[PATCH AUTOSEL 4.9 64/90] serial: uartps: Wait for tx_empty in console setup

[Naresh Kamboju]

On Tue, 29 Sep 2020 at 01:41, Naresh Kamboju <naresh.kamboju at linaro.org> wrote:
>
> On Fri, 18 Sep 2020 at 07:55, Sasha Levin <sashal at kernel.org> wrote:
> >
> > From: Raviteja Narayanam <raviteja.narayanam at xilinx.com>
> >
> > [ Upstream commit 42e11948ddf68b9f799cad8c0ddeab0a39da33e8 ]
> >
> > On some platforms, the log is corrupted while console is being
> > registered. It is observed that when set_termios is called, there
> > are still some bytes in the FIFO to be transmitted.
> >
> > So, wait for tx_empty inside cdns_uart_console_setup before calling
> > set_termios.
> >
> > Signed-off-by: Raviteja Narayanam <raviteja.narayanam at xilinx.com>
> > Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta at xilinx.com>
> > Link: https://lore.kernel.org/r/1586413563-29125-2-git-send-email-raviteja.narayanam@xilinx.com
> > Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> > Signed-off-by: Sasha Levin <sashal at kernel.org>
>
> stable rc 4.9 arm64 build broken.

and stable rc 4.9 arm build broken.

>
> drivers/tty/serial/xilinx_uartps.c: In function 'cdns_uart_console_setup':
> drivers/tty/serial/xilinx_uartps.c:1286:40: error: 'TX_TIMEOUT'
> undeclared (first use in this function); did you mean 'ETIMEDOUT'?
>   time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
>                                         ^~~~~~~~~~
>                                         ETIMEDOUT
> drivers/tty/serial/xilinx_uartps.c:1286:40: note: each undeclared
> identifier is reported only once for each function it appears in
>   CC      drivers/usb/core/port.o
> scripts/Makefile.build:304: recipe for target
> 'drivers/tty/serial/xilinx_uartps.o' failed
> make[5]: *** [drivers/tty/serial/xilinx_uartps.o] Error 1
>
> Reported-by: Naresh Kamboju <naresh.kamboju at linaro.org>
>
> full test log link,
> https://ci.linaro.org/view/lkft/job/openembedded-lkft-linux-stable-rc-4.9/DISTRO=lkft,MACHINE=hikey,label=docker-lkft/996/consoleText
>
>
> > ---
> >  drivers/tty/serial/xilinx_uartps.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
> > index eb61a07fcbbc3..07ea71a611678 100644
> > --- a/drivers/tty/serial/xilinx_uartps.c
> > +++ b/drivers/tty/serial/xilinx_uartps.c
> > @@ -1268,6 +1268,7 @@ static int cdns_uart_console_setup(struct console *co, char *options)
> >         int bits = 8;
> >         int parity = 'n';
> >         int flow = 'n';
> > +       unsigned long time_out;
> >
> >         if (co->index < 0 || co->index >= CDNS_UART_NR_PORTS)
> >                 return -EINVAL;
> > @@ -1281,6 +1282,13 @@ static int cdns_uart_console_setup(struct console *co, char *options)
> >         if (options)
> >                 uart_parse_options(options, &baud, &parity, &bits, &flow);
> >
> > +       /* Wait for tx_empty before setting up the console */
> > +       time_out = jiffies + usecs_to_jiffies(TX_TIMEOUT);
> > +
> > +       while (time_before(jiffies, time_out) &&
> > +              cdns_uart_tx_empty(port) != TIOCSER_TEMT)
> > +               cpu_relax();
> > +
> >         return uart_set_options(port, co, baud, parity, bits, flow);
> >  }
> >
> > --
> > 2.25.1
> >
>
>
> --
> Linaro LKFT
> https://lkft.linaro.org