	 * If this is a callout device, then just make sure the normal
+	 * device isn't being used.
+	 */
+
+	if (tty->driver->subtype == SERIAL_TYPE_CALLOUT) {
+		if (un->un_flag & UN_NORMAL_ACTIVE) {
+			retval = -EBUSY;
+			goto done;
+		} else {
+			un->un_flag |= UN_CALLOUT_ACTIVE;
+		}
+	}
+
+	/*
+	 *  Loop waiting until the open can be successfully completed.
+	 */
+
+	spin_lock_irqsave(&nd->nd_lock, lock_flags);
+
+	nd->nd_tx_work = 1;
+
+	for (;;) {
+		wait_carrier = 0;
+
+		/*
+		 * Determine the open type from the flags provided.
+		 */
+
+		/*
+		 * If the port is not enabled, then exit
+		 */
+		if (test_bit(TTY_IO_ERROR, &tty->flags)) {
+			/* there was an error in opening the tty */
+			if (un->un_flag & UN_CALLOUT_ACTIVE)
+				retval = -EBUSY;
+			else
+				un->un_flag |= UN_NORMAL_ACTIVE;
+			goto unlock;
+		}
+
+		if (file->f_flags & O_NONBLOCK) {
+
+			/*
+			 * if the O_NONBLOCK is set, errors on read and write
+			 * must return -EAGAIN immediately and NOT sleep
+			 * on the waitqs.
+			 */
+			otype = OTYPE_IMMEDIATE;
+			delay_error = -EAGAIN;
+
+		} else if (!OPEN_WAIT_AVAIL(category) ||
+			  (file->f_flags & O_NDELAY) != 0) {
+			otype = OTYPE_IMMEDIATE;
+			delay_error = -EBUSY;
+
+		} else if (!OPEN_WAIT_CARRIER(category) ||
+			  ((ch->ch_digi.digi_flags & DIGI_FORCEDCD) != 0) ||
+			  C_CLOCAL(tty)) {
+			otype = OTYPE_PERSISTENT;
+			delay_error = 0;
+
+		} else {
+			otype = OTYPE_INCOMING;
+			delay_error = 0;
+		}
+
+		/*
+		 * Handle port currently outside physical port range.
+		 */
+
+		if (port >= nd->nd_chan_count) {
+			if (otype == OTYPE_IMMEDIATE) {
+				retval = (nd->nd_state == NS_READY) ?
+						-ENXIO : -EAGAIN;
+				goto unlock;
+			}
+		}
+
+		/*
+		 *  Handle port not currently open.
+		 */
+
+		else if (ch->ch_open_count == 0) {
+			/*
+			 * Return an error when an Incoming Open
+			 * response indicates the port is busy.
+			 */
+
+			if (ch->ch_open_error != 0 && otype == ch->ch_otype) {
+				retval = (ch->ch_open_error <= 2) ?
+					  delay_error : -ENXIO ;
+				goto unlock;
+			}
+
+			/*
+			 * Fail any new Immediate open if we do not have
+			 * a normal connection to the server.
+			 */
+
+			if (nd->nd_state != NS_READY &&
+			    otype == OTYPE_IMMEDIATE) {
+				retval = -EAGAIN;
+				goto unlock;
+			}
+
+			/*
+			 * If a Realport open of the correct type has
+			 * succeeded, complete the open.
+			 */
+
+			if (ch->ch_state == CS_READY && ch->ch_otype == otype)
+				break;
+		}
+
+		/*
+		 * Handle port already open and active as a device
+		 * of same category.
+		 */
+
+		else if ((ch->ch_category == category) ||
+			  IS_PRINT(MINOR(tty_devnum(tty)))) {
+			/*
+			 * Fail if opening the device now would
+			 * violate exclusive use.
+			 */
+			unf = ch->ch_tun.un_flag | ch->ch_pun.un_flag;
+
+			if ((file->f_flags & O_EXCL) || (unf & UN_EXCL)) {
+				retval = -EBUSY;
+				goto unlock;
+			}
+
+			/*
+			 * If the open device is in the hangup state, all
+			 * system calls fail except close().
+			 */
+
+			/* TODO : check on hangup_p calls */
+
+			if (ch->ch_flag & CH_HANGUP) {
+				retval = -ENXIO;
+				goto unlock;
+			}
+
+			/*
+			 * If the port is ready, and carrier is ignored
+			 * or present, then complete the open.
+			 */
+
+			if (ch->ch_state == CS_READY &&
+			    (otype != OTYPE_INCOMING ||
+			    ch->ch_flag & CH_VIRT_CD))
+				break;
+
+			wait_carrier = 1;
+		}
+
+		/*
+		 *  Handle port active with a different category device.
+		 */
+
+		else {
+			if (otype == OTYPE_IMMEDIATE) {
+				retval = delay_error;
+				goto unlock;
+			}
+		}
+
+		/*
+		 * Wait until conditions change, then take another
+		 * try at the open.
+		 */
+
+		ch->ch_wait_count[otype]++;
+
+		if (wait_carrier)
+			ch->ch_wait_carrier++;
+
+		/*
+		 * Prepare the task to accept the wakeup, then
+		 * release our locks and release control.
+		 */
+
+		add_wait_queue(&ch->ch_flag_wait, &wait);
+		current->state = TASK_INTERRUPTIBLE;
+
+		spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+
+		/*
+		 * Give up control, we'll come back if we're
+		 * interrupted or are woken up.
+		 */
+		schedule();
+		remove_wait_queue(&ch->ch_flag_wait, &wait);
+
+		spin_lock_irqsave(&nd->nd_lock, lock_flags);
+
+		current->state = TASK_RUNNING;
+
+		ch->ch_wait_count[otype]--;
+
+		if (wait_carrier)
+			ch->ch_wait_carrier--;
+
+		nd->nd_tx_work = 1;
+
+		if (signal_pending(current)) {
+			retval = -EINTR;
+			goto unlock;
+		}
+	} /* end for(;;) */
+
+	/*
+	 *  The open has succeeded.  No turning back.
+	 */
+	counts_were_incremented = 1;
+	un->un_open_count++;
+	ch->ch_open_count++;
+
+	/*
+	 * Initialize the channel, if it's not already open.
+	 */
+
+	if (ch->ch_open_count == 1) {
+		ch->ch_flag = 0;
+		ch->ch_inwait = 0;
+		ch->ch_category = category;
+		ch->ch_pscan_state = 0;
+
+		/* TODO : find out what PS-1 bug Gene was referring to */
+		/* TODO : in the following comment. */
+
+		ch->ch_send = RR_TX_START | RR_RX_START;  /* PS-1 bug */
+
+		if (C_CLOCAL(tty) ||
+		    ch->ch_s_mlast & DM_CD ||
+		    ch->ch_digi.digi_flags & DIGI_FORCEDCD)
+			ch->ch_flag |= CH_VIRT_CD;
+		else if (OPEN_FORCES_CARRIER(category))
+			ch->ch_flag |= CH_VIRT_CD;
+
+	}
+
+	/*
+	 *  Initialize the unit, if it is not already open.
+	 */
+
+	if (un->un_open_count == 1) {
+		/*
+		 *  Since all terminal options are always sticky in Linux,
+		 *  we don't need the UN_STICKY flag to be handled specially.
+		 */
+		/* clears all the digi flags, leaves serial flags */
+		un->un_flag &= ~UN_DIGI_MASK;
+
+		if (file->f_flags & O_EXCL)
+			un->un_flag |= UN_EXCL;
+
+		/* TODO : include "session" and "pgrp" */
+
+		/*
+		 *  In Linux, all terminal parameters are intended to be sticky.
+		 *  as a result, we "remove" the code which once reset the ports
+		 *  to sane values.
+		 */
+
+		drp_param(ch);
+
+	}
+
+	un->un_flag |= UN_INITIALIZED;
+
+	retval = 0;
+
+unlock:
+
+	spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+
+done:
+	/*
+	 * Linux does a close for every open, even failed ones!
+	 */
+	if (!counts_were_incremented) {
+		un->un_open_count++;
+		ch->ch_open_count++;
+	}
+
+	if (retval)
+		dev_err(tty->dev, "tty open bad return (%i)\n", retval);
+
+	return retval;
+}
+
+
+
+
+/*
+ * dgrp_tty_close() -- close function for tty_operations
+ */
+static void dgrp_tty_close(struct tty_struct *tty, struct file *file)
+{
+	struct ch_struct *ch;
+	struct un_struct *un;
+	struct nd_struct *nd;
+	int	tpos;
+	int	port;
+	int	err = 0;
+	int	s = 0;
+	ulong  waketime;
+	ulong  lock_flags;
+	int sent_printer_offstr = 0;
+
+	port = PORT_NUM(MINOR(tty_devnum(tty)));
+
+	un = tty->driver_data;
+
+	if (!un)
+		return;
+
+	ch = un->un_ch;
+
+	if (!ch)
+		return;
+
+	nd = ch->ch_nd;
+
+	if (!nd)
+		return;
+
+	spin_lock_irqsave(&nd->nd_lock, lock_flags);
+
+
+	/* Used to be on channel basis, now we check on a unit basis. */
+	if (un->un_open_count != 1)
+		goto unlock;
+
+	/*
+	 * OK, its the last close on the unit
+	 */
+	un->un_flag |= UN_CLOSING;
+
+	/*
+	 * Notify the discipline to only process XON/XOFF characters.
+	 */
+	tty->closing = 1;
+
+	/*
+	 * Wait for output to drain only if this is
+	 * the last close against the channel
+	 */
+
+	if (ch->ch_open_count == 1) {
+		/*
+		 * If its the print device, we need to ensure at all costs that
+		 * the offstr will fit. If it won't, flush our tbuf.
+		 */
+		if (IS_PRINT(MINOR(tty_devnum(tty))) &&
+		    (((ch->ch_tout - ch->ch_tin - 1) & TBUF_MASK) <
+		    ch->ch_digi.digi_offlen))
+			ch->ch_tin = ch->ch_tout;
+
+		/*
+		 * Turn off the printer.  Don't bother checking to see if its
+		 * IS_PRINT... Since this is the last close the flag is going
+		 * to be cleared, so we MUST make sure the offstr gets inserted
+		 * into tbuf.
+		 */
+
+		if ((ch->ch_flag & CH_PRON) != 0) {
+			drp_wmove(ch, 0, ch->ch_digi.digi_offstr,
+				  ch->ch_digi.digi_offlen);
+			ch->ch_flag &= ~CH_PRON;
+			sent_printer_offstr = 1;
+		}
+	}
+
+	/*
+	 *  Wait until either the output queue has drained, or we see
+	 *  absolutely no progress for 15 seconds.
+	 */
+
+	tpos = ch->ch_s_tpos;
+
+	waketime = jiffies + 15 * HZ;
+
+	for (;;) {
+
+		/*
+		 *  Make sure the port still exists.
+		 */
+
+		if (port >= nd->nd_chan_count) {
+			err = 1;
+			break;
+		}
+
+		if (signal_pending(current)) {
+			err = 1;
+			break;
+		}
+
+		/*
+		 * If the port is idle (not opened on the server), we have
+		 * no way of draining/flushing/closing the port on that server.
+		 * So break out of loop.
+		 */
+		if (ch->ch_state == CS_IDLE)
+			break;
+
+		nd->nd_tx_work = 1;
+
+		/*
+		 *  Exit if the queues for this unit are empty,
+		 *  and either the other unit is still open or all
+		 *  data has drained.
+		 */
+
+		if ((un->un_tty)->ops->chars_in_buffer ?
+		    ((un->un_tty)->ops->chars_in_buffer)(un->un_tty) == 0 : 1) {
+
+			/*
+			 * We don't need to wait for a buffer to drain
+			 * if the other unit is open.
+			 */
+
+			if (ch->ch_open_count != un->un_open_count)
+				break;
+
+			/*
+			 *  The wait is complete when all queues are
+			 *  drained, and any break in progress is complete.
+			 */
+
+			if (ch->ch_tin == ch->ch_tout &&
+			    ch->ch_s_tin == ch->ch_s_tpos &&
+			    (ch->ch_send & RR_TX_BREAK) == 0) {
+				break;
+			}
+		}
+
+		/*
+		 * Flush TX data and exit the wait if NDELAY is set,
+		 * or this is not a DIGI printer, and the close timeout
+		 * expires.
+		 */
+
+		if ((file->f_flags & (O_NDELAY | O_NONBLOCK)) ||
+		    ((long)(jiffies - waketime) >= 0 &&
+		      (ch->ch_digi.digi_flags & DIGI_PRINTER) == 0)) {
+
+				/*
+				 * If we sent the printer off string, we cannot
+				 * flush our internal buffers, or we might lose
+				 * the offstr.
+				 */
+				if (!sent_printer_offstr)
+					dgrp_tty_flush_buffer(tty);
+
+				tty_ldisc_flush(tty);
+				break;
+		}
+
+		/*
+		 *  Otherwise take a short nap.
+		 */
+
+		ch->ch_flag |= CH_DRAIN;
+
+		spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+
+		schedule_timeout_interruptible(1);
+		s = signal_pending(current);
+
+		spin_lock_irqsave(&nd->nd_lock, lock_flags);
+
+		if (s) {
+			/*
+			 * If we had sent the printer off string, we now have
+			 * some problems.
+			 *
+			 * The system won't let us sleep since we got an error
+			 * back from sleep, presumably because the user did
+			 * a ctrl-c...
+			 * But we need to ensure that the offstr gets sent!
+			 * Thus, we have to do something else besides sleeping.
+			 * The plan:
+			 * 1) Make this task uninterruptable.
+			 * 2) Set up a timer to go off in 1 sec.
+			 * 3) Act as tho we just got out of the sleep above.
+			 *
+			 * Thankfully, in the real world, this just
+			 * never happens.
+			 */
+
+			if (sent_printer_offstr) {
+				spin_unlock_irqrestore(&nd->nd_lock,
+						       lock_flags);
+				drp_my_sleep(ch);
+				spin_lock_irqsave(&nd->nd_lock, lock_flags);
+			} else {
+				err = 1;
+				break;
+			}
+		}
+
+		/*
+		 *  Restart the wait if any progress is seen.
+		 */
+
+		if (ch->ch_s_tpos != tpos) {
+			tpos = ch->ch_s_tpos;
+
+			/* TODO:  this gives us timeout problems with nist ?? */
+			waketime = jiffies + 15 * HZ;
+		}
+	}
+
+	/*
+	 *  Close the line discipline
+	 */
+
+	/* this is done in tty_io.c */
+	/* if ((un->un_tty)->ldisc.close)
+	 *	((un->un_tty)->ldisc.close)(un->un_tty);
+	 */
+
+	/* don't do this here */
+	/* un->un_flag = 0; */
+
+	/*
+	 *  Flush the receive buffer on terminal unit close only.
+	 */
+
+	if (!IS_PRINT(MINOR(tty_devnum(tty))))
+		ch->ch_rout = ch->ch_rin;
+
+
+	/*
+	 * Don't permit the close to happen until we get any pending
+	 * sync request responses.
