[linux.git] / drivers / nvmem / bcm-ocotp.c

/*
 * 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/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_address.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             0xA

/* 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;
	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_r_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,
	.owner = THIS_MODULE,
	.reg_read = bcm_otpc_read,
	.reg_write = bcm_otpc_write,
};

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

static int bcm_otpc_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *dn = dev->of_node;
	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;

	if (of_device_is_compatible(dev->of_node, "brcm,ocotp"))
		priv->map = &otp_map;
	else if (of_device_is_compatible(dev->of_node, "brcm,ocotp-v2"))
		priv->map = &otp_map_v2;
	else {
		dev_err(&pdev->dev,
			"%s otpc config map not defined\n", __func__);
		return -EINVAL;
	}

	/* 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 = of_property_read_u32(dn, "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 (of_device_is_compatible(dev->of_node, "brcm,ocotp-v2")) {
		bcm_otpc_nvmem_config.word_size = 8;
		bcm_otpc_nvmem_config.stride = 8;
	}

	priv->config = &bcm_otpc_nvmem_config;

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

	platform_set_drvdata(pdev, nvmem);

	return 0;
}

static int bcm_otpc_remove(struct platform_device *pdev)
{
	struct nvmem_device *nvmem = platform_get_drvdata(pdev);

	return nvmem_unregister(nvmem);
}

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

MODULE_DESCRIPTION("Broadcom OTPC driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
9d59c6e8 JR	1	/*
	2	* Copyright (C) 2016 Broadcom
	3	*
	4	* This program is free software; you can redistribute it and/or
	5	* modify it under the terms of the GNU General Public License as
	6	* published by the Free Software Foundation version 2.
	7	*
	8	* This program is distributed "as is" WITHOUT ANY WARRANTY of any
	9	* kind, whether express or implied; without even the implied warranty
	10	* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	11	* GNU General Public License for more details.
	12	*/
	13
	14	#include <linux/delay.h>
	15	#include <linux/device.h>
	16	#include <linux/io.h>
	17	#include <linux/module.h>
	18	#include <linux/nvmem-provider.h>
	19	#include <linux/of.h>
	20	#include <linux/of_address.h>
	21	#include <linux/platform_device.h>
	22
	23	/*
	24	* # of tries for OTP Status. The time to execute a command varies. The slowest
	25	* commands are writes which also vary based on the # of bits turned on. Writing
	26	* 0xffffffff takes ~3800 us.
	27	*/
	28	#define OTPC_RETRIES 5000
	29
	30	/* Sequence to enable OTP program */
	31	#define OTPC_PROG_EN_SEQ { 0xf, 0x4, 0x8, 0xd }
	32
	33	/* OTPC Commands */
	34	#define OTPC_CMD_READ 0x0
	35	#define OTPC_CMD_OTP_PROG_ENABLE 0x2
	36	#define OTPC_CMD_OTP_PROG_DISABLE 0x3
	37	#define OTPC_CMD_PROGRAM 0xA
	38
	39	/* OTPC Status Bits */
	40	#define OTPC_STAT_CMD_DONE BIT(1)
	41	#define OTPC_STAT_PROG_OK BIT(2)
	42
	43	/* OTPC register definition */
	44	#define OTPC_MODE_REG_OFFSET 0x0
	45	#define OTPC_MODE_REG_OTPC_MODE 0
	46	#define OTPC_COMMAND_OFFSET 0x4
	47	#define OTPC_COMMAND_COMMAND_WIDTH 6
	48	#define OTPC_CMD_START_OFFSET 0x8
	49	#define OTPC_CMD_START_START 0
	50	#define OTPC_CPU_STATUS_OFFSET 0xc
	51	#define OTPC_CPUADDR_REG_OFFSET 0x28
	52	#define OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH 16
	53	#define OTPC_CPU_WRITE_REG_OFFSET 0x2c
	54
	55	#define OTPC_CMD_MASK (BIT(OTPC_COMMAND_COMMAND_WIDTH) - 1)
