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/*
* OF helpers for network devices.
*
* This file is released under the GPLv2
*
* Initially copied out of arch/powerpc/kernel/prom_parse.c
*/
#include <linux/etherdevice.h>
#include <linux/kernel.h>
#include <linux/of_net.h>
/**
* Search the device tree for the best MAC address to use. 'mac-address' is
* checked first, because that is supposed to contain to "most recent" MAC
* address. If that isn't set, then 'local-mac-address' is checked next,
* because that is the default address. If that isn't set, then the obsolete
* 'address' is checked, just in case we're using an old device tree.
*
* Note that the 'address' property is supposed to contain a virtual address of
* the register set, but some DTS files have redefined that property to be the
* MAC address.
*
* All-zero MAC addresses are rejected, because those could be properties that
* exist in the device tree, but were not set by U-Boot. For example, the
* DTS could define 'mac-address' and 'local-mac-address', with zero MAC
* addresses. Some older U-Boots only initialized 'local-mac-address'. In
* this case, the real MAC is in 'local-mac-address', and 'mac-address' exists
* but is all zeros.
*/
const void *of_get_mac_address(struct device_node *np)
{
struct property *pp;
pp = of_find_property(np, "mac-address", NULL);
if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
return pp->value;
pp = of_find_property(np, "local-mac-address", NULL);
if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
return pp->value;
pp = of_find_property(np, "address", NULL);
if (pp && (pp->length == 6) && is_valid_ether_addr(pp->value))
return pp->value;
return NULL;
}
EXPORT_SYMBOL(of_get_mac_address);
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