+	 * There could be other ports depending upon the response as well.
+	 *
+	 * Also, don't permit the close to happen until any parameter
+	 * changes have been sent out from the state machine as well.
+	 * This is required because of a ditty -a race with -HUPCL
+	 * We MUST make sure all channel parameters have been sent to the
+	 * Portserver before sending a close.
+	 */
+
+	if ((err != 1) && (ch->ch_state != CS_IDLE)) {
+		spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+		s = wait_event_interruptible(ch->ch_flag_wait,
+			((ch->ch_flag & (CH_WAITING_SYNC | CH_PARAM)) == 0));
+		spin_lock_irqsave(&nd->nd_lock, lock_flags);
+	}
+
+	/*
+	 * Cleanup the channel if last unit open.
+	 */
+
+	if (ch->ch_open_count == 1) {
+		ch->ch_flag = 0;
+		ch->ch_category = 0;
+		ch->ch_send = 0;
+		ch->ch_expect = 0;
+		ch->ch_tout = ch->ch_tin;
+		/* (un->un_tty)->device = 0; */
+
+		if (ch->ch_state == CS_READY)
+			ch->ch_state = CS_SEND_CLOSE;
+	}
+
+	/*
+	 * Send the changes to the server
+	 */
+	if (ch->ch_state != CS_IDLE) {
+		ch->ch_flag |= CH_PARAM;
+		wake_up_interruptible(&ch->ch_flag_wait);
+	}
+
+	nd->nd_tx_work = 1;
+	nd->nd_tx_ready = 1;
+
+unlock:
+	tty->closing = 0;
+
+	if (ch->ch_open_count <= 0)
+		dev_info(tty->dev,
+			 "%s - unexpected value for ch->ch_open_count: %i\n",
+			 __func__, ch->ch_open_count);
+	else
+		ch->ch_open_count--;
+
+	if (un->un_open_count <= 0)
+		dev_info(tty->dev,
+			 "%s - unexpected value for un->un_open_count: %i\n",
+			 __func__, un->un_open_count);
+	else
+		un->un_open_count--;
+
+	un->un_flag &= ~(UN_NORMAL_ACTIVE | UN_CALLOUT_ACTIVE | UN_CLOSING);
+	if (waitqueue_active(&un->un_close_wait))
+		wake_up_interruptible(&un->un_close_wait);
+
+	spin_unlock_irqrestore(&nd->nd_lock, lock_flags);
+
+	return;
+
+}
+
+static void drp_wmove(struct ch_struct *ch, int from_user, void *buf, int count)
+{
+	int n;
+	int ret = 0;
+
+	ch->ch_nd->nd_tx_work = 1;
+
+	n = TBUF_MAX - ch->ch_tin;
+
+	if (count >= n) {
+		if (from_user)
+			ret = copy_from_user(ch->ch_tbuf + ch->ch_tin,
+					     (void __user *) buf, n);
+		else
+			memcpy(ch->ch_tbuf + ch->ch_tin, buf, n);
+
+		buf = (char *) buf + n;
+		count -= n;
+		ch->ch_tin = 0;
+	}
+
+	if (from_user)
+		ret = copy_from_user(ch->ch_tbuf + ch->ch_tin,
+				     (void __user *) buf, count);
+	else
+		memcpy(ch->ch_tbuf + ch->ch_tin, buf, count);
+
+	ch->ch_tin += count;
+}
+
+
+static int dgrp_calculate_txprint_bounds(struct ch_struct *ch, int space,
+					 int *un_flag)
+{
+	clock_t tt;
+	clock_t mt;
+	unsigned short tmax = 0;
+
+	/*
+	 * If the terminal device is busy, reschedule when
+	 * the terminal device becomes idle.
+	 */
+
+	if (ch->ch_tun.un_open_count != 0 &&
+	    ch->ch_tun.un_tty->ops->chars_in_buffer &&
+	    ((ch->ch_tun.un_tty->ops->chars_in_buffer)(ch->ch_tun.un_tty) != 0)) {
+		*un_flag = UN_PWAIT;
+		return 0;
+	}
+
+	/*
+	 * Assure that whenever there is printer data in the output
+	 * buffer, there always remains enough space after it to
+	 * turn the printer off.
+	 */
+	space -= ch->ch_digi.digi_offlen;
+
+	if (space <= 0) {
+		*un_flag = UN_EMPTY;
+		return 0;
+	}
+
+	/*
+	 * We measure printer CPS speed by incrementing
+	 * ch_cpstime by (HZ / digi_maxcps) for every
+	 * character we output, restricting output so
+	 * that ch_cpstime never exceeds lbolt.
+	 *
+	 * However if output has not been done for some
+	 * time, lbolt will grow to very much larger than
+	 * ch_cpstime, which would allow essentially
+	 * unlimited amounts of output until ch_cpstime
+	 * finally caught up.   To avoid this, we adjust
+	 * cps_time when necessary so the difference
+	 * between lbolt and ch_cpstime never results
+	 * in sending more than digi_bufsize characters.
+	 *
+	 * This nicely models a printer with an internal
+	 * buffer of digi_bufsize characters.
+	 *
+	 * Get the time between lbolt and ch->ch_cpstime;
+	 */
+
+	tt = jiffies - ch->ch_cpstime;
+
+	/*
+	 * Compute the time required to send digi_bufsize
+	 * characters.
+	 */
+
+	mt = HZ * ch->ch_digi.digi_bufsize / ch->ch_digi.digi_maxcps;
+
+	/*
+	 * Compute the number of characters that can be sent
+	 * without violating the time constraint.   If the
+	 * direct calculation of this number is bigger than
+	 * digi_bufsize, limit the number to digi_bufsize,
+	 * and adjust cpstime to match.
+	 */
+
+	if ((clock_t)(tt + HZ) > (clock_t)(mt + HZ)) {
+		tmax = ch->ch_digi.digi_bufsize;
+		ch->ch_cpstime = jiffies - mt;
+	} else {
+		tmax = ch->ch_digi.digi_maxcps * tt / HZ;
+	}
+
+	/*
+	 * If the time constraint now binds, limit the transmit
+	 * count accordingly, and tentatively arrange to be
+	 * rescheduled based on time.
+	 */
+
+	if (tmax < space) {
+		*un_flag = UN_TIME;
+		space = tmax;
+	}
+
+	/*
+	 * Compute the total number of characters we can
+	 * output before the total number of characters known
+	 * to be in the output queue exceeds digi_maxchar.
+	 */
+
+	tmax = (ch->ch_digi.digi_maxchar -
+		((ch->ch_tin - ch->ch_tout) & TBUF_MASK) -
+		((ch->ch_s_tin - ch->ch_s_tpos) & 0xffff));
+
+
+	/*
+	 * If the digi_maxchar constraint now holds, limit
+	 * the transmit count accordingly, and arrange to
+	 * be rescheduled when the queue becomes empty.
+	 */
+
+	if (space > tmax) {
+		*un_flag = UN_EMPTY;
+		space = tmax;
+	}
+
+	if (space <= 0)
+		*un_flag |= UN_EMPTY;
+
+	return space;
+}
+
+
+static int dgrp_tty_write(struct tty_struct *tty,
+			  const unsigned char *buf,
+			  int count)
+{
+	struct nd_struct *nd;
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int	space;
+	int	n;
+	int	t;
+	int sendcount;
+	int un_flag;
+	ulong lock_flags;
+
+	if (tty == NULL)
+		return 0;
+
+	un = tty->driver_data;
+	if (!un)
+		return 0;
+
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+
+	nd = ch->ch_nd;
+	if (!nd)
+		return 0;
+
+	/*
+	 * Ignore the request if the channel is not ready.
+	 */
+	if (ch->ch_state != CS_READY)
+		return 0;
+
+	spin_lock_irqsave(&dgrp_poll_data.poll_lock, lock_flags);
+
+	/*
+	 * Ignore the request if output is blocked.
+	 */
+	if ((un->un_flag & (UN_EMPTY | UN_LOW | UN_TIME | UN_PWAIT)) != 0) {
+		count = 0;
+		goto out;
+	}
+
+	/*
+	 * Also ignore the request if DPA has this port open,
+	 * and is flow controlled on reading more data.
+	 */
+	if (nd->nd_dpa_debug && nd->nd_dpa_flag & DPA_WAIT_SPACE &&
+		nd->nd_dpa_port == MINOR(tty_devnum(ch->ch_tun.un_tty))) {
+		count = 0;
+		goto out;
+	}
+
+	/*
+	 *	Limit amount we will write to the amount of space
+	 *	available in the channel buffer.
+	 */
+	sendcount = 0;
+
+	space = (ch->ch_tout - ch->ch_tin - 1) & TBUF_MASK;
+
+	/*
+	 * Handle the printer device.
+	 */
+
+	un_flag = UN_LOW;
+
+	if (IS_PRINT(MINOR(tty_devnum(tty)))) {
+		clock_t tt;
+		clock_t mt;
+		unsigned short tmax = 0;
+
+		/*
+		 * If the terminal device is busy, reschedule when
+		 * the terminal device becomes idle.
+		 */
+
+		if (ch->ch_tun.un_open_count != 0 &&
+		    ((ch->ch_tun.un_tty->ops->chars_in_buffer)(ch->ch_tun.un_tty) != 0)) {
+			un->un_flag |= UN_PWAIT;
+			count = 0;
+			goto out;
+		}
+
+		/*
+		 * Assure that whenever there is printer data in the output
+		 * buffer, there always remains enough space after it to
+		 * turn the printer off.
+		 */
+		space -= ch->ch_digi.digi_offlen;
+
+		/*
+		 * Output the printer on string.
+		 */
+
+		if ((ch->ch_flag & CH_PRON) == 0) {
+			space -= ch->ch_digi.digi_onlen;
+
+			if (space < 0) {
+				un->un_flag |= UN_EMPTY;
+				(ch->ch_nd)->nd_tx_work = 1;
+				count = 0;
+				goto out;
+			}
+
+			drp_wmove(ch, 0, ch->ch_digi.digi_onstr,
+				ch->ch_digi.digi_onlen);
+
+			ch->ch_flag |= CH_PRON;
+		}
+
+		/*
+		 * We measure printer CPS speed by incrementing
+		 * ch_cpstime by (HZ / digi_maxcps) for every
+		 * character we output, restricting output so
+		 * that ch_cpstime never exceeds lbolt.
+		 *
+		 * However if output has not been done for some
+		 * time, lbolt will grow to very much larger than
+		 * ch_cpstime, which would allow essentially
+		 * unlimited amounts of output until ch_cpstime
+		 * finally caught up.   To avoid this, we adjust
+		 * cps_time when necessary so the difference
+		 * between lbolt and ch_cpstime never results
+		 * in sending more than digi_bufsize characters.
+		 *
+		 * This nicely models a printer with an internal
+		 * buffer of digi_bufsize characters.
+		 *
+		 * Get the time between lbolt and ch->ch_cpstime;
+		 */
+
+		tt = jiffies - ch->ch_cpstime;
+
+		/*
+		 * Compute the time required to send digi_bufsize
+		 * characters.
+		 */
+
+		mt = HZ * ch->ch_digi.digi_bufsize / ch->ch_digi.digi_maxcps;
+
+		/*
+		 * Compute the number of characters that can be sent
+		 * without violating the time constraint.   If the
+		 * direct calculation of this number is bigger than
+		 * digi_bufsize, limit the number to digi_bufsize,
+		 * and adjust cpstime to match.
+		 */
+
+		if ((clock_t)(tt + HZ) > (clock_t)(mt + HZ)) {
+			tmax = ch->ch_digi.digi_bufsize;
+			ch->ch_cpstime = jiffies - mt;
+		} else {
+			tmax = ch->ch_digi.digi_maxcps * tt / HZ;
+		}
+
+		/*
+		 * If the time constraint now binds, limit the transmit
+		 * count accordingly, and tentatively arrange to be
+		 * rescheduled based on time.
+		 */
+
+		if (tmax < space) {
+			space = tmax;
+			un_flag = UN_TIME;
+		}
+
+		/*
+		 * Compute the total number of characters we can
+		 * output before the total number of characters known
+		 * to be in the output queue exceeds digi_maxchar.
+		 */
+
+		tmax = (ch->ch_digi.digi_maxchar -
+			((ch->ch_tin - ch->ch_tout) & TBUF_MASK) -
+			((ch->ch_s_tin - ch->ch_s_tpos) & 0xffff));
+
+
+		/*
+		 * If the digi_maxchar constraint now holds, limit
+		 * the transmit count accordingly, and arrange to
+		 * be rescheduled when the queue becomes empty.
+		 */
+
+		if (space > tmax) {
+			space = tmax;
+			un_flag = UN_EMPTY;
+		}
+
+	}
+	/*
+	 * Handle the terminal device.
+	 */
+	else {
+
+		/*
+		 * If the printer device is on, turn it off.
+		 */
+
+		if ((ch->ch_flag & CH_PRON) != 0) {
+
+			space -= ch->ch_digi.digi_offlen;
+
+			drp_wmove(ch, 0, ch->ch_digi.digi_offstr,
+				  ch->ch_digi.digi_offlen);
+
+			ch->ch_flag &= ~CH_PRON;
+		}
+	}
+
+	/*
+	 *	If space is 0 and its because the ch->tbuf
+	 *	is full, then Linux will handle a callback when queue
+	 *	space becomes available.
+	 *	tty_write returns count = 0
+	 */
+
+	if (space <= 0) {
+		/* the linux tty_io.c handles this if we return 0 */
+		/* if (fp->flags & O_NONBLOCK) return -EAGAIN; */
+
+		un->un_flag |= UN_EMPTY;
+		(ch->ch_nd)->nd_tx_work = 1;
+		count = 0;
+		goto out;
+	}
+
+	count = min(count, space);
+
+	if (count > 0) {
+
+		un->un_tbusy++;
+
+		/*
+		 *	Copy the buffer contents to the ch_tbuf
+		 *	being careful to wrap around the circular queue
+		 */
+
+		t = TBUF_MAX - ch->ch_tin;
+		n = count;
+
+		if (n >= t) {
+			memcpy(ch->ch_tbuf + ch->ch_tin, buf, t);
+			if (nd->nd_dpa_debug && nd->nd_dpa_port == PORT_NUM(MINOR(tty_devnum(un->un_tty))))
+				dgrp_dpa_data(nd, 0, (char *) buf, t);
+			buf += t;
+			n -= t;
+			ch->ch_tin = 0;
+			sendcount += n;
+		}
+
+		memcpy(ch->ch_tbuf + ch->ch_tin, buf, n);
+		if (nd->nd_dpa_debug && nd->nd_dpa_port == PORT_NUM(MINOR(tty_devnum(un->un_tty))))
+			dgrp_dpa_data(nd, 0, (char *) buf, n);
+		buf += n;
+		ch->ch_tin += n;
+		sendcount += n;
+
+		un->un_tbusy--;
+		(ch->ch_nd)->nd_tx_work = 1;
+		if (ch->ch_edelay != DGRP_RTIME) {
+			(ch->ch_nd)->nd_tx_ready = 1;
+			wake_up_interruptible(&nd->nd_tx_waitq);
+		}
+	}
+
+	ch->ch_txcount += count;
+
+	if (IS_PRINT(MINOR(tty_devnum(tty)))) {
+
+		/*
+		 * Adjust ch_cpstime to account
+		 * for the characters just output.
