linux/drivers/mtd/mtdconcat.c
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   1/*
   2 * MTD device concatenation layer
   3 *
   4 * (C) 2002 Robert Kaiser <rkaiser@sysgo.de>
   5 *
   6 * NAND support by Christian Gan <cgan@iders.ca>
   7 *
   8 * This code is GPL
   9 */
  10
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/slab.h>
  14#include <linux/sched.h>
  15#include <linux/types.h>
  16
  17#include <linux/mtd/mtd.h>
  18#include <linux/mtd/concat.h>
  19
  20#include <asm/div64.h>
  21
  22/*
  23 * Our storage structure:
  24 * Subdev points to an array of pointers to struct mtd_info objects
  25 * which is allocated along with this structure
  26 *
  27 */
  28struct mtd_concat {
  29        struct mtd_info mtd;
  30        int num_subdev;
  31        struct mtd_info **subdev;
  32};
  33
  34/*
  35 * how to calculate the size required for the above structure,
  36 * including the pointer array subdev points to:
  37 */
  38#define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  39        ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  40
  41/*
  42 * Given a pointer to the MTD object in the mtd_concat structure,
  43 * we can retrieve the pointer to that structure with this macro.
  44 */
  45#define CONCAT(x)  ((struct mtd_concat *)(x))
  46
  47/*
  48 * MTD methods which look up the relevant subdevice, translate the
  49 * effective address and pass through to the subdevice.
  50 */
  51
  52static int
  53concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  54            size_t * retlen, u_char * buf)
  55{
  56        struct mtd_concat *concat = CONCAT(mtd);
  57        int ret = 0, err;
  58        int i;
  59
  60        *retlen = 0;
  61
  62        for (i = 0; i < concat->num_subdev; i++) {
  63                struct mtd_info *subdev = concat->subdev[i];
  64                size_t size, retsize;
  65
  66                if (from >= subdev->size) {
  67                        /* Not destined for this subdev */
  68                        size = 0;
  69                        from -= subdev->size;
  70                        continue;
  71                }
  72                if (from + len > subdev->size)
  73                        /* First part goes into this subdev */
  74                        size = subdev->size - from;
  75                else
  76                        /* Entire transaction goes into this subdev */
  77                        size = len;
  78
  79                err = subdev->read(subdev, from, size, &retsize, buf);
  80
  81                /* Save information about bitflips! */
  82                if (unlikely(err)) {
  83                        if (err == -EBADMSG) {
  84                                mtd->ecc_stats.failed++;
  85                                ret = err;
  86                        } else if (err == -EUCLEAN) {
  87                                mtd->ecc_stats.corrected++;
  88                                /* Do not overwrite -EBADMSG !! */
  89                                if (!ret)
  90                                        ret = err;
  91                        } else
  92                                return err;
  93                }
  94
  95                *retlen += retsize;
  96                len -= size;
  97                if (len == 0)
  98                        return ret;
  99
 100                buf += size;
 101                from = 0;
 102        }
 103        return -EINVAL;
 104}
 105
 106static int
 107concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 108             size_t * retlen, const u_char * buf)
 109{
 110        struct mtd_concat *concat = CONCAT(mtd);
 111        int err = -EINVAL;
 112        int i;
 113
 114        if (!(mtd->flags & MTD_WRITEABLE))
 115                return -EROFS;
 116
 117        *retlen = 0;
 118
 119        for (i = 0; i < concat->num_subdev; i++) {
 120                struct mtd_info *subdev = concat->subdev[i];
 121                size_t size, retsize;
 122
 123                if (to >= subdev->size) {
 124                        size = 0;
 125                        to -= subdev->size;
 126                        continue;
 127                }
