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)
  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         kfree(inftl);
 143 }
 144
 145 /*
 146  * Actual INFTL access routines.
 147  */
 148
 149 /*
 150  * Read oob data from flash
 151  */
 152 int inftl_read_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 153                    size_t *retlen, uint8_t *buf)
 154 {
 155         struct mtd_oob_ops ops;
 156         int res;
 157
 158         ops.mode = MTD_OOB_PLACE;
 159         ops.ooboffs = offs & (mtd->writesize - 1);
 160         ops.ooblen = len;
 161         ops.oobbuf = buf;
 162         ops.datbuf = NULL;
 163
 164         res = mtd->read_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 165         *retlen = ops.oobretlen;
 166         return res;
 167 }
 168
 169 /*
 170  * Write oob data to flash
 171  */
 172 int inftl_write_oob(struct mtd_info *mtd, loff_t offs, size_t len,
 173                     size_t *retlen, uint8_t *buf)
 174 {
 175         struct mtd_oob_ops ops;
 176         int res;
 177
 178         ops.mode = MTD_OOB_PLACE;
 179         ops.ooboffs = offs & (mtd->writesize - 1);
 180         ops.ooblen = len;
 181         ops.oobbuf = buf;
 182         ops.datbuf = NULL;
 183
 184         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 185         *retlen = ops.oobretlen;
 186         return res;
 187 }
 188
 189 /*
 190  * Write data and oob to flash
 191  */
 192 static int inftl_write(struct mtd_info *mtd, loff_t offs, size_t len,
 193                        size_t *retlen, uint8_t *buf, uint8_t *oob)
 194 {
 195         struct mtd_oob_ops ops;
 196         int res;
 197
 198         ops.mode = MTD_OOB_PLACE;
 199         ops.ooboffs = offs;
 200         ops.ooblen = mtd->oobsize;
 201         ops.oobbuf = oob;
 202         ops.datbuf = buf;
 203         ops.len = len;
 204
 205         res = mtd->write_oob(mtd, offs & ~(mtd->writesize - 1), &ops);
 206         *retlen = ops.retlen;
 207         return res;
 208 }
 209
 210 /*
 211  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
 212  *      This function is used when the give Virtual Unit Chain.
 213  */
 214 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
 215 {
 216         u16 pot = inftl->LastFreeEUN;
 217         int silly = inftl->nb_blocks;
 218
 219         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
 220                 "desperate=%d)\n", inftl, desperate);
 221
 222         /*
 223          * Normally, we force a fold to happen before we run out of free
 224          * blocks completely.
 225          */
 226         if (!desperate && inftl->numfreeEUNs < 2) {
 227                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
 228                         "EUNs (%d)\n", inftl->numfreeEUNs);
 229                 return 0xffff;
 230         }
 231
 232         /* Scan for a free block */
 233         do {
 234                 if (inftl->PUtable[pot] == BLOCK_FREE) {
 235                         inftl->LastFreeEUN = pot;
 236                         return pot;
 237                 }
 238
 239                 if (++pot > inftl->lastEUN)
 240                         pot = 0;
 241
 242                 if (!silly--) {
 243                         printk(KERN_WARNING "INFTL: no free blocks found!  "
 244                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
 245                         return BLOCK_NIL;
 246                 }
 247         } while (pot != inftl->LastFreeEUN);
 248
 249         return BLOCK_NIL;
 250 }
 251
 252 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
 253 {
 254         u16 BlockMap[MAX_SECTORS_PER_UNIT];
 255         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 256         unsigned int thisEUN, prevEUN, status;
 257         struct mtd_info *mtd = inftl->mbd.mtd;
 258         int block, silly;
 259         unsigned int targetEUN;
 260         struct inftl_oob oob;
 261         size_t retlen;
 262
 263         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
 264                 "pending=%d)\n", inftl, thisVUC, pendingblock);
 265
 266         memset(BlockMap, 0xff, sizeof(BlockMap));
 267         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 268
 269         thisEUN = targetEUN = inftl->VUtable[thisVUC];
 270
 271         if (thisEUN == BLOCK_NIL) {
 272                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
 273                        "Virtual Unit Chain %d!\n", thisVUC);
 274                 return BLOCK_NIL;
 275         }
 276
 277         /*
 278          * Scan to find the Erase Unit which holds the actual data for each
 279          * 512-byte block within the Chain.
 280          */
 281         silly = MAX_LOOPS;
 282         while (thisEUN < inftl->nb_blocks) {
 283                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
 284                         if ((BlockMap[block] != 0xffff) || 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                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 392                         /*
 393                          * Could not erase : mark block as reserved.
