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   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 <asm/uaccess.h>
  40 #include <asm/errno.h>
  41 #include <asm/io.h>
  42
  43 /*
  44  * Maximum number of loops while examining next block, to have a
  45  * chance to detect consistency problems (they should never happen
  46  * because of the checks done in the mounting.
  47  */
  48 #define MAX_LOOPS 10000
  49
  50 extern void INFTL_dumptables(struct INFTLrecord *inftl);
  51 extern void INFTL_dumpVUchains(struct INFTLrecord *inftl);
  52
  53 static void inftl_add_mtd(struct mtd_blktrans_ops *tr, struct mtd_info *mtd)
  54 {
  55         struct INFTLrecord *inftl;
  56         unsigned long temp;
  57
  58         if (mtd->type != MTD_NANDFLASH)
  59                 return;
  60         /* OK, this is moderately ugly.  But probably safe.  Alternatives? */
  61         if (memcmp(mtd->name, "DiskOnChip", 10))
  62                 return;
  63
  64         if (!mtd->block_isbad) {
  65                 printk(KERN_ERR
  66 "INFTL no longer supports the old DiskOnChip drivers loaded via docprobe.\n"
  67 "Please use the new diskonchip driver under the NAND subsystem.\n");
  68                 return;
  69         }
  70
  71         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: add_mtd for %s\n", mtd->name);
  72
  73         inftl = kmalloc(sizeof(*inftl), GFP_KERNEL);
  74
  75         if (!inftl) {
  76                 printk(KERN_WARNING "INFTL: Out of memory for data structures\n");
  77                 return;
  78         }
  79         memset(inftl, 0, sizeof(*inftl));
  80
  81         inftl->mbd.mtd = mtd;
  82         inftl->mbd.devnum = -1;
  83         inftl->mbd.blksize = 512;
  84         inftl->mbd.tr = tr;
  85         memcpy(&inftl->oobinfo, &mtd->oobinfo, sizeof(struct nand_oobinfo));
  86         inftl->oobinfo.useecc = MTD_NANDECC_PLACEONLY;
  87
  88         if (INFTL_mount(inftl) < 0) {
  89                 printk(KERN_WARNING "INFTL: could not mount device\n");
  90                 kfree(inftl);
  91                 return;
  92         }
  93
  94         /* OK, it's a new one. Set up all the data structures. */
  95
  96         /* Calculate geometry */
  97         inftl->cylinders = 1024;
  98         inftl->heads = 16;
  99
 100         temp = inftl->cylinders * inftl->heads;
 101         inftl->sectors = inftl->mbd.size / temp;
 102         if (inftl->mbd.size % temp) {
 103                 inftl->sectors++;
 104                 temp = inftl->cylinders * inftl->sectors;
 105                 inftl->heads = inftl->mbd.size / temp;
 106
 107                 if (inftl->mbd.size % temp) {
 108                         inftl->heads++;
 109                         temp = inftl->heads * inftl->sectors;
 110                         inftl->cylinders = inftl->mbd.size / temp;
 111                 }
 112         }
 113
 114         if (inftl->mbd.size != inftl->heads * inftl->cylinders * inftl->sectors) {
 115                 /*
 116                   Oh no we don't have
 117                    mbd.size == heads * cylinders * sectors
 118                 */
 119                 printk(KERN_WARNING "INFTL: cannot calculate a geometry to "
 120                        "match size of 0x%lx.\n", inftl->mbd.size);
 121                 printk(KERN_WARNING "INFTL: using C:%d H:%d S:%d "
 122                         "(== 0x%lx sects)\n",
 123                         inftl->cylinders, inftl->heads , inftl->sectors,
 124                         (long)inftl->cylinders * (long)inftl->heads *
 125                         (long)inftl->sectors );
 126         }
 127
 128         if (add_mtd_blktrans_dev(&inftl->mbd)) {
 129                 kfree(inftl->PUtable);
 130                 kfree(inftl->VUtable);
 131                 kfree(inftl);
 132                 return;
 133         }
 134 #ifdef PSYCHO_DEBUG
 135         printk(KERN_INFO "INFTL: Found new nftl%c\n", nftl->mbd.devnum + 'a');
 136 #endif
 137         return;
 138 }
 139
 140 static void inftl_remove_dev(struct mtd_blktrans_dev *dev)
 141 {
 142         struct INFTLrecord *inftl = (void *)dev;
 143
 144         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: remove_dev (i=%d)\n", dev->devnum);
 145
 146         del_mtd_blktrans_dev(dev);
 147
 148         kfree(inftl->PUtable);
 149         kfree(inftl->VUtable);
 150         kfree(inftl);
 151 }
 152
 153 /*
 154  * Actual INFTL access routines.
