V4L/DVB (11617): cx18: Set up to wait for a one-shot response before sending a firmwa...

When sending an outgoing firmware command, prepare to wait before we raise the
interrupt, so we don't miss the wake_up() on the acknowledgment.  When waiting
for the acknowledgement, there is no need to loop around schedule(), as there
will only be one interrupt, and hence one wake_up(), issued.

Signed-off-by: Andy Walls <awalls@radix.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/cx18/cx18-mailbox.c b/drivers/media/video/cx18/cx18-mailbox.c
index 2a4d435..df7d61d 100644 (file)
--- a/drivers/media/video/cx18/cx18-mailbox.c
+++ b/drivers/media/video/cx18/cx18-mailbox.c
@@ -478,9 +478,10 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
        u32 __iomem *xpu_state;
        wait_queue_head_t *waitq;
        struct mutex *mb_lock;
-       long int timeout, ret;
+       unsigned long int t0, timeout, ret;
        int i;
        char argstr[MAX_MB_ARGUMENTS*11+1];
+       DEFINE_WAIT(w);
 
        if (info == NULL) {
                CX18_WARN("unknown cmd %x\n", cmd);
@@ -562,25 +563,49 @@ static int cx18_api_call(struct cx18 *cx, u32 cmd, int args, u32 data[])
 
        CX18_DEBUG_HI_IRQ("sending interrupt SW1: %x to send %s\n",
                          irq, info->name);
+
+       /* So we don't miss the wakeup, prepare to wait before notifying fw */
+       prepare_to_wait(waitq, &w, TASK_UNINTERRUPTIBLE);
        cx18_write_reg_expect(cx, irq, SW1_INT_SET, irq, irq);
 
-       ret = wait_event_timeout(
-                      *waitq,
-                      cx18_readl(cx, &mb->ack) == cx18_readl(cx, &mb->request),
-                      timeout);
+       t0 = jiffies;
+       ack = cx18_readl(cx, &mb->ack);
+       if (ack != req) {
+               schedule_timeout(timeout);
+               ret = jiffies - t0;
+               ack = cx18_readl(cx, &mb->ack);
+       } else {
+               ret = jiffies - t0;
+       }
+
+       finish_wait(waitq, &w);
 
-       if (ret == 0) {
-               /* Timed out */
+       if (req != ack) {
                mutex_unlock(mb_lock);
-               CX18_DEBUG_WARN("sending %s timed out waiting %d msecs for RPU "
-                               "acknowledgement\n",
-                               info->name, jiffies_to_msecs(timeout));
+               if (ret >= timeout) {
+                       /* Timed out */
+                       CX18_DEBUG_WARN("sending %s timed out waiting %d msecs "
+                                       "for RPU acknowledgement\n",
+                                       info->name, jiffies_to_msecs(ret));
+               } else {
+                       CX18_DEBUG_WARN("woken up before mailbox ack was ready "
+                                       "after submitting %s to RPU.  only "
+                                       "waited %d msecs on req %u but awakened"
+                                       " with unmatched ack %u\n",
+                                       info->name,
+                                       jiffies_to_msecs(ret),
+                                       req, ack);
+               }
                return -EINVAL;
        }
 
-       if (ret != timeout)
+       if (ret >= timeout)
+               CX18_DEBUG_WARN("failed to be awakened upon RPU acknowledgment "
+                               "sending %s; timed out waiting %d msecs\n",
+                               info->name, jiffies_to_msecs(ret));
+       else
                CX18_DEBUG_HI_API("waited %u msecs for %s to be acked\n",
-                                 jiffies_to_msecs(timeout-ret), info->name);
+                                 jiffies_to_msecs(ret), info->name);
 
        /* Collect data returned by the XPU */
        for (i = 0; i < MAX_MB_ARGUMENTS; i++)