drivers/mtd/nand/raw/omap_elm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Error Location Module
   4  *
   5  * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
   6  */
   7
   8 #define DRIVER_NAME     "omap-elm"
   9
  10 #include <linux/platform_device.h>
  11 #include <linux/module.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/of.h>
  15 #include <linux/sched.h>
  16 #include <linux/pm_runtime.h>
  17 #include <linux/platform_data/elm.h>
  18
  19 #define ELM_SYSCONFIG                   0x010
  20 #define ELM_IRQSTATUS                   0x018
  21 #define ELM_IRQENABLE                   0x01c
  22 #define ELM_LOCATION_CONFIG             0x020
  23 #define ELM_PAGE_CTRL                   0x080
  24 #define ELM_SYNDROME_FRAGMENT_0         0x400
  25 #define ELM_SYNDROME_FRAGMENT_1         0x404
  26 #define ELM_SYNDROME_FRAGMENT_2         0x408
  27 #define ELM_SYNDROME_FRAGMENT_3         0x40c
  28 #define ELM_SYNDROME_FRAGMENT_4         0x410
  29 #define ELM_SYNDROME_FRAGMENT_5         0x414
  30 #define ELM_SYNDROME_FRAGMENT_6         0x418
  31 #define ELM_LOCATION_STATUS             0x800
  32 #define ELM_ERROR_LOCATION_0            0x880
  33
  34 /* ELM Interrupt Status Register */
  35 #define INTR_STATUS_PAGE_VALID          BIT(8)
  36
  37 /* ELM Interrupt Enable Register */
  38 #define INTR_EN_PAGE_MASK               BIT(8)
  39
  40 /* ELM Location Configuration Register */
  41 #define ECC_BCH_LEVEL_MASK              0x3
  42
  43 /* ELM syndrome */
  44 #define ELM_SYNDROME_VALID              BIT(16)
  45
  46 /* ELM_LOCATION_STATUS Register */
  47 #define ECC_CORRECTABLE_MASK            BIT(8)
  48 #define ECC_NB_ERRORS_MASK              0x1f
  49
  50 /* ELM_ERROR_LOCATION_0-15 Registers */
  51 #define ECC_ERROR_LOCATION_MASK         0x1fff
  52
  53 #define ELM_ECC_SIZE                    0x7ff
  54
  55 #define SYNDROME_FRAGMENT_REG_SIZE      0x40
  56 #define ERROR_LOCATION_SIZE             0x100
  57
  58 struct elm_registers {
  59         u32 elm_irqenable;
  60         u32 elm_sysconfig;
  61         u32 elm_location_config;
  62         u32 elm_page_ctrl;
  63         u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
  64         u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
  65         u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
  66         u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
  67         u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
  68         u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
  69         u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
  70 };
  71
  72 struct elm_info {
  73         struct device *dev;
  74         void __iomem *elm_base;
  75         struct completion elm_completion;
  76         struct list_head list;
  77         enum bch_ecc bch_type;
  78         struct elm_registers elm_regs;
  79         int ecc_steps;
  80         int ecc_syndrome_size;
  81 };
  82
  83 static LIST_HEAD(elm_devices);
  84
  85 static void elm_write_reg(struct elm_info *info, int offset, u32 val)
  86 {
  87         writel(val, info->elm_base + offset);
  88 }
  89
  90 static u32 elm_read_reg(struct elm_info *info, int offset)
  91 {
  92         return readl(info->elm_base + offset);
  93 }
  94
  95 /**
  96  * elm_config - Configure ELM module
  97  * @dev:        ELM device
  98  * @bch_type:   Type of BCH ecc
  99  * @ecc_steps:  ECC steps to assign to config
 100  * @ecc_step_size:      ECC step size to assign to config
 101  * @ecc_syndrome_size:  ECC syndrome size to assign to config
 102  */
 103 int elm_config(struct device *dev, enum bch_ecc bch_type,
 104         int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
 105 {
 106         u32 reg_val;
 107         struct elm_info *info = dev_get_drvdata(dev);
 108
 109         if (!info) {
 110                 dev_err(dev, "Unable to configure elm - device not probed?\n");
 111                 return -EPROBE_DEFER;
 112         }
 113         /* ELM cannot detect ECC errors for chunks > 1KB */
 114         if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) {
 115                 dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size);
 116                 return -EINVAL;
 117         }
 118         /* ELM support 8 error syndrome process */
 119         if (ecc_steps > ERROR_VECTOR_MAX && ecc_steps % ERROR_VECTOR_MAX) {
 120                 dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps);
 121                 return -EINVAL;
 122         }
 123
 124         reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
 125         elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
 126         info->bch_type          = bch_type;
 127         info->ecc_steps         = ecc_steps;
 128         info->ecc_syndrome_size = ecc_syndrome_size;
 129
 130         return 0;
 131 }
 132 EXPORT_SYMBOL(elm_config);
 133
 134 /**
 135  * elm_configure_page_mode - Enable/Disable page mode
 136  * @info:       elm info
 137  * @index:      index number of syndrome fragment vector
 138  * @enable:     enable/disable flag for page mode
 139  *
 140  * Enable page mode for syndrome fragment index
 141  */
