GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / nvmem / sunxi_sid.c
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
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
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  */
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
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 sun20i_d1_cfg = {
188         .value_offset = 0x200,
189         .size = 0x100,
190 };
191
192 static const struct sunxi_sid_cfg sun50i_a64_cfg = {
193         .value_offset = 0x200,
194         .size = 0x100,
195         .need_register_readout = true,
196 };
197
198 static const struct sunxi_sid_cfg sun50i_h6_cfg = {
199         .value_offset = 0x200,
200         .size = 0x200,
201 };
202
203 static const struct of_device_id sunxi_sid_of_match[] = {
204         { .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
205         { .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
206         { .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg },
207         { .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
208         { .compatible = "allwinner,sun20i-d1-sid", .data = &sun20i_d1_cfg },
209         { .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg },
210         { .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg },
211         { .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg },
212         {/* sentinel */},
213 };
214 MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
215
216 static struct platform_driver sunxi_sid_driver = {
217         .probe = sunxi_sid_probe,
218         .driver = {
219                 .name = "eeprom-sunxi-sid",
220                 .of_match_table = sunxi_sid_of_match,
221         },
222 };
223 module_platform_driver(sunxi_sid_driver);
224
225 MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
226 MODULE_DESCRIPTION("Allwinner sunxi security id driver");
227 MODULE_LICENSE("GPL");