Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next

Pull sparc updates from David Miller:

 1) Use register window state adjustment instructions when available,
    from Anthony Yznaga.

 2) Add VCC console concentrator driver, from Jag Raman.

 3) Add 16GB hugepage support, from Nitin Gupta.

 4) Support cpu 'poke' hypercall, from Vijay Kumar.

 5) Add M7/M8 optimized memcpy/memset/copy_{to,from}_user, from Babu
    Moger.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next: (33 commits)
  sparc64: Handle additional cases of no fault loads
  sparc64: speed up etrap/rtrap on NG2 and later processors
  sparc64: vcc: make ktermios const
  sparc: leon: grpci1: constify of_device_id
  sparc: leon: grpci2: constify of_device_id
  sparc64: vcc: Check for IS_ERR() instead of NULL
  sparc64: Cleanup hugepage table walk functions
  sparc64: Add 16GB hugepage support
  sparc64: Support huge PUD case in get_user_pages
  sparc64: vcc: Add install & cleanup TTY operations
  sparc64: vcc: Add break_ctl TTY operation
  sparc64: vcc: Add chars_in_buffer TTY operation
  sparc64: vcc: Add write & write_room TTY operations
  sparc64: vcc: Add hangup TTY operation
  sparc64: vcc: Add open & close TTY operations
  sparc64: vcc: Enable LDC event processing engine
  sparc64: vcc: Add RX & TX timer for delayed LDC operation
  sparc64: vcc: Create sysfs attribute group
  sparc64: vcc: Enable VCC port probe and removal
  sparc64: vcc: TTY driver initialization and cleanup
  ...

3 files changed, 1161 insertions, 0 deletions

diff --git a/drivers/tty/Kconfig b/drivers/tty/Kconfig
index 873e0ba89737..cc2b4d9433ed 100644
--- a/drivers/tty/Kconfig
+++ b/drivers/tty/Kconfig
@@ -458,4 +458,9 @@ config MIPS_EJTAG_FDC_KGDB_CHAN
 	help
 	  FDC channel number to use for KGDB.
 
+config VCC
+	tristate "Sun Virtual Console Concentrator"
+	depends on SUN_LDOMS
+	help
+	  Support for Sun logical domain consoles.
 endif # TTY
diff --git a/drivers/tty/Makefile b/drivers/tty/Makefile
index 8689279afdf1..16330a819685 100644
--- a/drivers/tty/Makefile
+++ b/drivers/tty/Makefile
@@ -33,5 +33,6 @@ obj-$(CONFIG_PPC_EPAPR_HV_BYTECHAN) += ehv_bytechan.o
 obj-$(CONFIG_GOLDFISH_TTY)	+= goldfish.o
 obj-$(CONFIG_DA_TTY)		+= metag_da.o
 obj-$(CONFIG_MIPS_EJTAG_FDC_TTY) += mips_ejtag_fdc.o
+obj-$(CONFIG_VCC)		+= vcc.o
 
 obj-y += ipwireless/
diff --git a/drivers/tty/vcc.c b/drivers/tty/vcc.c
new file mode 100644
index 000000000000..ef01d24858cd
--- /dev/null
+++ b/drivers/tty/vcc.c
@@ -0,0 +1,1155 @@
+/* vcc.c: sun4v virtual channel concentrator
+ *
+ * Copyright (C) 2017 Oracle. All rights reserved.
+ */
+
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <asm/vio.h>
+#include <asm/ldc.h>
+
+#define DRV_MODULE_NAME		"vcc"
+#define DRV_MODULE_VERSION	"1.1"
+#define DRV_MODULE_RELDATE	"July 1, 2017"
+
+static char version[] =
+	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")";
+
+MODULE_DESCRIPTION("Sun LDOM virtual console concentrator driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_MODULE_VERSION);
+
+struct vcc_port {
+	struct vio_driver_state vio;
+
+	spinlock_t lock;
+	char *domain;
+	struct tty_struct *tty;	/* only populated while dev is open */
+	unsigned long index;	/* index into the vcc_table */
+
+	u64 refcnt;
+	bool excl_locked;
+
+	bool removed;
+
+	/* This buffer is required to support the tty write_room interface
+	 * and guarantee that any characters that the driver accepts will
+	 * be eventually sent, either immediately or later.
