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

Catalin Marinas
2015-04-29T14:42:41Z

On Wed, Apr 29, 2015 at 09:31:03AM -0500, Suravee Suthikulpanit wrote:
>
>
> 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.

I think it should be removed (as long as ACPI cannot be selected on
arm32).

--
Catalin