3 files changed, 53 insertions, 0 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index aa675ebd8eb3..e4b93a0a15d2 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -49,6 +49,10 @@ config OF_I2C
         help
           OpenFirmware I2C accessors
 
+config OF_NET
+        depends on NETDEVICES
+        def_bool y
+
 config OF_SPI
         def_tristate SPI
         depends on SPI && !SPARC
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 7888155bea08..3ab21a0a4907 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -6,5 +6,6 @@ obj-$(CONFIG_OF_IRQ)    += irq.o
 obj-$(CONFIG_OF_DEVICE) += device.o platform.o
 obj-$(CONFIG_OF_GPIO)   += gpio.o
 obj-$(CONFIG_OF_I2C)    += of_i2c.o
+obj-$(CONFIG_OF_NET)    += of_net.o
 obj-$(CONFIG_OF_SPI)    += of_spi.o
 obj-$(CONFIG_OF_MDIO)   += of_mdio.o
diff --git a/drivers/of/of_net.c b/drivers/of/of_net.c
new file mode 100644
index 000000000000..86f334a2769c
--- /dev/null
+++ b/drivers/of/of_net.c
@@ -0,0 +1,48 @@
+/*
+ * 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);