 142 static void elm_configure_page_mode(struct elm_info *info, int index,
 143                 bool enable)
 144 {
 145         u32 reg_val;
 146
 147         reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
 148         if (enable)
 149                 reg_val |= BIT(index);  /* enable page mode */
 150         else
 151                 reg_val &= ~BIT(index); /* disable page mode */
 152
 153         elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
 154 }
 155
 156 /**
 157  * elm_load_syndrome - Load ELM syndrome reg
 158  * @info:       elm info
 159  * @err_vec:    elm error vectors
 160  * @ecc:        buffer with calculated ecc
 161  *
 162  * Load syndrome fragment registers with calculated ecc in reverse order.
 163  */
 164 static void elm_load_syndrome(struct elm_info *info,
 165                 struct elm_errorvec *err_vec, u8 *ecc)
 166 {
 167         int i, offset;
 168         u32 val;
 169
 170         for (i = 0; i < info->ecc_steps; i++) {
 171
 172                 /* Check error reported */
 173                 if (err_vec[i].error_reported) {
 174                         elm_configure_page_mode(info, i, true);
 175                         offset = ELM_SYNDROME_FRAGMENT_0 +
 176                                 SYNDROME_FRAGMENT_REG_SIZE * i;
 177                         switch (info->bch_type) {
 178                         case BCH8_ECC:
 179                                 /* syndrome fragment 0 = ecc[9-12B] */
 180                                 val = cpu_to_be32(*(u32 *) &ecc[9]);
 181                                 elm_write_reg(info, offset, val);
 182
 183                                 /* syndrome fragment 1 = ecc[5-8B] */
 184                                 offset += 4;
 185                                 val = cpu_to_be32(*(u32 *) &ecc[5]);
 186                                 elm_write_reg(info, offset, val);
 187
 188                                 /* syndrome fragment 2 = ecc[1-4B] */
 189                                 offset += 4;
 190                                 val = cpu_to_be32(*(u32 *) &ecc[1]);
 191                                 elm_write_reg(info, offset, val);
 192
 193                                 /* syndrome fragment 3 = ecc[0B] */
 194                                 offset += 4;
 195                                 val = ecc[0];
 196                                 elm_write_reg(info, offset, val);
 197                                 break;
 198                         case BCH4_ECC:
 199                                 /* syndrome fragment 0 = ecc[20-52b] bits */
 200                                 val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
 201                                         ((ecc[2] & 0xf) << 28);
 202                                 elm_write_reg(info, offset, val);
 203
 204                                 /* syndrome fragment 1 = ecc[0-20b] bits */
 205                                 offset += 4;
 206                                 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
 207                                 elm_write_reg(info, offset, val);
 208                                 break;
 209                         case BCH16_ECC:
 210                                 val = cpu_to_be32(*(u32 *) &ecc[22]);
 211                                 elm_write_reg(info, offset, val);
 212                                 offset += 4;
 213                                 val = cpu_to_be32(*(u32 *) &ecc[18]);
 214                                 elm_write_reg(info, offset, val);
 215                                 offset += 4;
 216                                 val = cpu_to_be32(*(u32 *) &ecc[14]);
 217                                 elm_write_reg(info, offset, val);
 218                                 offset += 4;
 219                                 val = cpu_to_be32(*(u32 *) &ecc[10]);
 220                                 elm_write_reg(info, offset, val);
 221                                 offset += 4;
 222                                 val = cpu_to_be32(*(u32 *) &ecc[6]);
 223                                 elm_write_reg(info, offset, val);
 224                                 offset += 4;
 225                                 val = cpu_to_be32(*(u32 *) &ecc[2]);
 226                                 elm_write_reg(info, offset, val);
 227                                 offset += 4;
 228                                 val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16;
 229                                 elm_write_reg(info, offset, val);
 230                                 break;
 231                         default:
 232                                 pr_err("invalid config bch_type\n");
 233                         }
 234                 }
 235
 236                 /* Update ecc pointer with ecc byte size */
 237                 ecc += info->ecc_syndrome_size;
 238         }
 239 }
 240
 241 /**
 242  * elm_start_processing - start elm syndrome processing
 243  * @info:       elm info
 244  * @err_vec:    elm error vectors
 245  *
 246  * Set syndrome valid bit for syndrome fragment registers for which
 247  * elm syndrome fragment registers are loaded. This enables elm module
 248  * to start processing syndrome vectors.
