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

[Peter Maydell]

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>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: Martin Kaiser <martin@kaiser.cx>



Applied to target-arm.next, thanks.

-- PMM