drivers/mtd/mtdconcat.c

   1 // SPDX-License-Identifier: GPL-2.0+
   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
  12 #ifndef __UBOOT__
  13 #include <log.h>
  14 #include <dm/devres.h>
  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/bug.h>
  25 #include <linux/compat.h>
  26 #endif
  27
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/concat.h>
  30
  31 #include <ubi_uboot.h>
  32
  33 /*
  34  * Our storage structure:
  35  * Subdev points to an array of pointers to struct mtd_info objects
  36  * which is allocated along with this structure
  37  *
  38  */
  39 struct mtd_concat {
  40         struct mtd_info mtd;
  41         int num_subdev;
  42         struct mtd_info **subdev;
  43 };
  44
  45 /*
  46  * how to calculate the size required for the above structure,
  47  * including the pointer array subdev points to:
  48  */
  49 #define SIZEOF_STRUCT_MTD_CONCAT(num_subdev)    \
  50         ((sizeof(struct mtd_concat) + (num_subdev) * sizeof(struct mtd_info *)))
  51
  52 /*
  53  * Given a pointer to the MTD object in the mtd_concat structure,
  54  * we can retrieve the pointer to that structure with this macro.
  55  */
  56 #define CONCAT(x)  ((struct mtd_concat *)(x))
  57
  58 /*
  59  * MTD methods which look up the relevant subdevice, translate the
  60  * effective address and pass through to the subdevice.
  61  */
  62
  63 static int
  64 concat_read(struct mtd_info *mtd, loff_t from, size_t len,
  65             size_t * retlen, u_char * buf)
  66 {
  67         struct mtd_concat *concat = CONCAT(mtd);
  68         int ret = 0, err;
  69         int i;
  70
  71 #ifdef __UBOOT__
  72         *retlen = 0;
  73 #endif
  74
  75         for (i = 0; i < concat->num_subdev; i++) {
  76                 struct mtd_info *subdev = concat->subdev[i];
  77                 size_t size, retsize;
  78
  79                 if (from >= subdev->size) {
  80                         /* Not destined for this subdev */
  81                         size = 0;
  82                         from -= subdev->size;
  83                         continue;
  84                 }
  85                 if (from + len > subdev->size)
  86                         /* First part goes into this subdev */
  87                         size = subdev->size - from;
  88                 else
  89                         /* Entire transaction goes into this subdev */
  90                         size = len;
  91
  92                 err = mtd_read(subdev, from, size, &retsize, buf);
  93
  94                 /* Save information about bitflips! */
  95                 if (unlikely(err)) {
  96                         if (mtd_is_eccerr(err)) {
  97                                 mtd->ecc_stats.failed++;
  98                                 ret = err;
  99                         } else if (mtd_is_bitflip(err)) {
 100                                 mtd->ecc_stats.corrected++;
 101                                 /* Do not overwrite -EBADMSG !! */
 102                                 if (!ret)
 103                                         ret = err;
 104                         } else
 105                                 return err;
 106                 }
 107
 108                 *retlen += retsize;
 109                 len -= size;
 110                 if (len == 0)
 111                         return ret;
 112
 113                 buf += size;
 114                 from = 0;
 115         }
 116         return -EINVAL;
 117 }
 118
 119 static int
 120 concat_write(struct mtd_info *mtd, loff_t to, size_t len,
 121              size_t * retlen, const u_char * buf)
 122 {
 123         struct mtd_concat *concat = CONCAT(mtd);
 124         int err = -EINVAL;
 125         int i;
 126
 127 #ifdef __UBOOT__
 128         *retlen = 0;
 129 #endif
 130
 131         for (i = 0; i < concat->num_subdev; i++) {
 132                 struct mtd_info *subdev = concat->subdev[i];
 133                 size_t size, retsize;
 134
 135                 if (to >= subdev->size) {
 136                         size = 0;
 137                         to -= subdev->size;
 138                         continue;
 139                 }
 140                 if (to + len > subdev->size)
 141                         size = subdev->size - to;
 142                 else
 143                         size = len;
 144
 145                 err = mtd_write(subdev, to, size, &retsize, buf);
 146                 if (err)
 147                         break;
 148
