git.oblomov.eu Git - linux-2.6/blob - 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  * $Id: inftlcore.c,v 1.19 2005/11/07 11:14:20 gleixner Exp $
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2 of the License, or
  15  * (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  */
  26
  27 #include <linux/config.h>
  28 #include <linux/kernel.h>
  29 #include <linux/module.h>
  30 #include <linux/delay.h>
  31 #include <linux/slab.h>
  32 #include <linux/sched.h>
  33 #include <linux/init.h>
  34 #include <linux/kmod.h>
  35 #include <linux/hdreg.h>
  36 #include <linux/mtd/mtd.h>
  37 #include <linux/mtd/nftl.h>
  38 #include <linux/mtd/inftl.h>
  39 #include <linux/mtd/nand.h>
  40 #include <asm/uaccess.h>
  41 #include <asm/errno.h>
  42 #include <asm/io.h>
  43
  44 /*
  45  * Maximum number of loops while examining next block, to have a
  46  * chance to detect consistency problems (they should never happen
  47  * because of the checks done in the mounting.
  48  */
  49 #define MAX_LOOPS 10000
  50
  51 static void inftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  52 {
  53         struct INFTLrecord *inftl;
  54         unsigned long temp;
  55
  56         if (mtd->type != MTD_NANDFLASH)
  57                 return;
  58         /* OK, this is moderately ugly.  But probably safe.  Alternatives? */
  59         if (memcmp(mtd->name, "DiskOnChip", 10))
  60                 return;
  61
  62         if (!mtd->block_isbad) {
  63                 printk(KERN_ERR
  64 "INFTL no longer supports the old DiskOnChip drivers loaded via docprobe.\n"
  65 "Please use the new diskonchip driver under the NAND subsystem.\n");
  66                 return;
  67         }
  68
  69         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: add_mtd for %s\n", mtd->name);
  70
  71         inftl = kmalloc(sizeof(*inftl), GFP_KERNEL);
  72
  73         if (!inftl) {
  74                 printk(KERN_WARNING "INFTL: Out of memory for data structures\n");
  75                 return;
  76         }
  77         memset(inftl, 0, sizeof(*inftl));
  78
  79         inftl->mbd.mtd = mtd;
  80         inftl->mbd.devnum = -1;
  81         inftl->mbd.blksize = 512;
  82         inftl->mbd.tr = tr;
  83
  84         if (INFTL_mount(inftl) < 0) {
  85                 printk(KERN_WARNING "INFTL: could not mount device\n");
  86                 kfree(inftl);
  87                 return;
  88         }
  89
  90         /* OK, it's a new one. Set up all the data structures. */
  91
  92         /* Calculate geometry */
  93         inftl->cylinders = 1024;
  94         inftl->heads = 16;
  95
  96         temp = inftl->cylinders * inftl->heads;
  97         inftl->sectors = inftl->mbd.size / temp;
  98         if (inftl->mbd.size % temp) {
  99                 inftl->sectors++;
 100                 temp = inftl->cylinders * inftl->sectors;
 101                 inftl->heads = inftl->mbd.size / temp;
 102
 103                 if (inftl->mbd.size % temp) {
 104                         inftl->heads++;
 105                         temp = inftl->heads * inftl->sectors;
 106                         inftl->cylinders = inftl->mbd.size / temp;
 107                 }
 108         }
 109
 110         if (inftl->mbd.size != inftl->heads * inftl->cylinders * inftl->sectors) {
 111                 /*
 112                   Oh no we don't have
 113                    mbd.size == heads * cylinders * sectors
 114                 */
 115                 printk(KERN_WARNING "INFTL: cannot calculate a geometry to "
 116                        "match size of 0x%lx.\n", inftl->mbd.size);
 117                 printk(KERN_WARNING "INFTL: using C:%d H:%d S:%d "
 118                         "(== 0x%lx sects)\n",
 119                         inftl->cylinders, inftl->heads , inftl->sectors,
 120                         (long)inftl->cylinders * (long)inftl->heads *
 121                         (long)inftl->sectors );
 122         }
 123
 124         if (add_mtd_blktrans_dev(&inftl->mbd)) {
 125                 kfree(inftl->PUtable);
 126                 kfree(inftl->VUtable);
 127                 kfree(inftl);
 128                 return;
 129         }
 130 #ifdef PSYCHO_DEBUG
 131         printk(KERN_INFO "INFTL: Found new inftl%c\n", inftl->mbd.devnum + 'a');
 132 #endif
 133         return;
 134 }
 135
 136 static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
 137 {
 138         struct INFTLrecord *inftl = (void *)dev;
 139
 140         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: remove_dev (i=%d)\n", dev->devnum);
 141
 142         del_mtd_blktrans_dev(dev);
 143
 144         kfree(inftl->PUtable);
 145         kfree(inftl->VUtable);
 146         kfree(inftl);
 147 }
 148
 149 /*
 150  * Actual INFTL access routines.
