PCI: ACPI: Add support for PCI device DMA coherency

This patch adds support for setting up PCI device DMA coherency from
ACPI _CCA object that should normally be specified in the DSDT node
of its PCI host bridge.

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>

1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index d35f83d80b15..064078e11017 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/cpumask.h>
 #include <linux/pci-aspm.h>
+#include <linux/acpi.h>
 #include <asm-generic/pci-bridge.h>
 #include "pci.h"
 
@@ -1639,7 +1640,7 @@ static void pci_set_msi_domain(struct pci_dev *dev)
  * @dev: ptr to pci_dev struct of the PCI device
  *
  * Function to update PCI devices's DMA configuration using the same
- * info from the OF node of host bridge's parent (if any).
+ * info from the OF node or ACPI node of host bridge's parent (if any).
  */
 static void pci_dma_configure(struct pci_dev *dev)
 {
@@ -1648,6 +1649,15 @@ static void pci_dma_configure(struct pci_dev *dev)
         if (IS_ENABLED(CONFIG_OF) && dev->dev.of_node) {
                 if (bridge->parent)
                         of_dma_configure(&dev->dev, bridge->parent->of_node);
+        } else if (has_acpi_companion(bridge)) {
+                struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
+                enum dev_dma_attr attr = acpi_get_dma_attr(adev);
+
+                if (attr == DEV_DMA_NOT_SUPPORTED)
+                        dev_warn(&dev->dev, "DMA not supported.\n");
+                else
+                        arch_setup_dma_ops(&dev->dev, 0, 0, NULL,
+                                           attr == DEV_DMA_COHERENT);
         }
 
         pci_put_host_bridge_device(bridge);