git.oblomov.eu Git - linux-2.6/blob - drivers/mtd/nftlmount.c

   1 /*
   2  * NFTL mount code with extensive checks
   3  *
   4  * Author: Fabrice Bellard (fabrice.bellard@netgem.com)
   5  * Copyright (C) 2000 Netgem S.A.
   6  *
   7  * $Id: nftlmount.c,v 1.40 2004/11/22 14:38:29 kalev Exp $
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22  */
  23
  24 #include <linux/kernel.h>
  25 #include <asm/errno.h>
  26 #include <linux/delay.h>
  27 #include <linux/slab.h>
  28 #include <linux/mtd/mtd.h>
  29 #include <linux/mtd/nand.h>
  30 #include <linux/mtd/nftl.h>
  31
  32 #define SECTORSIZE 512
  33
  34 char nftlmountrev[]="$Revision: 1.40 $";
  35
  36 /* find_boot_record: Find the NFTL Media Header and its Spare copy which contains the
  37  *      various device information of the NFTL partition and Bad Unit Table. Update
  38  *      the ReplUnitTable[] table accroding to the Bad Unit Table. ReplUnitTable[]
  39  *      is used for management of Erase Unit in other routines in nftl.c and nftlmount.c
  40  */
  41 static int find_boot_record(struct NFTLrecord *nftl)
  42 {
  43         struct nftl_uci1 h1;
  44         unsigned int block, boot_record_count = 0;
  45         size_t retlen;
  46         u8 buf[SECTORSIZE];
  47         struct NFTLMediaHeader *mh = &nftl->MediaHdr;
  48         unsigned int i;
  49
  50         /* Assume logical EraseSize == physical erasesize for starting the scan.
  51            We'll sort it out later if we find a MediaHeader which says otherwise */
  52         /* Actually, we won't.  The new DiskOnChip driver has already scanned
  53            the MediaHeader and adjusted the virtual erasesize it presents in
  54            the mtd device accordingly.  We could even get rid of
  55            nftl->EraseSize if there were any point in doing so. */
  56         nftl->EraseSize = nftl->mbd.mtd->erasesize;
  57         nftl->nb_blocks = nftl->mbd.mtd->size / nftl->EraseSize;
  58
  59         nftl->MediaUnit = BLOCK_NIL;
  60         nftl->SpareMediaUnit = BLOCK_NIL;
  61
  62         /* search for a valid boot record */
  63         for (block = 0; block < nftl->nb_blocks; block++) {
  64                 int ret;
  65
  66                 /* Check for ANAND header first. Then can whinge if it's found but later
  67                    checks fail */
  68                 ret = MTD_READ(nftl->mbd.mtd, block * nftl->EraseSize, SECTORSIZE, &retlen, buf);
  69                 /* We ignore ret in case the ECC of the MediaHeader is invalid
  70                    (which is apparently acceptable) */
  71                 if (retlen != SECTORSIZE) {
  72                         static int warncount = 5;
  73
  74                         if (warncount) {
  75                                 printk(KERN_WARNING "Block read at 0x%x of mtd%d failed: %d\n",
  76                                        block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  77                                 if (!--warncount)
  78                                         printk(KERN_WARNING "Further failures for this block will not be printed\n");
  79                         }
  80                         continue;
  81                 }
  82
  83                 if (retlen < 6 || memcmp(buf, "ANAND", 6)) {
  84                         /* ANAND\0 not found. Continue */
  85 #if 0
  86                         printk(KERN_DEBUG "ANAND header not found at 0x%x in mtd%d\n",
  87                                block * nftl->EraseSize, nftl->mbd.mtd->index);
  88 #endif
  89                         continue;
  90                 }
  91
  92                 /* To be safer with BIOS, also use erase mark as discriminant */
  93                 if ((ret = MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + SECTORSIZE + 8,
  94                                 8, &retlen, (char *)&h1) < 0)) {
  95                         printk(KERN_WARNING "ANAND header found at 0x%x in mtd%d, but OOB data read failed (err %d)\n",
  96                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
  97                         continue;
  98                 }
  99
 100 #if 0 /* Some people seem to have devices without ECC or erase marks
 101          on the Media Header blocks. There are enough other sanity
 102          checks in here that we can probably do without it.
