1 files changed, 285 insertions, 208 deletions

diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 1d855112bac..31b1b763cb2 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -1,330 +1,407 @@
 /*
- * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
- *
- *  This program is free software; you can distribute it and/or modify it
- *  under the terms of the GNU General Public License (Version 2) as
- *  published by the Free Software Foundation.
- *
- *  This program is distributed in the hope it will be useful, but WITHOUT
- *  ANY WARRANTY; 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.,
- *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
  *
+ * Copyright (C) 2005 MIPS Technologies, Inc.  All rights reserved.
+ * Copyright (C) 2005, 06 Ralf Baechle (ralf@linux-mips.org)
+ * Copyright (C) 2013 Imagination Technologies Ltd.
  */
-
 #include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/fs.h>
-#include <linux/init.h>
-#include <linux/poll.h>
-#include <linux/sched.h>
-#include <linux/wait.h>
+#include <linux/syscalls.h>
+#include <linux/moduleloader.h>
+#include <linux/atomic.h>
 #include <asm/mipsmtregs.h>
-#include <asm/bitops.h>
-#include <asm/cpu.h>
+#include <asm/mips_mt.h>
 #include <asm/processor.h>
 #include <asm/rtlx.h>
-#include <asm/uaccess.h>
-
-#define RTLX_TARG_VPE 1
+#include <asm/setup.h>
+#include <asm/vpe.h>
 
-static struct rtlx_info *rtlx;
-static int major;
-static char module_name[] = "rtlx";
-static struct irqaction irq;
-static int irq_num;
+static int sp_stopping;
+struct rtlx_info *rtlx;
+struct chan_waitqueues channel_wqs[RTLX_CHANNELS];
+struct vpe_notifications rtlx_notify;
+void (*aprp_hook)(void) = NULL;
+EXPORT_SYMBOL(aprp_hook);
 
-static inline int spacefree(int read, int write, int size)
+static void __used dump_rtlx(void)
 {
-	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;
-}
+	int i;
 
-static struct chan_waitqueues {
-	wait_queue_head_t rt_queue;
-	wait_queue_head_t lx_queue;
-} channel_wqs[RTLX_CHANNELS];
+	pr_info("id 0x%lx state %d\n", rtlx->id, rtlx->state);
 
-extern void *vpe_get_shared(int index);
+	for (i = 0; i < RTLX_CHANNELS; i++) {
+		struct rtlx_channel *chan = &rtlx->channel[i];
 
-static void rtlx_dispatch(struct pt_regs *regs)
-{
-	do_IRQ(MIPSCPU_INT_BASE + MIPS_CPU_RTLX_IRQ, regs);
-}
+		pr_info(" rt_state %d lx_state %d buffer_size %d\n",
+			chan->rt_state, chan->lx_state, chan->buffer_size);
 
-static irqreturn_t rtlx_interrupt(int irq, void *dev_id, struct pt_regs *regs)
-{
-	int i;
+		pr_info(" rt_read %d rt_write %d\n",
+			chan->rt_read, chan->rt_write);
 
-	for (i = 0; i < RTLX_CHANNELS; i++) {
-		struct rtlx_channel *chan = &rtlx->channel[i];
+		pr_info(" lx_read %d lx_write %d\n",
+			chan->lx_read, chan->lx_write);
 
-		if (chan->lx_read != chan->lx_write)
-			wake_up_interruptible(&channel_wqs[i].lx_queue);
+		pr_info(" rt_buffer <%s>\n", chan->rt_buffer);
+		pr_info(" lx_buffer <%s>\n", chan->lx_buffer);
 	}
-
-	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)
 {
-	int i;
-
 	if (rtlxi->id != RTLX_ID) {
-		printk(KERN_WARNING "no valid RTLX id at 0x%p\n", rtlxi);
+		pr_err("no valid RTLX id at 0x%p 0x%lx\n", rtlxi, rtlxi->id);
 		return -ENOEXEC;
 	}
 
-	/* 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);
-	}
+	rtlx = rtlxi;
 
-	/* set up for interrupt handling */
-	memset(&irq, 0, sizeof(struct irqaction));
+	return 0;
+}
 
-	if (cpu_has_vint)
-		set_vi_handler(MIPS_CPU_RTLX_IRQ, rtlx_dispatch);
+/* notifications */
+void rtlx_starting(int vpe)
+{
+	int i;
+	sp_stopping = 0;
 
-	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);
+	/* force a reload of rtlx */
+	rtlx = NULL;
 
-	rtlx = rtlxi;
+	/* wake up any sleeping rtlx_open's */
+	for (i = 0; i < RTLX_CHANNELS; i++)
+		wake_up_interruptible(&channel_wqs[i].lx_queue);
+}
 
