Merge branch 'acpi-cca'

[linux-2.6-microblaze.git] / drivers / acpi / scan.c

diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index 4bbc8f8..2649a06 100644 (file)
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -11,6 +11,7 @@
 #include <linux/kthread.h>
 #include <linux/dmi.h>
 #include <linux/nls.h>
+#include <linux/dma-mapping.h>
 
 #include <asm/pgtable.h>
 
@@ -2153,6 +2154,39 @@ void acpi_free_pnp_ids(struct acpi_device_pnp *pnp)
        kfree(pnp->unique_id);
 }
 
+static void acpi_init_coherency(struct acpi_device *adev)
+{
+       unsigned long long cca = 0;
+       acpi_status status;
+       struct acpi_device *parent = adev->parent;
+
+       if (parent && parent->flags.cca_seen) {
+               /*
+                * From ACPI spec, OSPM will ignore _CCA if an ancestor
+                * already saw one.
+                */
+               adev->flags.cca_seen = 1;
+               cca = parent->flags.coherent_dma;
+       } else {
+               status = acpi_evaluate_integer(adev->handle, "_CCA",
+                                              NULL, &cca);
+               if (ACPI_SUCCESS(status))
+                       adev->flags.cca_seen = 1;
+               else if (!IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED))
+                       /*
+                        * If architecture does not specify that _CCA is
+                        * required for DMA-able devices (e.g. x86),
+                        * we default to _CCA=1.
+                        */
+                       cca = 1;
+               else
+                       acpi_handle_debug(adev->handle,
+                                         "ACPI device is missing _CCA.\n");
+       }
+
+       adev->flags.coherent_dma = cca;
+}
+
 void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
                             int type, unsigned long long sta)
 {
@@ -2171,6 +2205,7 @@ void acpi_init_device_object(struct acpi_device *device, acpi_handle handle,
        device->flags.visited = false;
        device_initialize(&device->dev);
        dev_set_uevent_suppress(&device->dev, true);
+       acpi_init_coherency(device);
 }
 
 void acpi_device_add_finalize(struct acpi_device *device)