linux/drivers/mtd/sm_ftl.c
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   1/*
   2 * Copyright © 2009 - Maxim Levitsky
   3 * SmartMedia/xD translation layer
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 */
   9
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12#include <linux/random.h>
  13#include <linux/hdreg.h>
  14#include <linux/kthread.h>
  15#include <linux/freezer.h>
  16#include <linux/sysfs.h>
  17#include <linux/bitops.h>
  18#include <linux/slab.h>
  19#include <linux/mtd/nand_ecc.h>
  20#include "nand/sm_common.h"
  21#include "sm_ftl.h"
  22
  23
  24
  25struct workqueue_struct *cache_flush_workqueue;
  26
  27static int cache_timeout = 1000;
  28module_param(cache_timeout, int, S_IRUGO);
  29MODULE_PARM_DESC(cache_timeout,
  30        "Timeout (in ms) for cache flush (1000 ms default");
  31
  32static int debug;
  33module_param(debug, int, S_IRUGO | S_IWUSR);
  34MODULE_PARM_DESC(debug, "Debug level (0-2)");
  35
  36
  37/* ------------------- sysfs attributes ---------------------------------- */
  38struct sm_sysfs_attribute {
  39        struct device_attribute dev_attr;
  40        char *data;
  41        int len;
  42};
  43
  44ssize_t sm_attr_show(struct device *dev, struct device_attribute *attr,
  45                     char *buf)
  46{
  47        struct sm_sysfs_attribute *sm_attr =
  48                container_of(attr, struct sm_sysfs_attribute, dev_attr);
  49
  50        strncpy(buf, sm_attr->data, sm_attr->len);
  51        return sm_attr->len;
  52}
  53
  54
  55#define NUM_ATTRIBUTES 1
  56#define SM_CIS_VENDOR_OFFSET 0x59
  57struct attribute_group *sm_create_sysfs_attributes(struct sm_ftl *ftl)
  58{
  59        struct attribute_group *attr_group;
  60        struct attribute **attributes;
  61        struct sm_sysfs_attribute *vendor_attribute;
  62
  63        int vendor_len = strnlen(ftl->cis_buffer + SM_CIS_VENDOR_OFFSET,
  64                                        SM_SMALL_PAGE - SM_CIS_VENDOR_OFFSET);
  65
  66        char *vendor = kmalloc(vendor_len, GFP_KERNEL);
  67        if (!vendor)
  68                goto error1;
  69        memcpy(vendor, ftl->cis_buffer + SM_CIS_VENDOR_OFFSET, vendor_len);
  70        vendor[vendor_len] = 0;
  71
  72        /* Initialize sysfs attributes */
  73        vendor_attribute =
  74                kzalloc(sizeof(struct sm_sysfs_attribute), GFP_KERNEL);
  75        if (!vendor_attribute)
  76                goto error2;
  77
  78        sysfs_attr_init(&vendor_attribute->dev_attr.attr);
  79
  80        vendor_attribute->data = vendor;
  81        vendor_attribute->len = vendor_len;
  82        vendor_attribute->dev_attr.attr.name = "vendor";
  83        vendor_attribute->dev_attr.attr.mode = S_IRUGO;
  84        vendor_attribute->dev_attr.show = sm_attr_show;
  85
  86
  87        /* Create array of pointers to the attributes */
  88        attributes = kzalloc(sizeof(struct attribute *) * (NUM_ATTRIBUTES + 1),
  89                                                                GFP_KERNEL);
  90        if (!attributes)
  91                goto error3;
  92        attributes[0] = &vendor_attribute->dev_attr.attr;
  93
  94        /* Finally create the attribute group */
  95        attr_group = kzalloc(sizeof(struct attribute_group), GFP_KERNEL);
  96        if (!attr_group)
  97                goto error4;
  98        attr_group->attrs = attributes;
  99        return attr_group;
 100error4:
 101        kfree(attributes);
 102error3:
 103        kfree(vendor_attribute);
 104error2:
 105        kfree(vendor);
 106error1:
 107        return NULL;
 108}
 109
 110void sm_delete_sysfs_attributes(struct sm_ftl *ftl)
 111{
 112        struct attribute **attributes = ftl->disk_attributes->attrs;
 113        int i;
 114
 115        for (i = 0; attributes[i] ; i++) {
 116
 117                struct device_attribute *dev_attr = container_of(attributes[i],
 118                        struct device_attribute, attr);
 119
 120                struct sm_sysfs_attribute *sm_attr =
 121                        container_of(dev_attr,
 122                                struct sm_sysfs_attribute, dev_attr);
 123
 124                kfree(sm_attr->data);
 125                kfree(sm_attr);
 126        }
 127
 128        kfree(ftl->disk_attributes->attrs);
 129        kfree(ftl->disk_attributes);
 130}
 131
 132
 133/* ----------------------- oob helpers -------------------------------------- */
 134
 135static int sm_get_lba(uint8_t *lba)
 136{
 137        /* check fixed bits */
 138        if ((lba[0] & 0xF8) != 0x10)
 139                return -2;
 140
 141        /* check parity - endianness doesn't matter */
 142        if (hweight16(*(uint16_t *)lba) & 1)
 143                return -2;
 144
 145        return (lba[1] >> 1) | ((lba[0] & 0x07) << 7);
 146}
 147
 148
 149/*
 150 * Read LBA associated with block
 151 * returns -1, if block is erased
 152 * returns -2 if error happens
 153 */
 154static int sm_read_lba(struct sm_oob *oob)
 155{
 156        static const uint32_t erased_pattern[4] = {
 157                0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF };
 158
 159        uint16_t lba_test;
 160        int lba;
 161
 162        /* First test for erased block */
 163        if (!memcmp(oob, erased_pattern, SM_OOB_SIZE))
 164                return -1;
 165
 166        /* Now check is both copies of the LBA differ too much */
 167        lba_test = *(uint16_t *)oob->lba_copy1 ^ *(uint16_t*)oob->lba_copy2;
 168        if (lba_test && !is_power_of_2(lba_test))
 169                return -2;
 170
 171        /* And read it */
 172        lba = sm_get_lba(oob->lba_copy1);