 249  */
 250 static void elm_start_processing(struct elm_info *info,
 251                 struct elm_errorvec *err_vec)
 252 {
 253         int i, offset;
 254         u32 reg_val;
 255
 256         /*
 257          * Set syndrome vector valid, so that ELM module
 258          * will process it for vectors error is reported
 259          */
 260         for (i = 0; i < info->ecc_steps; i++) {
 261                 if (err_vec[i].error_reported) {
 262                         offset = ELM_SYNDROME_FRAGMENT_6 +
 263                                 SYNDROME_FRAGMENT_REG_SIZE * i;
 264                         reg_val = elm_read_reg(info, offset);
 265                         reg_val |= ELM_SYNDROME_VALID;
 266                         elm_write_reg(info, offset, reg_val);
 267                 }
 268         }
 269 }
 270
 271 /**
 272  * elm_error_correction - locate correctable error position
 273  * @info:       elm info
 274  * @err_vec:    elm error vectors
 275  *
 276  * On completion of processing by elm module, error location status
 277  * register updated with correctable/uncorrectable error information.
 278  * In case of correctable errors, number of errors located from
 279  * elm location status register & read the positions from
 280  * elm error location register.
 281  */
 282 static void elm_error_correction(struct elm_info *info,
 283                 struct elm_errorvec *err_vec)
 284 {
 285         int i, j;
 286         int offset;
 287         u32 reg_val;
 288
 289         for (i = 0; i < info->ecc_steps; i++) {
 290
 291                 /* Check error reported */
 292                 if (err_vec[i].error_reported) {
 293                         offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
 294                         reg_val = elm_read_reg(info, offset);
 295
 296                         /* Check correctable error or not */
 297                         if (reg_val & ECC_CORRECTABLE_MASK) {
 298                                 offset = ELM_ERROR_LOCATION_0 +
 299                                         ERROR_LOCATION_SIZE * i;
 300
 301                                 /* Read count of correctable errors */
 302                                 err_vec[i].error_count = reg_val &
 303                                         ECC_NB_ERRORS_MASK;
 304
 305                                 /* Update the error locations in error vector */
 306                                 for (j = 0; j < err_vec[i].error_count; j++) {
 307
 308                                         reg_val = elm_read_reg(info, offset);
 309                                         err_vec[i].error_loc[j] = reg_val &
 310                                                 ECC_ERROR_LOCATION_MASK;
 311
 312                                         /* Update error location register */
 313                                         offset += 4;
 314                                 }
 315                         } else {
 316                                 err_vec[i].error_uncorrectable = true;
 317                         }
 318
 319                         /* Clearing interrupts for processed error vectors */
 320                         elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
 321
 322                         /* Disable page mode */
 323                         elm_configure_page_mode(info, i, false);
 324                 }
 325         }
 326 }
 327
 328 /**
 329  * elm_decode_bch_error_page - Locate error position
 330  * @dev:        device pointer
 331  * @ecc_calc:   calculated ECC bytes from GPMC
 332  * @err_vec:    elm error vectors
 333  *
 334  * Called with one or more error reported vectors & vectors with
 335  * error reported is updated in err_vec[].error_reported
 336  */
 337 void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
 338                 struct elm_errorvec *err_vec)
 339 {
 340         struct elm_info *info = dev_get_drvdata(dev);
 341         u32 reg_val;
 342
 343         /* Enable page mode interrupt */
 344         reg_val = elm_read_reg(info, ELM_IRQSTATUS);
 345         elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
 346         elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
 347
 348         /* Load valid ecc byte to syndrome fragment register */
 349         elm_load_syndrome(info, err_vec, ecc_calc);
 350
 351         /* Enable syndrome processing for which syndrome fragment is updated */
 352         elm_start_processing(info, err_vec);
 353
 354         /* Wait for ELM module to finish locating error correction */
