2019-10-08 23:11:31

by Paul Walmsley

[permalink] [raw]
Subject: [PATCH] Documentation: admin-guide: add earlycon documentation for the sifive serial driver


Document earlycon usage for the SiFive serial port driver in the same
fashion as for the other serial port IP blocks, since the SiFive
serial port driver supports it.

Signed-off-by: Paul Walmsley <[email protected]>
Reported-by: Andreas Schwab <[email protected]>
Cc: Christoph Hellwig <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c7ac2f3ac99f..90becb00221b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1106,6 +1106,12 @@
address must be provided, and the serial port must
already be setup and configured.

+ sifive,<addr>
+ Start an early, polled-mode console on a SiFive
+ serial port at the specified address. The port must
+ already be setup and configured. Options are not
+ yet supported.
+
earlyprintk= [X86,SH,ARM,M68k,S390]
earlyprintk=vga
earlyprintk=sclp
--
2.23.0


2019-10-09 06:57:40

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH] Documentation: admin-guide: add earlycon documentation for the sifive serial driver

Hi Paul,

On Wed, Oct 9, 2019 at 1:09 AM Paul Walmsley <[email protected]> wrote:
> Document earlycon usage for the SiFive serial port driver in the same
> fashion as for the other serial port IP blocks, since the SiFive
> serial port driver supports it.
>
> Signed-off-by: Paul Walmsley <[email protected]>
> Reported-by: Andreas Schwab <[email protected]>
> Cc: Christoph Hellwig <[email protected]>

Thanks for your patch!

Why do you need this?
I believe risc-v is DT-only, so if chosen/stdout-path is set up, just
passing "earlycon" (without any options) should work.

> ---
> Documentation/admin-guide/kernel-parameters.txt | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index c7ac2f3ac99f..90becb00221b 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1106,6 +1106,12 @@
> address must be provided, and the serial port must
> already be setup and configured.
>
> + sifive,<addr>
> + Start an early, polled-mode console on a SiFive
> + serial port at the specified address. The port must
> + already be setup and configured. Options are not
> + yet supported.
> +
> earlyprintk= [X86,SH,ARM,M68k,S390]
> earlyprintk=vga
> earlyprintk=sclp

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

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

2019-10-09 10:08:31

by Andreas Schwab

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Subject: Re: [PATCH] Documentation: admin-guide: add earlycon documentation for the sifive serial driver

On Okt 09 2019, Geert Uytterhoeven <[email protected]> wrote:

> I believe risc-v is DT-only, so if chosen/stdout-path is set up

If. Currently, it isn't.

Andreas.

--
Andreas Schwab, SUSE Labs, [email protected]
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE 1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

2019-10-09 10:57:04

by Geert Uytterhoeven

[permalink] [raw]
Subject: Re: [PATCH] Documentation: admin-guide: add earlycon documentation for the sifive serial driver

Hi Andreas,

On Wed, Oct 9, 2019 at 12:06 PM Andreas Schwab <[email protected]> wrote:
> On Okt 09 2019, Geert Uytterhoeven <[email protected]> wrote:
> > I believe risc-v is DT-only, so if chosen/stdout-path is set up
>
> If. Currently, it isn't.

IC. So isn't it better to fix that, instead of pointing people to more obscure
legacy solutions?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]

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

2019-10-09 14:31:51

by Paul Walmsley

[permalink] [raw]
Subject: Re: [PATCH] Documentation: admin-guide: add earlycon documentation for the sifive serial driver

Hi Geert,

On Wed, 9 Oct 2019, Geert Uytterhoeven wrote:

> On Wed, Oct 9, 2019 at 12:06 PM Andreas Schwab <[email protected]> wrote:
> > On Okt 09 2019, Geert Uytterhoeven <[email protected]> wrote:
> > > I believe risc-v is DT-only, so if chosen/stdout-path is set up
> >
> > If. Currently, it isn't.
>
> IC. So isn't it better to fix that, instead of pointing people to more obscure
> legacy solutions?

There's nothing that's RISC-V specific about the SiFive serial IP or
its driver. So the issue of whether RISC-V is DT-only or not probably
shouldn't impact whether we document that the SiFive serial driver
supports earlycon.

best regards,

- Paul