+	 */
+	int chars_in_buffer;
+	struct vio_vcc buffer;
+
+	struct timer_list rx_timer;
+	struct timer_list tx_timer;
+};
+
+/* Microseconds that thread will delay waiting for a vcc port ref */
+#define VCC_REF_DELAY		100
+
+#define VCC_MAX_PORTS		1024
+#define VCC_MINOR_START		0	/* must be zero */
+#define VCC_BUFF_LEN		VIO_VCC_MTU_SIZE
+
+#define VCC_CTL_BREAK		-1
+#define VCC_CTL_HUP		-2
+
+static const char vcc_driver_name[] = "vcc";
+static const char vcc_device_node[] = "vcc";
+static struct tty_driver *vcc_tty_driver;
+
+static struct vcc_port *vcc_table[VCC_MAX_PORTS];
+static DEFINE_SPINLOCK(vcc_table_lock);
+
+int vcc_dbg;
+int vcc_dbg_ldc;
+int vcc_dbg_vio;
+
+module_param(vcc_dbg, uint, 0664);
+module_param(vcc_dbg_ldc, uint, 0664);
+module_param(vcc_dbg_vio, uint, 0664);
+
+#define VCC_DBG_DRV	0x1
+#define VCC_DBG_LDC	0x2
+#define VCC_DBG_PKT	0x4
+
+#define vccdbg(f, a...)						\
+	do {							\
+		if (vcc_dbg & VCC_DBG_DRV)			\
+			pr_info(f, ## a);			\
+	} while (0)						\
+
+#define vccdbgl(l)						\
+	do {							\
+		if (vcc_dbg & VCC_DBG_LDC)			\
+			ldc_print(l);				\
+	} while (0)						\
+
+#define vccdbgp(pkt)						\
+	do {							\
+		if (vcc_dbg & VCC_DBG_PKT) {			\
+			int i;					\
+			for (i = 0; i < pkt.tag.stype; i++)	\
+				pr_info("[%c]", pkt.data[i]);	\
+		}						\
+	} while (0)						\
+
+/* Note: Be careful when adding flags to this line discipline.  Don't
+ * add anything that will cause echoing or we'll go into recursive
+ * loop echoing chars back and forth with the console drivers.
+ */
+static const struct ktermios vcc_tty_termios = {
+	.c_iflag = IGNBRK | IGNPAR,
+	.c_oflag = OPOST,
+	.c_cflag = B38400 | CS8 | CREAD | HUPCL,
+	.c_cc = INIT_C_CC,
+	.c_ispeed = 38400,
+	.c_ospeed = 38400
+};
+
+/**
+ * vcc_table_add() - Add VCC port to the VCC table
+ * @port: pointer to the VCC port
+ *
+ * Return: index of the port in the VCC table on success,
+ *	   -1 on failure
+ */
+static int vcc_table_add(struct vcc_port *port)
+{
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&vcc_table_lock, flags);
+	for (i = VCC_MINOR_START; i < VCC_MAX_PORTS; i++) {
+		if (!vcc_table[i]) {
+			vcc_table[i] = port;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&vcc_table_lock, flags);
+
+	if (i < VCC_MAX_PORTS)
+		return i;
+	else
+		return -1;
+}
+
+/**
+ * vcc_table_remove() - Removes a VCC port from the VCC table
+ * @index: Index into the VCC table
+ */
+static void vcc_table_remove(unsigned long index)
+{
+	unsigned long flags;
+
+	if (WARN_ON(index >= VCC_MAX_PORTS))
+		return;
+
+	spin_lock_irqsave(&vcc_table_lock, flags);
+	vcc_table[index] = NULL;
+	spin_unlock_irqrestore(&vcc_table_lock, flags);
+}
+
+/**
+ * vcc_get() - Gets a reference to VCC port
+ * @index: Index into the VCC table
+ * @excl: Indicates if an exclusive access is requested
+ *
+ * Return: reference to the VCC port, if found
+ *	   NULL, if port not found
+ */
+static struct vcc_port *vcc_get(unsigned long index, bool excl)
+{
+	struct vcc_port *port;
+	unsigned long flags;
+
+try_again:
+	spin_lock_irqsave(&vcc_table_lock, flags);
+
+	port = vcc_table[index];
+	if (!port) {
+		spin_unlock_irqrestore(&vcc_table_lock, flags);
+		return NULL;
+	}
+
+	if (!excl) {
+		if (port->excl_locked) {
+			spin_unlock_irqrestore(&vcc_table_lock, flags);
+			udelay(VCC_REF_DELAY);
+			goto try_again;
+		}
+		port->refcnt++;
+		spin_unlock_irqrestore(&vcc_table_lock, flags);
+		return port;
+	}
+
+	if (port->refcnt) {
+		spin_unlock_irqrestore(&vcc_table_lock, flags);
+		/* Threads wanting exclusive access will wait half the time,
+		 * probably giving them higher priority in the case of
+		 * multiple waiters.