 394                          */
 395                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 396                 } else {
 397                         /* Correctly erased : mark it as free */
 398                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 399                         inftl->PUtable[prevEUN] = BLOCK_NIL;
 400                         inftl->numfreeEUNs++;
 401                 }
 402         }
 403
 404         return targetEUN;
 405 }
 406
 407 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
 408 {
 409         /*
 410          * This is the part that needs some cleverness applied.
 411          * For now, I'm doing the minimum applicable to actually
 412          * get the thing to work.
 413          * Wear-levelling and other clever stuff needs to be implemented
 414          * and we also need to do some assessment of the results when
 415          * the system loses power half-way through the routine.
 416          */
 417         u16 LongestChain = 0;
 418         u16 ChainLength = 0, thislen;
 419         u16 chain, EUN;
 420
 421         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
 422                 "pending=%d)\n", inftl, pendingblock);
 423
 424         for (chain = 0; chain < inftl->nb_blocks; chain++) {
 425                 EUN = inftl->VUtable[chain];
 426                 thislen = 0;
 427
 428                 while (EUN <= inftl->lastEUN) {
 429                         thislen++;
 430                         EUN = inftl->PUtable[EUN];
 431                         if (thislen > 0xff00) {
 432                                 printk(KERN_WARNING "INFTL: endless loop in "
 433                                         "Virtual Chain %d: Unit %x\n",
 434                                         chain, EUN);
 435                                 /*
 436                                  * Actually, don't return failure.
 437                                  * Just ignore this chain and get on with it.
 438                                  */
 439                                 thislen = 0;
 440                                 break;
 441                         }
 442                 }
 443
 444                 if (thislen > ChainLength) {
 445                         ChainLength = thislen;
 446                         LongestChain = chain;
 447                 }
 448         }
 449
 450         if (ChainLength < 2) {
 451                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
 452                         "for folding. Failing request\n");
 453                 return BLOCK_NIL;
 454         }
 455
 456         return INFTL_foldchain(inftl, LongestChain, pendingblock);
 457 }
 458
 459 static int nrbits(unsigned int val, int bitcount)
 460 {
 461         int i, total = 0;
 462
 463         for (i = 0; (i < bitcount); i++)
 464                 total += (((0x1 << i) & val) ? 1 : 0);
 465         return total;
 466 }
 467
 468 /*
 469  * INFTL_findwriteunit: Return the unit number into which we can write
 470  *                      for this block. Make it available if it isn't already.
 471  */
 472 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
 473 {
 474         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
 475         unsigned int thisEUN, writeEUN, prev_block, status;
 476         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
 477         struct mtd_info *mtd = inftl->mbd.mtd;
 478         struct inftl_oob oob;
 479         struct inftl_bci bci;
 480         unsigned char anac, nacs, parity;
 481         size_t retlen;
 482         int silly, silly2 = 3;
 483
 484         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
 485                 "block=%d)\n", inftl, block);
 486
 487         do {
 488                 /*
 489                  * Scan the media to find a unit in the VUC which has
 490                  * a free space for the block in question.
 491                  */
 492                 writeEUN = BLOCK_NIL;
 493                 thisEUN = inftl->VUtable[thisVUC];
 494                 silly = MAX_LOOPS;
 495
 496                 while (thisEUN <= inftl->lastEUN) {
 497                         inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 498                                        blockofs, 8, &retlen, (char *)&bci);
 499
 500                         status = bci.Status | bci.Status1;
 501                         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
 502                                 "EUN %d is %x\n", block , writeEUN, status);
 503
 504                         switch(status) {
 505                         case SECTOR_FREE:
 506                                 writeEUN = thisEUN;
 507                                 break;
 508                         case SECTOR_DELETED:
 509                         case SECTOR_USED:
 510                                 /* Can't go any further */
 511                                 goto hitused;
 512                         case SECTOR_IGNORE:
 513                                 break;
 514                         default:
 515                                 /*
 516                                  * Invalid block. Don't use it any more.
 517                                  * Must implement.
 518                                  */
 519                                 break;
 520                         }
 521
 522                         if (!silly--) {
 523                                 printk(KERN_WARNING "INFTL: infinite loop in "
 524                                         "Virtual Unit Chain 0x%x\n", thisVUC);
 525                                 return 0xffff;
 526                         }
 527
 528                         /* Skip to next block in chain */
 529                         thisEUN = inftl->PUtable[thisEUN];
 530                 }
 531
 532 hitused:
 533                 if (writeEUN != BLOCK_NIL)
 534                         return writeEUN;
 535
 536
 537                 /*
 538                  * OK. We didn't find one in the existing chain, or there
 539                  * is no existing chain. Allocate a new one.