 173
 174        if (lba == -2)
 175                lba = sm_get_lba(oob->lba_copy2);
 176
 177        return lba;
 178}
 179
 180static void sm_write_lba(struct sm_oob *oob, uint16_t lba)
 181{
 182        uint8_t tmp[2];
 183
 184        WARN_ON(lba >= 1000);
 185
 186        tmp[0] = 0x10 | ((lba >> 7) & 0x07);
 187        tmp[1] = (lba << 1) & 0xFF;
 188
 189        if (hweight16(*(uint16_t *)tmp) & 0x01)
 190                tmp[1] |= 1;
 191
 192        oob->lba_copy1[0] = oob->lba_copy2[0] = tmp[0];
 193        oob->lba_copy1[1] = oob->lba_copy2[1] = tmp[1];
 194}
 195
 196
 197/* Make offset from parts */
 198static loff_t sm_mkoffset(struct sm_ftl *ftl, int zone, int block, int boffset)
 199{
 200        WARN_ON(boffset & (SM_SECTOR_SIZE - 1));
 201        WARN_ON(zone < 0 || zone >= ftl->zone_count);
 202        WARN_ON(block >= ftl->zone_size);
 203        WARN_ON(boffset >= ftl->block_size);
 204
 205        if (block == -1)
 206                return -1;
 207
 208        return (zone * SM_MAX_ZONE_SIZE + block) * ftl->block_size + boffset;
 209}
 210
 211/* Breaks offset into parts */
 212static void sm_break_offset(struct sm_ftl *ftl, loff_t offset,
 213                            int *zone, int *block, int *boffset)
 214{
 215        *boffset = do_div(offset, ftl->block_size);
 216        *block = do_div(offset, ftl->max_lba);
 217        *zone = offset >= ftl->zone_count ? -1 : offset;
 218}
 219
 220/* ---------------------- low level IO ------------------------------------- */
 221
 222static int sm_correct_sector(uint8_t *buffer, struct sm_oob *oob)
 223{
 224        uint8_t ecc[3];
 225
 226        __nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
 227        if (__nand_correct_data(buffer, ecc, oob->ecc1, SM_SMALL_PAGE) < 0)
 228                return -EIO;
 229
 230        buffer += SM_SMALL_PAGE;
 231
 232        __nand_calculate_ecc(buffer, SM_SMALL_PAGE, ecc);
 233        if (__nand_correct_data(buffer, ecc, oob->ecc2, SM_SMALL_PAGE) < 0)
 234                return -EIO;
 235        return 0;
 236}
 237
 238/* Reads a sector + oob*/
 239static int sm_read_sector(struct sm_ftl *ftl,
 240                          int zone, int block, int boffset,
 241                          uint8_t *buffer, struct sm_oob *oob)
 242{
 243        struct mtd_info *mtd = ftl->trans->mtd;
 244        struct mtd_oob_ops ops;
 245        struct sm_oob tmp_oob;
 246        int ret = -EIO;
 247        int try = 0;
 248
 249        /* FTL can contain -1 entries that are by default filled with bits */
 250        if (block == -1) {
 251                memset(buffer, 0xFF, SM_SECTOR_SIZE);
 252                return 0;
 253        }
 254
 255        /* User might not need the oob, but we do for data verification */
 256        if (!oob)
 257                oob = &tmp_oob;
 258
 259        ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
 260        ops.ooboffs = 0;
 261        ops.ooblen = SM_OOB_SIZE;
 262        ops.oobbuf = (void *)oob;
 263        ops.len = SM_SECTOR_SIZE;
 264        ops.datbuf = buffer;
 265
 266again:
 267        if (try++) {
 268                /* Avoid infinite recursion on CIS reads, sm_recheck_media
 269                        won't help anyway */
 270                if (zone == 0 && block == ftl->cis_block && boffset ==
 271                        ftl->cis_boffset)
 272                        return ret;
 273
 274                /* Test if media is stable */
 275                if (try == 3 || sm_recheck_media(ftl))
 276                        return ret;
 277        }
 278
 279        /* Unfortunately, oob read will _always_ succeed,
 280                despite card removal..... */
 281        ret = mtd_read_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 282
 283        /* Test for unknown errors */
 284        if (ret != 0 && !mtd_is_bitflip_or_eccerr(ret)) {
 285                dbg("read of block %d at zone %d, failed due to error (%d)",
 286                        block, zone, ret);
 287                goto again;
 288        }
 289
 290        /* Do a basic test on the oob, to guard against returned garbage */
 291        if (oob->reserved != 0xFFFFFFFF && !is_power_of_2(~oob->reserved))
 292                goto again;
 293
 294        /* This should never happen, unless there is a bug in the mtd driver */
 295        WARN_ON(ops.oobretlen != SM_OOB_SIZE);
 296        WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
 297
 298        if (!buffer)
 299                return 0;
 300
 301        /* Test if sector marked as bad */
 302        if (!sm_sector_valid(oob)) {
 303                dbg("read of block %d at zone %d, failed because it is marked"
 304                        " as bad" , block, zone);
 305                goto again;
 306        }
 307
 308        /* Test ECC*/
 309        if (mtd_is_eccerr(ret) ||
 310                (ftl->smallpagenand && sm_correct_sector(buffer, oob))) {
 311
 312                dbg("read of block %d at zone %d, failed due to ECC error",
 313                        block, zone);
 314                goto again;
 315        }
 316
 317        return 0;
 318}
 319
 320/* Writes a sector to media */
 321static int sm_write_sector(struct sm_ftl *ftl,
 322                           int zone, int block, int boffset,
 323                           uint8_t *buffer, struct sm_oob *oob)
 324{
 325        struct mtd_oob_ops ops;
 326        struct mtd_info *mtd = ftl->trans->mtd;
 327        int ret;
 328
 329        BUG_ON(ftl->readonly);
 330
 331        if (zone == 0 && (block == ftl->cis_block || block == 0)) {
 332                dbg("attempted to write the CIS!");
 333                return -EIO;
