[PATCH] pci: acpi: Generic function for setting up PCI device DMA coherency

[Suravee Suthikulpanit]

This patch refactors of_pci_dma_configure() into a more generic
pci_dma_configure(), which can be reused by non-OF code.
Then, it 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 at amd.com>
CC: Bjorn Helgaas <bhelgaas at google.com>
CC: Catalin Marinas <catalin.marinas at arm.com>
CC: Will Deacon <will.deacon at arm.com>
CC: Rafael J. Wysocki <rjw at rjwysocki.net>
CC: Rob Herring <robh+dt at kernel.org>
CC: Murali Karicheri <m-karicheri2 at ti.com>
---
Note: According to the ACPI spec, the _CCA attribute is required
      for ARM64. Therefore, this patch is a pre-req for ACPI PCI
      support for ARM64 which is currently in development.

      Also, this should not affect other architectures since
      if CCA is not required, the default value is coherent.
      Please see include/acpi/acpi_bus.h: acpi_check_dma() and
      drivers/acpi/scan.c: acpi_init_coherency() for more information

 drivers/of/of_pci.c    | 20 --------------------
 drivers/pci/probe.c    | 35 +++++++++++++++++++++++++++++++++--
 include/linux/of_pci.h |  3 ---
 3 files changed, 33 insertions(+), 25 deletions(-)

diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 5751dc5..b66ee4e 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -117,26 +117,6 @@ int of_get_pci_domain_nr(struct device_node *node)
 }
 EXPORT_SYMBOL_GPL(of_get_pci_domain_nr);
 
-/**
- * of_pci_dma_configure - Setup DMA configuration
- * @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).
- */
-void of_pci_dma_configure(struct pci_dev *pci_dev)
-{
-	struct device *dev = &pci_dev->dev;
-	struct device *bridge = pci_get_host_bridge_device(pci_dev);
-
-	if (!bridge->parent)
-		return;
-
-	of_dma_configure(dev, bridge->parent->of_node);
-	pci_put_host_bridge_device(bridge);
-}
-EXPORT_SYMBOL_GPL(of_pci_dma_configure);
-
 #if defined(CONFIG_OF_ADDRESS)
 /**
  * of_pci_get_host_bridge_resources - Parse PCI host bridge resources from DT
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index cefd636..e2fcd3b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -6,12 +6,14 @@
 #include <linux/delay.h>
 #include <linux/init.h>
 #include <linux/pci.h>
-#include <linux/of_pci.h>
+#include <linux/of_device.h>
 #include <linux/pci_hotplug.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/cpumask.h>
 #include <linux/pci-aspm.h>
+#include <linux/acpi.h>
+#include <linux/property.h>
 #include <asm-generic/pci-bridge.h>
 #include "pci.h"
 
@@ -1544,6 +1546,35 @@ static void pci_init_capabilities(struct pci_dev *dev)
 	pci_enable_acs(dev);
 }
 
+/**
+ * pci_dma_configure - Setup DMA configuration
+ * @pci_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 or ACPI node of host bridge's parent (if any).
+ */
+static void pci_dma_configure(struct pci_dev *pci_dev)
+{
+	struct device *dev = &pci_dev->dev;
+	struct device *bridge = pci_get_host_bridge_device(pci_dev);
+	struct acpi_device *adev;
+	bool coherent;
+
+	if (has_acpi_companion(bridge)) {
+		adev = to_acpi_node(bridge->fwnode);
+		if (acpi_check_dma(adev, &coherent))
+			arch_setup_dma_ops(dev, 0, 0, NULL, coherent);
+	} else {
+		struct device *host = bridge->parent;
+		if (!host)
+			return;
+
+		of_dma_configure(dev, host->of_node);
+	}
+
+	pci_put_host_bridge_device(bridge);
+}
+
 void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 {
 	int ret;
@@ -1557,7 +1588,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	dev->dev.dma_mask = &dev->dma_mask;
 	dev->dev.dma_parms = &dev->dma_parms;
 	dev->dev.coherent_dma_mask = 0xffffffffull;
-	of_pci_dma_configure(dev);
+	pci_dma_configure(dev);
 
 	pci_set_dma_max_seg_size(dev, 65536);
 	pci_set_dma_seg_boundary(dev, 0xffffffff);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 29fd3fe..ce0e5ab 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -16,7 +16,6 @@ int of_pci_get_devfn(struct device_node *np);
 int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin);
 int of_pci_parse_bus_range(struct device_node *node, struct resource *res);
 int of_get_pci_domain_nr(struct device_node *node);
-void of_pci_dma_configure(struct pci_dev *pci_dev);
 #else
 static inline int of_irq_parse_pci(const struct pci_dev *pdev, struct of_phandle_args *out_irq)
 {
@@ -51,8 +50,6 @@ of_get_pci_domain_nr(struct device_node *node)
 {
 	return -1;
 }
-
-static inline void of_pci_dma_configure(struct pci_dev *pci_dev) { }
 #endif
 
 #if defined(CONFIG_OF_ADDRESS)
-- 
2.1.0