Merge branches 'for-4.4/upstream-fixes', 'for-4.5/async-suspend', 'for-4.5/container...

[mirror_ubuntu-artful-kernel.git] / drivers / acpi / scan.c

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index daf9fc8329e64c41817269d0b6c437e3ccb2d1e3..78d5f02a073bb1c9e84beaeaf2f38b6f54125333 100644 (file)
--- 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;