Hi John,
CC linux-sh (SH-specific code)
CC linux-renesas-soc (JFYI)
On Mon, Nov 7, 2022 at 3:20 PM John Ogness <john.ogness@xxxxxxxxxxxxx> wrote:
> When setting up the early console, the setup() callback of the
> regular console is used. It is called manually before registering
> the early console instead of providing a setup() callback for the
> early console. This is probably because the early setup needs a
> different @options during the early stage.
>
> The issue here is that the setup() callback is called without the
> console_list_lock held and functions such as uart_set_options()
> expect that.
>
> Rather than manually calling the setup() function before registering,
> provide an early console setup() callback that will use the different
> early options. This ensures that the error checking, ordering, and
> locking context when setting up the early console are correct.
>
> Note that technically the current implementation works because it is
> only used in early boot. And since the early console setup is
> performed before registering, it cannot race with anything and thus
> does not need any locking. However, longterm maintenance is easier
> when drivers rely on the subsystem API rather than manually
> implementing steps that could cause breakage in the future.
>
> Signed-off-by: John Ogness <john.ogness@xxxxxxxxxxxxx>
Thanks for your patch!
> --- a/drivers/tty/serial/sh-sci.c
> +++ b/drivers/tty/serial/sh-sci.c
> @@ -3054,15 +3054,26 @@ static struct console serial_console = {
> };
>
> #ifdef CONFIG_SUPERH
> +static char early_serial_buf[32];
> +
> +static int early_serial_console_setup(struct console *co, char *options)
> +{
> + WARN_ON(options);
> + /*
> + * Use @early_serial_buf because @options will always be
> + * NULL at this early stage.
> + */
> + return serial_console_setup(co, early_serial_buf);
> +}
> +
> static struct console early_serial_console = {
> .name = "early_ttySC",
> .write = serial_console_write,
> + .setup = early_serial_console_setup,
> .flags = CON_PRINTBUFFER,
> .index = -1,
> };
>
> -static char early_serial_buf[32];
> -
> static int sci_probe_earlyprintk(struct platform_device *pdev)
> {
> const struct plat_sci_port *cfg = dev_get_platdata(&pdev->dev);
> @@ -3074,8 +3085,6 @@ static int sci_probe_earlyprintk(struct platform_device *pdev)
>
> sci_init_single(pdev, &sci_ports[pdev->id], pdev->id, cfg, true);
>
> - serial_console_setup(&early_serial_console, early_serial_buf);
> -
> if (!strstr(early_serial_buf, "keep"))
> early_serial_console.flags |= CON_BOOT;
>
> --
> 2.30.2
LGTM, so
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