 540                  */
 541                 writeEUN = INFTL_findfreeblock(inftl, 0);
 542
 543                 if (writeEUN == BLOCK_NIL) {
 544                         /*
 545                          * That didn't work - there were no free blocks just
 546                          * waiting to be picked up. We're going to have to fold
 547                          * a chain to make room.
 548                          */
 549                         thisEUN = INFTL_makefreeblock(inftl, 0xffff);
 550
 551                         /*
 552                          * Hopefully we free something, lets try again.
 553                          * This time we are desperate...
 554                          */
 555                         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
 556                                 "to find free EUN to accommodate write to "
 557                                 "VUC %d\n", thisVUC);
 558                         writeEUN = INFTL_findfreeblock(inftl, 1);
 559                         if (writeEUN == BLOCK_NIL) {
 560                                 /*
 561                                  * Ouch. This should never happen - we should
 562                                  * always be able to make some room somehow.
 563                                  * If we get here, we've allocated more storage
 564                                  * space than actual media, or our makefreeblock
 565                                  * routine is missing something.
 566                                  */
 567                                 printk(KERN_WARNING "INFTL: cannot make free "
 568                                         "space.\n");
 569 #ifdef DEBUG
 570                                 INFTL_dumptables(inftl);
 571                                 INFTL_dumpVUchains(inftl);
 572 #endif
 573                                 return BLOCK_NIL;
 574                         }
 575                 }
 576
 577                 /*
 578                  * Insert new block into virtual chain. Firstly update the
 579                  * block headers in flash...
 580                  */
 581                 anac = 0;
 582                 nacs = 0;
 583                 thisEUN = inftl->VUtable[thisVUC];
 584                 if (thisEUN != BLOCK_NIL) {
 585                         inftl_read_oob(mtd, thisEUN * inftl->EraseSize
 586                                        + 8, 8, &retlen, (char *)&oob.u);
 587                         anac = oob.u.a.ANAC + 1;
 588                         nacs = oob.u.a.NACs + 1;
 589                 }
 590
 591                 prev_block = inftl->VUtable[thisVUC];
 592                 if (prev_block < inftl->nb_blocks)
 593                         prev_block -= inftl->firstEUN;
 594
 595                 parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
 596                 parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
 597                 parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
 598                 parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
 599
 600                 oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
 601                 oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
 602                 oob.u.a.ANAC = anac;
 603                 oob.u.a.NACs = nacs;
 604                 oob.u.a.parityPerField = parity;
 605                 oob.u.a.discarded = 0xaa;
 606
 607                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize + 8, 8,
 608                                 &retlen, (char *)&oob.u);
 609
 610                 /* Also back up header... */
 611                 oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
 612                 oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
 613                 oob.u.b.ANAC = anac;
 614                 oob.u.b.NACs = nacs;
 615                 oob.u.b.parityPerField = parity;
 616                 oob.u.b.discarded = 0xaa;
 617
 618                 inftl_write_oob(mtd, writeEUN * inftl->EraseSize +
 619                                 SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
 620
 621                 inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
 622                 inftl->VUtable[thisVUC] = writeEUN;
 623
 624                 inftl->numfreeEUNs--;
 625                 return writeEUN;
 626
 627         } while (silly2--);
 628
 629         printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
 630                 "Unit Chain 0x%x\n", thisVUC);
 631         return 0xffff;
 632 }
 633
 634 /*
 635  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
 636  */
 637 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
 638 {
 639         struct mtd_info *mtd = inftl->mbd.mtd;
 640         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
 641         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 642         unsigned int thisEUN, status;
 643         int block, silly;
 644         struct inftl_bci bci;
 645         size_t retlen;
 646
 647         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
 648                 "thisVUC=%d)\n", inftl, thisVUC);
 649
 650         memset(BlockUsed, 0, sizeof(BlockUsed));
 651         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 652
 653         thisEUN = inftl->VUtable[thisVUC];
 654         if (thisEUN == BLOCK_NIL) {
 655                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
 656                        "Virtual Unit Chain %d!\n", thisVUC);
 657                 return;
 658         }
 659
 660         /*
 661          * Scan through the Erase Units to determine whether any data is in
 662          * each of the 512-byte blocks within the Chain.