+		 */
+
+		if (sendcount > 0) {
+			int cc = HZ * sendcount + ch->ch_cpsrem;
+
+			ch->ch_cpstime += cc / ch->ch_digi.digi_maxcps;
+			ch->ch_cpsrem   = cc % ch->ch_digi.digi_maxcps;
+		}
+
+		/*
+		 * If we are now waiting on time, schedule ourself
+		 * back when we'll be able to send a block of
+		 * digi_maxchar characters.
+		 */
+
+		if ((un_flag & UN_TIME) != 0) {
+			ch->ch_waketime = (ch->ch_cpstime +
+				(ch->ch_digi.digi_maxchar * HZ /
+				ch->ch_digi.digi_maxcps));
+		}
+	}
+
+	/*
+	 * If the printer unit is waiting for completion
+	 * of terminal output, get him going again.
+	 */
+
+	if ((ch->ch_pun.un_flag & UN_PWAIT) != 0)
+		(ch->ch_nd)->nd_tx_work = 1;
+
+out:
+	spin_unlock_irqrestore(&dgrp_poll_data.poll_lock, lock_flags);
+
+	return count;
+}
+
+
+/*
+ *	Put a character into ch->ch_buf
+ *
+ *	- used by the line discipline for OPOST processing
+ */
+
+static int dgrp_tty_put_char(struct tty_struct *tty, unsigned char new_char)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	ulong  lock_flags;
+	int space;
+	int retval = 0;
+
+	if (tty == NULL)
+		return 0;
+
+	un = tty->driver_data;
+	if (!un)
+		return 0;
+
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+
+	if (ch->ch_state != CS_READY)
+		return 0;
+
+	spin_lock_irqsave(&dgrp_poll_data.poll_lock, lock_flags);
+
+
+	/*
+	 *	If space is 0 and its because the ch->tbuf
+	 *	Warn and dump the character, there isn't anything else
+	 *	we can do about it.  David_Fries@digi.com
+	 */
+
+	space = (ch->ch_tout - ch->ch_tin - 1) & TBUF_MASK;
+
+	un->un_tbusy++;
+
+	/*
+	 * Output the printer on string if device is TXPrint.
+	 */
+	if (IS_PRINT(MINOR(tty_devnum(tty))) && (ch->ch_flag & CH_PRON) == 0) {
+		if (space < ch->ch_digi.digi_onlen) {
+			un->un_tbusy--;
+			goto out;
+		}
+		space -= ch->ch_digi.digi_onlen;
+		drp_wmove(ch, 0, ch->ch_digi.digi_onstr,
+			  ch->ch_digi.digi_onlen);
+		ch->ch_flag |= CH_PRON;
+	}
+
+	/*
+	 * Output the printer off string if device is NOT TXPrint.
+	 */
+
+	if (!IS_PRINT(MINOR(tty_devnum(tty))) &&
+	    ((ch->ch_flag & CH_PRON) != 0)) {
+		if (space < ch->ch_digi.digi_offlen) {
+			un->un_tbusy--;
+			goto out;
+		}
+
+		space -= ch->ch_digi.digi_offlen;
+		drp_wmove(ch, 0, ch->ch_digi.digi_offstr,
+			  ch->ch_digi.digi_offlen);
+		ch->ch_flag &= ~CH_PRON;
+	}
+
+	if (!space) {
+		un->un_tbusy--;
+		goto out;
+	}
+
+	/*
+	 *	Copy the character to the ch_tbuf being
+	 *	careful to wrap around the circular queue
+	 */
+	ch->ch_tbuf[ch->ch_tin] = new_char;
+	ch->ch_tin = (1 + ch->ch_tin) & TBUF_MASK;
+
+	if (IS_PRINT(MINOR(tty_devnum(tty)))) {
+
+		/*
+		 * Adjust ch_cpstime to account
+		 * for the character just output.
+		 */
+
+		int cc = HZ + ch->ch_cpsrem;
+
+		ch->ch_cpstime += cc / ch->ch_digi.digi_maxcps;
+		ch->ch_cpsrem   = cc % ch->ch_digi.digi_maxcps;
+
+		/*
+		 * If we are now waiting on time, schedule ourself
+		 * back when we'll be able to send a block of
+		 * digi_maxchar characters.
+		 */
+
+		ch->ch_waketime = (ch->ch_cpstime +
+			(ch->ch_digi.digi_maxchar * HZ /
+			ch->ch_digi.digi_maxcps));
+	}
+
+
+	un->un_tbusy--;
+	(ch->ch_nd)->nd_tx_work = 1;
+
+	retval = 1;
+out:
+	spin_unlock_irqrestore(&dgrp_poll_data.poll_lock, lock_flags);
+	return retval;
+}
+
+
+
+/*
+ *	Flush TX buffer (make in == out)
+ *
+ *	check tty_ioctl.c  -- this is called after TCOFLUSH
+ */
+static void dgrp_tty_flush_buffer(struct tty_struct *tty)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+	un = tty->driver_data;
+	if (!un)
+		return;
+
+	ch = un->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_tout = ch->ch_tin;
+	/* do NOT do this here! */
+	/* ch->ch_s_tpos = ch->ch_s_tin = 0; */
+
+	/* send the flush output command now */
+	ch->ch_send |= RR_TX_FLUSH;
+	(ch->ch_nd)->nd_tx_ready = 1;
+	(ch->ch_nd)->nd_tx_work = 1;
+	wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+
+	if (waitqueue_active(&tty->write_wait))
+		wake_up_interruptible(&tty->write_wait);
+
+	tty_wakeup(tty);
+
+}
+
+/*
+ *	Return space available in Tx buffer
+ *	count = ( ch->ch_tout - ch->ch_tin ) mod (TBUF_MAX - 1)
+ */
+static int dgrp_tty_write_room(struct tty_struct *tty)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int	count;
+
+	if (!tty)
+		return 0;
+
+	un = tty->driver_data;
+	if (!un)
+		return 0;
+
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+
+	count = (ch->ch_tout - ch->ch_tin - 1) & TBUF_MASK;
+
+	/* We *MUST* check this, and return 0 if the Printer Unit cannot
+	 * take any more data within its time constraints...  If we don't
+	 * return 0 and the printer has hit it time constraint, the ld will
+	 * call us back doing a put_char, which cannot be rejected!!!
+	 */
+	if (IS_PRINT(MINOR(tty_devnum(tty)))) {
+		int un_flag = 0;
+		count = dgrp_calculate_txprint_bounds(ch, count, &un_flag);
+		if (count <= 0)
+			count = 0;
+
+		ch->ch_pun.un_flag |= un_flag;
+		(ch->ch_nd)->nd_tx_work = 1;
+	}
+
+	return count;
+}
+
+/*
+ *	Return number of characters that have not been transmitted yet.
+ *	chars_in_buffer = ( ch->ch_tin - ch->ch_tout ) mod (TBUF_MAX - 1)
+ *			+ ( ch->ch_s_tin - ch->ch_s_tout ) mod (0xffff)
+ *			= number of characters "in transit"
+ *
+ * Remember that sequence number math is always with a sixteen bit
+ * mask, not the TBUF_MASK.
+ */
+
+static int dgrp_tty_chars_in_buffer(struct tty_struct *tty)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int	count;
+	int	count1;
+
+	if (!tty)
+		return 0;
+
+	un = tty->driver_data;
+	if (!un)
+		return 0;
+
+	ch = un->un_ch;
+	if (!ch)
+		return 0;
+
+	count1 = count = (ch->ch_tin - ch->ch_tout) & TBUF_MASK;
+	count += (ch->ch_s_tin - ch->ch_s_tpos) & 0xffff;
+	/* one for tbuf, one for the PS */
+
+	/*
+	 * If we are busy transmitting add 1
+	 */
+	count += un->un_tbusy;
+
+	return count;
+}
+
+
+/*****************************************************************************
+ *
+ * Helper applications for dgrp_tty_ioctl()
+ *
+ *****************************************************************************
+ */
+
+
+/**
+ * ch_to_tty_flags() -- convert channel flags to termio flags
+ * @ch_flag: Digi channel flags
+ * @flagtype: type of ch_flag (iflag, oflag or cflag)
+ *
+ * take the channel flags of the specified type and return the
+ * corresponding termio flag
+ */
+static tcflag_t ch_to_tty_flags(ushort ch_flag, char flagtype)
+{
+	tcflag_t retval = 0;
+
+	switch (flagtype) {
+	case 'i':
+		retval = ((ch_flag & IF_IGNBRK) ? IGNBRK : 0)
+		     | ((ch_flag & IF_BRKINT) ? BRKINT : 0)
+		     | ((ch_flag & IF_IGNPAR) ? IGNPAR : 0)
+		     | ((ch_flag & IF_PARMRK) ? PARMRK : 0)
+		     | ((ch_flag & IF_INPCK) ? INPCK  : 0)
+		     | ((ch_flag & IF_ISTRIP) ? ISTRIP : 0)
+		     | ((ch_flag & IF_IXON) ? IXON   : 0)
+		     | ((ch_flag & IF_IXANY) ? IXANY  : 0)
+		     | ((ch_flag & IF_IXOFF) ? IXOFF  : 0);
+		break;
+
+	case 'o':
+		retval = ((ch_flag & OF_OLCUC) ? OLCUC : 0)
+		     | ((ch_flag & OF_ONLCR) ? ONLCR  : 0)
+		     | ((ch_flag & OF_OCRNL) ? OCRNL  : 0)
+		     | ((ch_flag & OF_ONOCR) ? ONOCR  : 0)
+		     | ((ch_flag & OF_ONLRET) ? ONLRET : 0)
+		  /* | ((ch_flag & OF_OTAB3) ? OFILL  : 0) */
+		     | ((ch_flag & OF_TABDLY) ? TABDLY : 0);
+		break;
+
+	case 'c':
+		retval = ((ch_flag & CF_CSTOPB) ? CSTOPB : 0)
+		     | ((ch_flag & CF_CREAD) ? CREAD  : 0)
+		     | ((ch_flag & CF_PARENB) ? PARENB : 0)
+		     | ((ch_flag & CF_PARODD) ? PARODD : 0)
+		     | ((ch_flag & CF_HUPCL) ? HUPCL  : 0);
+
+		switch (ch_flag & CF_CSIZE) {
+		case CF_CS5:
+			retval |= CS5;
+			break;
+		case CF_CS6:
+			retval |= CS6;
+			break;
+		case CF_CS7:
+			retval |= CS7;
+			break;
+		case CF_CS8:
+			retval |= CS8;
+			break;
+		default:
+			retval |= CS8;
+			break;
+		}
+		break;
+	case 'x':
+		break;
+	case 'l':
+		break;
+	default:
+		return 0;
+	}
+
+	return retval;
+}
+
+
+/**
+ * tty_to_ch_flags() -- convert termio flags to digi channel flags
+ * @tty: pointer to a TTY structure holding flag to be converted
+ * @flagtype: identifies which flag (iflags, oflags, or cflags) should
+ *                 be converted
+ *
+ * take the termio flag of the specified type and return the
+ * corresponding Digi version of the flags
+ */
+static ushort tty_to_ch_flags(struct tty_struct *tty, char flagtype)
+{
+	ushort retval = 0;
+	tcflag_t tflag = 0;
+
+	switch (flagtype) {
+	case 'i':
+		tflag  = tty->termios.c_iflag;
+		retval = (I_IGNBRK(tty) ? IF_IGNBRK : 0)
+		      | (I_BRKINT(tty) ? IF_BRKINT : 0)
+		      | (I_IGNPAR(tty) ? IF_IGNPAR : 0)
+		      | (I_PARMRK(tty) ? IF_PARMRK : 0)
+		      | (I_INPCK(tty)  ? IF_INPCK  : 0)
+		      | (I_ISTRIP(tty) ? IF_ISTRIP : 0)
+		      | (I_IXON(tty)   ? IF_IXON   : 0)
+		      | (I_IXANY(tty)  ? IF_IXANY  : 0)
+		      | (I_IXOFF(tty)  ? IF_IXOFF  : 0);
+		break;
+	case 'o':
+		tflag  = tty->termios.c_oflag;
+		/*
+		 * If OPOST is set, then do the post processing in the
+		 * firmware by setting all the processing flags on.
+		 * If ~OPOST, then make sure we are not doing any
+		 * output processing!!
+		 */
+		if (!O_OPOST(tty))
+			retval = 0;
+		else
+			retval = (O_OLCUC(tty) ? OF_OLCUC : 0)
+			     | (O_ONLCR(tty)  ? OF_ONLCR  : 0)
+			     | (O_OCRNL(tty)  ? OF_OCRNL  : 0)
+			     | (O_ONOCR(tty)  ? OF_ONOCR  : 0)
+			     | (O_ONLRET(tty) ? OF_ONLRET : 0)
+			  /* | (O_OFILL(tty)  ? OF_TAB3   : 0) */
+			     | (O_TABDLY(tty) ? OF_TABDLY : 0);
+		break;
+	case 'c':
+		tflag  = tty->termios.c_cflag;
+		retval = (C_CSTOPB(tty) ? CF_CSTOPB : 0)
+		     | (C_CREAD(tty)  ? CF_CREAD  : 0)
+		     | (C_PARENB(tty) ? CF_PARENB : 0)
+		     | (C_PARODD(tty) ? CF_PARODD : 0)
+		     | (C_HUPCL(tty)  ? CF_HUPCL  : 0);
+		switch (C_CSIZE(tty)) {
+		case CS8:
+			retval |= CF_CS8;
+			break;
+		case CS7:
+			retval |= CF_CS7;
+			break;
+		case CS6:
+			retval |= CF_CS6;
+			break;
+		case CS5:
+			retval |= CF_CS5;
+			break;
+		default:
+			retval |= CF_CS8;
+			break;
+		}
+		break;
+	case 'x':
+		break;
+	case 'l':
+		break;
+	default:
+		return 0;
+	}
+
+	return retval;
+}
+
+
+static int dgrp_tty_send_break(struct tty_struct *tty, int msec)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int ret = -EIO;
+
+	if (!tty)
+		return ret;
+
+	un = tty->driver_data;
+	if (!un)
+		return ret;
+
+	ch = un->un_ch;
+	if (!ch)
+		return ret;
+
+	dgrp_send_break(ch, msec);
+	return 0;
+}
+
+
+/*
+ * This routine sends a break character out the serial port.
