[PATCH v3] ARM64: kernel: implement ACPI parking protocol

[Loc Ho]

Hi Lorenzo,

On Tue, Jan 26, 2016 at 3:10 AM, Lorenzo Pieralisi
<lorenzo.pieralisi at arm.com> wrote:
> The SBBR and ACPI specifications allow ACPI based systems that do not
> implement PSCI (eg systems with no EL3) to boot through the ACPI parking
> protocol specification[1].
>
> This patch implements the ACPI parking protocol CPU operations, and adds
> code that eases parsing the parking protocol data structures to the
> ARM64 SMP initializion carried out at the same time as cpus enumeration.
>
> To wake-up the CPUs from the parked state, this patch implements a
> wakeup IPI for ARM64 (ie arch_send_wakeup_ipi_mask()) that mirrors the
> ARM one, so that a specific IPI is sent for wake-up purpose in order
> to distinguish it from other IPI sources.
>
> Given the current ACPI MADT parsing API, the patch implements a glue
> layer that helps passing MADT GICC data structure from SMP initialization
> code to the parking protocol implementation somewhat overriding the CPU
> operations interfaces. This to avoid creating a completely trasparent
> DT/ACPI CPU operations layer that would require creating opaque
> structure handling for CPUs data (DT represents CPU through DT nodes, ACPI
> through static MADT table entries), which seems overkill given that ACPI
> on ARM64 mandates only two booting protocols (PSCI and parking protocol),
> so there is no need for further protocol additions.
>
> Based on the original work by Mark Salter <msalter at redhat.com>
>
> [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docx
>
> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
> Cc: Will Deacon <will.deacon at arm.com>
> Cc: Hanjun Guo <hanjun.guo at linaro.org>
> Cc: Loc Ho <lho at apm.com>
> Cc: Sudeep Holla <sudeep.holla at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Mark Rutland <mark.rutland at arm.com>
> Cc: Mark Salter <msalter at redhat.com>
> Cc: Al Stone <ahs3 at redhat.com>

I had tested this with X-Gene Mustang board. It applies cleanly
against 4.5.0-rc1 and detected all CPU's. For those of you want to try
this, you need an FW update if you are using APM Tianocore. Otherwise,
it will stuck in very early booting stage.

Thanks,
Loc