| Message ID | 1440181546-7334-2-git-send-email-geert+renesas@glider.be (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Geert Uytterhoeven |
| Headers | show |
Hi Geert, Thank you for the patch. On Friday 21 August 2015 20:25:43 Geert Uytterhoeven wrote: > Make sure the transmitter and receiver are stopped when shutting down > the port, to avoid new RX DMA requests to arrive. > > Inspired by a patch in the BSP by Koji Matsuoka > <koji.matsuoka.xm@renesas.com>. > > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> > --- > v3: > - No changes, > > v2: > - New. > --- > drivers/tty/serial/sh-sci.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c > index d8b73e791a554823..0622cafaf1c71cab 100644 > --- a/drivers/tty/serial/sh-sci.c > +++ b/drivers/tty/serial/sh-sci.c > @@ -1820,12 +1820,16 @@ static void sci_shutdown(struct uart_port *port) > { > struct sci_port *s = to_sci_port(port); > unsigned long flags; > + u16 scscr; > > dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); > > spin_lock_irqsave(&port->lock, flags); > sci_stop_rx(port); > sci_stop_tx(port); > + scscr = serial_port_in(port, SCSCR); > + scscr &= ~(SCSCR_TE | SCSCR_RE); > + serial_port_out(port, SCSCR, scscr); Given that the register contains lots of interrupt enable bits, would it make sense to just write it to 0 to disable everything ? I don't think we need to keep any of the SCSCR bits across shutdown/startup. > spin_unlock_irqrestore(&port->lock, flags); > > sci_free_dma(port);
Hi Laurent, Matsuoka-san, On Sat, Aug 22, 2015 at 1:17 AM, Laurent Pinchart <laurent.pinchart@ideasonboard.com> wrote: > On Friday 21 August 2015 20:25:43 Geert Uytterhoeven wrote: >> Make sure the transmitter and receiver are stopped when shutting down >> the port, to avoid new RX DMA requests to arrive. >> >> Inspired by a patch in the BSP by Koji Matsuoka >> <koji.matsuoka.xm@renesas.com>. >> >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c >> index d8b73e791a554823..0622cafaf1c71cab 100644 >> --- a/drivers/tty/serial/sh-sci.c >> +++ b/drivers/tty/serial/sh-sci.c >> @@ -1820,12 +1820,16 @@ static void sci_shutdown(struct uart_port *port) >> { >> struct sci_port *s = to_sci_port(port); >> unsigned long flags; >> + u16 scscr; >> >> dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); >> >> spin_lock_irqsave(&port->lock, flags); >> sci_stop_rx(port); >> sci_stop_tx(port); >> + scscr = serial_port_in(port, SCSCR); >> + scscr &= ~(SCSCR_TE | SCSCR_RE); >> + serial_port_out(port, SCSCR, scscr); > > Given that the register contains lots of interrupt enable bits, would it make > sense to just write it to 0 to disable everything ? I don't think we need to > keep any of the SCSCR bits across shutdown/startup. I don't know. Actually this patch causes a problem on e.g. armadillo and kzm9g, where serial console output suddenly stops on halt/reboot: | # halt | | Broadcast message from root@armadillo (ttySC1) (Tue Aug 25 14:52:35 2015): | The system is going down for system halt NOW! | INIT: Switching to runlevel: 0 | INIT: Sending process After reverting, it continues again with: | es the TERM signal | [info] Using makefile-style concurrent boot in runlevel 0. | [ ok ] Asking all remaining processes to terminate...done. | [ ok ] All processes ended within 1 seconds...done. | [ ok ] Stopping enhanced syslogd: rsyslogd. | [ ok ] Stopping NFS common utilities: idmapd statd. | rpcbind: rpcbind terminating on signal. Restart with "rpcbind -w" | [ ok ] Stopping rpcbind daemon.... | [....] not deconfiguring network interfaces: network file systems still mounted.[war (warning). | [info] Saving the system clock. | [info] Hardware Clock updated to Tue Aug 25 14:56:18 CEST 2015. | [ ok ] Deactivating swap...done. | [info] Will now halt. | reboot: System halted Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org 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 -- To unsubscribe from this list: send the line "unsubscribe linux-sh" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index d8b73e791a554823..0622cafaf1c71cab 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1820,12 +1820,16 @@ static void sci_shutdown(struct uart_port *port) { struct sci_port *s = to_sci_port(port); unsigned long flags; + u16 scscr; dev_dbg(port->dev, "%s(%d)\n", __func__, port->line); spin_lock_irqsave(&port->lock, flags); sci_stop_rx(port); sci_stop_tx(port); + scscr = serial_port_in(port, SCSCR); + scscr &= ~(SCSCR_TE | SCSCR_RE); + serial_port_out(port, SCSCR, scscr); spin_unlock_irqrestore(&port->lock, flags); sci_free_dma(port);
Make sure the transmitter and receiver are stopped when shutting down the port, to avoid new RX DMA requests to arrive. Inspired by a patch in the BSP by Koji Matsuoka <koji.matsuoka.xm@renesas.com>. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> --- v3: - No changes, v2: - New. --- drivers/tty/serial/sh-sci.c | 4 ++++ 1 file changed, 4 insertions(+)