 355         wait_for_completion(&info->elm_completion);
 356
 357         /* Disable page mode interrupt */
 358         reg_val = elm_read_reg(info, ELM_IRQENABLE);
 359         elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
 360         elm_error_correction(info, err_vec);
 361 }
 362 EXPORT_SYMBOL(elm_decode_bch_error_page);
 363
 364 static irqreturn_t elm_isr(int this_irq, void *dev_id)
 365 {
 366         u32 reg_val;
 367         struct elm_info *info = dev_id;
 368
 369         reg_val = elm_read_reg(info, ELM_IRQSTATUS);
 370
 371         /* All error vectors processed */
 372         if (reg_val & INTR_STATUS_PAGE_VALID) {
 373                 elm_write_reg(info, ELM_IRQSTATUS,
 374                                 reg_val & INTR_STATUS_PAGE_VALID);
 375                 complete(&info->elm_completion);
 376                 return IRQ_HANDLED;
 377         }
 378
 379         return IRQ_NONE;
 380 }
 381
 382 static int elm_probe(struct platform_device *pdev)
 383 {
 384         int ret = 0;
 385         struct elm_info *info;
 386         int irq;
 387
 388         info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 389         if (!info)
 390                 return -ENOMEM;
 391
 392         info->dev = &pdev->dev;
 393
 394         irq = platform_get_irq(pdev, 0);
 395         if (irq < 0)
 396                 return irq;
 397
 398         info->elm_base = devm_platform_ioremap_resource(pdev, 0);
 399         if (IS_ERR(info->elm_base))
 400                 return PTR_ERR(info->elm_base);
 401
 402         ret = devm_request_irq(&pdev->dev, irq, elm_isr, 0,
 403                                pdev->name, info);
 404         if (ret) {
 405                 dev_err(&pdev->dev, "failure requesting %d\n", irq);
 406                 return ret;
 407         }
 408
 409         pm_runtime_enable(&pdev->dev);
 410         if (pm_runtime_get_sync(&pdev->dev) < 0) {
 411                 ret = -EINVAL;
 412                 pm_runtime_put_sync(&pdev->dev);
 413                 pm_runtime_disable(&pdev->dev);
 414                 dev_err(&pdev->dev, "can't enable clock\n");
 415                 return ret;
 416         }
 417
 418         init_completion(&info->elm_completion);
 419         INIT_LIST_HEAD(&info->list);
 420         list_add(&info->list, &elm_devices);
 421         platform_set_drvdata(pdev, info);
 422         return ret;
 423 }
 424
 425 static int elm_remove(struct platform_device *pdev)
 426 {
 427         pm_runtime_put_sync(&pdev->dev);
 428         pm_runtime_disable(&pdev->dev);
 429         return 0;
 430 }
 431
 432 #ifdef CONFIG_PM_SLEEP
 433 /*
 434  * elm_context_save
 435  * saves ELM configurations to preserve them across Hardware powered-down
 436  */
 437 static int elm_context_save(struct elm_info *info)
 438 {
 439         struct elm_registers *regs = &info->elm_regs;
 440         enum bch_ecc bch_type = info->bch_type;
 441         u32 offset = 0, i;
 442
 443         regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
 444         regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
 445         regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
 446         regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
 447         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
 448                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
 449                 switch (bch_type) {
 450                 case BCH16_ECC:
 451                         regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
 452                                         ELM_SYNDROME_FRAGMENT_6 + offset);
 453                         regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
 454                                         ELM_SYNDROME_FRAGMENT_5 + offset);
 455                         regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
 456                                         ELM_SYNDROME_FRAGMENT_4 + offset);
 457                         fallthrough;
 458                 case BCH8_ECC:
 459                         regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
 460                                         ELM_SYNDROME_FRAGMENT_3 + offset);
 461                         regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
 462                                         ELM_SYNDROME_FRAGMENT_2 + offset);
 463                         fallthrough;
 464                 case BCH4_ECC:
 465                         regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
 466                                         ELM_SYNDROME_FRAGMENT_1 + offset);
