From 8d3a7b206458801eb842f97c5d4ba59fd911c71d Mon Sep 17 00:00:00 2001 From: Pekka Pessi Date: Wed, 2 Mar 2022 16:04:24 +0100 Subject: [PATCH] mailbox: tegra-hsp: Flush whole channel commit 60de2d2dc284e0dd1c2c897d08625bde24ef3454 upstream. The txdone can re-fill the mailbox. Keep polling the mailbox during the flush until all the messages have been delivered. This fixes an issue with the Tegra Combined UART (TCU) where output can get truncated under high traffic load. Signed-off-by: Pekka Pessi Tested-by: Jon Hunter Fixes: 91b1b1c3da8a ("mailbox: tegra-hsp: Add support for shared mailboxes") Cc: stable@vger.kernel.org Signed-off-by: Thierry Reding Reviewed-by: Jon Hunter Signed-off-by: Jassi Brar Signed-off-by: Greg Kroah-Hartman --- drivers/mailbox/tegra-hsp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/mailbox/tegra-hsp.c b/drivers/mailbox/tegra-hsp.c index 834b35dc3b13..e9b392dc09bc 100644 --- a/drivers/mailbox/tegra-hsp.c +++ b/drivers/mailbox/tegra-hsp.c @@ -403,6 +403,11 @@ static int tegra_hsp_mailbox_flush(struct mbox_chan *chan, value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX); if ((value & HSP_SM_SHRD_MBOX_FULL) == 0) { mbox_chan_txdone(chan, 0); + + /* Wait until channel is empty */ + if (chan->active_req != NULL) + continue; + return 0; }