1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * i.MX9 OCOTP fusebox driver
  4 *
  5 * Copyright 2023 NXP
  6 */
  7
  8#include <linux/device.h>
  9#include <linux/io.h>
 10#include <linux/module.h>
 11#include <linux/nvmem-provider.h>
 12#include <linux/of.h>
 13#include <linux/platform_device.h>
 14#include <linux/slab.h>
 15
 16enum fuse_type {
 17	FUSE_FSB = 1,
 18	FUSE_ELE = 2,
 19	FUSE_INVALID = -1
 20};
 21
 22struct ocotp_map_entry {
 23	u32 start; /* start word */
 24	u32 num; /* num words */
 25	enum fuse_type type;
 26};
 27
 28struct ocotp_devtype_data {
 29	u32 reg_off;
 30	char *name;
 31	u32 size;
 32	u32 num_entry;
 33	u32 flag;
 34	nvmem_reg_read_t reg_read;
 35	struct ocotp_map_entry entry[];
 36};
 37
 38struct imx_ocotp_priv {
 39	struct device *dev;
 40	void __iomem *base;
 41	struct nvmem_config config;
 42	struct mutex lock;
 43	const struct ocotp_devtype_data *data;
 44};
 45
 46static enum fuse_type imx_ocotp_fuse_type(void *context, u32 index)
 47{
 48	struct imx_ocotp_priv *priv = context;
 49	const struct ocotp_devtype_data *data = priv->data;
 50	u32 start, end;
 51	int i;
 52
 53	for (i = 0; i < data->num_entry; i++) {
 54		start = data->entry[i].start;
 55		end = data->entry[i].start + data->entry[i].num;
 56
 57		if (index >= start && index < end)
 58			return data->entry[i].type;
 59	}
 60
 61	return FUSE_INVALID;
 62}
 63
 64static int imx_ocotp_reg_read(void *context, unsigned int offset, void *val, size_t bytes)
 65{
 66	struct imx_ocotp_priv *priv = context;
 67	void __iomem *reg = priv->base + priv->data->reg_off;
 68	u32 count, index, num_bytes;
 69	enum fuse_type type;
 70	u32 *buf;
 71	void *p;
 72	int i;
 73
 74	index = offset;
 75	num_bytes = round_up(bytes, 4);
 76	count = num_bytes >> 2;
 77
 78	if (count > ((priv->data->size >> 2) - index))
 79		count = (priv->data->size >> 2) - index;
 80
 81	p = kzalloc(num_bytes, GFP_KERNEL);
 82	if (!p)
 83		return -ENOMEM;
 84
 85	mutex_lock(&priv->lock);
 86
 87	buf = p;
 88
 89	for (i = index; i < (index + count); i++) {
 90		type = imx_ocotp_fuse_type(context, i);
 91		if (type == FUSE_INVALID || type == FUSE_ELE) {
 92			*buf++ = 0;
 93			continue;
 94		}
 95
 96		*buf++ = readl_relaxed(reg + (i << 2));
 97	}
 98
 99	memcpy(val, (u8 *)p, bytes);
100
101	mutex_unlock(&priv->lock);
102
103	kfree(p);
104
105	return 0;
106};
107
108static int imx_ele_ocotp_probe(struct platform_device *pdev)
109{
110	struct device *dev = &pdev->dev;
111	struct imx_ocotp_priv *priv;
112	struct nvmem_device *nvmem;
113
114	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
115	if (!priv)
116		return -ENOMEM;
117
118	priv->data = of_device_get_match_data(dev);
119
120	priv->base = devm_platform_ioremap_resource(pdev, 0);
121	if (IS_ERR(priv->base))
122		return PTR_ERR(priv->base);
123
124	priv->config.dev = dev;
125	priv->config.name = "ELE-OCOTP";
126	priv->config.id = NVMEM_DEVID_AUTO;
127	priv->config.owner = THIS_MODULE;
128	priv->config.size = priv->data->size;
129	priv->config.reg_read = priv->data->reg_read;
130	priv->config.word_size = 4;
131	priv->config.stride = 1;
132	priv->config.priv = priv;
133	priv->config.read_only = true;
134	mutex_init(&priv->lock);
135
136	nvmem = devm_nvmem_register(dev, &priv->config);
137	if (IS_ERR(nvmem))
138		return PTR_ERR(nvmem);
139
140	return 0;
141}
142
143static const struct ocotp_devtype_data imx93_ocotp_data = {
144	.reg_off = 0x8000,
145	.reg_read = imx_ocotp_reg_read,
146	.size = 2048,
147	.num_entry = 6,
148	.entry = {
149		{ 0, 52, FUSE_FSB },
150		{ 63, 1, FUSE_ELE},
151		{ 128, 16, FUSE_ELE },
152		{ 182, 1, FUSE_ELE },
153		{ 188, 1, FUSE_ELE },
154		{ 312, 200, FUSE_FSB }
155	},
156};
157
158static const struct of_device_id imx_ele_ocotp_dt_ids[] = {
159	{ .compatible = "fsl,imx93-ocotp", .data = &imx93_ocotp_data, },
160	{},
161};
162MODULE_DEVICE_TABLE(of, imx_ele_ocotp_dt_ids);
163
164static struct platform_driver imx_ele_ocotp_driver = {
165	.driver = {
166		.name = "imx_ele_ocotp",
167		.of_match_table = imx_ele_ocotp_dt_ids,
168	},
169	.probe = imx_ele_ocotp_probe,
170};
171module_platform_driver(imx_ele_ocotp_driver);
172
173MODULE_DESCRIPTION("i.MX OCOTP/ELE driver");
174MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
175MODULE_LICENSE("GPL");