On 6/9/21 4:49 AM, Yoshihiro Shimoda wrote:
> Stop dmaengine transfer in sci_stop_tx(). Otherwise, the following
> message is possible output when system enters suspend and while
> transferring data, because clearing TIE bit in SCSCR is not able to
> stop any dmaengine transfer.
>
> sh-sci e6550000.serial: ttySC1: Unable to drain transmitter
>
> Note that this patch uses dmaengine_terminate_async() so that
> we can apply this patch into longterm kernel v4.9.x or later.
>
> Fixes: 73a19e4c0301 ("serial: sh-sci: Add DMA support.")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> ---
> Changes from v2:
> - Don't use a macro.
> - Revise the commit descrption.
> https://lore.kernel.org/linux-renesas-soc/20210604095704.756190-1-yoshihiro.shimoda.uh@xxxxxxxxxxx/
>
> Changes from v1:
> - Don't put #ifdef in the .c file.
> - Update the commit description.
> https://lore.kernel.org/linux-renesas-soc/20210602114108.510527-1-yoshihiro.shimoda.uh@xxxxxxxxxxx/
>
> drivers/tty/serial/sh-sci.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
> index 4baf1316ea72..2d5487bf6855 100644
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -610,6 +610,14 @@ static void sci_stop_tx(struct uart_port *port)
> ctrl &= ~SCSCR_TIE;
>
> serial_port_out(port, SCSCR, ctrl);
> +
> +#ifdef CONFIG_SERIAL_SH_SCI_DMA
Why not use IS_ENABLED() instead? Gets rid of #ifdef. :-)
> + if (to_sci_port(port)->chan_tx &&
> + !dma_submit_error(to_sci_port(port)->cookie_tx)) {
> + dmaengine_terminate_async(to_sci_port(port)->chan_tx);
> + to_sci_port(port)->cookie_tx = -EINVAL;
> + }
> +#endif
> }
>
> static void sci_start_rx(struct uart_port *port)
MBR, Sergei