 155  */
 156
 157 /*
 158  * INFTL_findfreeblock: Find a free Erase Unit on the INFTL partition.
 159  *      This function is used when the give Virtual Unit Chain.
 160  */
 161 static u16 INFTL_findfreeblock(struct INFTLrecord *inftl, int desperate)
 162 {
 163         u16 pot = inftl->LastFreeEUN;
 164         int silly = inftl->nb_blocks;
 165
 166         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_findfreeblock(inftl=%p,"
 167                 "desperate=%d)\n", inftl, desperate);
 168
 169         /*
 170          * Normally, we force a fold to happen before we run out of free
 171          * blocks completely.
 172          */
 173         if (!desperate && inftl->numfreeEUNs < 2) {
 174                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: there are too few free "
 175                         "EUNs (%d)\n", inftl->numfreeEUNs);
 176                 return 0xffff;
 177         }
 178
 179         /* Scan for a free block */
 180         do {
 181                 if (inftl->PUtable[pot] == BLOCK_FREE) {
 182                         inftl->LastFreeEUN = pot;
 183                         return pot;
 184                 }
 185
 186                 if (++pot > inftl->lastEUN)
 187                         pot = 0;
 188
 189                 if (!silly--) {
 190                         printk(KERN_WARNING "INFTL: no free blocks found!  "
 191                                 "EUN range = %d - %d\n", 0, inftl->LastFreeEUN);
 192                         return BLOCK_NIL;
 193                 }
 194         } while (pot != inftl->LastFreeEUN);
 195
 196         return BLOCK_NIL;
 197 }
 198
 199 static u16 INFTL_foldchain(struct INFTLrecord *inftl, unsigned thisVUC, unsigned pendingblock)
 200 {
 201         u16 BlockMap[MAX_SECTORS_PER_UNIT];
 202         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 203         unsigned int thisEUN, prevEUN, status;
 204         int block, silly;
 205         unsigned int targetEUN;
 206         struct inftl_oob oob;
 207         size_t retlen;
 208
 209         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_foldchain(inftl=%p,thisVUC=%d,"
 210                 "pending=%d)\n", inftl, thisVUC, pendingblock);
 211
 212         memset(BlockMap, 0xff, sizeof(BlockMap));
 213         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 214
 215         thisEUN = targetEUN = inftl->VUtable[thisVUC];
 216
 217         if (thisEUN == BLOCK_NIL) {
 218                 printk(KERN_WARNING "INFTL: trying to fold non-existent "
 219                        "Virtual Unit Chain %d!\n", thisVUC);
 220                 return BLOCK_NIL;
 221         }
 222
 223         /*
 224          * Scan to find the Erase Unit which holds the actual data for each
 225          * 512-byte block within the Chain.