 151  */
 152
 153 /*
 154  * Read oob data from flash
 155  */
 156 int inftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 157                    size_t *retlen, uint8_t *buf)
 158 {
 159         struct mtd_oob_ops ops;
 160         int res;
 161
 162         ops.mode = MTD_OOB_PLACE;
 163         ops.ooboffs = offs & (mtd->writesize - 1);
 164         ops.ooblen = len;
 165         ops.oobbuf = buf;
 166         ops.datbuf = NULL;
 167         ops.len = len;
 168
 169         res = mtd->read_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 170         *retlen = ops.retlen;
 171         return res;
 172 }
 173
 174 /*
 175  * Write oob data to flash
 176  */
 177 int inftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 178                     size_t *retlen, uint8_t *buf)
 179 {
 180         struct mtd_oob_ops ops;
 181         int res;
 182
 183         ops.mode = MTD_OOB_PLACE;
 184         ops.ooboffs = offs & (mtd->writesize - 1);
 185         ops.ooblen = len;
 186         ops.oobbuf = buf;
 187         ops.datbuf = NULL;
 188         ops.len = len;
 189
 190         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 191         *retlen = ops.retlen;
 192         return res;
 193 }
 194
 195 /*
 196  * Write data and oob to flash
 197  */
 198 static int inftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
 199                        size_t *retlen, uint8_t *buf, uint8_t *oob)
 200 {
 201         struct mtd_oob_ops ops;
 202         int res;
 203
 204         ops.mode = MTD_OOB_PLACE;
 205         ops.ooboffs = offs;
 206         ops.ooblen = mtd->oobsize;
 207         ops.oobbuf = oob;
 208         ops.datbuf = buf;
 209         ops.len = len;
 210
 211         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 212         *retlen = ops.retlen;
 213         return res;
 214 }
 215
 216 /*
 217  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
 218  *      This function is used when the give Virtual Unit Chain.
 219  */
 220 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
 221 {
 222         u16 pot = inftl->LastFreeEUN;
 223         int silly = inftl->nb_blocks;
 224
 225         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
 226                 "desperate=%d)\n", inftl, desperate);
 227
 228         /*
 229          * Normally, we force a fold to happen before we run out of free
 230          * blocks completely.
