On Thu, Oct 29, 2015 at 6:50 AM, Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx> wrote:
> From: Jeremy Linton <jeremy.linton@xxxxxxx>
>
> ACPI configurations can now mark devices as noncoherent,
> support that choice.
>
> NOTE: This is required to support USB on ARM Juno Development Board.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> CC: Catalin Marinas <catalin.marinas@xxxxxxx>
> CC: Rob Herring <robh+dt@xxxxxxxxxx>
> CC: Will Deacon <will.deacon@xxxxxxx>
> CC: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> ---
> include/acpi/acpi_bus.h | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index d11eff8..0f131d2 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -407,7 +407,7 @@ static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent)
> * case 1. Do not support and disable DMA.
> * case 2. Support but rely on arch-specific cache maintenance for
> * non-coherence DMA operations.
> - * Currently, we implement case 1 above.
> + * Currently, we implement case 2 above.
> *
> * For the case when _CCA is missing (i.e. cca_seen=0) and
> * platform specifies ACPI_CCA_REQUIRED, we do not support DMA,
> @@ -415,7 +415,8 @@ static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent)
> *
> * See acpi_init_coherency() for more info.
> */
> - if (adev->flags.coherent_dma) {
> + if (adev->flags.coherent_dma ||
> + (adev->flags.cca_seen && IS_ENABLED(CONFIG_ARM64))) {
> ret = true;
> if (coherent)
> *coherent = adev->flags.coherent_dma;
Hi Suravee,
The acpi_check_dma function has been removed in patch 6 of this patch set, why it is still be used
here, am I missing something? If the acpi_check_dma will be used in the future, personally I'd like
to use IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) while not CONFIG_ARM64 macro here, or since _CCA attribute
is arch-specific, it's reasonable to leave the _CCA handling policy to the arch-specific code. For example,
with a link weak function like acpi_arch_check_dma() as a default handling if no arch-specific code
provided, the actual _CCA handling will be implemented in the ARM, Intel or other Arch if required.
Thanks,
Dennis
> --
> 2.1.0
>
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