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