+ *
+ * duration is in 1/1000's of a second
+ */
+static int dgrp_send_break(struct ch_struct *ch, int msec)
+{
+	ulong x;
+
+	wait_event_interruptible(ch->ch_flag_wait,
+		((ch->ch_flag & CH_TX_BREAK) == 0));
+	ch->ch_break_time += max(msec, 250);
+	ch->ch_send |= RR_TX_BREAK;
+	ch->ch_flag |= CH_TX_BREAK;
+	(ch->ch_nd)->nd_tx_work = 1;
+
+	x = (msec * HZ) / 1000;
+	wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+
+	return 0;
+}
+
+
+/*
+ * Return modem signals to ld.
+ */
+static int dgrp_tty_tiocmget(struct tty_struct *tty)
+{
+	unsigned int mlast;
+	struct un_struct *un = tty->driver_data;
+	struct ch_struct *ch;
+
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	mlast = ((ch->ch_s_mlast & ~(DM_RTS | DM_DTR)) |
+		(ch->ch_mout & (DM_RTS | DM_DTR)));
+
+	/* defined in /usr/include/asm/termios.h */
+	mlast =   ((mlast & DM_RTS) ? TIOCM_RTS : 0)
+		| ((mlast & DM_DTR) ? TIOCM_DTR : 0)
+		| ((mlast & DM_CD)  ? TIOCM_CAR : 0)
+		| ((mlast & DM_RI)  ? TIOCM_RNG : 0)
+		| ((mlast & DM_DSR) ? TIOCM_DSR : 0)
+		| ((mlast & DM_CTS) ? TIOCM_CTS : 0);
+
+	return mlast;
+}
+
+
+/*
+ *      Set modem lines
+ */
+static int dgrp_tty_tiocmset(struct tty_struct *tty,
+			     unsigned int set, unsigned int clear)
+{
+	ulong lock_flags;
+	struct un_struct *un = tty->driver_data;
+	struct ch_struct *ch;
+
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	if (set & TIOCM_RTS)
+		ch->ch_mout |= DM_RTS;
+
+	if (set & TIOCM_DTR)
+		ch->ch_mout |= DM_DTR;
+
+	if (clear & TIOCM_RTS)
+		ch->ch_mout &= ~(DM_RTS);
+
+	if (clear & TIOCM_DTR)
+		ch->ch_mout &= ~(DM_DTR);
+
+	spin_lock_irqsave(&(ch->ch_nd)->nd_lock, lock_flags);
+	ch->ch_flag |= CH_PARAM;
+	(ch->ch_nd)->nd_tx_work = 1;
+	wake_up_interruptible(&ch->ch_flag_wait);
+
+	spin_unlock_irqrestore(&(ch->ch_nd)->nd_lock, lock_flags);
+
+	return 0;
+}
+
+
+
+/*
+ *      Get current modem status
+ */
+static int get_modem_info(struct ch_struct *ch, unsigned int *value)
+{
+	unsigned int mlast;
+
+	mlast = ((ch->ch_s_mlast & ~(DM_RTS | DM_DTR)) |
+		(ch->ch_mout    &  (DM_RTS | DM_DTR)));
+
+	/* defined in /usr/include/asm/termios.h */
+	mlast =   ((mlast & DM_RTS) ? TIOCM_RTS : 0)
+		| ((mlast & DM_DTR) ? TIOCM_DTR : 0)
+		| ((mlast & DM_CD)  ? TIOCM_CAR : 0)
+		| ((mlast & DM_RI)  ? TIOCM_RNG : 0)
+		| ((mlast & DM_DSR) ? TIOCM_DSR : 0)
+		| ((mlast & DM_CTS) ? TIOCM_CTS : 0);
+	put_user(mlast, (unsigned int __user *) value);
+
+	return 0;
+}
+
+/*
+ *      Set modem lines
+ */
+static int set_modem_info(struct ch_struct *ch, unsigned int command,
+			  unsigned int *value)
+{
+	int error;
+	unsigned int arg;
+	int mval = 0;
+	ulong lock_flags;
+
+	error = access_ok(VERIFY_READ, (void __user *) value, sizeof(int));
+	if (error == 0)
+		return -EFAULT;
+
+	get_user(arg, (unsigned int __user *) value);
+	mval |= ((arg & TIOCM_RTS) ? DM_RTS : 0)
+		| ((arg & TIOCM_DTR) ? DM_DTR : 0);
+
+	switch (command) {
+	case TIOCMBIS:  /* set flags */
+		ch->ch_mout |= mval;
+		break;
+	case TIOCMBIC:  /* clear flags */
+		ch->ch_mout &= ~mval;
+		break;
+	case TIOCMSET:
+		ch->ch_mout = mval;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	spin_lock_irqsave(&(ch->ch_nd)->nd_lock, lock_flags);
+
+	ch->ch_flag |= CH_PARAM;
+	(ch->ch_nd)->nd_tx_work = 1;
+	wake_up_interruptible(&ch->ch_flag_wait);
+
+	spin_unlock_irqrestore(&(ch->ch_nd)->nd_lock, lock_flags);
+
+	return 0;
+}
+
+
+/*
+ *  Assign the custom baud rate to the channel structure
+ */
+static void dgrp_set_custom_speed(struct ch_struct *ch, int newrate)
+{
+	int testdiv;
+	int testrate_high;
+	int testrate_low;
+
+	int deltahigh, deltalow;
+
+	if (newrate < 0)
+		newrate = 0;
+
+	/*
+	 * Since the divisor is stored in a 16-bit integer, we make sure
+	 * we don't allow any rates smaller than a 16-bit integer would allow.
+	 * And of course, rates above the dividend won't fly.
+	 */
+	if (newrate && newrate < ((PORTSERVER_DIVIDEND / 0xFFFF) + 1))
+		newrate = ((PORTSERVER_DIVIDEND / 0xFFFF) + 1);
+	if (newrate && newrate > PORTSERVER_DIVIDEND)
+		newrate = PORTSERVER_DIVIDEND;
+
+	while (newrate > 0) {
+		testdiv = PORTSERVER_DIVIDEND / newrate;
+
+		/*
+		 * If we try to figure out what rate the PortServer would use
+		 * with the test divisor, it will be either equal or higher
+		 * than the requested baud rate.  If we then determine the
+		 * rate with a divisor one higher, we will get the next lower
+		 * supported rate below the requested.
+		 */
+		testrate_high = PORTSERVER_DIVIDEND / testdiv;
+		testrate_low  = PORTSERVER_DIVIDEND / (testdiv + 1);
+
+		/*
+		 * If the rate for the requested divisor is correct, just
+		 * use it and be done.
+		 */
+		if (testrate_high == newrate)
+			break;
+
+		/*
+		 * Otherwise, pick the rate that is closer (i.e. whichever rate
+		 * has a smaller delta).
+		 */
+		deltahigh = testrate_high - newrate;
+		deltalow = newrate - testrate_low;
+
+		if (deltahigh < deltalow)
+			newrate = testrate_high;
+		else
+			newrate = testrate_low;
+
+		break;
+	}
+
+	ch->ch_custom_speed = newrate;
+
+	drp_param(ch);
+
+	return;
+}
+
+
+/*
+ # dgrp_tty_digiseta()
+ *
+ * Ioctl to set the information from ditty.
+ *
+ * NOTE: DIGI_IXON, DSRPACE, DCDPACE, and DTRPACE are unsupported.  JAR 990922
+ */
+static int dgrp_tty_digiseta(struct tty_struct *tty,
+			     struct digi_struct *new_info)
+{
+	struct un_struct *un = tty->driver_data;
+	struct ch_struct *ch;
+
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	if (copy_from_user(&ch->ch_digi, (void __user *) new_info,
+			   sizeof(struct digi_struct)))
+		return -EFAULT;
+
+	if ((ch->ch_digi.digi_flags & RTSPACE) ||
+	    (ch->ch_digi.digi_flags & CTSPACE))
+		tty->termios.c_cflag |= CRTSCTS;
+	else
+		tty->termios.c_cflag &= ~CRTSCTS;
+
+	if (ch->ch_digi.digi_maxcps < 1)
+		ch->ch_digi.digi_maxcps = 1;
+
+	if (ch->ch_digi.digi_maxcps > 10000)
+		ch->ch_digi.digi_maxcps = 10000;
+
+	if (ch->ch_digi.digi_bufsize < 10)
+		ch->ch_digi.digi_bufsize = 10;
+
+	if (ch->ch_digi.digi_maxchar < 1)
+		ch->ch_digi.digi_maxchar = 1;
+
+	if (ch->ch_digi.digi_maxchar > ch->ch_digi.digi_bufsize)
+		ch->ch_digi.digi_maxchar = ch->ch_digi.digi_bufsize;
+
+	if (ch->ch_digi.digi_onlen > DIGI_PLEN)
+		ch->ch_digi.digi_onlen = DIGI_PLEN;
+
+	if (ch->ch_digi.digi_offlen > DIGI_PLEN)
+		ch->ch_digi.digi_offlen = DIGI_PLEN;
+
+	/* make the changes now */
+	drp_param(ch);
+
+	return 0;
+}
+
+
+
+/*
+ * dgrp_tty_digigetedelay()
+ *
+ * Ioctl to get the current edelay setting.
+ *
+ *
+ *
+ */
+static int dgrp_tty_digigetedelay(struct tty_struct *tty, int *retinfo)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int tmp;
+
+	if (!retinfo)
+		return -EFAULT;
+
+	if (!tty || tty->magic != TTY_MAGIC)
+		return -EFAULT;
+
+	un = tty->driver_data;
+
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	tmp = ch->ch_edelay;
+
+	if (copy_to_user((void __user *) retinfo, &tmp, sizeof(*retinfo)))
+		return -EFAULT;
+
+	return 0;
+}
+
+
+/*
+ * dgrp_tty_digisetedelay()
+ *
+ * Ioctl to set the EDELAY setting
+ *
+ */
+static int dgrp_tty_digisetedelay(struct tty_struct *tty, int *new_info)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int new_digi;
+
+	if (!tty || tty->magic != TTY_MAGIC)
+		return -EFAULT;
+
+	un = tty->driver_data;
+
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	if (copy_from_user(&new_digi, (void __user *)new_info, sizeof(int)))
+		return -EFAULT;
+
+	ch->ch_edelay = new_digi;
+
+	/* make the changes now */
+	drp_param(ch);
+
+	return 0;
+}
+
+
+/*
+ *	The usual assortment of ioctl's
+ *
+ *	note:  use tty_check_change to make sure that we are not
+ *	changing the state of a terminal when we are not a process
+ *	in the forground.  See tty_io.c
+ *		rc = tty_check_change(tty);
+ *		if (rc) return rc;
+ */
+static int dgrp_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
+			  unsigned long arg)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+	int rc;
+	struct digiflow_struct   dflow;
+
+	if (!tty)
+		return -ENODEV;
+
+	un = tty->driver_data;
+	if (!un)
+		return -ENODEV;
+
+	ch = un->un_ch;
+	if (!ch)
+		return -ENODEV;
+
+	switch (cmd) {
+
+	/*
+	 * Here are all the standard ioctl's that we MUST implement
+	 */
+
+	case TCSBRK:
+		/*
+		 * TCSBRK is SVID version: non-zero arg --> no break
+		 * this behaviour is exploited by tcdrain().
+		 *
+		 * According to POSIX.1 spec (7.2.2.1.2) breaks should be
+		 * between 0.25 and 0.5 seconds
+		 */
+
+		rc = tty_check_change(tty);
+		if (rc)
+			return rc;
+		tty_wait_until_sent(tty, 0);
+
+		if (!arg)
+			rc = dgrp_send_break(ch, 250); /* 1/4 second */
+
+		if (dgrp_tty_chars_in_buffer(tty) != 0)
+			return -EINTR;
+
+		return 0;
+
+	case TCSBRKP:
+		/* support for POSIX tcsendbreak()
+		 *
+		 * According to POSIX.1 spec (7.2.2.1.2) breaks should be
+		 * between 0.25 and 0.5 seconds so we'll ask for something
+		 * in the middle: 0.375 seconds.
+		 */
+		rc = tty_check_change(tty);
+		if (rc)
+			return rc;
+		tty_wait_until_sent(tty, 0);
+
+		rc = dgrp_send_break(ch, arg ? arg*250 : 250);
+
+		if (dgrp_tty_chars_in_buffer(tty) != 0)
+			return -EINTR;
+		return 0;
+
+	case TIOCSBRK:
+		rc = tty_check_change(tty);
+		if (rc)
+			return rc;
+		tty_wait_until_sent(tty, 0);
+
+		/*
+		 * RealPort doesn't support turning on a break unconditionally.
+		 * The RealPort device will stop sending a break automatically
+		 * after the specified time value that we send in.
+		 */
+		rc = dgrp_send_break(ch, 250); /* 1/4 second */
+
+		if (dgrp_tty_chars_in_buffer(tty) != 0)
+			return -EINTR;
+		return 0;
+
+	case TIOCCBRK:
+		/*
+		 * RealPort doesn't support turning off a break unconditionally.
+		 * The RealPort device will stop sending a break automatically
+		 * after the specified time value that was sent when turning on
+		 * the break.
+		 */
+		return 0;
+
+	case TIOCGSOFTCAR:
+		rc = access_ok(VERIFY_WRITE, (void __user *) arg,
+			       sizeof(long));
+		if (rc == 0)
+			return -EFAULT;
+		put_user(C_CLOCAL(tty) ? 1 : 0, (unsigned long __user *) arg);
+		return 0;
+
+	case TIOCSSOFTCAR:
+		get_user(arg, (unsigned long __user *) arg);
+		tty->termios.c_cflag =
+			((tty->termios.c_cflag & ~CLOCAL) |
+			 (arg ? CLOCAL : 0));
+		return 0;
+
+	case TIOCMGET:
+		rc = access_ok(VERIFY_WRITE, (void __user *) arg,
+				 sizeof(unsigned int));
+		if (rc == 0)
+			return -EFAULT;
+		return get_modem_info(ch, (unsigned int *) arg);
+
+	case TIOCMBIS:
+	case TIOCMBIC:
+	case TIOCMSET:
+		return set_modem_info(ch, cmd, (unsigned int *) arg);
+
+	/*
+	 * Here are any additional ioctl's that we want to implement
+	 */
+
+	case TCFLSH:
+		/*
+		 * The linux tty driver doesn't have a flush
+		 * input routine for the driver, assuming all backed
+		 * up data is in the line disc. buffers.  However,
+		 * we all know that's not the case.  Here, we
+		 * act on the ioctl, but then lie and say we didn't
+		 * so the line discipline will process the flush
+		 * also.