 103       */
 104                 if (le16_to_cpu(h1.EraseMark | h1.EraseMark1) != ERASE_MARK) {
 105                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but erase mark not present (0x%04x,0x%04x instead)\n",
 106                                block * nftl->EraseSize, nftl->mbd.mtd->index,
 107                                le16_to_cpu(h1.EraseMark), le16_to_cpu(h1.EraseMark1));
 108                         continue;
 109                 }
 110
 111                 /* Finally reread to check ECC */
 112                 if ((ret = MTD_READECC(nftl->mbd.mtd, block * nftl->EraseSize, SECTORSIZE,
 113                                 &retlen, buf, (char *)&oob, NULL) < 0)) {
 114                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but ECC read failed (err %d)\n",
 115                                block * nftl->EraseSize, nftl->mbd.mtd->index, ret);
 116                         continue;
 117                 }
 118
 119                 /* Paranoia. Check the ANAND header is still there after the ECC read */
 120                 if (memcmp(buf, "ANAND", 6)) {
 121                         printk(KERN_NOTICE "ANAND header found at 0x%x in mtd%d, but went away on reread!\n",
 122                                block * nftl->EraseSize, nftl->mbd.mtd->index);
 123                         printk(KERN_NOTICE "New data are: %02x %02x %02x %02x %02x %02x\n",
 124                                buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
 125                         continue;
 126                 }
 127 #endif
 128                 /* OK, we like it. */
 129
 130                 if (boot_record_count) {
 131                         /* We've already processed one. So we just check if
 132                            this one is the same as the first one we found */
 133                         if (memcmp(mh, buf, sizeof(struct NFTLMediaHeader))) {
 134                                 printk(KERN_NOTICE "NFTL Media Headers at 0x%x and 0x%x disagree.\n",
 135                                        nftl->MediaUnit * nftl->EraseSize, block * nftl->EraseSize);
 136                                 /* if (debug) Print both side by side */
 137                                 if (boot_record_count < 2) {
 138                                         /* We haven't yet seen two real ones */
 139                                         return -1;
 140                                 }
 141                                 continue;
 142                         }
 143                         if (boot_record_count == 1)
 144                                 nftl->SpareMediaUnit = block;
 145
 146                         /* Mark this boot record (NFTL MediaHeader) block as reserved */
 147                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 148
 149
 150                         boot_record_count++;
 151                         continue;
 152                 }
 153
 154                 /* This is the first we've seen. Copy the media header structure into place */
 155                 memcpy(mh, buf, sizeof(struct NFTLMediaHeader));
 156
 157                 /* Do some sanity checks on it */
 158 #if 0
 159 The new DiskOnChip driver scans the MediaHeader itself, and presents a virtual
 160 erasesize based on UnitSizeFactor.  So the erasesize we read from the mtd
 161 device is already correct.
 162                 if (mh->UnitSizeFactor == 0) {
 163                         printk(KERN_NOTICE "NFTL: UnitSizeFactor 0x00 detected. This violates the spec but we think we know what it means...\n");
 164                 } else if (mh->UnitSizeFactor < 0xfc) {
 165                         printk(KERN_NOTICE "Sorry, we don't support UnitSizeFactor 0x%02x\n",
 166                                mh->UnitSizeFactor);
 167                         return -1;
 168                 } else if (mh->UnitSizeFactor != 0xff) {
 169                         printk(KERN_NOTICE "WARNING: Support for NFTL with UnitSizeFactor 0x%02x is experimental\n",
 170                                mh->UnitSizeFactor);
 171                         nftl->EraseSize = nftl->mbd.mtd->erasesize << (0xff - mh->UnitSizeFactor);
 172                         nftl->nb_blocks = nftl->mbd.mtd->size / nftl->EraseSize;
 173                 }
 174 #endif
 175                 nftl->nb_boot_blocks = le16_to_cpu(mh->FirstPhysicalEUN);
 176                 if ((nftl->nb_boot_blocks + 2) >= nftl->nb_blocks) {
 177                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 178                         printk(KERN_NOTICE "nb_boot_blocks (%d) + 2 > nb_blocks (%d)\n",
 179                                nftl->nb_boot_blocks, nftl->nb_blocks);
 180                         return -1;
 181                 }
 182
 183                 nftl->numvunits = le32_to_cpu(mh->FormattedSize) / nftl->EraseSize;
 184                 if (nftl->numvunits > (nftl->nb_blocks - nftl->nb_boot_blocks - 2)) {
 185                         printk(KERN_NOTICE "NFTL Media Header sanity check failed:\n");
 186                         printk(KERN_NOTICE "numvunits (%d) > nb_blocks (%d) - nb_boot_blocks(%d) - 2\n",
 187                                nftl->numvunits, nftl->nb_blocks, nftl->nb_boot_blocks);