 128                if (to + len > subdev->size)
 129                        size = subdev->size - to;
 130                else
 131                        size = len;
 132
 133                if (!(subdev->flags & MTD_WRITEABLE))
 134                        err = -EROFS;
 135                else
 136                        err = subdev->write(subdev, to, size, &retsize, buf);
 137
 138                if (err)
 139                        break;
 140
 141                *retlen += retsize;
 142                len -= size;
 143                if (len == 0)
 144                        break;
 145
 146                err = -EINVAL;
 147                buf += size;
 148                to = 0;
 149        }
 150        return err;
 151}
 152
 153static int
 154concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 155                unsigned long count, loff_t to, size_t * retlen)
 156{
 157        struct mtd_concat *concat = CONCAT(mtd);
 158        struct kvec *vecs_copy;
 159        unsigned long entry_low, entry_high;
 160        size_t total_len = 0;
 161        int i;
 162        int err = -EINVAL;
 163
 164        if (!(mtd->flags & MTD_WRITEABLE))
 165                return -EROFS;
 166
 167        *retlen = 0;
 168
 169        /* Calculate total length of data */
 170        for (i = 0; i < count; i++)
 171                total_len += vecs[i].iov_len;
 172
 173        /* Do not allow write past end of device */
 174        if ((to + total_len) > mtd->size)
 175                return -EINVAL;
 176
 177        /* Check alignment */
 178        if (mtd->writesize > 1) {
 179                uint64_t __to = to;
 180                if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 181                        return -EINVAL;
 182        }
 183
 184        /* make a copy of vecs */
 185        vecs_copy = kmalloc(sizeof(struct kvec) * count, GFP_KERNEL);
 186        if (!vecs_copy)
 187                return -ENOMEM;
 188        memcpy(vecs_copy, vecs, sizeof(struct kvec) * count);
 189
 190        entry_low = 0;
 191        for (i = 0; i < concat->num_subdev; i++) {
 192                struct mtd_info *subdev = concat->subdev[i];
 193                size_t size, wsize, retsize, old_iov_len;
 194
 195                if (to >= subdev->size) {
 196                        to -= subdev->size;
 197                        continue;
 198                }
 199
 200                size = min(total_len, (size_t)(subdev->size - to));
 201                wsize = size; /* store for future use */
 202
 203                entry_high = entry_low;
 204                while (entry_high < count) {
 205                        if (size <= vecs_copy[entry_high].iov_len)
 206                                break;
 207                        size -= vecs_copy[entry_high++].iov_len;
 208                }
 209
 210                old_iov_len = vecs_copy[entry_high].iov_len;
 211                vecs_copy[entry_high].iov_len = size;
 212
 213                if (!(subdev->flags & MTD_WRITEABLE))
 214                        err = -EROFS;
 215                else
 216                        err = subdev->writev(subdev, &vecs_copy[entry_low],
 217                                entry_high - entry_low + 1, to, &retsize);
 218
 219                vecs_copy[entry_high].iov_len = old_iov_len - size;
 220                vecs_copy[entry_high].iov_base += size;
 221
 222                entry_low = entry_high;
 223
 224                if (err)
 225                        break;
 226
 227                *retlen += retsize;
 228                total_len -= wsize;
 229
 230                if (total_len == 0)
 231                        break;
 232
 233                err = -EINVAL;
 234                to = 0;
 235        }
 236
 237        kfree(vecs_copy);
 238        return err;
 239}
 240
 241static int
 242concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 243{
 244        struct mtd_concat *concat = CONCAT(mtd);
 245        struct mtd_oob_ops devops = *ops;
 246        int i, err, ret = 0;
 247
 248        ops->retlen = ops->oobretlen = 0;
 249
 250        for (i = 0; i < concat->num_subdev; i++) {
 251                struct mtd_info *subdev = concat->subdev[i];