 149                 *retlen += retsize;
 150                 len -= size;
 151                 if (len == 0)
 152                         break;
 153
 154                 err = -EINVAL;
 155                 buf += size;
 156                 to = 0;
 157         }
 158         return err;
 159 }
 160
 161 #ifndef __UBOOT__
 162 static int
 163 concat_writev(struct mtd_info *mtd, const struct kvec *vecs,
 164                 unsigned long count, loff_t to, size_t * retlen)
 165 {
 166         struct mtd_concat *concat = CONCAT(mtd);
 167         struct kvec *vecs_copy;
 168         unsigned long entry_low, entry_high;
 169         size_t total_len = 0;
 170         int i;
 171         int err = -EINVAL;
 172
 173         /* Calculate total length of data */
 174         for (i = 0; i < count; i++)
 175                 total_len += vecs[i].iov_len;
 176
 177         /* Check alignment */
 178         if (mtd->writesize > 1) {
 179                 uint64_t __to = to;
 180                 if (do_div(__to, mtd->writesize) || (total_len % mtd->writesize))
 181                         return -EINVAL;
 182         }
 183
 184         /* make a copy of vecs */
 185         vecs_copy = kmemdup(vecs, sizeof(struct kvec) * count, GFP_KERNEL);
 186         if (!vecs_copy)
 187                 return -ENOMEM;
 188
 189         entry_low = 0;
 190         for (i = 0; i < concat->num_subdev; i++) {
 191                 struct mtd_info *subdev = concat->subdev[i];
 192                 size_t size, wsize, retsize, old_iov_len;
 193
 194                 if (to >= subdev->size) {
 195                         to -= subdev->size;
 196                         continue;
 197                 }
 198
 199                 size = min_t(uint64_t, total_len, subdev->size - to);
 200                 wsize = size; /* store for future use */
 201
 202                 entry_high = entry_low;
 203                 while (entry_high < count) {
 204                         if (size <= vecs_copy[entry_high].iov_len)
 205                                 break;
 206                         size -= vecs_copy[entry_high++].iov_len;
 207                 }
 208
 209                 old_iov_len = vecs_copy[entry_high].iov_len;
 210                 vecs_copy[entry_high].iov_len = size;
 211
 212                 err = mtd_writev(subdev, &vecs_copy[entry_low],
 213                                  entry_high - entry_low + 1, to, &retsize);
 214
 215                 vecs_copy[entry_high].iov_len = old_iov_len - size;
 216                 vecs_copy[entry_high].iov_base += size;
 217
 218                 entry_low = entry_high;
 219
 220                 if (err)
 221                         break;
 222
 223                 *retlen += retsize;
 224                 total_len -= wsize;
 225
 226                 if (total_len == 0)
 227                         break;
 228
 229                 err = -EINVAL;
 230                 to = 0;
 231         }
 232
 233         kfree(vecs_copy);
 234         return err;
 235 }
 236 #endif
 237
 238 static int
 239 concat_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops)
 240 {
 241         struct mtd_concat *concat = CONCAT(mtd);
 242         struct mtd_oob_ops devops = *ops;
 243         int i, err, ret = 0;
 244
 245         ops->retlen = ops->oobretlen = 0;
 246
 247         for (i = 0; i < concat->num_subdev; i++) {
 248                 struct mtd_info *subdev = concat->subdev[i];
 249
 250                 if (from >= subdev->size) {
 251                         from -= subdev->size;
 252                         continue;
 253                 }
 254
 255                 /* partial read ? */
 256                 if (from + devops.len > subdev->size)
 257                         devops.len = subdev->size - from;
 258
 259                 err = mtd_read_oob(subdev, from, &devops);
 260                 ops->retlen += devops.retlen;
 261                 ops->oobretlen += devops.oobretlen;
 262
 263                 /* Save information about bitflips! */
 264                 if (unlikely(err)) {
 265                         if (mtd_is_eccerr(err)) {
 266                                 mtd->ecc_stats.failed++;
 267                                 ret = err;
 268                         } else if (mtd_is_bitflip(err)) {
 269                                 mtd->ecc_stats.corrected++;
 270                                 /* Do not overwrite -EBADMSG !! */
 271                                 if (!ret)
 272                                         ret = err;