 188                         return -1;
 189                 }
 190
 191                 nftl->mbd.size  = nftl->numvunits * (nftl->EraseSize / SECTORSIZE);
 192
 193                 /* If we're not using the last sectors in the device for some reason,
 194                    reduce nb_blocks accordingly so we forget they're there */
 195                 nftl->nb_blocks = le16_to_cpu(mh->NumEraseUnits) + le16_to_cpu(mh->FirstPhysicalEUN);
 196
 197                 /* XXX: will be suppressed */
 198                 nftl->lastEUN = nftl->nb_blocks - 1;
 199
 200                 /* memory alloc */
 201                 nftl->EUNtable = kmalloc(nftl->nb_blocks * sizeof(u16), GFP_KERNEL);
 202                 if (!nftl->EUNtable) {
 203                         printk(KERN_NOTICE "NFTL: allocation of EUNtable failed\n");
 204                         return -ENOMEM;
 205                 }
 206
 207                 nftl->ReplUnitTable = kmalloc(nftl->nb_blocks * sizeof(u16), GFP_KERNEL);
 208                 if (!nftl->ReplUnitTable) {
 209                         kfree(nftl->EUNtable);
 210                         printk(KERN_NOTICE "NFTL: allocation of ReplUnitTable failed\n");
 211                         return -ENOMEM;
 212                 }
 213
 214                 /* mark the bios blocks (blocks before NFTL MediaHeader) as reserved */
 215                 for (i = 0; i < nftl->nb_boot_blocks; i++)
 216                         nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 217                 /* mark all remaining blocks as potentially containing data */
 218                 for (; i < nftl->nb_blocks; i++) {
 219                         nftl->ReplUnitTable[i] = BLOCK_NOTEXPLORED;
 220                 }
 221
 222                 /* Mark this boot record (NFTL MediaHeader) block as reserved */
 223                 nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 224
 225                 /* read the Bad Erase Unit Table and modify ReplUnitTable[] accordingly */
 226                 for (i = 0; i < nftl->nb_blocks; i++) {
 227 #if 0
 228 The new DiskOnChip driver already scanned the bad block table.  Just query it.
 229                         if ((i & (SECTORSIZE - 1)) == 0) {
 230                                 /* read one sector for every SECTORSIZE of blocks */
 231                                 if ((ret = MTD_READECC(nftl->mbd.mtd, block * nftl->EraseSize +
 232                                                        i + SECTORSIZE, SECTORSIZE, &retlen, buf,
 233                                                        (char *)&oob, NULL)) < 0) {
 234                                         printk(KERN_NOTICE "Read of bad sector table failed (err %d)\n",
 235                                                ret);
 236                                         kfree(nftl->ReplUnitTable);
 237                                         kfree(nftl->EUNtable);
 238                                         return -1;
 239                                 }
 240                         }
 241                         /* mark the Bad Erase Unit as RESERVED in ReplUnitTable */
 242                         if (buf[i & (SECTORSIZE - 1)] != 0xff)
 243                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 244 #endif
 245                         if (nftl->mbd.mtd->block_isbad(nftl->mbd.mtd, i * nftl->EraseSize))
 246                                 nftl->ReplUnitTable[i] = BLOCK_RESERVED;
 247                 }
 248
 249                 nftl->MediaUnit = block;
 250                 boot_record_count++;
 251
 252         } /* foreach (block) */
 253
 254         return boot_record_count?0:-1;
 255 }
 256
 257 static int memcmpb(void *a, int c, int n)
 258 {
 259         int i;
 260         for (i = 0; i < n; i++) {
 261                 if (c != ((unsigned char *)a)[i])
 262                         return 1;
 263         }
 264         return 0;
 265 }
 266
 267 /* check_free_sector: check if a free sector is actually FREE, i.e. All 0xff in data and oob area */
 268 static int check_free_sectors(struct NFTLrecord *nftl, unsigned int address, int len,
 269                               int check_oob)
 270 {
 271         int i;
 272         size_t retlen;
 273         u8 buf[SECTORSIZE + nftl->mbd.mtd->oobsize];
 274
 275         for (i = 0; i < len; i += SECTORSIZE) {
 276                 if (MTD_READECC(nftl->mbd.mtd, address, SECTORSIZE, &retlen, buf, &buf[SECTORSIZE], &nftl->oobinfo) < 0)
 277                         return -1;
 278                 if (memcmpb(buf, 0xff, SECTORSIZE) != 0)
 279                         return -1;
 280
 281                 if (check_oob) {
 282                         if (memcmpb(buf + SECTORSIZE, 0xff, nftl->mbd.mtd->oobsize) != 0)
 283                                 return -1;
 284                 }
 285                 address += SECTORSIZE;
 286         }
 287
 288         return 0;
 289 }
 290
 291 /* NFTL_format: format a Erase Unit by erasing ALL Erase Zones in the Erase Unit and
 292  *              Update NFTL metadata. Each erase operation is checked with check_free_sectors
 293  *
 294  * Return: 0 when succeed, -1 on error.
