drivers/nvmem/bcm-ocotp.c - linux - Git at Google

 /*
  * Copyright (C) 2016 Broadcom
  *
  * 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 version 2.
  *
  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  * kind, whether express or implied; without even the implied warranty
  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <linux/acpi.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/io.h>
 #include <linux/module.h>
 #include <linux/nvmem-provider.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/platform_device.h>

 /*
  * # of tries for OTP Status. The time to execute a command varies. The slowest
  * commands are writes which also vary based on the # of bits turned on. Writing
  * 0xffffffff takes ~3800 us.
  */
 #define OTPC_RETRIES                 5000

 /* Sequence to enable OTP program */
 #define OTPC_PROG_EN_SEQ             { 0xf, 0x4, 0x8, 0xd }

 /* OTPC Commands */
 #define OTPC_CMD_READ                0x0
 #define OTPC_CMD_OTP_PROG_ENABLE     0x2
 #define OTPC_CMD_OTP_PROG_DISABLE    0x3
 #define OTPC_CMD_PROGRAM             0x8

 /* OTPC Status Bits */
 #define OTPC_STAT_CMD_DONE           BIT(1)
 #define OTPC_STAT_PROG_OK            BIT(2)

 /* OTPC register definition */
 #define OTPC_MODE_REG_OFFSET         0x0
 #define OTPC_MODE_REG_OTPC_MODE      0
 #define OTPC_COMMAND_OFFSET          0x4
 #define OTPC_COMMAND_COMMAND_WIDTH   6
 #define OTPC_CMD_START_OFFSET        0x8
 #define OTPC_CMD_START_START         0
 #define OTPC_CPU_STATUS_OFFSET       0xc
 #define OTPC_CPUADDR_REG_OFFSET      0x28
 #define OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH 16
 #define OTPC_CPU_WRITE_REG_OFFSET    0x2c

 #define OTPC_CMD_MASK  (BIT(OTPC_COMMAND_COMMAND_WIDTH) - 1)
 #define OTPC_ADDR_MASK (BIT(OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH) - 1)


 struct otpc_map {
 	/* in words. */
 	u32 otpc_row_size;
 	/* 128 bit row / 4 words support. */
 	u16 data_r_offset[4];
 	/* 128 bit row / 4 words support. */
 	u16 data_w_offset[4];
 };

 static struct otpc_map otp_map = {
 	.otpc_row_size = 1,
 	.data_r_offset = {0x10},
 	.data_w_offset = {0x2c},
 };

 static struct otpc_map otp_map_v2 = {
 	.otpc_row_size = 2,
 	.data_r_offset = {0x10, 0x5c},
 	.data_w_offset = {0x2c, 0x64},
 };

 struct otpc_priv {
 	struct device *dev;
 	void __iomem *base;
 	const struct otpc_map *map;
 	struct nvmem_config *config;
 };

 static inline void set_command(void __iomem *base, u32 command)
 {
 	writel(command & OTPC_CMD_MASK, base + OTPC_COMMAND_OFFSET);
 }

 static inline void set_cpu_address(void __iomem *base, u32 addr)
 {
 	writel(addr & OTPC_ADDR_MASK, base + OTPC_CPUADDR_REG_OFFSET);
 }

 static inline void set_start_bit(void __iomem *base)
 {
 	writel(1 << OTPC_CMD_START_START, base + OTPC_CMD_START_OFFSET);
 }

 static inline void reset_start_bit(void __iomem *base)
 {
 	writel(0, base + OTPC_CMD_START_OFFSET);
 }

 static inline void write_cpu_data(void __iomem *base, u32 value)
 {
 	writel(value, base + OTPC_CPU_WRITE_REG_OFFSET);
 }

 static int poll_cpu_status(void __iomem *base, u32 value)
 {
 	u32 status;
 	u32 retries;

 	for (retries = 0; retries < OTPC_RETRIES; retries++) {
 		status = readl(base + OTPC_CPU_STATUS_OFFSET);
 		if (status & value)
 			break;
 		udelay(1);
 	}
 	if (retries == OTPC_RETRIES)
 		return -EAGAIN;

 	return 0;
 }

 static int enable_ocotp_program(void __iomem *base)
 {
 	static const u32 vals[] = OTPC_PROG_EN_SEQ;
 	int i;
 	int ret;