 231          */
 232         if (!desperate && inftl->numfreeEUNs < 2) {
 233                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
 234                         "EUNs (%d)\n", inftl->numfreeEUNs);
 235                 return 0xffff;
 236         }
 237
 238         /* Scan for a free block */
 239         do {
 240                 if (inftl->PUtable[pot] == BLOCK_FREE) {
 241                         inftl->LastFreeEUN = pot;
 242                         return pot;
 243                 }
 244
 245                 if (++pot > inftl->lastEUN)
 246                         pot = 0;
 247
 248                 if (!silly--) {
 249                         printk(KERN_WARNING "INFTL: no free blocks found!  "
 250                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
 251                         return BLOCK_NIL;
 252                 }
 253         } while (pot != inftl->LastFreeEUN);
 254
 255         return BLOCK_NIL;
 256 }
 257
 258 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
 259 {
 260         u16 BlockMap[MAX_SECTORS_PER_UNIT];
 261         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 262         unsigned int thisEUN, prevEUN, status;
 263         struct mtd_info *mtd = inftl->mbd.mtd;
 264         int block, silly;
 265         unsigned int targetEUN;
 266         struct inftl_oob oob;
 267         size_t retlen;
 268
 269         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
 270                 "pending=%d)\n", inftl, thisVUC, pendingblock);
 271
 272         memset(BlockMap, 0xff, sizeof(BlockMap));
 273         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 274
 275         thisEUN = targetEUN = inftl->VUtable[thisVUC];
 276
 277         if (thisEUN == BLOCK_NIL) {
 278                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
 279                        "Virtual Unit Chain %d!\n", thisVUC);
 280                 return BLOCK_NIL;
 281         }
 282
 283         /*
 284          * Scan to find the Erase Unit which holds the actual data for each
 285          * 512-byte block within the Chain.
 286          */
 287         silly = MAX_LOOPS;
 288         while (thisEUN < inftl->nb_blocks) {
 289                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
 290                         if ((BlockMap[block] != 0xffff) || BlockDeleted[block])
 291                                 continue;
 292
 293                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
 294                                            + (block * SECTORSIZE), 16, &retlen,
 295                                            (char *)&oob) < 0)
 296                                 status = SECTOR_IGNORE;
 297                         else
 298                                 status = oob.b.Status | oob.b.Status1;
 299
 300                         switch(status) {
 301                         case SECTOR_FREE:
 302                         case SECTOR_IGNORE:
 303                                 break;
 304                         case SECTOR_USED:
 305                                 BlockMap[block] = thisEUN;
 306                                 continue;
 307                         case SECTOR_DELETED:
 308                                 BlockDeleted[block] = 1;
 309                                 continue;
 310                         default:
 311                                 printk(KERN_WARNING "INFTL: unknown status "
 312                                         "for block %d in EUN %d: %x\n",
 313                                         block, thisEUN, status);
 314                                 break;
 315                         }
 316                 }
 317
 318                 if (!silly--) {
 319                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 320                                 "Unit Chain 0x%x\n", thisVUC);
 321                         return BLOCK_NIL;
 322                 }
 323
 324                 thisEUN = inftl->PUtable[thisEUN];
 325         }
 326
 327         /*
 328          * OK. We now know the location of every block in the Virtual Unit
 329          * Chain, and the Erase Unit into which we are supposed to be copying.
 330          * Go for it.
 331          */
 332         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
 333                 thisVUC, targetEUN);
 334
 335         for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
 336                 unsigned char movebuf[SECTORSIZE];
 337                 int ret;
 338
 339                 /*
 340                  * If it's in the target EUN already, or if it's pending write,
 341                  * do nothing.
 342                  */
 343                 if (BlockMap[block] == targetEUN || (pendingblock ==
 344                     (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
 345                         continue;
 346                 }
 347
 348                 /*
 349                  * Copy only in non free block (free blocks can only
 350                  * happen in case of media errors or deleted blocks).
 351                  */
 352                 if (BlockMap[block] == BLOCK_NIL)
 353                         continue;
 354
 355                 ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +
 356                                 (block * SECTORSIZE), SECTORSIZE, &retlen,
 357                                 movebuf);
 358                 if (ret < 0 && ret != -EUCLEAN) {
 359                         ret = mtd->read(mtd,
 360                                         (inftl->EraseSize * BlockMap[block]) +
 361                                         (block * SECTORSIZE), SECTORSIZE,
 362                                         &retlen, movebuf);
 363                         if (ret != -EIO)
 364                                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
 365                                       "away on retry?\n");
 366                 }
 367                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 368                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 369
 370                 inftl_write(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
 371                             (block * SECTORSIZE), SECTORSIZE, &retlen,
 372                             movebuf, (char *)&oob);
 373         }
 374
 375         /*
 376          * Newest unit in chain now contains data from _all_ older units.
