hisilicon/trng/trng.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (c) 2019 HiSilicon Limited. */
   3
   4 #include <linux/acpi.h>
   5 #include <linux/crypto.h>
   6 #include <linux/err.h>
   7 #include <linux/hw_random.h>
   8 #include <linux/io.h>
   9 #include <linux/iopoll.h>
  10 #include <linux/kernel.h>
  11 #include <linux/list.h>
  12 #include <linux/module.h>
  13 #include <linux/mutex.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/random.h>
  16 #include <crypto/internal/rng.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
  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
  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
 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(%d) 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
 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
 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
 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         u32 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
 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
 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
 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
 306 static int 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         return 0;
 319 }
 320
 321 static const struct acpi_device_id hisi_trng_acpi_match[] = {
 322         { "HISI02B3", 0 },
 323         { }
 324 };
 325 MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);
 326
 327 static struct platform_driver hisi_trng_driver = {
 328         .probe          = hisi_trng_probe,
 329         .remove         = hisi_trng_remove,
 330         .driver         = {
 331                 .name   = "hisi-trng-v2",
 332                 .acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
 333         },
 334 };
 335
 336 module_platform_driver(hisi_trng_driver);
 337
 338 MODULE_LICENSE("GPL v2");
 339 MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
 340 MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
 341 MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");