 252
 253                if (from >= subdev->size) {
 254                        from -= subdev->size;
 255                        continue;
 256                }
 257
 258                /* partial read ? */
 259                if (from + devops.len > subdev->size)
 260                        devops.len = subdev->size - from;
 261
 262                err = subdev->read_oob(subdev, from, &devops);
 263                ops->retlen += devops.retlen;
 264                ops->oobretlen += devops.oobretlen;
 265
 266                /* Save information about bitflips! */
 267                if (unlikely(err)) {
 268                        if (err == -EBADMSG) {
 269                                mtd->ecc_stats.failed++;
 270                                ret = err;
 271                        } else if (err == -EUCLEAN) {
 272                                mtd->ecc_stats.corrected++;
 273                                /* Do not overwrite -EBADMSG !! */
 274                                if (!ret)
 275                                        ret = err;
 276                        } else
 277                                return err;
 278                }
 279
 280                if (devops.datbuf) {
 281                        devops.len = ops->len - ops->retlen;
 282                        if (!devops.len)
 283                                return ret;
 284                        devops.datbuf += devops.retlen;
 285                }
 286                if (devops.oobbuf) {
 287                        devops.ooblen = ops->ooblen - ops->oobretlen;
 288                        if (!devops.ooblen)
 289                                return ret;
 290                        devops.oobbuf += ops->oobretlen;
 291                }
 292
 293                from = 0;
 294        }
 295        return -EINVAL;
 296}
 297
 298static int
 299concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 300{
 301        struct mtd_concat *concat = CONCAT(mtd);
 302        struct mtd_oob_ops devops = *ops;
 303        int i, err;
 304
 305        if (!(mtd->flags & MTD_WRITEABLE))
 306                return -EROFS;
 307
 308        ops->retlen = 0;
 309
 310        for (i = 0; i < concat->num_subdev; i++) {
 311                struct mtd_info *subdev = concat->subdev[i];
 312
 313                if (to >= subdev->size) {
 314                        to -= subdev->size;
 315                        continue;
 316                }
 317
 318                /* partial write ? */
 319                if (to + devops.len > subdev->size)
 320                        devops.len = subdev->size - to;
 321
 322                err = subdev->write_oob(subdev, to, &devops);
 323                ops->retlen += devops.retlen;
 324                if (err)
 325                        return err;
 326
 327                if (devops.datbuf) {
 328                        devops.len = ops->len - ops->retlen;
 329                        if (!devops.len)
 330                                return 0;
 331                        devops.datbuf += devops.retlen;
 332                }
 333                if (devops.oobbuf) {
 334                        devops.ooblen = ops->ooblen - ops->oobretlen;
 335                        if (!devops.ooblen)
 336                                return 0;
 337                        devops.oobbuf += devops.oobretlen;
 338                }
 339                to = 0;
 340        }
 341        return -EINVAL;
 342}
 343
 344static void concat_erase_callback(struct erase_info *instr)
 345{
 346        wake_up((wait_queue_head_t *) instr->priv);
 347}
 348
 349static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 350{
 351        int err;
 352        wait_queue_head_t waitq;
 353        DECLARE_WAITQUEUE(wait, current);
 354
 355        /*
 356         * This code was stol^H^H^H^Hinspired by mtdchar.c
 357         */
 358        init_waitqueue_head(&waitq);
 359
 360        erase->mtd = mtd;
 361        erase->callback = concat_erase_callback;
 362        erase->priv = (unsigned long) &waitq;
 363
 364        /*
 365         * FIXME: Allow INTERRUPTIBLE. Which means
 366         * not having the wait_queue head on the stack.
