tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * OF helpers for network devices.
3 *
4 * This file is released under the GPLv2
5 *
6 * Initially copied out of arch/powerpc/kernel/prom_parse.c
7 */
8#include <linux/etherdevice.h>
9#include <linux/kernel.h>
10#include <linux/of_net.h>
11
12/**
13 * Search the device tree for the best MAC address to use. 'mac-address' is
14 * checked first, because that is supposed to contain to "most recent" MAC
15 * address. If that isn't set, then 'local-mac-address' is checked next,
16 * because that is the default address. If that isn't set, then the obsolete
17 * 'address' is checked, just in case we're using an old device tree.
18 *
19 * Note that the 'address' property is supposed to contain a virtual address of
20 * the register set, but some DTS files have redefined that property to be the
21 * MAC address.
22 *
23 * All-zero MAC addresses are rejected, because those could be properties that
24 * exist in the device tree, but were not set by U-Boot. For example, the
25 * DTS could define 'mac-address' and 'local-mac-address', with zero MAC
26 * addresses. Some older U-Boots only initialized 'local-mac-address'. In
27 * this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
28 * but is all zeros.
29*/
30const void *of_get_mac_address(struct device_node *np)
31{
32 struct property *pp;
33
34 pp = of_find_property(np, "mac-address", NULL);
35 if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
36 return pp->value;
37
38 pp = of_find_property(np, "local-mac-address", NULL);
39 if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
40 return pp->value;
41
42 pp = of_find_property(np, "address", NULL);
43 if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
44 return pp->value;
45
46 return NULL;
47}
48EXPORT_SYMBOL(of_get_mac_address);