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
45 memcpy_fromio(val, sid->base + sid->value_offset + offset, bytes);
46
47 return 0;
48 }
49
sun8i_sid_register_readout(const struct sunxi_sid * sid,const unsigned int offset,u32 * out)50 static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
51 const unsigned int offset,
52 u32 *out)
53 {
54 u32 reg_val;
55 int ret;
56
57 /* Set word, lock access, and set read command */
58 reg_val = (offset & SUN8I_SID_OFFSET_MASK)
59 << SUN8I_SID_OFFSET_SHIFT;
60 reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ;
61 writel(reg_val, sid->base + SUN8I_SID_PRCTL);
62
63 ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val,
64 !(reg_val & SUN8I_SID_READ), 100, 250000);
65 if (ret)
66 return ret;
67
68 if (out)
69 *out = readl(sid->base + SUN8I_SID_RDKEY);
70
71 writel(0, sid->base + SUN8I_SID_PRCTL);
72
73 return 0;
74 }
75
76 /*
77 * On Allwinner H3, the value on the 0x200 offset of the SID controller seems
78 * to be not reliable at all.
79 * Read by the registers instead.
80 */
sun8i_sid_read_by_reg(void * context,unsigned int offset,void * val,size_t bytes)81 static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
82 void *val, size_t bytes)
83 {
84 struct sunxi_sid *sid = context;
85 u32 word;
86 int ret;
87
88 /* .stride = 4 so offset is guaranteed to be aligned */
89 while (bytes >= 4) {
90 ret = sun8i_sid_register_readout(sid, offset, val);
91 if (ret)
92 return ret;
93
94 val += 4;
95 offset += 4;
96 bytes -= 4;
97 }
98
99 if (!bytes)
100 return 0;
101
102 /* Handle any trailing bytes */
103 ret = sun8i_sid_register_readout(sid, offset, &word);
104 if (ret)
105 return ret;
106
107 memcpy(val, &word, bytes);
108
109 return 0;
110 }
111
sunxi_sid_probe(struct platform_device * pdev)112 static int sunxi_sid_probe(struct platform_device *pdev)
113 {
114 struct device *dev = &pdev->dev;
115 struct resource *res;
116 struct nvmem_config *nvmem_cfg;
117 struct nvmem_device *nvmem;
118 struct sunxi_sid *sid;
119 int size;
120 char *randomness;
121 const struct sunxi_sid_cfg *cfg;
122
123 sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
124 if (!sid)
125 return -ENOMEM;
126
127 cfg = of_device_get_match_data(dev);
128 if (!cfg)
129 return -EINVAL;
130 sid->value_offset = cfg->value_offset;
131
132 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
133 sid->base = devm_ioremap_resource(dev, res);
134 if (IS_ERR(sid->base))
135 return PTR_ERR(sid->base);
136
137 size = cfg->size;
138
139 nvmem_cfg = devm_kzalloc(dev, sizeof(*nvmem_cfg), GFP_KERNEL);
140 if (!nvmem_cfg)
141 return -ENOMEM;
142
143 nvmem_cfg->dev = dev;
144 nvmem_cfg->name = "sunxi-sid";
145 nvmem_cfg->type = NVMEM_TYPE_OTP;
146 nvmem_cfg->read_only = true;
147 nvmem_cfg->size = cfg->size;
148 nvmem_cfg->word_size = 1;
149 nvmem_cfg->stride = 4;
150 nvmem_cfg->priv = sid;
151 if (cfg->need_register_readout)
152 nvmem_cfg->reg_read = sun8i_sid_read_by_reg;
153 else
154 nvmem_cfg->reg_read = sunxi_sid_read;
155
156 nvmem = devm_nvmem_register(dev, nvmem_cfg);
157 if (IS_ERR(nvmem))
158 return PTR_ERR(nvmem);
159
160 randomness = kzalloc(size, GFP_KERNEL);
161 if (!randomness)
162 return -ENOMEM;
163
164 nvmem_cfg->reg_read(sid, 0, randomness, size);
165 add_device_randomness(randomness, size);
166 kfree(randomness);
167
168 platform_set_drvdata(pdev, nvmem);
169
170 return 0;
171 }
172
173 static const struct sunxi_sid_cfg sun4i_a10_cfg = {
174 .size = 0x10,
175 };
176
177 static const struct sunxi_sid_cfg sun7i_a20_cfg = {
178 .size = 0x200,
179 };
180
181 static const struct sunxi_sid_cfg sun8i_h3_cfg = {
182 .value_offset = 0x200,
183 .size = 0x100,
184 .need_register_readout = true,
185 };
186
187 static const struct sunxi_sid_cfg sun50i_a64_cfg = {
188 .value_offset = 0x200,
189 .size = 0x100,
190 .need_register_readout = true,
191 };
192
193 static const struct sunxi_sid_cfg sun50i_h6_cfg = {
194 .value_offset = 0x200,
195 .size = 0x200,
196 };
197
198 static const struct of_device_id sunxi_sid_of_match[] = {
199 { .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
200 { .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
201 { .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg },
202 { .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
203 { .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg },
204 { .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg },
205 { .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg },
206 {/* sentinel */},
207 };
208 MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
209
210 static struct platform_driver sunxi_sid_driver = {
211 .probe = sunxi_sid_probe,
212 .driver = {
213 .name = "eeprom-sunxi-sid",
214 .of_match_table = sunxi_sid_of_match,
215 },
216 };
217 module_platform_driver(sunxi_sid_driver);
218
219 MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
220 MODULE_DESCRIPTION("Allwinner sunxi security id driver");
221 MODULE_LICENSE("GPL");
222
