drivers/mtd/inftlcore.c

   1 /*
   2  * inftlcore.c -- Linux driver for Inverse Flash Translation Layer (INFTL)
   3  *
   4  * (C) Copyright 2002, Greg Ungerer (gerg@snapgear.com)
   5  *
   6  * Based heavily on the nftlcore.c code which is:
   7  * (c) 1999 Machine Vision Holdings, Inc.
   8  * Author: David Woodhouse <dwmw2@infradead.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/module.h>
  27 #include <linux/delay.h>
  28 #include <linux/slab.h>
  29 #include <linux/sched.h>
  30 #include <linux/init.h>
  31 #include <linux/kmod.h>
  32 #include <linux/hdreg.h>
  33 #include <linux/mtd/mtd.h>
  34 #include <linux/mtd/nftl.h>
  35 #include <linux/mtd/inftl.h>
  36 #include <linux/mtd/nand.h>
  37 #include <asm/uaccess.h>
  38 #include <asm/errno.h>
  39 #include <asm/io.h>
  40
  41 /*
  42  * Maximum number of loops while examining next block, to have a
  43  * chance to detect consistency problems (they should never happen
  44  * because of the checks done in the mounting.
  45  */
  46 #define MAX_LOOPS 10000
  47
  48 static void inftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  49 {
  50         struct INFTLrecord *inftl;
  51         unsigned long temp;
  52
  53         if (mtd->type != MTD_NANDFLASH || mtd->size > UINT_MAX)
  54                 return;
  55         /* OK, this is moderately ugly.  But probably safe.  Alternatives? */
  56         if (memcmp(mtd->name, "DiskOnChip", 10))
  57                 return;
  58
  59         if (!mtd->block_isbad) {
  60                 printk(KERN_ERR
  61 "INFTL no longer supports the old DiskOnChip drivers loaded via docprobe.\n"
  62 "Please use the new diskonchip driver under the NAND subsystem.\n");
  63                 return;
  64         }
  65
  66         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: add_mtd for %s\n", mtd->name);
  67
  68         inftl = kzalloc(sizeof(*inftl), GFP_KERNEL);
  69
  70         if (!inftl) {
  71                 printk(KERN_WARNING "INFTL: Out of memory for data structures\n");
  72                 return;
  73         }
  74
  75         inftl->mbd.mtd = mtd;
  76         inftl->mbd.devnum = -1;
  77
  78         inftl->mbd.tr = tr;
  79
  80         if (INFTL_mount(inftl) < 0) {
  81                 printk(KERN_WARNING "INFTL: could not mount device\n");
  82                 kfree(inftl);
  83                 return;
  84         }
  85
  86         /* OK, it's a new one. Set up all the data structures. */
  87
  88         /* Calculate geometry */
  89         inftl->cylinders = 1024;
  90         inftl->heads = 16;
  91
  92         temp = inftl->cylinders * inftl->heads;
  93         inftl->sectors = inftl->mbd.size / temp;
  94         if (inftl->mbd.size % temp) {
  95                 inftl->sectors++;
  96                 temp = inftl->cylinders * inftl->sectors;
  97                 inftl->heads = inftl->mbd.size / temp;
  98
  99                 if (inftl->mbd.size % temp) {
 100                         inftl->heads++;
 101                         temp = inftl->heads * inftl->sectors;
 102                         inftl->cylinders = inftl->mbd.size / temp;
 103                 }
 104         }
 105
 106         if (inftl->mbd.size != inftl->heads * inftl->cylinders * inftl->sectors) {
 107                 /*
 108                   Oh no we don't have
 109                    mbd.size == heads * cylinders * sectors
 110                 */
 111                 printk(KERN_WARNING "INFTL: cannot calculate a geometry to "
 112                        "match size of 0x%lx.\n", inftl->mbd.size);
 113                 printk(KERN_WARNING "INFTL: using C:%d H:%d S:%d "
 114                         "(== 0x%lx sects)\n",
 115                         inftl->cylinders, inftl->heads , inftl->sectors,
 116                         (long)inftl->cylinders * (long)inftl->heads *
 117                         (long)inftl->sectors );
 118         }
 119
 120         if (add_mtd_blktrans_dev(&inftl->mbd)) {
 121                 kfree(inftl->PUtable);
 122                 kfree(inftl->VUtable);
 123                 kfree(inftl);
 124                 return;
 125         }
 126 #ifdef PSYCHO_DEBUG
 127         printk(KERN_INFO "INFTL: Found new inftl%c\n", inftl->mbd.devnum + 'a');
 128 #endif
 129         return;
 130 }
 131
 132 static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
 133 {
 134         struct INFTLrecord *inftl = (void *)dev;
 135
 136         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: remove_dev (i=%d)\n", dev->devnum);
 137
 138         del_mtd_blktrans_dev(dev);
 139
 140         kfree(inftl->PUtable);
 141         kfree(inftl->VUtable);
 142 }
 143
 144 /*
 145  * Actual INFTL access routines.
