1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2019 HiSilicon Limited. */
3
4 #include <crypto/internal/rng.h>
5 #include <linux/acpi.h>
6 #include <linux/crypto.h>
7 #include <linux/err.h>
8 #include <linux/hw_random.h>
9 #include <linux/io.h>
10 #include <linux/iopoll.h>
11 #include <linux/kernel.h>
12 #include <linux/list.h>
13 #include <linux/module.h>
14 #include <linux/mutex.h>
15 #include <linux/platform_device.h>
16 #include <linux/random.h>
17
18 #define HISI_TRNG_REG 0x00F0
19 #define HISI_TRNG_BYTES 4
20 #define HISI_TRNG_QUALITY 512
21 #define HISI_TRNG_VERSION 0x01B8
22 #define HISI_TRNG_VER_V1 GENMASK(31, 0)
23 #define SLEEP_US 10
24 #define TIMEOUT_US 10000
25 #define SW_DRBG_NUM_SHIFT 2
26 #define SW_DRBG_KEY_BASE 0x082C
27 #define SW_DRBG_SEED(n) (SW_DRBG_KEY_BASE - ((n) << SW_DRBG_NUM_SHIFT))
28 #define SW_DRBG_SEED_REGS_NUM 12
29 #define SW_DRBG_SEED_SIZE 48
30 #define SW_DRBG_BLOCKS 0x0830
31 #define SW_DRBG_INIT 0x0834
32 #define SW_DRBG_GEN 0x083c
33 #define SW_DRBG_STATUS 0x0840
34 #define SW_DRBG_BLOCKS_NUM 4095
35 #define SW_DRBG_DATA_BASE 0x0850
36 #define SW_DRBG_DATA_NUM 4
37 #define SW_DRBG_DATA(n) (SW_DRBG_DATA_BASE - ((n) << SW_DRBG_NUM_SHIFT))
38 #define SW_DRBG_BYTES 16
39 #define SW_DRBG_ENABLE_SHIFT 12
40 #define SEED_SHIFT_24 24
41 #define SEED_SHIFT_16 16
42 #define SEED_SHIFT_8 8
43
44 struct hisi_trng_list {
45 struct mutex lock;
46 struct list_head list;
47 bool is_init;
48 };
49
50 struct hisi_trng {
51 void __iomem *base;
52 struct hisi_trng_list *trng_list;
53 struct list_head list;
54 struct hwrng rng;
55 u32 ver;
56 bool is_used;
57 struct mutex mutex;
58 };
59
60 struct hisi_trng_ctx {
61 struct hisi_trng *trng;
62 };
63
64 static atomic_t trng_active_devs;
65 static struct hisi_trng_list trng_devices;
66
hisi_trng_set_seed(struct hisi_trng * trng,const u8 * seed)67 static void hisi_trng_set_seed(struct hisi_trng *trng, const u8 *seed)
68 {
69 u32 val, seed_reg, i;
70
71 for (i = 0; i < SW_DRBG_SEED_SIZE;
72 i += SW_DRBG_SEED_SIZE / SW_DRBG_SEED_REGS_NUM) {
73 val = seed[i] << SEED_SHIFT_24;
74 val |= seed[i + 1UL] << SEED_SHIFT_16;
75 val |= seed[i + 2UL] << SEED_SHIFT_8;
76 val |= seed[i + 3UL];
77
78 seed_reg = (i >> SW_DRBG_NUM_SHIFT) % SW_DRBG_SEED_REGS_NUM;
79 writel(val, trng->base + SW_DRBG_SEED(seed_reg));
80 }
81 }
82
hisi_trng_seed(struct crypto_rng * tfm,const u8 * seed,unsigned int slen)83 static int hisi_trng_seed(struct crypto_rng *tfm, const u8 *seed,
84 unsigned int slen)
85 {
86 struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
87 struct hisi_trng *trng = ctx->trng;
88 u32 val = 0;
89 int ret = 0;
90
91 if (slen < SW_DRBG_SEED_SIZE) {
92 pr_err("slen(%u) is not matched with trng(%d)\n", slen,
93 SW_DRBG_SEED_SIZE);
94 return -EINVAL;
95 }
96
97 writel(0x0, trng->base + SW_DRBG_BLOCKS);
98 hisi_trng_set_seed(trng, seed);
99
100 writel(SW_DRBG_BLOCKS_NUM | (0x1 << SW_DRBG_ENABLE_SHIFT),
101 trng->base + SW_DRBG_BLOCKS);
102 writel(0x1, trng->base + SW_DRBG_INIT);
103
104 ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
105 val, val & BIT(0), SLEEP_US, TIMEOUT_US);
106 if (ret)
107 pr_err("fail to init trng(%d)\n", ret);
108
109 return ret;
110 }
111