 226          */
 227         silly = MAX_LOOPS;
 228         while (thisEUN < inftl->nb_blocks) {
 229                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block ++) {
 230                         if ((BlockMap[block] != 0xffff) || BlockDeleted[block])
 231                                 continue;
 232
 233                         if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize)
 234                              + (block * SECTORSIZE), 16 , &retlen,
 235                              (char *)&oob) < 0)
 236                                 status = SECTOR_IGNORE;
 237                         else
 238                                 status = oob.b.Status | oob.b.Status1;
 239
 240                         switch(status) {
 241                         case SECTOR_FREE:
 242                         case SECTOR_IGNORE:
 243                                 break;
 244                         case SECTOR_USED:
 245                                 BlockMap[block] = thisEUN;
 246                                 continue;
 247                         case SECTOR_DELETED:
 248                                 BlockDeleted[block] = 1;
 249                                 continue;
 250                         default:
 251                                 printk(KERN_WARNING "INFTL: unknown status "
 252                                         "for block %d in EUN %d: %x\n",
 253                                         block, thisEUN, status);
 254                                 break;
 255                         }
 256                 }
 257
 258                 if (!silly--) {
 259                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 260                                 "Unit Chain 0x%x\n", thisVUC);
 261                         return BLOCK_NIL;
 262                 }
 263
 264                 thisEUN = inftl->PUtable[thisEUN];
 265         }
 266
 267         /*
 268          * OK. We now know the location of every block in the Virtual Unit
 269          * Chain, and the Erase Unit into which we are supposed to be copying.
 270          * Go for it.
 271          */
 272         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: folding chain %d into unit %d\n",
 273                 thisVUC, targetEUN);
 274
 275         for (block = 0; block < inftl->EraseSize/SECTORSIZE ; block++) {
 276                 unsigned char movebuf[SECTORSIZE];
 277                 int ret;
 278
 279                 /*
 280                  * If it's in the target EUN already, or if it's pending write,
 281                  * do nothing.
 282                  */
 283                 if (BlockMap[block] == targetEUN || (pendingblock ==
 284                     (thisVUC * (inftl->EraseSize / SECTORSIZE) + block))) {
 285                         continue;
 286                 }
 287
 288                 /*
 289                  * Copy only in non free block (free blocks can only
 290                  * happen in case of media errors or deleted blocks).
 291                  */
 292                 if (BlockMap[block] == BLOCK_NIL)
 293                         continue;
 294
 295                 ret = MTD_READ(inftl->mbd.mtd, (inftl->EraseSize *
 296                         BlockMap[block]) + (block * SECTORSIZE), SECTORSIZE,
 297                         &retlen, movebuf);
 298                 if (ret < 0) {
 299                         ret = MTD_READ(inftl->mbd.mtd, (inftl->EraseSize *
 300                                 BlockMap[block]) + (block * SECTORSIZE),
 301                                 SECTORSIZE, &retlen, movebuf);
 302                         if (ret != -EIO)
 303                                 DEBUG(MTD_DEBUG_LEVEL1, "INFTL: error went "
 304                                         "away on retry?\n");
 305                 }
 306                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 307                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 308                 MTD_WRITEECC(inftl->mbd.mtd, (inftl->EraseSize * targetEUN) +
 309                         (block * SECTORSIZE), SECTORSIZE, &retlen,
 310                         movebuf, (char *)&oob, &inftl->oobinfo);
 311         }
 312
 313         /*
 314          * Newest unit in chain now contains data from _all_ older units.
 315          * So go through and erase each unit in chain, oldest first. (This
 316          * is important, by doing oldest first if we crash/reboot then it
 317          * it is relatively simple to clean up the mess).
 318          */
 319         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: want to erase virtual chain %d\n",
 320                 thisVUC);
 321
 322         for (;;) {
 323                 /* Find oldest unit in chain. */
 324                 thisEUN = inftl->VUtable[thisVUC];
 325                 prevEUN = BLOCK_NIL;
 326                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 327                         prevEUN = thisEUN;
 328                         thisEUN = inftl->PUtable[thisEUN];
 329                 }
 330
 331                 /* Check if we are all done */
 332                 if (thisEUN == targetEUN)
 333                         break;
 334
 335                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 336                         /*
 337                          * Could not erase : mark block as reserved.
