2022-02-14 20:14:04

by Thierry Reding

Subject: [PATCH] mailbox: tegra-hsp: Flush whole channel

From: Pekka Pessi <[email protected]>

The txdone can re-fill the mailbox. Keep polling the mailbox during the
flush until all the messages have been delivered.

Signed-off-by: Pekka Pessi <[email protected]>
Signed-off-by: Thierry Reding <[email protected]>
---
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 acd0675da681..78f7265039c6 100644
--- a/drivers/mailbox/tegra-hsp.c
+++ b/drivers/mailbox/tegra-hsp.c
@@ -412,6 +412,11 @@ 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;
}

--
2.35.1

2022-02-14 21:12:49

by Jon Hunter

Subject: Re: [PATCH] mailbox: tegra-hsp: Flush whole channel

On 14/02/2022 15:32, Thierry Reding wrote:
> From: Pekka Pessi <[email protected]>
>
> The txdone can re-fill the mailbox. Keep polling the mailbox during the
> flush until all the messages have been delivered.
>
> Signed-off-by: Pekka Pessi <[email protected]>
> Signed-off-by: Thierry Reding <[email protected]>
> ---
> 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 acd0675da681..78f7265039c6 100644
> --- a/drivers/mailbox/tegra-hsp.c
> +++ b/drivers/mailbox/tegra-hsp.c
> @@ -412,6 +412,11 @@ 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;
> }
>


Thanks!

Tested-by: Jon Hunter <[email protected]>

Maybe worth mentioning that this fixes an annoying issue with the TCU
(Tegra Combined UART) where the output is getting truncated. I think we
should add the following fixes tag and mark for stable too.

Fixes: 91b1b1c3da8a ("mailbox: tegra-hsp: Add support for shared mailboxes")

Jon

--
nvpublic