 367         */
 368        err = mtd->erase(mtd, erase);
 369        if (!err) {
 370                set_current_state(TASK_UNINTERRUPTIBLE);
 371                add_wait_queue(&waitq, &wait);
 372                if (erase->state != MTD_ERASE_DONE
 373                    && erase->state != MTD_ERASE_FAILED)
 374                        schedule();
 375                remove_wait_queue(&waitq, &wait);
 376                set_current_state(TASK_RUNNING);
 377
 378                err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 379        }
 380        return err;
 381}
 382
 383static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 384{
 385        struct mtd_concat *concat = CONCAT(mtd);
 386        struct mtd_info *subdev;
 387        int i, err;
 388        u_int32_t length, offset = 0;
 389        struct erase_info *erase;
 390
 391        if (!(mtd->flags & MTD_WRITEABLE))
 392                return -EROFS;
 393
 394        if (instr->addr > concat->mtd.size)
 395                return -EINVAL;
 396
 397        if (instr->len + instr->addr > concat->mtd.size)
 398                return -EINVAL;
 399
 400        /*
 401         * Check for proper erase block alignment of the to-be-erased area.
 402         * It is easier to do this based on the super device's erase
 403         * region info rather than looking at each particular sub-device
 404         * in turn.
 405         */
 406        if (!concat->mtd.numeraseregions) {
 407                /* the easy case: device has uniform erase block size */
 408                if (instr->addr & (concat->mtd.erasesize - 1))
 409                        return -EINVAL;
 410                if (instr->len & (concat->mtd.erasesize - 1))
 411                        return -EINVAL;
 412        } else {
 413                /* device has variable erase size */
 414                struct mtd_erase_region_info *erase_regions =
 415                    concat->mtd.eraseregions;
 416
 417                /*
 418                 * Find the erase region where the to-be-erased area begins:
 419                 */
 420                for (i = 0; i < concat->mtd.numeraseregions &&
 421                     instr->addr >= erase_regions[i].offset; i++) ;
 422                --i;
 423
 424                /*
 425                 * Now erase_regions[i] is the region in which the
 426                 * to-be-erased area begins. Verify that the starting
 427                 * offset is aligned to this region's erase size:
 428                 */
 429                if (instr->addr & (erase_regions[i].erasesize - 1))
 430                        return -EINVAL;
 431
 432                /*
 433                 * now find the erase region where the to-be-erased area ends:
 434                 */
 435                for (; i < concat->mtd.numeraseregions &&
 436                     (instr->addr + instr->len) >= erase_regions[i].offset;
 437                     ++i) ;
 438                --i;
 439                /*
 440                 * check if the ending offset is aligned to this region's erase size
 441                 */
 442                if ((instr->addr + instr->len) & (erase_regions[i].erasesize -
 443                                                  1))
 444                        return -EINVAL;
 445        }
 446
 447        instr->fail_addr = MTD_FAIL_ADDR_UNKNOWN;
 448
 449        /* make a local copy of instr to avoid modifying the caller's struct */
 450        erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 451
 452        if (!erase)
 453                return -ENOMEM;
 454
 455        *erase = *instr;
 456        length = instr->len;
 457
 458        /*
 459         * find the subdevice where the to-be-erased area begins, adjust
 460         * starting offset to be relative to the subdevice start
 461         */
 462        for (i = 0; i < concat->num_subdev; i++) {
 463                subdev = concat->subdev[i];
 464                if (subdev->size <= erase->addr) {
 465                        erase->addr -= subdev->size;
 466                        offset += subdev->size;
 467                } else {
 468                        break;
 469                }
 470        }
 471
 472        /* must never happen since size limit has been verified above */
 473        BUG_ON(i >= concat->num_subdev);
 474
 475        /* now do the erase: */
 476        err = 0;
 477        for (; length > 0; i++) {
 478                /* loop for all subdevices affected by this request */
 479                subdev = concat->subdev[i];     /* get current subdevice */
 480
 481                /* limit length to subdevice's size: */
 482                if (erase->addr + length > subdev->size)
 483                        erase->len = subdev->size - erase->addr;
 484                else
 485                        erase->len = length;
 486
 487                if (!(subdev->flags & MTD_WRITEABLE)) {
 488                        err = -EROFS;
 489                        break;
 490                }
 491                length -= erase->len;
 492                if ((err = concat_dev_erase(subdev, erase))) {
 493                        /* sanity check: should never happen since
 494                         * block alignment has been checked above */
 495                        BUG_ON(err == -EINVAL);
 496                        if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 497                                instr->fail_addr = erase->fail_addr + offset;
 498                        break;
 499                }
 500                /*
 501                 * erase->addr specifies the offset of the area to be
 502                 * erased *within the current subdevice*. It can be
 503                 * non-zero only the first time through this loop, i.e.
