ACPI: Honor ACPI _CCA attribute setting

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@arm.com>
Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index e234725eadc7..8df990520304 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;