+		 */
+		rc = tty_check_change(tty);
+		if (rc)
+			return rc;
+
+		switch (arg) {
+		case TCIFLUSH:
+		case TCIOFLUSH:
+			/* only flush input if this is the only open unit */
+			if (!IS_PRINT(MINOR(tty_devnum(tty)))) {
+				ch->ch_rout = ch->ch_rin;
+				ch->ch_send |= RR_RX_FLUSH;
+				(ch->ch_nd)->nd_tx_work = 1;
+				(ch->ch_nd)->nd_tx_ready = 1;
+				wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+			}
+			if (arg == TCIFLUSH)
+				break;
+
+		case TCOFLUSH: /* flush output, or the receive buffer */
+			/*
+			 * This is handled in the tty_ioctl.c code
+			 * calling tty_flush_buffer
+			 */
+			break;
+
+		default:
+			/* POSIX.1 says return EINVAL if we got a bad arg */
+			return -EINVAL;
+		}
+		/* pretend we didn't recognize this IOCTL */
+		return -ENOIOCTLCMD;
+
+#ifdef TIOCGETP
+	case TIOCGETP:
+#endif
+	/*****************************************
+	Linux		HPUX		Function
+	TCSETA		TCSETA		- set the termios
+	TCSETAF		TCSETAF		- wait for drain first, then set termios
+	TCSETAW		TCSETAW		- wait for drain, flush the input queue, then set termios
+	- looking at the tty_ioctl code, these command all call our
+	tty_set_termios at the driver's end, when a TCSETA* is sent,
+	it is expecting the tty to have a termio structure,
+	NOT a termios stucture.  These two structures differ in size
+	and the tty_ioctl code does a conversion before processing them both.
+	- we should treat the TCSETAW TCSETAF ioctls the same, and let
+	the tty_ioctl code do the conversion stuff.
+
+	TCSETS
+	TCSETSF		(none)
+	TCSETSW
+	- the associated tty structure has a termios structure.
+	*****************************************/
+
+	case TCGETS:
+	case TCGETA:
+		return -ENOIOCTLCMD;
+
+	case TCSETAW:
+	case TCSETAF:
+	case TCSETSF:
+	case TCSETSW:
+		/*
+		 * The linux tty driver doesn't have a flush
+		 * input routine for the driver, assuming all backed
+		 * up data is in the line disc. buffers.  However,
+		 * we all know that's not the case.  Here, we
+		 * act on the ioctl, but then lie and say we didn't
+		 * so the line discipline will process the flush
+		 * also.
+		 */
+
+		/*
+		 * Also, now that we have TXPrint, we have to check
+		 * if this is the TXPrint device and the terminal
+		 * device is open. If so, do NOT run check_change,
+		 * as the terminal device is ALWAYS the parent.
+		 */
+		if (!IS_PRINT(MINOR(tty_devnum(tty))) ||
+		    !ch->ch_tun.un_open_count) {
+			rc = tty_check_change(tty);
+			if (rc)
+				return rc;
+		}
+
+		/* wait for all the characters in tbuf to drain */
+		tty_wait_until_sent(tty, 0);
+
+		if ((cmd == TCSETSF) || (cmd == TCSETAF)) {
+			/* flush the contents of the rbuf queue */
+			/* TODO:  check if this is print device? */
+			ch->ch_send |= RR_RX_FLUSH;
+			(ch->ch_nd)->nd_tx_ready = 1;
+			(ch->ch_nd)->nd_tx_work = 1;
+			wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+			/* do we need to do this?  just to be safe! */
+			ch->ch_rout = ch->ch_rin;
+		}
+
+		/* pretend we didn't recognize this */
+		return -ENOIOCTLCMD;
+
+	case TCXONC:
+		/*
+		 * The Linux Line Discipline (LD) would do this for us if we
+		 * let it, but we have the special firmware options to do this
+		 * the "right way" regardless of hardware or software flow
+		 * control so we'll do it outselves instead of letting the LD
+		 * do it.
+		 */
+		rc = tty_check_change(tty);
+		if (rc)
+			return rc;
+
+		switch (arg) {
+		case TCOON:
+			dgrp_tty_start(tty);
+			return 0;
+		case TCOOFF:
+			dgrp_tty_stop(tty);
+			return 0;
+		case TCION:
+			dgrp_tty_input_start(tty);
+			return 0;
+		case TCIOFF:
+			dgrp_tty_input_stop(tty);
+			return 0;
+		default:
+			return -EINVAL;
+		}
+
+	case DIGI_GETA:
+		/* get information for ditty */
+		if (copy_to_user((struct digi_struct __user *) arg,
+				 &ch->ch_digi, sizeof(struct digi_struct)))
+			return -EFAULT;
+		break;
+
+	case DIGI_SETAW:
+	case DIGI_SETAF:
+		/* wait for all the characters in tbuf to drain */
+		tty_wait_until_sent(tty, 0);
+
+		if (cmd == DIGI_SETAF) {
+			/* flush the contents of the rbuf queue */
+			/* send down a packet with RR_RX_FLUSH set */
+			ch->ch_send |= RR_RX_FLUSH;
+			(ch->ch_nd)->nd_tx_ready = 1;
+			(ch->ch_nd)->nd_tx_work = 1;
+			wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+			/* do we need to do this?  just to be safe! */
+			ch->ch_rout = ch->ch_rin;
+		}
+
+		/* pretend we didn't recognize this */
+
+	case DIGI_SETA:
+		return dgrp_tty_digiseta(tty, (struct digi_struct *) arg);
+
+	case DIGI_SEDELAY:
+		return dgrp_tty_digisetedelay(tty, (int *) arg);
+
+	case DIGI_GEDELAY:
+		return dgrp_tty_digigetedelay(tty, (int *) arg);
+
+	case DIGI_GETFLOW:
+	case DIGI_GETAFLOW:
+		if (cmd == (DIGI_GETFLOW)) {
+			dflow.startc = tty->termios.c_cc[VSTART];
+			dflow.stopc = tty->termios.c_cc[VSTOP];
+		} else {
+			dflow.startc = ch->ch_xxon;
+			dflow.stopc = ch->ch_xxoff;
+		}
+
+		if (copy_to_user((char __user *)arg, &dflow, sizeof(dflow)))
+			return -EFAULT;
+		break;
+
+	case DIGI_SETFLOW:
+	case DIGI_SETAFLOW:
+
+		if (copy_from_user(&dflow, (char __user *)arg, sizeof(dflow)))
+			return -EFAULT;
+
+		if (cmd == (DIGI_SETFLOW)) {
+			tty->termios.c_cc[VSTART] = dflow.startc;
+			tty->termios.c_cc[VSTOP] = dflow.stopc;
+		} else {
+			ch->ch_xxon = dflow.startc;
+			ch->ch_xxoff = dflow.stopc;
+		}
+		break;
+
+	case DIGI_GETCUSTOMBAUD:
+		rc = access_ok(VERIFY_WRITE, (void __user *) arg, sizeof(int));
+		if (rc == 0)
+			return -EFAULT;
+		put_user(ch->ch_custom_speed, (unsigned int __user *) arg);
+		break;
+
+	case DIGI_SETCUSTOMBAUD:
+	{
+		int new_rate;
+
+		get_user(new_rate, (unsigned int __user *) arg);
+		dgrp_set_custom_speed(ch, new_rate);
+
+		break;
+	}
+
+	default:
+		return -ENOIOCTLCMD;
+	}
+
+	return 0;
+}
+
+/*
+ *  This routine allows the tty driver to be notified when
+ *  the device's termios setting have changed.  Note that we
+ *  should be prepared to accept the case where old == NULL
+ *  and try to do something rational.
+ *
+ *  So we need to make sure that our copies of ch_oflag,
+ *  ch_clag, and ch_iflag reflect the tty->termios flags.
+ */
+static void dgrp_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
+{
+	struct ktermios *ts;
+	struct ch_struct *ch;
+	struct un_struct *un;
+
+	/* seems silly, but we have to check all these! */
+	if (!tty)
+		return;
+
+	un = tty->driver_data;
+	if (!un)
+		return;
+
+	ts = &tty->termios;
+
+	ch = un->un_ch;
+	if (!ch)
+		return;
+
+	drp_param(ch);
+
+	/* the CLOCAL flag has just been set */
+	if (!(old->c_cflag & CLOCAL) && C_CLOCAL(tty))
+		wake_up_interruptible(&un->un_open_wait);
+}
+
+
+/*
+ *	Throttle receiving data.  We just set a bit and stop reading
+ *	data out of the channel buffer.  It will back up and the
+ *	FEP will do whatever is necessary to stop the far end.
+ */
+static void dgrp_tty_throttle(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_flag |= CH_RXSTOP;
+}
+
+
+static void dgrp_tty_unthrottle(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_flag &= ~CH_RXSTOP;
+}
+
+/*
+ *	Stop the transmitter
+ */
+static void dgrp_tty_stop(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_send |= RR_TX_STOP;
+	ch->ch_send &= ~RR_TX_START;
+
+	/* make the change NOW! */
+	(ch->ch_nd)->nd_tx_ready = 1;
+	if (waitqueue_active(&(ch->ch_nd)->nd_tx_waitq))
+		wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+}
+
+/*
+ *	Start the transmitter
+ */
+static void dgrp_tty_start(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	/* TODO: don't do anything if the transmitter is not stopped */
+
+	ch->ch_send |= RR_TX_START;
+	ch->ch_send &= ~RR_TX_STOP;
+
+	/* make the change NOW! */
+	(ch->ch_nd)->nd_tx_ready = 1;
+	(ch->ch_nd)->nd_tx_work = 1;
+	if (waitqueue_active(&(ch->ch_nd)->nd_tx_waitq))
+		wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+
+}
+
+/*
+ *	Stop the reciever
+ */
+static void dgrp_tty_input_stop(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_send |= RR_RX_STOP;
+	ch->ch_send &= ~RR_RX_START;
+	(ch->ch_nd)->nd_tx_ready = 1;
+	if (waitqueue_active(&(ch->ch_nd)->nd_tx_waitq))
+		wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+
+}
+
+
+static void dgrp_tty_send_xchar(struct tty_struct *tty, char c)
+{
+	struct un_struct *un;
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	un = tty->driver_data;
+	if (!un)
+		return;
+
+	ch = un->un_ch;
+	if (!ch)
+		return;
+	if (c == STOP_CHAR(tty))
+		ch->ch_send |= RR_RX_STOP;
+	else if (c == START_CHAR(tty))
+		ch->ch_send |= RR_RX_START;
+
+	ch->ch_nd->nd_tx_ready = 1;
+	ch->ch_nd->nd_tx_work = 1;
+
+	return;
+}
+
+
+static void dgrp_tty_input_start(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+
+	if (!tty)
+		return;
+
+	ch = ((struct un_struct *) tty->driver_data)->un_ch;
+	if (!ch)
+		return;
+
+	ch->ch_send |= RR_RX_START;
+	ch->ch_send &= ~RR_RX_STOP;
+	(ch->ch_nd)->nd_tx_ready = 1;
+	(ch->ch_nd)->nd_tx_work = 1;
+	if (waitqueue_active(&(ch->ch_nd)->nd_tx_waitq))
+		wake_up_interruptible(&(ch->ch_nd)->nd_tx_waitq);
+
+}
+
+
+/*
+ *	Hangup the port.  Like a close, but don't wait for output
+ *	to drain.
+ *
+ *	How do we close all the channels that are open?
+ */
+static void dgrp_tty_hangup(struct tty_struct *tty)
+{
+	struct ch_struct *ch;
+	struct nd_struct *nd;
+	struct un_struct *un;
+
+	if (!tty)
+		return;
+
+	un = tty->driver_data;
+	if (!un)
+		return;
+
+	ch = un->un_ch;
+	if (!ch)
+		return;
+
+	nd = ch->ch_nd;
+
+	if (C_HUPCL(tty)) {
+		/* LOWER DTR */
+		ch->ch_mout &= ~DM_DTR;
+		/* Don't do this here */
+		/* ch->ch_flag |= CH_HANGUP; */
+		ch->ch_nd->nd_tx_ready = 1;
+		ch->ch_nd->nd_tx_work  = 1;
+		if (waitqueue_active(&ch->ch_flag_wait))
+			wake_up_interruptible(&ch->ch_flag_wait);
+	}
+
+}
+
+/************************************************************************/
+/*                                                                      */
+/*       TTY Initialization/Cleanup Functions                           */
+/*                                                                      */
+/************************************************************************/
+
+/*
+ *	Uninitialize the TTY portion of the supplied node.  Free all
+ *      memory and resources associated with this node.  Do it in reverse
+ *      allocation order: this might possibly result in less fragmentation
+ *      of memory, though I don't know this for sure.
+ */
+void
+dgrp_tty_uninit(struct nd_struct *nd)
+{
+	char id[3];
+
+	ID_TO_CHAR(nd->nd_ID, id);
+
+	if (nd->nd_ttdriver_flags & SERIAL_TTDRV_REG) {
+		tty_unregister_driver(nd->nd_serial_ttdriver);
+
+		kfree(nd->nd_serial_ttdriver->ttys);
+		nd->nd_serial_ttdriver->ttys = NULL;
+
+		put_tty_driver(nd->nd_serial_ttdriver);
+		nd->nd_ttdriver_flags &= ~SERIAL_TTDRV_REG;
+	}
+
+	if (nd->nd_ttdriver_flags & CALLOUT_TTDRV_REG) {
+		tty_unregister_driver(nd->nd_callout_ttdriver);
+
+		kfree(nd->nd_callout_ttdriver->ttys);
+		nd->nd_callout_ttdriver->ttys = NULL;
+
+		put_tty_driver(nd->nd_callout_ttdriver);
+		nd->nd_ttdriver_flags &= ~CALLOUT_TTDRV_REG;
+	}
+
+	if (nd->nd_ttdriver_flags & XPRINT_TTDRV_REG) {
+		tty_unregister_driver(nd->nd_xprint_ttdriver);
+
+		kfree(nd->nd_xprint_ttdriver->ttys);
+		nd->nd_xprint_ttdriver->ttys = NULL;
+
+		put_tty_driver(nd->nd_xprint_ttdriver);
+		nd->nd_ttdriver_flags &= ~XPRINT_TTDRV_REG;
+	}
+}
+
+
+
+/*
+ *     Initialize the TTY portion of the supplied node.
+ */
+int
+dgrp_tty_init(struct nd_struct *nd)
+{
+	char id[3];
+	int  rc;
+	int  i;
+
+	ID_TO_CHAR(nd->nd_ID, id);
+
+	/*
+	 *  Initialize the TTDRIVER structures.
+	 */
+
+	nd->nd_serial_ttdriver = alloc_tty_driver(CHAN_MAX);
+	sprintf(nd->nd_serial_name,  "tty_dgrp_%s_", id);
+
+	nd->nd_serial_ttdriver->owner = THIS_MODULE;
+	nd->nd_serial_ttdriver->name = nd->nd_serial_name;
+	nd->nd_serial_ttdriver->name_base = 0;
+	nd->nd_serial_ttdriver->major = 0;
+	nd->nd_serial_ttdriver->minor_start = 0;
+	nd->nd_serial_ttdriver->type = TTY_DRIVER_TYPE_SERIAL;
+	nd->nd_serial_ttdriver->subtype = SERIAL_TYPE_NORMAL;
+	nd->nd_serial_ttdriver->init_termios = DefaultTermios;
+	nd->nd_serial_ttdriver->driver_name = "dgrp";
+	nd->nd_serial_ttdriver->flags = (TTY_DRIVER_REAL_RAW |
+					 TTY_DRIVER_DYNAMIC_DEV |
+					 TTY_DRIVER_HARDWARE_BREAK);
+
+	/* The kernel wants space to store pointers to tty_structs. */
+	nd->nd_serial_ttdriver->ttys =
+		kzalloc(CHAN_MAX * sizeof(struct tty_struct *), GFP_KERNEL);
+	if (!nd->nd_serial_ttdriver->ttys)
+		return -ENOMEM;
+
+	tty_set_operations(nd->nd_serial_ttdriver, &dgrp_tty_ops);
+
+	if (!(nd->nd_ttdriver_flags & SERIAL_TTDRV_REG)) {
+		/*
+		 *   Register tty devices
+		 */
+		rc = tty_register_driver(nd->nd_serial_ttdriver);
+		if (rc < 0) {
+			/*
+			 * If errno is EBUSY, this means there are no more
+			 * slots available to have us auto-majored.