 504                 * for the first subdevice where blocks need to be erased.
 505                 * All the following erases must begin at the start of the
 506                 * current subdevice, i.e. at offset zero.
 507                 */
 508                erase->addr = 0;
 509                offset += subdev->size;
 510        }
 511        instr->state = erase->state;
 512        kfree(erase);
 513        if (err)
 514                return err;
 515
 516        if (instr->callback)
 517                instr->callback(instr);
 518        return 0;
 519}
 520
 521static int concat_lock(struct mtd_info *mtd, loff_t ofs, size_t len)
 522{
 523        struct mtd_concat *concat = CONCAT(mtd);
 524        int i, err = -EINVAL;
 525
 526        if ((len + ofs) > mtd->size)
 527                return -EINVAL;
 528
 529        for (i = 0; i < concat->num_subdev; i++) {
 530                struct mtd_info *subdev = concat->subdev[i];
 531                size_t size;
 532
 533                if (ofs >= subdev->size) {
 534                        size = 0;
 535                        ofs -= subdev->size;
 536                        continue;
 537                }
 538                if (ofs + len > subdev->size)
 539                        size = subdev->size - ofs;
 540                else
 541                        size = len;
 542
 543                err = subdev->lock(subdev, ofs, size);
 544
 545                if (err)
 546                        break;
 547
 548                len -= size;
 549                if (len == 0)
 550                        break;
 551
 552                err = -EINVAL;
 553                ofs = 0;
 554        }
 555
 556        return err;
 557}
 558
 559static int concat_unlock(struct mtd_info *mtd, loff_t ofs, size_t len)
 560{
 561        struct mtd_concat *concat = CONCAT(mtd);
 562        int i, err = 0;
 563
 564        if ((len + ofs) > mtd->size)
 565                return -EINVAL;
 566
 567        for (i = 0; i < concat->num_subdev; i++) {
 568                struct mtd_info *subdev = concat->subdev[i];
 569                size_t size;
 570
 571                if (ofs >= subdev->size) {
 572                        size = 0;
 573                        ofs -= subdev->size;
 574                        continue;
 575                }
 576                if (ofs + len > subdev->size)
 577                        size = subdev->size - ofs;
 578                else
 579                        size = len;
 580
 581                err = subdev->unlock(subdev, ofs, size);
 582
 583                if (err)
 584                        break;
 585
 586                len -= size;
 587                if (len == 0)
 588                        break;
 589
 590                err = -EINVAL;
 591                ofs = 0;
 592        }
 593
 594        return err;
 595}
 596
 597static void concat_sync(struct mtd_info *mtd)
 598{
 599        struct mtd_concat *concat = CONCAT(mtd);
 600        int i;
 601
 602        for (i = 0; i < concat->num_subdev; i++) {
 603                struct mtd_info *subdev = concat->subdev[i];
 604                subdev->sync(subdev);
 605        }
 606}
 607
 608static int concat_suspend(struct mtd_info *mtd)
 609{
 610        struct mtd_concat *concat = CONCAT(mtd);
 611        int i, rc = 0;
 612
 613        for (i = 0; i < concat->num_subdev; i++) {
 614                struct mtd_info *subdev = concat->subdev[i];
 615                if ((rc = subdev->suspend(subdev)) < 0)
 616                        return rc;
 617        }
 618        return rc;
 619}
 620
 621static void concat_resume(struct mtd_info *mtd)
 622{
 623        struct mtd_concat *concat = CONCAT(mtd);
 624        int i;
 625
 626        for (i = 0; i < concat->num_subdev; i++) {
 627                struct mtd_info *subdev = concat->subdev[i];
 628                subdev->resume(subdev);
 629        }
 630}
 631
 632static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 633{
 634        struct mtd_concat *concat = CONCAT(mtd);
 635        int i, res = 0;
 636
 637        if (!concat->subdev[0]->block_isbad)
 638                return res;
 639
 640        if (ofs > mtd->size)
 641                return -EINVAL;
 642
 643        for (i = 0; i < concat->num_subdev; i++) {
 644                struct mtd_info *subdev = concat->subdev[i];
 645
 646                if (ofs >= subdev->size) {
