Add of_pci_dma_configure() to allow updating the dma configuration
of the pci device using the configuration from DT of the parent of
the root bridge device.
Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx>
---
drivers/of/of_pci.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_pci.h | 12 ++++++++
2 files changed, 85 insertions(+)
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
index 88471d3..6d43f59 100644
--- a/drivers/of/of_pci.c
+++ b/drivers/of/of_pci.c
@@ -229,6 +229,79 @@ parse_failed:
return err;
}
EXPORT_SYMBOL_GPL(of_pci_get_host_bridge_resources);
+
+/**
+ * of_get_pci_root_bridge_parent - Helper function to get the OF node of
+ * the root bridge's parent
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * This function will traverse the bus up to the root bus starting with
+ * the child and return the of node ptr to bridge device's parent device.
+ */
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev)
+{
+ struct pci_bus *bus = dev->bus;
+ struct device *bridge;
+
+ while (!pci_is_root_bus(bus))
+ bus = bus->parent;
+ bridge = bus->bridge;
+
+ return bridge->parent->of_node;
+}
+EXPORT_SYMBOL_GPL(of_get_pci_root_bridge_parent);
+
+/**
+ * of_pci_dma_configure - Setup DMA configuration
+ * @dev: ptr to pci_dev struct of the pci device
+ *
+ * Try to get PCI devices's DMA configuration from DT and update it
+ * accordingly. This is similar to of_dma_configure() in of/platform.c
+ */
+void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+ struct device *dev = &pci_dev->dev;
+ u64 dma_addr, paddr, size;
+ struct device_node *parent_np;
+ unsigned long offset;
+ bool coherent;
+ int ret;
+
+ parent_np = of_get_pci_root_bridge_parent(pci_dev);
+
+ if (parent_np) {
+ /*
+ * Set default dma-mask to 32 bit. Drivers are expected to setup
+ * the correct supported dma_mask.
+ */
+ dev->coherent_dma_mask = DMA_BIT_MASK(32);
+
+ /*
+ * Set it to coherent_dma_mask by default if the architecture
+ * code has not set it.
+ */
+ if (!dev->dma_mask)
+ dev->dma_mask = &dev->coherent_dma_mask;
+
+ ret = of_dma_get_range(parent_np, &dma_addr, &paddr, &size);
+ if (ret < 0) {
+ dma_addr = offset = 0;
+ size = dev->coherent_dma_mask + 1;
+ } else {
+ offset = PFN_DOWN(paddr - dma_addr);
+ dev_dbg(dev, "dma_pfn_offset(%#08lx)\n", offset);
+ }
+ dev->dma_pfn_offset = offset;
+
+ coherent = of_dma_is_coherent(parent_np);
+ dev_dbg(dev, "device is%sdma coherent\n",
+ coherent ? " " : " not ");
+
+ arch_setup_dma_ops(dev, dma_addr, size, NULL, coherent);
+ }
+}
+EXPORT_SYMBOL_GPL(of_pci_dma_configure);
+
#endif /* CONFIG_OF_ADDRESS */
#ifdef CONFIG_PCI_MSI
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index ce0e5ab..0465a2a 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -16,6 +16,8 @@ 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);
+struct device_node *of_get_pci_root_bridge_parent(struct pci_dev *dev);
+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)
{
@@ -50,6 +52,16 @@ of_get_pci_domain_nr(struct device_node *node)
{
return -1;
}
+
+static inline struct device_node
+*of_get_pci_root_bridge_parent(struct pci_dev *dev)
+{
+ return NULL;
+}
+
+static inline void of_pci_dma_configure(struct pci_dev *pci_dev)
+{
+}
#endif
#if defined(CONFIG_OF_ADDRESS)
--
1.7.9.5
--
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