[PATCH v5 3/5] ACPI / processor: Introduce map_gic_id() to get apic id from MADT or _MAT method
From: Sudeep Holla <hidden>
Date: 2014-02-19 14:33:19
Also in:
linux-acpi, lkml
Hi Hanjun, On 18/02/14 16:23, Hanjun Guo wrote:
quoted hunk ↗ jump to hunk
Get apic id from MADT or _MAT method is not implemented on arm/arm64, and ACPI 5.0 introduces GIC Structure for it, so this patch introduces map_gic_id() to get apic id followed the ACPI 5.0 spec. Signed-off-by: Hanjun Guo <redacted> --- drivers/acpi/processor_core.c | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+)diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c index 4dcf776..d316d9b 100644 --- a/drivers/acpi/processor_core.c +++ b/drivers/acpi/processor_core.c@@ -71,6 +71,27 @@ static int map_lsapic_id(struct acpi_subtable_header *entry, return 0; } +static int map_gic_id(struct acpi_subtable_header *entry, + int device_declaration, u32 acpi_id, int *apic_id) +{ + struct acpi_madt_generic_interrupt *gic = + (struct acpi_madt_generic_interrupt *)entry; + + if (!(gic->flags & ACPI_MADT_ENABLED)) + return -ENODEV; + + /* In the GIC interrupt model, logical processors are + * required to have a Processor Device object in the DSDT, + * so we should check device_declaration here + */ + if (device_declaration && (gic->uid == acpi_id)) { + *apic_id = gic->gic_id;
I have mentioned this earlier, it's not clear yet to me how does this work ?
It needs more clarity in the form of comment here at-least as the ACPIv5.0 is
also not so clear or explicit on how to handle this.
Here you are expecting gic->uid = acpi_id which is fine, while acpi_map_cpuid
matches apic_id with cpu_physical_id(which must be MPIDR in ARM{32,64}). The
latter imposes restriction that gic->gic_id has to be MPIDR. Does that mean we
are imposing restriction on GIC ID to be MPIDR ? If so please document it here
and please explain the reason behind that choice.
I would expect _UID to be MPIDR rather than GIC ID but you may have some reasons
for this choice.
Regards,
Sudeep