Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * STM32 Factory-programmed memory read access driver
4 *
5 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
6 * Author: Fabrice Gasnier <fabrice.gasnier@st.com> for STMicroelectronics.
7 */
8
9#include <linux/arm-smccc.h>
10#include <linux/io.h>
11#include <linux/module.h>
12#include <linux/nvmem-provider.h>
13#include <linux/of_device.h>
14
15/* BSEC secure service access from non-secure */
16#define STM32_SMC_BSEC 0x82001003
17#define STM32_SMC_READ_SHADOW 0x01
18#define STM32_SMC_PROG_OTP 0x02
19#define STM32_SMC_WRITE_SHADOW 0x03
20#define STM32_SMC_READ_OTP 0x04
21
22/* shadow registers offest */
23#define STM32MP15_BSEC_DATA0 0x200
24
25/* 32 (x 32-bits) lower shadow registers */
26#define STM32MP15_BSEC_NUM_LOWER 32
27
28struct stm32_romem_cfg {
29 int size;
30};
31
32struct stm32_romem_priv {
33 void __iomem *base;
34 struct nvmem_config cfg;
35};
36
37static int stm32_romem_read(void *context, unsigned int offset, void *buf,
38 size_t bytes)
39{
40 struct stm32_romem_priv *priv = context;
41 u8 *buf8 = buf;
42 int i;
43
44 for (i = offset; i < offset + bytes; i++)
45 *buf8++ = readb_relaxed(priv->base + i);
46
47 return 0;
48}
49
50static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)
51{
52#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC)
53 struct arm_smccc_res res;
54
55 arm_smccc_smc(STM32_SMC_BSEC, op, otp, data, 0, 0, 0, 0, &res);
56 if (res.a0)
57 return -EIO;
58
59 if (result)
60 *result = (u32)res.a1;
61
62 return 0;
63#else
64 return -ENXIO;
65#endif
66}
67
68static int stm32_bsec_read(void *context, unsigned int offset, void *buf,
69 size_t bytes)
70{
71 struct stm32_romem_priv *priv = context;
72 struct device *dev = priv->cfg.dev;
73 u32 roffset, rbytes, val;
74 u8 *buf8 = buf, *val8 = (u8 *)&val;
75 int i, j = 0, ret, skip_bytes, size;
76
77 /* Round unaligned access to 32-bits */
78 roffset = rounddown(offset, 4);
79 skip_bytes = offset & 0x3;
80 rbytes = roundup(bytes + skip_bytes, 4);
81
82 if (roffset + rbytes > priv->cfg.size)
83 return -EINVAL;
84
85 for (i = roffset; (i < roffset + rbytes); i += 4) {
86 u32 otp = i >> 2;
87
88 if (otp < STM32MP15_BSEC_NUM_LOWER) {
89 /* read lower data from shadow registers */
90 val = readl_relaxed(
91 priv->base + STM32MP15_BSEC_DATA0 + i);
92 } else {
93 ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, otp, 0,
94 &val);
95 if (ret) {
96 dev_err(dev, "Can't read data%d (%d)\n", otp,
97 ret);
98 return ret;
99 }
100 }
101 /* skip first bytes in case of unaligned read */
102 if (skip_bytes)
103 size = min(bytes, (size_t)(4 - skip_bytes));
104 else
105 size = min(bytes, (size_t)4);
106 memcpy(&buf8[j], &val8[skip_bytes], size);
107 bytes -= size;
108 j += size;
109 skip_bytes = 0;
110 }
111
112 return 0;
113}
114
115static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
116 size_t bytes)
117{
118 struct stm32_romem_priv *priv = context;
119 struct device *dev = priv->cfg.dev;
120 u32 *buf32 = buf;
121 int ret, i;
122
123 /* Allow only writing complete 32-bits aligned words */
124 if ((bytes % 4) || (offset % 4))
125 return -EINVAL;
126
127 for (i = offset; i < offset + bytes; i += 4) {
128 ret = stm32_bsec_smc(STM32_SMC_PROG_OTP, i >> 2, *buf32++,
129 NULL);
130 if (ret) {
131 dev_err(dev, "Can't write data%d (%d)\n", i >> 2, ret);
132 return ret;
133 }
134 }
135
136 return 0;
137}
138
139static int stm32_romem_probe(struct platform_device *pdev)