hisi_trng_generate(struct crypto_rng * tfm,const u8 * src,unsigned int slen,u8 * dstn,unsigned int dlen)112 static int hisi_trng_generate(struct crypto_rng *tfm, const u8 *src,
113 unsigned int slen, u8 *dstn, unsigned int dlen)
114 {
115 struct hisi_trng_ctx *ctx = crypto_rng_ctx(tfm);
116 struct hisi_trng *trng = ctx->trng;
117 u32 data[SW_DRBG_DATA_NUM];
118 u32 currsize = 0;
119 u32 val = 0;
120 int ret;
121 u32 i;
122
123 if (dlen > SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES || dlen == 0) {
124 pr_err("dlen(%u) exceeds limit(%d)!\n", dlen,
125 SW_DRBG_BLOCKS_NUM * SW_DRBG_BYTES);
126 return -EINVAL;
127 }
128
129 do {
130 ret = readl_relaxed_poll_timeout(trng->base + SW_DRBG_STATUS,
131 val, val & BIT(1), SLEEP_US, TIMEOUT_US);
132 if (ret) {
133 pr_err("fail to generate random number(%d)!\n", ret);
134 break;
135 }
136
137 for (i = 0; i < SW_DRBG_DATA_NUM; i++)
138 data[i] = readl(trng->base + SW_DRBG_DATA(i));
139
140 if (dlen - currsize >= SW_DRBG_BYTES) {
141 memcpy(dstn + currsize, data, SW_DRBG_BYTES);
142 currsize += SW_DRBG_BYTES;
143 } else {
144 memcpy(dstn + currsize, data, dlen - currsize);
145 currsize = dlen;
146 }
147
148 writel(0x1, trng->base + SW_DRBG_GEN);
149 } while (currsize < dlen);
150
151 return ret;
152 }
153
hisi_trng_init(struct crypto_tfm * tfm)154 static int hisi_trng_init(struct crypto_tfm *tfm)
155 {
156 struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
157 struct hisi_trng *trng;
158 int ret = -EBUSY;
159
160 mutex_lock(&trng_devices.lock);
161 list_for_each_entry(trng, &trng_devices.list, list) {
162 if (!trng->is_used) {
163 trng->is_used = true;
164 ctx->trng = trng;
165 ret = 0;
166 break;
167 }
168 }
169 mutex_unlock(&trng_devices.lock);
170
171 return ret;
172 }
173
hisi_trng_exit(struct crypto_tfm * tfm)174 static void hisi_trng_exit(struct crypto_tfm *tfm)
175 {
176 struct hisi_trng_ctx *ctx = crypto_tfm_ctx(tfm);
177
178 mutex_lock(&trng_devices.lock);
179 ctx->trng->is_used = false;
180 mutex_unlock(&trng_devices.lock);
181 }
182
hisi_trng_read(struct hwrng * rng,void * buf,size_t max,bool wait)183 static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
184 {
185 struct hisi_trng *trng;
186 int currsize = 0;
187 u32 val = 0;
188 int ret;
189
190 trng = container_of(rng, struct hisi_trng, rng);
191
192 do {
193 ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
194 val, SLEEP_US, TIMEOUT_US);
195 if (ret)
196 return currsize;
197
198 if (max - currsize >= HISI_TRNG_BYTES) {
199 memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
200 currsize += HISI_TRNG_BYTES;
201 if (currsize == max)
202 return currsize;
203 continue;
204 }
205
206 /* copy remaining bytes */
207 memcpy(buf + currsize, &val, max - currsize);
208 currsize = max;
209 } while (currsize < max);
210
211 return currsize;
212 }
213
214 static struct rng_alg hisi_trng_alg = {
215 .generate = hisi_trng_generate,
216 .seed = hisi_trng_seed,
217 .seedsize = SW_DRBG_SEED_SIZE,
218 .base = {
219 .cra_name = "stdrng",
220 .cra_driver_name = "hisi_stdrng",
221 .cra_priority = 300,
222 .cra_ctxsize = sizeof(struct hisi_trng_ctx),
223 .cra_module = THIS_MODULE,
224 .cra_init = hisi_trng_init,
225 .cra_exit = hisi_trng_exit,
226 },
227 };
228
