drivers/mtd/mtdconcat.c

   1 /*
   2  * MTD device concatenation layer
   3  *
   4  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
   5  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   6  *
   7  * NAND support by Christian Gan <cgan@iders.ca>
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  *
  11  */
  12
  13 #define __UBOOT__
  14 #ifndef __UBOOT__
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/slab.h>
  18 #include <linux/sched.h>
  19 #include <linux/types.h>
  20 #include <linux/backing-dev.h>
  21 #include <asm/div64.h>
  22 #else
  23 #include <div64.h>
  24 #include <linux/compat.h>
  25 #endif
  26
  27 #include <linux/mtd/mtd.h>
  28 #include <linux/mtd/concat.h>
  29
  30 #include <ubi_uboot.h>
  31
  32 /*
  33  * Our storage structure:
  34  * Subdev points to an array of pointers to struct mtd_info objects
  35  * which is allocated along with this structure
  36  *
  37  */
  38 struct mtd_concat {
  39         struct mtd_info mtd;
  40         int num_subdev;
  41         struct mtd_info **subdev;
  42 };
  43
  44 /*
  45  * how to calculate the size required for the above structure,
  46  * including the pointer array subdev points to:
  47  */
  48 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  49         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  50
  51 /*
  52  * Given a pointer to the MTD object in the mtd_concat structure,
  53  * we can retrieve the pointer to that structure with this macro.
  54  */
  55 #define CONCAT(x)  ((struct mtd_concat *)(x))
  56
  57 /*
  58  * MTD methods which look up the relevant subdevice, translate the
  59  * effective address and pass through to the subdevice.
  60  */
  61
  62 static int
  63 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  64             size_t * retlen, u_char * buf)
  65 {
  66         struct mtd_concat *concat = CONCAT(mtd);
  67         int ret = 0, err;
  68         int i;
  69
  70 #ifdef __UBOOT__
  71         *retlen = 0;
  72 #endif
  73
  74         for (i = 0; i < concat->num_subdev; i++) {
  75                 struct mtd_info *subdev = concat->subdev[i];
  76                 size_t size, retsize;
  77
  78                 if (from >= subdev->size) {
  79                         /* Not destined for this subdev */
  80                         size = 0;
  81                         from -= subdev->size;
  82                         continue;
  83                 }
  84                 if (from + len > subdev->size)
  85                         /* First part goes into this subdev */
  86                         size = subdev->size - from;
  87                 else
  88                         /* Entire transaction goes into this subdev */
  89                         size = len;
  90
  91                 err = mtd_read(subdev, from, size, &retsize, buf);
  92
  93                 /* Save information about bitflips! */
  94                 if (unlikely(err)) {
  95                         if (mtd_is_eccerr(err)) {
  96                                 mtd->ecc_stats.failed++;
  97                                 ret = err;
  98                         } else if (mtd_is_bitflip(err)) {
  99                                 mtd->ecc_stats.corrected++;
 100                                 /* Do not overwrite -EBADMSG !! */
 101                                 if (!ret)
 102                                         ret = err;
 103                         } else
 104                                 return err;
 105                 }
 106
 107                 *retlen += retsize;
 108                 len -= size;
 109                 if (len == 0)
 110                         return ret;
 111
 112                 buf += size;
 113                 from = 0;
 114         }
 115         return -EINVAL;
 116 }
 117
 118 static int
 119 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 120              size_t * retlen, const u_char * buf)
 121 {
 122         struct mtd_concat *concat = CONCAT(mtd);
 123         int err = -EINVAL;
 124         int i;
 125
 126 #ifdef __UBOOT__
 127         *retlen = 0;
 128 #endif
 129
 130         for (i = 0; i < concat->num_subdev; i++) {
 131                 struct mtd_info *subdev = concat->subdev[i];
 132                 size_t size, retsize;
 133
 134                 if (to >= subdev->size) {
 135                         size = 0;
 136                         to -= subdev->size;
 137                         continue;
 138                 }
