SAFE public projects git trees. - safe/jmp/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  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
 155  *      This function is used when the give Virtual Unit Chain.
 156  */
 157 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
 158 {
 159         u16 pot = inftl->LastFreeEUN;
 160         int silly = inftl->nb_blocks;
 161
 162         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
 163                 "desperate=%d)\n", inftl, desperate);
 164
 165         /*
 166          * Normally, we force a fold to happen before we run out of free
 167          * blocks completely.
 168          */
 169         if (!desperate && inftl->numfreeEUNs < 2) {
 170                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
 171                         "EUNs (%d)\n", inftl->numfreeEUNs);
 172                 return 0xffff;
 173         }
 174
 175         /* Scan for a free block */
 176         do {
 177                 if (inftl->PUtable[pot] == BLOCK_FREE) {
 178                         inftl->LastFreeEUN = pot;
 179                         return pot;
 180                 }
 181
 182                 if (++pot > inftl->lastEUN)
 183                         pot = 0;
 184
 185                 if (!silly--) {
 186                         printk(KERN_WARNING "INFTL: no free blocks found!  "
 187                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
 188                         return BLOCK_NIL;
 189                 }
 190         } while (pot != inftl->LastFreeEUN);
 191
 192         return BLOCK_NIL;
 193 }
 194
 195 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
 196 {
 197         u16 BlockMap[MAX_SECTORS_PER_UNIT];
 198         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 199         unsigned int thisEUN, prevEUN, status;
 200         struct mtd_info *mtd = inftl->mbd.mtd;
 201         int block, silly;
 202         unsigned int targetEUN;
 203         struct inftl_oob oob;
 204         size_t retlen;
 205
 206         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
 207                 "pending=%d)\n", inftl, thisVUC, pendingblock);
 208
 209         memset(BlockMap, 0xff, sizeof(BlockMap));
 210         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 211
 212         thisEUN = targetEUN = inftl->VUtable[thisVUC];
 213
 214         if (thisEUN == BLOCK_NIL) {
 215                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
 216                        "Virtual Unit Chain %d!\n", thisVUC);
 217                 return BLOCK_NIL;
 218         }
 219
 220         /*
 221          * Scan to find the Erase Unit which holds the actual data for each
 222          * 512-byte block within the Chain.
 223          */
 224         silly = MAX_LOOPS;
 225         while (thisEUN < inftl->nb_blocks) {
 226                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
 227                         if ((BlockMap[block] != 0xffff) || BlockDeleted[block])
 228                                 continue;
 229
 230                         if (mtd->read_oob(mtd, (thisEUN * inftl->EraseSize)
 231                                           + (block * SECTORSIZE), 16 , &retlen,
 232                                           (char *)&oob) < 0)
 233                                 status = SECTOR_IGNORE;
 234                         else
 235                                 status = oob.b.Status | oob.b.Status1;
 236
 237                         switch(status) {
 238                         case SECTOR_FREE:
 239                         case SECTOR_IGNORE:
 240                                 break;
 241                         case SECTOR_USED:
 242                                 BlockMap[block] = thisEUN;
 243                                 continue;
 244                         case SECTOR_DELETED:
 245                                 BlockDeleted[block] = 1;
 246                                 continue;
 247                         default:
 248                                 printk(KERN_WARNING "INFTL: unknown status "
 249                                         "for block %d in EUN %d: %x\n",
 250                                         block, thisEUN, status);
 251                                 break;
 252                         }
 253                 }
 254
 255                 if (!silly--) {
 256                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 257                                 "Unit Chain 0x%x\n", thisVUC);
 258                         return BLOCK_NIL;
 259                 }
 260
 261                 thisEUN = inftl->PUtable[thisEUN];
 262         }
 263
 264         /*
 265          * OK. We now know the location of every block in the Virtual Unit
 266          * Chain, and the Erase Unit into which we are supposed to be copying.
 267          * Go for it.
 268          */
 269         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
 270                 thisVUC, targetEUN);
 271
 272         for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
 273                 unsigned char movebuf[SECTORSIZE];
 274                 int ret;
 275
 276                 /*
 277                  * If it's in the target EUN already, or if it's pending write,
 278                  * do nothing.
 279                  */
 280                 if (BlockMap[block] == targetEUN || (pendingblock ==
 281                     (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
 282                         continue;
 283                 }
 284
 285                 /*
 286                  * Copy only in non free block (free blocks can only
 287                  * happen in case of media errors or deleted blocks).