 	/* Write the magic sequence to enable programming */
 	set_command(base, OTPC_CMD_OTP_PROG_ENABLE);
 	for (i = 0; i < ARRAY_SIZE(vals); i++) {
 		write_cpu_data(base, vals[i]);
 		set_start_bit(base);
 		ret = poll_cpu_status(base, OTPC_STAT_CMD_DONE);
 		reset_start_bit(base);
 		if (ret)
 			return ret;
 	}

 	return poll_cpu_status(base, OTPC_STAT_PROG_OK);
 }

 static int disable_ocotp_program(void __iomem *base)
 {
 	int ret;

 	set_command(base, OTPC_CMD_OTP_PROG_DISABLE);
 	set_start_bit(base);
 	ret = poll_cpu_status(base, OTPC_STAT_PROG_OK);
 	reset_start_bit(base);

 	return ret;
 }

 static int bcm_otpc_read(void *context, unsigned int offset, void *val,
 	size_t bytes)
 {
 	struct otpc_priv *priv = context;
 	u32 *buf = val;
 	u32 bytes_read;
 	u32 address = offset / priv->config->word_size;
 	int i, ret;

 	for (bytes_read = 0; bytes_read < bytes;) {
 		set_command(priv->base, OTPC_CMD_READ);
 		set_cpu_address(priv->base, address++);
 		set_start_bit(priv->base);
 		ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
 		if (ret) {
 			dev_err(priv->dev, "otp read error: 0x%x", ret);
 			return -EIO;
 		}

 		for (i = 0; i < priv->map->otpc_row_size; i++) {
 			*buf++ = readl(priv->base +
 					priv->map->data_r_offset[i]);
 			bytes_read += sizeof(*buf);
 		}

 		reset_start_bit(priv->base);
 	}

 	return 0;
 }

 static int bcm_otpc_write(void *context, unsigned int offset, void *val,
 	size_t bytes)
 {
 	struct otpc_priv *priv = context;
 	u32 *buf = val;
 	u32 bytes_written;
 	u32 address = offset / priv->config->word_size;
 	int i, ret;

 	if (offset % priv->config->word_size)
 		return -EINVAL;

 	ret = enable_ocotp_program(priv->base);
 	if (ret)
 		return -EIO;

 	for (bytes_written = 0; bytes_written < bytes;) {
 		set_command(priv->base, OTPC_CMD_PROGRAM);
 		set_cpu_address(priv->base, address++);
 		for (i = 0; i < priv->map->otpc_row_size; i++) {
 			writel(*buf, priv->base + priv->map->data_w_offset[i]);
 			buf++;
 			bytes_written += sizeof(*buf);
 		}
 		set_start_bit(priv->base);
 		ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
 		reset_start_bit(priv->base);
 		if (ret) {
 			dev_err(priv->dev, "otp write error: 0x%x", ret);
 			return -EIO;
 		}
 	}

 	disable_ocotp_program(priv->base);

 	return 0;
 }

 static struct nvmem_config bcm_otpc_nvmem_config = {
 	.name = "bcm-ocotp",
 	.read_only = false,
 	.word_size = 4,
 	.stride = 4,
 	.reg_read = bcm_otpc_read,
 	.reg_write = bcm_otpc_write,
 };

 static const struct of_device_id bcm_otpc_dt_ids[] = {
 	{ .compatible = "brcm,ocotp", .data = &otp_map },
 	{ .compatible = "brcm,ocotp-v2", .data = &otp_map_v2 },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids);

 static const struct acpi_device_id bcm_otpc_acpi_ids[] __maybe_unused = {
 	{ .id = "BRCM0700", .driver_data = (kernel_ulong_t)&otp_map },
 	{ .id = "BRCM0701", .driver_data = (kernel_ulong_t)&otp_map_v2 },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(acpi, bcm_otpc_acpi_ids);

 static int bcm_otpc_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct resource *res;
 	struct otpc_priv *priv;
 	struct nvmem_device *nvmem;
 	int err;
 	u32 num_words;

