1 files changed, 42 insertions, 0 deletions
diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c
new file mode 100644
index 00000000..13e37e2d
--- /dev/null
+++ b/drivers/of/of_pci.c
@@ -0,0 +1,42 @@
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/of.h>
+#include <linux/of_pci.h>
+#include <asm/prom.h>
+
+static inline int __of_pci_pci_compare(struct device_node *node,
+				       unsigned int devfn)
+{
+	unsigned int size;
+	const __be32 *reg = of_get_property(node, "reg", &size);
+
+	if (!reg || size < 5 * sizeof(__be32))
+		return 0;
+	return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
+}
+
+struct device_node *of_pci_find_child_device(struct device_node *parent,
+					     unsigned int devfn)
+{
+	struct device_node *node, *node2;
+
+	for_each_child_of_node(parent, node) {
+		if (__of_pci_pci_compare(node, devfn))
+			return node;
+		/*
+		 * Some OFs create a parent node "multifunc-device" as
+		 * a fake root for all functions of a multi-function
+		 * device we go down them as well.
+		 */
+		if (!strcmp(node->name, "multifunc-device")) {
+			for_each_child_of_node(node, node2) {
+				if (__of_pci_pci_compare(node2, devfn)) {
+					of_node_put(node);
+					return node2;
+				}
+			}
+		}
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(of_pci_find_child_device);