[MIPS] kpsd and other AP/SP improvements.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 362 insertions, 155 deletions

diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 986a9cf23067..6179805af9f0 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -21,45 +21,44 @@
 #include <linux/module.h>
 #include <linux/fs.h>
 #include <linux/init.h>
+#include <asm/uaccess.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/vmalloc.h>
+#include <linux/elf.h>
+#include <linux/seq_file.h>
+#include <linux/syscalls.h>
+#include <linux/moduleloader.h>
 #include <linux/interrupt.h>
-#include <linux/irq.h>
 #include <linux/poll.h>
 #include <linux/sched.h>
 #include <linux/wait.h>
-
 #include <asm/mipsmtregs.h>
-#include <asm/bitops.h>
+#include <asm/cacheflush.h>
+#include <asm/atomic.h>
 #include <asm/cpu.h>
 #include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/vpe.h>
 #include <asm/rtlx.h>
-#include <asm/uaccess.h>
 
 #define RTLX_TARG_VPE 1
 
 static struct rtlx_info *rtlx;
 static int major;
 static char module_name[] = "rtlx";
-static struct irqaction irq;
-static int irq_num;
-
-static inline int spacefree(int read, int write, int size)
-{
-	if (read == write) {
-		/*
-		 * never fill the buffer completely, so indexes are always
-		 * equal if empty and only empty, or !equal if data available
-		 */
-		return size - 1;
-	}
-
-	return ((read + size - write) % size) - 1;
-}
 
 static struct chan_waitqueues {
 	wait_queue_head_t rt_queue;
 	wait_queue_head_t lx_queue;
+	int in_open;
 } channel_wqs[RTLX_CHANNELS];
 
+static struct irqaction irq;
+static int irq_num;
+static struct vpe_notifications notify;
+static int sp_stopping = 0;
+
 extern void *vpe_get_shared(int index);
 
 static void rtlx_dispatch(struct pt_regs *regs)
@@ -67,174 +66,298 @@ static void rtlx_dispatch(struct pt_regs *regs)
 	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
 }
 
+
+/* Interrupt handler may be called before rtlx_init has otherwise had
+   a chance to run.
+*/
 static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 {
 	int i;
 
 	for (i = 0; i < RTLX_CHANNELS; i++) {
-		struct rtlx_channel *chan = &rtlx->channel[i];
-
-		if (chan->lx_read != chan->lx_write)
-			wake_up_interruptible(&channel_wqs[i].lx_queue);
+			wake_up(&channel_wqs[i].lx_queue);
+			wake_up(&channel_wqs[i].rt_queue);
 	}
 
 	return IRQ_HANDLED;
 }
 
-/* call when we have the address of the shared structure from the SP side. */
-static int rtlx_init(struct rtlx_info *rtlxi)
+static __attribute_used__ void dump_rtlx(void)
 {
 	int i;
 
-	if (rtlxi->id != RTLX_ID) {
-		printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
-		return -ENOEXEC;
-	}
+	printk("id 0x%lx state %d\n", rtlx->id, rtlx->state);
 
-	/* initialise the wait queues */
 	for (i = 0; i < RTLX_CHANNELS; i++) {
-		init_waitqueue_head(&channel_wqs[i].rt_queue);
-		init_waitqueue_head(&channel_wqs[i].lx_queue);
-	}
+		struct rtlx_channel *chan = &rtlx->channel[i];
 
-	/* set up for interrupt handling */
-	memset(&irq, 0, sizeof(struct irqaction));
+		printk(" rt_state %d lx_state %d buffer_size %d\n",
+		       chan->rt_state, chan->lx_state, chan->buffer_size);
 
-	if (cpu_has_vint)
-		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
+		printk(" rt_read %d rt_write %d\n",
+		       chan->rt_read, chan->rt_write);
 