140{
141 const struct stm32_romem_cfg *cfg;
142 struct device *dev = &pdev->dev;
143 struct stm32_romem_priv *priv;
144 struct resource *res;
145
146 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
147 if (!priv)
148 return -ENOMEM;
149
150 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
151 priv->base = devm_ioremap_resource(dev, res);
152 if (IS_ERR(priv->base))
153 return PTR_ERR(priv->base);
154
155 priv->cfg.name = "stm32-romem";
156 priv->cfg.word_size = 1;
157 priv->cfg.stride = 1;
158 priv->cfg.dev = dev;
159 priv->cfg.priv = priv;
160 priv->cfg.owner = THIS_MODULE;
161
162 cfg = (const struct stm32_romem_cfg *)
163 of_match_device(dev->driver->of_match_table, dev)->data;
164 if (!cfg) {
165 priv->cfg.read_only = true;
166 priv->cfg.size = resource_size(res);
167 priv->cfg.reg_read = stm32_romem_read;
168 } else {
169 priv->cfg.size = cfg->size;
170 priv->cfg.reg_read = stm32_bsec_read;
171 priv->cfg.reg_write = stm32_bsec_write;
172 }
173
174 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
175}
176
177static const struct stm32_romem_cfg stm32mp15_bsec_cfg = {
178 .size = 384, /* 96 x 32-bits data words */
179};
180
181static const struct of_device_id stm32_romem_of_match[] = {
182 { .compatible = "st,stm32f4-otp", }, {
183 .compatible = "st,stm32mp15-bsec",
184 .data = (void *)&stm32mp15_bsec_cfg,
185 }, {
186 },
187};
188MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
189
190static struct platform_driver stm32_romem_driver = {
191 .probe = stm32_romem_probe,
192 .driver = {
193 .name = "stm32-romem",
194 .of_match_table = of_match_ptr(stm32_romem_of_match),
195 },
196};
197module_platform_driver(stm32_romem_driver);
198
199MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
200MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
201MODULE_ALIAS("platform:nvmem-stm32-romem");
202MODULE_LICENSE("GPL v2");
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * STM32 Factory-programmed memory read access driver
4 *
5 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
6 * Author: Fabrice Gasnier <fabrice.gasnier@st.com> for STMicroelectronics.
7 */
8
9#include <linux/arm-smccc.h>
10#include <linux/io.h>
11#include <linux/module.h>
12#include <linux/nvmem-provider.h>
13#include <linux/of.h>
14#include <linux/platform_device.h>
15#include <linux/property.h>
16#include <linux/tee_drv.h>
17
18#include "stm32-bsec-optee-ta.h"
19
20/* BSEC secure service access from non-secure */
21#define STM32_SMC_BSEC 0x82001003
22#define STM32_SMC_READ_SHADOW 0x01
23#define STM32_SMC_PROG_OTP 0x02
24#define STM32_SMC_WRITE_SHADOW 0x03
25#define STM32_SMC_READ_OTP 0x04
26
27/* shadow registers offset */
28#define STM32MP15_BSEC_DATA0 0x200
29
30struct stm32_romem_cfg {
31 int size;
32 u8 lower;
33 bool ta;
34};
35
36struct stm32_romem_priv {
37 void __iomem *base;
38 struct nvmem_config cfg;
39 u8 lower;
40 struct tee_context *ctx;
41};
42
43static int stm32_romem_read(void *context, unsigned int offset, void *buf,
44 size_t bytes)
45{
46 struct stm32_romem_priv *priv = context;
47 u8 *buf8 = buf;
48 int i;
49
50 for (i = offset; i < offset + bytes; i++)
51 *buf8++ = readb_relaxed(priv->base + i);
52
53 return 0;
54}
55
56static int stm32_bsec_smc(u8 op, u32 otp, u32 data, u32 *result)
57{
58#if IS_ENABLED(CONFIG_HAVE_ARM_SMCCC)
59 struct arm_smccc_res res;
60
61 arm_smccc_smc(STM32_SMC_BSEC, op, otp, data, 0, 0, 0, 0, &res);
62 if (res.a0)
63 return -EIO;
64
65 if (result)