 139                 if (to + len > subdev->size)
 140                         size = subdev->size - to;
 141                 else
 142                         size = len;
 143
 144                 err = mtd_write(subdev, to, size, &retsize, buf);
 145                 if (err)
 146                         break;
 147
 148                 *retlen += retsize;
 149                 len -= size;
 150                 if (len == 0)
 151                         break;
 152
 153                 err = -EINVAL;
 154                 buf += size;
 155                 to = 0;
 156         }
 157         return err;
 158 }
 159
 160 #ifndef __UBOOT__
 161 static int
 162 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 163                 unsigned long count, loff_t to, size_t * retlen)
 164 {
 165         struct mtd_concat *concat = CONCAT(mtd);
 166         struct kvec *vecs_copy;
 167         unsigned long entry_low, entry_high;
 168         size_t total_len = 0;
 169         int i;
 170         int err = -EINVAL;
 171
 172         /* Calculate total length of data */
 173         for (i = 0; i < count; i++)
 174                 total_len += vecs[i].iov_len;
 175
 176         /* Check alignment */
 177         if (mtd->writesize > 1) {
 178                 uint64_t __to = to;
 179                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 180                         return -EINVAL;
 181         }
 182
 183         /* make a copy of vecs */
 184         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 185         if (!vecs_copy)
 186                 return -ENOMEM;
 187
 188         entry_low = 0;
 189         for (i = 0; i < concat->num_subdev; i++) {
 190                 struct mtd_info *subdev = concat->subdev[i];
 191                 size_t size, wsize, retsize, old_iov_len;
 192
 193                 if (to >= subdev->size) {
 194                         to -= subdev->size;
 195                         continue;
 196                 }
 197
 198                 size = min_t(uint64_t, total_len, subdev->size - to);
 199                 wsize = size; /* store for future use */
 200
 201                 entry_high = entry_low;
 202                 while (entry_high < count) {
 203                         if (size <= vecs_copy[entry_high].iov_len)
 204                                 break;
 205                         size -= vecs_copy[entry_high++].iov_len;
 206                 }
 207
 208                 old_iov_len = vecs_copy[entry_high].iov_len;
 209                 vecs_copy[entry_high].iov_len = size;
 210
 211                 err = mtd_writev(subdev, &vecs_copy[entry_low],
 212                                  entry_high - entry_low + 1, to, &retsize);
 213
 214                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 215                 vecs_copy[entry_high].iov_base += size;
 216
 217                 entry_low = entry_high;
 218
 219                 if (err)
 220                         break;
 221
 222                 *retlen += retsize;
 223                 total_len -= wsize;
 224
 225                 if (total_len == 0)
 226                         break;
 227
 228                 err = -EINVAL;
 229                 to = 0;
 230         }
 231
 232         kfree(vecs_copy);
 233         return err;
 234 }
 235 #endif
 236
 237 static int
 238 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 239 {
 240         struct mtd_concat *concat = CONCAT(mtd);
 241         struct mtd_oob_ops devops = *ops;
 242         int i, err, ret = 0;
 243
 244         ops->retlen = ops->oobretlen = 0;
 245
 246         for (i = 0; i < concat->num_subdev; i++) {
 247                 struct mtd_info *subdev = concat->subdev[i];
 248
 249                 if (from >= subdev->size) {
 250                         from -= subdev->size;
 251                         continue;
 252                 }
 253
 254                 /* partial read ? */
 255                 if (from + devops.len > subdev->size)
 256                         devops.len = subdev->size - from;
 257
 258                 err = mtd_read_oob(subdev, from, &devops);
 259                 ops->retlen += devops.retlen;
 260                 ops->oobretlen += devops.oobretlen;
 261
 262                 /* Save information about bitflips! */
 263                 if (unlikely(err)) {
 264                         if (mtd_is_eccerr(err)) {
 265                                 mtd->ecc_stats.failed++;
 266                                 ret = err;
 267                         } else if (mtd_is_bitflip(err)) {