 273                         } else
 274                                 return err;
 275                 }
 276
 277                 if (devops.datbuf) {
 278                         devops.len = ops->len - ops->retlen;
 279                         if (!devops.len)
 280                                 return ret;
 281                         devops.datbuf += devops.retlen;
 282                 }
 283                 if (devops.oobbuf) {
 284                         devops.ooblen = ops->ooblen - ops->oobretlen;
 285                         if (!devops.ooblen)
 286                                 return ret;
 287                         devops.oobbuf += ops->oobretlen;
 288                 }
 289
 290                 from = 0;
 291         }
 292         return -EINVAL;
 293 }
 294
 295 static int
 296 concat_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops)
 297 {
 298         struct mtd_concat *concat = CONCAT(mtd);
 299         struct mtd_oob_ops devops = *ops;
 300         int i, err;
 301
 302         if (!(mtd->flags & MTD_WRITEABLE))
 303                 return -EROFS;
 304
 305         ops->retlen = ops->oobretlen = 0;
 306
 307         for (i = 0; i < concat->num_subdev; i++) {
 308                 struct mtd_info *subdev = concat->subdev[i];
 309
 310                 if (to >= subdev->size) {
 311                         to -= subdev->size;
 312                         continue;
 313                 }
 314
 315                 /* partial write ? */
 316                 if (to + devops.len > subdev->size)
 317                         devops.len = subdev->size - to;
 318
 319                 err = mtd_write_oob(subdev, to, &devops);
 320                 ops->retlen += devops.oobretlen;
 321                 if (err)
 322                         return err;
 323
 324                 if (devops.datbuf) {
 325                         devops.len = ops->len - ops->retlen;
 326                         if (!devops.len)
 327                                 return 0;
 328                         devops.datbuf += devops.retlen;
 329                 }
 330                 if (devops.oobbuf) {
 331                         devops.ooblen = ops->ooblen - ops->oobretlen;
 332                         if (!devops.ooblen)
 333                                 return 0;
 334                         devops.oobbuf += devops.oobretlen;
 335                 }
 336                 to = 0;
 337         }
 338         return -EINVAL;
 339 }
 340
 341 static void concat_erase_callback(struct erase_info *instr)
 342 {
 343         /* Nothing to do here in U-Boot */
 344 #ifndef __UBOOT__
 345         wake_up((wait_queue_head_t *) instr->priv);
 346 #endif
 347 }
 348
 349 static int concat_dev_erase(struct mtd_info *mtd, struct erase_info *erase)
 350 {
 351         int err;
 352         wait_queue_head_t waitq;
 353         DECLARE_WAITQUEUE(wait, current);
 354
 355         /*
 356          * This code was stol^H^H^H^Hinspired by mtdchar.c
 357          */
 358         init_waitqueue_head(&waitq);
 359
 360         erase->mtd = mtd;
 361         erase->callback = concat_erase_callback;
 362         erase->priv = (unsigned long) &waitq;
 363
 364         /*
 365          * FIXME: Allow INTERRUPTIBLE. Which means
 366          * not having the wait_queue head on the stack.
 367          */
 368         err = mtd_erase(mtd, erase);
 369         if (!err) {
 370                 set_current_state(TASK_UNINTERRUPTIBLE);
 371                 add_wait_queue(&waitq, &wait);
 372                 if (erase->state != MTD_ERASE_DONE
 373                     && erase->state != MTD_ERASE_FAILED)
 374                         schedule();
 375                 remove_wait_queue(&waitq, &wait);
 376                 set_current_state(TASK_RUNNING);
 377
 378                 err = (erase->state == MTD_ERASE_FAILED) ? -EIO : 0;
 379         }
 380         return err;
 381 }
 382
 383 static int concat_erase(struct mtd_info *mtd, struct erase_info *instr)
 384 {
 385         struct mtd_concat *concat = CONCAT(mtd);
 386         struct mtd_info *subdev;
 387         int i, err;
 388         uint64_t length, offset = 0;
 389         struct erase_info *erase;
 390
 391         /*
 392          * Check for proper erase block alignment of the to-be-erased area.
 393          * It is easier to do this based on the super device's erase
 394          * region info rather than looking at each particular sub-device
 395          * in turn.
