mailbox: check ->last_tx_done for NULL in case of timer-based polling

It is allowed by code to register mailbox controller that sets txdone_poll
flag to request timer-based polling with missed ->last_tx_done() method.
If such thing happens and since presence of last_tx_done() is not checked
it will fail in hrtimer callback function txdone_hrtimer() when first
message will be transmitted.

This patch adds check for this method and logging of error on
registration of mailbox controller if it requested timer-based polling.

Signed-off-by: Alexey Klimov <alexey.klimov@arm.com>
Acked-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 4671f8a128723010dafe2d2f6f48df75a492c9fb..59b722177bf7b8ad07a00a5c2930df9ca84e74a1 100644 (file)
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -453,6 +453,12 @@ int mbox_controller_register(struct mbox_controller *mbox)
                txdone = TXDONE_BY_ACK;
 
        if (txdone == TXDONE_BY_POLL) {
+
+               if (!mbox->ops->last_tx_done) {
+                       dev_err(mbox->dev, "last_tx_done method is absent\n");
+                       return -EINVAL;
+               }
+
                hrtimer_init(&mbox->poll_hrt, CLOCK_MONOTONIC,
                             HRTIMER_MODE_REL);
                mbox->poll_hrt.function = txdone_hrtimer;