 268                                 mtd->ecc_stats.corrected++;
 269                                 /* Do not overwrite -EBADMSG !! */
 270                                 if (!ret)
 271                                         ret = err;
 272                         } else
 273                                 return err;
 274                 }
 275
 276                 if (devops.datbuf) {
 277                         devops.len = ops->len - ops->retlen;
 278                         if (!devops.len)
 279                                 return ret;
 280                         devops.datbuf += devops.retlen;
 281                 }
 282                 if (devops.oobbuf) {
 283                         devops.ooblen = ops->ooblen - ops->oobretlen;
 284                         if (!devops.ooblen)
 285                                 return ret;
 286                         devops.oobbuf += ops->oobretlen;
 287                 }
 288
 289                 from = 0;
 290         }
 291         return -EINVAL;
 292 }
 293
 294 static int
 295 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 296 {
 297         struct mtd_concat *concat = CONCAT(mtd);
 298         struct mtd_oob_ops devops = *ops;
 299         int i, err;
 300
 301         if (!(mtd->flags & MTD_WRITEABLE))
 302                 return -EROFS;
 303
 304         ops->retlen = ops->oobretlen = 0;
 305
 306         for (i = 0; i < concat->num_subdev; i++) {
 307                 struct mtd_info *subdev = concat->subdev[i];
 308
 309                 if (to >= subdev->size) {
 310                         to -= subdev->size;
 311                         continue;
 312                 }
 313
 314                 /* partial write ? */
 315                 if (to + devops.len > subdev->size)
 316                         devops.len = subdev->size - to;
 317
 318                 err = mtd_write_oob(subdev, to, &devops);
 319                 ops->retlen += devops.oobretlen;
 320                 if (err)
 321                         return err;
 322
 323                 if (devops.datbuf) {
 324                         devops.len = ops->len - ops->retlen;
 325                         if (!devops.len)
 326                                 return 0;
 327                         devops.datbuf += devops.retlen;
 328                 }
 329                 if (devops.oobbuf) {
 330                         devops.ooblen = ops->ooblen - ops->oobretlen;
 331                         if (!devops.ooblen)
 332                                 return 0;
 333                         devops.oobbuf += devops.oobretlen;
 334                 }
 335                 to = 0;
 336         }
 337         return -EINVAL;
 338 }
 339
 340 static void concat_erase_callback(struct erase_info *instr)
 341 {
 342         /* Nothing to do here in U-Boot */
 343 #ifndef __UBOOT__
 344         wake_up((wait_queue_head_t *) instr->priv);
 345 #endif
 346 }
 347
 348 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 349 {
 350         int err;
 351         wait_queue_head_t waitq;
 352         DECLARE_WAITQUEUE(wait, current);
 353
 354         /*
 355          * This code was stol^H^H^H^Hinspired by mtdchar.c
 356          */
 357         init_waitqueue_head(&waitq);
 358
 359         erase->mtd = mtd;
 360         erase->callback = concat_erase_callback;
 361         erase->priv = (unsigned long) &waitq;
 362
 363         /*
 364          * FIXME: Allow INTERRUPTIBLE. Which means
 365          * not having the wait_queue head on the stack.
 366          */
 367         err = mtd_erase(mtd, erase);
 368         if (!err) {
 369                 set_current_state(TASK_UNINTERRUPTIBLE);
 370                 add_wait_queue(&waitq, &wait);
 371                 if (erase->state != MTD_ERASE_DONE
 372                     && erase->state != MTD_ERASE_FAILED)
 373                         schedule();
 374                 remove_wait_queue(&waitq, &wait);
 375                 set_current_state(TASK_RUNNING);
 376
 377                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 378         }
 379         return err;
 380 }
 381
 382 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 383 {
 384         struct mtd_concat *concat = CONCAT(mtd);
 385         struct mtd_info *subdev;
 386         int i, err;
 387         uint64_t length, offset = 0;
 388         struct erase_info *erase;
 389
 390         /*
 391          * Check for proper erase block alignment of the to-be-erased area.
