drivers/mtd/mtdconcat.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * MTD device concatenation layer
   4  *
   5  * Copyright © 2002 Robert Kaiser <rkaiser@sysgo.de>
   6  * Copyright © 2002-2010 David Woodhouse <dwmw2@infradead.org>
   7  *
   8  * NAND support by Christian Gan <cgan@iders.ca>
   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 #include <linux/backing-dev.h>
  17
  18 #include <linux/mtd/mtd.h>
  19 #include <linux/mtd/concat.h>
  20
  21 #include <asm/div64.h>
  22
  23 /*
  24  * Our storage structure:
  25  * Subdev points to an array of pointers to struct mtd_info objects
  26  * which is allocated along with this structure
  27  *
  28  */
  29 struct mtd_concat {
  30         struct mtd_info mtd;
  31         int num_subdev;
  32         struct mtd_info **subdev;
  33 };
  34
  35 /*
  36  * how to calculate the size required for the above structure,
  37  * including the pointer array subdev points to:
  38  */
  39 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  40         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  41
  42 /*
  43  * Given a pointer to the MTD object in the mtd_concat structure,
  44  * we can retrieve the pointer to that structure with this macro.
  45  */
  46 #define CONCAT(x)  ((struct mtd_concat *)(x))
  47
  48 /*
  49  * MTD methods which look up the relevant subdevice, translate the
  50  * effective address and pass through to the subdevice.
  51  */
  52
  53 static int
  54 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  55             size_t * retlen, u_char * buf)
  56 {
  57         struct mtd_concat *concat = CONCAT(mtd);
  58         int ret = 0, err;
  59         int i;
  60
  61         for (i = 0; i < concat->num_subdev; i++) {
  62                 struct mtd_info *subdev = concat->subdev[i];
  63                 size_t size, retsize;
  64
  65                 if (from >= subdev->size) {
  66                         /* Not destined for this subdev */
  67                         size = 0;
  68                         from -= subdev->size;
  69                         continue;
  70                 }
  71                 if (from + len > subdev->size)
  72                         /* First part goes into this subdev */
  73                         size = subdev->size - from;
  74                 else
  75                         /* Entire transaction goes into this subdev */
  76                         size = len;
  77
  78                 err = mtd_read(subdev, from, size, &retsize, buf);
  79
  80                 /* Save information about bitflips! */
  81                 if (unlikely(err)) {
  82                         if (mtd_is_eccerr(err)) {
  83                                 mtd->ecc_stats.failed++;
  84                                 ret = err;
  85                         } else if (mtd_is_bitflip(err)) {
  86                                 mtd->ecc_stats.corrected++;
  87                                 /* Do not overwrite -EBADMSG !! */
  88                                 if (!ret)
  89                                         ret = err;
  90                         } else
  91                                 return err;
  92                 }
  93
  94                 *retlen += retsize;
  95                 len -= size;
  96                 if (len == 0)
  97                         return ret;
  98
  99                 buf += size;
 100                 from = 0;
 101         }
 102         return -EINVAL;
 103 }
 104
 105 static int
 106 concat_panic_write(struct mtd_info *mtd, loff_t to, size_t len,
 107              size_t * retlen, const u_char * buf)
 108 {
 109         struct mtd_concat *concat = CONCAT(mtd);
 110         int err = -EINVAL;
 111         int i;
 112         for (i = 0; i < concat->num_subdev; i++) {
 113                 struct mtd_info *subdev = concat->subdev[i];
 114                 size_t size, retsize;
 115
 116                 if (to >= subdev->size) {
 117                         to -= subdev->size;
 118                         continue;
 119                 }
 120                 if (to + len > subdev->size)
 121                         size = subdev->size - to;
 122                 else
 123                         size = len;
 124
 125                 err = mtd_panic_write(subdev, to, size, &retsize, buf);
 126                 if (err == -EOPNOTSUPP) {
 127                         printk(KERN_ERR "mtdconcat: Cannot write from panic without panic_write\n");
 128                         return err;
 129                 }
 130                 if (err)
 131                         break;
 132
 133                 *retlen += retsize;
 134                 len -= size;
 135                 if (len == 0)
 136                         break;
 137
 138                 err = -EINVAL;
 139                 buf += size;
 140                 to = 0;