+		 */
+		udelay(VCC_REF_DELAY/2);
+		goto try_again;
+	}
+
+	port->refcnt++;
+	port->excl_locked = true;
+	spin_unlock_irqrestore(&vcc_table_lock, flags);
+
+	return port;
+}
+
+/**
+ * vcc_put() - Returns a reference to VCC port
+ * @port: pointer to VCC port
+ * @excl: Indicates if the returned reference is an exclusive reference
+ *
+ * Note: It's the caller's responsibility to ensure the correct value
+ *	 for the excl flag
+ */
+static void vcc_put(struct vcc_port *port, bool excl)
+{
+	unsigned long flags;
+
+	if (!port)
+		return;
+
+	spin_lock_irqsave(&vcc_table_lock, flags);
+
+	/* check if caller attempted to put with the wrong flags */
+	if (WARN_ON((excl && !port->excl_locked) ||
+		    (!excl && port->excl_locked)))
+		goto done;
+
+	port->refcnt--;
+
+	if (excl)
+		port->excl_locked = false;
+
+done:
+	spin_unlock_irqrestore(&vcc_table_lock, flags);
+}
+
+/**
+ * vcc_get_ne() - Get a non-exclusive reference to VCC port
+ * @index: Index into the VCC table
+ *
+ * Gets a non-exclusive reference to VCC port, if it's not removed
+ *
+ * Return: pointer to the VCC port, if found
+ *	   NULL, if port not found
+ */
+static struct vcc_port *vcc_get_ne(unsigned long index)
+{
+	struct vcc_port *port;
+
+	port = vcc_get(index, false);
+
+	if (port && port->removed) {
+		vcc_put(port, false);
+		return NULL;
+	}
+
+	return port;
+}
+
+static void vcc_kick_rx(struct vcc_port *port)
+{
+	struct vio_driver_state *vio = &port->vio;
+
+	assert_spin_locked(&port->lock);
+
+	if (!timer_pending(&port->rx_timer) && !port->removed) {
+		disable_irq_nosync(vio->vdev->rx_irq);
+		port->rx_timer.expires = (jiffies + 1);
+		add_timer(&port->rx_timer);
+	}
+}
+
+static void vcc_kick_tx(struct vcc_port *port)
+{
+	assert_spin_locked(&port->lock);
+
+	if (!timer_pending(&port->tx_timer) && !port->removed) {
+		port->tx_timer.expires = (jiffies + 1);
+		add_timer(&port->tx_timer);
+	}
+}
+
+static int vcc_rx_check(struct tty_struct *tty, int size)
+{
+	if (WARN_ON(!tty || !tty->port))
+		return 1;
+
+	/* tty_buffer_request_room won't sleep because it uses
+	 * GFP_ATOMIC flag to allocate buffer
+	 */
+	if (test_bit(TTY_THROTTLED, &tty->flags) ||
+	    (tty_buffer_request_room(tty->port, VCC_BUFF_LEN) < VCC_BUFF_LEN))
+		return 0;
+
+	return 1;
+}
+
+static int vcc_rx(struct tty_struct *tty, char *buf, int size)
+{
+	int len = 0;
+
+	if (WARN_ON(!tty || !tty->port))
+		return len;
+
+	len = tty_insert_flip_string(tty->port, buf, size);
+	if (len)
+		tty_flip_buffer_push(tty->port);
+
+	return len;
+}
+
+static int vcc_ldc_read(struct vcc_port *port)
+{
+	struct vio_driver_state *vio = &port->vio;
+	struct tty_struct *tty;
+	struct vio_vcc pkt;
+	int rv = 0;
+
+	tty = port->tty;
+	if (!tty) {
+		rv = ldc_rx_reset(vio->lp);
+		vccdbg("VCC: reset rx q: rv=%d\n", rv);
+		goto done;
+	}
+
+	/* Read as long as LDC has incoming data. */
+	while (1) {
+		if (!vcc_rx_check(tty, VIO_VCC_MTU_SIZE)) {
+			vcc_kick_rx(port);
+			break;
+		}
+
+		vccdbgl(vio->lp);
+
+		rv = ldc_read(vio->lp, &pkt, sizeof(pkt));
+		if (rv <= 0)
+			break;
+
+		vccdbg("VCC: ldc_read()=%d\n", rv);
+		vccdbg("TAG [%02x:%02x:%04x:%08x]\n",
+		       pkt.tag.type, pkt.tag.stype,
+		       pkt.tag.stype_env, pkt.tag.sid);
+
+		if (pkt.tag.type == VIO_TYPE_DATA) {
+			vccdbgp(pkt);
