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 #ifndef __UBOOT__
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/slab.h>
  17 #include <linux/sched.h>
  18 #include <linux/types.h>
  19 #include <linux/backing-dev.h>
  20 #include <asm/div64.h>
  21 #else
  22 #include <div64.h>
  23 #include <linux/compat.h>
  24 #endif
  25
  26 #include <linux/mtd/mtd.h>
  27 #include <linux/mtd/concat.h>
  28
  29 #include <ubi_uboot.h>
  30
  31 /*
  32  * Our storage structure:
  33  * Subdev points to an array of pointers to struct mtd_info objects
  34  * which is allocated along with this structure
  35  *
  36  */
  37 struct mtd_concat {
  38         struct mtd_info mtd;
  39         int num_subdev;
  40         struct mtd_info **subdev;
  41 };
  42
  43 /*
  44  * how to calculate the size required for the above structure,
  45  * including the pointer array subdev points to:
  46  */
  47 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  48         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  49
  50 /*
  51  * Given a pointer to the MTD object in the mtd_concat structure,
  52  * we can retrieve the pointer to that structure with this macro.
  53  */
  54 #define CONCAT(x)  ((struct mtd_concat *)(x))
  55
  56 /*
  57  * MTD methods which look up the relevant subdevice, translate the
  58  * effective address and pass through to the subdevice.
  59  */
  60
  61 static int
  62 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  63             size_t * retlen, u_char * buf)
  64 {
  65         struct mtd_concat *concat = CONCAT(mtd);
  66         int ret = 0, err;
  67         int i;
  68
  69 #ifdef __UBOOT__
  70         *retlen = 0;
  71 #endif
  72
  73         for (i = 0; i < concat->num_subdev; i++) {
  74                 struct mtd_info *subdev = concat->subdev[i];
  75                 size_t size, retsize;
  76
  77                 if (from >= subdev->size) {
  78                         /* Not destined for this subdev */
  79                         size = 0;
  80                         from -= subdev->size;
  81                         continue;
  82                 }
  83                 if (from + len > subdev->size)
  84                         /* First part goes into this subdev */
  85                         size = subdev->size - from;
  86                 else
  87                         /* Entire transaction goes into this subdev */
  88                         size = len;
  89
  90                 err = mtd_read(subdev, from, size, &retsize, buf);
  91
  92                 /* Save information about bitflips! */
  93                 if (unlikely(err)) {
  94                         if (mtd_is_eccerr(err)) {
  95                                 mtd->ecc_stats.failed++;
  96                                 ret = err;
  97                         } else if (mtd_is_bitflip(err)) {
  98                                 mtd->ecc_stats.corrected++;
  99                                 /* Do not overwrite -EBADMSG !! */
 100                                 if (!ret)
 101                                         ret = err;
 102                         } else
 103                                 return err;
 104                 }
 105
 106                 *retlen += retsize;
 107                 len -= size;
 108                 if (len == 0)
 109                         return ret;
 110
 111                 buf += size;
 112                 from = 0;
 113         }
 114         return -EINVAL;
 115 }
 116
 117 static int
 118 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 119              size_t * retlen, const u_char * buf)
 120 {
 121         struct mtd_concat *concat = CONCAT(mtd);
 122         int err = -EINVAL;
 123         int i;
 124
 125 #ifdef __UBOOT__
 126         *retlen = 0;
 127 #endif
 128
 129         for (i = 0; i < concat->num_subdev; i++) {
 130                 struct mtd_info *subdev = concat->subdev[i];
 131                 size_t size, retsize;
 132
 133                 if (to >= subdev->size) {
 134                         size = 0;
 135                         to -= subdev->size;
 136                         continue;
 137                 }
 138                 if (to + len > subdev->size)
 139                         size = subdev->size - to;
 140                 else
 141                         size = len;
 142
 143                 err = mtd_write(subdev, to, size, &retsize, buf);
 144                 if (err)