 392          * It is easier to do this based on the super device's erase
 393          * region info rather than looking at each particular sub-device
 394          * in turn.
 395          */
 396         if (!concat->mtd.numeraseregions) {
 397                 /* the easy case: device has uniform erase block size */
 398                 if (instr->addr & (concat->mtd.erasesize - 1))
 399                         return -EINVAL;
 400                 if (instr->len & (concat->mtd.erasesize - 1))
 401                         return -EINVAL;
 402         } else {
 403                 /* device has variable erase size */
 404                 struct mtd_erase_region_info *erase_regions =
 405                     concat->mtd.eraseregions;
 406
 407                 /*
 408                  * Find the erase region where the to-be-erased area begins:
 409                  */
 410                 for (i = 0; i < concat->mtd.numeraseregions &&
 411                      instr->addr >= erase_regions[i].offset; i++) ;
 412                 --i;
 413
 414                 /*
 415                  * Now erase_regions[i] is the region in which the
 416                  * to-be-erased area begins. Verify that the starting
 417                  * offset is aligned to this region's erase size:
 418                  */
 419                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 420                         return -EINVAL;
 421
 422                 /*
 423                  * now find the erase region where the to-be-erased area ends:
 424                  */
 425                 for (; i < concat->mtd.numeraseregions &&
 426                      (instr->addr + instr->len) >= erase_regions[i].offset;
 427                      ++i) ;
 428                 --i;
 429                 /*
 430                  * check if the ending offset is aligned to this region's erase size
 431                  */
 432                 if (i < 0 || ((instr->addr + instr->len) &
 433                                         (erase_regions[i].erasesize - 1)))
 434                         return -EINVAL;
 435         }
 436
 437         /* make a local copy of instr to avoid modifying the caller's struct */
 438         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 439
 440         if (!erase)
 441                 return -ENOMEM;
 442
 443         *erase = *instr;
 444         length = instr->len;
 445
 446         /*
 447          * find the subdevice where the to-be-erased area begins, adjust
 448          * starting offset to be relative to the subdevice start
 449          */
 450         for (i = 0; i < concat->num_subdev; i++) {
 451                 subdev = concat->subdev[i];
 452                 if (subdev->size <= erase->addr) {
 453                         erase->addr -= subdev->size;
 454                         offset += subdev->size;
 455                 } else {
 456                         break;
 457                 }
 458         }
 459
 460         /* must never happen since size limit has been verified above */
 461         BUG_ON(i >= concat->num_subdev);
 462
 463         /* now do the erase: */
 464         err = 0;
 465         for (; length > 0; i++) {
 466                 /* loop for all subdevices affected by this request */
 467                 subdev = concat->subdev[i];     /* get current subdevice */
 468
 469                 /* limit length to subdevice's size: */
 470                 if (erase->addr + length > subdev->size)
 471                         erase->len = subdev->size - erase->addr;
 472                 else
 473                         erase->len = length;
 474
 475                 length -= erase->len;
 476                 if ((err = concat_dev_erase(subdev, erase))) {
 477                         /* sanity check: should never happen since
 478                          * block alignment has been checked above */
 479                         BUG_ON(err == -EINVAL);
 480                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 481                                 instr->fail_addr = erase->fail_addr + offset;
 482                         break;
 483                 }
 484                 /*
 485                  * erase->addr specifies the offset of the area to be
 486                  * erased *within the current subdevice*. It can be
 487                  * non-zero only the first time through this loop, i.e.
 488                  * for the first subdevice where blocks need to be erased.
 489                  * All the following erases must begin at the start of the
 490                  * current subdevice, i.e. at offset zero.