 377          * So go through and erase each unit in chain, oldest first. (This
 378          * is important, by doing oldest first if we crash/reboot then it
 379          * it is relatively simple to clean up the mess).
 380          */
 381         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
 382                 thisVUC);
 383
 384         for (;;) {
 385                 /* Find oldest unit in chain. */
 386                 thisEUN = inftl->VUtable[thisVUC];
 387                 prevEUN = BLOCK_NIL;
 388                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 389                         prevEUN = thisEUN;
 390                         thisEUN = inftl->PUtable[thisEUN];
 391                 }
 392
 393                 /* Check if we are all done */
 394                 if (thisEUN == targetEUN)
 395                         break;
 396
 397                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 398                         /*
 399                          * Could not erase : mark block as reserved.
 400                          */
 401                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 402                 } else {
 403                         /* Correctly erased : mark it as free */
 404                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 405                         inftl->PUtable[prevEUN] = BLOCK_NIL;
 406                         inftl->numfreeEUNs++;
 407                 }
 408         }
 409
 410         return targetEUN;
 411 }
 412
 413 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
 414 {
 415         /*
 416          * This is the part that needs some cleverness applied.
 417          * For now, I'm doing the minimum applicable to actually
 418          * get the thing to work.
 419          * Wear-levelling and other clever stuff needs to be implemented
 420          * and we also need to do some assessment of the results when
 421          * the system loses power half-way through the routine.
 422          */
 423         u16 LongestChain = 0;
 424         u16 ChainLength = 0, thislen;
 425         u16 chain, EUN;
 426
 427         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
 428                 "pending=%d)\n", inftl, pendingblock);
 429
 430         for (chain = 0; chain < inftl->nb_blocks; chain++) {
 431                 EUN = inftl->VUtable[chain];
 432                 thislen = 0;
 433
 434                 while (EUN <= inftl->lastEUN) {
 435                         thislen++;
 436                         EUN = inftl->PUtable[EUN];
 437                         if (thislen > 0xff00) {
 438                                 printk(KERN_WARNING "INFTL: endless loop in "
 439                                         "Virtual Chain %d: Unit %x\n",
 440                                         chain, EUN);
 441                                 /*
 442                                  * Actually, don't return failure.
 443                                  * Just ignore this chain and get on with it.
 444                                  */
 445                                 thislen = 0;
 446                                 break;
 447                         }
 448                 }
 449
 450                 if (thislen > ChainLength) {
 451                         ChainLength = thislen;
 452                         LongestChain = chain;
 453                 }
 454         }
 455
 456         if (ChainLength < 2) {
 457                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
 458                         "for folding. Failing request\n");
 459                 return BLOCK_NIL;
 460         }
 461
 462         return INFTL_foldchain(inftl, LongestChain, pendingblock);
 463 }
 464
 465 static int nrbits(unsigned int val, int bitcount)
 466 {
 467         int i, total = 0;
 468
 469         for (i = 0; (i < bitcount); i++)
 470                 total += (((0x1 << i) & val) ? 1 : 0);
 471         return total;
 472 }
 473
 474 /*
 475  * INFTL_findwriteunit: Return the unit number into which we can write
 476  *                      for this block. Make it available if it isn't already.
 477  */
 478 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
 479 {
 480         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
 481         unsigned int thisEUN, writeEUN, prev_block, status;
 482         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
 483         struct mtd_info *mtd = inftl->mbd.mtd;
 484         struct inftl_oob oob;
 485         struct inftl_bci bci;
 486         unsigned char anac, nacs, parity;
 487         size_t retlen;
 488         int silly, silly2 = 3;
 489
 490         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
 491                 "block=%d)\n", inftl, block);
 492
 493         do {
 494                 /*
 495                  * Scan the media to find a unit in the VUC which has
 496                  * a free space for the block in question.
