[PATCH] imx6: ocotp: Add On-Chip OTP registers write support

Uladzimir Bely u.bely at sam-solutions.net
Wed Apr 2 08:30:29 EDT 2014


OCOTP imx6 driver updated and ocotptool command added.
MAC address can be written to PROM. "0" (unprogrammed) bits
of MAC can be replaced with "1" (but not vice versa) only once.

Tested on phytec-phyflex-imx6 board.
Also works on phytec-phycard-imx6 (not yet in barebox).

Signed-off-by: Uladzimir Bely <u.bely at sam-solutions.net>
---
 arch/arm/mach-imx/Kconfig |   8 ++
 arch/arm/mach-imx/ocotp.c | 288 ++++++++++++++++++++++++++++++++++++++++++++++
 commands/Kconfig          |  11 ++
 commands/Makefile         |   1 +
 commands/ocotptool.c      | 150 ++++++++++++++++++++++++
 5 files changed, 458 insertions(+)
 create mode 100644 commands/ocotptool.c

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index b7e7533..3e71815 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -609,6 +609,14 @@ config IMX_OCOTP
 	  only supported functionality is reading the MAC address and assigning
 	  it to an ethernet device.
 
+config IMX_OCOTP_WRITE
+	bool
+	prompt "Enable write support of i.MX6 CPUs OTP fuses"
+	depends on IMX_OCOTP
+	help
+	  This adds support for writing to On-Chip OTP registers.
+
+
 endmenu
 
 endif
diff --git a/arch/arm/mach-imx/ocotp.c b/arch/arm/mach-imx/ocotp.c
index e36b484..0f1735a 100644
--- a/arch/arm/mach-imx/ocotp.c
+++ b/arch/arm/mach-imx/ocotp.c
@@ -26,12 +26,282 @@
 #include <io.h>
 #include <of.h>
 
+#include <linux/clk.h>
+#include <mach/imx6-regs.h>
+
 /*
  * a single MAC address reference has the form
  * <&phandle regoffset>
  */
 #define MAC_ADDRESS_PROPLEN	(2 * sizeof(__be32))
 