 145                         break;
 146
 147                 *retlen += retsize;
 148                 len -= size;
 149                 if (len == 0)
 150                         break;
 151
 152                 err = -EINVAL;
 153                 buf += size;
 154                 to = 0;
 155         }
 156         return err;
 157 }
 158
 159 #ifndef __UBOOT__
 160 static int
 161 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 162                 unsigned long count, loff_t to, size_t * retlen)
 163 {
 164         struct mtd_concat *concat = CONCAT(mtd);
 165         struct kvec *vecs_copy;
 166         unsigned long entry_low, entry_high;
 167         size_t total_len = 0;
 168         int i;
 169         int err = -EINVAL;
 170
 171         /* Calculate total length of data */
 172         for (i = 0; i < count; i++)
 173                 total_len += vecs[i].iov_len;
 174
 175         /* Check alignment */
 176         if (mtd->writesize > 1) {
 177                 uint64_t __to = to;
 178                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 179                         return -EINVAL;
 180         }
 181
 182         /* make a copy of vecs */
 183         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 184         if (!vecs_copy)
 185                 return -ENOMEM;
 186
 187         entry_low = 0;
 188         for (i = 0; i < concat->num_subdev; i++) {
 189                 struct mtd_info *subdev = concat->subdev[i];
 190                 size_t size, wsize, retsize, old_iov_len;
 191
 192                 if (to >= subdev->size) {
 193                         to -= subdev->size;
 194                         continue;
 195                 }
 196
 197                 size = min_t(uint64_t, total_len, subdev->size - to);
 198                 wsize = size; /* store for future use */
 199
 200                 entry_high = entry_low;
 201                 while (entry_high < count) {
 202                         if (size <= vecs_copy[entry_high].iov_len)
 203                                 break;
 204                         size -= vecs_copy[entry_high++].iov_len;
 205                 }
 206
 207                 old_iov_len = vecs_copy[entry_high].iov_len;
 208                 vecs_copy[entry_high].iov_len = size;
 209
 210                 err = mtd_writev(subdev, &vecs_copy[entry_low],
 211                                  entry_high - entry_low + 1, to, &retsize);
 212
 213                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 214                 vecs_copy[entry_high].iov_base += size;
 215
 216                 entry_low = entry_high;
 217
 218                 if (err)
 219                         break;
 220
 221                 *retlen += retsize;
 222                 total_len -= wsize;
 223
 224                 if (total_len == 0)
 225                         break;
 226
 227                 err = -EINVAL;
 228                 to = 0;
 229         }
 230
 231         kfree(vecs_copy);
 232         return err;
 233 }
 234 #endif
 235
 236 static int
 237 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 238 {
 239         struct mtd_concat *concat = CONCAT(mtd);
 240         struct mtd_oob_ops devops = *ops;
 241         int i, err, ret = 0;
 242
 243         ops->retlen = ops->oobretlen = 0;
 244
 245         for (i = 0; i < concat->num_subdev; i++) {
 246                 struct mtd_info *subdev = concat->subdev[i];
 247
 248                 if (from >= subdev->size) {
 249                         from -= subdev->size;
 250                         continue;
 251                 }
 252
 253                 /* partial read ? */
 254                 if (from + devops.len > subdev->size)
 255                         devops.len = subdev->size - from;
 256
 257                 err = mtd_read_oob(subdev, from, &devops);
 258                 ops->retlen += devops.retlen;
 259                 ops->oobretlen += devops.oobretlen;
 260
 261                 /* Save information about bitflips! */
 262                 if (unlikely(err)) {
 263                         if (mtd_is_eccerr(err)) {
 264                                 mtd->ecc_stats.failed++;
 265                                 ret = err;
 266                         } else if (mtd_is_bitflip(err)) {
 267                                 mtd->ecc_stats.corrected++;
 268                                 /* Do not overwrite -EBADMSG !! */
 269                                 if (!ret)