 141         }
 142         return err;
 143 }
 144
 145
 146 static int
 147 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 148              size_t * retlen, const u_char * buf)
 149 {
 150         struct mtd_concat *concat = CONCAT(mtd);
 151         int err = -EINVAL;
 152         int i;
 153
 154         for (i = 0; i < concat->num_subdev; i++) {
 155                 struct mtd_info *subdev = concat->subdev[i];
 156                 size_t size, retsize;
 157
 158                 if (to >= subdev->size) {
 159                         size = 0;
 160                         to -= subdev->size;
 161                         continue;
 162                 }
 163                 if (to + len > subdev->size)
 164                         size = subdev->size - to;
 165                 else
 166                         size = len;
 167
 168                 err = mtd_write(subdev, to, size, &retsize, buf);
 169                 if (err)
 170                         break;
 171
 172                 *retlen += retsize;
 173                 len -= size;
 174                 if (len == 0)
 175                         break;
 176
 177                 err = -EINVAL;
 178                 buf += size;
 179                 to = 0;
 180         }
 181         return err;
 182 }
 183
 184 static int
 185 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 186                 unsigned long count, loff_t to, size_t * retlen)
 187 {
 188         struct mtd_concat *concat = CONCAT(mtd);
 189         struct kvec *vecs_copy;
 190         unsigned long entry_low, entry_high;
 191         size_t total_len = 0;
 192         int i;
 193         int err = -EINVAL;
 194
 195         /* Calculate total length of data */
 196         for (i = 0; i < count; i++)
 197                 total_len += vecs[i].iov_len;
 198
 199         /* Check alignment */
 200         if (mtd->writesize > 1) {
 201                 uint64_t __to = to;
 202                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 203                         return -EINVAL;
 204         }
 205
 206         /* make a copy of vecs */
 207         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 208         if (!vecs_copy)
 209                 return -ENOMEM;
 210
 211         entry_low = 0;
 212         for (i = 0; i < concat->num_subdev; i++) {
 213                 struct mtd_info *subdev = concat->subdev[i];
 214                 size_t size, wsize, retsize, old_iov_len;
 215
 216                 if (to >= subdev->size) {
 217                         to -= subdev->size;
 218                         continue;
 219                 }
 220
 221                 size = min_t(uint64_t, total_len, subdev->size - to);
 222                 wsize = size; /* store for future use */
 223
 224                 entry_high = entry_low;
 225                 while (entry_high < count) {
 226                         if (size <= vecs_copy[entry_high].iov_len)
 227                                 break;
 228                         size -= vecs_copy[entry_high++].iov_len;
 229                 }
 230
 231                 old_iov_len = vecs_copy[entry_high].iov_len;
 232                 vecs_copy[entry_high].iov_len = size;
 233
 234                 err = mtd_writev(subdev, &vecs_copy[entry_low],
 235                                  entry_high - entry_low + 1, to, &retsize);
 236
 237                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 238                 vecs_copy[entry_high].iov_base += size;
 239
 240                 entry_low = entry_high;
 241
 242                 if (err)
 243                         break;
 244
 245                 *retlen += retsize;
 246                 total_len -= wsize;
 247
 248                 if (total_len == 0)
 249                         break;
 250
 251                 err = -EINVAL;
 252                 to = 0;
 253         }
 254
 255         kfree(vecs_copy);
 256         return err;
 257 }
 258
 259 static int
 260 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 261 {
 262         struct mtd_concat *concat = CONCAT(mtd);
 263         struct mtd_oob_ops devops = *ops;
 264         int i, err, ret = 0;
 265
 266         ops->retlen = ops->oobretlen = 0;
 267
 268         for (i = 0; i < concat->num_subdev; i++) {
 269                 struct mtd_info *subdev = concat->subdev[i];
 270
 271                 if (from >= subdev->size) {
 272                         from -= subdev->size;
 273                         continue;
 274                 }
 275
 276                 /* partial read ? */
 277                 if (from + devops.len > subdev->size)
 278                         devops.len = subdev->size - from;
 279
 280                 err = mtd_read_oob(subdev, from, &devops);
 281                 ops->retlen += devops.retlen;
 282                 ops->oobretlen += devops.oobretlen;
 283