+			 * (Which is currently supported up to 256)
+			 *
+			 * We can still request majors above 256,
+			 * we just have to do it manually.
+			 */
+			if (rc == -EBUSY) {
+				int i;
+				int max_majors = 1U << (32 - MINORBITS);
+				for (i = 256; i < max_majors; i++) {
+					nd->nd_serial_ttdriver->major = i;
+					rc = tty_register_driver(nd->nd_serial_ttdriver);
+					if (rc >= 0)
+						break;
+				}
+				/* Really fail now, since we ran out
+				 * of majors to try. */
+				if (i == max_majors)
+					return rc;
+
+			} else {
+				return rc;
+			}
+		}
+		nd->nd_ttdriver_flags |= SERIAL_TTDRV_REG;
+	}
+
+	nd->nd_callout_ttdriver = alloc_tty_driver(CHAN_MAX);
+	sprintf(nd->nd_callout_name, "cu_dgrp_%s_",  id);
+
+	nd->nd_callout_ttdriver->owner = THIS_MODULE;
+	nd->nd_callout_ttdriver->name = nd->nd_callout_name;
+	nd->nd_callout_ttdriver->name_base = 0;
+	nd->nd_callout_ttdriver->major = nd->nd_serial_ttdriver->major;
+	nd->nd_callout_ttdriver->minor_start = 0x40;
+	nd->nd_callout_ttdriver->type = TTY_DRIVER_TYPE_SERIAL;
+	nd->nd_callout_ttdriver->subtype = SERIAL_TYPE_CALLOUT;
+	nd->nd_callout_ttdriver->init_termios = DefaultTermios;
+	nd->nd_callout_ttdriver->driver_name = "dgrp";
+	nd->nd_callout_ttdriver->flags = (TTY_DRIVER_REAL_RAW |
+					  TTY_DRIVER_DYNAMIC_DEV |
+					  TTY_DRIVER_HARDWARE_BREAK);
+
+	/* The kernel wants space to store pointers to tty_structs. */
+	nd->nd_callout_ttdriver->ttys =
+		kzalloc(CHAN_MAX * sizeof(struct tty_struct *), GFP_KERNEL);
+	if (!nd->nd_callout_ttdriver->ttys)
+		return -ENOMEM;
+
+	tty_set_operations(nd->nd_callout_ttdriver, &dgrp_tty_ops);
+
+	if (dgrp_register_cudevices) {
+		if (!(nd->nd_ttdriver_flags & CALLOUT_TTDRV_REG)) {
+			/*
+			 *   Register cu devices
+			 */
+			rc = tty_register_driver(nd->nd_callout_ttdriver);
+			if (rc < 0)
+				return rc;
+			nd->nd_ttdriver_flags |= CALLOUT_TTDRV_REG;
+		}
+	}
+
+
+	nd->nd_xprint_ttdriver = alloc_tty_driver(CHAN_MAX);
+	sprintf(nd->nd_xprint_name,  "pr_dgrp_%s_", id);
+
+	nd->nd_xprint_ttdriver->owner = THIS_MODULE;
+	nd->nd_xprint_ttdriver->name = nd->nd_xprint_name;
+	nd->nd_xprint_ttdriver->name_base = 0;
+	nd->nd_xprint_ttdriver->major = nd->nd_serial_ttdriver->major;
+	nd->nd_xprint_ttdriver->minor_start = 0x80;
+	nd->nd_xprint_ttdriver->type = TTY_DRIVER_TYPE_SERIAL;
+	nd->nd_xprint_ttdriver->subtype = SERIAL_TYPE_XPRINT;
+	nd->nd_xprint_ttdriver->init_termios = DefaultTermios;
+	nd->nd_xprint_ttdriver->driver_name = "dgrp";
+	nd->nd_xprint_ttdriver->flags = (TTY_DRIVER_REAL_RAW |
+					 TTY_DRIVER_DYNAMIC_DEV |
+					 TTY_DRIVER_HARDWARE_BREAK);
+
+	/* The kernel wants space to store pointers to tty_structs. */
+	nd->nd_xprint_ttdriver->ttys =
+		kzalloc(CHAN_MAX * sizeof(struct tty_struct *), GFP_KERNEL);
+	if (!nd->nd_xprint_ttdriver->ttys)
+		return -ENOMEM;
+
+	tty_set_operations(nd->nd_xprint_ttdriver, &dgrp_tty_ops);
+
+	if (dgrp_register_prdevices) {
+		if (!(nd->nd_ttdriver_flags & XPRINT_TTDRV_REG)) {
+			/*
+			 *   Register transparent print devices
+			 */
+			rc = tty_register_driver(nd->nd_xprint_ttdriver);
+			if (rc < 0)
+				return rc;
+			nd->nd_ttdriver_flags |= XPRINT_TTDRV_REG;
+		}
+	}
+
+	for (i = 0; i < CHAN_MAX; i++) {
+		struct ch_struct *ch = nd->nd_chan + i;
+
+		ch->ch_nd = nd;
+		ch->ch_digi = digi_init;
+		ch->ch_edelay = 100;
+		ch->ch_custom_speed = 0;
+		ch->ch_portnum = i;
+		ch->ch_tun.un_ch = ch;
+		ch->ch_pun.un_ch = ch;
+		ch->ch_tun.un_type = SERIAL_TYPE_NORMAL;
+		ch->ch_pun.un_type = SERIAL_TYPE_XPRINT;
+
+		init_waitqueue_head(&(ch->ch_flag_wait));
+		init_waitqueue_head(&(ch->ch_sleep));
+
+		init_waitqueue_head(&(ch->ch_tun.un_open_wait));
+		init_waitqueue_head(&(ch->ch_tun.un_close_wait));
+
+		init_waitqueue_head(&(ch->ch_pun.un_open_wait));
+		init_waitqueue_head(&(ch->ch_pun.un_close_wait));
+		tty_port_init(&ch->port);
+		tty_port_init(&ch->port);
+	}
+	return 0;
+}
diff --git a/drivers/staging/dgrp/digirp.h b/drivers/staging/dgrp/digirp.h
new file mode 100644
index 000000000000..33c1394fade7
--- /dev/null
+++ b/drivers/staging/dgrp/digirp.h
@@ -0,0 +1,129 @@
+/************************************************************************
+ * HP-UX Realport Daemon interface file.
+ *
+ * Copyright (C) 1998, by Digi International.  All Rights Reserved.
+ ************************************************************************/
+
+#ifndef _DIGIDRP_H
+#define _DIGIDRP_H
+
+/************************************************************************
+ * This file contains defines for the ioctl() interface to
+ * the realport driver.   This ioctl() interface is used by the
+ * daemon to set speed setup parameters honored by the driver.
+ ************************************************************************/
+
+struct link_struct {
+	int lk_fast_rate;  /* Fast line rate to be used
+			      when the delay is less-equal
+			      to lk_fast_delay */
+
+	int lk_fast_delay; /* Fast line rate delay in
+			      milliseconds */
+
+	int lk_slow_rate;  /* Slow line rate to be used when
+			      the delay is greater-equal
+			      to lk_slow_delay */
+
+	int lk_slow_delay; /* Slow line rate delay in
+			      milliseconds */
+
+	int lk_header_size; /* Estimated packet header size
+			       when sent across the slowest
+			       link.  */
+};
+
+#define DIGI_GETLINK	_IOW('e', 103, struct link_struct)	/* Get link parameters */
+#define DIGI_SETLINK	_IOW('e', 104, struct link_struct)	/* Set link parameters */
+
+
+/************************************************************************
+ * This module provides application access to special Digi
+ * serial line enhancements which are not standard UNIX(tm) features.
+ ************************************************************************/
+
+struct	digiflow_struct {
+	unsigned char	startc;				/* flow cntl start char	*/
+	unsigned char	stopc;				/* flow cntl stop char	*/
+};
+
+/************************************************************************
+ * Values for digi_flags
+ ************************************************************************/
+#define DIGI_IXON	0x0001		/* Handle IXON in the FEP	*/
+#define DIGI_FAST	0x0002		/* Fast baud rates		*/
+#define RTSPACE		0x0004		/* RTS input flow control	*/
+#define CTSPACE		0x0008		/* CTS output flow control	*/
+#define DSRPACE		0x0010		/* DSR output flow control	*/
+#define DCDPACE		0x0020		/* DCD output flow control	*/
+#define DTRPACE		0x0040		/* DTR input flow control	*/
+#define DIGI_COOK	0x0080		/* Cooked processing done in FEP */
+#define DIGI_FORCEDCD	0x0100		/* Force carrier		*/
+#define	DIGI_ALTPIN	0x0200		/* Alternate RJ-45 pin config	*/
+#define	DIGI_AIXON	0x0400		/* Aux flow control in fep	*/
+#define	DIGI_PRINTER	0x0800		/* Hold port open for flow cntrl */
+#define DIGI_PP_INPUT	0x1000		/* Change parallel port to input */
+#define DIGI_422	0x4000		/* Change parallel port to input */
+#define DIGI_RTS_TOGGLE	0x8000		/* Support RTS Toggle		 */
+
+
+/************************************************************************
+ * Values associated with transparent print
+ ************************************************************************/
+#define DIGI_PLEN	8		/* String length */
+#define	DIGI_TSIZ	10		/* Terminal string len */
+
+
+/************************************************************************
+ * Structure used with ioctl commands for DIGI parameters.
+ ************************************************************************/
+struct digi_struct {
+	unsigned short	digi_flags;		/* Flags (see above)	*/
+	unsigned short	digi_maxcps;		/* Max printer CPS	*/
+	unsigned short	digi_maxchar;		/* Max chars in print queue */
+	unsigned short	digi_bufsize;		/* Buffer size		*/
+	unsigned char	digi_onlen;		/* Length of ON string	*/
+	unsigned char	digi_offlen;		/* Length of OFF string	*/
+	char		digi_onstr[DIGI_PLEN];	/* Printer on string	*/
+	char		digi_offstr[DIGI_PLEN];	/* Printer off string	*/
+	char		digi_term[DIGI_TSIZ];	/* terminal string	*/
+};
+
+/************************************************************************
+ * Ioctl command arguments for DIGI parameters.
+ ************************************************************************/
+/* Read params */
+#define DIGI_GETA	_IOR('e', 94, struct digi_struct)
+
+/* Set params */
+#define DIGI_SETA	_IOW('e', 95, struct digi_struct)
+
+/* Drain & set params	*/
+#define DIGI_SETAW	_IOW('e', 96, struct digi_struct)
+
+/* Drain, flush & set params */
+#define DIGI_SETAF	_IOW('e', 97, struct digi_struct)
+
+/* Get startc/stopc flow control characters */
+#define	DIGI_GETFLOW	_IOR('e', 99, struct digiflow_struct)
+
+/* Set startc/stopc flow control characters */
+#define	DIGI_SETFLOW	_IOW('e', 100, struct digiflow_struct)
+
+/* Get Aux. startc/stopc flow control chars */
+#define	DIGI_GETAFLOW	_IOR('e', 101, struct digiflow_struct)
+
+/* Set Aux. startc/stopc flow control chars */
+#define	DIGI_SETAFLOW	_IOW('e', 102, struct digiflow_struct)
+
+/* Set integer baud rate */
+#define	DIGI_SETCUSTOMBAUD	_IOW('e', 106, int)
+
+/* Get integer baud rate */
+#define	DIGI_GETCUSTOMBAUD	_IOR('e', 107, int)
+
+#define	DIGI_GEDELAY	_IOR('d', 246, int)	/* Get edelay */
+#define	DIGI_SEDELAY	_IOW('d', 247, int)	/* Get edelay */
+
+
+#endif /* _DIGIDRP_H */
diff --git a/drivers/staging/dgrp/drp.h b/drivers/staging/dgrp/drp.h
new file mode 100644
index 000000000000..84a1e7be4899
--- /dev/null
+++ b/drivers/staging/dgrp/drp.h
@@ -0,0 +1,693 @@
+/*
+ *
+ * Copyright 1999 Digi International (www.digi.com)
+ *     Gene Olson  <gene at digi dot com>
+ *     James Puzzo <jamesp at digi dot com>
+ *     Scott Kilau <scottk at digi dot com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED; without even the
+ * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+ * PURPOSE.  See the GNU General Public License for more details.
+ *
+ */
+
+/************************************************************************
+ * Master include file for Linux Realport Driver.
+ ************************************************************************/
+
+#ifndef __DRP_H
+#define __DRP_H
+
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/semaphore.h>
+#include <linux/tty.h>
+
+
+#include "digirp.h"
+
+/************************************************************************
+ * Tuning parameters.
+ ************************************************************************/
+
+#define CHAN_MAX	64		/* Max # ports per server */
+
+#define SEQ_MAX		128		/* Max # transmit sequences (2^n) */
+#define SEQ_MASK	(SEQ_MAX-1)	/* Sequence buffer modulus mask */
+
+#define TBUF_MAX	4096		/* Size of transmit buffer (2^n) */
+#define RBUF_MAX	4096		/* Size of receive buffer (2^n) */
+
+#define TBUF_MASK	(TBUF_MAX-1)	/* Transmit buffer modulus mask */
+#define RBUF_MASK	(RBUF_MAX-1)	/* Receive buffer modulus mask */
+
+#define TBUF_LOW	1000		/* Transmit low water mark */
+
+#define UIO_BASE	1000		/* Base for write operations */
+#define UIO_MIN		2000		/* Minimum size application buffer */
+#define UIO_MAX		8100		/* Unix I/O buffer size */
+
+#define MON_MAX		65536		/* Monitor buffer size (2^n) */
+#define MON_MASK	(MON_MAX-1)	/* Monitor wrap mask */
+
+#define DPA_MAX		65536		/* DPA buffer size (2^n) */
+#define DPA_MASK	(DPA_MAX-1)	/* DPA wrap mask */
+#define DPA_HIGH_WATER	58000		/* Enforce flow control when
+					 * over this amount
+					 */
+
+#define IDLE_MAX	(20 * HZ)	/* Max TCP link idle time */
+
+#define MAX_DESC_LEN	100		/* Maximum length of stored PS
+					 * description
+					 */
+
+#define WRITEBUFLEN	((4096) + 4)    /* 4 extra for alignment play space */
+
+#define VPDSIZE		512
+
+/************************************************************************
+ * Minor device decoding conventions.
