LXR linux/drivers/mtd/nand/omap

   1/*
   2 * Error Location Module
   3 *
   4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 *
  16 */
  17
  18#define DRIVER_NAME     "omap-elm"
  19
  20#include <linux/platform_device.h>
  21#include <linux/module.h>
  22#include <linux/interrupt.h>
  23#include <linux/io.h>
  24#include <linux/of.h>
  25#include <linux/sched.h>
  26#include <linux/pm_runtime.h>
  27#include <linux/platform_data/elm.h>
  28
  29#define ELM_SYSCONFIG                   0x010
  30#define ELM_IRQSTATUS                   0x018
  31#define ELM_IRQENABLE                   0x01c
  32#define ELM_LOCATION_CONFIG             0x020
  33#define ELM_PAGE_CTRL                   0x080
  34#define ELM_SYNDROME_FRAGMENT_0         0x400
  35#define ELM_SYNDROME_FRAGMENT_1         0x404
  36#define ELM_SYNDROME_FRAGMENT_2         0x408
  37#define ELM_SYNDROME_FRAGMENT_3         0x40c
  38#define ELM_SYNDROME_FRAGMENT_4         0x410
  39#define ELM_SYNDROME_FRAGMENT_5         0x414
  40#define ELM_SYNDROME_FRAGMENT_6         0x418
  41#define ELM_LOCATION_STATUS             0x800
  42#define ELM_ERROR_LOCATION_0            0x880
  43
  44/* ELM Interrupt Status Register */
  45#define INTR_STATUS_PAGE_VALID          BIT(8)
  46
  47/* ELM Interrupt Enable Register */
  48#define INTR_EN_PAGE_MASK               BIT(8)
  49
  50/* ELM Location Configuration Register */
  51#define ECC_BCH_LEVEL_MASK              0x3
  52
  53/* ELM syndrome */
  54#define ELM_SYNDROME_VALID              BIT(16)
  55
  56/* ELM_LOCATION_STATUS Register */
  57#define ECC_CORRECTABLE_MASK            BIT(8)
  58#define ECC_NB_ERRORS_MASK              0x1f
  59
  60/* ELM_ERROR_LOCATION_0-15 Registers */
  61#define ECC_ERROR_LOCATION_MASK         0x1fff
  62
  63#define ELM_ECC_SIZE                    0x7ff
  64
  65#define SYNDROME_FRAGMENT_REG_SIZE      0x40
  66#define ERROR_LOCATION_SIZE             0x100
  67
  68struct elm_registers {
  69        u32 elm_irqenable;
  70        u32 elm_sysconfig;
  71        u32 elm_location_config;
  72        u32 elm_page_ctrl;
  73        u32 elm_syndrome_fragment_6[ERROR_VECTOR_MAX];
  74        u32 elm_syndrome_fragment_5[ERROR_VECTOR_MAX];
  75        u32 elm_syndrome_fragment_4[ERROR_VECTOR_MAX];
  76        u32 elm_syndrome_fragment_3[ERROR_VECTOR_MAX];
  77        u32 elm_syndrome_fragment_2[ERROR_VECTOR_MAX];
  78        u32 elm_syndrome_fragment_1[ERROR_VECTOR_MAX];
  79        u32 elm_syndrome_fragment_0[ERROR_VECTOR_MAX];
  80};
  81
  82struct elm_info {
  83        struct device *dev;
  84        void __iomem *elm_base;
  85        struct completion elm_completion;
  86        struct list_head list;
  87        enum bch_ecc bch_type;
  88        struct elm_registers elm_regs;
  89        int ecc_steps;
  90        int ecc_syndrome_size;
  91};
  92
  93static LIST_HEAD(elm_devices);
  94
  95static void elm_write_reg(struct elm_info *info, int offset, u32 val)
  96{
  97        writel(val, info->elm_base + offset);
  98}
  99
 100static u32 elm_read_reg(struct elm_info *info, int offset)
 101{
 102        return readl(info->elm_base + offset);
 103}
 104
 105/**
 106 * elm_config - Configure ELM module
 107 * @dev:        ELM device
 108 * @bch_type:   Type of BCH ecc
 109 */
 110int elm_config(struct device *dev, enum bch_ecc bch_type,
 111        int ecc_steps, int ecc_step_size, int ecc_syndrome_size)
 112{
 113        u32 reg_val;
 114        struct elm_info *info = dev_get_drvdata(dev);
 115
 116        if (!info) {
 117                dev_err(dev, "Unable to configure elm - device not probed?\n");
 118                return -EPROBE_DEFER;
 119        }
 120        /* ELM cannot detect ECC errors for chunks > 1KB */