 334        }
 335
 336        if (ftl->unstable)
 337                return -EIO;
 338
 339        ops.mode = ftl->smallpagenand ? MTD_OPS_RAW : MTD_OPS_PLACE_OOB;
 340        ops.len = SM_SECTOR_SIZE;
 341        ops.datbuf = buffer;
 342        ops.ooboffs = 0;
 343        ops.ooblen = SM_OOB_SIZE;
 344        ops.oobbuf = (void *)oob;
 345
 346        ret = mtd_write_oob(mtd, sm_mkoffset(ftl, zone, block, boffset), &ops);
 347
 348        /* Now we assume that hardware will catch write bitflip errors */
 349
 350        if (ret) {
 351                dbg("write to block %d at zone %d, failed with error %d",
 352                        block, zone, ret);
 353
 354                sm_recheck_media(ftl);
 355                return ret;
 356        }
 357
 358        /* This should never happen, unless there is a bug in the driver */
 359        WARN_ON(ops.oobretlen != SM_OOB_SIZE);
 360        WARN_ON(buffer && ops.retlen != SM_SECTOR_SIZE);
 361
 362        return 0;
 363}
 364
 365/* ------------------------ block IO ------------------------------------- */
 366
 367/* Write a block using data and lba, and invalid sector bitmap */
 368static int sm_write_block(struct sm_ftl *ftl, uint8_t *buf,
 369                          int zone, int block, int lba,
 370                          unsigned long invalid_bitmap)
 371{
 372        struct sm_oob oob;
 373        int boffset;
 374        int retry = 0;
 375
 376        /* Initialize the oob with requested values */
 377        memset(&oob, 0xFF, SM_OOB_SIZE);
 378        sm_write_lba(&oob, lba);
 379restart:
 380        if (ftl->unstable)
 381                return -EIO;
 382
 383        for (boffset = 0; boffset < ftl->block_size;
 384                                boffset += SM_SECTOR_SIZE) {
 385
 386                oob.data_status = 0xFF;
 387
 388                if (test_bit(boffset / SM_SECTOR_SIZE, &invalid_bitmap)) {
 389
 390                        sm_printk("sector %d of block at LBA %d of zone %d"
 391                                " coudn't be read, marking it as invalid",
 392                                boffset / SM_SECTOR_SIZE, lba, zone);
 393
 394                        oob.data_status = 0;
 395                }
 396
 397                if (ftl->smallpagenand) {
 398                        __nand_calculate_ecc(buf + boffset,
 399                                                SM_SMALL_PAGE, oob.ecc1);
 400
 401                        __nand_calculate_ecc(buf + boffset + SM_SMALL_PAGE,
 402                                                SM_SMALL_PAGE, oob.ecc2);
 403                }
 404                if (!sm_write_sector(ftl, zone, block, boffset,
 405                                                        buf + boffset, &oob))
 406                        continue;
 407
 408                if (!retry) {
 409
 410                        /* If write fails. try to erase the block */
 411                        /* This is safe, because we never write in blocks
 412                                that contain valuable data.
 413                        This is intended to repair block that are marked
 414                        as erased, but that isn't fully erased*/
 415
 416                        if (sm_erase_block(ftl, zone, block, 0))
 417                                return -EIO;
 418
 419                        retry = 1;
 420                        goto restart;
 421                } else {
 422                        sm_mark_block_bad(ftl, zone, block);
 423                        return -EIO;
 424                }
 425        }
 426        return 0;
 427}
 428
 429
 430/* Mark whole block at offset 'offs' as bad. */
 431static void sm_mark_block_bad(struct sm_ftl *ftl, int zone, int block)
 432{
 433        struct sm_oob oob;
 434        int boffset;
 435
 436        memset(&oob, 0xFF, SM_OOB_SIZE);
 437        oob.block_status = 0xF0;
 438
 439        if (ftl->unstable)
 440                return;
 441
 442        if (sm_recheck_media(ftl))
 443                return;
 444
 445        sm_printk("marking block %d of zone %d as bad", block, zone);
 446
 447        /* We aren't checking the return value, because we don't care */
 448        /* This also fails on fake xD cards, but I guess these won't expose
 449                any bad blocks till fail completely */
 450        for (boffset = 0; boffset < ftl->block_size; boffset += SM_SECTOR_SIZE)
 451                sm_write_sector(ftl, zone, block, boffset, NULL, &oob);
 452}
 453
 454/*
 455 * Erase a block within a zone
 456 * If erase succeeds, it updates free block fifo, otherwise marks block as bad
 457 */
 458static int sm_erase_block(struct sm_ftl *ftl, int zone_num, uint16_t block,
 459                          int put_free)
 460{
 461        struct ftl_zone *zone = &ftl->zones[zone_num];
 462        struct mtd_info *mtd = ftl->trans->mtd;
 463        struct erase_info erase;
 464
 465        erase.mtd = mtd;
 466        erase.callback = sm_erase_callback;
 467        erase.addr = sm_mkoffset(ftl, zone_num, block, 0);
 468        erase.len = ftl->block_size;
 469        erase.priv = (u_long)ftl;
 470
 471        if (ftl->unstable)
 472                return -EIO;
 473
 474        BUG_ON(ftl->readonly);
 475
 476        if (zone_num == 0 && (block == ftl->cis_block || block == 0)) {
 477                sm_printk("attempted to erase the CIS!");
 478                return -EIO;
 479        }
 480
 481        if (mtd_erase(mtd, &erase)) {
 482                sm_printk("erase of block %d in zone %d failed",
 483                                                        block, zone_num);
 484                goto error;
 485        }