 270                                         ret = err;
 271                         } else
 272                                 return err;
 273                 }
 274
 275                 if (devops.datbuf) {
 276                         devops.len = ops->len - ops->retlen;
 277                         if (!devops.len)
 278                                 return ret;
 279                         devops.datbuf += devops.retlen;
 280                 }
 281                 if (devops.oobbuf) {
 282                         devops.ooblen = ops->ooblen - ops->oobretlen;
 283                         if (!devops.ooblen)
 284                                 return ret;
 285                         devops.oobbuf += ops->oobretlen;
 286                 }
 287
 288                 from = 0;
 289         }
 290         return -EINVAL;
 291 }
 292
 293 static int
 294 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 295 {
 296         struct mtd_concat *concat = CONCAT(mtd);
 297         struct mtd_oob_ops devops = *ops;
 298         int i, err;
 299
 300         if (!(mtd->flags & MTD_WRITEABLE))
 301                 return -EROFS;
 302
 303         ops->retlen = ops->oobretlen = 0;
 304
 305         for (i = 0; i < concat->num_subdev; i++) {
 306                 struct mtd_info *subdev = concat->subdev[i];
 307
 308                 if (to >= subdev->size) {
 309                         to -= subdev->size;
 310                         continue;
 311                 }
 312
 313                 /* partial write ? */
 314                 if (to + devops.len > subdev->size)
 315                         devops.len = subdev->size - to;
 316
 317                 err = mtd_write_oob(subdev, to, &devops);
 318                 ops->retlen += devops.oobretlen;
 319                 if (err)
 320                         return err;
 321
 322                 if (devops.datbuf) {
 323                         devops.len = ops->len - ops->retlen;
 324                         if (!devops.len)
 325                                 return 0;
 326                         devops.datbuf += devops.retlen;
 327                 }
 328                 if (devops.oobbuf) {
 329                         devops.ooblen = ops->ooblen - ops->oobretlen;
 330                         if (!devops.ooblen)
 331                                 return 0;
 332                         devops.oobbuf += devops.oobretlen;
 333                 }
 334                 to = 0;
 335         }
 336         return -EINVAL;
 337 }
 338
 339 static void concat_erase_callback(struct erase_info *instr)
 340 {
 341         /* Nothing to do here in U-Boot */
 342 #ifndef __UBOOT__
 343         wake_up((wait_queue_head_t *) instr->priv);
 344 #endif
 345 }
 346
 347 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 348 {
 349         int err;
 350         wait_queue_head_t waitq;
 351         DECLARE_WAITQUEUE(wait, current);
 352
 353         /*
 354          * This code was stol^H^H^H^Hinspired by mtdchar.c
 355          */
 356         init_waitqueue_head(&waitq);
 357
 358         erase->mtd = mtd;
 359         erase->callback = concat_erase_callback;
 360         erase->priv = (unsigned long) &waitq;
 361
 362         /*
 363          * FIXME: Allow INTERRUPTIBLE. Which means
 364          * not having the wait_queue head on the stack.
 365          */
 366         err = mtd_erase(mtd, erase);
 367         if (!err) {
 368                 set_current_state(TASK_UNINTERRUPTIBLE);
 369                 add_wait_queue(&waitq, &wait);
 370                 if (erase->state != MTD_ERASE_DONE
 371                     && erase->state != MTD_ERASE_FAILED)
 372                         schedule();
 373                 remove_wait_queue(&waitq, &wait);
 374                 set_current_state(TASK_RUNNING);
 375
 376                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 377         }
 378         return err;
 379 }
 380
 381 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 382 {
 383         struct mtd_concat *concat = CONCAT(mtd);
 384         struct mtd_info *subdev;
 385         int i, err;
 386         uint64_t length, offset = 0;
 387         struct erase_info *erase;
 388
 389         /*
 390          * Check for proper erase block alignment of the to-be-erased area.
 391          * It is easier to do this based on the super device's erase
 392          * region info rather than looking at each particular sub-device
 393          * in turn.