 284                 /* Save information about bitflips! */
 285                 if (unlikely(err)) {
 286                         if (mtd_is_eccerr(err)) {
 287                                 mtd->ecc_stats.failed++;
 288                                 ret = err;
 289                         } else if (mtd_is_bitflip(err)) {
 290                                 mtd->ecc_stats.corrected++;
 291                                 /* Do not overwrite -EBADMSG !! */
 292                                 if (!ret)
 293                                         ret = err;
 294                         } else
 295                                 return err;
 296                 }
 297
 298                 if (devops.datbuf) {
 299                         devops.len = ops->len - ops->retlen;
 300                         if (!devops.len)
 301                                 return ret;
 302                         devops.datbuf += devops.retlen;
 303                 }
 304                 if (devops.oobbuf) {
 305                         devops.ooblen = ops->ooblen - ops->oobretlen;
 306                         if (!devops.ooblen)
 307                                 return ret;
 308                         devops.oobbuf += ops->oobretlen;
 309                 }
 310
 311                 from = 0;
 312         }
 313         return -EINVAL;
 314 }
 315
 316 static int
 317 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 318 {
 319         struct mtd_concat *concat = CONCAT(mtd);
 320         struct mtd_oob_ops devops = *ops;
 321         int i, err;
 322
 323         if (!(mtd->flags & MTD_WRITEABLE))
 324                 return -EROFS;
 325
 326         ops->retlen = ops->oobretlen = 0;
 327
 328         for (i = 0; i < concat->num_subdev; i++) {
 329                 struct mtd_info *subdev = concat->subdev[i];
 330
 331                 if (to >= subdev->size) {
 332                         to -= subdev->size;
 333                         continue;
 334                 }
 335
 336                 /* partial write ? */
 337                 if (to + devops.len > subdev->size)
 338                         devops.len = subdev->size - to;
 339
 340                 err = mtd_write_oob(subdev, to, &devops);
 341                 ops->retlen += devops.retlen;
 342                 ops->oobretlen += devops.oobretlen;
 343                 if (err)
 344                         return err;
 345
 346                 if (devops.datbuf) {
 347                         devops.len = ops->len - ops->retlen;
 348                         if (!devops.len)
 349                                 return 0;
 350                         devops.datbuf += devops.retlen;
 351                 }
 352                 if (devops.oobbuf) {
 353                         devops.ooblen = ops->ooblen - ops->oobretlen;
 354                         if (!devops.ooblen)
 355                                 return 0;
 356                         devops.oobbuf += devops.oobretlen;
 357                 }
 358                 to = 0;
 359         }
 360         return -EINVAL;
 361 }
 362
 363 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 364 {
 365         struct mtd_concat *concat = CONCAT(mtd);
 366         struct mtd_info *subdev;
 367         int i, err;
 368         uint64_t length, offset = 0;
 369         struct erase_info *erase;
 370
 371         /*
 372          * Check for proper erase block alignment of the to-be-erased area.
 373          * It is easier to do this based on the super device's erase
 374          * region info rather than looking at each particular sub-device
 375          * in turn.
 376          */
 377         if (!concat->mtd.numeraseregions) {
 378                 /* the easy case: device has uniform erase block size */
 379                 if (instr->addr & (concat->mtd.erasesize - 1))
 380                         return -EINVAL;
 381                 if (instr->len & (concat->mtd.erasesize - 1))
 382                         return -EINVAL;
 383         } else {
 384                 /* device has variable erase size */
 385                 struct mtd_erase_region_info *erase_regions =
 386                     concat->mtd.eraseregions;
 387
 388                 /*
 389                  * Find the erase region where the to-be-erased area begins:
 390                  */
 391                 for (i = 0; i < concat->mtd.numeraseregions &&
 392                      instr->addr >= erase_regions[i].offset; i++) ;
 393                 --i;
 394
 395                 /*
 396                  * Now erase_regions[i] is the region in which the
 397                  * to-be-erased area begins. Verify that the starting
 398                  * offset is aligned to this region's erase size:
 399                  */
 400                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 401                         return -EINVAL;
