Re: [PATCH v2] mailbox: tegra-hsp: Flush whole channel

[Jon Hunter]

Hi Jassi,

On 02/03/2022 15:04, Thierry Reding wrote:
> From: Pekka Pessi <ppessi@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>
> Fixes: 91b1b1c3da8a ("mailbox: tegra-hsp: Add support for shared mailboxes")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> Changes in v2:
> - add Fixes: line
> - Cc stable
>
>   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;
>   		}
>   


Any feedback on this? Can we queue this up for v5.18?

Thanks
Jon

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nvpublic