 121        if (ecc_step_size > ((ELM_ECC_SIZE + 1) / 2)) {
 122                dev_err(dev, "unsupported config ecc-size=%d\n", ecc_step_size);
 123                return -EINVAL;
 124        }
 125        /* ELM support 8 error syndrome process */
 126        if (ecc_steps > ERROR_VECTOR_MAX) {
 127                dev_err(dev, "unsupported config ecc-step=%d\n", ecc_steps);
 128                return -EINVAL;
 129        }
 130
 131        reg_val = (bch_type & ECC_BCH_LEVEL_MASK) | (ELM_ECC_SIZE << 16);
 132        elm_write_reg(info, ELM_LOCATION_CONFIG, reg_val);
 133        info->bch_type          = bch_type;
 134        info->ecc_steps         = ecc_steps;
 135        info->ecc_syndrome_size = ecc_syndrome_size;
 136
 137        return 0;
 138}
 139EXPORT_SYMBOL(elm_config);
 140
 141/**
 142 * elm_configure_page_mode - Enable/Disable page mode
 143 * @info:       elm info
 144 * @index:      index number of syndrome fragment vector
 145 * @enable:     enable/disable flag for page mode
 146 *
 147 * Enable page mode for syndrome fragment index
 148 */
 149static void elm_configure_page_mode(struct elm_info *info, int index,
 150                bool enable)
 151{
 152        u32 reg_val;
 153
 154        reg_val = elm_read_reg(info, ELM_PAGE_CTRL);
 155        if (enable)
 156                reg_val |= BIT(index);  /* enable page mode */
 157        else
 158                reg_val &= ~BIT(index); /* disable page mode */
 159
 160        elm_write_reg(info, ELM_PAGE_CTRL, reg_val);
 161}
 162
 163/**
 164 * elm_load_syndrome - Load ELM syndrome reg
 165 * @info:       elm info
 166 * @err_vec:    elm error vectors
 167 * @ecc:        buffer with calculated ecc
 168 *
 169 * Load syndrome fragment registers with calculated ecc in reverse order.
 170 */
 171static void elm_load_syndrome(struct elm_info *info,
 172                struct elm_errorvec *err_vec, u8 *ecc)
 173{
 174        int i, offset;
 175        u32 val;
 176
 177        for (i = 0; i < info->ecc_steps; i++) {
 178
 179                /* Check error reported */
 180                if (err_vec[i].error_reported) {
 181                        elm_configure_page_mode(info, i, true);
 182                        offset = ELM_SYNDROME_FRAGMENT_0 +
 183                                SYNDROME_FRAGMENT_REG_SIZE * i;
 184                        switch (info->bch_type) {
 185                        case BCH8_ECC:
 186                                /* syndrome fragment 0 = ecc[9-12B] */
 187                                val = cpu_to_be32(*(u32 *) &ecc[9]);
 188                                elm_write_reg(info, offset, val);
 189
 190                                /* syndrome fragment 1 = ecc[5-8B] */
 191                                offset += 4;
 192                                val = cpu_to_be32(*(u32 *) &ecc[5]);
 193                                elm_write_reg(info, offset, val);
 194
 195                                /* syndrome fragment 2 = ecc[1-4B] */
 196                                offset += 4;
 197                                val = cpu_to_be32(*(u32 *) &ecc[1]);
 198                                elm_write_reg(info, offset, val);
 199
 200                                /* syndrome fragment 3 = ecc[0B] */
 201                                offset += 4;
 202                                val = ecc[0];
 203                                elm_write_reg(info, offset, val);
 204                                break;
 205                        case BCH4_ECC:
 206                                /* syndrome fragment 0 = ecc[20-52b] bits */
 207                                val = (cpu_to_be32(*(u32 *) &ecc[3]) >> 4) |
 208                                        ((ecc[2] & 0xf) << 28);
