diff options
| author | Suthikulpanit, Suravee <Suravee.Suthikulpanit@amd.com> | 2015-10-28 15:50:48 -0700 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-11-07 01:29:21 +0100 |
| commit | b84f196d963c3159329f72ca1913b08679004a43 (patch) | |
| tree | a017e66514453e0fdc5489076877d1a02a5e568a | |
| parent | 1b9863c6aa56d92126ec0d5c42eae25df52b7ca1 (diff) | |
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>
| -rw-r--r-- | drivers/acpi/scan.c | 42 | ||||
| -rw-r--r-- | include/acpi/acpi_bus.h | 3 | ||||
| -rw-r--r-- | include/linux/acpi.h | 10 |
3 files changed, 55 insertions, 0 deletions
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index d1ce377db3e9..ed3d76fadccf 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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; diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index 8df990520304..e56e6520edce 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -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); diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 496265b0f527..292af3b69ede 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -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 */ |