 491                  */
 492                 erase->addr = 0;
 493                 offset += subdev->size;
 494         }
 495         instr->state = erase->state;
 496         kfree(erase);
 497         if (err)
 498                 return err;
 499
 500         if (instr->callback)
 501                 instr->callback(instr);
 502         return 0;
 503 }
 504
 505 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 506 {
 507         struct mtd_concat *concat = CONCAT(mtd);
 508         int i, err = -EINVAL;
 509
 510         for (i = 0; i < concat->num_subdev; i++) {
 511                 struct mtd_info *subdev = concat->subdev[i];
 512                 uint64_t size;
 513
 514                 if (ofs >= subdev->size) {
 515                         size = 0;
 516                         ofs -= subdev->size;
 517                         continue;
 518                 }
 519                 if (ofs + len > subdev->size)
 520                         size = subdev->size - ofs;
 521                 else
 522                         size = len;
 523
 524                 err = mtd_lock(subdev, ofs, size);
 525                 if (err)
 526                         break;
 527
 528                 len -= size;
 529                 if (len == 0)
 530                         break;
 531
 532                 err = -EINVAL;
 533                 ofs = 0;
 534         }
 535
 536         return err;
 537 }
 538
 539 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 540 {
 541         struct mtd_concat *concat = CONCAT(mtd);
 542         int i, err = 0;
 543
 544         for (i = 0; i < concat->num_subdev; i++) {
 545                 struct mtd_info *subdev = concat->subdev[i];
 546                 uint64_t size;
 547
 548                 if (ofs >= subdev->size) {
 549                         size = 0;
 550                         ofs -= subdev->size;
 551                         continue;
 552                 }
 553                 if (ofs + len > subdev->size)
 554                         size = subdev->size - ofs;
 555                 else
 556                         size = len;
 557
 558                 err = mtd_unlock(subdev, ofs, size);
 559                 if (err)
 560                         break;
 561
 562                 len -= size;
 563                 if (len == 0)
 564                         break;
 565
 566                 err = -EINVAL;
 567                 ofs = 0;
 568         }
 569
 570         return err;
 571 }
 572
 573 static void concat_sync(struct mtd_info *mtd)
 574 {
 575         struct mtd_concat *concat = CONCAT(mtd);
 576         int i;
 577
 578         for (i = 0; i < concat->num_subdev; i++) {
 579                 struct mtd_info *subdev = concat->subdev[i];
 580                 mtd_sync(subdev);
 581         }
 582 }
 583
 584 #ifndef __UBOOT__
 585 static int concat_suspend(struct mtd_info *mtd)
 586 {
 587         struct mtd_concat *concat = CONCAT(mtd);
 588         int i, rc = 0;
 589
 590         for (i = 0; i < concat->num_subdev; i++) {
 591                 struct mtd_info *subdev = concat->subdev[i];
 592                 if ((rc = mtd_suspend(subdev)) < 0)
 593                         return rc;
 594         }
 595         return rc;
 596 }
 597
 598 static void concat_resume(struct mtd_info *mtd)
 599 {
 600         struct mtd_concat *concat = CONCAT(mtd);
 601         int i;
 602
 603         for (i = 0; i < concat->num_subdev; i++) {
 604                 struct mtd_info *subdev = concat->subdev[i];
 605                 mtd_resume(subdev);
 606         }
 607 }
 608 #endif
 609
 610 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 611 {
 612         struct mtd_concat *concat = CONCAT(mtd);
 613         int i, res = 0;
 614
 615         if (!mtd_can_have_bb(concat->subdev[0]))
 616                 return res;
 617
 618         for (i = 0; i < concat->num_subdev; i++) {
 619                 struct mtd_info *subdev = concat->subdev[i];
 620
 621                 if (ofs >= subdev->size) {
 622                         ofs -= subdev->size;
 623                         continue;
 624                 }
 625
 626                 res = mtd_block_isbad(subdev, ofs);
 627                 break;
 628         }
 629
 630         return res;
 631 }
 632
 633 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 634 {
 635         struct mtd_concat *concat = CONCAT(mtd);
 636         int i, err = -EINVAL;
 637
 638         for (i = 0; i < concat->num_subdev; i++) {
