Re: [PATCH v3 13/17] ARM64 / ACPI: Add GICv2 specific ACPI boot support

Hanjun Guo
2014-09-03T11:17:45Z

>>>>>> +
>>>>>> +#ifdef CONFIG_ACPI
>>>>>> +#define ACPI_MAX_GIC_CPU_INTERFACE_ENTRIES 65535
>>>>> With GICv2? I doubt it.
>>>> I will create macro for each GIC driver:
>>>> #define ACPI_MAX_GICV2_CPU_INTERFACE_ENTRIES 8
>>>> #define ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES 65535
>>> Where do you get this value (ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES) from?
>> This value is for max processors entries in MADT, and we will use it to scan MADT
>> for SMP/GIC Init, I just make it big enough for GICv3/4. since ACPI core will stop
>> scan MADT if the real numbers of processors entries are reached no matter
>> how big ACPI_MAX_GICV3_CPU_INTERFACE_ENTRIES is, I think we can just
>> define a number big enough then it will work (x86 and ia64 did the same thing).
> Also, with GICv3++, there is no such thing as a memory-mapped CPU
> interface anymore. What you get is a bunch of redistributors (one per
> CPU). I assume what you have here actually describe the redistributors,
> and its name should reflect that.

As Sudeep said, it is not to link to GIC architecture, so I think we can keep
it stick with ACPI spec, in ACPI spec, it called "GICC structure" (section 5.2.12.14
in ACPI 5.1), so we can name it as ACPI_MAX_GICC_STRUCTURE_ENTRIES no matter
GICv2 or GICv3/4 (with GICv2, it may have more than 8 entries with some disabled
ones, will no more than 8 enabled entries).

What do you think?

Thanks
Hanjun