 497                  */
 498                 writeEUN = BLOCK_NIL;
 499                 thisEUN = inftl->VUtable[thisVUC];
 500                 silly = MAX_LOOPS;
 501
 502                 while (thisEUN <= inftl->lastEUN) {
 503                         inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 504                                        blockofs, 8, &retlen, (char *)&bci);
 505
 506                         status = bci.Status | bci.Status1;
 507                         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
 508                                 "EUN %d is %x\n", block , writeEUN, status);
 509
 510                         switch(status) {
 511                         case SECTOR_FREE:
 512                                 writeEUN = thisEUN;
 513                                 break;
 514                         case SECTOR_DELETED:
 515                         case SECTOR_USED:
 516                                 /* Can't go any further */
 517                                 goto hitused;
 518                         case SECTOR_IGNORE:
 519                                 break;
 520                         default:
 521                                 /*
 522                                  * Invalid block. Don't use it any more.
 523                                  * Must implement.
 524                                  */
 525                                 break;
 526                         }
 527
 528                         if (!silly--) {
 529                                 printk(KERN_WARNING "INFTL: infinite loop in "
 530                                         "Virtual Unit Chain 0x%x\n", thisVUC);
 531                                 return 0xffff;
 532                         }
 533
 534                         /* Skip to next block in chain */
 535                         thisEUN = inftl->PUtable[thisEUN];
 536                 }
 537
 538 hitused:
 539                 if (writeEUN != BLOCK_NIL)
 540                         return writeEUN;
 541
 542
 543                 /*
 544                  * OK. We didn't find one in the existing chain, or there
 545                  * is no existing chain. Allocate a new one.
 546                  */
 547                 writeEUN = INFTL_findfreeblock(inftl, 0);
 548
 549                 if (writeEUN == BLOCK_NIL) {
 550                         /*
 551                          * That didn't work - there were no free blocks just
 552                          * waiting to be picked up. We're going to have to fold
 553                          * a chain to make room.
 554                          */
 555                         thisEUN = INFTL_makefreeblock(inftl, 0xffff);
 556
 557                         /*
 558                          * Hopefully we free something, lets try again.
 559                          * This time we are desperate...
 560                          */
 561                         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
 562                                 "to find free EUN to accommodate write to "
 563                                 "VUC %d\n", thisVUC);
 564                         writeEUN = INFTL_findfreeblock(inftl, 1);
 565                         if (writeEUN == BLOCK_NIL) {
 566                                 /*
 567                                  * Ouch. This should never happen - we should
 568                                  * always be able to make some room somehow.
 569                                  * If we get here, we've allocated more storage
 570                                  * space than actual media, or our makefreeblock
 571                                  * routine is missing something.
 572                                  */
 573                                 printk(KERN_WARNING "INFTL: cannot make free "
 574                                         "space.\n");
 575 #ifdef DEBUG
 576                                 INFTL_dumptables(inftl);
 577                                 INFTL_dumpVUchains(inftl);
 578 #endif
 579                                 return BLOCK_NIL;
 580                         }
 581                 }
 582
 583                 /*
 584                  * Insert new block into virtual chain. Firstly update the
 585                  * block headers in flash...
