1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Amlogic Meson6, Meson8 and Meson8b eFuse Driver
4 *
5 * Copyright (c) 2017 Martin Blumenstingl <martin.blumenstingl@googlemail.com>
6 */
7
8 #include <linux/bitfield.h>
9 #include <linux/bitops.h>
10 #include <linux/clk.h>
11 #include <linux/delay.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/module.h>
15 #include <linux/nvmem-provider.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/sizes.h>
20 #include <linux/slab.h>
21
22 #define MESON_MX_EFUSE_CNTL1 0x04
23 #define MESON_MX_EFUSE_CNTL1_PD_ENABLE BIT(27)
24 #define MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY BIT(26)
25 #define MESON_MX_EFUSE_CNTL1_AUTO_RD_START BIT(25)
26 #define MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE BIT(24)
27 #define MESON_MX_EFUSE_CNTL1_BYTE_WR_DATA GENMASK(23, 16)
28 #define MESON_MX_EFUSE_CNTL1_AUTO_WR_BUSY BIT(14)
29 #define MESON_MX_EFUSE_CNTL1_AUTO_WR_START BIT(13)
30 #define MESON_MX_EFUSE_CNTL1_AUTO_WR_ENABLE BIT(12)
31 #define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET BIT(11)
32 #define MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK GENMASK(10, 0)
33
34 #define MESON_MX_EFUSE_CNTL2 0x08
35
36 #define MESON_MX_EFUSE_CNTL4 0x10
37 #define MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE BIT(10)
38
39 struct meson_mx_efuse_platform_data {
40 const char *name;
41 unsigned int word_size;
42 };
43
44 struct meson_mx_efuse {
45 void __iomem *base;
46 struct clk *core_clk;
47 struct nvmem_device *nvmem;
48 struct nvmem_config config;
49 };
50
meson_mx_efuse_mask_bits(struct meson_mx_efuse * efuse,u32 reg,u32 mask,u32 set)51 static void meson_mx_efuse_mask_bits(struct meson_mx_efuse *efuse, u32 reg,
52 u32 mask, u32 set)
53 {
54 u32 data;
55
56 data = readl(efuse->base + reg);
57 data &= ~mask;
58 data |= (set & mask);
59
60 writel(data, efuse->base + reg);
61 }
62
meson_mx_efuse_hw_enable(struct meson_mx_efuse * efuse)63 static int meson_mx_efuse_hw_enable(struct meson_mx_efuse *efuse)
64 {
65 int err;
66
67 err = clk_prepare_enable(efuse->core_clk);
68 if (err)
69 return err;
70
71 /* power up the efuse */
72 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
73 MESON_MX_EFUSE_CNTL1_PD_ENABLE, 0);
74
75 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL4,
76 MESON_MX_EFUSE_CNTL4_ENCRYPT_ENABLE, 0);
77
78 return 0;
79 }
80
meson_mx_efuse_hw_disable(struct meson_mx_efuse * efuse)81 static void meson_mx_efuse_hw_disable(struct meson_mx_efuse *efuse)
82 {
83 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
84 MESON_MX_EFUSE_CNTL1_PD_ENABLE,
85 MESON_MX_EFUSE_CNTL1_PD_ENABLE);
86
87 clk_disable_unprepare(efuse->core_clk);
88 }
89
meson_mx_efuse_read_addr(struct meson_mx_efuse * efuse,unsigned int addr,u32 * value)90 static int meson_mx_efuse_read_addr(struct meson_mx_efuse *efuse,
91 unsigned int addr, u32 *value)
92 {
93 int err;
94 u32 regval;
95
96 /* write the address to read */
97 regval = FIELD_PREP(MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, addr);
98 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
99 MESON_MX_EFUSE_CNTL1_BYTE_ADDR_MASK, regval);
100
101 /* inform the hardware that we changed the address */
102 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
103 MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET,
104 MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET);
105 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
106 MESON_MX_EFUSE_CNTL1_BYTE_ADDR_SET, 0);
107
108 /* start the read process */
109 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
110 MESON_MX_EFUSE_CNTL1_AUTO_RD_START,
111 MESON_MX_EFUSE_CNTL1_AUTO_RD_START);
112 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
113 MESON_MX_EFUSE_CNTL1_AUTO_RD_START, 0);
114
115 /*
116 * perform a dummy read to ensure that the HW has the RD_BUSY bit set
117 * when polling for the status below.