 486
 487        if (erase.state == MTD_ERASE_PENDING)
 488                wait_for_completion(&ftl->erase_completion);
 489
 490        if (erase.state != MTD_ERASE_DONE) {
 491                sm_printk("erase of block %d in zone %d failed after wait",
 492                        block, zone_num);
 493                goto error;
 494        }
 495
 496        if (put_free)
 497                kfifo_in(&zone->free_sectors,
 498                        (const unsigned char *)&block, sizeof(block));
 499
 500        return 0;
 501error:
 502        sm_mark_block_bad(ftl, zone_num, block);
 503        return -EIO;
 504}
 505
 506static void sm_erase_callback(struct erase_info *self)
 507{
 508        struct sm_ftl *ftl = (struct sm_ftl *)self->priv;
 509        complete(&ftl->erase_completion);
 510}
 511
 512/* Thoroughly test that block is valid. */
 513static int sm_check_block(struct sm_ftl *ftl, int zone, int block)
 514{
 515        int boffset;
 516        struct sm_oob oob;
 517        int lbas[] = { -3, 0, 0, 0 };
 518        int i = 0;
 519        int test_lba;
 520
 521
 522        /* First just check that block doesn't look fishy */
 523        /* Only blocks that are valid or are sliced in two parts, are
 524                accepted */
 525        for (boffset = 0; boffset < ftl->block_size;
 526                                        boffset += SM_SECTOR_SIZE) {
 527
 528                /* This shouldn't happen anyway */
 529                if (sm_read_sector(ftl, zone, block, boffset, NULL, &oob))
 530                        return -2;
 531
 532                test_lba = sm_read_lba(&oob);
 533
 534                if (lbas[i] != test_lba)
 535                        lbas[++i] = test_lba;
 536
 537                /* If we found three different LBAs, something is fishy */
 538                if (i == 3)
 539                        return -EIO;
 540        }
 541
 542        /* If the block is sliced (partially erased usually) erase it */
 543        if (i == 2) {
 544                sm_erase_block(ftl, zone, block, 1);
 545                return 1;
 546        }
 547
 548        return 0;
 549}
 550
 551/* ----------------- media scanning --------------------------------- */
 552static const struct chs_entry chs_table[] = {
 553        { 1,    125,  4,  4  },
 554        { 2,    125,  4,  8  },
 555        { 4,    250,  4,  8  },
 556        { 8,    250,  4,  16 },
 557        { 16,   500,  4,  16 },
 558        { 32,   500,  8,  16 },
 559        { 64,   500,  8,  32 },
 560        { 128,  500,  16, 32 },
 561        { 256,  1000, 16, 32 },
 562        { 512,  1015, 32, 63 },
 563        { 1024, 985,  33, 63 },
 564        { 2048, 985,  33, 63 },
 565        { 0 },
 566};
 567
 568
 569static const uint8_t cis_signature[] = {
 570        0x01, 0x03, 0xD9, 0x01, 0xFF, 0x18, 0x02, 0xDF, 0x01, 0x20
 571};
 572/* Find out media parameters.
 573 * This ideally has to be based on nand id, but for now device size is enough */
 574int sm_get_media_info(struct sm_ftl *ftl, struct mtd_info *mtd)
 575{
 576        int i;
 577        int size_in_megs = mtd->size / (1024 * 1024);
 578
 579        ftl->readonly = mtd->type == MTD_ROM;
 580
 581        /* Manual settings for very old devices */
 582        ftl->zone_count = 1;
 583        ftl->smallpagenand = 0;
 584
 585        switch (size_in_megs) {
 586        case 1:
 587                /* 1 MiB flash/rom SmartMedia card (256 byte pages)*/
 588                ftl->zone_size = 256;
 589                ftl->max_lba = 250;
 590                ftl->block_size = 8 * SM_SECTOR_SIZE;
 591                ftl->smallpagenand = 1;
 592
 593                break;
 594        case 2:
 595                /* 2 MiB flash SmartMedia (256 byte pages)*/
 596                if (mtd->writesize == SM_SMALL_PAGE) {
 597                        ftl->zone_size = 512;
 598                        ftl->max_lba = 500;
 599                        ftl->block_size = 8 * SM_SECTOR_SIZE;
 600                        ftl->smallpagenand = 1;
 601                /* 2 MiB rom SmartMedia */
 602                } else {
 603
 604                        if (!ftl->readonly)
 605                                return -ENODEV;
 606
 607                        ftl->zone_size = 256;
 608                        ftl->max_lba = 250;
 609                        ftl->block_size = 16 * SM_SECTOR_SIZE;
 610                }
 611                break;
 612        case 4:
 613                /* 4 MiB flash/rom SmartMedia device */
 614                ftl->zone_size = 512;
 615                ftl->max_lba = 500;
 616                ftl->block_size = 16 * SM_SECTOR_SIZE;
 617                break;
 618        case 8:
 619                /* 8 MiB flash/rom SmartMedia device */
 620                ftl->zone_size = 1024;
 621                ftl->max_lba = 1000;
 622                ftl->block_size = 16 * SM_SECTOR_SIZE;
 623        }
 624
 625        /* Minimum xD size is 16MiB. Also, all xD cards have standard zone
 626           sizes. SmartMedia cards exist up to 128 MiB and have same layout*/
 627        if (size_in_megs >= 16) {
 628                ftl->zone_count = size_in_megs / 16;
 629                ftl->zone_size = 1024;
 630                ftl->max_lba = 1000;
 631                ftl->block_size = 32 * SM_SECTOR_SIZE;
 632        }
 633
 634        /* Test for proper write,erase and oob sizes */
 635        if (mtd->erasesize > ftl->block_size)
 636                return -ENODEV;
 637
 638        if (mtd->writesize > SM_SECTOR_SIZE)
 639                return -ENODEV;
 640
 641        if (ftl->smallpagenand && mtd->oobsize < SM_SMALL_OOB_SIZE)
 642                return -ENODEV;
