1#include <linux/kernel.h>
 2#include <linux/export.h>
 3#include <linux/of.h>
 4#include <linux/of_pci.h>
 5#include <asm/prom.h>
 6
 7static inline int __of_pci_pci_compare(struct device_node *node,
 8				       unsigned int devfn)
 9{
10	unsigned int size;
11	const __be32 *reg = of_get_property(node, "reg", &size);
12
13	if (!reg || size < 5 * sizeof(__be32))
14		return 0;
15	return ((be32_to_cpup(&reg[0]) >> 8) & 0xff) == devfn;
16}
17
18struct device_node *of_pci_find_child_device(struct device_node *parent,
19					     unsigned int devfn)
20{
21	struct device_node *node, *node2;
22
23	for_each_child_of_node(parent, node) {
24		if (__of_pci_pci_compare(node, devfn))
25			return node;
26		/*
27		 * Some OFs create a parent node "multifunc-device" as
28		 * a fake root for all functions of a multi-function
29		 * device we go down them as well.
30		 */
31		if (!strcmp(node->name, "multifunc-device")) {
32			for_each_child_of_node(node, node2) {
33				if (__of_pci_pci_compare(node2, devfn)) {
34					of_node_put(node);
35					return node2;
36				}
37			}
38		}
39	}
40	return NULL;
41}
42EXPORT_SYMBOL_GPL(of_pci_find_child_device);