+			/* vcc_rx_check ensures memory availability */
+			vcc_rx(tty, pkt.data, pkt.tag.stype);
+		} else {
+			pr_err("VCC: unknown msg [%02x:%02x:%04x:%08x]\n",
+			       pkt.tag.type, pkt.tag.stype,
+			       pkt.tag.stype_env, pkt.tag.sid);
+			rv = -ECONNRESET;
+			break;
+		}
+
+		WARN_ON(rv != LDC_PACKET_SIZE);
+	}
+
+done:
+	return rv;
+}
+
+static void vcc_rx_timer(unsigned long index)
+{
+	struct vio_driver_state *vio;
+	struct vcc_port *port;
+	unsigned long flags;
+	int rv;
+
+	port = vcc_get_ne(index);
+	if (!port)
+		return;
+
+	spin_lock_irqsave(&port->lock, flags);
+	port->rx_timer.expires = 0;
+
+	vio = &port->vio;
+
+	enable_irq(vio->vdev->rx_irq);
+
+	if (!port->tty || port->removed)
+		goto done;
+
+	rv = vcc_ldc_read(port);
+	if (rv == -ECONNRESET)
+		vio_conn_reset(vio);
+
+done:
+	spin_unlock_irqrestore(&port->lock, flags);
+	vcc_put(port, false);
+}
+
+static void vcc_tx_timer(unsigned long index)
+{
+	struct vcc_port *port;
+	struct vio_vcc *pkt;
+	unsigned long flags;
+	int tosend = 0;
+	int rv;
+
+	port = vcc_get_ne(index);
+	if (!port)
+		return;
+
+	spin_lock_irqsave(&port->lock, flags);
+	port->tx_timer.expires = 0;
+
+	if (!port->tty || port->removed)
+		goto done;
+
+	tosend = min(VCC_BUFF_LEN, port->chars_in_buffer);
+	if (!tosend)
+		goto done;
+
+	pkt = &port->buffer;
+	pkt->tag.type = VIO_TYPE_DATA;
+	pkt->tag.stype = tosend;
+	vccdbgl(port->vio.lp);
+
+	rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
+	WARN_ON(!rv);
+
+	if (rv < 0) {
+		vccdbg("VCC: ldc_write()=%d\n", rv);
+		vcc_kick_tx(port);
+	} else {
+		struct tty_struct *tty = port->tty;
+
+		port->chars_in_buffer = 0;
+		if (tty)
+			tty_wakeup(tty);
+	}
+
+done:
+	spin_unlock_irqrestore(&port->lock, flags);
+	vcc_put(port, false);
+}
+
+/**
+ * vcc_event() - LDC event processing engine
+ * @arg: VCC private data
+ * @event: LDC event
+ *
+ * Handles LDC events for VCC
+ */
+static void vcc_event(void *arg, int event)
+{
+	struct vio_driver_state *vio;
+	struct vcc_port *port;
+	unsigned long flags;
+	int rv;
+
+	port = arg;
+	vio = &port->vio;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	switch (event) {
+	case LDC_EVENT_RESET:
+	case LDC_EVENT_UP:
+		vio_link_state_change(vio, event);
+		break;
+
+	case LDC_EVENT_DATA_READY:
+		rv = vcc_ldc_read(port);
+		if (rv == -ECONNRESET)
+			vio_conn_reset(vio);
+		break;
+
+	default:
+		pr_err("VCC: unexpected LDC event(%d)\n", event);
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static struct ldc_channel_config vcc_ldc_cfg = {
+	.event		= vcc_event,
+	.mtu		= VIO_VCC_MTU_SIZE,
+	.mode		= LDC_MODE_RAW,
+	.debug		= 0,
+};
+
+/* Ordered from largest major to lowest */
+static struct vio_version vcc_versions[] = {
+	{ .major = 1, .minor = 0 },
+};
+
+static struct tty_port_operations vcc_port_ops = { 0 };
+
+static ssize_t vcc_sysfs_domain_show(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct vcc_port *port;
+	int rv;
+
+	port = dev_get_drvdata(dev);
+	if (!port)
+		return -ENODEV;
+
+	rv = scnprintf(buf, PAGE_SIZE, "%s\n", port->domain);
+
+	return rv;
+}
+
+static int vcc_send_ctl(struct vcc_port *port, int ctl)
+{
+	struct vio_vcc pkt;
+	int rv;
+
+	pkt.tag.type = VIO_TYPE_CTRL;
+	pkt.tag.sid = ctl;
+	pkt.tag.stype = 0;
+
+	rv = ldc_write(port->vio.lp, &pkt, sizeof(pkt.tag));
+	WARN_ON(!rv);