 639                 struct mtd_info *subdev = concat->subdev[i];
 640
 641                 if (ofs >= subdev->size) {
 642                         ofs -= subdev->size;
 643                         continue;
 644                 }
 645
 646                 err = mtd_block_markbad(subdev, ofs);
 647                 if (!err)
 648                         mtd->ecc_stats.badblocks++;
 649                 break;
 650         }
 651
 652         return err;
 653 }
 654
 655 /*
 656  * try to support NOMMU mmaps on concatenated devices
 657  * - we don't support subdev spanning as we can't guarantee it'll work
 658  */
 659 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 660                                               unsigned long len,
 661                                               unsigned long offset,
 662                                               unsigned long flags)
 663 {
 664         struct mtd_concat *concat = CONCAT(mtd);
 665         int i;
 666
 667         for (i = 0; i < concat->num_subdev; i++) {
 668                 struct mtd_info *subdev = concat->subdev[i];
 669
 670                 if (offset >= subdev->size) {
 671                         offset -= subdev->size;
 672                         continue;
 673                 }
 674
 675                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 676         }
 677
 678         return (unsigned long) -ENOSYS;
 679 }
 680
 681 /*
 682  * This function constructs a virtual MTD device by concatenating
 683  * num_devs MTD devices. A pointer to the new device object is
 684  * stored to *new_dev upon success. This function does _not_
 685  * register any devices: this is the caller's responsibility.
 686  */
 687 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 688                                    int num_devs,        /* number of subdevices      */
 689 #ifndef __UBOOT__
 690                                    const char *name)
 691 #else
 692                                    char *name)
 693 #endif
 694 {                               /* name for the new device   */
 695         int i;
 696         size_t size;
 697         struct mtd_concat *concat;
 698         uint32_t max_erasesize, curr_erasesize;
 699         int num_erase_region;
 700         int max_writebufsize = 0;
 701
 702         debug("Concatenating MTD devices:\n");
 703         for (i = 0; i < num_devs; i++)
 704                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 705         debug("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          * incompatibilities 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
 728         for (i = 0; i < num_devs; i++)
 729                 if (max_writebufsize < subdev[i]->writebufsize)
 730                         max_writebufsize = subdev[i]->writebufsize;
 731         concat->mtd.writebufsize = max_writebufsize;
 732
 733         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 734         concat->mtd.oobsize = subdev[0]->oobsize;
 735         concat->mtd.oobavail = subdev[0]->oobavail;
 736 #ifndef __UBOOT__
 737         if (subdev[0]->_writev)
 738                 concat->mtd._writev = concat_writev;
 739 #endif
 740         if (subdev[0]->_read_oob)
 741                 concat->mtd._read_oob = concat_read_oob;
 742         if (subdev[0]->_write_oob)
 743                 concat->mtd._write_oob = concat_write_oob;
 744         if (subdev[0]->_block_isbad)
 745                 concat->mtd._block_isbad = concat_block_isbad;
 746         if (subdev[0]->_block_markbad)
 747                 concat->mtd._block_markbad = concat_block_markbad;
 748
 749         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 750
 751 #ifndef __UBOOT__
 752         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 753 #endif
 754
 755         concat->subdev[0] = subdev[0];
 756
 757         for (i = 1; i < num_devs; i++) {
 758                 if (concat->mtd.type != subdev[i]->type) {
 759                         kfree(concat);
 760                         printk("Incompatible device type on \"%s\"\n",
 761                                subdev[i]->name);
 762                         return NULL;
 763                 }
 764                 if (concat->mtd.flags != subdev[i]->flags) {
 765                         /*
 766                          * Expect all flags except MTD_WRITEABLE to be
 767                          * equal on all subdevices.