 643
 644        if (!ftl->smallpagenand && mtd->oobsize < SM_OOB_SIZE)
 645                return -ENODEV;
 646
 647        /* We use OOB */
 648        if (!mtd_has_oob(mtd))
 649                return -ENODEV;
 650
 651        /* Find geometry information */
 652        for (i = 0 ; i < ARRAY_SIZE(chs_table) ; i++) {
 653                if (chs_table[i].size == size_in_megs) {
 654                        ftl->cylinders = chs_table[i].cyl;
 655                        ftl->heads = chs_table[i].head;
 656                        ftl->sectors = chs_table[i].sec;
 657                        return 0;
 658                }
 659        }
 660
 661        sm_printk("media has unknown size : %dMiB", size_in_megs);
 662        ftl->cylinders = 985;
 663        ftl->heads =  33;
 664        ftl->sectors = 63;
 665        return 0;
 666}
 667
 668/* Validate the CIS */
 669static int sm_read_cis(struct sm_ftl *ftl)
 670{
 671        struct sm_oob oob;
 672
 673        if (sm_read_sector(ftl,
 674                0, ftl->cis_block, ftl->cis_boffset, ftl->cis_buffer, &oob))
 675                        return -EIO;
 676
 677        if (!sm_sector_valid(&oob) || !sm_block_valid(&oob))
 678                return -EIO;
 679
 680        if (!memcmp(ftl->cis_buffer + ftl->cis_page_offset,
 681                        cis_signature, sizeof(cis_signature))) {
 682                return 0;
 683        }
 684
 685        return -EIO;
 686}
 687
 688/* Scan the media for the CIS */
 689static int sm_find_cis(struct sm_ftl *ftl)
 690{
 691        struct sm_oob oob;
 692        int block, boffset;
 693        int block_found = 0;
 694        int cis_found = 0;
 695
 696        /* Search for first valid block */
 697        for (block = 0 ; block < ftl->zone_size - ftl->max_lba ; block++) {
 698
 699                if (sm_read_sector(ftl, 0, block, 0, NULL, &oob))
 700                        continue;
 701
 702                if (!sm_block_valid(&oob))
 703                        continue;
 704                block_found = 1;
 705                break;
 706        }
 707
 708        if (!block_found)
 709                return -EIO;
 710
 711        /* Search for first valid sector in this block */
 712        for (boffset = 0 ; boffset < ftl->block_size;
 713                                                boffset += SM_SECTOR_SIZE) {
 714
 715                if (sm_read_sector(ftl, 0, block, boffset, NULL, &oob))
 716                        continue;
 717
 718                if (!sm_sector_valid(&oob))
 719                        continue;
 720                break;
 721        }
 722
 723        if (boffset == ftl->block_size)
 724                return -EIO;
 725
 726        ftl->cis_block = block;
 727        ftl->cis_boffset = boffset;
 728        ftl->cis_page_offset = 0;
 729
 730        cis_found = !sm_read_cis(ftl);
 731
 732        if (!cis_found) {
 733                ftl->cis_page_offset = SM_SMALL_PAGE;
 734                cis_found = !sm_read_cis(ftl);
 735        }
 736
 737        if (cis_found) {
 738                dbg("CIS block found at offset %x",
 739                        block * ftl->block_size +
 740                                boffset + ftl->cis_page_offset);
 741                return 0;
 742        }
 743        return -EIO;
 744}
 745
 746/* Basic test to determine if underlying mtd device if functional */
 747static int sm_recheck_media(struct sm_ftl *ftl)
 748{
 749        if (sm_read_cis(ftl)) {
 750
 751                if (!ftl->unstable) {
 752                        sm_printk("media unstable, not allowing writes");
 753                        ftl->unstable = 1;
 754                }
 755                return -EIO;
 756        }
 757        return 0;
 758}
 759
 760/* Initialize a FTL zone */
 761static int sm_init_zone(struct sm_ftl *ftl, int zone_num)
 762{
 763        struct ftl_zone *zone = &ftl->zones[zone_num];
 764        struct sm_oob oob;
 765        uint16_t block;
 766        int lba;
 767        int i = 0;
 768        int len;
 769
 770        dbg("initializing zone %d", zone_num);
 771
 772        /* Allocate memory for FTL table */
 773        zone->lba_to_phys_table = kmalloc(ftl->max_lba * 2, GFP_KERNEL);
 774
 775        if (!zone->lba_to_phys_table)
 776                return -ENOMEM;
 777        memset(zone->lba_to_phys_table, -1, ftl->max_lba * 2);
 778
 779
 780        /* Allocate memory for free sectors FIFO */
 781        if (kfifo_alloc(&zone->free_sectors, ftl->zone_size * 2, GFP_KERNEL)) {
 782                kfree(zone->lba_to_phys_table);
 783                return -ENOMEM;
 784        }
 785
 786        /* Now scan the zone */
 787        for (block = 0 ; block < ftl->zone_size ; block++) {
 788
 789                /* Skip blocks till the CIS (including) */
 790                if (zone_num == 0 && block <= ftl->cis_block)
 791                        continue;
 792
 793                /* Read the oob of first sector */
 794                if (sm_read_sector(ftl, zone_num, block, 0, NULL, &oob))
 795                        return -EIO;
 796
 797                /* Test to see if block is erased. It is enough to test
 798                        first sector, because erase happens in one shot */
 799                if (sm_block_erased(&oob)) {
 800                        kfifo_in(&zone->free_sectors,
 801                                (unsigned char *)&block, 2);
 802                        continue;
 803                }
 804
 805                /* If block is marked as bad, skip it */
 806                /* This assumes we can trust first sector*/
 807                /* However the way the block valid status is defined, ensures