 209                                elm_write_reg(info, offset, val);
 210
 211                                /* syndrome fragment 1 = ecc[0-20b] bits */
 212                                offset += 4;
 213                                val = cpu_to_be32(*(u32 *) &ecc[0]) >> 12;
 214                                elm_write_reg(info, offset, val);
 215                                break;
 216                        case BCH16_ECC:
 217                                val = cpu_to_be32(*(u32 *) &ecc[22]);
 218                                elm_write_reg(info, offset, val);
 219                                offset += 4;
 220                                val = cpu_to_be32(*(u32 *) &ecc[18]);
 221                                elm_write_reg(info, offset, val);
 222                                offset += 4;
 223                                val = cpu_to_be32(*(u32 *) &ecc[14]);
 224                                elm_write_reg(info, offset, val);
 225                                offset += 4;
 226                                val = cpu_to_be32(*(u32 *) &ecc[10]);
 227                                elm_write_reg(info, offset, val);
 228                                offset += 4;
 229                                val = cpu_to_be32(*(u32 *) &ecc[6]);
 230                                elm_write_reg(info, offset, val);
 231                                offset += 4;
 232                                val = cpu_to_be32(*(u32 *) &ecc[2]);
 233                                elm_write_reg(info, offset, val);
 234                                offset += 4;
 235                                val = cpu_to_be32(*(u32 *) &ecc[0]) >> 16;
 236                                elm_write_reg(info, offset, val);
 237                                break;
 238                        default:
 239                                pr_err("invalid config bch_type\n");
 240                        }
 241                }
 242
 243                /* Update ecc pointer with ecc byte size */
 244                ecc += info->ecc_syndrome_size;
 245        }
 246}
 247
 248/**
 249 * elm_start_processing - start elm syndrome processing
 250 * @info:       elm info
 251 * @err_vec:    elm error vectors
 252 *
 253 * Set syndrome valid bit for syndrome fragment registers for which
 254 * elm syndrome fragment registers are loaded. This enables elm module
 255 * to start processing syndrome vectors.
 256 */
 257static void elm_start_processing(struct elm_info *info,
 258                struct elm_errorvec *err_vec)
 259{
 260        int i, offset;
 261        u32 reg_val;
 262
 263        /*
 264         * Set syndrome vector valid, so that ELM module
 265         * will process it for vectors error is reported
 266         */
 267        for (i = 0; i < info->ecc_steps; i++) {
 268                if (err_vec[i].error_reported) {
 269                        offset = ELM_SYNDROME_FRAGMENT_6 +
 270                                SYNDROME_FRAGMENT_REG_SIZE * i;
 271                        reg_val = elm_read_reg(info, offset);
 272                        reg_val |= ELM_SYNDROME_VALID;
 273                        elm_write_reg(info, offset, reg_val);
 274                }
 275        }
 276}
 277
 278/**
 279 * elm_error_correction - locate correctable error position
 280 * @info:       elm info
 281 * @err_vec:    elm error vectors
 282 *
 283 * On completion of processing by elm module, error location status
 284 * register updated with correctable/uncorrectable error information.
 285 * In case of correctable errors, number of errors located from
 286 * elm location status register & read the positions from
 287 * elm error location register.