 663          */
 664         silly = MAX_LOOPS;
 665         while (thisEUN < inftl->nb_blocks) {
 666                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
 667                         if (BlockUsed[block] || BlockDeleted[block])
 668                                 continue;
 669
 670                         if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize)
 671                                            + (block * SECTORSIZE), 8 , &retlen,
 672                                           (char *)&bci) < 0)
 673                                 status = SECTOR_IGNORE;
 674                         else
 675                                 status = bci.Status | bci.Status1;
 676
 677                         switch(status) {
 678                         case SECTOR_FREE:
 679                         case SECTOR_IGNORE:
 680                                 break;
 681                         case SECTOR_USED:
 682                                 BlockUsed[block] = 1;
 683                                 continue;
 684                         case SECTOR_DELETED:
 685                                 BlockDeleted[block] = 1;
 686                                 continue;
 687                         default:
 688                                 printk(KERN_WARNING "INFTL: unknown status "
 689                                         "for block %d in EUN %d: 0x%x\n",
 690                                         block, thisEUN, status);
 691                         }
 692                 }
 693
 694                 if (!silly--) {
 695                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 696                                 "Unit Chain 0x%x\n", thisVUC);
 697                         return;
 698                 }
 699
 700                 thisEUN = inftl->PUtable[thisEUN];
 701         }
 702
 703         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
 704                 if (BlockUsed[block])
 705                         return;
 706
 707         /*
 708          * For each block in the chain free it and make it available
 709          * for future use. Erase from the oldest unit first.
 710          */
 711         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
 712
 713         for (;;) {
 714                 u16 *prevEUN = &inftl->VUtable[thisVUC];
 715                 thisEUN = *prevEUN;
 716
 717                 /* If the chain is all gone already, we're done */
 718                 if (thisEUN == BLOCK_NIL) {
 719                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
 720                         return;
 721                 }
 722
 723                 /* Find oldest unit in chain. */
 724                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 725                         BUG_ON(thisEUN >= inftl->nb_blocks);
 726
 727                         prevEUN = &inftl->PUtable[thisEUN];
 728                         thisEUN = *prevEUN;
 729                 }
 730
 731                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
 732                       thisEUN, thisVUC);
 733
 734                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 735                         /*
 736                          * Could not erase : mark block as reserved.
 737                          */
 738                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 739                 } else {
 740                         /* Correctly erased : mark it as free */
 741                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 742                         inftl->numfreeEUNs++;
 743                 }
 744
 745                 /* Now sort out whatever was pointing to it... */
 746                 *prevEUN = BLOCK_NIL;
 747
 748                 /* Ideally we'd actually be responsive to new
 749                    requests while we're doing this -- if there's
 750                    free space why should others be made to wait? */
 751                 cond_resched();
 752         }
 753
 754         inftl->VUtable[thisVUC] = BLOCK_NIL;
 755 }
 756
 757 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
 758 {
 759         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 760         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 761         struct mtd_info *mtd = inftl->mbd.mtd;
 762         unsigned int status;
 763         int silly = MAX_LOOPS;
 764         size_t retlen;
 765         struct inftl_bci bci;
 766
 767         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
 768                 "block=%d)\n", inftl, block);
 769
 770         while (thisEUN < inftl->nb_blocks) {
 771                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 772                                    blockofs, 8, &retlen, (char *)&bci) < 0)
 773                         status = SECTOR_IGNORE;
 774                 else
 775                         status = bci.Status | bci.Status1;
 776
 777                 switch (status) {
 778                 case SECTOR_FREE:
 779                 case SECTOR_IGNORE:
 780                         break;
 781                 case SECTOR_DELETED:
 782                         thisEUN = BLOCK_NIL;
 783                         goto foundit;
 784                 case SECTOR_USED:
 785                         goto foundit;
 786                 default:
 787                         printk(KERN_WARNING "INFTL: unknown status for "
 788                                 "block %d in EUN %d: 0x%x\n",
 789                                 block, thisEUN, status);
 790                         break;
 791                 }
 792
 793                 if (!silly--) {
 794                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 795                                 "Unit Chain 0x%x\n",
 796                                 block / (inftl->EraseSize / SECTORSIZE));
 797                         return 1;
 798                 }
 799                 thisEUN = inftl->PUtable[thisEUN];
 800         }
 801
 802 foundit:
 803         if (thisEUN != BLOCK_NIL) {
 804                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 805
 806                 if (inftl_read_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 807                         return -EIO;
 808                 bci.Status = bci.Status1 = SECTOR_DELETED;
 809                 if (inftl_write_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 810                         return -EIO;
 811                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
 812         }
 813         return 0;
 814 }
 815
 816 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 817                             char *buffer)
 818 {
 819         struct INFTLrecord *inftl = (void *)mbd;
 820         unsigned int writeEUN;
 821         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 822         size_t retlen;
 823         struct inftl_oob oob;
 824         char *p, *pend;
 825
 826         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
 827                 "buffer=%p)\n", inftl, block, buffer);
 828
 829         /* Is block all zero? */
 830         pend = buffer + SECTORSIZE;
 831         for (p = buffer; p < pend && !*p; p++)
 832                 ;
 833
 834         if (p < pend) {
 835                 writeEUN = INFTL_findwriteunit(inftl, block);
 836
 837                 if (writeEUN == BLOCK_NIL) {
 838                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
 839                                 "block to write to\n");
 840                         /*
 841                          * If we _still_ haven't got a block to use,
 842                          * we're screwed.