+	vccdbg("VCC: ldc_write(%ld)=%d\n", sizeof(pkt.tag), rv);
+
+	return rv;
+}
+
+static ssize_t vcc_sysfs_break_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct vcc_port *port;
+	unsigned long flags;
+	int rv = count;
+	int brk;
+
+	port = dev_get_drvdata(dev);
+	if (!port)
+		return -ENODEV;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	if (sscanf(buf, "%ud", &brk) != 1 || brk != 1)
+		rv = -EINVAL;
+	else if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
+		vcc_kick_tx(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	return rv;
+}
+
+static DEVICE_ATTR(domain, 0400, vcc_sysfs_domain_show, NULL);
+static DEVICE_ATTR(break, 0200, NULL, vcc_sysfs_break_store);
+
+static struct attribute *vcc_sysfs_entries[] = {
+	&dev_attr_domain.attr,
+	&dev_attr_break.attr,
+	NULL
+};
+
+static struct attribute_group vcc_attribute_group = {
+	.name = NULL,
+	.attrs = vcc_sysfs_entries,
+};
+
+/**
+ * vcc_probe() - Initialize VCC port
+ * @vdev: Pointer to VIO device of the new VCC port
+ * @id: VIO device ID
+ *
+ * Initializes a VCC port to receive serial console data from
+ * the guest domain. Sets up a TTY end point on the control
+ * domain. Sets up VIO/LDC link between the guest & control
+ * domain endpoints.
+ *
+ * Return: status of the probe
+ */
+static int vcc_probe(struct vio_dev *vdev, const struct vio_device_id *id)
+{
+	struct mdesc_handle *hp;
+	struct vcc_port *port;
+	struct device *dev;
+	const char *domain;
+	char *name;
+	u64 node;
+	int rv;
+
+	vccdbg("VCC: name=%s\n", dev_name(&vdev->dev));
+
+	if (!vcc_tty_driver) {
+		pr_err("VCC: TTY driver not registered\n");
+		return -ENODEV;
+	}
+
+	port = kzalloc(sizeof(struct vcc_port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	name = kstrdup(dev_name(&vdev->dev), GFP_KERNEL);
+
+	rv = vio_driver_init(&port->vio, vdev, VDEV_CONSOLE_CON, vcc_versions,
+			     ARRAY_SIZE(vcc_versions), NULL, name);
+	if (rv)
+		goto free_port;
+
+	port->vio.debug = vcc_dbg_vio;
+	vcc_ldc_cfg.debug = vcc_dbg_ldc;
+
+	rv = vio_ldc_alloc(&port->vio, &vcc_ldc_cfg, port);
+	if (rv)
+		goto free_port;
+
+	spin_lock_init(&port->lock);
+
+	port->index = vcc_table_add(port);
+	if (port->index == -1) {
+		pr_err("VCC: no more TTY indices left for allocation\n");
+		goto free_ldc;
+	}
+
+	/* Register the device using VCC table index as TTY index */
+	dev = tty_register_device(vcc_tty_driver, port->index, &vdev->dev);
+	if (IS_ERR(dev)) {
+		rv = PTR_ERR(dev);
+		goto free_table;
+	}
+
+	hp = mdesc_grab();
+
+	node = vio_vdev_node(hp, vdev);
+	if (node == MDESC_NODE_NULL) {
+		rv = -ENXIO;
+		mdesc_release(hp);
+		goto unreg_tty;
+	}
+
+	domain = mdesc_get_property(hp, node, "vcc-domain-name", NULL);
+	if (!domain) {
+		rv = -ENXIO;
+		mdesc_release(hp);
+		goto unreg_tty;
+	}
+	port->domain = kstrdup(domain, GFP_KERNEL);
+
+	mdesc_release(hp);
+
+	rv = sysfs_create_group(&vdev->dev.kobj, &vcc_attribute_group);
+	if (rv)
+		goto free_domain;
+
+	init_timer(&port->rx_timer);
+	port->rx_timer.function = vcc_rx_timer;
+	port->rx_timer.data = port->index;
+
+	init_timer(&port->tx_timer);
+	port->tx_timer.function = vcc_tx_timer;
+	port->tx_timer.data = port->index;
+
+	dev_set_drvdata(&vdev->dev, port);
+
+	/* It's possible to receive IRQs in the middle of vio_port_up. Disable
+	 * IRQs until the port is up.
