Hi Sergei,
On Wed, Jun 9, 2021 at 5:09 PM Sergei Shtylyov
<sergei.shtylyov@xxxxxxxxx> wrote:
> 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;
Because chan_tx and cookie_tx do not exist if CONFIG_SERIAL_SH_SCI_DMA
is disabled.
Yes, that's why all the DMA code in this driver (.c file) is protected by
#ifdef CONFIG_SERIAL_SH_SCI_DMA.
> > + }
> > +#endif
> > }
> >
> > static void sci_start_rx(struct uart_port *port)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