 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
 	if (!priv)
 		return -ENOMEM;

 	priv->map = device_get_match_data(dev);
 	if (!priv->map)
 		return -ENODEV;

 	/* Get OTP base address register. */
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	priv->base = devm_ioremap_resource(dev, res);
 	if (IS_ERR(priv->base)) {
 		dev_err(dev, "unable to map I/O memory\n");
 		return PTR_ERR(priv->base);
 	}

 	/* Enable CPU access to OTPC. */
 	writel(readl(priv->base + OTPC_MODE_REG_OFFSET) |
 		BIT(OTPC_MODE_REG_OTPC_MODE),
 		priv->base + OTPC_MODE_REG_OFFSET);
 	reset_start_bit(priv->base);

 	/* Read size of memory in words. */
 	err = device_property_read_u32(dev, "brcm,ocotp-size", &num_words);
 	if (err) {
 		dev_err(dev, "size parameter not specified\n");
 		return -EINVAL;
 	} else if (num_words == 0) {
 		dev_err(dev, "size must be > 0\n");
 		return -EINVAL;
 	}

 	bcm_otpc_nvmem_config.size = 4 * num_words;
 	bcm_otpc_nvmem_config.dev = dev;
 	bcm_otpc_nvmem_config.priv = priv;

 	if (priv->map == &otp_map_v2) {
 		bcm_otpc_nvmem_config.word_size = 8;
 		bcm_otpc_nvmem_config.stride = 8;
 	}

 	priv->config = &bcm_otpc_nvmem_config;

 	nvmem = devm_nvmem_register(dev, &bcm_otpc_nvmem_config);
 	if (IS_ERR(nvmem)) {
 		dev_err(dev, "error registering nvmem config\n");
 		return PTR_ERR(nvmem);
 	}

 	return 0;
 }

 static struct platform_driver bcm_otpc_driver = {
 	.probe	= bcm_otpc_probe,
 	.driver = {
 		.name	= "brcm-otpc",
 		.of_match_table = bcm_otpc_dt_ids,
 		.acpi_match_table = ACPI_PTR(bcm_otpc_acpi_ids),
 	},
 };
 module_platform_driver(bcm_otpc_driver);

 MODULE_DESCRIPTION("Broadcom OTPC driver");
 MODULE_LICENSE("GPL v2");
	/*
	* Copyright (C) 2016 Broadcom
	*
	* 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 version 2.
	*
	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	* kind, whether express or implied; without even the implied warranty
	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <linux/acpi.h>
	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/io.h>
	#include <linux/module.h>
	#include <linux/nvmem-provider.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/platform_device.h>

	/*
	* # of tries for OTP Status. The time to execute a command varies. The slowest
	* commands are writes which also vary based on the # of bits turned on. Writing
	* 0xffffffff takes ~3800 us.
	*/
	#define OTPC_RETRIES 5000

	/* Sequence to enable OTP program */
	#define OTPC_PROG_EN_SEQ { 0xf, 0x4, 0x8, 0xd }

	/* OTPC Commands */
	#define OTPC_CMD_READ 0x0
	#define OTPC_CMD_OTP_PROG_ENABLE 0x2
	#define OTPC_CMD_OTP_PROG_DISABLE 0x3
	#define OTPC_CMD_PROGRAM 0x8

	/* OTPC Status Bits */
	#define OTPC_STAT_CMD_DONE BIT(1)
	#define OTPC_STAT_PROG_OK BIT(2)

	/* OTPC register definition */
	#define OTPC_MODE_REG_OFFSET 0x0
	#define OTPC_MODE_REG_OTPC_MODE 0
	#define OTPC_COMMAND_OFFSET 0x4
	#define OTPC_COMMAND_COMMAND_WIDTH 6
	#define OTPC_CMD_START_OFFSET 0x8
	#define OTPC_CMD_START_START 0
	#define OTPC_CPU_STATUS_OFFSET 0xc
	#define OTPC_CPUADDR_REG_OFFSET 0x28
	#define OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH 16
	#define OTPC_CPU_WRITE_REG_OFFSET 0x2c

