mailbox: skip complete wait event if timer expired

If a wait_for_completion_timeout() call returns due to a timeout,
complete() can get called after returning from the wait which is
incorrect and can cause subsequent transmissions on a channel to fail.
Since the wait_for_completion_timeout() sees the completion variable
is non-zero caused by the erroneous/spurious complete() call, and
it immediately returns without waiting for the time as expected by the
client.

This patch fixes the issue by skipping complete() call for the timer
expiry.

Fixes: 2b6d83e2b8b7 ("mailbox: Introduce framework for mailbox")
Reported-by: Alexey Klimov <alexey.klimov@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 28a34cf117dc4e11fe71af4d0021f7660f4d755b..49e5dadd5733de42bff073b9c9a99d32015f01df 100644 (file)
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -107,7 +107,7 @@ static void tx_tick(struct mbox_chan *chan, int r)
        if (mssg && chan->cl->tx_done)
                chan->cl->tx_done(chan->cl, mssg, r);
 
-       if (chan->cl->tx_block)
+       if (r != -ETIME && chan->cl->tx_block)
                complete(&chan->tx_complete);
 }
 
@@ -271,8 +271,8 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 
                ret = wait_for_completion_timeout(&chan->tx_complete, wait);
                if (ret == 0) {
-                       t = -EIO;
-                       tx_tick(chan, -EIO);
+                       t = -ETIME;
+                       tx_tick(chan, t);
                }
        }