drivers/crypto/stm32/stm32-crc32.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) STMicroelectronics SA 2017
   4  * Author: Fabien Dessenne <fabien.dessenne@st.com>
   5  */
   6
   7 #include <linux/bitrev.h>
   8 #include <linux/clk.h>
   9 #include <linux/crc32.h>
  10 #include <linux/crc32poly.h>
  11 #include <linux/io.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/mod_devicetable.h>
  15 #include <linux/platform_device.h>
  16 #include <linux/pm_runtime.h>
  17
  18 #include <crypto/internal/hash.h>
  19
  20 #include <asm/unaligned.h>
  21
  22 #define DRIVER_NAME             "stm32-crc32"
  23 #define CHKSUM_DIGEST_SIZE      4
  24 #define CHKSUM_BLOCK_SIZE       1
  25
  26 /* Registers */
  27 #define CRC_DR                  0x00000000
  28 #define CRC_CR                  0x00000008
  29 #define CRC_INIT                0x00000010
  30 #define CRC_POL                 0x00000014
  31
  32 /* Registers values */
  33 #define CRC_CR_RESET            BIT(0)
  34 #define CRC_CR_REV_IN_WORD      (BIT(6) | BIT(5))
  35 #define CRC_CR_REV_IN_BYTE      BIT(5)
  36 #define CRC_CR_REV_OUT          BIT(7)
  37 #define CRC32C_INIT_DEFAULT     0xFFFFFFFF
  38
  39 #define CRC_AUTOSUSPEND_DELAY   50
  40
  41 static unsigned int burst_size;
  42 module_param(burst_size, uint, 0644);
  43 MODULE_PARM_DESC(burst_size, "Select burst byte size (0 unlimited)");
  44
  45 struct stm32_crc {
  46         struct list_head list;
  47         struct device    *dev;
  48         void __iomem     *regs;
  49         struct clk       *clk;
  50         spinlock_t       lock;
  51 };
  52
  53 struct stm32_crc_list {
  54         struct list_head dev_list;
  55         spinlock_t       lock; /* protect dev_list */
  56 };
  57
  58 static struct stm32_crc_list crc_list = {
  59         .dev_list = LIST_HEAD_INIT(crc_list.dev_list),
  60         .lock     = __SPIN_LOCK_UNLOCKED(crc_list.lock),
  61 };
  62
  63 struct stm32_crc_ctx {
  64         u32 key;
  65         u32 poly;
  66 };
  67
  68 struct stm32_crc_desc_ctx {
  69         u32    partial; /* crc32c: partial in first 4 bytes of that struct */
  70 };
  71
  72 static int stm32_crc32_cra_init(struct crypto_tfm *tfm)
  73 {
  74         struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);
  75
  76         mctx->key = 0;
  77         mctx->poly = CRC32_POLY_LE;
  78         return 0;
  79 }
  80
  81 static int stm32_crc32c_cra_init(struct crypto_tfm *tfm)
  82 {
  83         struct stm32_crc_ctx *mctx = crypto_tfm_ctx(tfm);
  84
  85         mctx->key = CRC32C_INIT_DEFAULT;
  86         mctx->poly = CRC32C_POLY_LE;
  87         return 0;
  88 }
  89
  90 static int stm32_crc_setkey(struct crypto_shash *tfm, const u8 *key,
  91                             unsigned int keylen)
  92 {
  93         struct stm32_crc_ctx *mctx = crypto_shash_ctx(tfm);
  94
  95         if (keylen != sizeof(u32))
  96                 return -EINVAL;
  97
  98         mctx->key = get_unaligned_le32(key);
  99         return 0;
 100 }
 101
 102 static struct stm32_crc *stm32_crc_get_next_crc(void)
 103 {
 104         struct stm32_crc *crc;
 105
 106         spin_lock_bh(&crc_list.lock);
 107         crc = list_first_entry(&crc_list.dev_list, struct stm32_crc, list);
 108         if (crc)
 109                 list_move_tail(&crc->list, &crc_list.dev_list);
 110         spin_unlock_bh(&crc_list.lock);
 111
 112         return crc;
 113 }
 114
 115 static int stm32_crc_init(struct shash_desc *desc)
 116 {
 117         struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 118         struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 119         struct stm32_crc *crc;
 120         unsigned long flags;
 121
 122         crc = stm32_crc_get_next_crc();
 123         if (!crc)
 124                 return -ENODEV;
 125
 126         pm_runtime_get_sync(crc->dev);
 127
 128         spin_lock_irqsave(&crc->lock, flags);
 129
 130         /* Reset, set key, poly and configure in bit reverse mode */
 131         writel_relaxed(bitrev32(mctx->key), crc->regs + CRC_INIT);
 132         writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
 133         writel_relaxed(CRC_CR_RESET | CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 134                        crc->regs + CRC_CR);
 135
 136         /* Store partial result */
 137         ctx->partial = readl_relaxed(crc->regs + CRC_DR);
