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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
29struct sunxi_sid_cfg {
30 u32 value_offset;
31 u32 size;
32 bool need_register_readout;
33};
34
35struct sunxi_sid {
36 void __iomem *base;
37 u32 value_offset;
38};
39
40static 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
63static 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 */
94static 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
125static 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
186static const struct sunxi_sid_cfg sun4i_a10_cfg = {
187 .size = 0x10,
188};
189
190static const struct sunxi_sid_cfg sun7i_a20_cfg = {
191 .size = 0x200,
192};
193
194static const struct sunxi_sid_cfg sun8i_h3_cfg = {
195 .value_offset = 0x200,
196 .size = 0x100,
197 .need_register_readout = true,
198};
199
200static const struct sunxi_sid_cfg sun20i_d1_cfg = {
201 .value_offset = 0x200,
202 .size = 0x100,
203};
204
205static const struct sunxi_sid_cfg sun50i_a64_cfg = {
206 .value_offset = 0x200,
207 .size = 0x100,
208 .need_register_readout = true,
209};
210
211static const struct sunxi_sid_cfg sun50i_h6_cfg = {
212 .value_offset = 0x200,
213 .size = 0x200,
214};
215
216static 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};
227MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
228
229static 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};
236module_platform_driver(sunxi_sid_driver);
237
238MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
239MODULE_DESCRIPTION("Allwinner sunxi security id driver");
240MODULE_LICENSE("GPL");
1/*
2 * Allwinner sunXi SoCs Security ID support.
3 *
4 * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
5 * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 */
17
18#include <linux/device.h>
19#include <linux/io.h>
20#include <linux/module.h>
21#include <linux/nvmem-provider.h>
22#include <linux/of.h>
23#include <linux/platform_device.h>
24#include <linux/regmap.h>
25#include <linux/slab.h>
26#include <linux/random.h>
27
28static struct nvmem_config econfig = {
29 .name = "sunxi-sid",
30 .read_only = true,
31 .owner = THIS_MODULE,
32};
33
34struct sunxi_sid {
35 void __iomem *base;
36};
37
38/* We read the entire key, due to a 32 bit read alignment requirement. Since we
39 * want to return the requested byte, this results in somewhat slower code and
40 * uses 4 times more reads as needed but keeps code simpler. Since the SID is
41 * only very rarely probed, this is not really an issue.
42 */
43static u8 sunxi_sid_read_byte(const struct sunxi_sid *sid,
44 const unsigned int offset)
45{
46 u32 sid_key;
47
48 sid_key = ioread32be(sid->base + round_down(offset, 4));
49 sid_key >>= (offset % 4) * 8;
50
51 return sid_key; /* Only return the last byte */
52}
53
54static int sunxi_sid_read(void *context,
55 const void *reg, size_t reg_size,
56 void *val, size_t val_size)
57{
58 struct sunxi_sid *sid = context;
59 unsigned int offset = *(u32 *)reg;
60 u8 *buf = val;
61
62 while (val_size) {
63 *buf++ = sunxi_sid_read_byte(sid, offset);
64 val_size--;
65 offset++;
66 }
67
68 return 0;
69}
70
71static int sunxi_sid_write(void *context, const void *data, size_t count)
72{
73 /* Unimplemented, dummy to keep regmap core happy */
74 return 0;
75}
76
77static struct regmap_bus sunxi_sid_bus = {
78 .read = sunxi_sid_read,
79 .write = sunxi_sid_write,
80 .reg_format_endian_default = REGMAP_ENDIAN_NATIVE,
81 .val_format_endian_default = REGMAP_ENDIAN_NATIVE,
82};
83
84static bool sunxi_sid_writeable_reg(struct device *dev, unsigned int reg)
85{
86 return false;
87}
88
89static struct regmap_config sunxi_sid_regmap_config = {
90 .reg_bits = 32,
91 .val_bits = 8,
92 .reg_stride = 1,
93 .writeable_reg = sunxi_sid_writeable_reg,
94};
95
96static int sunxi_sid_probe(struct platform_device *pdev)
97{
98 struct device *dev = &pdev->dev;
99 struct resource *res;
100 struct nvmem_device *nvmem;
101 struct regmap *regmap;
102 struct sunxi_sid *sid;
103 int ret, i, size;
104 char *randomness;
105
106 sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
107 if (!sid)
108 return -ENOMEM;
109
110 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
111 sid->base = devm_ioremap_resource(dev, res);
112 if (IS_ERR(sid->base))
113 return PTR_ERR(sid->base);
114
115 size = resource_size(res) - 1;
116 sunxi_sid_regmap_config.max_register = size;
117
118 regmap = devm_regmap_init(dev, &sunxi_sid_bus, sid,
119 &sunxi_sid_regmap_config);
120 if (IS_ERR(regmap)) {
121 dev_err(dev, "regmap init failed\n");
122 return PTR_ERR(regmap);
123 }
124
125 econfig.dev = dev;
126 nvmem = nvmem_register(&econfig);
127 if (IS_ERR(nvmem))
128 return PTR_ERR(nvmem);
129
130 randomness = kzalloc(sizeof(u8) * (size), GFP_KERNEL);
131 if (!randomness) {
132 ret = -EINVAL;
133 goto err_unreg_nvmem;
134 }
135
136 for (i = 0; i < size; i++)
137 randomness[i] = sunxi_sid_read_byte(sid, i);
138
139 add_device_randomness(randomness, size);
140 kfree(randomness);
141
142 platform_set_drvdata(pdev, nvmem);
143
144 return 0;
145
146err_unreg_nvmem:
147 nvmem_unregister(nvmem);
148 return ret;
149}
150
151static int sunxi_sid_remove(struct platform_device *pdev)
152{
153 struct nvmem_device *nvmem = platform_get_drvdata(pdev);
154
155 return nvmem_unregister(nvmem);
156}
157
158static const struct of_device_id sunxi_sid_of_match[] = {
159 { .compatible = "allwinner,sun4i-a10-sid" },
160 { .compatible = "allwinner,sun7i-a20-sid" },
161 {/* sentinel */},
162};
163MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
164
165static struct platform_driver sunxi_sid_driver = {
166 .probe = sunxi_sid_probe,
167 .remove = sunxi_sid_remove,
168 .driver = {
169 .name = "eeprom-sunxi-sid",
170 .of_match_table = sunxi_sid_of_match,
171 },
172};
173module_platform_driver(sunxi_sid_driver);
174
175MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
176MODULE_DESCRIPTION("Allwinner sunxi security id driver");
177MODULE_LICENSE("GPL");