mailbox: Don't unnecessarily re-arm the polling timer

poll_txdone() will unconditionally re-arm the polling timer if there was
an active request, even if the active request completed and no other
requests were submitted.  This is fixed by:
 - only re-arming the timer if the controller reported that the current
   transmission has not completed, and,
 - moving the call to poll_txdone() into msg_submit() so that the
   controller gets polled (and the timer re-armed, if necessary) whenever
   a new message is submitted.

Signed-off-by: Andrew Bresticker <abrestic@chromium.org>
Reviewed-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index afcb430508ec..c281e5562876 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -28,6 +28,8 @@
 static LIST_HEAD(mbox_cons);
 static DEFINE_MUTEX(con_mutex);
 
+static void poll_txdone(unsigned long data);
+
 static int add_to_rbuf(struct mbox_chan *chan, void *mssg)
 {
         int idx;
@@ -60,7 +62,7 @@ static void msg_submit(struct mbox_chan *chan)
         unsigned count, idx;
         unsigned long flags;
         void *data;
-        int err;
+        int err = -EBUSY;
 
         spin_lock_irqsave(&chan->lock, flags);
 
@@ -84,6 +86,9 @@ static void msg_submit(struct mbox_chan *chan)
         }
 exit:
         spin_unlock_irqrestore(&chan->lock, flags);
+
+        if (!err && chan->txdone_method == TXDONE_BY_POLL)
+                poll_txdone((unsigned long)chan->mbox);
 }
 
 static void tx_tick(struct mbox_chan *chan, int r)
@@ -117,10 +122,11 @@ static void poll_txdone(unsigned long data)
                 struct mbox_chan *chan = &mbox->chans[i];
 
                 if (chan->active_req && chan->cl) {
-                        resched = true;
                         txdone = chan->mbox->ops->last_tx_done(chan);
                         if (txdone)
                                 tx_tick(chan, 0);
+                        else
+                                resched = true;
                 }
         }
 
@@ -252,9 +258,6 @@ int mbox_send_message(struct mbox_chan *chan, void *mssg)
 
         msg_submit(chan);
 
-        if (chan->txdone_method == TXDONE_BY_POLL)
-                poll_txdone((unsigned long)chan->mbox);
-
         if (chan->cl->tx_block && chan->active_req) {
                 unsigned long wait;
                 int ret;