 338                          */
 339                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 340                 } else {
 341                         /* Correctly erased : mark it as free */
 342                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 343                         inftl->PUtable[prevEUN] = BLOCK_NIL;
 344                         inftl->numfreeEUNs++;
 345                 }
 346         }
 347
 348         return targetEUN;
 349 }
 350
 351 static u16 INFTL_makefreeblock(struct INFTLrecord *inftl, unsigned pendingblock)
 352 {
 353         /*
 354          * This is the part that needs some cleverness applied.
 355          * For now, I'm doing the minimum applicable to actually
 356          * get the thing to work.
 357          * Wear-levelling and other clever stuff needs to be implemented
 358          * and we also need to do some assessment of the results when
 359          * the system loses power half-way through the routine.
 360          */
 361         u16 LongestChain = 0;
 362         u16 ChainLength = 0, thislen;
 363         u16 chain, EUN;
 364
 365         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_makefreeblock(inftl=%p,"
 366                 "pending=%d)\n", inftl, pendingblock);
 367
 368         for (chain = 0; chain < inftl->nb_blocks; chain++) {
 369                 EUN = inftl->VUtable[chain];
 370                 thislen = 0;
 371
 372                 while (EUN <= inftl->lastEUN) {
 373                         thislen++;
 374                         EUN = inftl->PUtable[EUN];
 375                         if (thislen > 0xff00) {
 376                                 printk(KERN_WARNING "INFTL: endless loop in "
 377                                         "Virtual Chain %d: Unit %x\n",
 378                                         chain, EUN);
 379                                 /*
 380                                  * Actually, don't return failure.
 381                                  * Just ignore this chain and get on with it.
 382                                  */
 383                                 thislen = 0;
 384                                 break;
 385                         }
 386                 }
 387
 388                 if (thislen > ChainLength) {
 389                         ChainLength = thislen;
 390                         LongestChain = chain;
 391                 }
 392         }
 393
 394         if (ChainLength < 2) {
 395                 printk(KERN_WARNING "INFTL: no Virtual Unit Chains available "
 396                         "for folding. Failing request\n");
 397                 return BLOCK_NIL;
 398         }
 399
 400         return INFTL_foldchain(inftl, LongestChain, pendingblock);
 401 }
 402
 403 static int nrbits(unsigned int val, int bitcount)
 404 {
 405         int i, total = 0;
 406
 407         for (i = 0; (i < bitcount); i++)
 408                 total += (((0x1 << i) & val) ? 1 : 0);
 409         return total;
 410 }
 411
 412 /*
 413  * INFTL_findwriteunit: Return the unit number into which we can write
 414  *                      for this block. Make it available if it isn't already.
 415  */
 416 static inline u16 INFTL_findwriteunit(struct INFTLrecord *inftl, unsigned block)
 417 {
 418         unsigned int thisVUC = block / (inftl->EraseSize / SECTORSIZE);
 419         unsigned int thisEUN, writeEUN, prev_block, status;
 420         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize -1);
 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_READOOB(inftl->mbd.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_READOOB(inftl->mbd.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_WRITEOOB(inftl->mbd.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_WRITEOOB(inftl->mbd.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         unsigned char BlockUsed[MAX_SECTORS_PER_UNIT];
 583         unsigned char BlockDeleted[MAX_SECTORS_PER_UNIT];
 584         unsigned int thisEUN, status;
 585         int block, silly;
 586         struct inftl_bci bci;
 587         size_t retlen;
 588
 589         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_trydeletechain(inftl=%p,"
 590                 "thisVUC=%d)\n", inftl, thisVUC);
 591
 592         memset(BlockUsed, 0, sizeof(BlockUsed));
 593         memset(BlockDeleted, 0, sizeof(BlockDeleted));
 594
 595         thisEUN = inftl->VUtable[thisVUC];
 596         if (thisEUN == BLOCK_NIL) {
 597                 printk(KERN_WARNING "INFTL: trying to delete non-existent "
 598                        "Virtual Unit Chain %d!\n", thisVUC);
 599                 return;
 600         }
 601
 602         /*
 603          * Scan through the Erase Units to determine whether any data is in
 604          * each of the 512-byte blocks within the Chain.