+	 */
+	disable_irq_nosync(vdev->rx_irq);
+	vio_port_up(&port->vio);
+	enable_irq(vdev->rx_irq);
+
+	return 0;
+
+free_domain:
+	kfree(port->domain);
+unreg_tty:
+	tty_unregister_device(vcc_tty_driver, port->index);
+free_table:
+	vcc_table_remove(port->index);
+free_ldc:
+	vio_ldc_free(&port->vio);
+free_port:
+	kfree(name);
+	kfree(port);
+
+	return rv;
+}
+
+/**
+ * vcc_remove() - Terminate a VCC port
+ * @vdev: Pointer to VIO device of the VCC port
+ *
+ * Terminates a VCC port. Sets up the teardown of TTY and
+ * VIO/LDC link between guest and primary domains.
+ *
+ * Return: status of removal
+ */
+static int vcc_remove(struct vio_dev *vdev)
+{
+	struct vcc_port *port = dev_get_drvdata(&vdev->dev);
+
+	if (!port)
+		return -ENODEV;
+
+	del_timer_sync(&port->rx_timer);
+	del_timer_sync(&port->tx_timer);
+
+	/* If there's a process with the device open, do a synchronous
+	 * hangup of the TTY. This *may* cause the process to call close
+	 * asynchronously, but it's not guaranteed.
+	 */
+	if (port->tty)
+		tty_vhangup(port->tty);
+
+	/* Get exclusive reference to VCC, ensures that there are no other
+	 * clients to this port
+	 */
+	port = vcc_get(port->index, true);
+
+	if (WARN_ON(!port))
+		return -ENODEV;
+
+	tty_unregister_device(vcc_tty_driver, port->index);
+
+	del_timer_sync(&port->vio.timer);
+	vio_ldc_free(&port->vio);
+	sysfs_remove_group(&vdev->dev.kobj, &vcc_attribute_group);
+	dev_set_drvdata(&vdev->dev, NULL);
+	if (port->tty) {
+		port->removed = true;
+		vcc_put(port, true);
+	} else {
+		vcc_table_remove(port->index);
+
+		kfree(port->vio.name);
+		kfree(port->domain);
+		kfree(port);
+	}
+
+	return 0;
+}
+
+static const struct vio_device_id vcc_match[] = {
+	{
+		.type = "vcc-port",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(vio, vcc_match);
+
+static struct vio_driver vcc_driver = {
+	.id_table	= vcc_match,
+	.probe		= vcc_probe,
+	.remove		= vcc_remove,
+	.name		= "vcc",
+};
+
+static int vcc_open(struct tty_struct *tty, struct file *vcc_file)
+{
+	struct vcc_port *port;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: open: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	if (tty->count > 1)
+		return -EBUSY;
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: open: Failed to find VCC port\n");
+		return -ENODEV;
+	}
+
+	if (unlikely(!port->vio.lp)) {
+		pr_err("VCC: open: LDC channel not configured\n");
+		vcc_put(port, false);
+		return -EPIPE;
+	}
+	vccdbgl(port->vio.lp);
+
+	vcc_put(port, false);
+
+	if (unlikely(!tty->port)) {
+		pr_err("VCC: open: TTY port not found\n");
+		return -ENXIO;
+	}
+
+	if (unlikely(!tty->port->ops)) {
+		pr_err("VCC: open: TTY ops not defined\n");
+		return -ENXIO;
+	}
+
+	return tty_port_open(tty->port, tty, vcc_file);
+}
+
+static void vcc_close(struct tty_struct *tty, struct file *vcc_file)
+{
+	if (unlikely(!tty)) {
+		pr_err("VCC: close: Invalid TTY handle\n");
+		return;
+	}
+
+	if (unlikely(tty->count > 1))
+		return;
+
+	if (unlikely(!tty->port)) {
+		pr_err("VCC: close: TTY port not found\n");
+		return;
+	}
+
+	tty_port_close(tty->port, tty, vcc_file);
+}
+
+static void vcc_ldc_hup(struct vcc_port *port)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	if (vcc_send_ctl(port, VCC_CTL_HUP) < 0)
+		vcc_kick_tx(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+}
+
+static void vcc_hangup(struct tty_struct *tty)
+{
