On Monday, May 11, 2015 05:16:27 PM Catalin Marinas wrote:
On Fri, May 08, 2015 at 10:53:59PM +0200, Rafael J. Wysocki wrote:
On Thursday, May 07, 2015 07:37:12 PM Suravee Suthikulpanit wrote:
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index ab2cbb5..7822149 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -54,6 +54,12 @@ config ACPI_GENERIC_GSI config ACPI_SYSTEM_POWER_STATES_SUPPORT bool +config ACPI_CCA_REQUIRED
- bool
+config ARM64_SUPPORT_ACPI_CCA_ZERO
Hmm. I guess the Arnd's idea what to simply use CONFIG_ARM64 directly instead of adding this new option.
I agree.
+static inline bool acpi_dma_is_supported(struct acpi_device *adev) +{
- /**
* Currently, we mainly support _CCA=1 (i.e. is_coherent=1)* This should be equivalent to specifyig dma-coherent for* a device in OF.** For the case when _CCA=0 (i.e. is_coherent=0 && cca_seen=1),* we would rely on arch-specific cache maintenance for* non-coherence DMA operations if architecture specifies* _XXX_SUPPORT_CCA_ZERO. Otherwise, we do not support* DMA on this device and fallback to arch-specific default* handling.** For the case when _CCA is missing (i.e. cca_seen=0) but* platform specifies ACPI_CCA_REQUIRED, we do not support DMA,* and fallback to arch-specific default handling.*/- return adev && (adev->flags.is_coherent ||
(adev->flags.cca_seen &&IS_ENABLED(CONFIG_ARM64_SUPPORT_ACPI_CCA_ZERO)));So what exactly would be wrong with using IS_ENABLED(CONFIG_ARM64) here?
I'm not sure I follow why we need to check for ARM64 here at all. Can we not just have something like:
return adev && (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) || adev->flags.cca_seen)
If _CCA returns 0 on non-ARM64, DMA is not supported for this device, so in that case the function should return 'false' while the above check will make it return 'true'.