 295  *
 296  *  ToDo: 1. Is it neceressary to check_free_sector after erasing ??
 297  */
 298 int NFTL_formatblock(struct NFTLrecord *nftl, int block)
 299 {
 300         size_t retlen;
 301         unsigned int nb_erases, erase_mark;
 302         struct nftl_uci1 uci;
 303         struct erase_info *instr = &nftl->instr;
 304
 305         /* Read the Unit Control Information #1 for Wear-Leveling */
 306         if (MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + SECTORSIZE + 8,
 307                         8, &retlen, (char *)&uci) < 0)
 308                 goto default_uci1;
 309
 310         erase_mark = le16_to_cpu ((uci.EraseMark | uci.EraseMark1));
 311         if (erase_mark != ERASE_MARK) {
 312         default_uci1:
 313                 uci.EraseMark = cpu_to_le16(ERASE_MARK);
 314                 uci.EraseMark1 = cpu_to_le16(ERASE_MARK);
 315                 uci.WearInfo = cpu_to_le32(0);
 316         }
 317
 318         memset(instr, 0, sizeof(struct erase_info));
 319
 320         /* XXX: use async erase interface, XXX: test return code */
 321         instr->mtd = nftl->mbd.mtd;
 322         instr->addr = block * nftl->EraseSize;
 323         instr->len = nftl->EraseSize;
 324         MTD_ERASE(nftl->mbd.mtd, instr);
 325
 326         if (instr->state == MTD_ERASE_FAILED) {
 327                 printk("Error while formatting block %d\n", block);
 328                 goto fail;
 329         }
 330
 331                 /* increase and write Wear-Leveling info */
 332                 nb_erases = le32_to_cpu(uci.WearInfo);
 333                 nb_erases++;
 334
 335                 /* wrap (almost impossible with current flashs) or free block */
 336                 if (nb_erases == 0)
 337                         nb_erases = 1;
 338
 339                 /* check the "freeness" of Erase Unit before updating metadata
 340                  * FixMe:  is this check really necessary ? since we have check the
 341                  *         return code after the erase operation. */
 342                 if (check_free_sectors(nftl, instr->addr, nftl->EraseSize, 1) != 0)
 343                         goto fail;
 344
 345                 uci.WearInfo = le32_to_cpu(nb_erases);
 346                 if (MTD_WRITEOOB(nftl->mbd.mtd, block * nftl->EraseSize + SECTORSIZE + 8, 8,
 347                                  &retlen, (char *)&uci) < 0)
 348                         goto fail;
 349                 return 0;
 350 fail:
 351         /* could not format, update the bad block table (caller is responsible
 352            for setting the ReplUnitTable to BLOCK_RESERVED on failure) */
 353         nftl->mbd.mtd->block_markbad(nftl->mbd.mtd, instr->addr);
 354         return -1;
 355 }
 356
 357 /* check_sectors_in_chain: Check that each sector of a Virtual Unit Chain is correct.
 358  *      Mark as 'IGNORE' each incorrect sector. This check is only done if the chain
 359  *      was being folded when NFTL was interrupted.