 146  */
 147
 148 /*
 149  * Read oob data from flash
 150  */
 151 int inftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 152                    size_t *retlen, uint8_t *buf)
 153 {
 154         struct mtd_oob_ops ops;
 155         int res;
 156
 157         ops.mode = MTD_OOB_PLACE;
 158         ops.ooboffs = offs & (mtd->writesize - 1);
 159         ops.ooblen = len;
 160         ops.oobbuf = buf;
 161         ops.datbuf = NULL;
 162
 163         res = mtd->read_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 164         *retlen = ops.oobretlen;
 165         return res;
 166 }
 167
 168 /*
 169  * Write oob data to flash
 170  */
 171 int inftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 172                     size_t *retlen, uint8_t *buf)
 173 {
 174         struct mtd_oob_ops ops;
 175         int res;
 176
 177         ops.mode = MTD_OOB_PLACE;
 178         ops.ooboffs = offs & (mtd->writesize - 1);
 179         ops.ooblen = len;
 180         ops.oobbuf = buf;
 181         ops.datbuf = NULL;
 182
 183         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 184         *retlen = ops.oobretlen;
 185         return res;
 186 }
 187
 188 /*
 189  * Write data and oob to flash
 190  */
 191 static int inftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
 192                        size_t *retlen, uint8_t *buf, uint8_t *oob)
 193 {
 194         struct mtd_oob_ops ops;
 195         int res;
 196
 197         ops.mode = MTD_OOB_PLACE;
 198         ops.ooboffs = offs;
 199         ops.ooblen = mtd->oobsize;
 200         ops.oobbuf = oob;
 201         ops.datbuf = buf;
 202         ops.len = len;
 203
 204         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 205         *retlen = ops.retlen;
 206         return res;
 207 }
 208
 209 /*
 210  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
 211  *      This function is used when the give Virtual Unit Chain.
 212  */
 213 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
 214 {
 215         u16 pot = inftl->LastFreeEUN;
 216         int silly = inftl->nb_blocks;
 217
 218         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
 219                 "desperate=%d)\n", inftl, desperate);
 220
 221         /*
 222          * Normally, we force a fold to happen before we run out of free
 223          * blocks completely.