 394          */
 395         if (!concat->mtd.numeraseregions) {
 396                 /* the easy case: device has uniform erase block size */
 397                 if (instr->addr & (concat->mtd.erasesize - 1))
 398                         return -EINVAL;
 399                 if (instr->len & (concat->mtd.erasesize - 1))
 400                         return -EINVAL;
 401         } else {
 402                 /* device has variable erase size */
 403                 struct mtd_erase_region_info *erase_regions =
 404                     concat->mtd.eraseregions;
 405
 406                 /*
 407                  * Find the erase region where the to-be-erased area begins:
 408                  */
 409                 for (i = 0; i < concat->mtd.numeraseregions &&
 410                      instr->addr >= erase_regions[i].offset; i++) ;
 411                 --i;
 412
 413                 /*
 414                  * Now erase_regions[i] is the region in which the
 415                  * to-be-erased area begins. Verify that the starting
 416                  * offset is aligned to this region's erase size:
 417                  */
 418                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 419                         return -EINVAL;
 420
 421                 /*
 422                  * now find the erase region where the to-be-erased area ends:
 423                  */
 424                 for (; i < concat->mtd.numeraseregions &&
 425                      (instr->addr + instr->len) >= erase_regions[i].offset;
 426                      ++i) ;
 427                 --i;
 428                 /*
 429                  * check if the ending offset is aligned to this region's erase size
 430                  */
 431                 if (i < 0 || ((instr->addr + instr->len) &
 432                                         (erase_regions[i].erasesize - 1)))
 433                         return -EINVAL;
 434         }
 435
 436         /* make a local copy of instr to avoid modifying the caller's struct */
 437         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 438
 439         if (!erase)
 440                 return -ENOMEM;
 441
 442         *erase = *instr;
 443         length = instr->len;
 444
 445         /*
 446          * find the subdevice where the to-be-erased area begins, adjust
 447          * starting offset to be relative to the subdevice start
 448          */
 449         for (i = 0; i < concat->num_subdev; i++) {
 450                 subdev = concat->subdev[i];
 451                 if (subdev->size <= erase->addr) {
 452                         erase->addr -= subdev->size;
 453                         offset += subdev->size;
 454                 } else {
 455                         break;
 456                 }
 457         }
 458
 459         /* must never happen since size limit has been verified above */
 460         BUG_ON(i >= concat->num_subdev);
 461
 462         /* now do the erase: */
 463         err = 0;
 464         for (; length > 0; i++) {
 465                 /* loop for all subdevices affected by this request */
 466                 subdev = concat->subdev[i];     /* get current subdevice */
 467
 468                 /* limit length to subdevice's size: */
 469                 if (erase->addr + length > subdev->size)
 470                         erase->len = subdev->size - erase->addr;
 471                 else
 472                         erase->len = length;
 473
 474                 length -= erase->len;
 475                 if ((err = concat_dev_erase(subdev, erase))) {
 476                         /* sanity check: should never happen since
 477                          * block alignment has been checked above */
 478                         BUG_ON(err == -EINVAL);
 479                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 480                                 instr->fail_addr = erase->fail_addr + offset;
 481                         break;
 482                 }
 483                 /*
 484                  * erase->addr specifies the offset of the area to be
 485                  * erased *within the current subdevice*. It can be
 486                  * non-zero only the first time through this loop, i.e.
 487                  * for the first subdevice where blocks need to be erased.
 488                  * All the following erases must begin at the start of the
 489                  * current subdevice, i.e. at offset zero.
