1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Rockchip eFuse Driver
4  *
5  * Copyright (c) 2015 Rockchip Electronics Co. Ltd.
6  * Author: Caesar Wang <wxt@rock-chips.com>
7  */
8 
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/device.h>
12 #include <linux/io.h>
13 #include <linux/module.h>
14 #include <linux/nvmem-provider.h>
15 #include <linux/slab.h>
16 #include <linux/of.h>
17 #include <linux/of_platform.h>
18 #include <linux/platform_device.h>
19 
20 #define RK3288_A_SHIFT		6
21 #define RK3288_A_MASK		0x3ff
22 #define RK3288_PGENB		BIT(3)
23 #define RK3288_LOAD		BIT(2)
24 #define RK3288_STROBE		BIT(1)
25 #define RK3288_CSB		BIT(0)
26 
27 #define RK3328_SECURE_SIZES	96
28 #define RK3328_INT_STATUS	0x0018
29 #define RK3328_DOUT		0x0020
30 #define RK3328_AUTO_CTRL	0x0024
31 #define RK3328_INT_FINISH	BIT(0)
32 #define RK3328_AUTO_ENB		BIT(0)
33 #define RK3328_AUTO_RD		BIT(1)
34 
35 #define RK3399_A_SHIFT		16
36 #define RK3399_A_MASK		0x3ff
37 #define RK3399_NBYTES		4
38 #define RK3399_STROBSFTSEL	BIT(9)
39 #define RK3399_RSB		BIT(7)
40 #define RK3399_PD		BIT(5)
41 #define RK3399_PGENB		BIT(3)
42 #define RK3399_LOAD		BIT(2)
43 #define RK3399_STROBE		BIT(1)
44 #define RK3399_CSB		BIT(0)
45 
46 #define REG_EFUSE_CTRL		0x0000
47 #define REG_EFUSE_DOUT		0x0004
48 
49 struct rockchip_efuse_chip {
50 	struct device *dev;
51 	void __iomem *base;
52 	struct clk *clk;
53 };
54 
55 static int rockchip_rk3288_efuse_read(void *context, unsigned int offset,
56 				      void *val, size_t bytes)
57 {
58 	struct rockchip_efuse_chip *efuse = context;
59 	u8 *buf = val;
60 	int ret;
61 
62 	ret = clk_prepare_enable(efuse->clk);
63 	if (ret < 0) {
64 		dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
65 		return ret;
66 	}
67 
68 	writel(RK3288_LOAD | RK3288_PGENB, efuse->base + REG_EFUSE_CTRL);
69 	udelay(1);
70 	while (bytes--) {
71 		writel(readl(efuse->base + REG_EFUSE_CTRL) &
72 			     (~(RK3288_A_MASK << RK3288_A_SHIFT)),
73 			     efuse->base + REG_EFUSE_CTRL);
74 		writel(readl(efuse->base + REG_EFUSE_CTRL) |
75 			     ((offset++ & RK3288_A_MASK) << RK3288_A_SHIFT),
76 			     efuse->base + REG_EFUSE_CTRL);
77 		udelay(1);
78 		writel(readl(efuse->base + REG_EFUSE_CTRL) |
79 			     RK3288_STROBE, efuse->base + REG_EFUSE_CTRL);
80 		udelay(1);
81 		*buf++ = readb(efuse->base + REG_EFUSE_DOUT);
82 		writel(readl(efuse->base + REG_EFUSE_CTRL) &
83 		       (~RK3288_STROBE), efuse->base + REG_EFUSE_CTRL);
84 		udelay(1);
85 	}
86 
87 	/* Switch to standby mode */
88 	writel(RK3288_PGENB | RK3288_CSB, efuse->base + REG_EFUSE_CTRL);
89 
90 	clk_disable_unprepare(efuse->clk);
91 
92 	return 0;
93 }
94 
95 static int rockchip_rk3328_efuse_read(void *context, unsigned int offset,
96 				      void *val, size_t bytes)
97 {
98 	struct rockchip_efuse_chip *efuse = context;
99 	unsigned int addr_start, addr_end, addr_offset, addr_len;
100 	u32 out_value, status;
101 	u8 *buf;
