e1000e: alternate MAC address support

Port alternate MAC address support from the sourceforge
e1000 driver to the upstream e1000e driver.

Signed-off-by: Bill Hayes <bill.hayes@hp.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/e1000e/lib.c b/drivers/net/e1000e/lib.c
index 0bdeca3..16f35fa 100644
--- a/drivers/net/e1000e/lib.c
+++ b/drivers/net/e1000e/lib.c
@@ -2059,9 +2059,44 @@
 {
 	s32 ret_val;
 	u16 offset, nvm_data, i;
+	u16 mac_addr_offset = 0;
+
+	if (hw->mac.type == e1000_82571) {
+		/* Check for an alternate MAC address.  An alternate MAC
+		 * address can be setup by pre-boot software and must be
+		 * treated like a permanent address and must override the
+		 * actual permanent MAC address. */
+		ret_val = e1000_read_nvm(hw, NVM_ALT_MAC_ADDR_PTR, 1,
+						&mac_addr_offset);
+		if (ret_val) {
+			hw_dbg(hw, "NVM Read Error\n");
+			return ret_val;
+		}
+		if (mac_addr_offset == 0xFFFF)
+			mac_addr_offset = 0;
+
+		if (mac_addr_offset) {
+			if (hw->bus.func == E1000_FUNC_1)
+				mac_addr_offset += ETH_ALEN/sizeof(u16);
+
+			/* make sure we have a valid mac address here
+			 * before using it */
+			ret_val = e1000_read_nvm(hw, mac_addr_offset, 1,
+						 &nvm_data);
+			if (ret_val) {
+				hw_dbg(hw, "NVM Read Error\n");
+				return ret_val;
+			}
+			if (nvm_data & 0x0001)
+				mac_addr_offset = 0;
+		}
+
+		if (mac_addr_offset)
+			hw->dev_spec.e82571.alt_mac_addr_is_present = 1;
+	}
 
 	for (i = 0; i < ETH_ALEN; i += 2) {
-		offset = i >> 1;
+		offset = mac_addr_offset + (i >> 1);
 		ret_val = e1000_read_nvm(hw, offset, 1, &nvm_data);
 		if (ret_val) {
 			hw_dbg(hw, "NVM Read Error\n");
@@ -2072,7 +2107,7 @@
 	}
 
 	/* Flip last bit of mac address if we're on second port */
-	if (hw->bus.func == E1000_FUNC_1)
+	if (!mac_addr_offset && hw->bus.func == E1000_FUNC_1)
 		hw->mac.perm_addr[5] ^= 1;
 
 	for (i = 0; i < ETH_ALEN; i++)