eth: fwnode: add a helper for loading netdev->dev_addr

Commit 406f42fa ("net-next: When a bond have a massive amount
of VLANs...") introduced a rbtree for faster Ethernet address look
up. To maintain netdev->dev_addr in this tree we need to make all
the writes to it got through appropriate helpers.

There is a handful of drivers which pass netdev->dev_addr as
the destination buffer to device_get_mac_address(). Add a helper
which takes a dev pointer instead, so it can call an appropriate
helper.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/etherdevice.h

@@ -32,6 +32,7 @@ int eth_platform_get_mac_address(struct device *dev, u8 *mac_addr);
 unsigned char *arch_get_platform_mac_address(void);
 int nvmem_get_mac_address(struct device *dev, void *addrbuf);
 int device_get_mac_address(struct device *dev, char *addr);
+int device_get_ethdev_address(struct device *dev, struct net_device *netdev);
 int fwnode_get_mac_address(struct fwnode_handle *fwnode, char *addr);
 
 u32 eth_get_headlen(const struct net_device *dev, const void *data, u32 len);

include/linux/property.h

@@ -15,6 +15,7 @@
 #include <linux/types.h>
 
 struct device;
+struct net_device;
 
 enum dev_prop_type {
 	DEV_PROP_U8,

net/ethernet/eth.c

@@ -617,3 +617,23 @@ int device_get_mac_address(struct device *dev, char *addr)
 	return fwnode_get_mac_address(dev_fwnode(dev), addr);
 }
 EXPORT_SYMBOL(device_get_mac_address);
+
+/**
+ * device_get_ethdev_address - Set netdev's MAC address from a given device
+ * @dev:	Pointer to the device
+ * @netdev:	Pointer to netdev to write the address to
+ *
+ * Wrapper around device_get_mac_address() which writes the address
+ * directly to netdev->dev_addr.
+ */
+int device_get_ethdev_address(struct device *dev, struct net_device *netdev)
+{
+	u8 addr[ETH_ALEN];
+	int ret;
+
+	ret = device_get_mac_address(dev, addr);
+	if (!ret)
+		eth_hw_addr_set(netdev, addr);
+	return ret;
+}
+EXPORT_SYMBOL(device_get_ethdev_address);