 224          */
 225         if (!desperate && inftl->numfreeEUNs < 2) {
 226                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
 227                         "EUNs (%d)\n", inftl->numfreeEUNs);
 228                 return BLOCK_NIL;
 229         }
 230
 231         /* Scan for a free block */
 232         do {
 233                 if (inftl->PUtable[pot] == BLOCK_FREE) {
 234                         inftl->LastFreeEUN = pot;
 235                         return pot;
 236                 }
 237
 238                 if (++pot > inftl->lastEUN)
 239                         pot = 0;
 240
 241                 if (!silly--) {
 242                         printk(KERN_WARNING "INFTL: no free blocks found!  "
 243                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
 244                         return BLOCK_NIL;
 245                 }
 246         } while (pot != inftl->LastFreeEUN);
 247
 248         return BLOCK_NIL;
 249 }
 250
 251 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
 252 {
 253         u16 BlockMap[MAX_SECTORS_PER_UNIT];
 254         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 255         unsigned int thisEUN, prevEUN, status;
 256         struct mtd_info *mtd = inftl->mbd.mtd;
 257         int block, silly;
 258         unsigned int targetEUN;
 259         struct inftl_oob oob;
 260         size_t retlen;
 261
 262         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
 263                 "pending=%d)\n", inftl, thisVUC, pendingblock);
 264
 265         memset(BlockMap, 0xff, sizeof(BlockMap));
 266         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 267
 268         thisEUN = targetEUN = inftl->VUtable[thisVUC];
 269
 270         if (thisEUN == BLOCK_NIL) {
 271                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
 272                        "Virtual Unit Chain %d!\n", thisVUC);
 273                 return BLOCK_NIL;
 274         }
 275
 276         /*
 277          * Scan to find the Erase Unit which holds the actual data for each
 278          * 512-byte block within the Chain.
 279          */
 280         silly = MAX_LOOPS;
 281         while (thisEUN < inftl->nb_blocks) {
 282                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
 283                         if ((BlockMap[block] != BLOCK_NIL) ||
 284                             BlockDeleted[block])
 285                                 continue;
 286
 287                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
 288                                            + (block * SECTORSIZE), 16, &retlen,
 289                                            (char *)&oob) < 0)
 290                                 status = SECTOR_IGNORE;
 291                         else
 292                                 status = oob.b.Status | oob.b.Status1;
 293
 294                         switch(status) {
 295                         case SECTOR_FREE:
 296                         case SECTOR_IGNORE:
 297                                 break;
 298                         case SECTOR_USED:
 299                                 BlockMap[block] = thisEUN;
 300                                 continue;
 301                         case SECTOR_DELETED:
 302                                 BlockDeleted[block] = 1;
 303                                 continue;
 304                         default:
 305                                 printk(KERN_WARNING "INFTL: unknown status "
 306                                         "for block %d in EUN %d: %x\n",
 307                                         block, thisEUN, status);
 308                                 break;
 309                         }
 310                 }
 311
 312                 if (!silly--) {
 313                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 314                                 "Unit Chain 0x%x\n", thisVUC);
 315                         return BLOCK_NIL;
 316                 }
 317
 318                 thisEUN = inftl->PUtable[thisEUN];
 319         }
 320
 321         /*
 322          * OK. We now know the location of every block in the Virtual Unit
 323          * Chain, and the Erase Unit into which we are supposed to be copying.
 324          * Go for it.
 325          */
 326         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
 327                 thisVUC, targetEUN);
 328
 329         for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
 330                 unsigned char movebuf[SECTORSIZE];
 331                 int ret;
 332
 333                 /*
 334                  * If it's in the target EUN already, or if it's pending write,
 335                  * do nothing.
 336                  */
 337                 if (BlockMap[block] == targetEUN || (pendingblock ==
 338                     (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
 339                         continue;
 340                 }
 341
 342                 /*
 343                  * Copy only in non free block (free blocks can only
 344                  * happen in case of media errors or deleted blocks).
 345                  */
 346                 if (BlockMap[block] == BLOCK_NIL)
 347                         continue;
 348
 349                 ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +
 350                                 (block * SECTORSIZE), SECTORSIZE, &retlen,
 351                                 movebuf);
 352                 if (ret < 0 && ret != -EUCLEAN) {
 353                         ret = mtd->read(mtd,
 354                                         (inftl->EraseSize * BlockMap[block]) +
 355                                         (block * SECTORSIZE), SECTORSIZE,
 356                                         &retlen, movebuf);
 357                         if (ret != -EIO)
 358                                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
 359                                       "away on retry?\n");
 360                 }
 361                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 362                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 363
 364                 inftl_write(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
 365                             (block * SECTORSIZE), SECTORSIZE, &retlen,
 366                             movebuf, (char *)&oob);
 367         }
 368
 369         /*
 370          * Newest unit in chain now contains data from _all_ older units.