 360  *
 361  *      The check_free_sectors in this function is neceressary. There is a possible
 362  *      situation that after writing the Data area, the Block Control Information is
 363  *      not updated according (due to power failure or something) which leaves the block
 364  *      in an umconsistent state. So we have to check if a block is really FREE in this
 365  *      case. */
 366 static void check_sectors_in_chain(struct NFTLrecord *nftl, unsigned int first_block)
 367 {
 368         unsigned int block, i, status;
 369         struct nftl_bci bci;
 370         int sectors_per_block;
 371         size_t retlen;
 372
 373         sectors_per_block = nftl->EraseSize / SECTORSIZE;
 374         block = first_block;
 375         for (;;) {
 376                 for (i = 0; i < sectors_per_block; i++) {
 377                         if (MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + i * SECTORSIZE,
 378                                         8, &retlen, (char *)&bci) < 0)
 379                                 status = SECTOR_IGNORE;
 380                         else
 381                                 status = bci.Status | bci.Status1;
 382
 383                         switch(status) {
 384                         case SECTOR_FREE:
 385                                 /* verify that the sector is really free. If not, mark
 386                                    as ignore */
 387                                 if (memcmpb(&bci, 0xff, 8) != 0 ||
 388                                     check_free_sectors(nftl, block * nftl->EraseSize + i * SECTORSIZE,
 389                                                        SECTORSIZE, 0) != 0) {
 390                                         printk("Incorrect free sector %d in block %d: "
 391                                                "marking it as ignored\n",
 392                                                i, block);
 393
 394                                         /* sector not free actually : mark it as SECTOR_IGNORE  */
 395                                         bci.Status = SECTOR_IGNORE;
 396                                         bci.Status1 = SECTOR_IGNORE;
 397                                         MTD_WRITEOOB(nftl->mbd.mtd,
 398                                                      block * nftl->EraseSize + i * SECTORSIZE,
 399                                                      8, &retlen, (char *)&bci);
 400                                 }
 401                                 break;
 402                         default:
 403                                 break;
 404                         }
 405                 }
 406
 407                 /* proceed to next Erase Unit on the chain */
 408                 block = nftl->ReplUnitTable[block];
 409                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 410                         printk("incorrect ReplUnitTable[] : %d\n", block);
 411                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 412                         break;
 413         }
 414 }
 415
 416 /* calc_chain_lenght: Walk through a Virtual Unit Chain and estimate chain length */
 417 static int calc_chain_length(struct NFTLrecord *nftl, unsigned int first_block)
 418 {
 419         unsigned int length = 0, block = first_block;
 420
 421         for (;;) {
 422                 length++;
 423                 /* avoid infinite loops, although this is guaranted not to
 424                    happen because of the previous checks */
 425                 if (length >= nftl->nb_blocks) {
 426                         printk("nftl: length too long %d !\n", length);
 427                         break;
 428                 }
 429
 430                 block = nftl->ReplUnitTable[block];
 431                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 432                         printk("incorrect ReplUnitTable[] : %d\n", block);
 433                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 434                         break;
 435         }
 436         return length;
 437 }
 438
 439 /* format_chain: Format an invalid Virtual Unit chain. It frees all the Erase Units in a
 440  *      Virtual Unit Chain, i.e. all the units are disconnected.
 441  *
 442  *      It is not stricly correct to begin from the first block of the chain because
 443  *      if we stop the code, we may see again a valid chain if there was a first_block
 444  *      flag in a block inside it. But is it really a problem ?
 445  *
 446  * FixMe: Figure out what the last statesment means. What if power failure when we are
 447  *      in the for (;;) loop formatting blocks ??
 448  */
 449 static void format_chain(struct NFTLrecord *nftl, unsigned int first_block)
 450 {
 451         unsigned int block = first_block, block1;
 452
 453         printk("Formatting chain at block %d\n", first_block);
 454
 455         for (;;) {
 456                 block1 = nftl->ReplUnitTable[block];
 457
 458                 printk("Formatting block %d\n", block);
 459                 if (NFTL_formatblock(nftl, block) < 0) {
 460                         /* cannot format !!!! Mark it as Bad Unit */
 461                         nftl->ReplUnitTable[block] = BLOCK_RESERVED;
 462                 } else {
 463                         nftl->ReplUnitTable[block] = BLOCK_FREE;
 464                 }
 465
 466                 /* goto next block on the chain */
 467                 block = block1;
 468
 469                 if (!(block == BLOCK_NIL || block < nftl->nb_blocks))
 470                         printk("incorrect ReplUnitTable[] : %d\n", block);
 471                 if (block == BLOCK_NIL || block >= nftl->nb_blocks)
 472                         break;
 473         }
 474 }
 475
 476 /* check_and_mark_free_block: Verify that a block is free in the NFTL sense (valid erase mark) or
 477  *      totally free (only 0xff).