 647                        ofs -= subdev->size;
 648                        continue;
 649                }
 650
 651                res = subdev->block_isbad(subdev, ofs);
 652                break;
 653        }
 654
 655        return res;
 656}
 657
 658static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 659{
 660        struct mtd_concat *concat = CONCAT(mtd);
 661        int i, err = -EINVAL;
 662
 663        if (!concat->subdev[0]->block_markbad)
 664                return 0;
 665
 666        if (ofs > mtd->size)
 667                return -EINVAL;
 668
 669        for (i = 0; i < concat->num_subdev; i++) {
 670                struct mtd_info *subdev = concat->subdev[i];
 671
 672                if (ofs >= subdev->size) {
 673                        ofs -= subdev->size;
 674                        continue;
 675                }
 676
 677                err = subdev->block_markbad(subdev, ofs);
 678                if (!err)
 679                        mtd->ecc_stats.badblocks++;
 680                break;
 681        }
 682
 683        return err;
 684}
 685
 686/*
 687 * This function constructs a virtual MTD device by concatenating
 688 * num_devs MTD devices. A pointer to the new device object is
 689 * stored to *new_dev upon success. This function does _not_
 690 * register any devices: this is the caller's responsibility.
 691 */
 692struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 693                                   int num_devs,        /* number of subdevices      */
 694                                   char *name)
 695{                               /* name for the new device   */
 696        int i;
 697        size_t size;
 698        struct mtd_concat *concat;
 699        u_int32_t max_erasesize, curr_erasesize;
 700        int num_erase_region;
 701
 702        printk(KERN_NOTICE "Concatenating MTD devices:\n");
 703        for (i = 0; i < num_devs; i++)
 704                printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 705        printk(KERN_NOTICE "into device \"%s\"\n", name);
 706
 707        /* allocate the device structure */
 708        size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 709        concat = kzalloc(size, GFP_KERNEL);
 710        if (!concat) {
 711                printk
 712                    ("memory allocation error while creating concatenated device \"%s\"\n",
 713                     name);
 714                return NULL;
 715        }
 716        concat->subdev = (struct mtd_info **) (concat + 1);
 717
 718        /*
 719         * Set up the new "super" device's MTD object structure, check for
 720         * incompatibilites between the subdevices.
 721         */
 722        concat->mtd.type = subdev[0]->type;
 723        concat->mtd.flags = subdev[0]->flags;
 724        concat->mtd.size = subdev[0]->size;
 725        concat->mtd.erasesize = subdev[0]->erasesize;
 726        concat->mtd.writesize = subdev[0]->writesize;
 727        concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 728        concat->mtd.oobsize = subdev[0]->oobsize;
 729        concat->mtd.oobavail = subdev[0]->oobavail;
 730        if (subdev[0]->writev)
 731                concat->mtd.writev = concat_writev;
 732        if (subdev[0]->read_oob)
 733                concat->mtd.read_oob = concat_read_oob;
 734        if (subdev[0]->write_oob)
 735                concat->mtd.write_oob = concat_write_oob;
 736        if (subdev[0]->block_isbad)
 737                concat->mtd.block_isbad = concat_block_isbad;
 738        if (subdev[0]->block_markbad)
 739                concat->mtd.block_markbad = concat_block_markbad;
 740
 741        concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 742
 743        concat->subdev[0] = subdev[0];
 744
 745        for (i = 1; i < num_devs; i++) {
 746                if (concat->mtd.type != subdev[i]->type) {
 747                        kfree(concat);
 748                        printk("Incompatible device type on \"%s\"\n",
 749                               subdev[i]->name);
 750                        return NULL;
 751                }
 752                if (concat->mtd.flags != subdev[i]->flags) {
 753                        /*
 754                         * Expect all flags except MTD_WRITEABLE to be
 755                         * equal on all subdevices.