+/* OCOTP Registers */
+#define OCOTP_CTRL			(MX6_OCOTP_BASE_ADDR + 0x0000)
+#define OCOTP_CTRL_SET			(MX6_OCOTP_BASE_ADDR + 0x0004)
+#define OCOTP_CTRL_CLR			(MX6_OCOTP_BASE_ADDR + 0x0008)
+#define OCOTP_CTRL_TOG			(MX6_OCOTP_BASE_ADDR + 0x000C)
+#define OCOTP_TIMING			(MX6_OCOTP_BASE_ADDR + 0x0010)
+#define OCOTP_DATA			(MX6_OCOTP_BASE_ADDR + 0x0020)
+#define OCOTP_READ_CTRL			(MX6_OCOTP_BASE_ADDR + 0x0030)
+#define OCOTP_READ_FUSE_DATA		(MX6_OCOTP_BASE_ADDR + 0x0040)
+
+/* OCOTP Registers bit positions and masks */
+#define OCOTP_CTRL_WR_UNLOCK		16
+#define OCOTP_CTRL_WR_UNLOCK_KEY	0x3E77
+#define OCOTP_CTRL_WR_UNLOCK_MASK	0xFFFF0000
+#define OCOTP_CTRL_ADDR			0
+#define OCOTP_CTRL_ADDR_MASK		0x0000007F
+#define OCOTP_CTRL_RELOAD_SHADOWS	10
+#define OCOTP_CTRL_ERROR		9
+#define OCOTP_CTRL_BUSY			8
+
+#define OCOTP_TIMING_STROBE_READ	16
+#define OCOTP_TIMING_STROBE_READ_MASK	0x003F0000
+#define OCOTP_TIMING_RELAX		12
+#define OCOTP_TIMING_RELAX_MASK		0x0000F000
+#define OCOTP_TIMING_STROBE_PROG	0
+#define OCOTP_TIMING_STROBE_PROG_MASK	0x00000FFF
+
+#define OCOTP_READ_CTRL_READ_FUSE	0x00000001
+
+#define BF(value, field)		(((value) << field) & field##_MASK)
+
+/* Other definitions */
+#define IMX6_OTP_ADDR_MAX		0x7F
+#define IMX6_OTP_DATA_ERROR_VAL		0xBADABADA
+
+#define FUSE_REGS_COUNT			(16 * 8)
+#define DEF_RELAX			20
+
+struct ocotp_priv {
+	struct cdev cdev;
+	void __iomem *base;
+	int regsize;
+};
+
+static int imx6_ocotp_wait_busy(u32 flags)
+{
+	int count;
+	u32 cf;
+
+	for (count = 10000; count >= 0; count--) {
+		cf = (1 << OCOTP_CTRL_BUSY) | (1 << OCOTP_CTRL_ERROR) | flags;
+		cf &= readl(OCOTP_CTRL);
+		if (!cf)
+			break;
+	}
+
+	if (count < 0) {
+		printf("ERROR: otp_wait_busy timeout. 0x%X\n", cf);
+		/* Clear ERROR bit, BUSY bit will be cleared by controller */
+		writel(1 << OCOTP_CTRL_ERROR, OCOTP_CTRL_CLR);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int imx6_ocotp_set_timing(void)
+{
+	u32 clk_rate;
+	u32 relax, strobe_read, strobe_prog;
+	u32 timing;
+
+	/* Get clock */
+	clk_rate = clk_get_rate(clk_lookup("ipg"));
+	if (clk_rate == -1) {
+		printf("ERROR: imx6_get_gptclk failed\n");
+		return -1;
+	}
+
+	relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
+	strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
+	strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
+
+	timing = BF(relax, OCOTP_TIMING_RELAX);
+	timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
+	timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
+
+	writel(timing, OCOTP_TIMING);
+
+	return 0;
+}
+
+static int imx6_ocotp_read_prep(void)
+{
+	return  (!imx6_ocotp_set_timing()) ? imx6_ocotp_wait_busy(0) : -1;
+}
+
+static int fuse_read_addr(u32 addr, u32 *pdata)
+{
+	u32 ctrl_reg;
+
+	ctrl_reg = readl(OCOTP_CTRL);
+	ctrl_reg &= ~OCOTP_CTRL_ADDR_MASK;
+	ctrl_reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
+	ctrl_reg |= BF(addr, OCOTP_CTRL_ADDR);
+	writel(ctrl_reg, OCOTP_CTRL);
+
+	writel(OCOTP_READ_CTRL_READ_FUSE, OCOTP_READ_CTRL);
+	if (imx6_ocotp_wait_busy(0))
+		return -1;
+
+	*pdata = readl(OCOTP_READ_FUSE_DATA);
+
+	return 0;
+}
+
+/* Read one u32 to indexed fuse */
+int imx6_ocotp_read_one_u32(u32 index, u32 *pdata)
+{
+	u32 ctrl_reg;
+
+	if (index > IMX6_OTP_ADDR_MAX) {
+		printf("ERROR: invalid address.\n");
+		return -1;
+	}