 288                  */
 289                 if (BlockMap[block] == BLOCK_NIL)
 290                         continue;
 291
 292                 ret = mtd->read(mtd, (inftl->EraseSize * BlockMap[block]) +
 293                                 (block * SECTORSIZE), SECTORSIZE, &retlen,
 294                                 movebuf);
 295                 if (ret < 0) {
 296                         ret = mtd->read(mtd,
 297                                         (inftl->EraseSize * BlockMap[block]) +
 298                                         (block * SECTORSIZE), SECTORSIZE,
 299                                         &retlen, movebuf);
 300                         if (ret != -EIO)
 301                                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
 302                                       "away on retry?\n");
 303                 }
 304                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 305                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 306
 307                 nand_write_raw(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
 308                                (block * SECTORSIZE), SECTORSIZE, &retlen,
 309                                movebuf, (char *)&oob);
 310         }
 311
 312         /*
 313          * Newest unit in chain now contains data from _all_ older units.
 314          * So go through and erase each unit in chain, oldest first. (This
 315          * is important, by doing oldest first if we crash/reboot then it
 316          * it is relatively simple to clean up the mess).
 317          */
 318         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
 319                 thisVUC);
 320
 321         for (;;) {
 322                 /* Find oldest unit in chain. */
 323                 thisEUN = inftl->VUtable[thisVUC];
 324                 prevEUN = BLOCK_NIL;
 325                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 326                         prevEUN = thisEUN;
 327                         thisEUN = inftl->PUtable[thisEUN];
 328                 }
 329
 330                 /* Check if we are all done */
 331                 if (thisEUN == targetEUN)
 332                         break;
 333
 334                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 335                         /*
 336                          * Could not erase : mark block as reserved.
 337                          */
 338                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 339                 } else {
 340                         /* Correctly erased : mark it as free */
 341                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 342                         inftl->PUtable[prevEUN] = BLOCK_NIL;
 343                         inftl->numfreeEUNs++;
 344                 }
 345         }
 346
 347         return targetEUN;
 348 }
 349
 350 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
 351 {
 352         /*
 353          * This is the part that needs some cleverness applied.
 354          * For now, I'm doing the minimum applicable to actually
 355          * get the thing to work.
 356          * Wear-levelling and other clever stuff needs to be implemented
 357          * and we also need to do some assessment of the results when
 358          * the system loses power half-way through the routine.
 359          */
 360         u16 LongestChain = 0;
 361         u16 ChainLength = 0, thislen;
 362         u16 chain, EUN;
 363
 364         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
 365                 "pending=%d)\n", inftl, pendingblock);
 366
 367         for (chain = 0; chain < inftl->nb_blocks; chain++) {
 368                 EUN = inftl->VUtable[chain];
 369                 thislen = 0;
 370
 371                 while (EUN <= inftl->lastEUN) {
 372                         thislen++;
 373                         EUN = inftl->PUtable[EUN];
 374                         if (thislen > 0xff00) {
 375                                 printk(KERN_WARNING "INFTL: endless loop in "
 376                                         "Virtual Chain %d: Unit %x\n",
 377                                         chain, EUN);
 378                                 /*
 379                                  * Actually, don't return failure.
 380                                  * Just ignore this chain and get on with it.
 381                                  */
 382                                 thislen = 0;
 383                                 break;
 384                         }
 385                 }
 386
 387                 if (thislen > ChainLength) {
 388                         ChainLength = thislen;
 389                         LongestChain = chain;
 390                 }
 391         }
 392
 393         if (ChainLength < 2) {
 394                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
 395                         "for folding. Failing request\n");
 396                 return BLOCK_NIL;
 397         }
 398
 399         return INFTL_foldchain(inftl, LongestChain, pendingblock);
 400 }
 401
 402 static int nrbits(unsigned int val, int bitcount)
 403 {
 404         int i, total = 0;
 405
 406         for (i = 0; (i < bitcount); i++)
 407                 total += (((0x1 << i) & val) ? 1 : 0);
 408         return total;
 409 }
 410
 411 /*
 412  * INFTL_findwriteunit: Return the unit number into which we can write
 413  *                      for this block. Make it available if it isn't already.