 478  *
 479  * Definition: Free Erase Unit -- A properly erased/formatted Free Erase Unit should have meet the
 480  *      following critia:
 481  *      1. */
 482 static int check_and_mark_free_block(struct NFTLrecord *nftl, int block)
 483 {
 484         struct nftl_uci1 h1;
 485         unsigned int erase_mark;
 486         size_t retlen;
 487
 488         /* check erase mark. */
 489         if (MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + SECTORSIZE + 8, 8,
 490                         &retlen, (char *)&h1) < 0)
 491                 return -1;
 492
 493         erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 494         if (erase_mark != ERASE_MARK) {
 495                 /* if no erase mark, the block must be totally free. This is
 496                    possible in two cases : empty filsystem or interrupted erase (very unlikely) */
 497                 if (check_free_sectors (nftl, block * nftl->EraseSize, nftl->EraseSize, 1) != 0)
 498                         return -1;
 499
 500                 /* free block : write erase mark */
 501                 h1.EraseMark = cpu_to_le16(ERASE_MARK);
 502                 h1.EraseMark1 = cpu_to_le16(ERASE_MARK);
 503                 h1.WearInfo = cpu_to_le32(0);
 504                 if (MTD_WRITEOOB(nftl->mbd.mtd, block * nftl->EraseSize + SECTORSIZE + 8, 8,
 505                                  &retlen, (char *)&h1) < 0)
 506                         return -1;
 507         } else {
 508 #if 0
 509                 /* if erase mark present, need to skip it when doing check */
 510                 for (i = 0; i < nftl->EraseSize; i += SECTORSIZE) {
 511                         /* check free sector */
 512                         if (check_free_sectors (nftl, block * nftl->EraseSize + i,
 513                                                 SECTORSIZE, 0) != 0)
 514                                 return -1;
 515
 516                         if (MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + i,
 517                                         16, &retlen, buf) < 0)
 518                                 return -1;
 519                         if (i == SECTORSIZE) {
 520                                 /* skip erase mark */
 521                                 if (memcmpb(buf, 0xff, 8))
 522                                         return -1;
 523                         } else {
 524                                 if (memcmpb(buf, 0xff, 16))
 525                                         return -1;
 526                         }
 527                 }
 528 #endif
 529         }
 530
 531         return 0;
 532 }
 533
 534 /* get_fold_mark: Read fold mark from Unit Control Information #2, we use FOLD_MARK_IN_PROGRESS
 535  *      to indicate that we are in the progression of a Virtual Unit Chain folding. If the UCI #2
 536  *      is FOLD_MARK_IN_PROGRESS when mounting the NFTL, the (previous) folding process is interrupted
 537  *      for some reason. A clean up/check of the VUC is neceressary in this case.
 538  *
 539  * WARNING: return 0 if read error
 540  */
 541 static int get_fold_mark(struct NFTLrecord *nftl, unsigned int block)
 542 {
 543         struct nftl_uci2 uci;
 544         size_t retlen;
 545
 546         if (MTD_READOOB(nftl->mbd.mtd, block * nftl->EraseSize + 2 * SECTORSIZE + 8,
 547                         8, &retlen, (char *)&uci) < 0)
 548                 return 0;
 549
 550         return le16_to_cpu((uci.FoldMark | uci.FoldMark1));
 551 }
 552
 553 int NFTL_mount(struct NFTLrecord *s)
 554 {
 555         int i;
 556         unsigned int first_logical_block, logical_block, rep_block, nb_erases, erase_mark;
 557         unsigned int block, first_block, is_first_block;
 558         int chain_length, do_format_chain;
 559         struct nftl_uci0 h0;
 560         struct nftl_uci1 h1;
 561         size_t retlen;
 562
 563         /* search for NFTL MediaHeader and Spare NFTL Media Header */
 564         if (find_boot_record(s) < 0) {
 565                 printk("Could not find valid boot record\n");
 566                 return -1;
 567         }
 568
 569         /* init the logical to physical table */
 570         for (i = 0; i < s->nb_blocks; i++) {
 571                 s->EUNtable[i] = BLOCK_NIL;
 572         }
 573
 574         /* first pass : explore each block chain */
 575         first_logical_block = 0;
 576         for (first_block = 0; first_block < s->nb_blocks; first_block++) {
 577                 /* if the block was not already explored, we can look at it */
 578                 if (s->ReplUnitTable[first_block] == BLOCK_NOTEXPLORED) {
 579                         block = first_block;
 580                         chain_length = 0;
 581                         do_format_chain = 0;
 582
 583                         for (;;) {
 584                                 /* read the block header. If error, we format the chain */
 585                                 if (MTD_READOOB(s->mbd.mtd, block * s->EraseSize + 8, 8,
 586                                                 &retlen, (char *)&h0) < 0 ||
 587                                     MTD_READOOB(s->mbd.mtd, block * s->EraseSize + SECTORSIZE + 8, 8,
 588                                                 &retlen, (char *)&h1) < 0) {
 589                                         s->ReplUnitTable[block] = BLOCK_NIL;
 590                                         do_format_chain = 1;
 591                                         break;
 592                                 }
 593
 594                                 logical_block = le16_to_cpu ((h0.VirtUnitNum | h0.SpareVirtUnitNum));
 595                                 rep_block = le16_to_cpu ((h0.ReplUnitNum | h0.SpareReplUnitNum));
 596                                 nb_erases = le32_to_cpu (h1.WearInfo);
 597                                 erase_mark = le16_to_cpu ((h1.EraseMark | h1.EraseMark1));
 598
 599                                 is_first_block = !(logical_block >> 15);
 600                                 logical_block = logical_block & 0x7fff;
 601
 602                                 /* invalid/free block test */
