Re: [PATCH v6 0/5] ACPI: parse the SPCR table

From: Rafael J. Wysocki
Date: Thu Mar 24 2016 - 09:16:29 EST

On Thu, Mar 24, 2016 at 1:51 PM, Aleksey Makarov
<aleksey.makarov@xxxxxxxxxx> wrote:
> 'ARM Server Base Boot Requirements' [1] mentions SPCR (Serial Port
> Console Redirection Table) [2] as a mandatory ACPI table that
> specifies the configuration of serial console.
> Move "earlycon" early_param handling to earlycon.c to parse this option once
> Patch "ACPI: add definitions of DBG2 subtypes" is required for the next patch.
> ACPI maintainers said that they had got it for the next release of ACPICA,
> but it has not appeared in linux-next yet.

It will. Patches containing it have just been posted.

> Parse SPCR table, setup earlycon and add register specified console.
> Enable parsing this table on ARM64. Earlycon should be set up
> as early as possible. ACPI boot tables are mapped in
> arch/arm64/kernel/acpi.c:acpi_boot_table_init() called from setup_arch()
> and that's where we parse spcr. So it has to be opted-in per-arch.
> Implement console_match() for pl011.
> Based on the work by Leif Lindholm [3]
> Thanks to Peter Hurley for explaining how this should work.
> Should be applied to next-20160324.
> Tested on QEMU. SPCR support is included in QEMU's ARM mach-virt
> since 2.4 release.

Honestly, I'm not sure why I'm regarded as the right maintainer to send this to.

The only patch here touching generic ACPI code is [3/5] (the [2/5] is
going in through ACPICA) and the rest is all about ARM64 AFAICS. Why
don't you send it to the ARM64 maintainers instead?

I'll have some comments on [3/5], I'll send them later today or tomorrow.