 402
 403                 /*
 404                  * now find the erase region where the to-be-erased area ends:
 405                  */
 406                 for (; i < concat->mtd.numeraseregions &&
 407                      (instr->addr + instr->len) >= erase_regions[i].offset;
 408                      ++i) ;
 409                 --i;
 410                 /*
 411                  * check if the ending offset is aligned to this region's erase size
 412                  */
 413                 if (i < 0 || ((instr->addr + instr->len) &
 414                                         (erase_regions[i].erasesize - 1)))
 415                         return -EINVAL;
 416         }
 417
 418         /* make a local copy of instr to avoid modifying the caller's struct */
 419         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 420
 421         if (!erase)
 422                 return -ENOMEM;
 423
 424         *erase = *instr;
 425         length = instr->len;
 426
 427         /*
 428          * find the subdevice where the to-be-erased area begins, adjust
 429          * starting offset to be relative to the subdevice start
 430          */
 431         for (i = 0; i < concat->num_subdev; i++) {
 432                 subdev = concat->subdev[i];
 433                 if (subdev->size <= erase->addr) {
 434                         erase->addr -= subdev->size;
 435                         offset += subdev->size;
 436                 } else {
 437                         break;
 438                 }
 439         }
 440
 441         /* must never happen since size limit has been verified above */
 442         BUG_ON(i >= concat->num_subdev);
 443
 444         /* now do the erase: */
 445         err = 0;
 446         for (; length > 0; i++) {
 447                 /* loop for all subdevices affected by this request */
 448                 subdev = concat->subdev[i];     /* get current subdevice */
 449
 450                 /* limit length to subdevice's size: */
 451                 if (erase->addr + length > subdev->size)
 452                         erase->len = subdev->size - erase->addr;
 453                 else
 454                         erase->len = length;
 455
 456                 length -= erase->len;
 457                 if ((err = mtd_erase(subdev, erase))) {
 458                         /* sanity check: should never happen since
 459                          * block alignment has been checked above */
 460                         BUG_ON(err == -EINVAL);
 461                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 462                                 instr->fail_addr = erase->fail_addr + offset;
 463                         break;
 464                 }
 465                 /*
 466                  * erase->addr specifies the offset of the area to be
 467                  * erased *within the current subdevice*. It can be
 468                  * non-zero only the first time through this loop, i.e.
 469                  * for the first subdevice where blocks need to be erased.
 470                  * All the following erases must begin at the start of the
 471                  * current subdevice, i.e. at offset zero.
 472                  */
 473                 erase->addr = 0;
 474                 offset += subdev->size;
 475         }
 476         kfree(erase);
 477
 478         return err;
 479 }
 480
 481 static int concat_xxlock(struct mtd_info *mtd, loff_t ofs, uint64_t len,
 482                          bool is_lock)
 483 {
 484         struct mtd_concat *concat = CONCAT(mtd);
 485         int i, err = -EINVAL;
 486
 487         for (i = 0; i < concat->num_subdev; i++) {
 488                 struct mtd_info *subdev = concat->subdev[i];
 489                 uint64_t size;
 490
 491                 if (ofs >= subdev->size) {
 492                         size = 0;
 493                         ofs -= subdev->size;
 494                         continue;
 495                 }
 496                 if (ofs + len > subdev->size)
 497                         size = subdev->size - ofs;
 498                 else
 499                         size = len;
 500
 501                 if (is_lock)
 502                         err = mtd_lock(subdev, ofs, size);
 503                 else
 504                         err = mtd_unlock(subdev, ofs, size);
 505                 if (err)
 506                         break;
 507
 508                 len -= size;
 509                 if (len == 0)
 510                         break;
 511
 512                 err = -EINVAL;
 513                 ofs = 0;
 514         }
 515
 516         return err;
 517 }
 518
 519 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 520 {
 521         return concat_xxlock(mtd, ofs, len, true);
 522 }
 523
 524 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 525 {