 138
 139         spin_unlock_irqrestore(&crc->lock, flags);
 140
 141         pm_runtime_mark_last_busy(crc->dev);
 142         pm_runtime_put_autosuspend(crc->dev);
 143
 144         return 0;
 145 }
 146
 147 static int burst_update(struct shash_desc *desc, const u8 *d8,
 148                         size_t length)
 149 {
 150         struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 151         struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 152         struct stm32_crc *crc;
 153
 154         crc = stm32_crc_get_next_crc();
 155         if (!crc)
 156                 return -ENODEV;
 157
 158         pm_runtime_get_sync(crc->dev);
 159
 160         if (!spin_trylock(&crc->lock)) {
 161                 /* Hardware is busy, calculate crc32 by software */
 162                 if (mctx->poly == CRC32_POLY_LE)
 163                         ctx->partial = crc32_le(ctx->partial, d8, length);
 164                 else
 165                         ctx->partial = __crc32c_le(ctx->partial, d8, length);
 166
 167                 goto pm_out;
 168         }
 169
 170         /*
 171          * Restore previously calculated CRC for this context as init value
 172          * Restore polynomial configuration
 173          * Configure in register for word input data,
 174          * Configure out register in reversed bit mode data.
 175          */
 176         writel_relaxed(bitrev32(ctx->partial), crc->regs + CRC_INIT);
 177         writel_relaxed(bitrev32(mctx->poly), crc->regs + CRC_POL);
 178         writel_relaxed(CRC_CR_RESET | CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 179                        crc->regs + CRC_CR);
 180
 181         if (d8 != PTR_ALIGN(d8, sizeof(u32))) {
 182                 /* Configure for byte data */
 183                 writel_relaxed(CRC_CR_REV_IN_BYTE | CRC_CR_REV_OUT,
 184                                crc->regs + CRC_CR);
 185                 while (d8 != PTR_ALIGN(d8, sizeof(u32)) && length) {
 186                         writeb_relaxed(*d8++, crc->regs + CRC_DR);
 187                         length--;
 188                 }
 189                 /* Configure for word data */
 190                 writel_relaxed(CRC_CR_REV_IN_WORD | CRC_CR_REV_OUT,
 191                                crc->regs + CRC_CR);
 192         }
 193
 194         for (; length >= sizeof(u32); d8 += sizeof(u32), length -= sizeof(u32))
 195                 writel_relaxed(*((u32 *)d8), crc->regs + CRC_DR);
 196
 197         if (length) {
 198                 /* Configure for byte data */
 199                 writel_relaxed(CRC_CR_REV_IN_BYTE | CRC_CR_REV_OUT,
 200                                crc->regs + CRC_CR);
 201                 while (length--)
 202                         writeb_relaxed(*d8++, crc->regs + CRC_DR);
 203         }
 204
 205         /* Store partial result */
 206         ctx->partial = readl_relaxed(crc->regs + CRC_DR);
 207
 208         spin_unlock(&crc->lock);
 209
 210 pm_out:
 211         pm_runtime_mark_last_busy(crc->dev);
 212         pm_runtime_put_autosuspend(crc->dev);
 213
 214         return 0;
 215 }
 216
 217 static int stm32_crc_update(struct shash_desc *desc, const u8 *d8,
 218                             unsigned int length)
 219 {
 220         const unsigned int burst_sz = burst_size;
 221         unsigned int rem_sz;
 222         const u8 *cur;
 223         size_t size;
 224         int ret;
 225
 226         if (!burst_sz)
 227                 return burst_update(desc, d8, length);
 228
 229         /* Digest first bytes not 32bit aligned at first pass in the loop */
 230         size = min_t(size_t, length, burst_sz + (size_t)d8 -
 231                                      ALIGN_DOWN((size_t)d8, sizeof(u32)));
 232         for (rem_sz = length, cur = d8; rem_sz;
 233              rem_sz -= size, cur += size, size = min(rem_sz, burst_sz)) {
 234                 ret = burst_update(desc, cur, size);
 235                 if (ret)
 236                         return ret;
 237         }
 238
 239         return 0;
 240 }
 241
 242 static int stm32_crc_final(struct shash_desc *desc, u8 *out)
 243 {
 244         struct stm32_crc_desc_ctx *ctx = shash_desc_ctx(desc);
 245         struct stm32_crc_ctx *mctx = crypto_shash_ctx(desc->tfm);
 246
 247         /* Send computed CRC */
 248         put_unaligned_le32(mctx->poly == CRC32C_POLY_LE ?