102 	int ret, i = 0;
103 
104 	ret = clk_prepare_enable(efuse->clk);
105 	if (ret < 0) {
106 		dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
107 		return ret;
108 	}
109 
110 	/* 128 Byte efuse, 96 Byte for secure, 32 Byte for non-secure */
111 	offset += RK3328_SECURE_SIZES;
112 	addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
113 	addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
114 	addr_offset = offset % RK3399_NBYTES;
115 	addr_len = addr_end - addr_start;
116 
117 	buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
118 		      GFP_KERNEL);
119 	if (!buf) {
120 		ret = -ENOMEM;
121 		goto nomem;
122 	}
123 
124 	while (addr_len--) {
125 		writel(RK3328_AUTO_RD | RK3328_AUTO_ENB |
126 		       ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
127 		       efuse->base + RK3328_AUTO_CTRL);
128 		udelay(4);
129 		status = readl(efuse->base + RK3328_INT_STATUS);
130 		if (!(status & RK3328_INT_FINISH)) {
131 			ret = -EIO;
132 			goto err;
133 		}
134 		out_value = readl(efuse->base + RK3328_DOUT);
135 		writel(RK3328_INT_FINISH, efuse->base + RK3328_INT_STATUS);
136 
137 		memcpy(&buf[i], &out_value, RK3399_NBYTES);
138 		i += RK3399_NBYTES;
139 	}
140 
141 	memcpy(val, buf + addr_offset, bytes);
142 err:
143 	kfree(buf);
144 nomem:
145 	clk_disable_unprepare(efuse->clk);
146 
147 	return ret;
148 }
149 
150 static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
151 				      void *val, size_t bytes)
152 {
153 	struct rockchip_efuse_chip *efuse = context;
154 	unsigned int addr_start, addr_end, addr_offset, addr_len;
155 	u32 out_value;
156 	u8 *buf;
157 	int ret, i = 0;
158 
159 	ret = clk_prepare_enable(efuse->clk);
160 	if (ret < 0) {
161 		dev_err(efuse->dev, "failed to prepare/enable efuse clk\n");
162 		return ret;
163 	}
164 
165 	addr_start = rounddown(offset, RK3399_NBYTES) / RK3399_NBYTES;
166 	addr_end = roundup(offset + bytes, RK3399_NBYTES) / RK3399_NBYTES;
167 	addr_offset = offset % RK3399_NBYTES;
168 	addr_len = addr_end - addr_start;
169 
170 	buf = kzalloc(array3_size(addr_len, RK3399_NBYTES, sizeof(*buf)),
171 		      GFP_KERNEL);
172 	if (!buf) {
173 		clk_disable_unprepare(efuse->clk);
174 		return -ENOMEM;
175 	}
176 
177 	writel(RK3399_LOAD | RK3399_PGENB | RK3399_STROBSFTSEL | RK3399_RSB,
178 	       efuse->base + REG_EFUSE_CTRL);
179 	udelay(1);
180 	while (addr_len--) {
181 		writel(readl(efuse->base + REG_EFUSE_CTRL) | RK3399_STROBE |
182 		       ((addr_start++ & RK3399_A_MASK) << RK3399_A_SHIFT),
183 		       efuse->base + REG_EFUSE_CTRL);
184 		udelay(1);
185 		out_value = readl(efuse->base + REG_EFUSE_DOUT);
186 		writel(readl(efuse->base + REG_EFUSE_CTRL) & (~RK3399_STROBE),
187 		       efuse->base + REG_EFUSE_CTRL);
188 		udelay(1);
189 
190 		memcpy(&buf[i], &out_value, RK3399_NBYTES);
191 		i += RK3399_NBYTES;
192 	}
193 
194 	/* Switch to standby mode */
195 	writel(RK3399_PD | RK3399_CSB, efuse->base + REG_EFUSE_CTRL);
