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: 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>
This commit is contained in:
Suthikulpanit, Suravee 2015-10-28 15:50:48 -07:00 committed by Rafael J. Wysocki
parent 1b9863c6aa
commit b84f196d96
3 changed files with 55 additions and 0 deletions

View file

@ -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;

View file

@ -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);

View file

@ -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 */