mailbox: handle empty message in tx_tick

We already check if the message is empty before calling the client
tx_done callback. Calling completion on a wait event is also invalid
if the message is empty.

This patch moves the existing empty message check earlier.

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

1 files changed, 4 insertions, 1 deletions

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 49e5dadd5733..9dfbf7ea10a2 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -103,8 +103,11 @@ static void tx_tick(struct mbox_chan *chan, int r)
         /* Submit next message */
         msg_submit(chan);
 
+        if (!mssg)
+                return;
+
         /* Notify the client */
-        if (mssg && chan->cl->tx_done)
+        if (chan->cl->tx_done)
                 chan->cl->tx_done(chan->cl, mssg, r);
 
         if (r != -ETIME && chan->cl->tx_block)