 603                                 if (erase_mark != ERASE_MARK || logical_block >= s->nb_blocks) {
 604                                         if (chain_length == 0) {
 605                                                 /* if not currently in a chain, we can handle it safely */
 606                                                 if (check_and_mark_free_block(s, block) < 0) {
 607                                                         /* not really free: format it */
 608                                                         printk("Formatting block %d\n", block);
 609                                                         if (NFTL_formatblock(s, block) < 0) {
 610                                                                 /* could not format: reserve the block */
 611                                                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 612                                                         } else {
 613                                                                 s->ReplUnitTable[block] = BLOCK_FREE;
 614                                                         }
 615                                                 } else {
 616                                                         /* free block: mark it */
 617                                                         s->ReplUnitTable[block] = BLOCK_FREE;
 618                                                 }
 619                                                 /* directly examine the next block. */
 620                                                 goto examine_ReplUnitTable;
 621                                         } else {
 622                                                 /* the block was in a chain : this is bad. We
 623                                                    must format all the chain */
 624                                                 printk("Block %d: free but referenced in chain %d\n",
 625                                                        block, first_block);
 626                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 627                                                 do_format_chain = 1;
 628                                                 break;
 629                                         }
 630                                 }
 631
 632                                 /* we accept only first blocks here */
 633                                 if (chain_length == 0) {
 634                                         /* this block is not the first block in chain :
 635                                            ignore it, it will be included in a chain
 636                                            later, or marked as not explored */
 637                                         if (!is_first_block)
 638                                                 goto examine_ReplUnitTable;
 639                                         first_logical_block = logical_block;
 640                                 } else {
 641                                         if (logical_block != first_logical_block) {
 642                                                 printk("Block %d: incorrect logical block: %d expected: %d\n",
 643                                                        block, logical_block, first_logical_block);
 644                                                 /* the chain is incorrect : we must format it,
 645                                                    but we need to read it completly */
 646                                                 do_format_chain = 1;
 647                                         }
 648                                         if (is_first_block) {
 649                                                 /* we accept that a block is marked as first
 650                                                    block while being last block in a chain
 651                                                    only if the chain is being folded */
 652                                                 if (get_fold_mark(s, block) != FOLD_MARK_IN_PROGRESS ||
 653                                                     rep_block != 0xffff) {
 654                                                         printk("Block %d: incorrectly marked as first block in chain\n",
 655                                                                block);
 656                                                         /* the chain is incorrect : we must format it,
 657                                                            but we need to read it completly */
 658                                                         do_format_chain = 1;
 659                                                 } else {
 660                                                         printk("Block %d: folding in progress - ignoring first block flag\n",
 661                                                                block);
 662                                                 }
 663                                         }
 664                                 }
 665                                 chain_length++;
 666                                 if (rep_block == 0xffff) {
 667                                         /* no more blocks after */
 668                                         s->ReplUnitTable[block] = BLOCK_NIL;
 669                                         break;
 670                                 } else if (rep_block >= s->nb_blocks) {
 671                                         printk("Block %d: referencing invalid block %d\n",
 672                                                block, rep_block);
 673                                         do_format_chain = 1;
 674                                         s->ReplUnitTable[block] = BLOCK_NIL;
 675                                         break;
 676                                 } else if (s->ReplUnitTable[rep_block] != BLOCK_NOTEXPLORED) {
 677                                         /* same problem as previous 'is_first_block' test:
 678                                            we accept that the last block of a chain has