-	irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
-	irq.handler = rtlx_interrupt;
-	irq.flags = SA_INTERRUPT;
-	irq.name = "RTLX";
-	irq.dev_id = rtlx;
-	setup_irq(irq_num, &irq);
+		printk(" lx_read %d lx_write %d\n",
+		       chan->lx_read, chan->lx_write);
+
+		printk(" rt_buffer <%s>\n", chan->rt_buffer);
+		printk(" lx_buffer <%s>\n", chan->lx_buffer);
+	}
+}
+
+/* call when we have the address of the shared structure from the SP side. */
+static int rtlx_init(struct rtlx_info *rtlxi)
+{
+	if (rtlxi->id != RTLX_ID) {
+		printk(KERN_ERR "no valid RTLX id at 0x%p 0x%x\n", rtlxi, rtlxi->id);
+		return -ENOEXEC;
+	}
 
 	rtlx = rtlxi;
 
 	return 0;
 }
 
-/* only allow one open process at a time to open each channel */
-static int rtlx_open(struct inode *inode, struct file *filp)
+/* notifications */
+static void starting(int vpe)
 {
-	int minor, ret;
+	int i;
+	sp_stopping = 0;
+
+	/* force a reload of rtlx */
+	rtlx=NULL;
+
+	/* wake up any sleeping rtlx_open's */
+	for (i = 0; i < RTLX_CHANNELS; i++)
+		wake_up_interruptible(&channel_wqs[i].lx_queue);
+}
+
+static void stopping(int vpe)
+{
+	int i;
+
+	sp_stopping = 1;
+	for (i = 0; i < RTLX_CHANNELS; i++)
+		wake_up_interruptible(&channel_wqs[i].lx_queue);
+}
+
+
+int rtlx_open(int index, int can_sleep)
+{
+	int ret;
 	struct rtlx_channel *chan;
+	volatile struct rtlx_info **p;
 
-	/* assume only 1 device at the mo. */
-	minor = MINOR(inode->i_rdev);
+	if (index >= RTLX_CHANNELS) {
+		printk(KERN_DEBUG "rtlx_open index out of range\n");
+		return -ENOSYS;
+	}
+
+	if (channel_wqs[index].in_open) {
+		printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
+		return -EBUSY;
+	}
+
+	channel_wqs[index].in_open++;
 
 	if (rtlx == NULL) {
-		struct rtlx_info **p;
 		if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
-			printk(KERN_ERR "vpe_get_shared is NULL. "
-			       "Has an SP program been loaded?\n");
-			return -EFAULT;
+			if (can_sleep) {
+				DECLARE_WAITQUEUE(wait, current);
+
+				/* go to sleep */
+				add_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+				set_current_state(TASK_INTERRUPTIBLE);
+				while ((p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
+					schedule();
+					set_current_state(TASK_INTERRUPTIBLE);
+				}
+
+				set_current_state(TASK_RUNNING);
+				remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+				/* back running */
+			} else {
+				printk( KERN_DEBUG "No SP program loaded, and device "
+					"opened with O_NONBLOCK\n");
+				channel_wqs[index].in_open = 0;
+				return -ENOSYS;
+			}
 		}
 
 		if (*p == NULL) {
-			printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
-			return -EFAULT;
+			if (can_sleep) {
+				DECLARE_WAITQUEUE(wait, current);
+
+				/* go to sleep */
+				add_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+				set_current_state(TASK_INTERRUPTIBLE);
+				while (*p == NULL) {
+					schedule();
+
+					/* reset task state to interruptable otherwise
+					   we'll whizz round here like a very fast loopy
+					   thing. schedule() appears to return with state
+					   set to TASK_RUNNING.
+
+					   If the loaded SP program, for whatever reason,
+					   doesn't set up the shared structure *p will never
+					   become true. So whoever connected to either /dev/rt?
+					   or if it was kspd, will then take up rather a lot of
+					   processor cycles.
+					*/
+
+					set_current_state(TASK_INTERRUPTIBLE);
+				}
+
+				set_current_state(TASK_RUNNING);
+				remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+				/* back running */
+			}
+			else {
+				printk(" *vpe_get_shared is NULL. "
+				       "Has an SP program been loaded?\n");
+				channel_wqs[index].in_open = 0;
+				return -ENOSYS;
+			}
+		}
+
+		if ((unsigned int)*p < KSEG0) {
+			printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
+			       "maybe an error code %d\n", (int)*p);
+ 			channel_wqs[index].in_open = 0;
+			return -ENOSYS;
 		}
 