 288 */
 289static void elm_error_correction(struct elm_info *info,
 290                struct elm_errorvec *err_vec)
 291{
 292        int i, j, errors = 0;
 293        int offset;
 294        u32 reg_val;
 295
 296        for (i = 0; i < info->ecc_steps; i++) {
 297
 298                /* Check error reported */
 299                if (err_vec[i].error_reported) {
 300                        offset = ELM_LOCATION_STATUS + ERROR_LOCATION_SIZE * i;
 301                        reg_val = elm_read_reg(info, offset);
 302
 303                        /* Check correctable error or not */
 304                        if (reg_val & ECC_CORRECTABLE_MASK) {
 305                                offset = ELM_ERROR_LOCATION_0 +
 306                                        ERROR_LOCATION_SIZE * i;
 307
 308                                /* Read count of correctable errors */
 309                                err_vec[i].error_count = reg_val &
 310                                        ECC_NB_ERRORS_MASK;
 311
 312                                /* Update the error locations in error vector */
 313                                for (j = 0; j < err_vec[i].error_count; j++) {
 314
 315                                        reg_val = elm_read_reg(info, offset);
 316                                        err_vec[i].error_loc[j] = reg_val &
 317                                                ECC_ERROR_LOCATION_MASK;
 318
 319                                        /* Update error location register */
 320                                        offset += 4;
 321                                }
 322
 323                                errors += err_vec[i].error_count;
 324                        } else {
 325                                err_vec[i].error_uncorrectable = true;
 326                        }
 327
 328                        /* Clearing interrupts for processed error vectors */
 329                        elm_write_reg(info, ELM_IRQSTATUS, BIT(i));
 330
 331                        /* Disable page mode */
 332                        elm_configure_page_mode(info, i, false);
 333                }
 334        }
 335}
 336
 337/**
 338 * elm_decode_bch_error_page - Locate error position
 339 * @dev:        device pointer
 340 * @ecc_calc:   calculated ECC bytes from GPMC
 341 * @err_vec:    elm error vectors
 342 *
 343 * Called with one or more error reported vectors & vectors with
 344 * error reported is updated in err_vec[].error_reported
 345 */
 346void elm_decode_bch_error_page(struct device *dev, u8 *ecc_calc,
 347                struct elm_errorvec *err_vec)
 348{
 349        struct elm_info *info = dev_get_drvdata(dev);
 350        u32 reg_val;
 351
 352        /* Enable page mode interrupt */
 353        reg_val = elm_read_reg(info, ELM_IRQSTATUS);
 354        elm_write_reg(info, ELM_IRQSTATUS, reg_val & INTR_STATUS_PAGE_VALID);
 355        elm_write_reg(info, ELM_IRQENABLE, INTR_EN_PAGE_MASK);
 356
 357        /* Load valid ecc byte to syndrome fragment register */
 358        elm_load_syndrome(info, err_vec, ecc_calc);
 359
 360        /* Enable syndrome processing for which syndrome fragment is updated */
 361        elm_start_processing(info, err_vec);
 362
 363        /* Wait for ELM module to finish locating error correction */
 364        wait_for_completion(&info->elm_completion);
 365
 366        /* Disable page mode interrupt */
 367        reg_val = elm_read_reg(info, ELM_IRQENABLE);
 368        elm_write_reg(info, ELM_IRQENABLE, reg_val & ~INTR_EN_PAGE_MASK);
 369        elm_error_correction(info, err_vec);
 370}
 371EXPORT_SYMBOL(elm_decode_bch_error_page);
 372
 373static irqreturn_t elm_isr(int this_irq, void *dev_id)
 374{
 375        u32 reg_val;
 376        struct elm_info *info = dev_id;
 377
 378        reg_val = elm_read_reg(info, ELM_IRQSTATUS);
 379
 380        /* All error vectors processed */
 381        if (reg_val & INTR_STATUS_PAGE_VALID) {
 382                elm_write_reg(info, ELM_IRQSTATUS,
 383                                reg_val & INTR_STATUS_PAGE_VALID);
 384                complete(&info->elm_completion);