 371          * So go through and erase each unit in chain, oldest first. (This
 372          * is important, by doing oldest first if we crash/reboot then it
 373          * it is relatively simple to clean up the mess).
 374          */
 375         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
 376                 thisVUC);
 377
 378         for (;;) {
 379                 /* Find oldest unit in chain. */
 380                 thisEUN = inftl->VUtable[thisVUC];
 381                 prevEUN = BLOCK_NIL;
 382                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 383                         prevEUN = thisEUN;
 384                         thisEUN = inftl->PUtable[thisEUN];
 385                 }
 386
 387                 /* Check if we are all done */
 388                 if (thisEUN == targetEUN)
 389                         break;
 390
 391                 /* Unlink the last block from the chain. */
 392                 inftl->PUtable[prevEUN] = BLOCK_NIL;
 393
 394                 /* Now try to erase it. */
 395                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 396                         /*
 397                          * Could not erase : mark block as reserved.
 398                          */
 399                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 400                 } else {
 401                         /* Correctly erased : mark it as free */
 402                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 403                         inftl->numfreeEUNs++;
 404                 }
 405         }
 406
 407         return targetEUN;
 408 }
 409
 410 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
 411 {
 412         /*
 413          * This is the part that needs some cleverness applied.
 414          * For now, I'm doing the minimum applicable to actually
 415          * get the thing to work.
 416          * Wear-levelling and other clever stuff needs to be implemented
 417          * and we also need to do some assessment of the results when
 418          * the system loses power half-way through the routine.
 419          */
 420         u16 LongestChain = 0;
 421         u16 ChainLength = 0, thislen;
 422         u16 chain, EUN;
 423
 424         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
 425                 "pending=%d)\n", inftl, pendingblock);
 426
 427         for (chain = 0; chain < inftl->nb_blocks; chain++) {
 428                 EUN = inftl->VUtable[chain];
 429                 thislen = 0;
 430
 431                 while (EUN <= inftl->lastEUN) {
 432                         thislen++;
 433                         EUN = inftl->PUtable[EUN];
 434                         if (thislen > 0xff00) {
 435                                 printk(KERN_WARNING "INFTL: endless loop in "
 436                                         "Virtual Chain %d: Unit %x\n",
 437                                         chain, EUN);
 438                                 /*
 439                                  * Actually, don't return failure.
 440                                  * Just ignore this chain and get on with it.
 441                                  */
 442                                 thislen = 0;
 443                                 break;
 444                         }
 445                 }
 446
 447                 if (thislen > ChainLength) {
 448                         ChainLength = thislen;
 449                         LongestChain = chain;
 450                 }
 451         }
 452
 453         if (ChainLength < 2) {
 454                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
 455                         "for folding. Failing request\n");
 456                 return BLOCK_NIL;
 457         }
 458
 459         return INFTL_foldchain(inftl, LongestChain, pendingblock);
 460 }
 461
 462 static int nrbits(unsigned int val, int bitcount)
 463 {
 464         int i, total = 0;
 465
 466         for (i = 0; (i < bitcount); i++)
 467                 total += (((0x1 << i) & val) ? 1 : 0);
 468         return total;
 469 }
 470
 471 /*
 472  * INFTL_findwriteunit: Return the unit number into which we can write
 473  *                      for this block. Make it available if it isn't already.
