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

[Catalin Marinas]

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@xxxxxxxxxx>
> >>Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> >>---
> >>  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
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