hisi_trng_add_to_list(struct hisi_trng * trng)229 static void hisi_trng_add_to_list(struct hisi_trng *trng)
230 {
231 mutex_lock(&trng_devices.lock);
232 list_add_tail(&trng->list, &trng_devices.list);
233 mutex_unlock(&trng_devices.lock);
234 }
235
hisi_trng_del_from_list(struct hisi_trng * trng)236 static int hisi_trng_del_from_list(struct hisi_trng *trng)
237 {
238 int ret = -EBUSY;
239
240 mutex_lock(&trng_devices.lock);
241 if (!trng->is_used) {
242 list_del(&trng->list);
243 ret = 0;
244 }
245 mutex_unlock(&trng_devices.lock);
246
247 return ret;
248 }
249
hisi_trng_probe(struct platform_device * pdev)250 static int hisi_trng_probe(struct platform_device *pdev)
251 {
252 struct hisi_trng *trng;
253 int ret;
254
255 trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
256 if (!trng)
257 return -ENOMEM;
258
259 platform_set_drvdata(pdev, trng);
260
261 trng->base = devm_platform_ioremap_resource(pdev, 0);
262 if (IS_ERR(trng->base))
263 return PTR_ERR(trng->base);
264
265 trng->is_used = false;
266 trng->ver = readl(trng->base + HISI_TRNG_VERSION);
267 if (!trng_devices.is_init) {
268 INIT_LIST_HEAD(&trng_devices.list);
269 mutex_init(&trng_devices.lock);
270 trng_devices.is_init = true;
271 }
272
273 hisi_trng_add_to_list(trng);
274 if (trng->ver != HISI_TRNG_VER_V1 &&
275 atomic_inc_return(&trng_active_devs) == 1) {
276 ret = crypto_register_rng(&hisi_trng_alg);
277 if (ret) {
278 dev_err(&pdev->dev,
279 "failed to register crypto(%d)\n", ret);
280 atomic_dec_return(&trng_active_devs);
281 goto err_remove_from_list;
282 }
283 }
284
285 trng->rng.name = pdev->name;
286 trng->rng.read = hisi_trng_read;
287 trng->rng.quality = HISI_TRNG_QUALITY;
288 ret = devm_hwrng_register(&pdev->dev, &trng->rng);
289 if (ret) {
290 dev_err(&pdev->dev, "failed to register hwrng: %d!\n", ret);
291 goto err_crypto_unregister;
292 }
293
294 return ret;
295
296 err_crypto_unregister:
297 if (trng->ver != HISI_TRNG_VER_V1 &&
298 atomic_dec_return(&trng_active_devs) == 0)
299 crypto_unregister_rng(&hisi_trng_alg);
300
301 err_remove_from_list:
302 hisi_trng_del_from_list(trng);
303 return ret;
304 }
305
hisi_trng_remove(struct platform_device * pdev)306 static void hisi_trng_remove(struct platform_device *pdev)
307 {
308 struct hisi_trng *trng = platform_get_drvdata(pdev);
309
310 /* Wait until the task is finished */
311 while (hisi_trng_del_from_list(trng))
312 ;
313
314 if (trng->ver != HISI_TRNG_VER_V1 &&
315 atomic_dec_return(&trng_active_devs) == 0)
316 crypto_unregister_rng(&hisi_trng_alg);
317 }
318
319 static const struct acpi_device_id hisi_trng_acpi_match[] = {
320 { "HISI02B3", 0 },
321 { }
322 };
323 MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);
324
325 static struct platform_driver hisi_trng_driver = {
326 .probe = hisi_trng_probe,
327 .remove_new = hisi_trng_remove,
328 .driver = {
329 .name = "hisi-trng-v2",
330 .acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
331 },
332 };
333
334 module_platform_driver(hisi_trng_driver);
335
336 MODULE_LICENSE("GPL v2");
337 MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
338 MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
339 MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");
340