 605          */
 606         silly = MAX_LOOPS;
 607         while (thisEUN < inftl->nb_blocks) {
 608                 for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++) {
 609                         if (BlockUsed[block] || BlockDeleted[block])
 610                                 continue;
 611
 612                         if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize)
 613                             + (block * SECTORSIZE), 8 , &retlen,
 614                             (char *)&bci) < 0)
 615                                 status = SECTOR_IGNORE;
 616                         else
 617                                 status = bci.Status | bci.Status1;
 618
 619                         switch(status) {
 620                         case SECTOR_FREE:
 621                         case SECTOR_IGNORE:
 622                                 break;
 623                         case SECTOR_USED:
 624                                 BlockUsed[block] = 1;
 625                                 continue;
 626                         case SECTOR_DELETED:
 627                                 BlockDeleted[block] = 1;
 628                                 continue;
 629                         default:
 630                                 printk(KERN_WARNING "INFTL: unknown status "
 631                                         "for block %d in EUN %d: 0x%x\n",
 632                                         block, thisEUN, status);
 633                         }
 634                 }
 635
 636                 if (!silly--) {
 637                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 638                                 "Unit Chain 0x%x\n", thisVUC);
 639                         return;
 640                 }
 641
 642                 thisEUN = inftl->PUtable[thisEUN];
 643         }
 644
 645         for (block = 0; block < inftl->EraseSize/SECTORSIZE; block++)
 646                 if (BlockUsed[block])
 647                         return;
 648
 649         /*
 650          * For each block in the chain free it and make it available
 651          * for future use. Erase from the oldest unit first.
 652          */
 653         DEBUG(MTD_DEBUG_LEVEL1, "INFTL: deleting empty VUC %d\n", thisVUC);
 654
 655         for (;;) {
 656                 u16 *prevEUN = &inftl->VUtable[thisVUC];
 657                 thisEUN = *prevEUN;
 658
 659                 /* If the chain is all gone already, we're done */
 660                 if (thisEUN == BLOCK_NIL) {
 661                         DEBUG(MTD_DEBUG_LEVEL2, "INFTL: Empty VUC %d for deletion was already absent\n", thisEUN);
 662                         return;
 663                 }
 664
 665                 /* Find oldest unit in chain. */
 666                 while (inftl->PUtable[thisEUN] != BLOCK_NIL) {
 667                         BUG_ON(thisEUN >= inftl->nb_blocks);
 668
 669                         prevEUN = &inftl->PUtable[thisEUN];
 670                         thisEUN = *prevEUN;
 671                 }
 672
 673                 DEBUG(MTD_DEBUG_LEVEL3, "Deleting EUN %d from VUC %d\n",
 674                       thisEUN, thisVUC);
 675
 676                 if (INFTL_formatblock(inftl, thisEUN) < 0) {
 677                         /*
 678                          * Could not erase : mark block as reserved.