118 */
119 readl(efuse->base + MESON_MX_EFUSE_CNTL1);
120
121 err = readl_poll_timeout_atomic(efuse->base + MESON_MX_EFUSE_CNTL1,
122 regval,
123 (!(regval & MESON_MX_EFUSE_CNTL1_AUTO_RD_BUSY)),
124 1, 1000);
125 if (err) {
126 dev_err(efuse->config.dev,
127 "Timeout while reading efuse address %u\n", addr);
128 return err;
129 }
130
131 *value = readl(efuse->base + MESON_MX_EFUSE_CNTL2);
132
133 return 0;
134 }
135
meson_mx_efuse_read(void * context,unsigned int offset,void * buf,size_t bytes)136 static int meson_mx_efuse_read(void *context, unsigned int offset,
137 void *buf, size_t bytes)
138 {
139 struct meson_mx_efuse *efuse = context;
140 u32 tmp;
141 int err, i, addr;
142
143 err = meson_mx_efuse_hw_enable(efuse);
144 if (err)
145 return err;
146
147 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
148 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE,
149 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE);
150
151 for (i = 0; i < bytes; i += efuse->config.word_size) {
152 addr = (offset + i) / efuse->config.word_size;
153
154 err = meson_mx_efuse_read_addr(efuse, addr, &tmp);
155 if (err)
156 break;
157
158 memcpy(buf + i, &tmp,
159 min_t(size_t, bytes - i, efuse->config.word_size));
160 }
161
162 meson_mx_efuse_mask_bits(efuse, MESON_MX_EFUSE_CNTL1,
163 MESON_MX_EFUSE_CNTL1_AUTO_RD_ENABLE, 0);
164
165 meson_mx_efuse_hw_disable(efuse);
166
167 return err;
168 }
169
170 static const struct meson_mx_efuse_platform_data meson6_efuse_data = {
171 .name = "meson6-efuse",
172 .word_size = 1,
173 };
174
175 static const struct meson_mx_efuse_platform_data meson8_efuse_data = {
176 .name = "meson8-efuse",
177 .word_size = 4,
178 };
179
180 static const struct meson_mx_efuse_platform_data meson8b_efuse_data = {
181 .name = "meson8b-efuse",
182 .word_size = 4,
183 };
184
185 static const struct of_device_id meson_mx_efuse_match[] = {
186 { .compatible = "amlogic,meson6-efuse", .data = &meson6_efuse_data },
187 { .compatible = "amlogic,meson8-efuse", .data = &meson8_efuse_data },
188 { .compatible = "amlogic,meson8b-efuse", .data = &meson8b_efuse_data },
189 { /* sentinel */ },
190 };
191 MODULE_DEVICE_TABLE(of, meson_mx_efuse_match);
192
meson_mx_efuse_probe(struct platform_device * pdev)193 static int meson_mx_efuse_probe(struct platform_device *pdev)
194 {
195 const struct meson_mx_efuse_platform_data *drvdata;
196 struct meson_mx_efuse *efuse;
197 struct resource *res;
198
199 drvdata = of_device_get_match_data(&pdev->dev);
200 if (!drvdata)
201 return -EINVAL;
202
203 efuse = devm_kzalloc(&pdev->dev, sizeof(*efuse), GFP_KERNEL);
204 if (!efuse)
205 return -ENOMEM;
206
207 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
208 efuse->base = devm_ioremap_resource(&pdev->dev, res);
209 if (IS_ERR(efuse->base))
210 return PTR_ERR(efuse->base);
211
212 efuse->config.name = devm_kstrdup(&pdev->dev, drvdata->name,
213 GFP_KERNEL);
214 efuse->config.owner = THIS_MODULE;
215 efuse->config.dev = &pdev->dev;
216 efuse->config.priv = efuse;
217 efuse->config.stride = drvdata->word_size;
218 efuse->config.word_size = drvdata->word_size;
219 efuse->config.size = SZ_512;
220 efuse->config.read_only = true;
221 efuse->config.reg_read = meson_mx_efuse_read;
222
223 efuse->core_clk = devm_clk_get(&pdev->dev, "core");
224 if (IS_ERR(efuse->core_clk)) {
225 dev_err(&pdev->dev, "Failed to get core clock\n");
226 return PTR_ERR(efuse->core_clk);
227 }
228
229 efuse->nvmem = devm_nvmem_register(&pdev->dev, &efuse->config);
230
231 return PTR_ERR_OR_ZERO(efuse->nvmem);
232 }
233
234 static struct platform_driver meson_mx_efuse_driver = {
235 .probe = meson_mx_efuse_probe,
236 .driver = {
237 .name = "meson-mx-efuse",
238 .of_match_table = meson_mx_efuse_match,
239 },
240 };
241
242 module_platform_driver(meson_mx_efuse_driver);
243
244 MODULE_AUTHOR("Martin Blumenstingl <martin.blumenstingl@googlemail.com>");
245 MODULE_DESCRIPTION("Amlogic Meson MX eFuse NVMEM driver");
246 MODULE_LICENSE("GPL v2");
247