 490                  */
 491                 erase->addr = 0;
 492                 offset += subdev->size;
 493         }
 494         instr->state = erase->state;
 495         kfree(erase);
 496         if (err)
 497                 return err;
 498
 499         if (instr->callback)
 500                 instr->callback(instr);
 501         return 0;
 502 }
 503
 504 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 505 {
 506         struct mtd_concat *concat = CONCAT(mtd);
 507         int i, err = -EINVAL;
 508
 509         for (i = 0; i < concat->num_subdev; i++) {
 510                 struct mtd_info *subdev = concat->subdev[i];
 511                 uint64_t size;
 512
 513                 if (ofs >= subdev->size) {
 514                         size = 0;
 515                         ofs -= subdev->size;
 516                         continue;
 517                 }
 518                 if (ofs + len > subdev->size)
 519                         size = subdev->size - ofs;
 520                 else
 521                         size = len;
 522
 523                 err = mtd_lock(subdev, ofs, size);
 524                 if (err)
 525                         break;
 526
 527                 len -= size;
 528                 if (len == 0)
 529                         break;
 530
 531                 err = -EINVAL;
 532                 ofs = 0;
 533         }
 534
 535         return err;
 536 }
 537
 538 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 539 {
 540         struct mtd_concat *concat = CONCAT(mtd);
 541         int i, err = 0;
 542
 543         for (i = 0; i < concat->num_subdev; i++) {
 544                 struct mtd_info *subdev = concat->subdev[i];
 545                 uint64_t size;
 546
 547                 if (ofs >= subdev->size) {
 548                         size = 0;
 549                         ofs -= subdev->size;
 550                         continue;
 551                 }
 552                 if (ofs + len > subdev->size)
 553                         size = subdev->size - ofs;
 554                 else
 555                         size = len;
 556
 557                 err = mtd_unlock(subdev, ofs, size);
 558                 if (err)
 559                         break;
 560
 561                 len -= size;
 562                 if (len == 0)
 563                         break;
 564
 565                 err = -EINVAL;
 566                 ofs = 0;
 567         }
 568
 569         return err;
 570 }
 571
 572 static void concat_sync(struct mtd_info *mtd)
 573 {
 574         struct mtd_concat *concat = CONCAT(mtd);
 575         int i;
 576
 577         for (i = 0; i < concat->num_subdev; i++) {
 578                 struct mtd_info *subdev = concat->subdev[i];
 579                 mtd_sync(subdev);
 580         }
 581 }
 582
 583 #ifndef __UBOOT__
 584 static int concat_suspend(struct mtd_info *mtd)
 585 {
 586         struct mtd_concat *concat = CONCAT(mtd);
 587         int i, rc = 0;
 588
 589         for (i = 0; i < concat->num_subdev; i++) {
 590                 struct mtd_info *subdev = concat->subdev[i];
 591                 if ((rc = mtd_suspend(subdev)) < 0)
 592                         return rc;
 593         }
 594         return rc;
 595 }
 596
 597 static void concat_resume(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                 mtd_resume(subdev);
 605         }
 606 }
 607 #endif
 608
 609 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 610 {
 611         struct mtd_concat *concat = CONCAT(mtd);
 612         int i, res = 0;
 613
 614         if (!mtd_can_have_bb(concat->subdev[0]))
 615                 return res;
 616
 617         for (i = 0; i < concat->num_subdev; i++) {
 618                 struct mtd_info *subdev = concat->subdev[i];
 619
 620                 if (ofs >= subdev->size) {
 621                         ofs -= subdev->size;
 622                         continue;
 623                 }
 624
 625                 res = mtd_block_isbad(subdev, ofs);
 626                 break;
 627         }
 628
 629         return res;
 630 }
 631
 632 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 633 {
 634         struct mtd_concat *concat = CONCAT(mtd);
 635         int i, err = -EINVAL;
 636
 637         for (i = 0; i < concat->num_subdev; i++) {
 638                 struct mtd_info *subdev = concat->subdev[i];
 639
 640                 if (ofs >= subdev->size) {
 641                         ofs -= subdev->size;
 642                         continue;
 643                 }
 644
 645                 err = mtd_block_markbad(subdev, ofs);
 646                 if (!err)
 647                         mtd->ecc_stats.badblocks++;
 648                 break;
 649         }
 650
 651         return err;
 652 }
 653
 654 /*
 655  * try to support NOMMU mmaps on concatenated devices
 656  * - we don't support subdev spanning as we can't guarantee it'll work
 657  */
 658 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 659                                               unsigned long len,
 660                                               unsigned long offset,
 661                                               unsigned long flags)
 662 {
 663         struct mtd_concat *concat = CONCAT(mtd);
 664         int i;
 665
 666         for (i = 0; i < concat->num_subdev; i++) {
 667                 struct mtd_info *subdev = concat->subdev[i];
 668
 669                 if (offset >= subdev->size) {
 670                         offset -= subdev->size;
 671                         continue;
 672                 }
 673
 674                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 675         }
 676
 677         return (unsigned long) -ENOSYS;
 678 }
 679
 680 /*
 681  * This function constructs a virtual MTD device by concatenating
 682  * num_devs MTD devices. A pointer to the new device object is
 683  * stored to *new_dev upon success. This function does _not_
 684  * register any devices: this is the caller's responsibility.