	#define OTPC_CMD_MASK (BIT(OTPC_COMMAND_COMMAND_WIDTH) - 1)
	#define OTPC_ADDR_MASK (BIT(OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH) - 1)


	struct otpc_map {
	/* in words. */
	u32 otpc_row_size;
	/* 128 bit row / 4 words support. */
	u16 data_r_offset[4];
	/* 128 bit row / 4 words support. */
	u16 data_w_offset[4];
	};

	static struct otpc_map otp_map = {
	.otpc_row_size = 1,
	.data_r_offset = {0x10},
	.data_w_offset = {0x2c},
	};

	static struct otpc_map otp_map_v2 = {
	.otpc_row_size = 2,
	.data_r_offset = {0x10, 0x5c},
	.data_w_offset = {0x2c, 0x64},
	};

	struct otpc_priv {
	struct device *dev;
	void __iomem *base;
	const struct otpc_map *map;
	struct nvmem_config *config;
	};

	static inline void set_command(void __iomem *base, u32 command)
	{
	writel(command & OTPC_CMD_MASK, base + OTPC_COMMAND_OFFSET);
	}

	static inline void set_cpu_address(void __iomem *base, u32 addr)
	{
	writel(addr & OTPC_ADDR_MASK, base + OTPC_CPUADDR_REG_OFFSET);
	}

	static inline void set_start_bit(void __iomem *base)
	{
	writel(1 << OTPC_CMD_START_START, base + OTPC_CMD_START_OFFSET);
	}

	static inline void reset_start_bit(void __iomem *base)
	{
	writel(0, base + OTPC_CMD_START_OFFSET);
	}

	static inline void write_cpu_data(void __iomem *base, u32 value)
	{
	writel(value, base + OTPC_CPU_WRITE_REG_OFFSET);
	}

	static int poll_cpu_status(void __iomem *base, u32 value)
	{
	u32 status;
	u32 retries;

	for (retries = 0; retries < OTPC_RETRIES; retries++) {
	status = readl(base + OTPC_CPU_STATUS_OFFSET);
	if (status & value)
	break;
	udelay(1);
	}
	if (retries == OTPC_RETRIES)
	return -EAGAIN;

	return 0;
	}

	static int enable_ocotp_program(void __iomem *base)
	{
	static const u32 vals[] = OTPC_PROG_EN_SEQ;
	int i;
	int ret;

	/* Write the magic sequence to enable programming */
	set_command(base, OTPC_CMD_OTP_PROG_ENABLE);
	for (i = 0; i < ARRAY_SIZE(vals); i++) {
	write_cpu_data(base, vals[i]);
	set_start_bit(base);
	ret = poll_cpu_status(base, OTPC_STAT_CMD_DONE);
	reset_start_bit(base);
	if (ret)
	return ret;
	}

	return poll_cpu_status(base, OTPC_STAT_PROG_OK);
	}

	static int disable_ocotp_program(void __iomem *base)
	{
	int ret;

	set_command(base, OTPC_CMD_OTP_PROG_DISABLE);
	set_start_bit(base);
	ret = poll_cpu_status(base, OTPC_STAT_PROG_OK);
	reset_start_bit(base);

	return ret;
	}

	static int bcm_otpc_read(void context, unsigned int offset, void val,
	size_t bytes)
	{
	struct otpc_priv *priv = context;
	u32 *buf = val;
	u32 bytes_read;
	u32 address = offset / priv->config->word_size;
	int i, ret;

	for (bytes_read = 0; bytes_read < bytes;) {
	set_command(priv->base, OTPC_CMD_READ);
	set_cpu_address(priv->base, address++);
	set_start_bit(priv->base);
	ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
	if (ret) {
	dev_err(priv->dev, "otp read error: 0x%x", ret);
	return -EIO;
	}

	for (i = 0; i < priv->map->otpc_row_size; i++) {
	*buf++ = readl(priv->base +
	priv->map->data_r_offset[i]);
	bytes_read += sizeof(*buf);
	}

	reset_start_bit(priv->base);
	}

	return 0;
	}

	static int bcm_otpc_write(void context, unsigned int offset, void val,
	size_t bytes)
	{
	struct otpc_priv *priv = context;
	u32 *buf = val;
	u32 bytes_written;
	u32 address = offset / priv->config->word_size;
	int i, ret;

