Commit 8d3a7b20 authored Mar 02, 2022 by Pekka Pessi Committed by Greg Kroah-Hartman Apr 15, 2022

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 <ppessi@nvidia.com>
Tested-by: Jon Hunter <jonathanh@nvidia.com>
Fixes: 91b1b1c3 ("mailbox: tegra-hsp: Add support for shared mailboxes")
Cc: stable@vger.kernel.org
Signed-off-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 28c8fd84

drivers/mailbox/tegra-hsp.c

+5 −0

Original line number	Original line	Diff line number	Diff line
	@@ -403,6 +403,11 @@ static int tegra_hsp_mailbox_flush(struct mbox_chan *chan,
	value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX);		value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX);
	if ((value & HSP_SM_SHRD_MBOX_FULL) == 0) {		if ((value & HSP_SM_SHRD_MBOX_FULL) == 0) {
	mbox_chan_txdone(chan, 0);		mbox_chan_txdone(chan, 0);

			/* Wait until channel is empty */
			if (chan->active_req != NULL)
			continue;

	return 0;		return 0;
	}		}