	56	#define OTPC_ADDR_MASK (BIT(OTPC_CPUADDR_REG_OTPC_CPU_ADDRESS_WIDTH) - 1)
	57
	58
	59	struct otpc_map {
	60	/* in words. */
	61	u32 otpc_row_size;
	62	/* 128 bit row / 4 words support. */
	63	u16 data_r_offset[4];
	64	/* 128 bit row / 4 words support. */
65	u16 data_w_offset[4];
66	};
67
68	static struct otpc_map otp_map = {
69	.otpc_row_size = 1,
70	.data_r_offset = {0x10},
71	.data_w_offset = {0x2c},
72	};
73
74	static struct otpc_map otp_map_v2 = {
75	.otpc_row_size = 2,
76	.data_r_offset = {0x10, 0x5c},
77	.data_w_offset = {0x2c, 0x64},
78	};
79
80	struct otpc_priv {
81	struct device *dev;
82	void __iomem *base;
83	struct otpc_map *map;
84	struct nvmem_config *config;
85	};
86
87	static inline void set_command(void __iomem *base, u32 command)
88	{
89	writel(command & OTPC_CMD_MASK, base + OTPC_COMMAND_OFFSET);
90	}
91
92	static inline void set_cpu_address(void __iomem *base, u32 addr)
93	{
94	writel(addr & OTPC_ADDR_MASK, base + OTPC_CPUADDR_REG_OFFSET);
95	}
96
97	static inline void set_start_bit(void __iomem *base)
98	{
99	writel(1 << OTPC_CMD_START_START, base + OTPC_CMD_START_OFFSET);
100	}
101
102	static inline void reset_start_bit(void __iomem *base)
103	{
104	writel(0, base + OTPC_CMD_START_OFFSET);
105	}
106
107	static inline void write_cpu_data(void __iomem *base, u32 value)
108	{
109	writel(value, base + OTPC_CPU_WRITE_REG_OFFSET);
110	}
111
112	static int poll_cpu_status(void __iomem *base, u32 value)
113	{
114	u32 status;
115	u32 retries;
116
117	for (retries = 0; retries < OTPC_RETRIES; retries++) {
118	status = readl(base + OTPC_CPU_STATUS_OFFSET);
119	if (status & value)
120	break;
121	udelay(1);
122	}
123	if (retries == OTPC_RETRIES)
124	return -EAGAIN;
125
126	return 0;
127	}
128
129	static int enable_ocotp_program(void __iomem *base)
130	{
131	static const u32 vals[] = OTPC_PROG_EN_SEQ;
132	int i;
133	int ret;
134
135	/* Write the magic sequence to enable programming */
136	set_command(base, OTPC_CMD_OTP_PROG_ENABLE);
137	for (i = 0; i < ARRAY_SIZE(vals); i++) {
138	write_cpu_data(base, vals[i]);
139	set_start_bit(base);
140	ret = poll_cpu_status(base, OTPC_STAT_CMD_DONE);
141	reset_start_bit(base);
142	if (ret)
143	return ret;
144	}
145
146	return poll_cpu_status(base, OTPC_STAT_PROG_OK);
147	}
148
149	static int disable_ocotp_program(void __iomem *base)
150	{
151	int ret;
152
153	set_command(base, OTPC_CMD_OTP_PROG_DISABLE);
154	set_start_bit(base);
155	ret = poll_cpu_status(base, OTPC_STAT_PROG_OK);
156	reset_start_bit(base);
157
158	return ret;
159	}
160
161	static int bcm_otpc_read(void context, unsigned int offset, void val,
162	size_t bytes)
163	{
164	struct otpc_priv *priv = context;
165	u32 *buf = val;
166	u32 bytes_read;
167	u32 address = offset / priv->config->word_size;
168	int i, ret;
169
170	for (bytes_read = 0; bytes_read < bytes;) {
171	set_command(priv->base, OTPC_CMD_READ);
172	set_cpu_address(priv->base, address++);
173	set_start_bit(priv->base);
174	ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
175	if (ret) {
176	dev_err(priv->dev, "otp read error: 0x%x", ret);
177	return -EIO;
178	}
179
180	for (i = 0; i < priv->map->otpc_row_size; i++) {
181	*buf++ = readl(priv->base +
182	priv->map->data_r_offset[i]);
183	bytes_read += sizeof(*buf);
184	}
185
186	reset_start_bit(priv->base);
187	}
188
189	return 0;
190	}
191
192	static int bcm_otpc_write(void context, unsigned int offset, void val,
193	size_t bytes)
194	{
195	struct otpc_priv *priv = context;
196	u32 *buf = val;
197	u32 bytes_written;
198	u32 address = offset / priv->config->word_size;
199	int i, ret;
200
201	if (offset % priv->config->word_size)
202	return -EINVAL;
203