-	return 0;
+void rtlx_stopping(int vpe)
+{
+	int i;
+
+	sp_stopping = 1;
+	for (i = 0; i < RTLX_CHANNELS; i++)
+		wake_up_interruptible(&channel_wqs[i].lx_queue);
 }
 
-/* only allow one open process at a time to open each channel */
-static int rtlx_open(struct inode *inode, struct file *filp)
+
+int rtlx_open(int index, int can_sleep)
 {
-	int minor, ret;
+	struct rtlx_info **p;
 	struct rtlx_channel *chan;
+	enum rtlx_state state;
+	int ret = 0;
 
-	/* assume only 1 device at the mo. */
-	minor = MINOR(inode->i_rdev);
+	if (index >= RTLX_CHANNELS) {
+		pr_debug(KERN_DEBUG "rtlx_open index out of range\n");
+		return -ENOSYS;
+	}
+
+	if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
+		pr_debug(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
+		ret = -EBUSY;
+		goto out_fail;
+	}
 
 	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;
+		p = vpe_get_shared(aprp_cpu_index());
+		if (p == NULL) {
+			if (can_sleep) {
+				ret = __wait_event_interruptible(
+					channel_wqs[index].lx_queue,
+					(p = vpe_get_shared(aprp_cpu_index())));
+				if (ret)
+					goto out_fail;
+			} else {
+				pr_debug("No SP program loaded, and device opened with O_NONBLOCK\n");
+				ret = -ENOSYS;
+				goto out_fail;
+			}
 		}
 
+		smp_rmb();
 		if (*p == NULL) {
-			printk(KERN_ERR "vpe_shared %p %p\n", p, *p);
-			return -EFAULT;
+			if (can_sleep) {
+				DEFINE_WAIT(wait);
+
+				for (;;) {
+					prepare_to_wait(
+						&channel_wqs[index].lx_queue,
+						&wait, TASK_INTERRUPTIBLE);
+					smp_rmb();
+					if (*p != NULL)
+						break;
+					if (!signal_pending(current)) {
+						schedule();
+						continue;
+					}
+					ret = -ERESTARTSYS;
+					goto out_fail;
+				}
+				finish_wait(&channel_wqs[index].lx_queue,
+					    &wait);
+			} else {
+				pr_err(" *vpe_get_shared is NULL. Has an SP program been loaded?\n");
+				ret = -ENOSYS;
+				goto out_fail;
+			}
 		}
 
-		if ((ret = rtlx_init(*p)) < 0)
-			return ret;
+		if ((unsigned int)*p < KSEG0) {
+			pr_warn("vpe_get_shared returned an invalid pointer maybe an error code %d\n",
+				(int)*p);
+			ret = -ENOSYS;
+			goto out_fail;
+		}
+
+		ret = rtlx_init(*p);
+		if (ret < 0)
+			goto out_ret;
 	}
 
-	chan = &rtlx->channel[minor];
+	chan = &rtlx->channel[index];
 
-	if (test_and_set_bit(RTLX_STATE_OPENED, &chan->lx_state))
-		return -EBUSY;
+	state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
+	if (state == RTLX_STATE_OPENED) {
+		ret = -EBUSY;
+		goto out_fail;
+	}
 
-	return 0;
+out_fail:
+	smp_mb();
+	atomic_dec(&channel_wqs[index].in_open);
+	smp_mb();
+
+out_ret:
+	return ret;
 }
 
-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();
-
+	if (rtlx == NULL) {
+		pr_err("rtlx_release() with null rtlx\n");
+		return 0;
+	}
+	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;
 
-	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;
-
-	/* space to write */
-	if (spacefree(chan->rt_read, chan->rt_write, chan->buffer_size))
-		mask |= POLLOUT | POLLWRNORM;
+	if (chan->lx_read == chan->lx_write) {
+		if (can_sleep) {
+			int ret = __wait_event_interruptible(
+				channel_wqs[index].lx_queue,
+				(chan->lx_read != chan->lx_write) ||
+				sp_stopping);
+			if (ret)
+				return ret;
+
+			if (sp_stopping)
+				return 0;
+		} else
+			return 0;
+	}
 
-	return mask;
+	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);
+ssize_t rtlx_read(int index, void __user *buff, size_t count)
+{
+	size_t lx_write, fl = 0L;
+	struct rtlx_channel *lx;
+	unsigned long failed;
 
-		while (lx->lx_write == lx->lx_read)
-			schedule();
+	if (rtlx == NULL)
+		return -ENOSYS;
 
-		set_current_state(TASK_RUNNING);
-		remove_wait_queue(&channel_wqs[minor].lx_queue, &wait);
+	lx = &rtlx->channel[index];
 
-		/* back running */
-	}
+	mutex_lock(&channel_wqs[index].mutex);
+	smp_rmb();
+	lx_write = lx->lx_write;
 
 	/* 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_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);
 
