From 1b102d2fe17884d46cb555474310c8c942014d58 Mon Sep 17 00:00:00 2001 From: Marek Vasut Date: Mon, 27 Oct 2025 17:38:38 +0100 Subject: [PATCH] mailbox: Allow operation without .recv callback Some shared memory mailboxes may have empty receive operation, because the data are polled by upper layers directly from the shared memory region, and there is no completion interrupt or bit of any sort. Allow empty .recv callback, and if the .recv callback is empty, exit from mbox_recv() right away, because any polling for completion here would be meaningless. Signed-off-by: Marek Vasut Reviewed-by: Alice Guo --- drivers/mailbox/mailbox-uclass.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/mailbox/mailbox-uclass.c b/drivers/mailbox/mailbox-uclass.c index 4bf4987ce0a..fef437a4281 100644 --- a/drivers/mailbox/mailbox-uclass.c +++ b/drivers/mailbox/mailbox-uclass.c @@ -132,6 +132,15 @@ int mbox_recv(struct mbox_chan *chan, void *data, ulong timeout_us) debug("%s(chan=%p, data=%p, timeout_us=%ld)\n", __func__, chan, data, timeout_us); + /* + * Some shared memory mailboxes may have empty receive operation, + * because the data are polled by upper layers directly from the + * shared memory region, and there is no completion interrupt or + * bit of any sort. + */ + if (!ops->recv) + return 0; + start_time = timer_get_us(); /* * Account for partial us ticks, but if timeout_us is 0, ensure we -- 2.47.3