 474  */
 475 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
 476 {
 477         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
 478         unsigned int thisEUN, writeEUN, prev_block, status;
 479         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
 480         struct mtd_info *mtd = inftl->mbd.mtd;
 481         struct inftl_oob oob;
 482         struct inftl_bci bci;
 483         unsigned char anac, nacs, parity;
 484         size_t retlen;
 485         int silly, silly2 = 3;
 486
 487         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
 488                 "block=%d)\n", inftl, block);
 489
 490         do {
 491                 /*
 492                  * Scan the media to find a unit in the VUC which has
 493                  * a free space for the block in question.
 494                  */
 495                 writeEUN = BLOCK_NIL;
 496                 thisEUN = inftl->VUtable[thisVUC];
 497                 silly = MAX_LOOPS;
 498
 499                 while (thisEUN <= inftl->lastEUN) {
 500                         inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 501                                        blockofs, 8, &retlen, (char *)&bci);
 502
 503                         status = bci.Status | bci.Status1;
 504                         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
 505                                 "EUN %d is %x\n", block , writeEUN, status);
 506
 507                         switch(status) {
 508                         case SECTOR_FREE:
 509                                 writeEUN = thisEUN;
 510                                 break;
 511                         case SECTOR_DELETED:
 512                         case SECTOR_USED:
 513                                 /* Can't go any further */
 514                                 goto hitused;
 515                         case SECTOR_IGNORE:
 516                                 break;
 517                         default:
 518                                 /*
 519                                  * Invalid block. Don't use it any more.
 520                                  * Must implement.
 521                                  */
 522                                 break;
 523                         }
 524
 525                         if (!silly--) {
 526                                 printk(KERN_WARNING "INFTL: infinite loop in "
 527                                         "Virtual Unit Chain 0x%x\n", thisVUC);
 528                                 return BLOCK_NIL;
 529                         }
 530
 531                         /* Skip to next block in chain */
 532                         thisEUN = inftl->PUtable[thisEUN];
 533                 }
 534
 535 hitused:
 536                 if (writeEUN != BLOCK_NIL)
 537                         return writeEUN;
 538
 539
 540                 /*
 541                  * OK. We didn't find one in the existing chain, or there
 542                  * is no existing chain. Allocate a new one.
 543                  */
 544                 writeEUN = INFTL_findfreeblock(inftl, 0);
 545
 546                 if (writeEUN == BLOCK_NIL) {
 547                         /*
 548                          * That didn't work - there were no free blocks just
 549                          * waiting to be picked up. We're going to have to fold
 550                          * a chain to make room.
 551                          */
 552                         thisEUN = INFTL_makefreeblock(inftl, block);
 553
 554                         /*
 555                          * Hopefully we free something, lets try again.
 556                          * This time we are desperate...
 557                          */
 558                         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
 559                                 "to find free EUN to accommodate write to "
 560                                 "VUC %d\n", thisVUC);
 561                         writeEUN = INFTL_findfreeblock(inftl, 1);
 562                         if (writeEUN == BLOCK_NIL) {
 563                                 /*
 564                                  * Ouch. This should never happen - we should
 565                                  * always be able to make some room somehow.
 566                                  * If we get here, we've allocated more storage
 567                                  * space than actual media, or our makefreeblock
 568                                  * routine is missing something.
 569                                  */
 570                                 printk(KERN_WARNING "INFTL: cannot make free "
 571                                         "space.\n");
 572 #ifdef DEBUG
 573                                 INFTL_dumptables(inftl);
 574                                 INFTL_dumpVUchains(inftl);
 575 #endif
 576                                 return BLOCK_NIL;
 577                         }
 578                 }
 579
 580                 /*
 581                  * Insert new block into virtual chain. Firstly update the
 582                  * block headers in flash...