-	failed = copy_to_user (buffer, &lx->lx_buffer[lx->lx_read], fl);
-	if (failed) {
-		count = fl - failed;
+	failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
+	if (failed)
 		goto out;
-	}
 
 	/* 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)
+		failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
 
 out:
-	/* update the index */
-	lx->lx_read += count;
-	lx->lx_read %= lx->buffer_size;
+	count -= failed;
+
+	smp_wmb();
+	lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
+	smp_wmb();
+	mutex_unlock(&channel_wqs[index].mutex);
 
 	return count;
 }
 
-static ssize_t rtlx_write(struct file *file, const char __user * buffer,
-			  size_t count, loff_t * ppos)
+ssize_t rtlx_write(int index, const void __user *buffer, size_t count)
 {
-	unsigned long failed;
-	int minor;
 	struct rtlx_channel *rt;
+	unsigned long failed;
+	size_t rt_read;
 	size_t fl;
-	DECLARE_WAITQUEUE(wait, current);
 
-	minor = MINOR(file->f_dentry->d_inode->i_rdev);
-	rt = &rtlx->channel[minor];
+	if (rtlx == NULL)
+		return -ENOSYS;
 
-	/* any space left... */
-	if (!spacefree(rt->rt_read, rt->rt_write, rt->buffer_size)) {
+	rt = &rtlx->channel[index];
 
-		if (file->f_flags & O_NONBLOCK)
-			return -EAGAIN;
-
-		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))
-			schedule();
-
-		set_current_state(TASK_RUNNING);
-		remove_wait_queue(&channel_wqs[minor].rt_queue, &wait);
-	}
+	mutex_lock(&channel_wqs[index].mutex);
+	smp_rmb();
+	rt_read = rt->rt_read;
 
 	/* total number of bytes to copy */
-	count = min(count, (size_t)spacefree(rt->rt_read, rt->rt_write, rt->buffer_size) );
+	count = min_t(size_t, count, write_spacefree(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;
+	failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
+	if (failed)
 		goto out;
-	}
 
 	/* if there's any left copy to the beginning of the buffer */
-	if (count - fl) {
+	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;
+	count -= failed;
+
+	smp_wmb();
+	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
+	smp_wmb();
+	mutex_unlock(&channel_wqs[index].mutex);
+
+	_interrupt_sp();
 
 	return count;
 }
 
-static struct file_operations rtlx_fops = {
-	.owner		= THIS_MODULE,
-	.open		= rtlx_open,
-	.release	= rtlx_release,
-	.write		= rtlx_write,
-	.read		= rtlx_read,
-	.poll		= rtlx_poll
-};
 
-static char register_chrdev_failed[] __initdata =
-	KERN_ERR "rtlx_module_init: unable to register device\n";
+static int file_open(struct inode *inode, struct file *filp)
+{
+	return rtlx_open(iminor(inode), (filp->f_flags & O_NONBLOCK) ? 0 : 1);
+}
 
-static int __init rtlx_module_init(void)
+static int file_release(struct inode *inode, struct file *filp)
 {
-	major = register_chrdev(0, module_name, &rtlx_fops);
-	if (major < 0) {
-		printk(register_chrdev_failed);
-		return major;
-	}
+	return rtlx_release(iminor(inode));
+}
 
-	return 0;
+static unsigned int file_poll(struct file *file, poll_table *wait)
+{
+	int minor = iminor(file_inode(file));
+	unsigned int mask = 0;
+
+	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 void __exit rtlx_module_exit(void)
+static ssize_t file_read(struct file *file, char __user *buffer, size_t count,
+			 loff_t *ppos)
 {
-	unregister_chrdev(major, module_name);
+	int minor = iminor(file_inode(file));
+
+	/* data available? */
+	if (!rtlx_read_poll(minor, (file->f_flags & O_NONBLOCK) ? 0 : 1))
+		return 0;	/* -EAGAIN makes 'cat' whine */
+
+	return rtlx_read(minor, buffer, count);
 }
 
+static ssize_t file_write(struct file *file, const char __user *buffer,
+			  size_t count, loff_t *ppos)
+{
+	int minor = iminor(file_inode(file));
+
+	/* any space left... */
+	if (!rtlx_write_poll(minor)) {
+		int ret;
+
+		if (file->f_flags & O_NONBLOCK)
+			return -EAGAIN;
+
+		ret = __wait_event_interruptible(channel_wqs[minor].rt_queue,
+					   rtlx_write_poll(minor));
+		if (ret)
+			return ret;
+	}
+
+	return rtlx_write(minor, buffer, count);
+}
+
+const struct file_operations rtlx_fops = {
+	.owner =   THIS_MODULE,
+	.open =    file_open,
+	.release = file_release,
+	.write =   file_write,
+	.read =    file_read,
+	.poll =    file_poll,
+	.llseek =  noop_llseek,
+};
+
 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");