 756                         */
 757                        if ((concat->mtd.flags ^ subdev[i]->
 758                             flags) & ~MTD_WRITEABLE) {
 759                                kfree(concat);
 760                                printk("Incompatible device flags on \"%s\"\n",
 761                                       subdev[i]->name);
 762                                return NULL;
 763                        } else
 764                                /* if writeable attribute differs,
 765                                   make super device writeable */
 766                                concat->mtd.flags |=
 767                                    subdev[i]->flags & MTD_WRITEABLE;
 768                }
 769                concat->mtd.size += subdev[i]->size;
 770                concat->mtd.ecc_stats.badblocks +=
 771                        subdev[i]->ecc_stats.badblocks;
 772                if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 773                    concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 774                    concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 775                    !concat->mtd.read_oob  != !subdev[i]->read_oob ||
 776                    !concat->mtd.write_oob != !subdev[i]->write_oob) {
 777                        kfree(concat);
 778                        printk("Incompatible OOB or ECC data on \"%s\"\n",
 779                               subdev[i]->name);
 780                        return NULL;
 781                }
 782                concat->subdev[i] = subdev[i];
 783
 784        }
 785
 786        concat->mtd.ecclayout = subdev[0]->ecclayout;
 787
 788        concat->num_subdev = num_devs;
 789        concat->mtd.name = name;
 790
 791        concat->mtd.erase = concat_erase;
 792        concat->mtd.read = concat_read;
 793        concat->mtd.write = concat_write;
 794        concat->mtd.sync = concat_sync;
 795        concat->mtd.lock = concat_lock;
 796        concat->mtd.unlock = concat_unlock;
 797        concat->mtd.suspend = concat_suspend;
 798        concat->mtd.resume = concat_resume;
 799
 800        /*
 801         * Combine the erase block size info of the subdevices:
 802         *
 803         * first, walk the map of the new device and see how
 804         * many changes in erase size we have
 805         */
 806        max_erasesize = curr_erasesize = subdev[0]->erasesize;
 807        num_erase_region = 1;
 808        for (i = 0; i < num_devs; i++) {
 809                if (subdev[i]->numeraseregions == 0) {
 810                        /* current subdevice has uniform erase size */
 811                        if (subdev[i]->erasesize != curr_erasesize) {
 812                                /* if it differs from the last subdevice's erase size, count it */
 813                                ++num_erase_region;
 814                                curr_erasesize = subdev[i]->erasesize;
 815                                if (curr_erasesize > max_erasesize)
 816                                        max_erasesize = curr_erasesize;
 817                        }
 818                } else {
 819                        /* current subdevice has variable erase size */
 820                        int j;
 821                        for (j = 0; j < subdev[i]->numeraseregions; j++) {
 822
 823                                /* walk the list of erase regions, count any changes */
 824                                if (subdev[i]->eraseregions[j].erasesize !=
 825                                    curr_erasesize) {
 826                                        ++num_erase_region;
 827                                        curr_erasesize =
 828                                            subdev[i]->eraseregions[j].
 829                                            erasesize;
 830                                        if (curr_erasesize > max_erasesize)
 831                                                max_erasesize = curr_erasesize;
 832                                }
 833                        }
 834                }
 835        }
 836
 837        if (num_erase_region == 1) {
 838                /*
 839                 * All subdevices have the same uniform erase size.