	if (offset % priv->config->word_size)
	return -EINVAL;

	ret = enable_ocotp_program(priv->base);
	if (ret)
	return -EIO;

	for (bytes_written = 0; bytes_written < bytes;) {
	set_command(priv->base, OTPC_CMD_PROGRAM);
	set_cpu_address(priv->base, address++);
	for (i = 0; i < priv->map->otpc_row_size; i++) {
	writel(*buf, priv->base + priv->map->data_w_offset[i]);
	buf++;
	bytes_written += sizeof(*buf);
	}
	set_start_bit(priv->base);
	ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
	reset_start_bit(priv->base);
	if (ret) {
	dev_err(priv->dev, "otp write error: 0x%x", ret);
	return -EIO;
	}
	}

	disable_ocotp_program(priv->base);

	return 0;
	}

	static struct nvmem_config bcm_otpc_nvmem_config = {
	.name = "bcm-ocotp",
	.read_only = false,
	.word_size = 4,
	.stride = 4,
	.reg_read = bcm_otpc_read,
	.reg_write = bcm_otpc_write,
	};

	static const struct of_device_id bcm_otpc_dt_ids[] = {
	{ .compatible = "brcm,ocotp", .data = &otp_map },
	{ .compatible = "brcm,ocotp-v2", .data = &otp_map_v2 },
	{ },
	};
	MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids);

	static const struct acpi_device_id bcm_otpc_acpi_ids[] __maybe_unused = {
	{ .id = "BRCM0700", .driver_data = (kernel_ulong_t)&otp_map },
	{ .id = "BRCM0701", .driver_data = (kernel_ulong_t)&otp_map_v2 },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(acpi, bcm_otpc_acpi_ids);

	static int bcm_otpc_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct resource *res;
	struct otpc_priv *priv;
	struct nvmem_device *nvmem;
	int err;
	u32 num_words;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
	return -ENOMEM;

	priv->map = device_get_match_data(dev);
	if (!priv->map)
	return -ENODEV;

	/* Get OTP base address register. */
	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	priv->base = devm_ioremap_resource(dev, res);
	if (IS_ERR(priv->base)) {
	dev_err(dev, "unable to map I/O memory\n");
	return PTR_ERR(priv->base);
	}

	/* Enable CPU access to OTPC. */
	writel(readl(priv->base + OTPC_MODE_REG_OFFSET) \|
	BIT(OTPC_MODE_REG_OTPC_MODE),
	priv->base + OTPC_MODE_REG_OFFSET);
	reset_start_bit(priv->base);

	/* Read size of memory in words. */
	err = device_property_read_u32(dev, "brcm,ocotp-size", &num_words);
	if (err) {
	dev_err(dev, "size parameter not specified\n");
	return -EINVAL;
	} else if (num_words == 0) {
	dev_err(dev, "size must be > 0\n");
	return -EINVAL;
	}

	bcm_otpc_nvmem_config.size = 4 * num_words;
	bcm_otpc_nvmem_config.dev = dev;
	bcm_otpc_nvmem_config.priv = priv;

	if (priv->map == &otp_map_v2) {
	bcm_otpc_nvmem_config.word_size = 8;
	bcm_otpc_nvmem_config.stride = 8;
	}

	priv->config = &bcm_otpc_nvmem_config;

	nvmem = devm_nvmem_register(dev, &bcm_otpc_nvmem_config);
	if (IS_ERR(nvmem)) {
	dev_err(dev, "error registering nvmem config\n");
	return PTR_ERR(nvmem);
	}

	return 0;
	}

	static struct platform_driver bcm_otpc_driver = {
	.probe = bcm_otpc_probe,
	.driver = {
	.name = "brcm-otpc",
	.of_match_table = bcm_otpc_dt_ids,
	.acpi_match_table = ACPI_PTR(bcm_otpc_acpi_ids),
	},
	};
	module_platform_driver(bcm_otpc_driver);

	MODULE_DESCRIPTION("Broadcom OTPC driver");
	MODULE_LICENSE("GPL v2");