1#include <linux/kernel.h>
 2#include <linux/of.h>
 3#include <linux/of_pci.h>
 4#include <asm/prom.h>
 5
 6static inline int __of_pci_pci_compare(struct device_node *node,
 7				       unsigned int devfn)
 8{
 9	unsigned int size;
10	const __be32 *reg = of_get_property(node, "reg", &size);
11
12	if (!reg || size < 5 * sizeof(__be32))
13		return 0;
14	return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
15}
16
17struct device_node *of_pci_find_child_device(struct device_node *parent,
18					     unsigned int devfn)
19{
20	struct device_node *node, *node2;
21
22	for_each_child_of_node(parent, node) {
23		if (__of_pci_pci_compare(node, devfn))
24			return node;
25		/*
26		 * Some OFs create a parent node "multifunc-device" as
27		 * a fake root for all functions of a multi-function
28		 * device we go down them as well.
29		 */
30		if (!strcmp(node->name, "multifunc-device")) {
31			for_each_child_of_node(node, node2) {
32				if (__of_pci_pci_compare(node2, devfn)) {
33					of_node_put(node);
34					return node2;
35				}
36			}
37		}
38	}
39	return NULL;
40}
41EXPORT_SYMBOL_GPL(of_pci_find_child_device);