+ ************************************************************************
+ *
+ * For Linux, the net and mon devices are handled via "proc", so we
+ * only have to mux the "tty" devices.  Since every PortServer will
+ * have an individual major number, the PortServer number does not
+ * need to be encoded, and in fact, does not need to exist.
+ *
+ */
+
+/*
+ * Port device decoding conventions:
+ *
+ *	Device 00 - 3f        64 dial-in modem devices. (tty)
+ *	Device 40 - 7f        64 dial-out tty devices.  (cu)
+ *	Device 80 - bf        64 dial-out printer devices.
+ *
+ *  IS_PRINT(dev)		This is a printer device.
+ *
+ *  OPEN_CATEGORY(dev)		Specifies the device category.  No two
+ *				devices of different categories may be open
+ *				at the same time.
+ *
+ * The following require the category returned by OPEN_CATEGORY().
+ *
+ *  OPEN_WAIT_AVAIL(cat)	Waits on open until the device becomes
+ *				available.  Fails if NDELAY specified.
+ *
+ *  OPEN_WAIT_CARRIER(cat)	Waits on open if carrier is not present.
+ *				Succeeds if NDELAY is given.
+ *
+ *  OPEN_FORCES_CARRIER(cat)	Carrier is forced high on open.
+ *
+ */
+
+#define PORT_NUM(dev)			((dev) & 0x3f)
+
+#define OPEN_CATEGORY(dev)		((((dev) & 0x80) & 0x40))
+#define IS_PRINT(dev)			(((dev) & 0xff) >= 0x80)
+
+#define OPEN_WAIT_AVAIL(cat)		(((cat) & 0x40) == 0x000)
+#define OPEN_WAIT_CARRIER(cat)		(((cat) & 0x40) == 0x000)
+#define OPEN_FORCES_CARRIER(cat)	(((cat) & 0x40) != 0x000)
+
+
+/************************************************************************
+ * Modem signal defines for 16450/16550 compatible FEP.
+ * set in ch_mout, ch_mflow, ch_mlast etc
+ ************************************************************************/
+
+/* TODO : Re-verify that these modem signal definitions are correct */
+
+#define DM_DTR		0x01
+#define DM_RTS		0x02
+#define DM_RTS_TOGGLE	0x04
+
+#define DM_OUT1		0x04
+#define DM_OUT2		0x08
+
+#define DM_CTS		0x10
+#define DM_DSR		0x20
+#define DM_RI		0x40
+#define DM_CD		0x80		/* This is the DCD flag */
+
+
+/************************************************************************
+ * Realport Event Flags.
+ ************************************************************************/
+
+#define EV_OPU		0x0001		/* Ouput paused by client */
+#define EV_OPS		0x0002		/* Output paused by XOFF */
+#define EV_OPX		0x0004		/* Output paused by XXOFF */
+#define EV_OPH		0x0008		/* Output paused by MFLOW */
+#define EV_IPU		0x0010		/* Input paused by client */
+#define EV_IPS		0x0020		/* Input paused by hi/low water */
+#define EV_TXB		0x0040		/* Transmit break pending */
+#define EV_TXI		0x0080		/* Transmit immediate pending */
+#define EV_TXF		0x0100		/* Transmit flow control pending */
+#define EV_RXB		0x0200		/* Break received */
+
+
+/************************************************************************
+ * Realport CFLAGS.
+ ************************************************************************/
+
+#define CF_CS5		0x0000		/* 5 bit characters */
+#define CF_CS6		0x0010		/* 6 bit characters */
+#define CF_CS7		0x0020		/* 7 bit characters */
+#define CF_CS8		0x0030		/* 8 bit characters */
+#define CF_CSIZE	0x0030		/* Character size */
+#define CF_CSTOPB	0x0040		/* Two stop bits */
+#define CF_CREAD	0x0080		/* Enable receiver */
+#define CF_PARENB	0x0100		/* Enable parity */
+#define CF_PARODD	0x0200		/* Odd parity */
+#define CF_HUPCL	0x0400		/* Drop DTR on close */
+
+
+/************************************************************************
+ * Realport XFLAGS.
+ ************************************************************************/
+
+#define XF_XPAR		0x0001		/* Enable Mark/Space Parity */
+#define XF_XMODEM	0x0002		/* Enable in-band modem signalling */
+#define XF_XCASE	0x0004		/* Convert special characters */
+#define XF_XEDATA	0x0008		/* Error data in stream */
+#define XF_XTOSS	0x0010		/* Toss IXANY characters */
+#define XF_XIXON	0x0020		/* xxon/xxoff enable */
+
+
+/************************************************************************
+ * Realport IFLAGS.
+ ************************************************************************/
+
+#define IF_IGNBRK	0x0001		/* Ignore input break */
+#define IF_BRKINT	0x0002		/* Break interrupt */
+#define IF_IGNPAR	0x0004		/* Ignore error characters */
+#define IF_PARMRK	0x0008		/* Error chars marked with 0xff */
+#define IF_INPCK	0x0010		/* Input parity checking enabled */
+#define IF_ISTRIP	0x0020		/* Input chars masked with 0x7F */
+#define IF_IXON		0x0400		/* Output software flow control */
+#define IF_IXANY	0x0800		/* Restart output on any char */
+#define	IF_IXOFF	0x1000		/* Input software flow control */
+#define IF_DOSMODE	0x8000		/* 16450-compatible errors */
+
+
+/************************************************************************
+ * Realport OFLAGS.
+ ************************************************************************/
+
+#define OF_OLCUC	0x0002		/* Map lower to upper case */
+#define OF_ONLCR	0x0004		/* Map NL to CR-NL */
+#define OF_OCRNL	0x0008		/* Map CR to NL */
+#define OF_ONOCR	0x0010		/* No CR output at column 0 */
+#define OF_ONLRET	0x0020		/* Assume NL does NL/CR */
+#define OF_TAB3		0x1800		/* Tabs expand to 8 spaces */
+#define OF_TABDLY	0x1800		/* Tab delay */
+
+/************************************************************************
+ * Unit flag definitions for un_flag.
+ ************************************************************************/
+
+/* These are the DIGI unit flags */
+#define UN_EXCL		0x00010000	/* Exclusive open */
+#define UN_STICKY	0x00020000	/* TTY Settings are now sticky */
+#define UN_BUSY		0x00040000	/* Some work this channel */
+#define UN_PWAIT	0x00080000	/* Printer waiting for terminal */
+#define UN_TIME		0x00100000	/* Waiting on time */
+#define UN_EMPTY	0x00200000	/* Waiting output queue empty */
+#define UN_LOW		0x00400000	/* Waiting output low water */
+#define UN_DIGI_MASK	0x00FF0000	/* Waiting output low water */
+
+/*
+ * Definitions for async_struct (and serial_struct) flags field
+ *
+ * these are the ASYNC flags copied from serial.h
+ *
+ */
+#define UN_HUP_NOTIFY	0x0001 /* Notify getty on hangups and
+				* closes on the callout port
+				*/
+#define UN_FOURPORT	0x0002	/* Set OU1, OUT2 per AST Fourport settings */
+#define UN_SAK		0x0004	/* Secure Attention Key (Orange book) */
+#define UN_SPLIT_TERMIOS 0x0008 /* Separate termios for dialin/callout */
+
+#define UN_SPD_MASK	0x0030
+#define UN_SPD_HI	0x0010	/* Use 56000 instead of 38400 bps */
+#define UN_SPD_VHI	0x0020	/* Use 115200 instead of 38400 bps */
+#define UN_SPD_CUST	0x0030	/* Use user-specified divisor */
+
+#define UN_SKIP_TEST	0x0040 /* Skip UART test during autoconfiguration */
+#define UN_AUTO_IRQ	0x0080 /* Do automatic IRQ during autoconfiguration */
+
+#define UN_SESSION_LOCKOUT 0x0100 /* Lock out cua opens based on session */
+#define UN_PGRP_LOCKOUT	   0x0200 /* Lock out cua opens based on pgrp */
+#define UN_CALLOUT_NOHUP   0x0400 /* Don't do hangups for cua device */
+
+#define UN_FLAGS	0x0FFF	/* Possible legal async flags */
+#define UN_USR_MASK	0x0430	/* Legal flags that non-privileged
+				 * users can set or reset
+				 */
+
+#define UN_INITIALIZED		0x80000000 /* Serial port was initialized */
+#define UN_CALLOUT_ACTIVE	0x40000000 /* Call out device is active */
+#define UN_NORMAL_ACTIVE	0x20000000 /* Normal device is active */
+#define UN_BOOT_AUTOCONF	0x10000000 /* Autoconfigure port on bootup */
+#define UN_CLOSING		0x08000000 /* Serial port is closing */
+#define UN_CTS_FLOW		0x04000000 /* Do CTS flow control */
+#define UN_CHECK_CD		0x02000000 /* i.e., CLOCAL */
+#define UN_SHARE_IRQ		0x01000000 /* for multifunction cards */
+
+
+/************************************************************************
+ * Structure for terminal or printer unit.  struct un_struct
+ *
+ * Note that in some places the code assumes the "tty_t" is placed
+ * first in the structure.
+ ************************************************************************/
+
+struct un_struct {
+	struct tty_struct *un_tty;		/* System TTY struct */
+	struct ch_struct *un_ch;		/* Associated channel */
+
+	ushort     un_open_count;		/* Successful open count */
+	int		un_flag;		/* Unit flags */
+	ushort     un_tbusy;		/* Busy transmit count */
+
+	wait_queue_head_t  un_open_wait;
+	wait_queue_head_t  un_close_wait;
+	ushort	un_type;
+	struct device *un_sysfs;
+};
+
+
+/************************************************************************
+ * Channel State Numbers for ch_state.
+ ************************************************************************/
+
+/*
+ * The ordering is important.
+ *
+ *    state <= CS_WAIT_CANCEL implies the channel is definitely closed.
+ *
+ *    state >= CS_WAIT_FAIL  implies the channel is definitely open.
+ *
+ *    state >= CS_READY implies data is allowed on the channel.
+ */
+
+enum dgrp_ch_state_t {
+	CS_IDLE = 0,	    /* Channel is idle */
+	CS_WAIT_OPEN = 1,   /* Waiting for Immediate Open Resp */
+	CS_WAIT_CANCEL = 2, /* Waiting for Per/Incom Cancel Resp */
+	CS_WAIT_FAIL = 3,   /* Waiting for Immed Open Failure */
+	CS_SEND_QUERY = 4,  /* Ready to send Port Query */
+	CS_WAIT_QUERY = 5,  /* Waiting for Port Query Response */
+	CS_READY = 6,	    /* Ready to accept commands and data */
+	CS_SEND_CLOSE =	7,  /* Ready to send Close Request */
+	CS_WAIT_CLOSE =	8   /* Waiting for Close Response */
+};
+
+/************************************************************************
+ * Device flag definitions for ch_flag.
+ ************************************************************************/
+
+/*
+ *  Note that the state of the two carrier based flags is key.	When
+ *  we check for carrier state transitions, we look at the current
+ *  physical state of the DCD line and compare it with PHYS_CD (which
+ *  was the state the last time we checked), and we also determine
+ *  a new virtual state (composite of the physical state, FORCEDCD,
+ *  CLOCAL, etc.) and compare it with VIRT_CD.
+ *
+ *  VIRTUAL transitions high will have the side effect of waking blocked
+ *  opens.
+ *
+ *  PHYSICAL transitions low will cause hangups to occur _IF_ the virtual
+ *  state is also low.	We DON'T want to hangup on a PURE virtual drop.
+ */
+
+#define CH_HANGUP	0x00002		/* Server port ready to close */
+
+#define CH_VIRT_CD	0x00004		/* Carrier was virtually present */
+#define CH_PHYS_CD	0x00008		/* Carrier was physically present */
+
+#define CH_CLOCAL	0x00010		/* CLOCAL set in cflags */
+#define CH_BAUD0	0x00020		/* Baud rate zero hangup */
+
+#define CH_FAST_READ	0x00040		/* Fast reads are enabled */
+#define CH_FAST_WRITE	0x00080		/* Fast writes are enabled */
+
+#define CH_PRON		0x00100		/* Printer on string active */
+#define CH_RX_FLUSH	0x00200		/* Flushing receive data */
+#define CH_LOW		0x00400		/* Thread waiting for LOW water */
+#define CH_EMPTY	0x00800		/* Thread waiting for EMPTY */
+#define CH_DRAIN	0x01000		/* Close is waiting to drain */
+#define CH_INPUT	0x02000		/* Thread waiting for INPUT */
+#define CH_RXSTOP	0x04000		/* Stop output to ldisc */
+#define CH_PARAM	0x08000		/* A parameter was updated */
+#define CH_WAITING_SYNC 0x10000		/* A pending sync was assigned
+					 * to this port.
+					 */
+#define CH_PORT_GONE	0x20000		/* Port has disappeared */
+#define CH_TX_BREAK	0x40000		/* TX Break to be sent,
+					 * but has not yet.
+					 */
+
+/************************************************************************
+ * Types of Open Requests for ch_otype.
+ ************************************************************************/
+
+#define OTYPE_IMMEDIATE	  0		/* Immediate Open */
+#define OTYPE_PERSISTENT  1		/* Persistent Open */
+#define OTYPE_INCOMING	  2		/* Incoming Open */
+
+
+/************************************************************************
+ * Request/Response flags.
