Commit b84f196d authored by Suthikulpanit, Suravee's avatar Suthikulpanit, Suravee Committed by Rafael J. Wysocki
Browse files

ACPI: Adding DMA Attribute APIs for ACPI Device 



Adding acpi_get_dma_attr() to query DMA attributes of ACPI devices.
It returns the enum dev_dma_attr, which communicates DMA information
more clearly. This API replaces the acpi_check_dma(), which will be
removed in subsequent patch.

This patch also provides a convenient function, acpi_dma_supported(),
to check DMA support of the specified ACPI device.

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 1b9863c6

drivers/acpi/scan.c

+42 −0
Original line number Diff line number Diff line
@@ -1308,6 +1308,48 @@ void acpi_free_pnp_ids(struct acpi_device_pnp *pnp) 
	kfree(pnp->unique_id);

}



/**

 * acpi_dma_supported - Check DMA support for the specified device.

 * @adev: The pointer to acpi device

 *

 * Return false if DMA is not supported. Otherwise, return true

 */

bool acpi_dma_supported(struct acpi_device *adev)

{

	if (!adev)

		return false;



	if (adev->flags.cca_seen)

		return true;



	/*

	* Per ACPI 6.0 sec 6.2.17, assume devices can do cache-coherent

	* DMA on "Intel platforms".  Presumably that includes all x86 and

	* ia64, and other arches will set CONFIG_ACPI_CCA_REQUIRED=y.

	*/

	if (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED))

		return true;



	return false;

}



/**

 * acpi_get_dma_attr - Check the supported DMA attr for the specified device.

 * @adev: The pointer to acpi device

 *

 * Return enum dev_dma_attr.

 */

enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)

{

	if (!acpi_dma_supported(adev))

		return DEV_DMA_NOT_SUPPORTED;



	if (adev->flags.coherent_dma)

		return DEV_DMA_COHERENT;

	else

		return DEV_DMA_NON_COHERENT;

}



static void acpi_init_coherency(struct acpi_device *adev)

{

	unsigned long long cca = 0;

include/acpi/acpi_bus.h

+3 −0
Original line number Diff line number Diff line
@@ -596,6 +596,9 @@ struct acpi_pci_root { 


/* helper */



bool acpi_dma_supported(struct acpi_device *adev);

enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev);



struct acpi_device *acpi_find_child_device(struct acpi_device *parent,

					   u64 address, bool check_children);

int acpi_is_root_bridge(acpi_handle);

include/linux/acpi.h

+10 −0
Original line number Diff line number Diff line
@@ -579,6 +579,16 @@ static inline bool acpi_check_dma(struct acpi_device *adev, bool *coherent) 
	return false;

}



static inline bool acpi_dma_supported(struct acpi_device *adev)

{

	return false;

}



static inline enum dev_dma_attr acpi_get_dma_attr(struct acpi_device *adev)

{

	return DEV_DMA_NOT_SUPPORTED;

}



#define ACPI_PTR(_ptr)	(NULL)



#endif	/* !CONFIG_ACPI */

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