Re: [PATCH] tty: serial: atmel: add earlycon support

[Michael Walle]

Hi,

Am 2022-02-17 10:12, schrieb Claudiu.Beznea@xxxxxxxxxxxxx:
> On 16.02.2022 18:18, Michael Walle wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know 
> > the content is safe
> >
> > Add early console support which relies on the bootloader for the
> > initialization of the UART.
> > Please note, that the compatibles are taken from at91-usart MFD
> > driver.
> >
> > Signed-off-by: Michael Walle <michael@xxxxxxxx>
> > ---
> >  drivers/tty/serial/atmel_serial.c | 24 ++++++++++++++++++++++++
> >  1 file changed, 24 insertions(+)
> >
> > diff --git a/drivers/tty/serial/atmel_serial.c 
> > b/drivers/tty/serial/atmel_serial.c
> > index 2d09a89974a2..50fc6d51ff0d 100644
> > --- a/drivers/tty/serial/atmel_serial.c
> > +++ b/drivers/tty/serial/atmel_serial.c
> > @@ -2673,6 +2673,30 @@ static struct console atmel_console = {
> >         .data           = &atmel_uart,
> >  };
> >
> > +static void atmel_serial_early_write(struct console *con, const char 
> > *s,
> > +                                    unsigned int n)
> > +{
> > +       struct earlycon_device *dev = con->data;
> > +
> > +       uart_console_write(&dev->port, s, n, atmel_console_putchar);
> > +}
> > +
> > +static int __init atmel_early_console_setup(struct earlycon_device 
> > *device,
> > +                                           const char *options)
> > +{
> > +       if (!device->port.membase)
> > +               return -ENODEV;
> > +
> > +       device->con->write = atmel_serial_early_write;
> > +
> > +       return 0;
> > +}
> > +
> > +OF_EARLYCON_DECLARE(atmelserial, "atmel,at91rm9200-usart",
> > +                   atmel_early_console_setup);
> > +OF_EARLYCON_DECLARE(atmelserial, "atmel,at91sam9260-usart",
>
>
> For consistency with the rest of the naming in this file could you name 
> it
> atmel_serial?

Sure, I don't have an opinion on that. It's done both ways:
omap-serial.c:OF_EARLYCON_DECLARE(omapserial, "ti,omap2-uart", 
early_omap_serial_setup);
bcm63xx_uart.c:OF_EARLYCON_DECLARE(bcm63xx_uart, "brcm,bcm6345-uart", 
bcm_early_console_setup);
...

> Also, it would be good to select SERIAL_EARLYCON in Kconfig to have it
> available also for production w/o changing defconfigs.

Ahh, missed that these are enabled for all the other Kconfig symbols.
Will add it to SERIAL_ATMEL_CONSOLE.

-michael