 583                  */
 584                 anac = 0;
 585                 nacs = 0;
 586                 thisEUN = inftl->VUtable[thisVUC];
 587                 if (thisEUN != BLOCK_NIL) {
 588                         inftl_read_oob(mtd, thisEUN * inftl->EraseSize
 589                                        + 8, 8, &retlen, (char *)&oob.u);
 590                         anac = oob.u.a.ANAC + 1;
 591                         nacs = oob.u.a.NACs + 1;
 592                 }
 593
 594                 prev_block = inftl->VUtable[thisVUC];
 595                 if (prev_block < inftl->nb_blocks)
 596                         prev_block -= inftl->firstEUN;
 597
 598                 parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
 599                 parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
 600                 parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
 601                 parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
 602
 603                 oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
 604                 oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
 605                 oob.u.a.ANAC = anac;
 606                 oob.u.a.NACs = nacs;
 607                 oob.u.a.parityPerField = parity;
 608                 oob.u.a.discarded = 0xaa;
 609
 610                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize + 8, 8,
 611                                 &retlen, (char *)&oob.u);
 612
 613                 /* Also back up header... */
 614                 oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
 615                 oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
 616                 oob.u.b.ANAC = anac;
 617                 oob.u.b.NACs = nacs;
 618                 oob.u.b.parityPerField = parity;
 619                 oob.u.b.discarded = 0xaa;
 620
 621                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize +
 622                                 SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
 623
 624                 inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
 625                 inftl->VUtable[thisVUC] = writeEUN;
 626
 627                 inftl->numfreeEUNs--;
 628                 return writeEUN;
 629
 630         } while (silly2--);
 631
 632         printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
 633                 "Unit Chain 0x%x\n", thisVUC);
 634         return BLOCK_NIL;
 635 }
 636
 637 /*
 638  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
 639  */
 640 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
 641 {
 642         struct mtd_info *mtd = inftl->mbd.mtd;
 643         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
 644         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 645         unsigned int thisEUN, status;
 646         int block, silly;
 647         struct inftl_bci bci;
 648         size_t retlen;
 649
 650         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
 651                 "thisVUC=%d)\n", inftl, thisVUC);
 652
 653         memset(BlockUsed, 0, sizeof(BlockUsed));
 654         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 655
 656         thisEUN = inftl->VUtable[thisVUC];
 657         if (thisEUN == BLOCK_NIL) {
 658                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
 659                        "Virtual Unit Chain %d!\n", thisVUC);
 660                 return;
 661         }
 662
 663         /*
 664          * Scan through the Erase Units to determine whether any data is in
 665          * each of the 512-byte blocks within the Chain.
 666          */
 667         silly = MAX_LOOPS;
 668         while (thisEUN < inftl->nb_blocks) {
 669                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
 670                         if (BlockUsed[block] || BlockDeleted[block])
 671                                 continue;
 672
 673                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
 674                                            + (block * SECTORSIZE), 8 , &retlen,
 675                                           (char *)&bci) < 0)
 676                                 status = SECTOR_IGNORE;
 677                         else
 678                                 status = bci.Status | bci.Status1;
 679
 680                         switch(status) {
 681                         case SECTOR_FREE:
 682                         case SECTOR_IGNORE:
 683                                 break;
 684                         case SECTOR_USED:
 685                                 BlockUsed[block] = 1;
 686                                 continue;
 687                         case SECTOR_DELETED:
 688                                 BlockDeleted[block] = 1;
 689                                 continue;
 690                         default:
 691                                 printk(KERN_WARNING "INFTL: unknown status "
 692                                         "for block %d in EUN %d: 0x%x\n",
 693                                         block, thisEUN, status);
 694                         }
 695                 }
 696
 697                 if (!silly--) {
 698                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 699                                 "Unit Chain 0x%x\n", thisVUC);
 700                         return;
 701                 }
 702
 703                 thisEUN = inftl->PUtable[thisEUN];
 704         }
 705
 706         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
 707                 if (BlockUsed[block])
 708                         return;
 709
 710         /*
 711          * For each block in the chain free it and make it available
 712          * for future use. Erase from the oldest unit first.
