Check version register of the OTP

The version of register 0 and 1 must be greater or equal to 1,
otherwise do not attempt to read any data from the OTP.

Signed-off-by: Francois Berder <[email protected]>

Author: francois-berder

board/imgtec/pistachio_bub/Makefile

@@ -21,4 +21,5 @@ obj-y				+= cmd_scratchpad.o
 endif
 ifdef CONFIG_WINBOND_OTP
 obj-y				+= fdt.o
+obj-y				+= otp.o
 endif

board/imgtec/pistachio_bub/fdt.c

@@ -10,10 +10,7 @@
 #if defined(CONFIG_OF_LIBFDT) && defined(CONFIG_OF_BOARD_SETUP)
 
 #include <winbond-otp.h>
-
-#define WIFI_STA_MAC_ADDRESS_OFFSET	0x1003
-#define WIFI_AP_MAC_ADDRESS_OFFSET	0x1009
-#define DCXO_OFFSET			0x2003
+#include "otp.h"
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -69,7 +66,13 @@ static void fixup_wifi_calibration(void *blob, int node)
 
 int ft_board_setup(void *blob, bd_t *bd)
 {
-	int node = fdt_path_offset(blob, "wifi0");
+	int node;
+
+	if (check_otp_version(VERSION_REG0_OFFSET)
+	||  check_otp_version(VERSION_REG1_OFFSET))
+		return -1;
+
+	node = fdt_path_offset(blob, "wifi0");
 	if (node < 0) {
 		printf("WARNING: can't find wifi0 alias\n");
 		return -1;

board/imgtec/pistachio_bub/otp.c

@@ -0,0 +1,27 @@
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Francois Berder <[email protected]>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <winbond-otp.h>
+#include "otp.h"
+
+int check_otp_version(loff_t offset)
+{
+	u_char version;
+
+	if (read_otp_data(offset, sizeof(version), (char *)&version)) {
+		printf("WARNING: Could not read register version from OTP.\n");
+		return -1;
+	}
+
+	if (version < 1) {
+		printf("WARNING: Unknown version in OTP.\n");
+		return -1;
+	}
+
+	return 0;
+}

board/imgtec/pistachio_bub/otp.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2016 Imagination Technologies
+ * Author: Francois Berder <[email protected]>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _OTP_H
+#define _OTP_H
+
+#define MAC_ADDR_LEN 6
+
+#ifdef CONFIG_WINBOND_OTP
+
+#include <linux/types.h>
+
+#define VERSION_REG0_OFFSET		0x1002
+#define VERSION_REG1_OFFSET		0x2002
+#define WIFI_STA_MAC_ADDRESS_OFFSET	0x1003
+#define WIFI_AP_MAC_ADDRESS_OFFSET	0x1009
+#define ETH_MAC_ADDRESS_OFFSET		0x1015
+#define DCXO_OFFSET			0x2003
+
+/*
+ * check_otp_version: Check version register from OTP
+ * @offset: Offset of the register in the OTP.
+ *
+ * returns:
+ *	0 if the version is equal to 1
+ *	-1 otherwise
+ */
+int check_otp_version(loff_t offset);
+
+#endif
+
+#endif

board/imgtec/pistachio_bub/pistachio.c

@@ -23,8 +23,8 @@
 #include <tpm.h>
 #include <winbond-otp.h>
 #include "mfio.h"
+#include "otp.h"
 
-#define ETH_MAC_ADDRESS_OFFSET          0x1015 /* Ethernet MAC address offset */
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -129,7 +129,8 @@ int board_eth_init(bd_t *bs)
 	eth_getenv_enetaddr("ethaddr", mac_addr);
 
 #ifdef CONFIG_WINBOND_OTP
-	if (!is_valid_ethaddr(mac_addr)) {
+	if (!is_valid_ethaddr(mac_addr)
+	&&  !check_otp_version(VERSION_REG0_OFFSET)) {
 		if (!read_otp_data(ETH_MAC_ADDRESS_OFFSET, MAC_ADDR_LEN,
 				   (char *)mac_addr)
 		&&  is_valid_ethaddr(mac_addr))

include/winbond-otp.h

@@ -8,8 +8,6 @@
 #ifndef WINBOND_OTP_H
 #define WINBOND_OTP_H
 
-#define MAC_ADDR_LEN 6
-
 int read_otp_data(loff_t from, size_t len, char *data);
 
 #endif