 768                          */
 769                         if ((concat->mtd.flags ^ subdev[i]->
 770                              flags) & ~MTD_WRITEABLE) {
 771                                 kfree(concat);
 772                                 printk("Incompatible device flags on \"%s\"\n",
 773                                        subdev[i]->name);
 774                                 return NULL;
 775                         } else
 776                                 /* if writeable attribute differs,
 777                                    make super device writeable */
 778                                 concat->mtd.flags |=
 779                                     subdev[i]->flags & MTD_WRITEABLE;
 780                 }
 781
 782 #ifndef __UBOOT__
 783                 /* only permit direct mapping if the BDIs are all the same
 784                  * - copy-mapping is still permitted
 785                  */
 786                 if (concat->mtd.backing_dev_info !=
 787                     subdev[i]->backing_dev_info)
 788                         concat->mtd.backing_dev_info =
 789                                 &default_backing_dev_info;
 790 #endif
 791
 792                 concat->mtd.size += subdev[i]->size;
 793                 concat->mtd.ecc_stats.badblocks +=
 794                         subdev[i]->ecc_stats.badblocks;
 795                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 796                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 797                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 798                     !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
 799                     !concat->mtd._write_oob != !subdev[i]->_write_oob) {
 800                         kfree(concat);
 801                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 802                                subdev[i]->name);
 803                         return NULL;
 804                 }
 805                 concat->subdev[i] = subdev[i];
 806
 807         }
 808
 809         concat->mtd.ecclayout = subdev[0]->ecclayout;
 810
 811         concat->num_subdev = num_devs;
 812         concat->mtd.name = name;
 813
 814         concat->mtd._erase = concat_erase;
 815         concat->mtd._read = concat_read;
 816         concat->mtd._write = concat_write;
 817         concat->mtd._sync = concat_sync;
 818         concat->mtd._lock = concat_lock;
 819         concat->mtd._unlock = concat_unlock;
 820 #ifndef __UBOOT__
 821         concat->mtd._suspend = concat_suspend;
 822         concat->mtd._resume = concat_resume;
 823 #endif
 824         concat->mtd._get_unmapped_area = concat_get_unmapped_area;
 825
 826         /*
 827          * Combine the erase block size info of the subdevices:
 828          *
 829          * first, walk the map of the new device and see how
 830          * many changes in erase size we have
 831          */
 832         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 833         num_erase_region = 1;
 834         for (i = 0; i < num_devs; i++) {
 835                 if (subdev[i]->numeraseregions == 0) {
 836                         /* current subdevice has uniform erase size */
 837                         if (subdev[i]->erasesize != curr_erasesize) {
 838                                 /* if it differs from the last subdevice's erase size, count it */
 839                                 ++num_erase_region;
 840                                 curr_erasesize = subdev[i]->erasesize;
 841                                 if (curr_erasesize > max_erasesize)
 842                                         max_erasesize = curr_erasesize;
 843                         }
 844                 } else {
 845                         /* current subdevice has variable erase size */
 846                         int j;
 847                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 848
 849                                 /* walk the list of erase regions, count any changes */
 850                                 if (subdev[i]->eraseregions[j].erasesize !=
 851                                     curr_erasesize) {
 852                                         ++num_erase_region;
 853                                         curr_erasesize =
 854                                             subdev[i]->eraseregions[j].
 855                                             erasesize;
 856                                         if (curr_erasesize > max_erasesize)
 857                                                 max_erasesize = curr_erasesize;
 858                                 }
 859                         }
 860                 }
 861         }
 862
 863         if (num_erase_region == 1) {
 864                 /*
 865                  * All subdevices have the same uniform erase size.