 679                                            the first_block flag set if folding is in
 680                                            progress. We handle here the case where the
 681                                            last block appeared first */
 682                                         if (s->ReplUnitTable[rep_block] == BLOCK_NIL &&
 683                                             s->EUNtable[first_logical_block] == rep_block &&
 684                                             get_fold_mark(s, first_block) == FOLD_MARK_IN_PROGRESS) {
 685                                                 /* EUNtable[] will be set after */
 686                                                 printk("Block %d: folding in progress - ignoring first block flag\n",
 687                                                        rep_block);
 688                                                 s->ReplUnitTable[block] = rep_block;
 689                                                 s->EUNtable[first_logical_block] = BLOCK_NIL;
 690                                         } else {
 691                                                 printk("Block %d: referencing block %d already in another chain\n",
 692                                                        block, rep_block);
 693                                                 /* XXX: should handle correctly fold in progress chains */
 694                                                 do_format_chain = 1;
 695                                                 s->ReplUnitTable[block] = BLOCK_NIL;
 696                                         }
 697                                         break;
 698                                 } else {
 699                                         /* this is OK */
 700                                         s->ReplUnitTable[block] = rep_block;
 701                                         block = rep_block;
 702                                 }
 703                         }
 704
 705                         /* the chain was completely explored. Now we can decide
 706                            what to do with it */
 707                         if (do_format_chain) {
 708                                 /* invalid chain : format it */
 709                                 format_chain(s, first_block);
 710                         } else {
 711                                 unsigned int first_block1, chain_to_format, chain_length1;
 712                                 int fold_mark;
 713
 714                                 /* valid chain : get foldmark */
 715                                 fold_mark = get_fold_mark(s, first_block);
 716                                 if (fold_mark == 0) {
 717                                         /* cannot get foldmark : format the chain */
 718                                         printk("Could read foldmark at block %d\n", first_block);
 719                                         format_chain(s, first_block);
 720                                 } else {
 721                                         if (fold_mark == FOLD_MARK_IN_PROGRESS)
 722                                                 check_sectors_in_chain(s, first_block);
 723
 724                                         /* now handle the case where we find two chains at the
 725                                            same virtual address : we select the longer one,
 726                                            because the shorter one is the one which was being
 727                                            folded if the folding was not done in place */
 728                                         first_block1 = s->EUNtable[first_logical_block];
 729                                         if (first_block1 != BLOCK_NIL) {
 730                                                 /* XXX: what to do if same length ? */
 731                                                 chain_length1 = calc_chain_length(s, first_block1);
 732                                                 printk("Two chains at blocks %d (len=%d) and %d (len=%d)\n",
 733                                                        first_block1, chain_length1, first_block, chain_length);
 734
 735                                                 if (chain_length >= chain_length1) {
 736                                                         chain_to_format = first_block1;
 737                                                         s->EUNtable[first_logical_block] = first_block;
 738                                                 } else {
 739                                                         chain_to_format = first_block;
 740                                                 }
 741                                                 format_chain(s, chain_to_format);
 742                                         } else {
 743                                                 s->EUNtable[first_logical_block] = first_block;
 744                                         }
 745                                 }
 746                         }
 747                 }
 748         examine_ReplUnitTable:;
 749         }
 750
 751         /* second pass to format unreferenced blocks  and init free block count */
 752         s->numfreeEUNs = 0;
 753         s->LastFreeEUN = le16_to_cpu(s->MediaHdr.FirstPhysicalEUN);
 754
 755         for (block = 0; block < s->nb_blocks; block++) {
 756                 if (s->ReplUnitTable[block] == BLOCK_NOTEXPLORED) {
 757                         printk("Unreferenced block %d, formatting it\n", block);
 758                         if (NFTL_formatblock(s, block) < 0)
 759                                 s->ReplUnitTable[block] = BLOCK_RESERVED;
 760                         else
 761                                 s->ReplUnitTable[block] = BLOCK_FREE;
 762                 }
 763                 if (s->ReplUnitTable[block] == BLOCK_FREE) {
 764                         s->numfreeEUNs++;
 765                         s->LastFreeEUN = block;
 766                 }
 767         }
 768
 769         return 0;
 770 }