 414  */
 415 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
 416 {
 417         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
 418         unsigned int thisEUN, writeEUN, prev_block, status;
 419         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
 420         struct mtd_info *mtd = inftl->mbd.mtd;
 421         struct inftl_oob oob;
 422         struct inftl_bci bci;
 423         unsigned char anac, nacs, parity;
 424         size_t retlen;
 425         int silly, silly2 = 3;
 426
 427         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findwriteunit(inftl=%p,"
 428                 "block=%d)\n", inftl, block);
 429
 430         do {
 431                 /*
 432                  * Scan the media to find a unit in the VUC which has
 433                  * a free space for the block in question.
 434                  */
 435                 writeEUN = BLOCK_NIL;
 436                 thisEUN = inftl->VUtable[thisVUC];
 437                 silly = MAX_LOOPS;
 438
 439                 while (thisEUN <= inftl->lastEUN) {
 440                         mtd->read_oob(mtd, (thisEUN * inftl->EraseSize) +
 441                                       blockofs, 8, &retlen, (char *)&bci);
 442
 443                         status = bci.Status | bci.Status1;
 444                         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: status of block %d in "
 445                                 "EUN %d is %x\n", block , writeEUN, status);
 446
 447                         switch(status) {
 448                         case SECTOR_FREE:
 449                                 writeEUN = thisEUN;
 450                                 break;
 451                         case SECTOR_DELETED:
 452                         case SECTOR_USED:
 453                                 /* Can't go any further */
 454                                 goto hitused;
 455                         case SECTOR_IGNORE:
 456                                 break;
 457                         default:
 458                                 /*
 459                                  * Invalid block. Don't use it any more.
 460                                  * Must implement.
 461                                  */
 462                                 break;
 463                         }
 464
 465                         if (!silly--) {
 466                                 printk(KERN_WARNING "INFTL: infinite loop in "
 467                                         "Virtual Unit Chain 0x%x\n", thisVUC);
 468                                 return 0xffff;
 469                         }
 470
 471                         /* Skip to next block in chain */
 472                         thisEUN = inftl->PUtable[thisEUN];
 473                 }
 474
 475 hitused:
 476                 if (writeEUN != BLOCK_NIL)
 477                         return writeEUN;
 478
 479
 480                 /*
 481                  * OK. We didn't find one in the existing chain, or there
 482                  * is no existing chain. Allocate a new one.
 483                  */
 484                 writeEUN = INFTL_findfreeblock(inftl, 0);
 485
 486                 if (writeEUN == BLOCK_NIL) {
 487                         /*
 488                          * That didn't work - there were no free blocks just
 489                          * waiting to be picked up. We're going to have to fold
 490                          * a chain to make room.
 491                          */
 492                         thisEUN = INFTL_makefreeblock(inftl, 0xffff);
 493
 494                         /*
 495                          * Hopefully we free something, lets try again.
 496                          * This time we are desperate...
 497                          */
 498                         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: using desperate==1 "
 499                                 "to find free EUN to accommodate write to "
 500                                 "VUC %d\n", thisVUC);
 501                         writeEUN = INFTL_findfreeblock(inftl, 1);
 502                         if (writeEUN == BLOCK_NIL) {
 503                                 /*
 504                                  * Ouch. This should never happen - we should
 505                                  * always be able to make some room somehow.
 506                                  * If we get here, we've allocated more storage
 507                                  * space than actual media, or our makefreeblock
 508                                  * routine is missing something.
 509                                  */
 510                                 printk(KERN_WARNING "INFTL: cannot make free "
 511                                         "space.\n");
 512 #ifdef DEBUG
 513                                 INFTL_dumptables(inftl);
 514                                 INFTL_dumpVUchains(inftl);
 515 #endif
 516                                 return BLOCK_NIL;
 517                         }
 518                 }
 519
 520                 /*
 521                  * Insert new block into virtual chain. Firstly update the
 522                  * block headers in flash...