+	struct vcc_port *port;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: hangup: Invalid TTY handle\n");
+		return;
+	}
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: hangup: Failed to find VCC port\n");
+		return;
+	}
+
+	if (unlikely(!tty->port)) {
+		pr_err("VCC: hangup: TTY port not found\n");
+		vcc_put(port, false);
+		return;
+	}
+
+	vcc_ldc_hup(port);
+
+	vcc_put(port, false);
+
+	tty_port_hangup(tty->port);
+}
+
+static int vcc_write(struct tty_struct *tty, const unsigned char *buf,
+		     int count)
+{
+	struct vcc_port *port;
+	struct vio_vcc *pkt;
+	unsigned long flags;
+	int total_sent = 0;
+	int tosend = 0;
+	int rv = -EINVAL;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: write: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: write: Failed to find VCC port");
+		return -ENODEV;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	pkt = &port->buffer;
+	pkt->tag.type = VIO_TYPE_DATA;
+
+	while (count > 0) {
+		/* Minimum of data to write and space available */
+		tosend = min(count, (VCC_BUFF_LEN - port->chars_in_buffer));
+
+		if (!tosend)
+			break;
+
+		memcpy(&pkt->data[port->chars_in_buffer], &buf[total_sent],
+		       tosend);
+		port->chars_in_buffer += tosend;
+		pkt->tag.stype = tosend;
+
+		vccdbg("TAG [%02x:%02x:%04x:%08x]\n", pkt->tag.type,
+		       pkt->tag.stype, pkt->tag.stype_env, pkt->tag.sid);
+		vccdbg("DATA [%s]\n", pkt->data);
+		vccdbgl(port->vio.lp);
+
+		/* Since we know we have enough room in VCC buffer for tosend
+		 * we record that it was sent regardless of whether the
+		 * hypervisor actually took it because we have it buffered.
+		 */
+		rv = ldc_write(port->vio.lp, pkt, (VIO_TAG_SIZE + tosend));
+		vccdbg("VCC: write: ldc_write(%d)=%d\n",
+		       (VIO_TAG_SIZE + tosend), rv);
+
+		total_sent += tosend;
+		count -= tosend;
+		if (rv < 0) {
+			vcc_kick_tx(port);
+			break;
+		}
+
+		port->chars_in_buffer = 0;
+	}
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	vcc_put(port, false);
+
+	vccdbg("VCC: write: total=%d rv=%d", total_sent, rv);
+
+	return total_sent ? total_sent : rv;
+}
+
+static int vcc_write_room(struct tty_struct *tty)
+{
+	struct vcc_port *port;
+	u64 num;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: write_room: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: write_room: Failed to find VCC port\n");
+		return -ENODEV;
+	}
+
+	num = VCC_BUFF_LEN - port->chars_in_buffer;
+
+	vcc_put(port, false);
+
+	return num;
+}
+
+static int vcc_chars_in_buffer(struct tty_struct *tty)
+{
+	struct vcc_port *port;
+	u64 num;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: chars_in_buffer: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: chars_in_buffer: Failed to find VCC port\n");
+		return -ENODEV;
+	}
+
+	num = port->chars_in_buffer;
+
+	vcc_put(port, false);
+
+	return num;
+}
+
+static int vcc_break_ctl(struct tty_struct *tty, int state)
+{
+	struct vcc_port *port;
+	unsigned long flags;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: break_ctl: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	port = vcc_get_ne(tty->index);
+	if (unlikely(!port)) {
+		pr_err("VCC: break_ctl: Failed to find VCC port\n");
+		return -ENODEV;
+	}
+
+	/* Turn off break */
+	if (state == 0) {
+		vcc_put(port, false);
+		return 0;
+	}
+
+	spin_lock_irqsave(&port->lock, flags);
+
+	if (vcc_send_ctl(port, VCC_CTL_BREAK) < 0)
+		vcc_kick_tx(port);