 385                return IRQ_HANDLED;
 386        }
 387
 388        return IRQ_NONE;
 389}
 390
 391static int elm_probe(struct platform_device *pdev)
 392{
 393        int ret = 0;
 394        struct resource *res, *irq;
 395        struct elm_info *info;
 396
 397        info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 398        if (!info)
 399                return -ENOMEM;
 400
 401        info->dev = &pdev->dev;
 402
 403        irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 404        if (!irq) {
 405                dev_err(&pdev->dev, "no irq resource defined\n");
 406                return -ENODEV;
 407        }
 408
 409        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 410        info->elm_base = devm_ioremap_resource(&pdev->dev, res);
 411        if (IS_ERR(info->elm_base))
 412                return PTR_ERR(info->elm_base);
 413
 414        ret = devm_request_irq(&pdev->dev, irq->start, elm_isr, 0,
 415                        pdev->name, info);
 416        if (ret) {
 417                dev_err(&pdev->dev, "failure requesting %pr\n", irq);
 418                return ret;
 419        }
 420
 421        pm_runtime_enable(&pdev->dev);
 422        if (pm_runtime_get_sync(&pdev->dev) < 0) {
 423                ret = -EINVAL;
 424                pm_runtime_disable(&pdev->dev);
 425                dev_err(&pdev->dev, "can't enable clock\n");
 426                return ret;
 427        }
 428
 429        init_completion(&info->elm_completion);
 430        INIT_LIST_HEAD(&info->list);
 431        list_add(&info->list, &elm_devices);
 432        platform_set_drvdata(pdev, info);
 433        return ret;
 434}
 435
 436static int elm_remove(struct platform_device *pdev)
 437{
 438        pm_runtime_put_sync(&pdev->dev);
 439        pm_runtime_disable(&pdev->dev);
 440        return 0;
 441}
 442
 443#ifdef CONFIG_PM_SLEEP
 444/**
 445 * elm_context_save
 446 * saves ELM configurations to preserve them across Hardware powered-down
 447 */
 448static int elm_context_save(struct elm_info *info)
 449{
 450        struct elm_registers *regs = &info->elm_regs;
 451        enum bch_ecc bch_type = info->bch_type;
 452        u32 offset = 0, i;
 453
 454        regs->elm_irqenable       = elm_read_reg(info, ELM_IRQENABLE);
 455        regs->elm_sysconfig       = elm_read_reg(info, ELM_SYSCONFIG);
 456        regs->elm_location_config = elm_read_reg(info, ELM_LOCATION_CONFIG);
 457        regs->elm_page_ctrl       = elm_read_reg(info, ELM_PAGE_CTRL);
 458        for (i = 0; i < ERROR_VECTOR_MAX; i++) {
 459                offset = i * SYNDROME_FRAGMENT_REG_SIZE;
 460                switch (bch_type) {
 461                case BCH16_ECC:
 462                        regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
 463                                        ELM_SYNDROME_FRAGMENT_6 + offset);
 464                        regs->elm_syndrome_fragment_5[i] = elm_read_reg(info,
 465                                        ELM_SYNDROME_FRAGMENT_5 + offset);
 466                        regs->elm_syndrome_fragment_4[i] = elm_read_reg(info,
 467                                        ELM_SYNDROME_FRAGMENT_4 + offset);
 468                case BCH8_ECC:
 469                        regs->elm_syndrome_fragment_3[i] = elm_read_reg(info,
 470                                        ELM_SYNDROME_FRAGMENT_3 + offset);
 471                        regs->elm_syndrome_fragment_2[i] = elm_read_reg(info,
 472                                        ELM_SYNDROME_FRAGMENT_2 + offset);
 473                case BCH4_ECC:
 474                        regs->elm_syndrome_fragment_1[i] = elm_read_reg(info,
 475                                        ELM_SYNDROME_FRAGMENT_1 + offset);
 476                        regs->elm_syndrome_fragment_0[i] = elm_read_reg(info,
 477                                        ELM_SYNDROME_FRAGMENT_0 + offset);
 478                        break;
 479                default:
 480                        return -EINVAL;
 481                }