 523                  */
 524                 anac = 0;
 525                 nacs = 0;
 526                 thisEUN = inftl->VUtable[thisVUC];
 527                 if (thisEUN != BLOCK_NIL) {
 528                         mtd->read_oob(mtd, thisEUN * inftl->EraseSize
 529                                       + 8, 8, &retlen, (char *)&oob.u);
 530                         anac = oob.u.a.ANAC + 1;
 531                         nacs = oob.u.a.NACs + 1;
 532                 }
 533
 534                 prev_block = inftl->VUtable[thisVUC];
 535                 if (prev_block < inftl->nb_blocks)
 536                         prev_block -= inftl->firstEUN;
 537
 538                 parity = (nrbits(thisVUC, 16) & 0x1) ? 0x1 : 0;
 539                 parity |= (nrbits(prev_block, 16) & 0x1) ? 0x2 : 0;
 540                 parity |= (nrbits(anac, 8) & 0x1) ? 0x4 : 0;
 541                 parity |= (nrbits(nacs, 8) & 0x1) ? 0x8 : 0;
 542
 543                 oob.u.a.virtualUnitNo = cpu_to_le16(thisVUC);
 544                 oob.u.a.prevUnitNo = cpu_to_le16(prev_block);
 545                 oob.u.a.ANAC = anac;
 546                 oob.u.a.NACs = nacs;
 547                 oob.u.a.parityPerField = parity;
 548                 oob.u.a.discarded = 0xaa;
 549
 550                 mtd->write_oob(mtd, writeEUN * inftl->EraseSize + 8, 8,
 551                                &retlen, (char *)&oob.u);
 552
 553                 /* Also back up header... */
 554                 oob.u.b.virtualUnitNo = cpu_to_le16(thisVUC);
 555                 oob.u.b.prevUnitNo = cpu_to_le16(prev_block);
 556                 oob.u.b.ANAC = anac;
 557                 oob.u.b.NACs = nacs;
 558                 oob.u.b.parityPerField = parity;
 559                 oob.u.b.discarded = 0xaa;
 560
 561                 mtd->write_oob(mtd, writeEUN * inftl->EraseSize +
 562                                SECTORSIZE * 4 + 8, 8, &retlen, (char *)&oob.u);
 563
 564                 inftl->PUtable[writeEUN] = inftl->VUtable[thisVUC];
 565                 inftl->VUtable[thisVUC] = writeEUN;
 566
 567                 inftl->numfreeEUNs--;
 568                 return writeEUN;
 569
 570         } while (silly2--);
 571
 572         printk(KERN_WARNING "INFTL: error folding to make room for Virtual "
 573                 "Unit Chain 0x%x\n", thisVUC);
 574         return 0xffff;
 575 }
 576
 577 /*
 578  * Given a Virtual Unit Chain, see if it can be deleted, and if so do it.
 579  */
 580 static void INFTL_trydeletechain(struct INFTLrecord *inftl, unsigned thisVUC)
 581 {
 582         struct mtd_info *mtd = inftl->mbd.mtd;
 583         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
 584         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 585         unsigned int thisEUN, status;
 586         int block, silly;
 587         struct inftl_bci bci;
 588         size_t retlen;
 589
 590         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
 591                 "thisVUC=%d)\n", inftl, thisVUC);
 592
 593         memset(BlockUsed, 0, sizeof(BlockUsed));
 594         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 595
 596         thisEUN = inftl->VUtable[thisVUC];
 597         if (thisEUN == BLOCK_NIL) {
 598                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
 599                        "Virtual Unit Chain %d!\n", thisVUC);
 600                 return;
 601         }
 602
 603         /*
 604          * Scan through the Erase Units to determine whether any data is in
 605          * each of the 512-byte blocks within the Chain.
 606          */
 607         silly = MAX_LOOPS;
 608         while (thisEUN < inftl->nb_blocks) {
 609                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
 610                         if (BlockUsed[block] || BlockDeleted[block])
 611                                 continue;
 612
 613                         if (mtd->read_oob(mtd, (thisEUN * inftl->EraseSize)
 614                                           + (block * SECTORSIZE), 8 , &retlen,
 615                                           (char *)&bci) < 0)
 616                                 status = SECTOR_IGNORE;
 617                         else
 618                                 status = bci.Status | bci.Status1;
 619
 620                         switch(status) {
 621                         case SECTOR_FREE:
 622                         case SECTOR_IGNORE:
 623                                 break;
 624                         case SECTOR_USED:
 625                                 BlockUsed[block] = 1;
 626                                 continue;
 627                         case SECTOR_DELETED:
 628                                 BlockDeleted[block] = 1;
 629                                 continue;
 630                         default:
 631                                 printk(KERN_WARNING "INFTL: unknown status "
 632                                         "for block %d in EUN %d: 0x%x\n",
 633                                         block, thisEUN, status);
 634                         }
 635                 }
 636
 637                 if (!silly--) {
 638                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 639                                 "Unit Chain 0x%x\n", thisVUC);
 640                         return;
 641                 }
 642
 643                 thisEUN = inftl->PUtable[thisEUN];
 644         }
 645
 646         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
 647                 if (BlockUsed[block])
 648                         return;
 649
 650         /*
 651          * For each block in the chain free it and make it available
 652          * for future use. Erase from the oldest unit first.