 396          */
 397         if (!concat->mtd.numeraseregions) {
 398                 /* the easy case: device has uniform erase block size */
 399                 if (instr->addr & (concat->mtd.erasesize - 1))
 400                         return -EINVAL;
 401                 if (instr->len & (concat->mtd.erasesize - 1))
 402                         return -EINVAL;
 403         } else {
 404                 /* device has variable erase size */
 405                 struct mtd_erase_region_info *erase_regions =
 406                     concat->mtd.eraseregions;
 407
 408                 /*
 409                  * Find the erase region where the to-be-erased area begins:
 410                  */
 411                 for (i = 0; i < concat->mtd.numeraseregions &&
 412                      instr->addr >= erase_regions[i].offset; i++) ;
 413                 --i;
 414
 415                 /*
 416                  * Now erase_regions[i] is the region in which the
 417                  * to-be-erased area begins. Verify that the starting
 418                  * offset is aligned to this region's erase size:
 419                  */
 420                 if (i < 0 || instr->addr & (erase_regions[i].erasesize - 1))
 421                         return -EINVAL;
 422
 423                 /*
 424                  * now find the erase region where the to-be-erased area ends:
 425                  */
 426                 for (; i < concat->mtd.numeraseregions &&
 427                      (instr->addr + instr->len) >= erase_regions[i].offset;
 428                      ++i) ;
 429                 --i;
 430                 /*
 431                  * check if the ending offset is aligned to this region's erase size
 432                  */
 433                 if (i < 0 || ((instr->addr + instr->len) &
 434                                         (erase_regions[i].erasesize - 1)))
 435                         return -EINVAL;
 436         }
 437
 438         /* make a local copy of instr to avoid modifying the caller's struct */
 439         erase = kmalloc(sizeof (struct erase_info), GFP_KERNEL);
 440
 441         if (!erase)
 442                 return -ENOMEM;
 443
 444         *erase = *instr;
 445         length = instr->len;
 446
 447         /*
 448          * find the subdevice where the to-be-erased area begins, adjust
 449          * starting offset to be relative to the subdevice start
 450          */
 451         for (i = 0; i < concat->num_subdev; i++) {
 452                 subdev = concat->subdev[i];
 453                 if (subdev->size <= erase->addr) {
 454                         erase->addr -= subdev->size;
 455                         offset += subdev->size;
 456                 } else {
 457                         break;
 458                 }
 459         }
 460
 461         /* must never happen since size limit has been verified above */
 462         BUG_ON(i >= concat->num_subdev);
 463
 464         /* now do the erase: */
 465         err = 0;
 466         for (; length > 0; i++) {
 467                 /* loop for all subdevices affected by this request */
 468                 subdev = concat->subdev[i];     /* get current subdevice */
 469
 470                 /* limit length to subdevice's size: */
 471                 if (erase->addr + length > subdev->size)
 472                         erase->len = subdev->size - erase->addr;
 473                 else
 474                         erase->len = length;
 475
 476                 length -= erase->len;
 477                 if ((err = concat_dev_erase(subdev, erase))) {
 478                         /* sanity check: should never happen since
 479                          * block alignment has been checked above */
 480                         BUG_ON(err == -EINVAL);
 481                         if (erase->fail_addr != MTD_FAIL_ADDR_UNKNOWN)
 482                                 instr->fail_addr = erase->fail_addr + offset;
 483                         break;
 484                 }
 485                 /*
 486                  * erase->addr specifies the offset of the area to be
 487                  * erased *within the current subdevice*. It can be
 488                  * non-zero only the first time through this loop, i.e.
 489                  * for the first subdevice where blocks need to be erased.
 490                  * All the following erases must begin at the start of the
 491                  * current subdevice, i.e. at offset zero.