 843                          */
 844                         return 1;
 845                 }
 846
 847                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 848                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 849
 850                 inftl_write(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
 851                             blockofs, SECTORSIZE, &retlen, (char *)buffer,
 852                             (char *)&oob);
 853                 /*
 854                  * need to write SECTOR_USED flags since they are not written
 855                  * in mtd_writeecc
 856                  */
 857         } else {
 858                 INFTL_deleteblock(inftl, block);
 859         }
 860
 861         return 0;
 862 }
 863
 864 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 865                            char *buffer)
 866 {
 867         struct INFTLrecord *inftl = (void *)mbd;
 868         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 869         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 870         struct mtd_info *mtd = inftl->mbd.mtd;
 871         unsigned int status;
 872         int silly = MAX_LOOPS;
 873         struct inftl_bci bci;
 874         size_t retlen;
 875
 876         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
 877                 "buffer=%p)\n", inftl, block, buffer);
 878
 879         while (thisEUN < inftl->nb_blocks) {
 880                 if (inftl_read_oob(mtd, (thisEUN * inftl->EraseSize) +
 881                                   blockofs, 8, &retlen, (char *)&bci) < 0)
 882                         status = SECTOR_IGNORE;
 883                 else
 884                         status = bci.Status | bci.Status1;
 885
 886                 switch (status) {
 887                 case SECTOR_DELETED:
 888                         thisEUN = BLOCK_NIL;
 889                         goto foundit;
 890                 case SECTOR_USED:
 891                         goto foundit;
 892                 case SECTOR_FREE:
 893                 case SECTOR_IGNORE:
 894                         break;
 895                 default:
 896                         printk(KERN_WARNING "INFTL: unknown status for "
 897                                 "block %ld in EUN %d: 0x%04x\n",
 898                                 block, thisEUN, status);
 899                         break;
 900                 }
 901
 902                 if (!silly--) {
 903                         printk(KERN_WARNING "INFTL: infinite loop in "
 904                                 "Virtual Unit Chain 0x%lx\n",
 905                                 block / (inftl->EraseSize / SECTORSIZE));
 906                         return 1;
 907                 }
 908
 909                 thisEUN = inftl->PUtable[thisEUN];
 910         }
 911
 912 foundit:
 913         if (thisEUN == BLOCK_NIL) {
 914                 /* The requested block is not on the media, return all 0x00 */
 915                 memset(buffer, 0, SECTORSIZE);
 916         } else {
 917                 size_t retlen;
 918                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 919                 int ret = mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer);
 920
 921                 /* Handle corrected bit flips gracefully */
 922                 if (ret < 0 && ret != -EUCLEAN)
 923                         return -EIO;
 924         }
 925         return 0;
 926 }
 927
 928 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 929 {
 930         struct INFTLrecord *inftl = (void *)dev;
 931
 932         geo->heads = inftl->heads;
 933         geo->sectors = inftl->sectors;
 934         geo->cylinders = inftl->cylinders;
 935
 936         return 0;
 937 }
 938
 939 static struct mtd_blktrans_ops inftl_tr = {
 940         .name           = "inftl",
 941         .major          = INFTL_MAJOR,
 942         .part_bits      = INFTL_PARTN_BITS,
 943         .blksize        = 512,
 944         .getgeo         = inftl_getgeo,
 945         .readsect       = inftl_readblock,
 946         .writesect      = inftl_writeblock,
 947         .add_mtd        = inftl_add_mtd,
 948         .remove_dev     = inftl_remove_dev,
 949         .owner          = THIS_MODULE,
 950 };
 951
 952 static int __init init_inftl(void)
 953 {
 954         return register_mtd_blktrans(&inftl_tr);
 955 }
 956
 957 static void __exit cleanup_inftl(void)
 958 {
 959         deregister_mtd_blktrans(&inftl_tr);
 960 }
 961
 962 module_init(init_inftl);
 963 module_exit(cleanup_inftl);
 964
 965 MODULE_LICENSE("GPL");
 966 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
 967 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");