 866                  * This is easy:
 867                  */
 868                 concat->mtd.erasesize = curr_erasesize;
 869                 concat->mtd.numeraseregions = 0;
 870         } else {
 871                 uint64_t tmp64;
 872
 873                 /*
 874                  * erase block size varies across the subdevices: allocate
 875                  * space to store the data describing the variable erase regions
 876                  */
 877                 struct mtd_erase_region_info *erase_region_p;
 878                 uint64_t begin, position;
 879
 880                 concat->mtd.erasesize = max_erasesize;
 881                 concat->mtd.numeraseregions = num_erase_region;
 882                 concat->mtd.eraseregions = erase_region_p =
 883                     kmalloc(num_erase_region *
 884                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 885                 if (!erase_region_p) {
 886                         kfree(concat);
 887                         printk
 888                             ("memory allocation error while creating erase region list"
 889                              " for device \"%s\"\n", name);
 890                         return NULL;
 891                 }
 892
 893                 /*
 894                  * walk the map of the new device once more and fill in
 895                  * in erase region info:
 896                  */
 897                 curr_erasesize = subdev[0]->erasesize;
 898                 begin = position = 0;
 899                 for (i = 0; i < num_devs; i++) {
 900                         if (subdev[i]->numeraseregions == 0) {
 901                                 /* current subdevice has uniform erase size */
 902                                 if (subdev[i]->erasesize != curr_erasesize) {
 903                                         /*
 904                                          *  fill in an mtd_erase_region_info structure for the area
 905                                          *  we have walked so far:
 906                                          */
 907                                         erase_region_p->offset = begin;
 908                                         erase_region_p->erasesize =
 909                                             curr_erasesize;
 910                                         tmp64 = position - begin;
 911                                         do_div(tmp64, curr_erasesize);
 912                                         erase_region_p->numblocks = tmp64;
 913                                         begin = position;
 914
 915                                         curr_erasesize = subdev[i]->erasesize;
 916                                         ++erase_region_p;
 917                                 }
 918                                 position += subdev[i]->size;
 919                         } else {
 920                                 /* current subdevice has variable erase size */
 921                                 int j;
 922                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 923                                         /* walk the list of erase regions, count any changes */
 924                                         if (subdev[i]->eraseregions[j].
 925                                             erasesize != curr_erasesize) {
 926                                                 erase_region_p->offset = begin;
 927                                                 erase_region_p->erasesize =
 928                                                     curr_erasesize;
 929                                                 tmp64 = position - begin;
 930                                                 do_div(tmp64, curr_erasesize);
 931                                                 erase_region_p->numblocks = tmp64;
 932                                                 begin = position;
 933
 934                                                 curr_erasesize =
 935                                                     subdev[i]->eraseregions[j].
 936                                                     erasesize;
 937                                                 ++erase_region_p;
 938                                         }
 939                                         position +=
 940                                             subdev[i]->eraseregions[j].
 941                                             numblocks * (uint64_t)curr_erasesize;
 942                                 }
 943                         }
 944                 }
 945                 /* Now write the final entry */
 946                 erase_region_p->offset = begin;
 947                 erase_region_p->erasesize = curr_erasesize;
 948                 tmp64 = position - begin;
 949                 do_div(tmp64, curr_erasesize);
 950                 erase_region_p->numblocks = tmp64;
 951         }
 952
 953         return &concat->mtd;
 954 }
 955
 956 /*
 957  * This function destroys an MTD object obtained from concat_mtd_devs()
 958  */
 959
 960 void mtd_concat_destroy(struct mtd_info *mtd)
 961 {
 962         struct mtd_concat *concat = CONCAT(mtd);
 963         if (concat->mtd.numeraseregions)
 964                 kfree(concat->mtd.eraseregions);
 965         kfree(concat);
 966 }
 967
 968 EXPORT_SYMBOL(mtd_concat_create);
 969 EXPORT_SYMBOL(mtd_concat_destroy);
 970
 971 MODULE_LICENSE("GPL");
 972 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 973 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");