[PATCH V4 1/8] acpi: Honor ACPI _CCA attribute setting

[Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>]

From: Jeremy Linton <jeremy.linton@arm.com>

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>
CC: Bjorn Helgaas <bhelgaas@google.com>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Will Deacon <will.deacon@arm.com>
CC: Rafael J. Wysocki <rjw@rjwysocki.net>
---
 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 5ba8fb6..5a42204 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -395,7 +395,7 @@ 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,
@@ -403,7 +403,8 @@ 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;
-- 
2.1.0