+	if (imx6_ocotp_read_prep()) {
+		printf("ERROR: read preparation failed\n");
+		return -1;
+	}
+	if (fuse_read_addr(index, pdata)) {
+		printf("ERROR: read failed\n");
+		return -1;
+	}
+	if (*pdata == IMX6_OTP_DATA_ERROR_VAL) {
+		ctrl_reg = readl(OCOTP_CTRL);
+		if (ctrl_reg & (1 << OCOTP_CTRL_ERROR)) {
+			printf("ERROR: read fuse failed\n");
+			return -1;
+		}
+	}
+	return 0;
+}
+
+static ssize_t imx6_ocotp_cdev_read(struct cdev *cdev, void *buf, size_t count,
+		loff_t offset, ulong flags)
+{
+	ulong i;
+	struct device_d *dev = cdev->dev;
+	void __iomem *base;
+	u32		index;
+
+	base = dev_request_mem_region(dev, 0);
+
+	index = offset >> 2;
+	count >>= 2;
+	if (count > (FUSE_REGS_COUNT - index))
+		count = FUSE_REGS_COUNT - index - 1;
+
+	for (i = index; i < (index + count); i++) {
+		imx6_ocotp_read_one_u32(i, buf);
+		buf += 4;
+	}
+	count <<= 2;
+
+	return count;
+}
+
+#ifdef CONFIG_IMX_OCOTP_WRITE
+static int imx6_ocotp_blow_prep(void)
+{
+	return  (!imx6_ocotp_set_timing()) ? imx6_ocotp_wait_busy(0) : -1;
+}
+
+static int imx6_ocotp_blow_post(void)
+{
+	printf("Reloading shadow registers...\n");
+	/* Reload all the shadow registers */
+	writel(1 << OCOTP_CTRL_RELOAD_SHADOWS, OCOTP_CTRL_SET);
+	udelay(1);
+
+	return imx6_ocotp_wait_busy(1 << OCOTP_CTRL_RELOAD_SHADOWS);
+}
+
+static int fuse_blow_addr(u32 addr, u32 value)
+{
+	u32 ctrl_reg;
+
+	/* Control register */
+	ctrl_reg = readl(OCOTP_CTRL);
+	ctrl_reg &= ~OCOTP_CTRL_ADDR_MASK;
+	ctrl_reg |= BF(addr, OCOTP_CTRL_ADDR);
+	ctrl_reg |= BF(OCOTP_CTRL_WR_UNLOCK_KEY, OCOTP_CTRL_WR_UNLOCK);
+	writel(ctrl_reg, OCOTP_CTRL);
+
+	writel(value, OCOTP_DATA);
+	if (imx6_ocotp_wait_busy(0))
+		return -1;
+
+	/* Write postamble */
+	udelay(2000);
+	return 0;
+}
+
+/*
+ * Blow one u32 to indexed fuse
+ */
+int imx6_ocotp_blow_one_u32(u32 index, u32 data, u32 *pfused_value)
+{
+	if (imx6_ocotp_blow_prep()) {
+		printf("ERROR: blow preparation failed\n");
+		return -1;
+	}
+	if (fuse_blow_addr(index, data)) {
+		printf("ERROR: blow fuse failed\n");
+		return -1;
+	}
+	if (imx6_ocotp_blow_post()) {
+		printf("ERROR: blow post operation failed\n");
+		return -1;
+	}
+	if (readl(OCOTP_CTRL) & (1 << OCOTP_CTRL_ERROR)) {
+		printf("ERROR: OTP control\n");
+		return -1;
+	}
+	if (imx6_ocotp_read_one_u32(index, pfused_value)) {
+		printf("ERROR: OTP read\n");
+		return -1;
+	}
+	return 0;
+}
+
+static ssize_t imx6_ocotp_cdev_write(struct cdev *cdev,
+		const void *buf, size_t count,
+		loff_t offset, ulong flags)
+{
+	ulong size, index, i;
+	u32 data, pfuse;
+
+	index = offset >> 2;
+	size = count >> 2;
+
+	if (size > (FUSE_REGS_COUNT - index))
+		size = FUSE_REGS_COUNT - index - 1;
+
+	if (IS_ENABLED(CONFIG_IMX_OCOTP_WRITE)) {
+		for (i = 0; i < size; i++) {
+			int ret;
+
+			memcpy(&data, buf + i * 4, 4);
+			ret = imx6_ocotp_blow_one_u32(index + i, data, &pfuse);
+			if (ret < 0)
+				return ret;
+		}
+	}
+
+	return count;
+}
+#endif
+
+static const struct file_operations imx6_ocotp_ops = {
+	.read	= imx6_ocotp_cdev_read,
+#ifdef CONFIG_IMX_OCOTP_WRITE
+	.write	= imx6_ocotp_cdev_write,
+#endif
+	.lseek	= dev_lseek_default,
+};
+
 static void imx_ocotp_init_dt(struct device_d *dev, void __iomem *base)
 {
 	char mac[6];
@@ -74,10 +344,28 @@ static int imx_ocotp_probe(struct device_d *dev)
 {
 	void __iomem *base;
 