66 *result = (u32)res.a1;
67
68 return 0;
69#else
70 return -ENXIO;
71#endif
72}
73
74static int stm32_bsec_read(void *context, unsigned int offset, void *buf,
75 size_t bytes)
76{
77 struct stm32_romem_priv *priv = context;
78 struct device *dev = priv->cfg.dev;
79 u32 roffset, rbytes, val;
80 u8 *buf8 = buf, *val8 = (u8 *)&val;
81 int i, j = 0, ret, skip_bytes, size;
82
83 /* Round unaligned access to 32-bits */
84 roffset = rounddown(offset, 4);
85 skip_bytes = offset & 0x3;
86 rbytes = roundup(bytes + skip_bytes, 4);
87
88 if (roffset + rbytes > priv->cfg.size)
89 return -EINVAL;
90
91 for (i = roffset; (i < roffset + rbytes); i += 4) {
92 u32 otp = i >> 2;
93
94 if (otp < priv->lower) {
95 /* read lower data from shadow registers */
96 val = readl_relaxed(
97 priv->base + STM32MP15_BSEC_DATA0 + i);
98 } else {
99 ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, otp, 0,
100 &val);
101 if (ret) {
102 dev_err(dev, "Can't read data%d (%d)\n", otp,
103 ret);
104 return ret;
105 }
106 }
107 /* skip first bytes in case of unaligned read */
108 if (skip_bytes)
109 size = min(bytes, (size_t)(4 - skip_bytes));
110 else
111 size = min(bytes, (size_t)4);
112 memcpy(&buf8[j], &val8[skip_bytes], size);
113 bytes -= size;
114 j += size;
115 skip_bytes = 0;
116 }
117
118 return 0;
119}
120
121static int stm32_bsec_write(void *context, unsigned int offset, void *buf,
122 size_t bytes)
123{
124 struct stm32_romem_priv *priv = context;
125 struct device *dev = priv->cfg.dev;
126 u32 *buf32 = buf;
127 int ret, i;
128
129 /* Allow only writing complete 32-bits aligned words */
130 if ((bytes % 4) || (offset % 4))
131 return -EINVAL;
132
133 for (i = offset; i < offset + bytes; i += 4) {
134 ret = stm32_bsec_smc(STM32_SMC_PROG_OTP, i >> 2, *buf32++,
135 NULL);
136 if (ret) {
137 dev_err(dev, "Can't write data%d (%d)\n", i >> 2, ret);
138 return ret;
139 }
140 }
141
142 if (offset + bytes >= priv->lower * 4)
143 dev_warn(dev, "Update of upper OTPs with ECC protection (word programming, only once)\n");
144
145 return 0;
146}
147
148static int stm32_bsec_pta_read(void *context, unsigned int offset, void *buf,
149 size_t bytes)
150{
151 struct stm32_romem_priv *priv = context;
152
153 return stm32_bsec_optee_ta_read(priv->ctx, offset, buf, bytes);
154}
155
156static int stm32_bsec_pta_write(void *context, unsigned int offset, void *buf,
157 size_t bytes)
158{
159 struct stm32_romem_priv *priv = context;
160
161 return stm32_bsec_optee_ta_write(priv->ctx, priv->lower, offset, buf, bytes);
162}
163
164static bool stm32_bsec_smc_check(void)
165{
166 u32 val;
167 int ret;
168
169 /* check that the OP-TEE support the BSEC SMC (legacy mode) */
170 ret = stm32_bsec_smc(STM32_SMC_READ_SHADOW, 0, 0, &val);
171
172 return !ret;
173}
174
175static bool optee_presence_check(void)
176{
177 struct device_node *np;
178 bool tee_detected = false;
179
180 /* check that the OP-TEE node is present and available. */
181 np = of_find_compatible_node(NULL, NULL, "linaro,optee-tz");
182 if (np && of_device_is_available(np))
183 tee_detected = true;
184 of_node_put(np);
185
186 return tee_detected;
187}
188
189static int stm32_romem_probe(struct platform_device *pdev)
190{
191 const struct stm32_romem_cfg *cfg;
192 struct device *dev = &pdev->dev;
193 struct stm32_romem_priv *priv;
194 struct resource *res;
195 int rc;
196
197 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
198 if (!priv)
199 return -ENOMEM;
200
