[PATCH V3 1/4] Honor ACPI _CCA attribute setting

From: Suravee Suthikulpanit
Date: Wed Aug 26 2015 - 09:55:12 EST


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 83061ca..7ecb8e4 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -399,7 +399,7 @@ 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,
@@ -407,7 +407,8 @@ 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

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