+	int ret = 0;
+	struct ocotp_priv *priv;
+	struct cdev *cdev;
+
 	base = dev_request_mem_region(dev, 0);
 	if (!base)
 		return -EBUSY;
 
+	priv = xzalloc(sizeof(*priv));
+
+	priv->base	= base;
+	cdev		= &priv->cdev;
+	cdev->dev	= dev;
+	cdev->ops	= &imx6_ocotp_ops;
+	cdev->priv	= priv;
+	cdev->size	= 32;
+	cdev->name	= asprintf("imx-ocotp");
+	if (cdev->name == NULL)
+		return -ENOMEM;
+
+	ret = devfs_create(cdev);
+
 	imx_ocotp_init_dt(dev, base);
 
 	return 0;
diff --git a/commands/Kconfig b/commands/Kconfig
index 352e8bf..736b4fc 100644
--- a/commands/Kconfig
+++ b/commands/Kconfig
@@ -739,6 +739,17 @@ config CMD_MIITOOL
 	  detailed MII status information, such as MII capabilities,
 	  current advertising mode, and link partner capabilities.
 
+config CMD_OCOTPTOOL
+	bool
+	default n
+	depends on IMX_OCOTP
+	prompt "ocotptool"
+	help
+	  The ocotptool command allows to read and write to i.MX6 On-Chip
+	  OTP registers from barebox shell. Usage:
+		"ocotptool read mac" to read MAC
+		"ocotptool blow mac xx:xx:xx:xx:xx:xx" to write MAC
+
 config CMD_CLK
 	tristate
 	depends on COMMON_CLK
diff --git a/commands/Makefile b/commands/Makefile
index 91ec0e9..dfdc735 100644
--- a/commands/Makefile
+++ b/commands/Makefile
@@ -94,3 +94,4 @@ obj-$(CONFIG_CMD_DETECT)	+= detect.o
 obj-$(CONFIG_CMD_BOOT)		+= boot.o
 obj-$(CONFIG_CMD_DEVINFO)	+= devinfo.o
 obj-$(CONFIG_CMD_READF)		+= readf.o
+obj-$(CONFIG_CMD_OCOTPTOOL)	+= ocotptool.o
diff --git a/commands/ocotptool.c b/commands/ocotptool.c
new file mode 100644
index 0000000..7259d19
--- /dev/null
+++ b/commands/ocotptool.c
@@ -0,0 +1,150 @@
+/*
+ * ocotptool.c
+ *
+ * Copyright (c) 2014 Phytec Messtechnik GmbH
+ *
+ * Uladzimir Bely <u.bely at sam-solutions.com>,
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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.
+ *
+ */
+
+#include <common.h>
+#include <command.h>
+#include <complete.h>
+#include <driver.h>
+#include <getopt.h>
+#include <fcntl.h>
+
+#define DEVICENAME	"imx-ocotp"
+
+#define MAC_LEN		6
+#define BYTE_LEN	2
+#define MAC_STRLEN	(MAC_LEN * BYTE_LEN + MAC_LEN - 1)
+
+static int parse_mac(char *mac_str, char *mac_bin)
+{
+	int i;
+
+	if (strlen(mac_str) != MAC_STRLEN)
+		return 1;
+
+	for (i = 0; i < MAC_LEN; i++) {
+		char *start, *end;
+
+		start = mac_str + i * (BYTE_LEN + 1);
+		mac_bin[i] = simple_strtoul(start, &end, 16);
+		if (end - start != BYTE_LEN
