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SubjectRe: [PATCH v2 09/18] ACPI / processor: Make it possible to get CPU hardware ID via GICC
On 2014-8-20 22:56, Catalin Marinas wrote:
> On Tue, Aug 19, 2014 at 09:37:34AM +0100, Hanjun Guo wrote:
>> On 2014-8-18 22:27, Catalin Marinas wrote:
>>> On Mon, Aug 04, 2014 at 04:28:16PM +0100, Hanjun Guo wrote:
>>>> diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
>>>> index e32321c..4007313 100644
>>>> --- a/drivers/acpi/processor_core.c
>>>> +++ b/drivers/acpi/processor_core.c
>>>> @@ -64,6 +64,38 @@ static int map_lsapic_id(struct acpi_subtable_header *entry,
>>>> return 0;
>>>> }
>>>>
>>>> +/*
>>>> + * On ARM platform, MPIDR value is the hardware ID as apic ID
>>>> + * on Intel platforms
>>>> + */
>>>> +static int map_gicc_mpidr(struct acpi_subtable_header *entry,
>>>> + int device_declaration, u32 acpi_id, int *mpidr)
>>>> +{
>>>> + struct acpi_madt_generic_interrupt *gicc =
>>>> + container_of(entry, struct acpi_madt_generic_interrupt, header);
>>>> +
>>>> + if (!(gicc->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 && (gicc->uid == acpi_id)) {
>>>> + /*
>>>> + * Only bits [0:7] Aff0, bits [8:15] Aff1, bits [16:23] Aff2
>>>> + * and bits [32:39] Aff3 are meaningful, so pack the Affx
>>>> + * fields into a single 32 bit identifier to accommodate the
>>>> + * acpi processor drivers.
>>>> + */
>>>> + *mpidr = ((gicc->arm_mpidr & 0xff00000000) >> 8)
>>>> + | gicc->arm_mpidr;
>>>
>>> You can use pack_mpidr_into_32_bits().
>>
>> processor_core.c will be used by x86 and ia64 too, it will cause
>> compile error on !ARM64 platforms.
>
> Oh. So we do we have an ARM-specific function in core ACPI code?

Yes, GICC is ARM-specific, but all the mapping functions (get apic_id/mpidr
via acpi_id in MADT) including x86/ia64 are all there, so it's better to put it
here to keep consistency.

Thanks
Hanjun


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