 526         return concat_xxlock(mtd, ofs, len, false);
 527 }
 528
 529 static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 530 {
 531         struct mtd_concat *concat = CONCAT(mtd);
 532         int i, err = -EINVAL;
 533
 534         for (i = 0; i < concat->num_subdev; i++) {
 535                 struct mtd_info *subdev = concat->subdev[i];
 536
 537                 if (ofs >= subdev->size) {
 538                         ofs -= subdev->size;
 539                         continue;
 540                 }
 541
 542                 if (ofs + len > subdev->size)
 543                         break;
 544
 545                 return mtd_is_locked(subdev, ofs, len);
 546         }
 547
 548         return err;
 549 }
 550
 551 static void concat_sync(struct mtd_info *mtd)
 552 {
 553         struct mtd_concat *concat = CONCAT(mtd);
 554         int i;
 555
 556         for (i = 0; i < concat->num_subdev; i++) {
 557                 struct mtd_info *subdev = concat->subdev[i];
 558                 mtd_sync(subdev);
 559         }
 560 }
 561
 562 static int concat_suspend(struct mtd_info *mtd)
 563 {
 564         struct mtd_concat *concat = CONCAT(mtd);
 565         int i, rc = 0;
 566
 567         for (i = 0; i < concat->num_subdev; i++) {
 568                 struct mtd_info *subdev = concat->subdev[i];
 569                 if ((rc = mtd_suspend(subdev)) < 0)
 570                         return rc;
 571         }
 572         return rc;
 573 }
 574
 575 static void concat_resume(struct mtd_info *mtd)
 576 {
 577         struct mtd_concat *concat = CONCAT(mtd);
 578         int i;
 579
 580         for (i = 0; i < concat->num_subdev; i++) {
 581                 struct mtd_info *subdev = concat->subdev[i];
 582                 mtd_resume(subdev);
 583         }
 584 }
 585
 586 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 587 {
 588         struct mtd_concat *concat = CONCAT(mtd);
 589         int i, res = 0;
 590
 591         if (!mtd_can_have_bb(concat->subdev[0]))
 592                 return res;
 593
 594         for (i = 0; i < concat->num_subdev; i++) {
 595                 struct mtd_info *subdev = concat->subdev[i];
 596
 597                 if (ofs >= subdev->size) {
 598                         ofs -= subdev->size;
 599                         continue;
 600                 }
 601
 602                 res = mtd_block_isbad(subdev, ofs);
 603                 break;
 604         }
 605
 606         return res;
 607 }
 608
 609 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 610 {
 611         struct mtd_concat *concat = CONCAT(mtd);
 612         int i, err = -EINVAL;
 613
 614         for (i = 0; i < concat->num_subdev; i++) {
 615                 struct mtd_info *subdev = concat->subdev[i];
 616
 617                 if (ofs >= subdev->size) {
 618                         ofs -= subdev->size;
 619                         continue;
 620                 }
 621
 622                 err = mtd_block_markbad(subdev, ofs);
 623                 if (!err)
 624                         mtd->ecc_stats.badblocks++;
 625                 break;
 626         }
 627
 628         return err;
 629 }
 630
 631 /*
 632  * This function constructs a virtual MTD device by concatenating
 633  * num_devs MTD devices. A pointer to the new device object is
 634  * stored to *new_dev upon success. This function does _not_
 635  * register any devices: this is the caller's responsibility.
 636  */
 637 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 638                                    int num_devs,        /* number of subdevices      */
 639                                    const char *name)
 640 {                               /* name for the new device   */
 641         int i;
 642         size_t size;
 643         struct mtd_concat *concat;
 644         struct mtd_info *subdev_master = NULL;
 645         uint32_t max_erasesize, curr_erasesize;
 646         int num_erase_region;
 647         int max_writebufsize = 0;
 648
 649         printk(KERN_NOTICE "Concatenating MTD devices:\n");
 650         for (i = 0; i < num_devs; i++)
 651                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 652         printk(KERN_NOTICE "into device \"%s\"\n", name);
 653
 654         /* allocate the device structure */
 655         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 656         concat = kzalloc(size, GFP_KERNEL);
 657         if (!concat) {
 658                 printk
 659                     ("memory allocation error while creating concatenated device \"%s\"\n",
 660                      name);
 661                 return NULL;
 662         }
 663         concat->subdev = (struct mtd_info **) (concat + 1);
 664
 665         /*
 666          * Set up the new "super" device's MTD object structure, check for
 667          * incompatibilities between the subdevices.
