[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");