 492                  */
 493                 erase->addr = 0;
 494                 offset += subdev->size;
 495         }
 496         instr->state = erase->state;
 497         kfree(erase);
 498         if (err)
 499                 return err;
 500
 501         if (instr->callback)
 502                 instr->callback(instr);
 503         return 0;
 504 }
 505
 506 static int concat_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 507 {
 508         struct mtd_concat *concat = CONCAT(mtd);
 509         int i, err = -EINVAL;
 510
 511         for (i = 0; i < concat->num_subdev; i++) {
 512                 struct mtd_info *subdev = concat->subdev[i];
 513                 uint64_t size;
 514
 515                 if (ofs >= subdev->size) {
 516                         size = 0;
 517                         ofs -= subdev->size;
 518                         continue;
 519                 }
 520                 if (ofs + len > subdev->size)
 521                         size = subdev->size - ofs;
 522                 else
 523                         size = len;
 524
 525                 err = mtd_lock(subdev, ofs, size);
 526                 if (err)
 527                         break;
 528
 529                 len -= size;
 530                 if (len == 0)
 531                         break;
 532
 533                 err = -EINVAL;
 534                 ofs = 0;
 535         }
 536
 537         return err;
 538 }
 539
 540 static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 541 {
 542         struct mtd_concat *concat = CONCAT(mtd);
 543         int i, err = 0;
 544
 545         for (i = 0; i < concat->num_subdev; i++) {
 546                 struct mtd_info *subdev = concat->subdev[i];
 547                 uint64_t size;
 548
 549                 if (ofs >= subdev->size) {
 550                         size = 0;
 551                         ofs -= subdev->size;
 552                         continue;
 553                 }
 554                 if (ofs + len > subdev->size)
 555                         size = subdev->size - ofs;
 556                 else
 557                         size = len;
 558
 559                 err = mtd_unlock(subdev, ofs, size);
 560                 if (err)
 561                         break;
 562
 563                 len -= size;
 564                 if (len == 0)
 565                         break;
 566
 567                 err = -EINVAL;
 568                 ofs = 0;
 569         }
 570
 571         return err;
 572 }
 573
 574 static void concat_sync(struct mtd_info *mtd)
 575 {
 576         struct mtd_concat *concat = CONCAT(mtd);
 577         int i;
 578
 579         for (i = 0; i < concat->num_subdev; i++) {
 580                 struct mtd_info *subdev = concat->subdev[i];
 581                 mtd_sync(subdev);
 582         }
 583 }
 584
 585 #ifndef __UBOOT__
 586 static int concat_suspend(struct mtd_info *mtd)
 587 {
 588         struct mtd_concat *concat = CONCAT(mtd);
 589         int i, rc = 0;
 590
 591         for (i = 0; i < concat->num_subdev; i++) {
 592                 struct mtd_info *subdev = concat->subdev[i];
 593                 if ((rc = mtd_suspend(subdev)) < 0)
 594                         return rc;
 595         }
 596         return rc;
 597 }
 598
 599 static void concat_resume(struct mtd_info *mtd)
 600 {
 601         struct mtd_concat *concat = CONCAT(mtd);
 602         int i;
 603
 604         for (i = 0; i < concat->num_subdev; i++) {
 605                 struct mtd_info *subdev = concat->subdev[i];
 606                 mtd_resume(subdev);
 607         }
 608 }
 609 #endif
 610
 611 static int concat_block_isbad(struct mtd_info *mtd, loff_t ofs)
 612 {
 613         struct mtd_concat *concat = CONCAT(mtd);
 614         int i, res = 0;
 615
 616         if (!mtd_can_have_bb(concat->subdev[0]))
 617                 return res;
 618
 619         for (i = 0; i < concat->num_subdev; i++) {
 620                 struct mtd_info *subdev = concat->subdev[i];
 621
 622                 if (ofs >= subdev->size) {
 623                         ofs -= subdev->size;
 624                         continue;
 625                 }
 626
 627                 res = mtd_block_isbad(subdev, ofs);
 628                 break;
 629         }
 630
 631         return res;
 632 }
 633
 634 static int concat_block_markbad(struct mtd_info *mtd, loff_t ofs)
 635 {
 636         struct mtd_concat *concat = CONCAT(mtd);
 637         int i, err = -EINVAL;
 638
 639         for (i = 0; i < concat->num_subdev; i++) {
 640                 struct mtd_info *subdev = concat->subdev[i];
 641
 642                 if (ofs >= subdev->size) {
 643                         ofs -= subdev->size;
 644                         continue;
 645                 }
 646
 647                 err = mtd_block_markbad(subdev, ofs);
 648                 if (!err)
 649                         mtd->ecc_stats.badblocks++;
 650                 break;
 651         }
 652
 653         return err;
 654 }
 655
 656 /*
 657  * try to support NOMMU mmaps on concatenated devices
 658  * - we don't support subdev spanning as we can't guarantee it'll work
 659  */
 660 static unsigned long concat_get_unmapped_area(struct mtd_info *mtd,
 661                                               unsigned long len,
 662                                               unsigned long offset,
 663                                               unsigned long flags)
 664 {
 665         struct mtd_concat *concat = CONCAT(mtd);
 666         int i;
 667
 668         for (i = 0; i < concat->num_subdev; i++) {
 669                 struct mtd_info *subdev = concat->subdev[i];
 670
 671                 if (offset >= subdev->size) {
 672                         offset -= subdev->size;
 673                         continue;
 674                 }
 675
 676                 return mtd_get_unmapped_area(subdev, len, offset, flags);
 677         }
 678
 679         return (unsigned long) -ENOSYS;
 680 }
 681
 682 /*
 683  * This function constructs a virtual MTD device by concatenating
 684  * num_devs MTD devices. A pointer to the new device object is
 685  * stored to *new_dev upon success. This function does _not_
 686  * register any devices: this is the caller's responsibility.