 482                /* ELM SYNDROME_VALID bit in SYNDROME_FRAGMENT_6[] needs
 483                 * to be saved for all BCH schemes*/
 484                regs->elm_syndrome_fragment_6[i] = elm_read_reg(info,
 485                                        ELM_SYNDROME_FRAGMENT_6 + offset);
 486        }
 487        return 0;
 488}
 489
 490/**
 491 * elm_context_restore
 492 * writes configurations saved duing power-down back into ELM registers
 493 */
 494static int elm_context_restore(struct elm_info *info)
 495{
 496        struct elm_registers *regs = &info->elm_regs;
 497        enum bch_ecc bch_type = info->bch_type;
 498        u32 offset = 0, i;
 499
 500        elm_write_reg(info, ELM_IRQENABLE,       regs->elm_irqenable);
 501        elm_write_reg(info, ELM_SYSCONFIG,       regs->elm_sysconfig);
 502        elm_write_reg(info, ELM_LOCATION_CONFIG, regs->elm_location_config);
 503        elm_write_reg(info, ELM_PAGE_CTRL,       regs->elm_page_ctrl);
 504        for (i = 0; i < ERROR_VECTOR_MAX; i++) {
 505                offset = i * SYNDROME_FRAGMENT_REG_SIZE;
 506                switch (bch_type) {
 507                case BCH16_ECC:
 508                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
 509                                        regs->elm_syndrome_fragment_6[i]);
 510                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_5 + offset,
 511                                        regs->elm_syndrome_fragment_5[i]);
 512                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_4 + offset,
 513                                        regs->elm_syndrome_fragment_4[i]);
 514                case BCH8_ECC:
 515                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_3 + offset,
 516                                        regs->elm_syndrome_fragment_3[i]);
 517                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_2 + offset,
 518                                        regs->elm_syndrome_fragment_2[i]);
 519                case BCH4_ECC:
 520                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_1 + offset,
 521                                        regs->elm_syndrome_fragment_1[i]);
 522                        elm_write_reg(info, ELM_SYNDROME_FRAGMENT_0 + offset,
 523                                        regs->elm_syndrome_fragment_0[i]);
 524                        break;
 525                default:
 526                        return -EINVAL;
 527                }
 528                /* ELM_SYNDROME_VALID bit to be set in last to trigger FSM */
 529                elm_write_reg(info, ELM_SYNDROME_FRAGMENT_6 + offset,
 530                                        regs->elm_syndrome_fragment_6[i] &
 531                                                         ELM_SYNDROME_VALID);
 532        }
 533        return 0;
 534}
 535
 536static int elm_suspend(struct device *dev)
 537{
 538        struct elm_info *info = dev_get_drvdata(dev);
 539        elm_context_save(info);
 540        pm_runtime_put_sync(dev);
 541        return 0;
 542}
 543
 544static int elm_resume(struct device *dev)
 545{
 546        struct elm_info *info = dev_get_drvdata(dev);
 547        pm_runtime_get_sync(dev);
 548        elm_context_restore(info);
 549        return 0;
 550}
 551#endif
 552
 553static SIMPLE_DEV_PM_OPS(elm_pm_ops, elm_suspend, elm_resume);
 554
 555#ifdef CONFIG_OF
 556static const struct of_device_id elm_of_match[] = {
 557        { .compatible = "ti,am3352-elm" },
 558        {},
 559};
 560MODULE_DEVICE_TABLE(of, elm_of_match);
 561#endif
 562
 563static struct platform_driver elm_driver = {
 564        .driver = {
 565                .name   = DRIVER_NAME,
 566                .of_match_table = of_match_ptr(elm_of_match),
 567                .pm     = &elm_pm_ops,
 568        },
 569        .probe  = elm_probe,
 570        .remove = elm_remove,
 571};
 572
 573module_platform_driver(elm_driver);
 574
 575MODULE_DESCRIPTION("ELM driver for BCH error correction");
 576MODULE_AUTHOR("Texas Instruments");
 577MODULE_ALIAS("platform:" DRIVER_NAME);
 578MODULE_LICENSE("GPL v2");
 579