 249                            ~ctx->partial : ctx->partial, out);
 250
 251         return 0;
 252 }
 253
 254 static int stm32_crc_finup(struct shash_desc *desc, const u8 *data,
 255                            unsigned int length, u8 *out)
 256 {
 257         return stm32_crc_update(desc, data, length) ?:
 258                stm32_crc_final(desc, out);
 259 }
 260
 261 static int stm32_crc_digest(struct shash_desc *desc, const u8 *data,
 262                             unsigned int length, u8 *out)
 263 {
 264         return stm32_crc_init(desc) ?: stm32_crc_finup(desc, data, length, out);
 265 }
 266
 267 static unsigned int refcnt;
 268 static DEFINE_MUTEX(refcnt_lock);
 269 static struct shash_alg algs[] = {
 270         /* CRC-32 */
 271         {
 272                 .setkey         = stm32_crc_setkey,
 273                 .init           = stm32_crc_init,
 274                 .update         = stm32_crc_update,
 275                 .final          = stm32_crc_final,
 276                 .finup          = stm32_crc_finup,
 277                 .digest         = stm32_crc_digest,
 278                 .descsize       = sizeof(struct stm32_crc_desc_ctx),
 279                 .digestsize     = CHKSUM_DIGEST_SIZE,
 280                 .base           = {
 281                         .cra_name               = "crc32",
 282                         .cra_driver_name        = "stm32-crc32-crc32",
 283                         .cra_priority           = 200,
 284                         .cra_flags              = CRYPTO_ALG_OPTIONAL_KEY,
 285                         .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 286                         .cra_alignmask          = 3,
 287                         .cra_ctxsize            = sizeof(struct stm32_crc_ctx),
 288                         .cra_module             = THIS_MODULE,
 289                         .cra_init               = stm32_crc32_cra_init,
 290                 }
 291         },
 292         /* CRC-32Castagnoli */
 293         {
 294                 .setkey         = stm32_crc_setkey,
 295                 .init           = stm32_crc_init,
 296                 .update         = stm32_crc_update,
 297                 .final          = stm32_crc_final,
 298                 .finup          = stm32_crc_finup,
 299                 .digest         = stm32_crc_digest,
 300                 .descsize       = sizeof(struct stm32_crc_desc_ctx),
 301                 .digestsize     = CHKSUM_DIGEST_SIZE,
 302                 .base           = {
 303                         .cra_name               = "crc32c",
 304                         .cra_driver_name        = "stm32-crc32-crc32c",
 305                         .cra_priority           = 200,
 306                         .cra_flags              = CRYPTO_ALG_OPTIONAL_KEY,
 307                         .cra_blocksize          = CHKSUM_BLOCK_SIZE,
 308                         .cra_alignmask          = 3,
 309                         .cra_ctxsize            = sizeof(struct stm32_crc_ctx),
 310                         .cra_module             = THIS_MODULE,
 311                         .cra_init               = stm32_crc32c_cra_init,
 312                 }
 313         }
 314 };
 315
 316 static int stm32_crc_probe(struct platform_device *pdev)
 317 {
 318         struct device *dev = &pdev->dev;
 319         struct stm32_crc *crc;
 320         int ret;
 321
 322         crc = devm_kzalloc(dev, sizeof(*crc), GFP_KERNEL);
 323         if (!crc)
 324                 return -ENOMEM;
 325
 326         crc->dev = dev;
 327
 328         crc->regs = devm_platform_ioremap_resource(pdev, 0);
 329         if (IS_ERR(crc->regs)) {
 330                 dev_err(dev, "Cannot map CRC IO\n");
 331                 return PTR_ERR(crc->regs);
 332         }
 333
 334         crc->clk = devm_clk_get(dev, NULL);
 335         if (IS_ERR(crc->clk)) {
 336                 dev_err(dev, "Could not get clock\n");
 337                 return PTR_ERR(crc->clk);
 338         }
 339
 340         ret = clk_prepare_enable(crc->clk);
 341         if (ret) {
 342                 dev_err(crc->dev, "Failed to enable clock\n");
 343                 return ret;
 344         }
 345
 346         pm_runtime_set_autosuspend_delay(dev, CRC_AUTOSUSPEND_DELAY);