 687  */
 688 struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],   /* subdevices to concatenate */
 689                                    int num_devs,        /* number of subdevices      */
 690 #ifndef __UBOOT__
 691                                    const char *name)
 692 #else
 693                                    char *name)
 694 #endif
 695 {                               /* name for the new device   */
 696         int i;
 697         size_t size;
 698         struct mtd_concat *concat;
 699         uint32_t max_erasesize, curr_erasesize;
 700         int num_erase_region;
 701         int max_writebufsize = 0;
 702
 703         debug("Concatenating MTD devices:\n");
 704         for (i = 0; i < num_devs; i++)
 705                 printk(KERN_NOTICE "(%d): \"%s\"\n", i, subdev[i]->name);
 706         debug("into device \"%s\"\n", name);
 707
 708         /* allocate the device structure */
 709         size = SIZEOF_STRUCT_MTD_CONCAT(num_devs);
 710         concat = kzalloc(size, GFP_KERNEL);
 711         if (!concat) {
 712                 printk
 713                     ("memory allocation error while creating concatenated device \"%s\"\n",
 714                      name);
 715                 return NULL;
 716         }
 717         concat->subdev = (struct mtd_info **) (concat + 1);
 718
 719         /*
 720          * Set up the new "super" device's MTD object structure, check for
 721          * incompatibilities between the subdevices.
 722          */
 723         concat->mtd.type = subdev[0]->type;
 724         concat->mtd.flags = subdev[0]->flags;
 725         concat->mtd.size = subdev[0]->size;
 726         concat->mtd.erasesize = subdev[0]->erasesize;
 727         concat->mtd.writesize = subdev[0]->writesize;
 728
 729         for (i = 0; i < num_devs; i++)
 730                 if (max_writebufsize < subdev[i]->writebufsize)
 731                         max_writebufsize = subdev[i]->writebufsize;
 732         concat->mtd.writebufsize = max_writebufsize;
 733
 734         concat->mtd.subpage_sft = subdev[0]->subpage_sft;
 735         concat->mtd.oobsize = subdev[0]->oobsize;
 736         concat->mtd.oobavail = subdev[0]->oobavail;
 737 #ifndef __UBOOT__
 738         if (subdev[0]->_writev)
 739                 concat->mtd._writev = concat_writev;
 740 #endif
 741         if (subdev[0]->_read_oob)
 742                 concat->mtd._read_oob = concat_read_oob;
 743         if (subdev[0]->_write_oob)
 744                 concat->mtd._write_oob = concat_write_oob;
 745         if (subdev[0]->_block_isbad)
 746                 concat->mtd._block_isbad = concat_block_isbad;
 747         if (subdev[0]->_block_markbad)
 748                 concat->mtd._block_markbad = concat_block_markbad;
 749
 750         concat->mtd.ecc_stats.badblocks = subdev[0]->ecc_stats.badblocks;
 751
 752 #ifndef __UBOOT__
 753         concat->mtd.backing_dev_info = subdev[0]->backing_dev_info;
 754 #endif
 755
 756         concat->subdev[0] = subdev[0];
 757
 758         for (i = 1; i < num_devs; i++) {
 759                 if (concat->mtd.type != subdev[i]->type) {
 760                         kfree(concat);
 761                         printk("Incompatible device type on \"%s\"\n",
 762                                subdev[i]->name);
 763                         return NULL;
 764                 }
 765                 if (concat->mtd.flags != subdev[i]->flags) {
 766                         /*
 767                          * Expect all flags except MTD_WRITEABLE to be
 768                          * equal on all subdevices.
