Re: [PATCH v3] imx_serial: set wake bit when we receive a data byte

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 19/6/23 12:36, Peter Maydell wrote:
> On Thu, 15 Jun 2023 at 15:24, Martin Kaiser <martin@kaiser.cx> wrote:
>>
>> The Linux kernel added a flood check for RX data recently in commit
>> 496a4471b7c3 ("serial: imx: work-around for hardware RX flood"). This
>> check uses the wake bit in the UART status register 2. The wake bit
>> indicates that the receiver detected a start bit on the RX line. If the
>> kernel sees a number of RX interrupts without the wake bit being set, it
>> treats this as spurious data and resets the UART port. imx_serial does
>> never set the wake bit and triggers the kernel's flood check.
>>
>> This patch adds support for the wake bit. wake is set when we receive a
>> new character (it's not set for break events). It seems that wake is
>> cleared by the kernel driver, the hardware does not have to clear it
>> automatically after data was read.
>>
>> The wake bit can be configured as an interrupt source. Support this
>> mechanism as well.
>>
>> Co-developed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

>> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
>> Signed-off-by: Martin Kaiser <martin@kaiser.cx>
> 
> 
> 
> Applied to target-arm.next, thanks.
> 
> -- PMM