| Message ID | 1654627965-1461-2-git-send-email-quic_vnivarth@quicinc.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] serial: core: Introduce callback for start_rx and do stop_rx in suspend only if this callback implementation is present. | expand |
Hi, On Tue, Jun 7, 2022 at 11:53 AM Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> wrote: > > In suspend sequence there is a need to perform stop_rx during suspend > sequence to prevent any asynchronous data over rx line. However this > can cause problem to drivers which dont do re-start_rx during set_termios. > > Add new callback start_rx and perform stop_rx only when implementation of > start_rx is present. Also add call to start_rx in resume sequence so that > drivers who come across this problem can make use of this framework. > > Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled") > Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> > --- > drivers/tty/serial/serial_core.c | 9 ++++++--- > include/linux/serial_core.h | 1 + > 2 files changed, 7 insertions(+), 3 deletions(-) Reviewed-by: Douglas Anderson <dianders@chromium.org>
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 9a85b41..338ebad 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -2214,11 +2214,12 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport) /* * Nothing to do if the console is not suspending * except stop_rx to prevent any asynchronous data - * over RX line. Re-start_rx, when required, is - * done by set_termios in resume sequence + * over RX line. However ensure that we will be + * able to Re-start_rx later. */ if (!console_suspend_enabled && uart_console(uport)) { - uport->ops->stop_rx(uport); + if (uport->ops->start_rx) + uport->ops->stop_rx(uport); goto unlock; } @@ -2310,6 +2311,8 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *uport) if (console_suspend_enabled) uart_change_pm(state, UART_PM_STATE_ON); uport->ops->set_termios(uport, &termios, NULL); + if (!console_suspend_enabled && uport->ops->start_rx) + uport->ops->start_rx(uport); if (console_suspend_enabled) console_start(uport->cons); } diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index cbd5070..657a0fc 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -45,6 +45,7 @@ struct uart_ops { void (*unthrottle)(struct uart_port *); void (*send_xchar)(struct uart_port *, char ch); void (*stop_rx)(struct uart_port *); + void (*start_rx)(struct uart_port *); void (*enable_ms)(struct uart_port *); void (*break_ctl)(struct uart_port *, int ctl); int (*startup)(struct uart_port *);
In suspend sequence there is a need to perform stop_rx during suspend sequence to prevent any asynchronous data over rx line. However this can cause problem to drivers which dont do re-start_rx during set_termios. Add new callback start_rx and perform stop_rx only when implementation of start_rx is present. Also add call to start_rx in resume sequence so that drivers who come across this problem can make use of this framework. Fixes: c9d2325cdb92 ("serial: core: Do stop_rx in suspend path for console if console_suspend is disabled") Signed-off-by: Vijaya Krishna Nivarthi <quic_vnivarth@quicinc.com> --- drivers/tty/serial/serial_core.c | 9 ++++++--- include/linux/serial_core.h | 1 + 2 files changed, 7 insertions(+), 3 deletions(-)