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Commit d764c21c authored by Jeremy Linton's avatar Jeremy Linton Committed by Rafael J. Wysocki
Browse files

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: default avatarJeremy Linton <jeremy.linton@arm.com>
Signed-off-by: default avatarSuravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Acked-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 5293fea2

include/acpi/acpi_bus.h

+3 −2
Original line number Diff line number Diff line
@@ -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;