 808                        very low probability of failure here */
 809                if (!sm_block_valid(&oob)) {
 810                        dbg("PH %04d <-> <marked bad>", block);
 811                        continue;
 812                }
 813
 814
 815                lba = sm_read_lba(&oob);
 816
 817                /* Invalid LBA means that block is damaged. */
 818                /* We can try to erase it, or mark it as bad, but
 819                        lets leave that to recovery application */
 820                if (lba == -2 || lba >= ftl->max_lba) {
 821                        dbg("PH %04d <-> LBA %04d(bad)", block, lba);
 822                        continue;
 823                }
 824
 825
 826                /* If there is no collision,
 827                        just put the sector in the FTL table */
 828                if (zone->lba_to_phys_table[lba] < 0) {
 829                        dbg_verbose("PH %04d <-> LBA %04d", block, lba);
 830                        zone->lba_to_phys_table[lba] = block;
 831                        continue;
 832                }
 833
 834                sm_printk("collision"
 835                        " of LBA %d between blocks %d and %d in zone %d",
 836                        lba, zone->lba_to_phys_table[lba], block, zone_num);
 837
 838                /* Test that this block is valid*/
 839                if (sm_check_block(ftl, zone_num, block))
 840                        continue;
 841
 842                /* Test now the old block */
 843                if (sm_check_block(ftl, zone_num,
 844                                        zone->lba_to_phys_table[lba])) {
 845                        zone->lba_to_phys_table[lba] = block;
 846                        continue;
 847                }
 848
 849                /* If both blocks are valid and share same LBA, it means that
 850                        they hold different versions of same data. It not
 851                        known which is more recent, thus just erase one of them
 852                */
 853                sm_printk("both blocks are valid, erasing the later");
 854                sm_erase_block(ftl, zone_num, block, 1);
 855        }
 856
 857        dbg("zone initialized");
 858        zone->initialized = 1;
 859
 860        /* No free sectors, means that the zone is heavily damaged, write won't
 861                work, but it can still can be (partially) read */
 862        if (!kfifo_len(&zone->free_sectors)) {
 863                sm_printk("no free blocks in zone %d", zone_num);
 864                return 0;
 865        }
 866
 867        /* Randomize first block we write to */
 868        get_random_bytes(&i, 2);
 869        i %= (kfifo_len(&zone->free_sectors) / 2);
 870
 871        while (i--) {
 872                len = kfifo_out(&zone->free_sectors,
 873                                        (unsigned char *)&block, 2);
 874                WARN_ON(len != 2);
 875                kfifo_in(&zone->free_sectors, (const unsigned char *)&block, 2);
 876        }
 877        return 0;
 878}
 879
 880/* Get and automatically initialize an FTL mapping for one zone */
 881struct ftl_zone *sm_get_zone(struct sm_ftl *ftl, int zone_num)
 882{
 883        struct ftl_zone *zone;
 884        int error;
 885
 886        BUG_ON(zone_num >= ftl->zone_count);
 887        zone = &ftl->zones[zone_num];
 888
 889        if (!zone->initialized) {
 890                error = sm_init_zone(ftl, zone_num);
 891
 892                if (error)
 893                        return ERR_PTR(error);
 894        }
 895        return zone;
 896}
 897
 898
 899/* ----------------- cache handling ------------------------------------------*/
 900
 901/* Initialize the one block cache */
 902void sm_cache_init(struct sm_ftl *ftl)
 903{
 904        ftl->cache_data_invalid_bitmap = 0xFFFFFFFF;
 905        ftl->cache_clean = 1;
 906        ftl->cache_zone = -1;
 907        ftl->cache_block = -1;
 908        /*memset(ftl->cache_data, 0xAA, ftl->block_size);*/
 909}
 910
 911/* Put sector in one block cache */
 912void sm_cache_put(struct sm_ftl *ftl, char *buffer, int boffset)
 913{
 914        memcpy(ftl->cache_data + boffset, buffer, SM_SECTOR_SIZE);
 915        clear_bit(boffset / SM_SECTOR_SIZE, &ftl->cache_data_invalid_bitmap);
 916        ftl->cache_clean = 0;
 917}
 918
 919/* Read a sector from the cache */
 920int sm_cache_get(struct sm_ftl *ftl, char *buffer, int boffset)
 921{
 922        if (test_bit(boffset / SM_SECTOR_SIZE,
 923                &ftl->cache_data_invalid_bitmap))
 924                        return -1;
 925
 926        memcpy(buffer, ftl->cache_data + boffset, SM_SECTOR_SIZE);
 927        return 0;
 928}
 929
 930/* Write the cache to hardware */
 931int sm_cache_flush(struct sm_ftl *ftl)
 932{
 933        struct ftl_zone *zone;
 934
 935        int sector_num;
 936        uint16_t write_sector;
 937        int zone_num = ftl->cache_zone;
 938        int block_num;
 939
 940        if (ftl->cache_clean)
 941                return 0;
 942
 943        if (ftl->unstable)
 944                return -EIO;
 945
 946        BUG_ON(zone_num < 0);
 947        zone = &ftl->zones[zone_num];
 948        block_num = zone->lba_to_phys_table[ftl->cache_block];
 949
 950
 951        /* Try to read all unread areas of the cache block*/
 952        for_each_set_bit(sector_num, &ftl->cache_data_invalid_bitmap,
 953                ftl->block_size / SM_SECTOR_SIZE) {
 954
 955                if (!sm_read_sector(ftl,
 956                        zone_num, block_num, sector_num * SM_SECTOR_SIZE,
 957                        ftl->cache_data + sector_num * SM_SECTOR_SIZE, NULL))