+			|| (*end != ':' && *end)
+			|| *start == '-')
+			return 1;
+	}
+
+	return 0;
+}
+
+static int read_mac(void)
+{
+	struct cdev *cdev;
+	char *name = asprintf(DEVICENAME);
+	int ret = 0;
+	char buf[128];
+
+	cdev = cdev_open(name, O_RDONLY);
+	if (!cdev)
+		return -ENODEV;
+	ret = cdev_read(cdev, buf, 2*4, 0x22 * 4, 0);
+	if (ret) {
+		printf("MAC is %02x:%02x:%02x:%02x:%02x:%02x\n",
+			buf[5], buf[4], buf[3], buf[2], buf[1], buf[0]);
+	}
+	cdev_close(cdev);
+	free(name);
+
+	return ret;
+}
+
+static int write_mac(char *str)
+{
+	struct cdev *cdev;
+	char *name = asprintf(DEVICENAME);
+	int ret = 0;
+	char buf[128];
+
+	buf[0] = str[5]; buf[1] = str[4];
+	buf[2] = str[3]; buf[3] = str[2];
+	buf[4] = str[1]; buf[5] = str[0];
+	buf[6] = 0; buf[7] = 0;
+	cdev = cdev_open(name, O_RDONLY);
+	if (!cdev)
+		return -ENODEV;
+	printf("Writing MAC to OCOTP registers...\n");
+	ret = cdev_write(cdev, buf, 2*4, 0x22 * 4, 0);
+
+	cdev_close(cdev);
+	free(name);
+
+	return ret;
+}
+
+static int do_ocotptool(int argc, char *argv[])
+{
+	int opt, ret = COMMAND_ERROR_USAGE;
+#ifdef CONFIG_IMX_OCOTP_WRITE
+	char	str[12];
+#endif
+
+	while ((opt = getopt(argc, argv, "r:w:")) > 0) {
+		switch (opt) {
+		case 'r':
+			if (!strcmp(optarg, "mac"))
+				ret = read_mac();
+			else
+				return COMMAND_ERROR_USAGE;
+			break;
+		case 'w':
+#ifdef CONFIG_IMX_OCOTP_WRITE
+			if (!strcmp(optarg, "mac")) {
+				if (optind >= argc) {
+					printf("%s: specify MAC\n", argv[0]);
+					return COMMAND_ERROR_USAGE;
+				}
+				if (parse_mac(argv[optind], str)) {
+					printf("%s: incorrect MAC\n", argv[0]);
+					return COMMAND_ERROR_USAGE;
+				}
+				ret = write_mac(str);
+			} else
+				return COMMAND_ERROR_USAGE;
+#else
+			printf("OCOTP write support is disabled in barebox\n");
+			return 0;
+#endif
+			break;
+		default:
+			break;
+		}
+	}
+	return ret;
+}
+
+BAREBOX_CMD_HELP_START(ocotptool)
+BAREBOX_CMD_HELP_USAGE("ocotptool [OPTIONS]\n")
+BAREBOX_CMD_HELP_SHORT("Example:\n")
+BAREBOX_CMD_HELP_SHORT("  Reading MAC: ocotptool -r mac\n")
+BAREBOX_CMD_HELP_SHORT("  Writing MAC: ocotptool -w mac xx:xx:xx:xx:xx:xx\n")
+BAREBOX_CMD_HELP_END
+
+BAREBOX_CMD_START(ocotptool)
+	.cmd		= do_ocotptool,
+	.usage		= "read/write i.MX6 fuses (MAC)",
+	BAREBOX_CMD_COMPLETE(device_complete)
+	BAREBOX_CMD_HELP(cmd_ocotptool_help)
+BAREBOX_CMD_END
-- 
1.8.3.2




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