On Thu, Mar 24, 2016 at 1:51 PM, Aleksey Makarov
[off-list ref] 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.

Thanks,
Rafael