 958                                clear_bit(sector_num,
 959                                        &ftl->cache_data_invalid_bitmap);
 960        }
 961restart:
 962
 963        if (ftl->unstable)
 964                return -EIO;
 965
 966        /* If there are no spare blocks, */
 967        /* we could still continue by erasing/writing the current block,
 968                but for such worn out media it doesn't worth the trouble,
 969                        and the dangers */
 970        if (kfifo_out(&zone->free_sectors,
 971                                (unsigned char *)&write_sector, 2) != 2) {
 972                dbg("no free sectors for write!");
 973                return -EIO;
 974        }
 975
 976
 977        if (sm_write_block(ftl, ftl->cache_data, zone_num, write_sector,
 978                ftl->cache_block, ftl->cache_data_invalid_bitmap))
 979                        goto restart;
 980
 981        /* Update the FTL table */
 982        zone->lba_to_phys_table[ftl->cache_block] = write_sector;
 983
 984        /* Write succesfull, so erase and free the old block */
 985        if (block_num > 0)
 986                sm_erase_block(ftl, zone_num, block_num, 1);
 987
 988        sm_cache_init(ftl);
 989        return 0;
 990}
 991
 992
 993/* flush timer, runs a second after last write */
 994static void sm_cache_flush_timer(unsigned long data)
 995{
 996        struct sm_ftl *ftl = (struct sm_ftl *)data;
 997        queue_work(cache_flush_workqueue, &ftl->flush_work);
 998}
 999
1000/* cache flush work, kicked by timer */
1001static void sm_cache_flush_work(struct work_struct *work)
1002{
1003        struct sm_ftl *ftl = container_of(work, struct sm_ftl, flush_work);
1004        mutex_lock(&ftl->mutex);
1005        sm_cache_flush(ftl);
1006        mutex_unlock(&ftl->mutex);
1007        return;
1008}
1009
1010/* ---------------- outside interface -------------------------------------- */
1011
1012/* outside interface: read a sector */
1013static int sm_read(struct mtd_blktrans_dev *dev,
1014                   unsigned long sect_no, char *buf)
1015{
1016        struct sm_ftl *ftl = dev->priv;
1017        struct ftl_zone *zone;
1018        int error = 0, in_cache = 0;
1019        int zone_num, block, boffset;
1020
1021        sm_break_offset(ftl, sect_no << 9, &zone_num, &block, &boffset);
1022        mutex_lock(&ftl->mutex);
1023
1024
1025        zone = sm_get_zone(ftl, zone_num);
1026        if (IS_ERR(zone)) {
1027                error = PTR_ERR(zone);
1028                goto unlock;
1029        }
1030
1031        /* Have to look at cache first */
1032        if (ftl->cache_zone == zone_num && ftl->cache_block == block) {
1033                in_cache = 1;
1034                if (!sm_cache_get(ftl, buf, boffset))
1035                        goto unlock;
1036        }
1037
1038        /* Translate the block and return if doesn't exist in the table */
1039        block = zone->lba_to_phys_table[block];
1040
1041        if (block == -1) {
1042                memset(buf, 0xFF, SM_SECTOR_SIZE);
1043                goto unlock;
1044        }
1045
1046        if (sm_read_sector(ftl, zone_num, block, boffset, buf, NULL)) {
1047                error = -EIO;
1048                goto unlock;
1049        }
1050
1051        if (in_cache)
1052                sm_cache_put(ftl, buf, boffset);
1053unlock:
1054        mutex_unlock(&ftl->mutex);
1055        return error;
1056}
1057
1058/* outside interface: write a sector */
1059static int sm_write(struct mtd_blktrans_dev *dev,
1060                                unsigned long sec_no, char *buf)
1061{
1062        struct sm_ftl *ftl = dev->priv;
1063        struct ftl_zone *zone;
1064        int error, zone_num, block, boffset;
1065
1066        BUG_ON(ftl->readonly);
1067        sm_break_offset(ftl, sec_no << 9, &zone_num, &block, &boffset);
1068
1069        /* No need in flush thread running now */
1070        del_timer(&ftl->timer);
1071        mutex_lock(&ftl->mutex);
1072
1073        zone = sm_get_zone(ftl, zone_num);
1074        if (IS_ERR(zone)) {
1075                error = PTR_ERR(zone);
1076                goto unlock;
1077        }
1078
1079        /* If entry is not in cache, flush it */
1080        if (ftl->cache_block != block || ftl->cache_zone != zone_num) {
1081
1082                error = sm_cache_flush(ftl);
1083                if (error)
1084                        goto unlock;
1085
1086                ftl->cache_block = block;
1087                ftl->cache_zone = zone_num;
1088        }
1089
1090        sm_cache_put(ftl, buf, boffset);
1091unlock:
1092        mod_timer(&ftl->timer, jiffies + msecs_to_jiffies(cache_timeout));
1093        mutex_unlock(&ftl->mutex);
1094        return error;
1095}
1096
1097/* outside interface: flush everything */
1098static int sm_flush(struct mtd_blktrans_dev *dev)
1099{
1100        struct sm_ftl *ftl = dev->priv;
1101        int retval;
1102
1103        mutex_lock(&ftl->mutex);
1104        retval =  sm_cache_flush(ftl);
1105        mutex_unlock(&ftl->mutex);
1106        return retval;
1107}
1108
1109/* outside interface: device is released */
1110static int sm_release(struct mtd_blktrans_dev *dev)
1111{
1112        struct sm_ftl *ftl = dev->priv;
1113
1114        mutex_lock(&ftl->mutex);
1115        del_timer_sync(&ftl->timer);
1116        cancel_work_sync(&ftl->flush_work);
1117        sm_cache_flush(ftl);
1118        mutex_unlock(&ftl->mutex);
1119        return 0;
1120}
1121
1122/* outside interface: get geometry */
1123static int sm_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
1124{
1125        struct sm_ftl *ftl = dev->priv;
1126        geo->heads = ftl->heads;