 713          */
 714         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
 715
 716         for (;;) {
 717                 u16 *prevEUN = &inftl->VUtable[thisVUC];
 718                 thisEUN = *prevEUN;
 719
 720                 /* If the chain is all gone already, we're done */
 721                 if (thisEUN == BLOCK_NIL) {
 722                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
 723                         return;
 724                 }
 725
 726                 /* Find oldest unit in chain. */
 727                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 728                         BUG_ON(thisEUN >= inftl->nb_blocks);
 729
 730                         prevEUN = &inftl->PUtable[thisEUN];
 731                         thisEUN = *prevEUN;
 732                 }
 733
 734                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
 735                       thisEUN, thisVUC);
 736
 737                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 738                         /*
 739                          * Could not erase : mark block as reserved.
 740                          */
 741                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 742                 } else {
 743                         /* Correctly erased : mark it as free */
 744                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 745                         inftl->numfreeEUNs++;
 746                 }
 747
 748                 /* Now sort out whatever was pointing to it... */
 749                 *prevEUN = BLOCK_NIL;
 750
 751                 /* Ideally we'd actually be responsive to new
 752                    requests while we're doing this -- if there's
 753                    free space why should others be made to wait? */
 754                 cond_resched();
 755         }
 756
 757         inftl->VUtable[thisVUC] = BLOCK_NIL;
 758 }
 759
 760 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
 761 {
 762         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 763         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 764         struct mtd_info *mtd = inftl->mbd.mtd;
 765         unsigned int status;
 766         int silly = MAX_LOOPS;
 767         size_t retlen;
 768         struct inftl_bci bci;
 769
 770         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
 771                 "block=%d)\n", inftl, block);
 772
 773         while (thisEUN < inftl->nb_blocks) {
 774                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 775                                    blockofs, 8, &retlen, (char *)&bci) < 0)
 776                         status = SECTOR_IGNORE;
 777                 else
 778                         status = bci.Status | bci.Status1;
 779
 780                 switch (status) {
 781                 case SECTOR_FREE:
 782                 case SECTOR_IGNORE:
 783                         break;
 784                 case SECTOR_DELETED:
 785                         thisEUN = BLOCK_NIL;
 786                         goto foundit;
 787                 case SECTOR_USED:
 788                         goto foundit;
 789                 default:
 790                         printk(KERN_WARNING "INFTL: unknown status for "
 791                                 "block %d in EUN %d: 0x%x\n",
 792                                 block, thisEUN, status);
 793                         break;
 794                 }
 795
 796                 if (!silly--) {
 797                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 798                                 "Unit Chain 0x%x\n",
 799                                 block / (inftl->EraseSize / SECTORSIZE));
 800                         return 1;
 801                 }
 802                 thisEUN = inftl->PUtable[thisEUN];
 803         }
 804
 805 foundit:
 806         if (thisEUN != BLOCK_NIL) {
 807                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 808
 809                 if (inftl_read_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 810                         return -EIO;
 811                 bci.Status = bci.Status1 = SECTOR_DELETED;
 812                 if (inftl_write_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 813                         return -EIO;
 814                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
 815         }
 816         return 0;
 817 }
 818
 819 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 820                             char *buffer)
 821 {
 822         struct INFTLrecord *inftl = (void *)mbd;
 823         unsigned int writeEUN;
 824         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 825         size_t retlen;
 826         struct inftl_oob oob;
 827         char *p, *pend;
 828
 829         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
 830                 "buffer=%p)\n", inftl, block, buffer);
 831
 832         /* Is block all zero? */
 833         pend = buffer + SECTORSIZE;
 834         for (p = buffer; p < pend && !*p; p++)
 835                 ;
 836
 837         if (p < pend) {
 838                 writeEUN = INFTL_findwriteunit(inftl, block);
 839
 840                 if (writeEUN == BLOCK_NIL) {
 841                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
 842                                 "block to write to\n");
 843                         /*
 844                          * If we _still_ haven't got a block to use,
 845                          * we're screwed.
