net: DM9000: Add support for byte EEPROM access

Given many versions of ethtool's reluctance to do anything other than
byte accesses to the EEPROM interface, it is easier to update the driver
to support byte accesses so that all the ethtool versions that have been
observed in Debian can write the EEPROM.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Reviewed-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/dm9000.c

@@ -535,21 +535,35 @@ static int dm9000_set_eeprom(struct net_device *dev,
 	board_info_t *dm = to_dm9000_board(dev);
 	int offset = ee->offset;
 	int len = ee->len;
-	int i;
+	int done;
 
 	/* EEPROM access is aligned to two bytes */
 
-	if ((len & 1) != 0 || (offset & 1) != 0)
-		return -EINVAL;
-
 	if (dm->flags & DM9000_PLATF_NO_EEPROM)
 		return -ENOENT;
 
 	if (ee->magic != DM_EEPROM_MAGIC)
 		return -EINVAL;
 
-	for (i = 0; i < len; i += 2)
-		dm9000_write_eeprom(dm, (offset + i) / 2, data + i);
+	while (len > 0) {
+		if (len & 1 || offset & 1) {
+			int which = offset & 1;
+			u8 tmp[2];
+
+			dm9000_read_eeprom(dm, offset / 2, tmp);
+			tmp[which] = *data;
+			dm9000_write_eeprom(dm, offset / 2, tmp);
+
+			done = 1;
+		} else {
+			dm9000_write_eeprom(dm, offset / 2, data);
+			done = 2;
+		}
+
+		data += done;
+		offset += done;
+		len -= done;
+	}
 
 	return 0;
 }