 586                  */
 587                 anac = 0;
 588                 nacs = 0;
 589                 thisEUN = inftl->VUtable[thisVUC];
 590                 if (thisEUN != BLOCK_NIL) {
 591                         inftl_read_oob(mtd, thisEUN * inftl->EraseSize
 592                                        + 8, 8, &retlen, (char *)&oob.u);
 593                         anac = oob.u.a.ANAC + 1;
 594                         nacs = oob.u.a.NACs + 1;
 595                 }
 596
 597                 prev_block = inftl->VUtable[thisVUC];
 598                 if (prev_block < inftl->nb_blocks)
 599                         prev_block -= inftl->firstEUN;
 600
 601                 parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
 602                 parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
 603                 parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
 604                 parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
 605
 606                 oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
 607                 oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
 608                 oob.u.a.ANAC = anac;
 609                 oob.u.a.NACs = nacs;
 610                 oob.u.a.parityPerField = parity;
 611                 oob.u.a.discarded = 0xaa;
 612
 613                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize + 8, 8,
 614                                 &retlen, (char *)&oob.u);
 615
 616                 /* Also back up header... */
 617                 oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
 618                 oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
 619                 oob.u.b.ANAC = anac;
 620                 oob.u.b.NACs = nacs;
 621                 oob.u.b.parityPerField = parity;
 622                 oob.u.b.discarded = 0xaa;
 623
 624                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize +
 625                                 SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
 626
 627                 inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
 628                 inftl->VUtable[thisVUC] = writeEUN;
 629
 630                 inftl->numfreeEUNs--;
 631                 return writeEUN;
 632
 633         } while (silly2--);
 634
 635         printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
 636                 "Unit Chain 0x%x\n", thisVUC);
 637         return 0xffff;
 638 }
 639
 640 /*
 641  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
 642  */
 643 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
 644 {
 645         struct mtd_info *mtd = inftl->mbd.mtd;
 646         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
 647         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 648         unsigned int thisEUN, status;
 649         int block, silly;
 650         struct inftl_bci bci;
 651         size_t retlen;
 652
 653         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
 654                 "thisVUC=%d)\n", inftl, thisVUC);
 655
 656         memset(BlockUsed, 0, sizeof(BlockUsed));
 657         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 658
 659         thisEUN = inftl->VUtable[thisVUC];
 660         if (thisEUN == BLOCK_NIL) {
 661                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
 662                        "Virtual Unit Chain %d!\n", thisVUC);
 663                 return;
 664         }
 665
 666         /*
 667          * Scan through the Erase Units to determine whether any data is in
 668          * each of the 512-byte blocks within the Chain.
 669          */
 670         silly = MAX_LOOPS;
 671         while (thisEUN < inftl->nb_blocks) {
 672                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
 673                         if (BlockUsed[block] || BlockDeleted[block])
 674                                 continue;
 675
 676                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
 677                                            + (block * SECTORSIZE), 8 , &retlen,
 678                                           (char *)&bci) < 0)
 679                                 status = SECTOR_IGNORE;
 680                         else
 681                                 status = bci.Status | bci.Status1;
 682
 683                         switch(status) {
 684                         case SECTOR_FREE:
 685                         case SECTOR_IGNORE:
 686                                 break;
 687                         case SECTOR_USED:
 688                                 BlockUsed[block] = 1;
 689                                 continue;
 690                         case SECTOR_DELETED:
 691                                 BlockDeleted[block] = 1;
 692                                 continue;
 693                         default:
 694                                 printk(KERN_WARNING "INFTL: unknown status "
 695                                         "for block %d in EUN %d: 0x%x\n",
 696                                         block, thisEUN, status);
 697                         }
 698                 }
 699
 700                 if (!silly--) {
 701                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 702                                 "Unit Chain 0x%x\n", thisVUC);
 703                         return;
 704                 }
 705
 706                 thisEUN = inftl->PUtable[thisEUN];
 707         }
 708
 709         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
 710                 if (BlockUsed[block])
 711                         return;
 712
 713         /*
 714          * For each block in the chain free it and make it available
 715          * for future use. Erase from the oldest unit first.
