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

[Jon Hunter <jonathanh@nvidia.com>]

On 10/03/2022 16:51, Jon Hunter wrote:
> Hi Jassi,
> 
> On 02/03/2022 15:04, Thierry Reding wrote:
>> From: Pekka Pessi <ppessi@nvidia.com>
>>
>> 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: 91b1b1c3da8a ("mailbox: tegra-hsp: Add support for shared 
>> mailboxes")
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Thierry Reding <treding@nvidia.com>
>> ---
>> 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?

Feel free to add my ...

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>

Jon

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