 769                          */
 770                         if ((concat->mtd.flags ^ subdev[i]->
 771                              flags) & ~MTD_WRITEABLE) {
 772                                 kfree(concat);
 773                                 printk("Incompatible device flags on \"%s\"\n",
 774                                        subdev[i]->name);
 775                                 return NULL;
 776                         } else
 777                                 /* if writeable attribute differs,
 778                                    make super device writeable */
 779                                 concat->mtd.flags |=
 780                                     subdev[i]->flags & MTD_WRITEABLE;
 781                 }
 782
 783 #ifndef __UBOOT__
 784                 /* only permit direct mapping if the BDIs are all the same
 785                  * - copy-mapping is still permitted
 786                  */
 787                 if (concat->mtd.backing_dev_info !=
 788                     subdev[i]->backing_dev_info)
 789                         concat->mtd.backing_dev_info =
 790                                 &default_backing_dev_info;
 791 #endif
 792
 793                 concat->mtd.size += subdev[i]->size;
 794                 concat->mtd.ecc_stats.badblocks +=
 795                         subdev[i]->ecc_stats.badblocks;
 796                 if (concat->mtd.writesize   !=  subdev[i]->writesize ||
 797                     concat->mtd.subpage_sft != subdev[i]->subpage_sft ||
 798                     concat->mtd.oobsize    !=  subdev[i]->oobsize ||
 799                     !concat->mtd._read_oob  != !subdev[i]->_read_oob ||
 800                     !concat->mtd._write_oob != !subdev[i]->_write_oob) {
 801                         kfree(concat);
 802                         printk("Incompatible OOB or ECC data on \"%s\"\n",
 803                                subdev[i]->name);
 804                         return NULL;
 805                 }
 806                 concat->subdev[i] = subdev[i];
 807
 808         }
 809
 810         concat->mtd.ecclayout = subdev[0]->ecclayout;
 811
 812         concat->num_subdev = num_devs;
 813         concat->mtd.name = name;
 814
 815         concat->mtd._erase = concat_erase;
 816         concat->mtd._read = concat_read;
 817         concat->mtd._write = concat_write;
 818         concat->mtd._sync = concat_sync;
 819         concat->mtd._lock = concat_lock;
 820         concat->mtd._unlock = concat_unlock;
 821 #ifndef __UBOOT__
 822         concat->mtd._suspend = concat_suspend;
 823         concat->mtd._resume = concat_resume;
 824 #endif
 825         concat->mtd._get_unmapped_area = concat_get_unmapped_area;
 826
 827         /*
 828          * Combine the erase block size info of the subdevices:
 829          *
 830          * first, walk the map of the new device and see how
 831          * many changes in erase size we have
 832          */
 833         max_erasesize = curr_erasesize = subdev[0]->erasesize;
 834         num_erase_region = 1;
 835         for (i = 0; i < num_devs; i++) {
 836                 if (subdev[i]->numeraseregions == 0) {
 837                         /* current subdevice has uniform erase size */
 838                         if (subdev[i]->erasesize != curr_erasesize) {
 839                                 /* if it differs from the last subdevice's erase size, count it */
 840                                 ++num_erase_region;
 841                                 curr_erasesize = subdev[i]->erasesize;
 842                                 if (curr_erasesize > max_erasesize)
 843                                         max_erasesize = curr_erasesize;
 844                         }
 845                 } else {
 846                         /* current subdevice has variable erase size */
 847                         int j;
 848                         for (j = 0; j < subdev[i]->numeraseregions; j++) {
 849
 850                                 /* walk the list of erase regions, count any changes */
 851                                 if (subdev[i]->eraseregions[j].erasesize !=
 852                                     curr_erasesize) {
 853                                         ++num_erase_region;
 854                                         curr_erasesize =
 855                                             subdev[i]->eraseregions[j].
 856                                             erasesize;
 857                                         if (curr_erasesize > max_erasesize)
 858                                                 max_erasesize = curr_erasesize;
 859                                 }
 860                         }
 861                 }
 862         }
 863
 864         if (num_erase_region == 1) {
 865                 /*
 866                  * All subdevices have the same uniform erase size.