1127        geo->sectors = ftl->sectors;
1128        geo->cylinders = ftl->cylinders;
1129        return 0;
1130}
1131
1132/* external interface: main initialization function */
1133static void sm_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
1134{
1135        struct mtd_blktrans_dev *trans;
1136        struct sm_ftl *ftl;
1137
1138        /* Allocate & initialize our private structure */
1139        ftl = kzalloc(sizeof(struct sm_ftl), GFP_KERNEL);
1140        if (!ftl)
1141                goto error1;
1142
1143
1144        mutex_init(&ftl->mutex);
1145        setup_timer(&ftl->timer, sm_cache_flush_timer, (unsigned long)ftl);
1146        INIT_WORK(&ftl->flush_work, sm_cache_flush_work);
1147        init_completion(&ftl->erase_completion);
1148
1149        /* Read media information */
1150        if (sm_get_media_info(ftl, mtd)) {
1151                dbg("found unsupported mtd device, aborting");
1152                goto error2;
1153        }
1154
1155
1156        /* Allocate temporary CIS buffer for read retry support */
1157        ftl->cis_buffer = kzalloc(SM_SECTOR_SIZE, GFP_KERNEL);
1158        if (!ftl->cis_buffer)
1159                goto error2;
1160
1161        /* Allocate zone array, it will be initialized on demand */
1162        ftl->zones = kzalloc(sizeof(struct ftl_zone) * ftl->zone_count,
1163                                                                GFP_KERNEL);
1164        if (!ftl->zones)
1165                goto error3;
1166
1167        /* Allocate the cache*/
1168        ftl->cache_data = kzalloc(ftl->block_size, GFP_KERNEL);
1169
1170        if (!ftl->cache_data)
1171                goto error4;
1172
1173        sm_cache_init(ftl);
1174
1175
1176        /* Allocate upper layer structure and initialize it */
1177        trans = kzalloc(sizeof(struct mtd_blktrans_dev), GFP_KERNEL);
1178        if (!trans)
1179                goto error5;
1180
1181        ftl->trans = trans;
1182        trans->priv = ftl;
1183
1184        trans->tr = tr;
1185        trans->mtd = mtd;
1186        trans->devnum = -1;
1187        trans->size = (ftl->block_size * ftl->max_lba * ftl->zone_count) >> 9;
1188        trans->readonly = ftl->readonly;
1189
1190        if (sm_find_cis(ftl)) {
1191                dbg("CIS not found on mtd device, aborting");
1192                goto error6;
1193        }
1194
1195        ftl->disk_attributes = sm_create_sysfs_attributes(ftl);
1196        if (!ftl->disk_attributes)
1197                goto error6;
1198        trans->disk_attributes = ftl->disk_attributes;
1199
1200        sm_printk("Found %d MiB xD/SmartMedia FTL on mtd%d",
1201                (int)(mtd->size / (1024 * 1024)), mtd->index);
1202
1203        dbg("FTL layout:");
1204        dbg("%d zone(s), each consists of %d blocks (+%d spares)",
1205                ftl->zone_count, ftl->max_lba,
1206                ftl->zone_size - ftl->max_lba);
1207        dbg("each block consists of %d bytes",
1208                ftl->block_size);
1209
1210
1211        /* Register device*/
1212        if (add_mtd_blktrans_dev(trans)) {
1213                dbg("error in mtdblktrans layer");
1214                goto error6;
1215        }
1216        return;
1217error6:
1218        kfree(trans);
1219error5:
1220        kfree(ftl->cache_data);
1221error4:
1222        kfree(ftl->zones);
1223error3:
1224        kfree(ftl->cis_buffer);
1225error2:
1226        kfree(ftl);
1227error1:
1228        return;
1229}
1230
1231/* main interface: device {surprise,} removal */
1232static void sm_remove_dev(struct mtd_blktrans_dev *dev)
1233{
1234        struct sm_ftl *ftl = dev->priv;
1235        int i;
1236
1237        del_mtd_blktrans_dev(dev);
1238        ftl->trans = NULL;
1239
1240        for (i = 0 ; i < ftl->zone_count; i++) {
1241
1242                if (!ftl->zones[i].initialized)
1243                        continue;
1244
1245                kfree(ftl->zones[i].lba_to_phys_table);
1246                kfifo_free(&ftl->zones[i].free_sectors);
1247        }
1248
1249        sm_delete_sysfs_attributes(ftl);
1250        kfree(ftl->cis_buffer);
1251        kfree(ftl->zones);
1252        kfree(ftl->cache_data);
1253        kfree(ftl);
1254}
1255
1256static struct mtd_blktrans_ops sm_ftl_ops = {
1257        .name           = "smblk",
1258        .major          = 0,
1259        .part_bits      = SM_FTL_PARTN_BITS,
1260        .blksize        = SM_SECTOR_SIZE,
1261        .getgeo         = sm_getgeo,
1262
1263        .add_mtd        = sm_add_mtd,
1264        .remove_dev     = sm_remove_dev,
1265
1266        .readsect       = sm_read,
1267        .writesect      = sm_write,
1268
1269        .flush          = sm_flush,
1270        .release        = sm_release,
1271
1272        .owner          = THIS_MODULE,
1273};
1274
1275static __init int sm_module_init(void)
1276{
1277        int error = 0;
1278        cache_flush_workqueue = create_freezable_workqueue("smflush");
1279
1280        if (IS_ERR(cache_flush_workqueue))
1281                return PTR_ERR(cache_flush_workqueue);
1282
1283        error = register_mtd_blktrans(&sm_ftl_ops);
1284        if (error)
1285                destroy_workqueue(cache_flush_workqueue);
1286        return error;
1287
1288}
1289
1290static void __exit sm_module_exit(void)
1291{
1292        destroy_workqueue(cache_flush_workqueue);
1293        deregister_mtd_blktrans(&sm_ftl_ops);
1294}
1295
1296module_init(sm_module_init);
1297module_exit(sm_module_exit);
1298
1299MODULE_LICENSE("GPL");
1300MODULE_AUTHOR("Maxim Levitsky <maximlevitsky@gmail.com>");
1301MODULE_DESCRIPTION("Smartmedia/xD mtd translation layer");
1302
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