-		if ((ret = rtlx_init(*p)) < 0)
-			return ret;
+ 		if ((ret = rtlx_init(*p)) < 0) {
+ 			channel_wqs[index].in_open = 0;
+  			return ret;
+ 		}
 	}
 
-	chan = &rtlx->channel[minor];
+	chan = &rtlx->channel[index];
 
-	if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
-		return -EBUSY;
+ 	if (chan->lx_state == RTLX_STATE_OPENED) {
+ 		channel_wqs[index].in_open = 0;
+  		return -EBUSY;
+ 	}
 
+  	chan->lx_state = RTLX_STATE_OPENED;
+ 	channel_wqs[index].in_open = 0;
 	return 0;
 }
 
-static int rtlx_release(struct inode *inode, struct file *filp)
+int rtlx_release(int index)
 {
-	int minor = MINOR(inode->i_rdev);
-
-	clear_bit(RTLX_STATE_OPENED, &rtlx->channel[minor].lx_state);
-	smp_mb__after_clear_bit();
-
+	rtlx->channel[index].lx_state = RTLX_STATE_UNUSED;
 	return 0;
 }
 
-static unsigned int rtlx_poll(struct file *file, poll_table * wait)
+unsigned int rtlx_read_poll(int index, int can_sleep)
 {
-	int minor;
-	unsigned int mask = 0;
-	struct rtlx_channel *chan;
+ 	struct rtlx_channel *chan;
 
-	minor = MINOR(file->f_dentry->d_inode->i_rdev);
-	chan = &rtlx->channel[minor];
+ 	if (rtlx == NULL)
+ 		return 0;
 
-	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
-	poll_wait(file, &channel_wqs[minor].lx_queue, wait);
+ 	chan = &rtlx->channel[index];
 
 	/* data available to read? */
-	if (chan->lx_read != chan->lx_write)
-		mask |= POLLIN | POLLRDNORM;
+	if (chan->lx_read == chan->lx_write) {
+		if (can_sleep) {
+			DECLARE_WAITQUEUE(wait, current);
 
-	/* space to write */
-	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
-		mask |= POLLOUT | POLLWRNORM;
+			/* go to sleep */
+			add_wait_queue(&channel_wqs[index].lx_queue, &wait);
 
-	return mask;
+			set_current_state(TASK_INTERRUPTIBLE);
+			while (chan->lx_read == chan->lx_write) {
+				schedule();
+
+				set_current_state(TASK_INTERRUPTIBLE);
+
+				if (sp_stopping) {
+					set_current_state(TASK_RUNNING);
+					remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+					return 0;
+				}
+			}
+
+			set_current_state(TASK_RUNNING);
+			remove_wait_queue(&channel_wqs[index].lx_queue, &wait);
+
+			/* back running */
+		}
+		else
+			return 0;
+	}
+
+	return (chan->lx_write + chan->buffer_size - chan->lx_read)
+	       % chan->buffer_size;
 }
 
-static ssize_t rtlx_read(struct file *file, char __user * buffer, size_t count,
-			 loff_t * ppos)
+static inline int write_spacefree(int read, int write, int size)
 {
-	unsigned long failed;
-	size_t fl = 0L;
-	int minor;
-	struct rtlx_channel *lx;
-	DECLARE_WAITQUEUE(wait, current);
+	if (read == write) {
+		/*
+		 * Never fill the buffer completely, so indexes are always
+		 * equal if empty and only empty, or !equal if data available
+		 */
+		return size - 1;
+	}
 
-	minor = MINOR(file->f_dentry->d_inode->i_rdev);
-	lx = &rtlx->channel[minor];
+	return ((read + size - write) % size) - 1;
+}
 
-	/* data available? */
-	if (lx->lx_write == lx->lx_read) {
-		if (file->f_flags & O_NONBLOCK)
-			return 0;	/* -EAGAIN makes cat whinge */
+unsigned int rtlx_write_poll(int index)
+{
+	struct rtlx_channel *chan = &rtlx->channel[index];
+	return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
+}
 