 840                 * This is easy:
 841                 */
 842                concat->mtd.erasesize = curr_erasesize;
 843                concat->mtd.numeraseregions = 0;
 844        } else {
 845                /*
 846                 * erase block size varies across the subdevices: allocate
 847                 * space to store the data describing the variable erase regions
 848                 */
 849                struct mtd_erase_region_info *erase_region_p;
 850                u_int32_t begin, position;
 851
 852                concat->mtd.erasesize = max_erasesize;
 853                concat->mtd.numeraseregions = num_erase_region;
 854                concat->mtd.eraseregions = erase_region_p =
 855                    kmalloc(num_erase_region *
 856                            sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 857                if (!erase_region_p) {
 858                        kfree(concat);
 859                        printk
 860                            ("memory allocation error while creating erase region list"
 861                             " for device \"%s\"\n", name);
 862                        return NULL;
 863                }
 864
 865                /*
 866                 * walk the map of the new device once more and fill in
 867                 * in erase region info:
 868                 */
 869                curr_erasesize = subdev[0]->erasesize;
 870                begin = position = 0;
 871                for (i = 0; i < num_devs; i++) {
 872                        if (subdev[i]->numeraseregions == 0) {
 873                                /* current subdevice has uniform erase size */
 874                                if (subdev[i]->erasesize != curr_erasesize) {
 875                                        /*
 876                                         *  fill in an mtd_erase_region_info structure for the area
 877                                         *  we have walked so far:
 878                                         */
 879                                        erase_region_p->offset = begin;
 880                                        erase_region_p->erasesize =
 881                                            curr_erasesize;
 882                                        erase_region_p->numblocks =
 883                                            (position - begin) / curr_erasesize;
 884                                        begin = position;
 885
 886                                        curr_erasesize = subdev[i]->erasesize;
 887                                        ++erase_region_p;
 888                                }
 889                                position += subdev[i]->size;
 890                        } else {
 891                                /* current subdevice has variable erase size */
 892                                int j;
 893                                for (j = 0; j < subdev[i]->numeraseregions; j++) {
 894                                        /* walk the list of erase regions, count any changes */
 895                                        if (subdev[i]->eraseregions[j].
 896                                            erasesize != curr_erasesize) {
 897                                                erase_region_p->offset = begin;
 898                                                erase_region_p->erasesize =
 899                                                    curr_erasesize;
 900                                                erase_region_p->numblocks =
 901                                                    (position -
 902                                                     begin) / curr_erasesize;
 903                                                begin = position;
 904
 905                                                curr_erasesize =
 906                                                    subdev[i]->eraseregions[j].
 907                                                    erasesize;
 908                                                ++erase_region_p;
 909                                        }
 910                                        position +=
 911                                            subdev[i]->eraseregions[j].
 912                                            numblocks * curr_erasesize;
 913                                }
 914                        }
 915                }
 916                /* Now write the final entry */
 917                erase_region_p->offset = begin;
 918                erase_region_p->erasesize = curr_erasesize;
 919                erase_region_p->numblocks = (position - begin) / curr_erasesize;
 920        }
 921
 922        return &concat->mtd;
 923}
 924
 925/*
 926 * This function destroys an MTD object obtained from concat_mtd_devs()
 927 */
 928
 929void mtd_concat_destroy(struct mtd_info *mtd)
 930{
 931        struct mtd_concat *concat = CONCAT(mtd);
 932        if (concat->mtd.numeraseregions)
 933                kfree(concat->mtd.eraseregions);
 934        kfree(concat);
 935}
 936
 937EXPORT_SYMBOL(mtd_concat_create);
 938EXPORT_SYMBOL(mtd_concat_destroy);
 939
 940MODULE_LICENSE("GPL");
 941MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 942MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");
 943