Kernels booting on RISC-V can specify "earlycon" with no options on
the Linux command line, and the generic DT earlycon support will query
the "chosen/stdout-path" property (if present) to determine which
early console device to use. Document this appropriately in the
admin-guide.
Signed-off-by: Paul Walmsley <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Andreas Schwab <[email protected]>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index c7ac2f3ac99f..011fee969ece 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -990,6 +990,10 @@
[X86] When used with no options the early console is
determined by the ACPI SPCR table.
+ [RISCV] When used with no options, the early
+ console is determined by the stdout-path
+ property in the device tree's chosen node.
+
cdns,<addr>[,options]
Start an early, polled-mode console on a Cadence
(xuartps) serial port at the specified address. Only
--
2.23.0
On Wed, Oct 9, 2019 at 9:53 PM Paul Walmsley <[email protected]> wrote:
> Kernels booting on RISC-V can specify "earlycon" with no options on
> the Linux command line, and the generic DT earlycon support will query
> the "chosen/stdout-path" property (if present) to determine which
> early console device to use. Document this appropriately in the
> admin-guide.
>
> Signed-off-by: Paul Walmsley <[email protected]>
Reviewed-by: Geert Uytterhoeven <[email protected]>
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
On Thu, 10 Oct 2019 09:10:18 +0200
Geert Uytterhoeven <[email protected]> wrote:
> On Wed, Oct 9, 2019 at 9:53 PM Paul Walmsley <[email protected]> wrote:
> > Kernels booting on RISC-V can specify "earlycon" with no options on
> > the Linux command line, and the generic DT earlycon support will query
> > the "chosen/stdout-path" property (if present) to determine which
> > early console device to use. Document this appropriately in the
> > admin-guide.
> >
> > Signed-off-by: Paul Walmsley <[email protected]>
>
> Reviewed-by: Geert Uytterhoeven <[email protected]>
Applied, thanks.
jon
On Wed, Oct 09, 2019 at 12:53:50PM -0700, Paul Walmsley wrote:
>
> Kernels booting on RISC-V can specify "earlycon" with no options on
> the Linux command line, and the generic DT earlycon support will query
> the "chosen/stdout-path" property (if present) to determine which
> early console device to use. Document this appropriately in the
> admin-guide.
Jon already applied a patch from me removing the bogus arch restrictions
on the earlycon without arguments documentation, so this should not
be required.
Jon,
can you please revert this? The paragraph above this addition already
describes the riscv case perfecty well with my previous patch:
earlycon= [KNL] Output early console device and options.
When used with no options, the early console is
determined by stdout-path property in device tree's
chosen node or the ACPI SPCR table if supported by
the platform.
[RISCV] When used with no options, the early
console is determined by the stdout-path
property in the device tree's chosen node.
Hi Jon,
On Fri, 8 Nov 2019, Christoph Hellwig wrote:
> can you please revert this? The paragraph above this addition already
> describes the riscv case perfecty well with my previous patch:
>
> earlycon= [KNL] Output early console device and options.
>
> When used with no options, the early console is
> determined by stdout-path property in device tree's
> chosen node or the ACPI SPCR table if supported by
> the platform.
>
> [RISCV] When used with no options, the early
> console is determined by the stdout-path
> property in the device tree's chosen node.
I support reverting the RISCV section, now that Christoph's more general
change has gone in.
- Paul
On Mon, 11 Nov 2019 17:30:13 +0000 (UTC)
Paul Walmsley <[email protected]> wrote:
> On Fri, 8 Nov 2019, Christoph Hellwig wrote:
>
> > can you please revert this? The paragraph above this addition already
> > describes the riscv case perfecty well with my previous patch:
> >
> > earlycon= [KNL] Output early console device and options.
> >
> > When used with no options, the early console is
> > determined by stdout-path property in device tree's
> > chosen node or the ACPI SPCR table if supported by
> > the platform.
> >
> > [RISCV] When used with no options, the early
> > console is determined by the stdout-path
> > property in the device tree's chosen node.
>
> I support reverting the RISCV section, now that Christoph's more general
> change has gone in.
OK, the patch has been reverted.
Thanks,
jon