 846                          */
 847                         return 1;
 848                 }
 849
 850                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 851                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 852
 853                 inftl_write(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
 854                             blockofs, SECTORSIZE, &retlen, (char *)buffer,
 855                             (char *)&oob);
 856                 /*
 857                  * need to write SECTOR_USED flags since they are not written
 858                  * in mtd_writeecc
 859                  */
 860         } else {
 861                 INFTL_deleteblock(inftl, block);
 862         }
 863
 864         return 0;
 865 }
 866
 867 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 868                            char *buffer)
 869 {
 870         struct INFTLrecord *inftl = (void *)mbd;
 871         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 872         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 873         struct mtd_info *mtd = inftl->mbd.mtd;
 874         unsigned int status;
 875         int silly = MAX_LOOPS;
 876         struct inftl_bci bci;
 877         size_t retlen;
 878
 879         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
 880                 "buffer=%p)\n", inftl, block, buffer);
 881
 882         while (thisEUN < inftl->nb_blocks) {
 883                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 884                                   blockofs, 8, &retlen, (char *)&bci) < 0)
 885                         status = SECTOR_IGNORE;
 886                 else
 887                         status = bci.Status | bci.Status1;
 888
 889                 switch (status) {
 890                 case SECTOR_DELETED:
 891                         thisEUN = BLOCK_NIL;
 892                         goto foundit;
 893                 case SECTOR_USED:
 894                         goto foundit;
 895                 case SECTOR_FREE:
 896                 case SECTOR_IGNORE:
 897                         break;
 898                 default:
 899                         printk(KERN_WARNING "INFTL: unknown status for "
 900                                 "block %ld in EUN %d: 0x%04x\n",
 901                                 block, thisEUN, status);
 902                         break;
 903                 }
 904
 905                 if (!silly--) {
 906                         printk(KERN_WARNING "INFTL: infinite loop in "
 907                                 "Virtual Unit Chain 0x%lx\n",
 908                                 block / (inftl->EraseSize / SECTORSIZE));
 909                         return 1;
 910                 }
 911
 912                 thisEUN = inftl->PUtable[thisEUN];
 913         }
 914
 915 foundit:
 916         if (thisEUN == BLOCK_NIL) {
 917                 /* The requested block is not on the media, return all 0x00 */
 918                 memset(buffer, 0, SECTORSIZE);
 919         } else {
 920                 size_t retlen;
 921                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 922                 int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);
 923
 924                 /* Handle corrected bit flips gracefully */
 925                 if (ret < 0 && ret != -EUCLEAN)
 926                         return -EIO;
 927         }
 928         return 0;
 929 }
 930
 931 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 932 {
 933         struct INFTLrecord *inftl = (void *)dev;
 934
 935         geo->heads = inftl->heads;
 936         geo->sectors = inftl->sectors;
 937         geo->cylinders = inftl->cylinders;
 938
 939         return 0;
 940 }
 941
 942 static struct mtd_blktrans_ops inftl_tr = {
 943         .name           = "inftl",
 944         .major          = INFTL_MAJOR,
 945         .part_bits      = INFTL_PARTN_BITS,
 946         .blksize        = 512,
 947         .getgeo         = inftl_getgeo,
 948         .readsect       = inftl_readblock,
 949         .writesect      = inftl_writeblock,
 950         .add_mtd        = inftl_add_mtd,
 951         .remove_dev     = inftl_remove_dev,
 952         .owner          = THIS_MODULE,
 953 };
 954
 955 static int __init init_inftl(void)
 956 {
 957         return register_mtd_blktrans(&inftl_tr);
 958 }
 959
 960 static void __exit cleanup_inftl(void)
 961 {
 962         deregister_mtd_blktrans(&inftl_tr);
 963 }
 964
 965 module_init(init_inftl);
 966 module_exit(cleanup_inftl);
 967
 968 MODULE_LICENSE("GPL");
 969 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
 970 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");