196 
197 	memcpy(val, buf + addr_offset, bytes);
198 
199 	kfree(buf);
200 
201 	clk_disable_unprepare(efuse->clk);
202 
203 	return 0;
204 }
205 
206 static struct nvmem_config econfig = {
207 	.name = "rockchip-efuse",
208 	.add_legacy_fixed_of_cells = true,
209 	.stride = 1,
210 	.word_size = 1,
211 	.read_only = true,
212 };
213 
214 static const struct of_device_id rockchip_efuse_match[] = {
215 	/* deprecated but kept around for dts binding compatibility */
216 	{
217 		.compatible = "rockchip,rockchip-efuse",
218 		.data = (void *)&rockchip_rk3288_efuse_read,
219 	},
220 	{
221 		.compatible = "rockchip,rk3066a-efuse",
222 		.data = (void *)&rockchip_rk3288_efuse_read,
223 	},
224 	{
225 		.compatible = "rockchip,rk3188-efuse",
226 		.data = (void *)&rockchip_rk3288_efuse_read,
227 	},
228 	{
229 		.compatible = "rockchip,rk3228-efuse",
230 		.data = (void *)&rockchip_rk3288_efuse_read,
231 	},
232 	{
233 		.compatible = "rockchip,rk3288-efuse",
234 		.data = (void *)&rockchip_rk3288_efuse_read,
235 	},
236 	{
237 		.compatible = "rockchip,rk3368-efuse",
238 		.data = (void *)&rockchip_rk3288_efuse_read,
239 	},
240 	{
241 		.compatible = "rockchip,rk3328-efuse",
242 		.data = (void *)&rockchip_rk3328_efuse_read,
243 	},
244 	{
245 		.compatible = "rockchip,rk3399-efuse",
246 		.data = (void *)&rockchip_rk3399_efuse_read,
247 	},
248 	{ /* sentinel */},
249 };
250 MODULE_DEVICE_TABLE(of, rockchip_efuse_match);
251 
252 static int rockchip_efuse_probe(struct platform_device *pdev)
253 {
254 	struct resource *res;
255 	struct nvmem_device *nvmem;
256 	struct rockchip_efuse_chip *efuse;
257 	const void *data;
258 	struct device *dev = &pdev->dev;
259 
260 	data = of_device_get_match_data(dev);
261 	if (!data) {
262 		dev_err(dev, "failed to get match data\n");
263 		return -EINVAL;
264 	}
265 
266 	efuse = devm_kzalloc(dev, sizeof(struct rockchip_efuse_chip),
267 			     GFP_KERNEL);
268 	if (!efuse)
269 		return -ENOMEM;
270 
271 	efuse->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
272 	if (IS_ERR(efuse->base))
273 		return PTR_ERR(efuse->base);
274 
275 	efuse->clk = devm_clk_get(dev, "pclk_efuse");
276 	if (IS_ERR(efuse->clk))
277 		return PTR_ERR(efuse->clk);
278 
279 	efuse->dev = dev;
280 	if (of_property_read_u32(dev->of_node, "rockchip,efuse-size",
281 				 &econfig.size))
282 		econfig.size = resource_size(res);
283 	econfig.reg_read = data;
284 	econfig.priv = efuse;
285 	econfig.dev = efuse->dev;
286 	nvmem = devm_nvmem_register(dev, &econfig);
287 
288 	return PTR_ERR_OR_ZERO(nvmem);
289 }
290 
291 static struct platform_driver rockchip_efuse_driver = {
292 	.probe = rockchip_efuse_probe,
293 	.driver = {
294 		.name = "rockchip-efuse",
295 		.of_match_table = rockchip_efuse_match,
296 	},
297 };
298 
299 module_platform_driver(rockchip_efuse_driver);
300 MODULE_DESCRIPTION("rockchip_efuse driver");
301 MODULE_LICENSE("GPL v2");
302