Add support for reading and writing mac addresses to or from ID EEPROM.

Added code for reading and writing Mac addresses to/from ID EEPROM(0x57).
With attached patch, we can use command "mac/mac read/mac save/"
to read and write EEPROM under u-boot prompt.

U-boot will calculate the checksum of EEPROM while bootup,
if it is right, then u-boot will check whether the mac address
of eTSEC0/1/2/3 is availalbe (non-zero).

If there is mac address availabe in EEPROM, u-boot will use it,
otherewise, u-boot will use the mac address defined in
MPC8641HPCN.h. This matches the requirement to set unique mac address
for each TSEC port.

Signed-off-by: Haiying Wang <haiying.wang@freescale.com>
Signed-off-by: York Sun <yorksun@freescale.com>
diff --git a/common/cmd_mac.c b/common/cmd_mac.c
new file mode 100644
index 0000000..0add432
--- /dev/null
+++ b/common/cmd_mac.c
@@ -0,0 +1,66 @@
+/*
+ * Copyright 2006 Freescale Semiconductor
+ * York Sun (yorksun@freescale.com)
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <command.h>
+
+#ifdef CFG_ID_EEPROM
+
+extern int do_mac(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]);
+
+U_BOOT_CMD(
+	mac, 3, 1,  do_mac,
+	"mac     - display and program the system ID and MAC addresses in EEPROM\n",
+	"[read|save|id|num|errata|date|ports|0|1|2|3|4|5|6|7]\n"
+	"read\n"
+	"    - show content of mac\n"
+	"mac save\n"
+	"    - save to the EEPROM\n"
+	"mac id\n"
+	"    - program system id\n"
+	"mac num\n"
+	"    - program system serial number\n"
+	"mac errata\n"
+	"    - program errata data\n"
+	"mac date\n"
+	"    - program data date\n"
+	"mac ports\n"
+	"    - program the number of ports\n"
+	"mac 0\n"
+	"    - program the MAC address for port 0\n"
+	"mac 1\n"
+	"    - program the MAC address for port 1\n"
+	"mac 2\n"
+	"    - program the MAC address for port 2\n"
+	"mac 3\n"
+	"    - program the MAC address for port 3\n"
+	"mac 4\n"
+	"    - program the MAC address for port 4\n"
+	"mac 5\n"
+	"    - program the MAC address for port 5\n"
+	"mac 6\n"
+	"    - program the MAC address for port 6\n"
+	"mac 7\n"
+	"    - program the MAC address for port 7\n"
+);
+#endif /* CFG_ID_EEPROM */