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

Simon Glass
2022-08-11T14:49:37Z

On Thu, 11 Aug 2022 at 06:39, Pali Rohár <pali@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@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.

> }
>
> gd->baudrate = baudrate;
> --
> 2.20.1
>

Regards,
SImon