 867                  * This is easy:
 868                  */
 869                 concat->mtd.erasesize = curr_erasesize;
 870                 concat->mtd.numeraseregions = 0;
 871         } else {
 872                 uint64_t tmp64;
 873
 874                 /*
 875                  * erase block size varies across the subdevices: allocate
 876                  * space to store the data describing the variable erase regions
 877                  */
 878                 struct mtd_erase_region_info *erase_region_p;
 879                 uint64_t begin, position;
 880
 881                 concat->mtd.erasesize = max_erasesize;
 882                 concat->mtd.numeraseregions = num_erase_region;
 883                 concat->mtd.eraseregions = erase_region_p =
 884                     kmalloc(num_erase_region *
 885                             sizeof (struct mtd_erase_region_info), GFP_KERNEL);
 886                 if (!erase_region_p) {
 887                         kfree(concat);
 888                         printk
 889                             ("memory allocation error while creating erase region list"
 890                              " for device \"%s\"\n", name);
 891                         return NULL;
 892                 }
 893
 894                 /*
 895                  * walk the map of the new device once more and fill in
 896                  * in erase region info:
 897                  */
 898                 curr_erasesize = subdev[0]->erasesize;
 899                 begin = position = 0;
 900                 for (i = 0; i < num_devs; i++) {
 901                         if (subdev[i]->numeraseregions == 0) {
 902                                 /* current subdevice has uniform erase size */
 903                                 if (subdev[i]->erasesize != curr_erasesize) {
 904                                         /*
 905                                          *  fill in an mtd_erase_region_info structure for the area
 906                                          *  we have walked so far:
 907                                          */
 908                                         erase_region_p->offset = begin;
 909                                         erase_region_p->erasesize =
 910                                             curr_erasesize;
 911                                         tmp64 = position - begin;
 912                                         do_div(tmp64, curr_erasesize);
 913                                         erase_region_p->numblocks = tmp64;
 914                                         begin = position;
 915
 916                                         curr_erasesize = subdev[i]->erasesize;
 917                                         ++erase_region_p;
 918                                 }
 919                                 position += subdev[i]->size;
 920                         } else {
 921                                 /* current subdevice has variable erase size */
 922                                 int j;
 923                                 for (j = 0; j < subdev[i]->numeraseregions; j++) {
 924                                         /* walk the list of erase regions, count any changes */
 925                                         if (subdev[i]->eraseregions[j].
 926                                             erasesize != curr_erasesize) {
 927                                                 erase_region_p->offset = begin;
 928                                                 erase_region_p->erasesize =
 929                                                     curr_erasesize;
 930                                                 tmp64 = position - begin;
 931                                                 do_div(tmp64, curr_erasesize);
 932                                                 erase_region_p->numblocks = tmp64;
 933                                                 begin = position;
 934
 935                                                 curr_erasesize =
 936                                                     subdev[i]->eraseregions[j].
 937                                                     erasesize;
 938                                                 ++erase_region_p;
 939                                         }
 940                                         position +=
 941                                             subdev[i]->eraseregions[j].
 942                                             numblocks * (uint64_t)curr_erasesize;
 943                                 }
 944                         }
 945                 }
 946                 /* Now write the final entry */
 947                 erase_region_p->offset = begin;
 948                 erase_region_p->erasesize = curr_erasesize;
 949                 tmp64 = position - begin;
 950                 do_div(tmp64, curr_erasesize);
 951                 erase_region_p->numblocks = tmp64;
 952         }
 953
 954         return &concat->mtd;
 955 }
 956
 957 /*
 958  * This function destroys an MTD object obtained from concat_mtd_devs()
 959  */
 960
 961 void mtd_concat_destroy(struct mtd_info *mtd)
 962 {
 963         struct mtd_concat *concat = CONCAT(mtd);
 964         if (concat->mtd.numeraseregions)
 965                 kfree(concat->mtd.eraseregions);
 966         kfree(concat);
 967 }
 968
 969 EXPORT_SYMBOL(mtd_concat_create);
 970 EXPORT_SYMBOL(mtd_concat_destroy);
 971
 972 MODULE_LICENSE("GPL");
 973 MODULE_AUTHOR("Robert Kaiser <rkaiser@sysgo.de>");
 974 MODULE_DESCRIPTION("Generic support for concatenating of MTD devices");