Hi Geert-san, Sergei-san,
> From: Geert Uytterhoeven, Sent: Thursday, June 10, 2021 12:30 AM
> 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>
> > > ---
> > >
> > > 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.
This is a nit though, chan_tx always exists.
> Yes, that's why all the DMA code in this driver (.c file) is protected by
> #ifdef CONFIG_SERIAL_SH_SCI_DMA.
I'm thinking we have to remove #ifdef from sh-sci.c file at first...
Best regards,
Yoshihiro Shimoda
