1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Allwinner sunXi SoCs Security ID support.
4 *
5 * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
6 * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
7 */
8
9 #include <linux/device.h>
10 #include <linux/io.h>
11 #include <linux/iopoll.h>
12 #include <linux/module.h>
13 #include <linux/nvmem-provider.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/platform_device.h>
17 #include <linux/slab.h>
18 #include <linux/random.h>
19
20 /* Registers and special values for doing register-based SID readout on H3 */
21 #define SUN8I_SID_PRCTL 0x40
22 #define SUN8I_SID_RDKEY 0x60
23
24 #define SUN8I_SID_OFFSET_MASK 0x1FF
25 #define SUN8I_SID_OFFSET_SHIFT 16
26 #define SUN8I_SID_OP_LOCK (0xAC << 8)
27 #define SUN8I_SID_READ BIT(1)
28
29 struct sunxi_sid_cfg {
30 u32 value_offset;
31 u32 size;
32 bool need_register_readout;
33 };
34
35 struct sunxi_sid {
36 void __iomem *base;
37 u32 value_offset;
38 };
39
sunxi_sid_read(void * context,unsigned int offset,void * val,size_t bytes)40 static int sunxi_sid_read(void *context, unsigned int offset,
41 void *val, size_t bytes)
42 {
43 struct sunxi_sid *sid = context;
44 u32 word;
45
46 /* .stride = 4 so offset is guaranteed to be aligned */
47 __ioread32_copy(val, sid->base + sid->value_offset + offset, bytes / 4);
48
49 val += round_down(bytes, 4);
50 offset += round_down(bytes, 4);
51 bytes = bytes % 4;
52
53 if (!bytes)
54 return 0;
55
56 /* Handle any trailing bytes */
57 word = readl_relaxed(sid->base + sid->value_offset + offset);
58 memcpy(val, &word, bytes);
59
60 return 0;
61 }
62
sun8i_sid_register_readout(const struct sunxi_sid * sid,const unsigned int offset,u32 * out)63 static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
64 const unsigned int offset,
65 u32 *out)
66 {
67 u32 reg_val;
68 int ret;
69
70 /* Set word, lock access, and set read command */
71 reg_val = (offset & SUN8I_SID_OFFSET_MASK)
72 << SUN8I_SID_OFFSET_SHIFT;
73 reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ;
74 writel(reg_val, sid->base + SUN8I_SID_PRCTL);
75
76 ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val,
77 !(reg_val & SUN8I_SID_READ), 100, 250000);
78 if (ret)
79 return ret;
80
81 if (out)
82 *out = readl(sid->base + SUN8I_SID_RDKEY);
83
84 writel(0, sid->base + SUN8I_SID_PRCTL);
85
86 return 0;
87 }
88
89 /*
90 * On Allwinner H3, the value on the 0x200 offset of the SID controller seems
91 * to be not reliable at all.
92 * Read by the registers instead.
93 */
sun8i_sid_read_by_reg(void * context,unsigned int offset,void * val,size_t bytes)94 static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
95 void *val, size_t bytes)
96 {
97 struct sunxi_sid *sid = context;
98 u32 word;
99 int ret;
100
101 /* .stride = 4 so offset is guaranteed to be aligned */
102 while (bytes >= 4) {
103 ret = sun8i_sid_register_readout(sid, offset, val);
104 if (ret)
105 return ret;
106
107 val += 4;
108 offset += 4;
109 bytes -= 4;
110 }
111
112 if (!bytes)
113 return 0;
114
115 /* Handle any trailing bytes */
116 ret = sun8i_sid_register_readout(sid, offset, &word);
117 if (ret)
118 return ret;
119
120 memcpy(val, &word, bytes);
121
122 return 0;
123 }
124
sunxi_sid_probe(struct platform_device * pdev)125 static int sunxi_sid_probe(struct platform_device *pdev)
126 {
127 struct device *dev = &pdev->dev;
128 struct resource *res;
129 struct nvmem_config *nvmem_cfg;
130 struct nvmem_device *nvmem;
131 struct sunxi_sid *sid;
132 int size;
133 char *randomness;
134 const struct sunxi_sid_cfg *cfg;
135
136 sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
137 if (!sid)
138 return -ENOMEM;
139
140 cfg = of_device_get_match_data(dev);
141 if (!cfg)
142 return -EINVAL;
143 sid->value_offset = cfg->value_offset;
144
145 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
146 sid->base = devm_ioremap_resource(dev, res);
147 if (IS_ERR(sid->base))
148 return PTR_ERR(sid->base);
149
150 size = cfg->size;
151
152 nvmem_cfg = devm_kzalloc(dev, sizeof(*nvmem_cfg), GFP_KERNEL);
153 if (!nvmem_cfg)
154 return -ENOMEM;
155
156 nvmem_cfg->dev = dev;
157 nvmem_cfg->name = "sunxi-sid";
158 nvmem_cfg->type = NVMEM_TYPE_OTP;
159 nvmem_cfg->read_only = true;
160 nvmem_cfg->size = cfg->size;
161 nvmem_cfg->word_size = 1;
162 nvmem_cfg->stride = 4;
163 nvmem_cfg->priv = sid;
164 if (cfg->need_register_readout)
165 nvmem_cfg->reg_read = sun8i_sid_read_by_reg;
166 else
167 nvmem_cfg->reg_read = sunxi_sid_read;
168
169 nvmem = devm_nvmem_register(dev, nvmem_cfg);
170 if (IS_ERR(nvmem))
171 return PTR_ERR(nvmem);
172
173 randomness = kzalloc(size, GFP_KERNEL);
174 if (!randomness)
175 return -ENOMEM;
176
177 nvmem_cfg->reg_read(sid, 0, randomness, size);
178 add_device_randomness(randomness, size);
179 kfree(randomness);
180
181 platform_set_drvdata(pdev, nvmem);
182
183 return 0;
184 }
185
186 static const struct sunxi_sid_cfg sun4i_a10_cfg = {
187 .size = 0x10,
188 };
189
190 static const struct sunxi_sid_cfg sun7i_a20_cfg = {
191 .size = 0x200,
192 };
193
194 static const struct sunxi_sid_cfg sun8i_h3_cfg = {
195 .value_offset = 0x200,
196 .size = 0x100,
197 .need_register_readout = true,
198 };
199
200 static const struct sunxi_sid_cfg sun20i_d1_cfg = {
201 .value_offset = 0x200,
202 .size = 0x100,
203 };
204
205 static const struct sunxi_sid_cfg sun50i_a64_cfg = {
206 .value_offset = 0x200,
207 .size = 0x100,
208 .need_register_readout = true,
209 };
210
211 static const struct sunxi_sid_cfg sun50i_h6_cfg = {
212 .value_offset = 0x200,
213 .size = 0x200,
214 };
215
216 static const struct of_device_id sunxi_sid_of_match[] = {
217 { .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
218 { .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
219 { .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg },
220 { .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
221 { .compatible = "allwinner,sun20i-d1-sid", .data = &sun20i_d1_cfg },
222 { .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg },
223 { .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg },
224 { .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg },
225 {/* sentinel */},
226 };
227 MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
228
229 static struct platform_driver sunxi_sid_driver = {
230 .probe = sunxi_sid_probe,
231 .driver = {
232 .name = "eeprom-sunxi-sid",
233 .of_match_table = sunxi_sid_of_match,
234 },
235 };
236 module_platform_driver(sunxi_sid_driver);
237
238 MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
239 MODULE_DESCRIPTION("Allwinner sunxi security id driver");
240 MODULE_LICENSE("GPL");
241