 716          */
 717         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
 718
 719         for (;;) {
 720                 u16 *prevEUN = &inftl->VUtable[thisVUC];
 721                 thisEUN = *prevEUN;
 722
 723                 /* If the chain is all gone already, we're done */
 724                 if (thisEUN == BLOCK_NIL) {
 725                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
 726                         return;
 727                 }
 728
 729                 /* Find oldest unit in chain. */
 730                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 731                         BUG_ON(thisEUN >= inftl->nb_blocks);
 732
 733                         prevEUN = &inftl->PUtable[thisEUN];
 734                         thisEUN = *prevEUN;
 735                 }
 736
 737                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
 738                       thisEUN, thisVUC);
 739
 740                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 741                         /*
 742                          * Could not erase : mark block as reserved.
 743                          */
 744                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 745                 } else {
 746                         /* Correctly erased : mark it as free */
 747                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 748                         inftl->numfreeEUNs++;
 749                 }
 750
 751                 /* Now sort out whatever was pointing to it... */
 752                 *prevEUN = BLOCK_NIL;
 753
 754                 /* Ideally we'd actually be responsive to new
 755                    requests while we're doing this -- if there's
 756                    free space why should others be made to wait? */
 757                 cond_resched();
 758         }
 759
 760         inftl->VUtable[thisVUC] = BLOCK_NIL;
 761 }
 762
 763 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
 764 {
 765         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 766         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 767         struct mtd_info *mtd = inftl->mbd.mtd;
 768         unsigned int status;
 769         int silly = MAX_LOOPS;
 770         size_t retlen;
 771         struct inftl_bci bci;
 772
 773         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
 774                 "block=%d)\n", inftl, block);
 775
 776         while (thisEUN < inftl->nb_blocks) {
 777                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 778                                    blockofs, 8, &retlen, (char *)&bci) < 0)
 779                         status = SECTOR_IGNORE;
 780                 else
 781                         status = bci.Status | bci.Status1;
 782
 783                 switch (status) {
 784                 case SECTOR_FREE:
 785                 case SECTOR_IGNORE:
 786                         break;
 787                 case SECTOR_DELETED:
 788                         thisEUN = BLOCK_NIL;
 789                         goto foundit;
 790                 case SECTOR_USED:
 791                         goto foundit;
 792                 default:
 793                         printk(KERN_WARNING "INFTL: unknown status for "
 794                                 "block %d in EUN %d: 0x%x\n",
 795                                 block, thisEUN, status);
 796                         break;
 797                 }
 798
 799                 if (!silly--) {
 800                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 801                                 "Unit Chain 0x%x\n",
 802                                 block / (inftl->EraseSize / SECTORSIZE));
 803                         return 1;
 804                 }
 805                 thisEUN = inftl->PUtable[thisEUN];
 806         }
 807
 808 foundit:
 809         if (thisEUN != BLOCK_NIL) {
 810                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 811
 812                 if (inftl_read_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 813                         return -EIO;
 814                 bci.Status = bci.Status1 = SECTOR_DELETED;
 815                 if (inftl_write_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 816                         return -EIO;
 817                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
 818         }
 819         return 0;
 820 }
 821
 822 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 823                             char *buffer)
 824 {
 825         struct INFTLrecord *inftl = (void *)mbd;
 826         unsigned int writeEUN;
 827         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 828         size_t retlen;
 829         struct inftl_oob oob;
 830         char *p, *pend;
 831
 832         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
 833                 "buffer=%p)\n", inftl, block, buffer);
 834
 835         /* Is block all zero? */
 836         pend = buffer + SECTORSIZE;
 837         for (p = buffer; p < pend && !*p; p++)
 838                 ;
 839
 840         if (p < pend) {
 841                 writeEUN = INFTL_findwriteunit(inftl, block);
 842
 843                 if (writeEUN == BLOCK_NIL) {
 844                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
 845                                 "block to write to\n");
 846                         /*
 847                          * If we _still_ haven't got a block to use,
 848                          * we're screwed.