 653          */
 654         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
 655
 656         for (;;) {
 657                 u16 *prevEUN = &inftl->VUtable[thisVUC];
 658                 thisEUN = *prevEUN;
 659
 660                 /* If the chain is all gone already, we're done */
 661                 if (thisEUN == BLOCK_NIL) {
 662                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
 663                         return;
 664                 }
 665
 666                 /* Find oldest unit in chain. */
 667                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 668                         BUG_ON(thisEUN >= inftl->nb_blocks);
 669
 670                         prevEUN = &inftl->PUtable[thisEUN];
 671                         thisEUN = *prevEUN;
 672                 }
 673
 674                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
 675                       thisEUN, thisVUC);
 676
 677                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 678                         /*
 679                          * Could not erase : mark block as reserved.
 680                          */
 681                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 682                 } else {
 683                         /* Correctly erased : mark it as free */
 684                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 685                         inftl->numfreeEUNs++;
 686                 }
 687
 688                 /* Now sort out whatever was pointing to it... */
 689                 *prevEUN = BLOCK_NIL;
 690
 691                 /* Ideally we'd actually be responsive to new
 692                    requests while we're doing this -- if there's
 693                    free space why should others be made to wait? */
 694                 cond_resched();
 695         }
 696
 697         inftl->VUtable[thisVUC] = BLOCK_NIL;
 698 }
 699
 700 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
 701 {
 702         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 703         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 704         struct mtd_info *mtd = inftl->mbd.mtd;
 705         unsigned int status;
 706         int silly = MAX_LOOPS;
 707         size_t retlen;
 708         struct inftl_bci bci;
 709
 710         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
 711                 "block=%d)\n", inftl, block);
 712
 713         while (thisEUN < inftl->nb_blocks) {
 714                 if (mtd->read_oob(mtd, (thisEUN * inftl->EraseSize) +
 715                                   blockofs, 8, &retlen, (char *)&bci) < 0)
 716                         status = SECTOR_IGNORE;
 717                 else
 718                         status = bci.Status | bci.Status1;
 719
 720                 switch (status) {
 721                 case SECTOR_FREE:
 722                 case SECTOR_IGNORE:
 723                         break;
 724                 case SECTOR_DELETED:
 725                         thisEUN = BLOCK_NIL;
 726                         goto foundit;
 727                 case SECTOR_USED:
 728                         goto foundit;
 729                 default:
 730                         printk(KERN_WARNING "INFTL: unknown status for "
 731                                 "block %d in EUN %d: 0x%x\n",
 732                                 block, thisEUN, status);
 733                         break;
 734                 }
 735
 736                 if (!silly--) {
 737                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 738                                 "Unit Chain 0x%x\n",
 739                                 block / (inftl->EraseSize / SECTORSIZE));
 740                         return 1;
 741                 }
 742                 thisEUN = inftl->PUtable[thisEUN];
 743         }
 744
 745 foundit:
 746         if (thisEUN != BLOCK_NIL) {
 747                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 748
 749                 if (mtd->read_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 750                         return -EIO;
 751                 bci.Status = bci.Status1 = SECTOR_DELETED;
 752                 if (mtd->write_oob(mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 753                         return -EIO;
 754                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
 755         }
 756         return 0;
 757 }
 758
 759 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 760                             char *buffer)
 761 {
 762         struct INFTLrecord *inftl = (void *)mbd;
 763         unsigned int writeEUN;
 764         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 765         size_t retlen;
 766         struct inftl_oob oob;
 767         char *p, *pend;
 768
 769         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
 770                 "buffer=%p)\n", inftl, block, buffer);
 771
 772         /* Is block all zero? */
 773         pend = buffer + SECTORSIZE;
 774         for (p = buffer; p < pend && !*p; p++)
 775                 ;
 776
 777         if (p < pend) {
 778                 writeEUN = INFTL_findwriteunit(inftl, block);
 779
 780                 if (writeEUN == BLOCK_NIL) {
 781                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
 782                                 "block to write to\n");
 783                         /*
 784                          * If we _still_ haven't got a block to use,
 785                          * we're screwed.