204	ret = enable_ocotp_program(priv->base);
205	if (ret)
206	return -EIO;
207
208	for (bytes_written = 0; bytes_written < bytes;) {
209	set_command(priv->base, OTPC_CMD_PROGRAM);
210	set_cpu_address(priv->base, address++);
211	for (i = 0; i < priv->map->otpc_row_size; i++) {
212	writel(*buf, priv->base + priv->map->data_r_offset[i]);
213	buf++;
214	bytes_written += sizeof(*buf);
215	}
216	set_start_bit(priv->base);
217	ret = poll_cpu_status(priv->base, OTPC_STAT_CMD_DONE);
218	reset_start_bit(priv->base);
219	if (ret) {
220	dev_err(priv->dev, "otp write error: 0x%x", ret);
221	return -EIO;
222	}
223	}
224
225	disable_ocotp_program(priv->base);
226
227	return 0;
228	}
229
230	static struct nvmem_config bcm_otpc_nvmem_config = {
231	.name = "bcm-ocotp",
232	.read_only = false,
233	.word_size = 4,
234	.stride = 4,
235	.owner = THIS_MODULE,
236	.reg_read = bcm_otpc_read,
237	.reg_write = bcm_otpc_write,
238	};
239
240	static const struct of_device_id bcm_otpc_dt_ids[] = {
241	{ .compatible = "brcm,ocotp" },
242	{ .compatible = "brcm,ocotp-v2" },
243	{ },
244	};
245	MODULE_DEVICE_TABLE(of, bcm_otpc_dt_ids);
246
247	static int bcm_otpc_probe(struct platform_device *pdev)
248	{
249	struct device *dev = &pdev->dev;
250	struct device_node *dn = dev->of_node;
251	struct resource *res;
252	struct otpc_priv *priv;
253	struct nvmem_device *nvmem;
254	int err;
255	u32 num_words;
256
257	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
258	if (!priv)
259	return -ENOMEM;
260
261	if (of_device_is_compatible(dev->of_node, "brcm,ocotp"))
262	priv->map = &otp_map;
263	else if (of_device_is_compatible(dev->of_node, "brcm,ocotp-v2"))
264	priv->map = &otp_map_v2;
265	else {
266	dev_err(&pdev->dev,
267	"%s otpc config map not defined\n", __func__);
268	return -EINVAL;
269	}
270
271	/* Get OTP base address register. */
272	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
273	priv->base = devm_ioremap_resource(dev, res);
274	if (IS_ERR(priv->base)) {
275	dev_err(dev, "unable to map I/O memory\n");
276	return PTR_ERR(priv->base);
277	}
278
279	/* Enable CPU access to OTPC. */
280	writel(readl(priv->base + OTPC_MODE_REG_OFFSET) \|
281	BIT(OTPC_MODE_REG_OTPC_MODE),
282	priv->base + OTPC_MODE_REG_OFFSET);
283	reset_start_bit(priv->base);
284
285	/* Read size of memory in words. */
286	err = of_property_read_u32(dn, "brcm,ocotp-size", &num_words);
287	if (err) {
288	dev_err(dev, "size parameter not specified\n");
289	return -EINVAL;
290	} else if (num_words == 0) {
291	dev_err(dev, "size must be > 0\n");
292	return -EINVAL;
293	}
294
295	bcm_otpc_nvmem_config.size = 4 * num_words;
296	bcm_otpc_nvmem_config.dev = dev;
297	bcm_otpc_nvmem_config.priv = priv;
298
299	if (of_device_is_compatible(dev->of_node, "brcm,ocotp-v2")) {
300	bcm_otpc_nvmem_config.word_size = 8;
301	bcm_otpc_nvmem_config.stride = 8;
302	}
303
304	priv->config = &bcm_otpc_nvmem_config;
305
306	nvmem = nvmem_register(&bcm_otpc_nvmem_config);
307	if (IS_ERR(nvmem)) {
308	dev_err(dev, "error registering nvmem config\n");
309	return PTR_ERR(nvmem);
310	}
311
312	platform_set_drvdata(pdev, nvmem);
313
314	return 0;
315	}
316
317	static int bcm_otpc_remove(struct platform_device *pdev)
318	{
319	struct nvmem_device *nvmem = platform_get_drvdata(pdev);
320
321	return nvmem_unregister(nvmem);
322	}
323
324	static struct platform_driver bcm_otpc_driver = {
325	.probe = bcm_otpc_probe,
326	.remove = bcm_otpc_remove,
327	.driver = {
328	.name = "brcm-otpc",
329	.of_match_table = bcm_otpc_dt_ids,
330	},
331	};
332	module_platform_driver(bcm_otpc_driver);
333
334	MODULE_DESCRIPTION("Broadcom OTPC driver");
335	MODULE_LICENSE("GPL v2");