201 priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
202 if (IS_ERR(priv->base))
203 return PTR_ERR(priv->base);
204
205 priv->cfg.name = "stm32-romem";
206 priv->cfg.word_size = 1;
207 priv->cfg.stride = 1;
208 priv->cfg.dev = dev;
209 priv->cfg.priv = priv;
210 priv->cfg.owner = THIS_MODULE;
211 priv->cfg.type = NVMEM_TYPE_OTP;
212 priv->cfg.add_legacy_fixed_of_cells = true;
213
214 priv->lower = 0;
215
216 cfg = device_get_match_data(dev);
217 if (!cfg) {
218 priv->cfg.read_only = true;
219 priv->cfg.size = resource_size(res);
220 priv->cfg.reg_read = stm32_romem_read;
221 } else {
222 priv->cfg.size = cfg->size;
223 priv->lower = cfg->lower;
224 if (cfg->ta || optee_presence_check()) {
225 rc = stm32_bsec_optee_ta_open(&priv->ctx);
226 if (rc) {
227 /* wait for OP-TEE client driver to be up and ready */
228 if (rc == -EPROBE_DEFER)
229 return -EPROBE_DEFER;
230 /* BSEC PTA is required or SMC not supported */
231 if (cfg->ta || !stm32_bsec_smc_check())
232 return rc;
233 }
234 }
235 if (priv->ctx) {
236 rc = devm_add_action_or_reset(dev, stm32_bsec_optee_ta_close, priv->ctx);
237 if (rc) {
238 dev_err(dev, "devm_add_action_or_reset() failed (%d)\n", rc);
239 return rc;
240 }
241 priv->cfg.reg_read = stm32_bsec_pta_read;
242 priv->cfg.reg_write = stm32_bsec_pta_write;
243 } else {
244 priv->cfg.reg_read = stm32_bsec_read;
245 priv->cfg.reg_write = stm32_bsec_write;
246 }
247 }
248
249 return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &priv->cfg));
250}
251
252/*
253 * STM32MP15/13 BSEC OTP regions: 4096 OTP bits (with 3072 effective bits)
254 * => 96 x 32-bits data words
255 * - Lower: 1K bits, 2:1 redundancy, incremental bit programming
256 * => 32 (x 32-bits) lower shadow registers = words 0 to 31
257 * - Upper: 2K bits, ECC protection, word programming only
258 * => 64 (x 32-bits) = words 32 to 95
259 */
260static const struct stm32_romem_cfg stm32mp15_bsec_cfg = {
261 .size = 384,
262 .lower = 32,
263 .ta = false,
264};
265
266static const struct stm32_romem_cfg stm32mp13_bsec_cfg = {
267 .size = 384,
268 .lower = 32,
269 .ta = true,
270};
271
272/*
273 * STM32MP25 BSEC OTP: 3 regions of 32-bits data words
274 * lower OTP (OTP0 to OTP127), bitwise (1-bit) programmable
275 * mid OTP (OTP128 to OTP255), bulk (32-bit) programmable
276 * upper OTP (OTP256 to OTP383), bulk (32-bit) programmable
277 * but no access to HWKEY and ECIES key: limited at OTP367
278 */
279static const struct stm32_romem_cfg stm32mp25_bsec_cfg = {
280 .size = 368 * 4,
281 .lower = 127,
282 .ta = true,
283};
284
285static const struct of_device_id stm32_romem_of_match[] __maybe_unused = {
286 { .compatible = "st,stm32f4-otp", }, {
287 .compatible = "st,stm32mp15-bsec",
288 .data = (void *)&stm32mp15_bsec_cfg,
289 }, {
290 .compatible = "st,stm32mp13-bsec",
291 .data = (void *)&stm32mp13_bsec_cfg,
292 }, {
293 .compatible = "st,stm32mp25-bsec",
294 .data = (void *)&stm32mp25_bsec_cfg,
295 },
296 { /* sentinel */ },
297};
298MODULE_DEVICE_TABLE(of, stm32_romem_of_match);
299
300static struct platform_driver stm32_romem_driver = {
301 .probe = stm32_romem_probe,
302 .driver = {
303 .name = "stm32-romem",
304 .of_match_table = of_match_ptr(stm32_romem_of_match),
305 },
306};
307module_platform_driver(stm32_romem_driver);
308
309MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
310MODULE_DESCRIPTION("STMicroelectronics STM32 RO-MEM");
311MODULE_ALIAS("platform:nvmem-stm32-romem");
312MODULE_LICENSE("GPL v2");