 668          */
 669         concat->mtd.type = subdev[0]->type;
 670         concat->mtd.flags = subdev[0]->flags;
 671         concat->mtd.size = subdev[0]->size;
 672         concat->mtd.erasesize = subdev[0]->erasesize;
 673         concat->mtd.writesize = subdev[0]->writesize;
 674
 675         for (i = 0; i < num_devs; i++)
 676                 if (max_writebufsize < subdev[i]->writebufsize)
 677                         max_writebufsize = subdev[i]->writebufsize;
 678         concat->mtd.writebufsize = max_writebufsize;
 679
 680         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 681         concat->mtd.oobsize = subdev[0]->oobsize;
 682         concat->mtd.oobavail = subdev[0]->oobavail;
 683
 684         subdev_master = mtd_get_master(subdev[0]);
 685         if (subdev_master->_writev)
 686                 concat->mtd._writev = concat_writev;
 687         if (subdev_master->_read_oob)
 688                 concat->mtd._read_oob = concat_read_oob;
 689         if (subdev_master->_write_oob)
 690                 concat->mtd._write_oob = concat_write_oob;
 691         if (subdev_master->_block_isbad)
 692                 concat->mtd._block_isbad = concat_block_isbad;
 693         if (subdev_master->_block_markbad)
 694                 concat->mtd._block_markbad = concat_block_markbad;
 695         if (subdev_master->_panic_write)
 696                 concat->mtd._panic_write = concat_panic_write;
 697         if (subdev_master->_read)
 698                 concat->mtd._read = concat_read;
 699         if (subdev_master->_write)
 700                 concat->mtd._write = concat_write;
 701
 702         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 703
 704         concat->subdev[0] = subdev[0];
 705
 706         for (i = 1; i < num_devs; i++) {
 707                 if (concat->mtd.type != subdev[i]->type) {
 708                         kfree(concat);
 709                         printk("Incompatible device type on \"%s\"\n",
 710                                subdev[i]->name);
 711                         return NULL;
 712                 }
 713                 if (concat->mtd.flags != subdev[i]->flags) {
 714                         /*
 715                          * Expect all flags except MTD_WRITEABLE to be
 716                          * equal on all subdevices.
 717                          */
 718                         if ((concat->mtd.flags ^ subdev[i]->
 719                              flags) & ~MTD_WRITEABLE) {
 720                                 kfree(concat);
 721                                 printk("Incompatible device flags on \"%s\"\n",
 722                                        subdev[i]->name);
 723                                 return NULL;
 724                         } else
 725                                 /* if writeable attribute differs,
 726                                    make super device writeable */
 727                                 concat->mtd.flags |=
 728                                     subdev[i]->flags & MTD_WRITEABLE;
 729                 }
 730
 731                 subdev_master = mtd_get_master(subdev[i]);
 732                 concat->mtd.size += subdev[i]->size;
 733                 concat->mtd.ecc_stats.badblocks +=
 734                         subdev[i]->ecc_stats.badblocks;
 735                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 736                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 737                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 738                     !concat->mtd._read_oob  != !subdev_master->_read_oob ||
 739                     !concat->mtd._write_oob != !subdev_master->_write_oob) {
 740                         /*
 741                          * Check against subdev[i] for data members, because
 742                          * subdev's attributes may be different from master
 743                          * mtd device. Check against subdev's master mtd
 744                          * device for callbacks, because the existence of
 745                          * subdev's callbacks is decided by master mtd device.
 746                          */
 747                         kfree(concat);
 748                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 749                                subdev[i]->name);
 750                         return NULL;
 751                 }
 752                 concat->subdev[i] = subdev[i];
 753
 754         }
 755
 756         mtd_set_ooblayout(&concat->mtd, subdev[0]->ooblayout);
 757
 758         concat->num_subdev = num_devs;
 759         concat->mtd.name = name;
 760
 761         concat->mtd._erase = concat_erase;
 762         concat->mtd._sync = concat_sync;
 763         concat->mtd._lock = concat_lock;
 764         concat->mtd._unlock = concat_unlock;
 765         concat->mtd._is_locked = concat_is_locked;
 766         concat->mtd._suspend = concat_suspend;
 767         concat->mtd._resume = concat_resume;
 768
 769         /*
 770          * Combine the erase block size info of the subdevices:
 771          *
 772          * first, walk the map of the new device and see how
 773          * many changes in erase size we have
 774          */
 775         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 776         num_erase_region = 1;
 777         for (i = 0; i < num_devs; i++) {
 778                 if (subdev[i]->numeraseregions == 0) {
 779                         /* current subdevice has uniform erase size */
 780                         if (subdev[i]->erasesize != curr_erasesize) {
 781                                 /* if it differs from the last subdevice's erase size, count it */
 782                                 ++num_erase_region;
 783                                 curr_erasesize = subdev[i]->erasesize;
 784                                 if (curr_erasesize > max_erasesize)
 785                                         max_erasesize = curr_erasesize;
 786                         }
 787                 } else {
 788                         /* current subdevice has variable erase size */
 789                         int j;
 790                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 791
 792                                 /* walk the list of erase regions, count any changes */
 793                                 if (subdev[i]->eraseregions[j].erasesize !=
 794                                     curr_erasesize) {
 795                                         ++num_erase_region;
 796                                         curr_erasesize =
 797                                             subdev[i]->eraseregions[j].