-		/* go to sleep */
-		add_wait_queue(&channel_wqs[minor].lx_queue, &wait);
-		set_current_state(TASK_INTERRUPTIBLE);
+static inline void copy_to(void *dst, void *src, size_t count, int user)
+{
+	if (user)
+		copy_to_user(dst, src, count);
+	else
+		memcpy(dst, src, count);
+}
 
-		while (lx->lx_write == lx->lx_read)
-			schedule();
+static inline void copy_from(void *dst, void *src, size_t count, int user)
+{
+	if (user)
+		copy_from_user(dst, src, count);
+	else
+		memcpy(dst, src, count);
+}
 
-		set_current_state(TASK_RUNNING);
-		remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);
+ssize_t rtlx_read(int index, void *buff, size_t count, int user)
+{
+	size_t fl = 0L;
+	struct rtlx_channel *lx;
 
-		/* back running */
-	}
+	if (rtlx == NULL)
+		return -ENOSYS;
+
+	lx = &rtlx->channel[index];
 
 	/* find out how much in total */
 	count = min(count,
-		    (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read) % lx->buffer_size);
+		     (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read)
+		     % lx->buffer_size);
 
 	/* then how much from the read pointer onwards */
-	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
+	fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
 
-	failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
-	if (failed) {
-		count = fl - failed;
-		goto out;
-	}
+	copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
 
 	/* and if there is anything left at the beginning of the buffer */
-	if (count - fl) {
-		failed = copy_to_user (buffer + fl, lx->lx_buffer, count - fl);
-		if (failed) {
-			count -= failed;
-			goto out;
-		}
-	}
+	if ( count - fl )
+		copy_to (buff + fl, lx->lx_buffer, count - fl, user);
 
-out:
 	/* update the index */
 	lx->lx_read += count;
 	lx->lx_read %= lx->buffer_size;
@@ -242,20 +365,101 @@ out:
 	return count;
 }
 
-static ssize_t rtlx_write(struct file *file, const char __user * buffer,
+ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
+{
+	struct rtlx_channel *rt;
+	size_t fl;
+
+	if (rtlx == NULL)
+		return(-ENOSYS);
+
+	rt = &rtlx->channel[index];
+
+	/* total number of bytes to copy */
+	count = min(count,
+		    (size_t)write_spacefree(rt->rt_read, rt->rt_write,
+					    rt->buffer_size));
+
+	/* first bit from write pointer to the end of the buffer, or count */
+	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
+
+	copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
+
+	/* if there's any left copy to the beginning of the buffer */
+	if( count - fl )
+		copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
+
+	rt->rt_write += count;
+	rt->rt_write %= rt->buffer_size;
+
+	return(count);
+}
+
+
+static int file_open(struct inode *inode, struct file *filp)
+{
+	int minor = MINOR(inode->i_rdev);
+
+	return rtlx_open(minor, (filp->f_flags & O_NONBLOCK) ? 0 : 1);
+}
+
+static int file_release(struct inode *inode, struct file *filp)
+{
+	int minor;
+	minor = MINOR(inode->i_rdev);
+
+	return rtlx_release(minor);
+}
+
+static unsigned int file_poll(struct file *file, poll_table * wait)
+{
+	int minor;
+	unsigned int mask = 0;
+
+	minor = MINOR(file->f_dentry->d_inode->i_rdev);
+
+	poll_wait(file, &channel_wqs[minor].rt_queue, wait);
+	poll_wait(file, &channel_wqs[minor].lx_queue, wait);
+
+	if (rtlx == NULL)
+		return 0;
+
+	/* data available to read? */
+	if (rtlx_read_poll(minor, 0))
+		mask |= POLLIN | POLLRDNORM;
+
+	/* space to write */
+	if (rtlx_write_poll(minor))
+		mask |= POLLOUT | POLLWRNORM;
+
+	return mask;
+}
+
+static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
+			 loff_t * ppos)
+{
+	int minor = MINOR(file->f_dentry->d_inode->i_rdev);
+
+	/* data available? */
+	if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1)) {
+		return 0;	// -EAGAIN makes cat whinge
+	}
+
+	return rtlx_read(minor, buffer, count, 1);
+}
+
+static ssize_t file_write(struct file *file, const char __user * buffer,
 			  size_t count, loff_t * ppos)
 {
-	unsigned long failed;
 	int minor;
 	struct rtlx_channel *rt;
-	size_t fl;
 	DECLARE_WAITQUEUE(wait, current);
 
 	minor = MINOR(file->f_dentry->d_inode->i_rdev);
 	rt = &rtlx->channel[minor];
 
