fsl: obsolete NXID v0 EEPROMs, automatically upgrade them to NXID v1

The NXID EEPROM format comes in two versions, v0 and v1.  The only
difference is in the number of MAC addresses that can be stored.  NXID v0
supports eight addresses, and NXID v1 supports 23.

Rather than allow a board to choose which version to support, NXID v0 is
now considered deprecated.  The EEPROM code is updated to support only
NXID v1, but it can still read EEPROMs formatted with v0.  In these cases,
the EEPROM data is loaded and the CRC is verified, but the data is stored
into a v1 data structure.  If the EEPROM data is written back, it is
written in v1 format.  This allows existing v0-formatted EEPROMs to
continue providing MAC addresses, but any changes to the data will force
an upgrade to the v1 format, while retaining all data.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

board/freescale/common/sys_eeprom.c

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006, 2008-2009 Freescale Semiconductor
+ * Copyright 2006, 2008-2009, 2011 Freescale Semiconductor
  * York Sun (yorksun@freescale.com)
  * Haiying Wang (haiying.wang@freescale.com)
  * Timur Tabi (timur@freescale.com)
@@ -34,12 +34,6 @@
 #endif
 
 #ifdef CONFIG_SYS_I2C_EEPROM_NXID
-#define MAX_NUM_PORTS	8
-#define NXID_VERSION	0
-#endif
-
-#ifdef CONFIG_SYS_I2C_EEPROM_NXID_1
-#define CONFIG_SYS_I2C_EEPROM_NXID
 #define MAX_NUM_PORTS	23
 #define NXID_VERSION	1
 #endif
@@ -428,11 +422,16 @@ int do_mac(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  * This ensures that any user-saved variables are never overwritten.
  *
  * This function must be called after relocation.
+ *
+ * For NXID v1 EEPROMs, we support loading and up-converting the older NXID v0
+ * format.  In a v0 EEPROM, there are only eight MAC addresses and the CRC is
+ * located at a different offset.
  */
 int mac_read_from_eeprom(void)
 {
 	unsigned int i;
-	u32 crc;
+	u32 crc, crc_offset = offsetof(struct eeprom, crc);
+	u32 *crcp; /* Pointer to the CRC in the data read from the EEPROM */
 
 	puts("EEPROM: ");
 
@@ -447,12 +446,32 @@ int mac_read_from_eeprom(void)
 		return -1;
 	}
 
-	crc = crc32(0, (void *)&e, sizeof(e) - 4);
-	if (crc != be32_to_cpu(e.crc)) {
+#ifdef CONFIG_SYS_I2C_EEPROM_NXID
+	/*
+	 * If we've read an NXID v0 EEPROM, then we need to set the CRC offset
+	 * to where it is in v0.
+	 */
+	if (e.version == 0)
+		crc_offset = 0x72;
+#endif
+
+	crc = crc32(0, (void *)&e, crc_offset);
+	crcp = (void *)&e + crc_offset;
+	if (crc != be32_to_cpu(*crcp)) {
 		printf("CRC mismatch (%08x != %08x)\n", crc, be32_to_cpu(e.crc));
 		return -1;
 	}
 
+#ifdef CONFIG_SYS_I2C_EEPROM_NXID
+	/*
+	 * MAC address #9 in v1 occupies the same position as the CRC in v0.
+	 * Erase it so that it's not mistaken for a MAC address.  We'll
+	 * update the CRC later.
+	 */
+	if (e.version == 0)
+		memset(e.mac[8], 0xff, 6);
+#endif
+
 	for (i = 0; i < min(e.mac_count, MAX_NUM_PORTS); i++) {
 		if (memcmp(&e.mac[i], "\0\0\0\0\0\0", 6) &&
 		    memcmp(&e.mac[i], "\xFF\xFF\xFF\xFF\xFF\xFF", 6)) {
@@ -482,6 +501,17 @@ int mac_read_from_eeprom(void)
 	printf("%c%c%c%c\n", e.id[0], e.id[1], e.id[2], e.id[3]);
 #endif
 
+#ifdef CONFIG_SYS_I2C_EEPROM_NXID
+	/*
+	 * Now we need to upconvert the data into v1 format.  We do this last so
+	 * that at boot time, U-Boot will still say "NXID v0".
+	 */
+	if (e.version == 0) {
+		e.version = NXID_VERSION;
+		update_crc();
+	}
+#endif
+
 	return 0;
 }