Re: [PATCH 1/2] arm/arm64: ACPI: Introduce CONFIG_ACPI_MUST_HAVE_CCA

Suravee Suthikulpanit
2015-04-29T14:31:20Z

On 04/29/2015 09:04 AM, Catalin Marinas wrote:
> On Wed, Apr 29, 2015 at 08:44:08AM -0500, Suravee Suthikulpanit wrote:
>> From ACPIv6 (http://www.uefi.org/sites/default/files/resources/ACPI_6.0.pdf),
>> section 6.2.17 _CCA states that ARM platforms require ACPI _CCA object to be
>> specified for DMA-cabpable devices. This patch introduces ACPI_MUST_HAVE_CCA
>> in arm and arm64 Kconfig to specify such requirement.
>>
>> Note that when _CCA is required, if it is missing in the DSDT. ACPI driver
>> will default to setting up devices as non-coherent.
>>
>> Signed-off-by: Mark Salter <msalter@redhat.com>
>> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
>> ---
>> arch/arm/Kconfig | 1 +
>> arch/arm64/Kconfig | 1 +
>> drivers/acpi/Kconfig | 3 +++
>> 3 files changed, 5 insertions(+)
>>
>> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
>> index 45df48b..2a0d036 100644
>> --- a/arch/arm/Kconfig
>> +++ b/arch/arm/Kconfig
>> @@ -1,6 +1,7 @@
>> config ARM
>> bool
>> default y
>> + select ACPI_MUST_HAVE_CCA if ACPI
>> select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
>> select ARCH_HAS_ELF_RANDOMIZE
>> select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>
> Any plans for ACPI on 32-bit ARM?
>

Not that I am aware, but I could be totally wrong. The reason I am
adding this here for 32-bit ARM is because the ACPI spec mentioned this.

If you think this is not necessary until we introduce ACPI for ARM32, it
can be removed.

Thanks,

Suravee