+ ************************************************************************/
+
+#define RR_SEQUENCE	0x0001		/* Get server RLAST, TIN */
+#define RR_STATUS	0x0002		/* Get server MINT, EINT */
+#define RR_BUFFER	0x0004		/* Get server RSIZE, TSIZE */
+#define RR_CAPABILITY	0x0008		/* Get server port capabilities */
+
+#define RR_TX_FLUSH	0x0040		/* Flush output buffers */
+#define RR_RX_FLUSH	0x0080		/* Flush input buffers */
+
+#define RR_TX_STOP	0x0100		/* Pause output */
+#define RR_RX_STOP	0x0200		/* Pause input */
+#define RR_TX_START	0x0400		/* Start output */
+#define RR_RX_START	0x0800		/* Start input */
+
+#define RR_TX_BREAK	0x1000		/* Send BREAK */
+#define RR_TX_ICHAR	0x2000		/* Send character immediate */
+
+
+/************************************************************************
+ * Channel information structure.   struct ch_struct
+ ************************************************************************/
+
+struct ch_struct {
+	struct digi_struct ch_digi;		/* Digi variables */
+	int	ch_edelay;		/* Digi edelay */
+
+	struct tty_port port;
+	struct un_struct ch_tun;	/* Terminal unit info */
+	struct un_struct ch_pun;	/* Printer unit info */
+
+	struct nd_struct *ch_nd;	/* Node pointer */
+	u8  *ch_tbuf;		/* Local Transmit Buffer */
+	u8  *ch_rbuf;		/* Local Receive Buffer */
+	ulong	ch_cpstime;		/* Printer CPS time */
+	ulong	ch_waketime;		/* Printer wake time */
+
+	ulong	ch_flag;		/* CH_* flags */
+
+	enum dgrp_ch_state_t ch_state;		/* CS_* Protocol state */
+	ushort	ch_send;		/* Bit vector of RR_* requests */
+	ushort	ch_expect;		/* Bit vector of RR_* responses */
+	ushort	ch_wait_carrier;	/* Thread count waiting for carrier */
+	ushort	ch_wait_count[3];	/* Thread count waiting by otype */
+
+	ushort	ch_portnum;		/* Port number */
+	ushort	ch_open_count;		/* Successful open count */
+	ushort	ch_category;		/* Device category */
+	ushort	ch_open_error;		/* Last open error number */
+	ushort	ch_break_time;		/* Pending break request time */
+	ushort	ch_cpsrem;		/* Printer CPS remainder */
+	ushort	ch_ocook;		/* Realport fastcook oflags */
+	ushort	ch_inwait;		/* Thread count in CLIST input */
+
+	ushort	ch_tin;			/* Local transmit buffer in ptr */
+	ushort	ch_tout;		/* Local transmit buffer out ptr */
+	ushort	ch_s_tin;		/* Realport TIN */
+	ushort	ch_s_tpos;		/* Realport TPOS */
+	ushort	ch_s_tsize;		/* Realport TSIZE */
+	ushort	ch_s_treq;		/* Realport TREQ */
+	ushort	ch_s_elast;		/* Realport ELAST */
+
+	ushort	ch_rin;			/* Local receive buffer in ptr */
+	ushort	ch_rout;		/* Local receive buffer out ptr */
+	ushort	ch_s_rin;		/* Realport RIN */
+	/* David Fries 7-13-2001, ch_s_rin should be renamed ch_s_rout because
+	 * the variable we want to represent is the PortServer's ROUT, which is
+	 * the sequence number for the next byte the PortServer will send us.
+	 * RIN is the sequence number for the next byte the PortServer will
+	 * receive from the uart.  The port server will send data as long as
+	 * ROUT is less than RWIN.  What would happen is the port is opened, it
+	 * receives data, it gives the value of RIN, we set the RWIN to
+	 * RIN+RBUF_MAX-1, it sends us RWIN-ROUT bytes which overflows.	 ROUT
+	 * is set to zero when the port is opened, so we start at zero and
+	 * count up as data is received.
+	 */
+	ushort	ch_s_rwin;		/* Realport RWIN */
+	ushort	ch_s_rsize;		/* Realport RSIZE */
+
+	ushort	ch_tmax;		/* Local TMAX */
+	ushort	ch_ttime;		/* Local TTIME */
+	ushort	ch_rmax;		/* Local RMAX */
+	ushort	ch_rtime;		/* Local RTIME */
+	ushort	ch_rlow;		/* Local RLOW */
+	ushort	ch_rhigh;		/* Local RHIGH */
+
+	ushort	ch_s_tmax;		/* Realport TMAX */
+	ushort	ch_s_ttime;		/* Realport TTIME */
+	ushort	ch_s_rmax;		/* Realport RMAX */
+	ushort	ch_s_rtime;		/* Realport RTIME */
+	ushort	ch_s_rlow;		/* Realport RLOW */
+	ushort	ch_s_rhigh;		/* Realport RHIGH */
+
+	ushort	ch_brate;		/* Local baud rate */
+	ushort	ch_cflag;		/* Local tty cflags */
+	ushort	ch_iflag;		/* Local tty iflags */
+	ushort	ch_oflag;		/* Local tty oflags */
+	ushort	ch_xflag;		/* Local tty xflags */
+
+	ushort	ch_s_brate;		/* Realport BRATE */
+	ushort	ch_s_cflag;		/* Realport CFLAG */
+	ushort	ch_s_iflag;		/* Realport IFLAG */
+	ushort	ch_s_oflag;		/* Realport OFLAG */
+	ushort	ch_s_xflag;		/* Realport XFLAG */
+
+	u8	ch_otype;		/* Open request type */
+	u8	ch_pscan_savechar;	/* Last character read by parity scan */
+	u8	ch_pscan_state;		/* PScan State based on last 2 chars */
+	u8	ch_otype_waiting;	/* Type of open pending in server */
+	u8	ch_flush_seq;		/* Receive flush end sequence */
+	u8	ch_s_mlast;		/* Realport MLAST */
+
+	u8	ch_mout;		/* Local MOUT */
+	u8	ch_mflow;		/* Local MFLOW */
+	u8	ch_mctrl;		/* Local MCTRL */
+	u8	ch_xon;			/* Local XON */
+	u8	ch_xoff;		/* Local XOFF */
+	u8	ch_lnext;		/* Local LNEXT */
+	u8	ch_xxon;		/* Local XXON */
+	u8	ch_xxoff;		/* Local XXOFF */
+
+	u8	ch_s_mout;		/* Realport MOUT */
+	u8	ch_s_mflow;		/* Realport MFLOW */
+	u8	ch_s_mctrl;		/* Realport MCTRL */
+	u8	ch_s_xon;		/* Realport XON */
+	u8	ch_s_xoff;		/* Realport XOFF */
+	u8	ch_s_lnext;		/* Realport LNEXT */
+	u8	ch_s_xxon;		/* Realport XXON */
+	u8	ch_s_xxoff;		/* Realport XXOFF */
+
+	wait_queue_head_t ch_flag_wait;	/* Wait queue for ch_flag changes */
+	wait_queue_head_t ch_sleep;	/* Wait queue for my_sleep() */
+
+	int	ch_custom_speed;	/* Realport custom speed */
+	int	ch_txcount;		/* Running TX count */
+	int	ch_rxcount;		/* Running RX count */
+};
+
+
+/************************************************************************
+ * Node State definitions.
+ ************************************************************************/
+
+enum dgrp_nd_state_t {
+	NS_CLOSED = 0,	   /* Network device is closed */
+	NS_IDLE = 1,	   /* Network connection inactive */
+	NS_SEND_QUERY =	2, /* Send server query */
+	NS_WAIT_QUERY =	3, /* Wait for query response */
+	NS_READY = 4,	   /* Network ready */
+	NS_SEND_ERROR =	5  /* Must send error hangup */
+};
+
+#define ND_STATE_STR(x) \
+	((x) == NS_CLOSED     ? "CLOSED"     : \
+	((x) == NS_IDLE	      ? "IDLE"	     : \
+	((x) == NS_SEND_QUERY ? "SEND_QUERY" : \
+	((x) == NS_WAIT_QUERY ? "WAIT_QUERY" : \
+	((x) == NS_READY      ? "READY"	     : \
+	((x) == NS_SEND_ERROR ? "SEND_ERROR" : "UNKNOWN"))))))
+
+/************************************************************************
+ * Node Flag definitions.
+ ************************************************************************/
+
+#define ND_SELECT	0x0001		/* Multiple net read selects */
+#define ND_DEB_WAIT	0x0002		/* Debug Device waiting */
+
+
+/************************************************************************
+ * Monitoring flag definitions.
+ ************************************************************************/
+
+#define MON_WAIT_DATA	0x0001		/* Waiting for buffer data */
+#define MON_WAIT_SPACE	0x0002		/* Waiting for buffer space */
+
+/************************************************************************
+ * DPA flag definitions.
+ ************************************************************************/
+
+#define DPA_WAIT_DATA	0x0001		/* Waiting for buffer data */
+#define DPA_WAIT_SPACE	0x0002		/* Waiting for buffer space */
+
+
+/************************************************************************
+ * Definitions taken from Realport Dump.
+ ************************************************************************/
+
+#define RPDUMP_MAGIC	"Digi-RealPort-1.0"
+
+#define RPDUMP_MESSAGE	0xE2		/* Descriptive message */
+#define RPDUMP_RESET	0xE7		/* Connection reset */
+#define RPDUMP_CLIENT	0xE8		/* Client data */
+#define RPDUMP_SERVER	0xE9		/* Server data */
+
+
+/************************************************************************
+ * Node request/response definitions.
+ ************************************************************************/
+
+#define NR_ECHO		0x0001		/* Server echo packet */
+#define NR_IDENT	0x0002		/* Server Product ID */
+#define NR_CAPABILITY	0x0004		/* Server Capabilties */
+#define NR_VPD		0x0008		/* Server VPD, if any */
+#define NR_PASSWORD	0x0010		/* Server Password */
+
+/************************************************************************
+ * Registration status of the node's Linux struct tty_driver structures.
+ ************************************************************************/
+#define SERIAL_TTDRV_REG   0x0001     /* nd_serial_ttdriver registered	*/
+#define CALLOUT_TTDRV_REG  0x0002     /* nd_callout_ttdriver registered */
+#define XPRINT_TTDRV_REG   0x0004     /* nd_xprint_ttdriver registered	*/
+
+
+/************************************************************************
+ * Node structure.  There exists one of these for each associated
+ * realport server.
+ ************************************************************************/
+
+struct nd_struct {
+	struct list_head	list;
+	long	      nd_major;		   /* Node's major number	    */
+	long	      nd_ID;		   /* Node's ID code		    */
+
+	char	      nd_serial_name[50];   /* "tty_dgrp_<id>_" + null	    */
+	char	      nd_callout_name[50];  /* "cu_dgrp_<id>_" + null	    */
+	char	      nd_xprint_name[50];   /* "pr_dgrp_<id>_" + null	    */
+
+	char	     password[16];	  /* Password for server, if needed */
+	int	     nd_tty_ref_cnt;	  /* Linux tty reference count	   */
+
+	struct proc_dir_entry *nd_net_de; /* Dir entry for /proc/dgrp/net  */
+	struct proc_dir_entry *nd_mon_de; /* Dir entry for /proc/dgrp/mon  */
+	struct proc_dir_entry *nd_ports_de; /* Dir entry for /proc/dgrp/ports*/
+	struct proc_dir_entry *nd_dpa_de; /* Dir entry for /proc/dgrp/dpa  */
+
+	spinlock_t nd_lock;		  /* General node lock		   */
+
+	struct semaphore nd_net_semaphore; /* Net read/write lock	    */
+	struct semaphore nd_mon_semaphore; /* Monitor buffer lock	    */
+	spinlock_t nd_dpa_lock;		/* DPA buffer lock	     */
+
+	enum dgrp_nd_state_t nd_state;	  /* NS_* network state */
+	int	      nd_chan_count;	   /* # active channels		    */
+	int	      nd_flag;		   /* Node flags		    */
+	int	      nd_send;		   /* Responses to send		    */
+	int	      nd_expect;	   /* Responses we expect	    */
+
+	u8	 *nd_iobuf;	       /* Network R/W Buffer		*/
+	wait_queue_head_t nd_tx_waitq;	  /* Network select wait queue	   */
+
+	u8	 *nd_inputbuf;	       /* Input Buffer			*/
+	u8	 *nd_inputflagbuf;     /* Input Flags Buffer		*/
+
+	int	      nd_tx_deposit;	   /* Accumulated transmit deposits */
+	int	      nd_tx_charge;	   /* Accumulated transmit charges  */
+	int	      nd_tx_credit;	   /* Current TX credit		    */
+	int	      nd_tx_ready;	   /* Ready to transmit		    */
+	int	      nd_tx_work;	   /* TX work waiting		    */
+	ulong	     nd_tx_time;	  /* Last transmit time		   */
+	ulong	     nd_poll_time;	  /* Next scheduled poll time	   */
+
+	int	      nd_delay;		   /* Current TX delay		    */
+	int	      nd_rate;		   /* Current TX rate		    */
+	struct link_struct nd_link;		/* Link speed params.		 */
+
+	int	      nd_seq_in;	   /* TX seq in ptr		    */
+	int	      nd_seq_out;	   /* TX seq out ptr		    */
+	int	      nd_unack;		   /* Unacknowledged byte count	    */
+	int	      nd_remain;	   /* Remaining receive bytes	    */
+	int	      nd_tx_module;	   /* Current TX module #	    */
+	int	      nd_rx_module;	   /* Current RX module #	    */
+	char	     *nd_error;		   /* Protocol error message	    */
+
+	int	      nd_write_count;	   /* drp_write() call count	    */
+	int	      nd_read_count;	   /* drp_read() count		    */
+	int	      nd_send_count;	   /* TCP message sent		    */
+	int	      nd_tx_byte;	   /* Transmit byte count	    */
+	int	      nd_rx_byte;	   /* Receive byte count	    */
+
+	ulong	     nd_mon_lbolt;	 /* Monitor start time		   */
+	int	      nd_mon_flag;	  /* Monitor flags		    */
+	int	      nd_mon_in;	  /* Monitor in pointer		    */
+	int	      nd_mon_out;	  /* Monitor out pointer	    */
+	wait_queue_head_t nd_mon_wqueue;  /* Monitor wait queue (on flags)  */
+	u8	 *nd_mon_buf;	      /* Monitor buffer			*/
+
+	ulong	     nd_dpa_lbolt;	/* DPA start time	      */
+	int	     nd_dpa_flag;	/* DPA flags		      */
+	int	     nd_dpa_in;		/* DPA in pointer	      */
+	int	     nd_dpa_out;	/* DPA out pointer	      */
+	wait_queue_head_t nd_dpa_wqueue; /* DPA wait queue (on flags)  */
+	u8	  *nd_dpa_buf;	/* DPA buffer		      */
+
+	uint	     nd_dpa_debug;
+	uint	     nd_dpa_port;
+
+	wait_queue_head_t nd_seq_wque[SEQ_MAX];	  /* TX thread wait queues */
+	u8	  nd_seq_wait[SEQ_MAX];	  /* Transmit thread wait count */
+
+	ushort	     nd_seq_size[SEQ_MAX];   /* Transmit seq packet size   */
+	ulong	     nd_seq_time[SEQ_MAX];   /* Transmit seq packet time   */
+
+	ushort	     nd_hw_ver;		  /* HW version returned from PS   */
+	ushort	     nd_sw_ver;		  /* SW version returned from PS   */
+	uint	     nd_hw_id;		  /* HW ID returned from PS	   */
+	u8	  nd_ps_desc[MAX_DESC_LEN+1];  /* Description from PS	*/
+	uint	     nd_vpd_len;		/* VPD len, if any */
+	u8	     nd_vpd[VPDSIZE];		/* VPD, if any */
+
+	ulong	     nd_ttdriver_flags;	  /* Registration status	    */
+	struct tty_driver *nd_serial_ttdriver;	/* Linux TTYDRIVER structure */
+	struct tty_driver *nd_callout_ttdriver; /* Linux TTYDRIVER structure */
+	struct tty_driver *nd_xprint_ttdriver;	/* Linux TTYDRIVER structure */
+
+	u8	     *nd_writebuf;		/* Used to cache data read
+						 * from user
+						 */
+	struct ch_struct nd_chan[CHAN_MAX];  /* Channel array		    */
+	struct device *nd_class_dev;	/* Hang our sysfs stuff off of here */
+};
+
+#endif /* __DRP_H */