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

[Hanjun Guo]

On 2015å04æ29æ 22:42, Catalin Marinas wrote:
> 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).

I agree.

Now there is no plan for ARM32 ACPI as I know, ACPI for ARM targets
for ARM64 based enterprise system at now.

Thanks
Hanjun
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