 347         pm_runtime_use_autosuspend(dev);
 348
 349         pm_runtime_get_noresume(dev);
 350         pm_runtime_set_active(dev);
 351         pm_runtime_irq_safe(dev);
 352         pm_runtime_enable(dev);
 353
 354         spin_lock_init(&crc->lock);
 355
 356         platform_set_drvdata(pdev, crc);
 357
 358         spin_lock(&crc_list.lock);
 359         list_add(&crc->list, &crc_list.dev_list);
 360         spin_unlock(&crc_list.lock);
 361
 362         mutex_lock(&refcnt_lock);
 363         if (!refcnt) {
 364                 ret = crypto_register_shashes(algs, ARRAY_SIZE(algs));
 365                 if (ret) {
 366                         mutex_unlock(&refcnt_lock);
 367                         dev_err(dev, "Failed to register\n");
 368                         clk_disable_unprepare(crc->clk);
 369                         return ret;
 370                 }
 371         }
 372         refcnt++;
 373         mutex_unlock(&refcnt_lock);
 374
 375         dev_info(dev, "Initialized\n");
 376
 377         pm_runtime_put_sync(dev);
 378
 379         return 0;
 380 }
 381
 382 static int stm32_crc_remove(struct platform_device *pdev)
 383 {
 384         struct stm32_crc *crc = platform_get_drvdata(pdev);
 385         int ret = pm_runtime_get_sync(crc->dev);
 386
 387         if (ret < 0)
 388                 return ret;
 389
 390         spin_lock(&crc_list.lock);
 391         list_del(&crc->list);
 392         spin_unlock(&crc_list.lock);
 393
 394         mutex_lock(&refcnt_lock);
 395         if (!--refcnt)
 396                 crypto_unregister_shashes(algs, ARRAY_SIZE(algs));
 397         mutex_unlock(&refcnt_lock);
 398
 399         pm_runtime_disable(crc->dev);
 400         pm_runtime_put_noidle(crc->dev);
 401
 402         clk_disable_unprepare(crc->clk);
 403
 404         return 0;
 405 }
 406
 407 static int __maybe_unused stm32_crc_suspend(struct device *dev)
 408 {
 409         struct stm32_crc *crc = dev_get_drvdata(dev);
 410         int ret;
 411
 412         ret = pm_runtime_force_suspend(dev);
 413         if (ret)
 414                 return ret;
 415
 416         clk_unprepare(crc->clk);
 417
 418         return 0;
 419 }
 420
 421 static int __maybe_unused stm32_crc_resume(struct device *dev)
 422 {
 423         struct stm32_crc *crc = dev_get_drvdata(dev);
 424         int ret;
 425
 426         ret = clk_prepare(crc->clk);
 427         if (ret) {
 428                 dev_err(crc->dev, "Failed to prepare clock\n");
 429                 return ret;
 430         }
 431
 432         return pm_runtime_force_resume(dev);
 433 }
 434
 435 static int __maybe_unused stm32_crc_runtime_suspend(struct device *dev)
 436 {
 437         struct stm32_crc *crc = dev_get_drvdata(dev);
 438
 439         clk_disable(crc->clk);
 440
 441         return 0;
 442 }
 443
 444 static int __maybe_unused stm32_crc_runtime_resume(struct device *dev)
 445 {
 446         struct stm32_crc *crc = dev_get_drvdata(dev);
 447         int ret;
 448
 449         ret = clk_enable(crc->clk);
 450         if (ret) {
 451                 dev_err(crc->dev, "Failed to enable clock\n");
 452                 return ret;
 453         }
 454
 455         return 0;
 456 }
 457
 458 static const struct dev_pm_ops stm32_crc_pm_ops = {
 459         SET_SYSTEM_SLEEP_PM_OPS(stm32_crc_suspend,
 460                                 stm32_crc_resume)
 461         SET_RUNTIME_PM_OPS(stm32_crc_runtime_suspend,
 462                            stm32_crc_runtime_resume, NULL)
 463 };
 464
 465 static const struct of_device_id stm32_dt_ids[] = {
 466         { .compatible = "st,stm32f7-crc", },
 467         {},
 468 };
 469 MODULE_DEVICE_TABLE(of, stm32_dt_ids);
 470
 471 static struct platform_driver stm32_crc_driver = {
 472         .probe  = stm32_crc_probe,
 473         .remove = stm32_crc_remove,
 474         .driver = {
 475                 .name           = DRIVER_NAME,
 476                 .pm             = &stm32_crc_pm_ops,
 477                 .of_match_table = stm32_dt_ids,
 478         },
 479 };
 480
 481 module_platform_driver(stm32_crc_driver);
 482
 483 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
 484 MODULE_DESCRIPTION("STMicrolectronics STM32 CRC32 hardware driver");
 485 MODULE_LICENSE("GPL");