 849                          */
 850                         return 1;
 851                 }
 852
 853                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 854                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 855
 856                 inftl_write(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
 857                             blockofs, SECTORSIZE, &retlen, (char *)buffer,
 858                             (char *)&oob);
 859                 /*
 860                  * need to write SECTOR_USED flags since they are not written
 861                  * in mtd_writeecc
 862                  */
 863         } else {
 864                 INFTL_deleteblock(inftl, block);
 865         }
 866
 867         return 0;
 868 }
 869
 870 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 871                            char *buffer)
 872 {
 873         struct INFTLrecord *inftl = (void *)mbd;
 874         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 875         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 876         struct mtd_info *mtd = inftl->mbd.mtd;
 877         unsigned int status;
 878         int silly = MAX_LOOPS;
 879         struct inftl_bci bci;
 880         size_t retlen;
 881
 882         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
 883                 "buffer=%p)\n", inftl, block, buffer);
 884
 885         while (thisEUN < inftl->nb_blocks) {
 886                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 887                                   blockofs, 8, &retlen, (char *)&bci) < 0)
 888                         status = SECTOR_IGNORE;
 889                 else
 890                         status = bci.Status | bci.Status1;
 891
 892                 switch (status) {
 893                 case SECTOR_DELETED:
 894                         thisEUN = BLOCK_NIL;
 895                         goto foundit;
 896                 case SECTOR_USED:
 897                         goto foundit;
 898                 case SECTOR_FREE:
 899                 case SECTOR_IGNORE:
 900                         break;
 901                 default:
 902                         printk(KERN_WARNING "INFTL: unknown status for "
 903                                 "block %ld in EUN %d: 0x%04x\n",
 904                                 block, thisEUN, status);
 905                         break;
 906                 }
 907
 908                 if (!silly--) {
 909                         printk(KERN_WARNING "INFTL: infinite loop in "
 910                                 "Virtual Unit Chain 0x%lx\n",
 911                                 block / (inftl->EraseSize / SECTORSIZE));
 912                         return 1;
 913                 }
 914
 915                 thisEUN = inftl->PUtable[thisEUN];
 916         }
 917
 918 foundit:
 919         if (thisEUN == BLOCK_NIL) {
 920                 /* The requested block is not on the media, return all 0x00 */
 921                 memset(buffer, 0, SECTORSIZE);
 922         } else {
 923                 size_t retlen;
 924                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 925                 int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);
 926
 927                 /* Handle corrected bit flips gracefully */
 928                 if (ret < 0 && ret != -EUCLEAN)
 929                         return -EIO;
 930         }
 931         return 0;
 932 }
 933
 934 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 935 {
 936         struct INFTLrecord *inftl = (void *)dev;
 937
 938         geo->heads = inftl->heads;
 939         geo->sectors = inftl->sectors;
 940         geo->cylinders = inftl->cylinders;
 941
 942         return 0;
 943 }
 944
 945 static struct mtd_blktrans_ops inftl_tr = {
 946         .name           = "inftl",
 947         .major          = INFTL_MAJOR,
 948         .part_bits      = INFTL_PARTN_BITS,
 949         .getgeo         = inftl_getgeo,
 950         .readsect       = inftl_readblock,
 951         .writesect      = inftl_writeblock,
 952         .add_mtd        = inftl_add_mtd,
 953         .remove_dev     = inftl_remove_dev,
 954         .owner          = THIS_MODULE,
 955 };
 956
 957 static int __init init_inftl(void)
 958 {
 959         printk(KERN_INFO "INFTL: inftlcore.c $Revision: 1.19 $, "
 960                 "inftlmount.c %s\n", inftlmountrev);
 961
 962         return register_mtd_blktrans(&inftl_tr);
 963 }
 964
 965 static void __exit cleanup_inftl(void)
 966 {
 967         deregister_mtd_blktrans(&inftl_tr);
 968 }
 969
 970 module_init(init_inftl);
 971 module_exit(cleanup_inftl);
 972
 973 MODULE_LICENSE("GPL");
 974 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
 975 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");