 467                         regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
 468                                         ELM_SYNDROME_FRAGMENT_0 + offset);
 469                         break;
 470                 default:
 471                         return -EINVAL;
 472                 }
 473                 /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
 474                  * to be saved for all BCH schemes*/
 475                 regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
 476                                         ELM_SYNDROME_FRAGMENT_6 + offset);
 477         }
 478         return 0;
 479 }
 480
 481 /*
 482  * elm_context_restore
 483  * writes configurations saved duing power-down back into ELM registers
 484  */
 485 static int elm_context_restore(struct elm_info *info)
 486 {
 487         struct elm_registers *regs = &info->elm_regs;
 488         enum bch_ecc bch_type = info->bch_type;
 489         u32 offset = 0, i;
 490
 491         elm_write_reg(info, ELM_IRQENABLE,       regs->elm_irqenable);
 492         elm_write_reg(info, ELM_SYSCONFIG,       regs->elm_sysconfig);
 493         elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
 494         elm_write_reg(info, ELM_PAGE_CTRL,       regs->elm_page_ctrl);
 495         for (i = 0; i < ERROR_VECTOR_MAX; i++) {
 496                 offset = i * SYNDROME_FRAGMENT_REG_SIZE;
 497                 switch (bch_type) {
 498                 case BCH16_ECC:
 499                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
 500                                         regs->elm_syndrome_fragment_6[i]);
 501                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
 502                                         regs->elm_syndrome_fragment_5[i]);
 503                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
 504                                         regs->elm_syndrome_fragment_4[i]);
 505                         fallthrough;
 506                 case BCH8_ECC:
 507                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
 508                                         regs->elm_syndrome_fragment_3[i]);
 509                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
 510                                         regs->elm_syndrome_fragment_2[i]);
 511                         fallthrough;
 512                 case BCH4_ECC:
 513                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
 514                                         regs->elm_syndrome_fragment_1[i]);
 515                         elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
 516                                         regs->elm_syndrome_fragment_0[i]);
 517                         break;
 518                 default:
 519                         return -EINVAL;
 520                 }
 521                 /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
 522                 elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
 523                                         regs->elm_syndrome_fragment_6[i] &
 524                                                          ELM_SYNDROME_VALID);
 525         }
 526         return 0;
 527 }
 528
 529 static int elm_suspend(struct device *dev)
 530 {
 531         struct elm_info *info = dev_get_drvdata(dev);
 532         elm_context_save(info);
 533         pm_runtime_put_sync(dev);
 534         return 0;
 535 }
 536
 537 static int elm_resume(struct device *dev)
 538 {
 539         struct elm_info *info = dev_get_drvdata(dev);
 540         pm_runtime_get_sync(dev);
 541         elm_context_restore(info);
 542         return 0;
 543 }
 544 #endif
 545
 546 static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
 547
 548 #ifdef CONFIG_OF
 549 static const struct of_device_id elm_of_match[] = {
 550         { .compatible = "ti,am3352-elm" },
 551         { .compatible = "ti,am64-elm" },
 552         {},
 553 };
 554 MODULE_DEVICE_TABLE(of, elm_of_match);
 555 #endif
 556
 557 static struct platform_driver elm_driver = {
 558         .driver = {
 559                 .name   = DRIVER_NAME,
 560                 .of_match_table = of_match_ptr(elm_of_match),
 561                 .pm     = &elm_pm_ops,
 562         },
 563         .probe  = elm_probe,
 564         .remove = elm_remove,
 565 };
 566
 567 module_platform_driver(elm_driver);
 568
 569 MODULE_DESCRIPTION("ELM driver for BCH error correction");
 570 MODULE_AUTHOR("Texas Instruments");
 571 MODULE_ALIAS("platform:" DRIVER_NAME);
 572 MODULE_LICENSE("GPL v2");