+
+	spin_unlock_irqrestore(&port->lock, flags);
+
+	vcc_put(port, false);
+
+	return 0;
+}
+
+static int vcc_install(struct tty_driver *driver, struct tty_struct *tty)
+{
+	struct vcc_port *port_vcc;
+	struct tty_port *port_tty;
+	int ret;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: install: Invalid TTY handle\n");
+		return -ENXIO;
+	}
+
+	if (tty->index >= VCC_MAX_PORTS)
+		return -EINVAL;
+
+	ret = tty_standard_install(driver, tty);
+	if (ret)
+		return ret;
+
+	port_tty = kzalloc(sizeof(struct tty_port), GFP_KERNEL);
+	if (!port_tty)
+		return -ENOMEM;
+
+	port_vcc = vcc_get(tty->index, true);
+	if (!port_vcc) {
+		pr_err("VCC: install: Failed to find VCC port\n");
+		tty->port = NULL;
+		kfree(port_tty);
+		return -ENODEV;
+	}
+
+	tty_port_init(port_tty);
+	port_tty->ops = &vcc_port_ops;
+	tty->port = port_tty;
+
+	port_vcc->tty = tty;
+
+	vcc_put(port_vcc, true);
+
+	return 0;
+}
+
+static void vcc_cleanup(struct tty_struct *tty)
+{
+	struct vcc_port *port;
+
+	if (unlikely(!tty)) {
+		pr_err("VCC: cleanup: Invalid TTY handle\n");
+		return;
+	}
+
+	port = vcc_get(tty->index, true);
+	if (port) {
+		port->tty = NULL;
+
+		if (port->removed) {
+			vcc_table_remove(tty->index);
+			kfree(port->vio.name);
+			kfree(port->domain);
+			kfree(port);
+		} else {
+			vcc_put(port, true);
+		}
+	}
+
+	tty_port_destroy(tty->port);
+	kfree(tty->port);
+	tty->port = NULL;
+}
+
+static const struct tty_operations vcc_ops = {
+	.open			= vcc_open,
+	.close			= vcc_close,
+	.hangup			= vcc_hangup,
+	.write			= vcc_write,
+	.write_room		= vcc_write_room,
+	.chars_in_buffer	= vcc_chars_in_buffer,
+	.break_ctl		= vcc_break_ctl,
+	.install		= vcc_install,
+	.cleanup		= vcc_cleanup,
+};
+
+#define VCC_TTY_FLAGS   (TTY_DRIVER_DYNAMIC_DEV | TTY_DRIVER_REAL_RAW)
+
+static int vcc_tty_init(void)
+{
+	int rv;
+
+	pr_info("VCC: %s\n", version);
+
+	vcc_tty_driver = tty_alloc_driver(VCC_MAX_PORTS, VCC_TTY_FLAGS);
+	if (IS_ERR(vcc_tty_driver)) {
+		pr_err("VCC: TTY driver alloc failed\n");
+		return PTR_ERR(vcc_tty_driver);
+	}
+
+	vcc_tty_driver->driver_name = vcc_driver_name;
+	vcc_tty_driver->name = vcc_device_node;
+
+	vcc_tty_driver->minor_start = VCC_MINOR_START;
+	vcc_tty_driver->type = TTY_DRIVER_TYPE_SYSTEM;
+	vcc_tty_driver->init_termios = vcc_tty_termios;
+
+	tty_set_operations(vcc_tty_driver, &vcc_ops);
+
+	rv = tty_register_driver(vcc_tty_driver);
+	if (rv) {
+		pr_err("VCC: TTY driver registration failed\n");
+		put_tty_driver(vcc_tty_driver);
+		vcc_tty_driver = NULL;
+		return rv;
+	}
+
+	vccdbg("VCC: TTY driver registered\n");
+
+	return 0;
+}
+
+static void vcc_tty_exit(void)
+{
+	tty_unregister_driver(vcc_tty_driver);
+	put_tty_driver(vcc_tty_driver);
+	vccdbg("VCC: TTY driver unregistered\n");
+
+	vcc_tty_driver = NULL;
+}
+
+static int __init vcc_init(void)
+{
+	int rv;
+
+	rv = vcc_tty_init();
+	if (rv) {
+		pr_err("VCC: TTY init failed\n");
+		return rv;
+	}
+
+	rv = vio_register_driver(&vcc_driver);
+	if (rv) {
+		pr_err("VCC: VIO driver registration failed\n");
+		vcc_tty_exit();
+	} else {
+		vccdbg("VCC: VIO driver registered successfully\n");
+	}
+
+	return rv;
+}
+
+static void __exit vcc_exit(void)
+{
+	vio_unregister_driver(&vcc_driver);
+	vccdbg("VCC: VIO driver unregistered\n");
+	vcc_tty_exit();
+	vccdbg("VCC: TTY driver unregistered\n");
+}
+
+module_init(vcc_init);
+module_exit(vcc_exit);