 685  */
 686 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 687                                    int num_devs,        /* number of subdevices      */
 688 #ifndef __UBOOT__
 689                                    const char *name)
 690 #else
 691                                    char *name)
 692 #endif
 693 {                               /* name for the new device   */
 694         int i;
 695         size_t size;
 696         struct mtd_concat *concat;
 697         uint32_t max_erasesize, curr_erasesize;
 698         int num_erase_region;
 699         int max_writebufsize = 0;
 700
 701         debug("Concatenating MTD devices:\n");
 702         for (i = 0; i < num_devs; i++)
 703                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 704         debug("into device \"%s\"\n", name);
 705
 706         /* allocate the device structure */
 707         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 708         concat = kzalloc(size, GFP_KERNEL);
 709         if (!concat) {
 710                 printk
 711                     ("memory allocation error while creating concatenated device \"%s\"\n",
 712                      name);
 713                 return NULL;
 714         }
 715         concat->subdev = (struct mtd_info **) (concat + 1);
 716
 717         /*
 718          * Set up the new "super" device's MTD object structure, check for
 719          * incompatibilities between the subdevices.
 720          */
 721         concat->mtd.type = subdev[0]->type;
 722         concat->mtd.flags = subdev[0]->flags;
 723         concat->mtd.size = subdev[0]->size;
 724         concat->mtd.erasesize = subdev[0]->erasesize;
 725         concat->mtd.writesize = subdev[0]->writesize;
 726
 727         for (i = 0; i < num_devs; i++)
 728                 if (max_writebufsize < subdev[i]->writebufsize)
 729                         max_writebufsize = subdev[i]->writebufsize;
 730         concat->mtd.writebufsize = max_writebufsize;
 731
 732         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 733         concat->mtd.oobsize = subdev[0]->oobsize;
 734         concat->mtd.oobavail = subdev[0]->oobavail;
 735 #ifndef __UBOOT__
 736         if (subdev[0]->_writev)
 737                 concat->mtd._writev = concat_writev;
 738 #endif
 739         if (subdev[0]->_read_oob)
 740                 concat->mtd._read_oob = concat_read_oob;
 741         if (subdev[0]->_write_oob)
 742                 concat->mtd._write_oob = concat_write_oob;
 743         if (subdev[0]->_block_isbad)
 744                 concat->mtd._block_isbad = concat_block_isbad;
 745         if (subdev[0]->_block_markbad)
 746                 concat->mtd._block_markbad = concat_block_markbad;
 747
 748         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 749
 750 #ifndef __UBOOT__
 751         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 752 #endif
 753
 754         concat->subdev[0] = subdev[0];
 755
 756         for (i = 1; i < num_devs; i++) {
 757                 if (concat->mtd.type != subdev[i]->type) {
 758                         kfree(concat);
 759                         printk("Incompatible device type on \"%s\"\n",
 760                                subdev[i]->name);
 761                         return NULL;
 762                 }
 763                 if (concat->mtd.flags != subdev[i]->flags) {
 764                         /*
 765                          * Expect all flags except MTD_WRITEABLE to be
 766                          * equal on all subdevices.
