[PATCH v2 5/6] serial: Call flush() before changing baudrate

[Pali Rohár]

On Thursday 11 August 2022 08:47:53 Simon Glass wrote:
> On Thu, 11 Aug 2022 at 06:39, Pali Rohár <pali at kernel.org> wrote:
> >
> > Changing baudrate is sensitive operation. To ensure that U-Boot messages
> 
> is a sensitive
> 
> > printed before changing baudrate are not lost, call new U-Boot console
> > flush() function.
> >
> > Signed-off-by: Pali Rohár <pali at kernel.org>
> > ---
> >  cmd/load.c                     | 5 +++++
> >  drivers/serial/serial-uclass.c | 1 +
> >  drivers/serial/serial.c        | 1 +
> >  3 files changed, 7 insertions(+)
> >
> > diff --git a/cmd/load.c b/cmd/load.c
> > index e44ae0d56b75..5c4f34781d45 100644
> > --- a/cmd/load.c
> > +++ b/cmd/load.c
> > @@ -83,6 +83,7 @@ static int do_load_serial(struct cmd_tbl *cmdtp, int flag, int argc,
> >                 printf("## Switch baudrate to %d bps and press ENTER ...\n",
> >                         load_baudrate);
> >                 udelay(50000);
> > +               flush();
> >                 gd->baudrate = load_baudrate;
> >                 serial_setbrg();
> >                 udelay(50000);
> > @@ -126,6 +127,7 @@ static int do_load_serial(struct cmd_tbl *cmdtp, int flag, int argc,
> >                 printf("## Switch baudrate to %d bps and press ESC ...\n",
> >                         current_baudrate);
> >                 udelay(50000);
> > +               flush();
> >                 gd->baudrate = current_baudrate;
> >                 serial_setbrg();
> >                 udelay(50000);
> > @@ -317,6 +319,7 @@ int do_save_serial(struct cmd_tbl *cmdtp, int flag, int argc,
> >                 printf("## Switch baudrate to %d bps and press ESC ...\n",
> >                         (int)current_baudrate);
> >                 udelay(50000);
> > +               flush();
> >                 gd->baudrate = current_baudrate;
> >                 serial_setbrg();
> >                 udelay(50000);
> > @@ -471,6 +474,7 @@ static int do_load_serial_bin(struct cmd_tbl *cmdtp, int flag, int argc,
> >                 printf("## Switch baudrate to %d bps and press ENTER ...\n",
> >                         load_baudrate);
> >                 udelay(50000);
> > +               flush();
> >                 gd->baudrate = load_baudrate;
> >                 serial_setbrg();
> >                 udelay(50000);
> > @@ -533,6 +537,7 @@ static int do_load_serial_bin(struct cmd_tbl *cmdtp, int flag, int argc,
> >                 printf("## Switch baudrate to %d bps and press ESC ...\n",
> >                         current_baudrate);
> >                 udelay(50000);
> > +               flush();
> >                 gd->baudrate = current_baudrate;
> >                 serial_setbrg();
> >                 udelay(50000);
> > diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
> > index 4e32270d4660..0f6860d9100e 100644
> > --- a/drivers/serial/serial-uclass.c
> > +++ b/drivers/serial/serial-uclass.c
> > @@ -527,6 +527,7 @@ static int on_baudrate(const char *name, const char *value, enum env_op op,
> >                         printf("## Switch baudrate to %d bps and press ENTER ...\n",
> >                                baudrate);
> >                         udelay(50000);
> > +                       flush();
> >                 }
> >
> >                 gd->baudrate = baudrate;
> > diff --git a/drivers/serial/serial.c b/drivers/serial/serial.c
> > index 6cdbb89841c1..4b525b644928 100644
> > --- a/drivers/serial/serial.c
> > +++ b/drivers/serial/serial.c
> > @@ -81,6 +81,7 @@ static int on_baudrate(const char *name, const char *value, enum env_op op,
> >                         printf("## Switch baudrate to %d"
> >                                 " bps and press ENTER ...\n", baudrate);
> >                         udelay(50000);
> > +                       flush();
> 
> Please don't implement new features in legacy code.

Sorry, I do not know what is the legacy code in this spaghetti monster.

> >                 }
> >
> >                 gd->baudrate = baudrate;
> > --
> > 2.20.1
> >
> 
> Regards,
> SImon