 786                          */
 787                         return 1;
 788                 }
 789
 790                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 791                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 792
 793                 nand_write_raw(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
 794                                blockofs, SECTORSIZE, &retlen, (char *)buffer,
 795                                (char *)&oob);
 796                 /*
 797                  * need to write SECTOR_USED flags since they are not written
 798                  * in mtd_writeecc
 799                  */
 800         } else {
 801                 INFTL_deleteblock(inftl, block);
 802         }
 803
 804         return 0;
 805 }
 806
 807 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 808                            char *buffer)
 809 {
 810         struct INFTLrecord *inftl = (void *)mbd;
 811         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 812         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 813         struct mtd_info *mtd = inftl->mbd.mtd;
 814         unsigned int status;
 815         int silly = MAX_LOOPS;
 816         struct inftl_bci bci;
 817         size_t retlen;
 818
 819         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
 820                 "buffer=%p)\n", inftl, block, buffer);
 821
 822         while (thisEUN < inftl->nb_blocks) {
 823                 if (mtd->read_oob(mtd, (thisEUN * inftl->EraseSize) +
 824                                   blockofs, 8, &retlen, (char *)&bci) < 0)
 825                         status = SECTOR_IGNORE;
 826                 else
 827                         status = bci.Status | bci.Status1;
 828
 829                 switch (status) {
 830                 case SECTOR_DELETED:
 831                         thisEUN = BLOCK_NIL;
 832                         goto foundit;
 833                 case SECTOR_USED:
 834                         goto foundit;
 835                 case SECTOR_FREE:
 836                 case SECTOR_IGNORE:
 837                         break;
 838                 default:
 839                         printk(KERN_WARNING "INFTL: unknown status for "
 840                                 "block %ld in EUN %d: 0x%04x\n",
 841                                 block, thisEUN, status);
 842                         break;
 843                 }
 844
 845                 if (!silly--) {
 846                         printk(KERN_WARNING "INFTL: infinite loop in "
 847                                 "Virtual Unit Chain 0x%lx\n",
 848                                 block / (inftl->EraseSize / SECTORSIZE));
 849                         return 1;
 850                 }
 851
 852                 thisEUN = inftl->PUtable[thisEUN];
 853         }
 854
 855 foundit:
 856         if (thisEUN == BLOCK_NIL) {
 857                 /* The requested block is not on the media, return all 0x00 */
 858                 memset(buffer, 0, SECTORSIZE);
 859         } else {
 860                 size_t retlen;
 861                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 862                 if (mtd->read(mtd, ptr, SECTORSIZE, &retlen, buffer))
 863                         return -EIO;
 864         }
 865         return 0;
 866 }
 867
 868 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 869 {
 870         struct INFTLrecord *inftl = (void *)dev;
 871
 872         geo->heads = inftl->heads;
 873         geo->sectors = inftl->sectors;
 874         geo->cylinders = inftl->cylinders;
 875
 876         return 0;
 877 }
 878
 879 static struct mtd_blktrans_ops inftl_tr = {
 880         .name           = "inftl",
 881         .major          = INFTL_MAJOR,
 882         .part_bits      = INFTL_PARTN_BITS,
 883         .getgeo         = inftl_getgeo,
 884         .readsect       = inftl_readblock,
 885         .writesect      = inftl_writeblock,
 886         .add_mtd        = inftl_add_mtd,
 887         .remove_dev     = inftl_remove_dev,
 888         .owner          = THIS_MODULE,
 889 };
 890
 891 static int __init init_inftl(void)
 892 {
 893         printk(KERN_INFO "INFTL: inftlcore.c $Revision: 1.19 $, "
 894                 "inftlmount.c %s\n", inftlmountrev);
 895
 896         return register_mtd_blktrans(&inftl_tr);
 897 }
 898
 899 static void __exit cleanup_inftl(void)
 900 {
 901         deregister_mtd_blktrans(&inftl_tr);
 902 }
 903
 904 module_init(init_inftl);
 905 module_exit(cleanup_inftl);
 906
 907 MODULE_LICENSE("GPL");
 908 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
 909 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");