 767                          */
 768                         if ((concat->mtd.flags ^ subdev[i]->
 769                              flags) & ~MTD_WRITEABLE) {
 770                                 kfree(concat);
 771                                 printk("Incompatible device flags on \"%s\"\n",
 772                                        subdev[i]->name);
 773                                 return NULL;
 774                         } else
 775                                 /* if writeable attribute differs,
 776                                    make super device writeable */
 777                                 concat->mtd.flags |=
 778                                     subdev[i]->flags & MTD_WRITEABLE;
 779                 }
 780
 781 #ifndef __UBOOT__
 782                 /* only permit direct mapping if the BDIs are all the same
 783                  * - copy-mapping is still permitted
 784                  */
 785                 if (concat->mtd.backing_dev_info !=
 786                     subdev[i]->backing_dev_info)
 787                         concat->mtd.backing_dev_info =
 788                                 &default_backing_dev_info;
 789 #endif
 790
 791                 concat->mtd.size += subdev[i]->size;
 792                 concat->mtd.ecc_stats.badblocks +=
 793                         subdev[i]->ecc_stats.badblocks;
 794                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 795                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 796                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 797                     !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
 798                     !concat->mtd._write_oob != !subdev[i]->_write_oob) {
 799                         kfree(concat);
 800                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 801                                subdev[i]->name);
 802                         return NULL;
 803                 }
 804                 concat->subdev[i] = subdev[i];
 805
 806         }
 807
 808         concat->mtd.ecclayout = subdev[0]->ecclayout;
 809
 810         concat->num_subdev = num_devs;
 811         concat->mtd.name = name;
 812
 813         concat->mtd._erase = concat_erase;
 814         concat->mtd._read = concat_read;
 815         concat->mtd._write = concat_write;
 816         concat->mtd._sync = concat_sync;
 817         concat->mtd._lock = concat_lock;
 818         concat->mtd._unlock = concat_unlock;
 819 #ifndef __UBOOT__
 820         concat->mtd._suspend = concat_suspend;
 821         concat->mtd._resume = concat_resume;
 822 #endif
 823         concat->mtd._get_unmapped_area = concat_get_unmapped_area;
 824
 825         /*
 826          * Combine the erase block size info of the subdevices:
 827          *
 828          * first, walk the map of the new device and see how
 829          * many changes in erase size we have
 830          */
 831         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 832         num_erase_region = 1;
 833         for (i = 0; i < num_devs; i++) {
 834                 if (subdev[i]->numeraseregions == 0) {
 835                         /* current subdevice has uniform erase size */
 836                         if (subdev[i]->erasesize != curr_erasesize) {
 837                                 /* if it differs from the last subdevice's erase size, count it */
 838                                 ++num_erase_region;
 839                                 curr_erasesize = subdev[i]->erasesize;
 840                                 if (curr_erasesize > max_erasesize)
 841                                         max_erasesize = curr_erasesize;
 842                         }
 843                 } else {
 844                         /* current subdevice has variable erase size */
 845                         int j;
 846                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 847
 848                                 /* walk the list of erase regions, count any changes */
 849                                 if (subdev[i]->eraseregions[j].erasesize !=
 850                                     curr_erasesize) {
 851                                         ++num_erase_region;
 852                                         curr_erasesize =
 853                                             subdev[i]->eraseregions[j].
 854                                             erasesize;
 855                                         if (curr_erasesize > max_erasesize)
 856                                                 max_erasesize = curr_erasesize;
 857                                 }
 858                         }
 859                 }
 860         }
 861
 862         if (num_erase_region == 1) {
 863                 /*
 864                  * All subdevices have the same uniform erase size.