 798                                             erasesize;
 799                                         if (curr_erasesize > max_erasesize)
 800                                                 max_erasesize = curr_erasesize;
 801                                 }
 802                         }
 803                 }
 804         }
 805
 806         if (num_erase_region == 1) {
 807                 /*
 808                  * All subdevices have the same uniform erase size.
 809                  * This is easy:
 810                  */
 811                 concat->mtd.erasesize = curr_erasesize;
 812                 concat->mtd.numeraseregions = 0;
 813         } else {
 814                 uint64_t tmp64;
 815
 816                 /*
 817                  * erase block size varies across the subdevices: allocate
 818                  * space to store the data describing the variable erase regions
 819                  */
 820                 struct mtd_erase_region_info *erase_region_p;
 821                 uint64_t begin, position;
 822
 823                 concat->mtd.erasesize = max_erasesize;
 824                 concat->mtd.numeraseregions = num_erase_region;
 825                 concat->mtd.eraseregions = erase_region_p =
 826                     kmalloc_array(num_erase_region,
 827                                   sizeof(struct mtd_erase_region_info),
 828                                   GFP_KERNEL);
 829                 if (!erase_region_p) {
 830                         kfree(concat);
 831                         printk
 832                             ("memory allocation error while creating erase region list"
 833                              " for device \"%s\"\n", name);
 834                         return NULL;
 835                 }
 836
 837                 /*
 838                  * walk the map of the new device once more and fill in
 839                  * in erase region info:
 840                  */
 841                 curr_erasesize = subdev[0]->erasesize;
 842                 begin = position = 0;
 843                 for (i = 0; i < num_devs; i++) {
 844                         if (subdev[i]->numeraseregions == 0) {
 845                                 /* current subdevice has uniform erase size */
 846                                 if (subdev[i]->erasesize != curr_erasesize) {
 847                                         /*
 848                                          *  fill in an mtd_erase_region_info structure for the area
 849                                          *  we have walked so far:
 850                                          */
 851                                         erase_region_p->offset = begin;
 852                                         erase_region_p->erasesize =
 853                                             curr_erasesize;
 854                                         tmp64 = position - begin;
 855                                         do_div(tmp64, curr_erasesize);
 856                                         erase_region_p->numblocks = tmp64;
 857                                         begin = position;
 858
 859                                         curr_erasesize = subdev[i]->erasesize;
 860                                         ++erase_region_p;
 861                                 }
 862                                 position += subdev[i]->size;
 863                         } else {
 864                                 /* current subdevice has variable erase size */
 865                                 int j;
 866                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 867                                         /* walk the list of erase regions, count any changes */
 868                                         if (subdev[i]->eraseregions[j].
 869                                             erasesize != curr_erasesize) {
 870                                                 erase_region_p->offset = begin;
 871                                                 erase_region_p->erasesize =
 872                                                     curr_erasesize;
 873                                                 tmp64 = position - begin;
 874                                                 do_div(tmp64, curr_erasesize);
 875                                                 erase_region_p->numblocks = tmp64;
 876                                                 begin = position;
 877
 878                                                 curr_erasesize =
 879                                                     subdev[i]->eraseregions[j].
 880                                                     erasesize;
 881                                                 ++erase_region_p;
 882                                         }
 883                                         position +=
 884                                             subdev[i]->eraseregions[j].
 885                                             numblocks * (uint64_t)curr_erasesize;
 886                                 }
 887                         }
 888                 }
 889                 /* Now write the final entry */
 890                 erase_region_p->offset = begin;
 891                 erase_region_p->erasesize = curr_erasesize;
 892                 tmp64 = position - begin;
 893                 do_div(tmp64, curr_erasesize);
 894                 erase_region_p->numblocks = tmp64;
 895         }
 896
 897         return &concat->mtd;
 898 }
 899
 900 /* Cleans the context obtained from mtd_concat_create() */
 901 void mtd_concat_destroy(struct mtd_info *mtd)
 902 {
 903         struct mtd_concat *concat = CONCAT(mtd);
 904         if (concat->mtd.numeraseregions)
 905                 kfree(concat->mtd.eraseregions);
 906         kfree(concat);
 907 }
 908
 909 EXPORT_SYMBOL(mtd_concat_create);
 910 EXPORT_SYMBOL(mtd_concat_destroy);
 911
 912 MODULE_LICENSE("GPL");
 913 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 914 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");