 	/* any space left... */
-	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
+	if (!rtlx_write_poll(minor)) {
 
 		if (file->f_flags & O_NONBLOCK)
 			return -EAGAIN;
@@ -263,61 +467,64 @@ static ssize_t rtlx_write(struct file *file, const char __user * buffer,
 		add_wait_queue(&channel_wqs[minor].rt_queue, &wait);
 		set_current_state(TASK_INTERRUPTIBLE);
 
-		while (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size))
+		while (!rtlx_write_poll(minor))
 			schedule();
 
 		set_current_state(TASK_RUNNING);
 		remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
 	}
 
-	/* total number of bytes to copy */
-	count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );
-
-	/* first bit from write pointer to the end of the buffer, or count */
-	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
-
-	failed = copy_from_user(&rt->rt_buffer[rt->rt_write], buffer, fl);
-	if (failed) {
-		count = fl - failed;
-		goto out;
-	}
-
-	/* if there's any left copy to the beginning of the buffer */
-	if (count - fl) {
-		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
-		if (failed) {
-			count -= failed;
-			goto out;
-		}
-	}
-
-out:
-	rt->rt_write += count;
-	rt->rt_write %= rt->buffer_size;
-
-	return count;
+	return rtlx_write(minor, (void *)buffer, count, 1);
 }
 
 static struct file_operations rtlx_fops = {
-	.owner		= THIS_MODULE,
-	.open		= rtlx_open,
-	.release	= rtlx_release,
-	.write		= rtlx_write,
-	.read		= rtlx_read,
-	.poll		= rtlx_poll
+	.owner =   THIS_MODULE,
+	.open =    file_open,
+	.release = file_release,
+	.write =   file_write,
+	.read =    file_read,
+	.poll =    file_poll
 };
 
+static struct irqaction rtlx_irq = {
+	.handler	= rtlx_interrupt,
+	.flags		= SA_INTERRUPT,
+	.name		= "RTLX",
+};
+
+static int rtlx_irq_num = MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ;
+
 static char register_chrdev_failed[] __initdata =
 	KERN_ERR "rtlx_module_init: unable to register device\n";
 
-static int __init rtlx_module_init(void)
+static int rtlx_module_init(void)
 {
+	int i;
+
 	major = register_chrdev(0, module_name, &rtlx_fops);
 	if (major < 0) {
 		printk(register_chrdev_failed);
 		return major;
 	}
 
+	/* initialise the wait queues */
+	for (i = 0; i < RTLX_CHANNELS; i++) {
+		init_waitqueue_head(&channel_wqs[i].rt_queue);
+		init_waitqueue_head(&channel_wqs[i].lx_queue);
+		channel_wqs[i].in_open = 0;
+	}
+
+	/* set up notifiers */
+	notify.start = starting;
+	notify.stop = stopping;
+	vpe_notify(RTLX_TARG_VPE, &notify);
+
+	if (cpu_has_vint)
+		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
+
+	rtlx_irq.dev_id = rtlx;
+	setup_irq(rtlx_irq_num, &rtlx_irq);
+
 	return 0;
 }
 
@@ -330,5 +537,5 @@ module_init(rtlx_module_init);
 module_exit(rtlx_module_exit);
 
 MODULE_DESCRIPTION("MIPS RTLX");
-MODULE_AUTHOR("Elizabeth Clarke, MIPS Technologies, Inc.");
+MODULE_AUTHOR("Elizabeth Oldham, MIPS Technologies, Inc.");
 MODULE_LICENSE("GPL");