 865                  * This is easy:
 866                  */
 867                 concat->mtd.erasesize = curr_erasesize;
 868                 concat->mtd.numeraseregions = 0;
 869         } else {
 870                 uint64_t tmp64;
 871
 872                 /*
 873                  * erase block size varies across the subdevices: allocate
 874                  * space to store the data describing the variable erase regions
 875                  */
 876                 struct mtd_erase_region_info *erase_region_p;
 877                 uint64_t begin, position;
 878
 879                 concat->mtd.erasesize = max_erasesize;
 880                 concat->mtd.numeraseregions = num_erase_region;
 881                 concat->mtd.eraseregions = erase_region_p =
 882                     kmalloc(num_erase_region *
 883                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 884                 if (!erase_region_p) {
 885                         kfree(concat);
 886                         printk
 887                             ("memory allocation error while creating erase region list"
 888                              " for device \"%s\"\n", name);
 889                         return NULL;
 890                 }
 891
 892                 /*
 893                  * walk the map of the new device once more and fill in
 894                  * in erase region info:
 895                  */
 896                 curr_erasesize = subdev[0]->erasesize;
 897                 begin = position = 0;
 898                 for (i = 0; i < num_devs; i++) {
 899                         if (subdev[i]->numeraseregions == 0) {
 900                                 /* current subdevice has uniform erase size */
 901                                 if (subdev[i]->erasesize != curr_erasesize) {
 902                                         /*
 903                                          *  fill in an mtd_erase_region_info structure for the area
 904                                          *  we have walked so far:
 905                                          */
 906                                         erase_region_p->offset = begin;
 907                                         erase_region_p->erasesize =
 908                                             curr_erasesize;
 909                                         tmp64 = position - begin;
 910                                         do_div(tmp64, curr_erasesize);
 911                                         erase_region_p->numblocks = tmp64;
 912                                         begin = position;
 913
 914                                         curr_erasesize = subdev[i]->erasesize;
 915                                         ++erase_region_p;
 916                                 }
 917                                 position += subdev[i]->size;
 918                         } else {
 919                                 /* current subdevice has variable erase size */
 920                                 int j;
 921                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 922                                         /* walk the list of erase regions, count any changes */
 923                                         if (subdev[i]->eraseregions[j].
 924                                             erasesize != curr_erasesize) {
 925                                                 erase_region_p->offset = begin;
 926                                                 erase_region_p->erasesize =
 927                                                     curr_erasesize;
 928                                                 tmp64 = position - begin;
 929                                                 do_div(tmp64, curr_erasesize);
 930                                                 erase_region_p->numblocks = tmp64;
 931                                                 begin = position;
 932
 933                                                 curr_erasesize =
 934                                                     subdev[i]->eraseregions[j].
 935                                                     erasesize;
 936                                                 ++erase_region_p;
 937                                         }
 938                                         position +=
 939                                             subdev[i]->eraseregions[j].
 940                                             numblocks * (uint64_t)curr_erasesize;
 941                                 }
 942                         }
 943                 }
 944                 /* Now write the final entry */
 945                 erase_region_p->offset = begin;
 946                 erase_region_p->erasesize = curr_erasesize;
 947                 tmp64 = position - begin;
 948                 do_div(tmp64, curr_erasesize);
 949                 erase_region_p->numblocks = tmp64;
 950         }
 951
 952         return &concat->mtd;
 953 }
 954
 955 /*
 956  * This function destroys an MTD object obtained from concat_mtd_devs()
 957  */
 958
 959 void mtd_concat_destroy(struct mtd_info *mtd)
 960 {
 961         struct mtd_concat *concat = CONCAT(mtd);
 962         if (concat->mtd.numeraseregions)
 963                 kfree(concat->mtd.eraseregions);
 964         kfree(concat);
 965 }
 966
 967 EXPORT_SYMBOL(mtd_concat_create);
 968 EXPORT_SYMBOL(mtd_concat_destroy);
 969
 970 MODULE_LICENSE("GPL");
 971 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 972 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");