[PATCH] drivers: serial: Make sure we really return a serial device

[Simon Glass]

Hi Mark,

On Sat, 5 Feb 2022 at 16:10, Mark Kettenis <kettenis at openbsd.org> wrote:
>
> The stdout-path property in the device tree does not necessarily
> point at a serial device. The code that binds the device if it
> isn't marked to be bound before relocation does not check whether
> the device really is a serial device. So check that its uclass is
> UCLASS_SERIAL before probing it.
>
> Signed-off-by: Mark Kettenis <kettenis at openbsd.org>
> ---
>  drivers/serial/serial-uclass.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

This would be better as an assert() to avoid code bloat. Under what
circumstances was this wrong?

>
> diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
> index 96a1cb65ba..931a90bdbd 100644
> --- a/drivers/serial/serial-uclass.c
> +++ b/drivers/serial/serial-uclass.c
> @@ -66,7 +66,8 @@ static int serial_check_stdout(const void *blob, struct udevice **devp)
>          */
>         if (node > 0 && !lists_bind_fdt(gd->dm_root, offset_to_ofnode(node),
>                                         devp, NULL, false)) {
> -               if (!device_probe(*devp))
> +               if (device_get_uclass_id(*devp) == UCLASS_SERIAL &&
> +                   !device_probe(*devp))
>                         return 0;
>         }
>
> --
> 2.34.1
>

Regards,
Simon