 679                          */
 680                         inftl->PUtable[thisEUN] = BLOCK_RESERVED;
 681                 } else {
 682                         /* Correctly erased : mark it as free */
 683                         inftl->PUtable[thisEUN] = BLOCK_FREE;
 684                         inftl->numfreeEUNs++;
 685                 }
 686
 687                 /* Now sort out whatever was pointing to it... */
 688                 *prevEUN = BLOCK_NIL;
 689
 690                 /* Ideally we'd actually be responsive to new
 691                    requests while we're doing this -- if there's
 692                    free space why should others be made to wait? */
 693                 cond_resched();
 694         }
 695
 696         inftl->VUtable[thisVUC] = BLOCK_NIL;
 697 }
 698
 699 static int INFTL_deleteblock(struct INFTLrecord *inftl, unsigned block)
 700 {
 701         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 702         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 703         unsigned int status;
 704         int silly = MAX_LOOPS;
 705         size_t retlen;
 706         struct inftl_bci bci;
 707
 708         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: INFTL_deleteblock(inftl=%p,"
 709                 "block=%d)\n", inftl, block);
 710
 711         while (thisEUN < inftl->nb_blocks) {
 712                 if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize) +
 713                     blockofs, 8, &retlen, (char *)&bci) < 0)
 714                         status = SECTOR_IGNORE;
 715                 else
 716                         status = bci.Status | bci.Status1;
 717
 718                 switch (status) {
 719                 case SECTOR_FREE:
 720                 case SECTOR_IGNORE:
 721                         break;
 722                 case SECTOR_DELETED:
 723                         thisEUN = BLOCK_NIL;
 724                         goto foundit;
 725                 case SECTOR_USED:
 726                         goto foundit;
 727                 default:
 728                         printk(KERN_WARNING "INFTL: unknown status for "
 729                                 "block %d in EUN %d: 0x%x\n",
 730                                 block, thisEUN, status);
 731                         break;
 732                 }
 733
 734                 if (!silly--) {
 735                         printk(KERN_WARNING "INFTL: infinite loop in Virtual "
 736                                 "Unit Chain 0x%x\n",
 737                                 block / (inftl->EraseSize / SECTORSIZE));
 738                         return 1;
 739                 }
 740                 thisEUN = inftl->PUtable[thisEUN];
 741         }
 742
 743 foundit:
 744         if (thisEUN != BLOCK_NIL) {
 745                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 746
 747                 if (MTD_READOOB(inftl->mbd.mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 748                         return -EIO;
 749                 bci.Status = bci.Status1 = SECTOR_DELETED;
 750                 if (MTD_WRITEOOB(inftl->mbd.mtd, ptr, 8, &retlen, (char *)&bci) < 0)
 751                         return -EIO;
 752                 INFTL_trydeletechain(inftl, block / (inftl->EraseSize / SECTORSIZE));
 753         }
 754         return 0;
 755 }
 756
 757 static int inftl_writeblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 758                             char *buffer)
 759 {
 760         struct INFTLrecord *inftl = (void *)mbd;
 761         unsigned int writeEUN;
 762         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 763         size_t retlen;
 764         struct inftl_oob oob;
 765         char *p, *pend;
 766
 767         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_writeblock(inftl=%p,block=%ld,"
 768                 "buffer=%p)\n", inftl, block, buffer);
 769
 770         /* Is block all zero? */
 771         pend = buffer + SECTORSIZE;
 772         for (p = buffer; p < pend && !*p; p++)
 773                 ;
 774
 775         if (p < pend) {
 776                 writeEUN = INFTL_findwriteunit(inftl, block);
 777
 778                 if (writeEUN == BLOCK_NIL) {
 779                         printk(KERN_WARNING "inftl_writeblock(): cannot find "
 780                                 "block to write to\n");
 781                         /*
 782                          * If we _still_ haven't got a block to use,
 783                          * we're screwed.
 784                          */
 785                         return 1;
 786                 }
 787
 788                 memset(&oob, 0xff, sizeof(struct inftl_oob));
 789                 oob.b.Status = oob.b.Status1 = SECTOR_USED;
 790                 MTD_WRITEECC(inftl->mbd.mtd, (writeEUN * inftl->EraseSize) +
 791                         blockofs, SECTORSIZE, &retlen, (char *)buffer,
 792                         (char *)&oob, &inftl->oobinfo);
 793                 /*
 794                  * need to write SECTOR_USED flags since they are not written
 795                  * in mtd_writeecc
 796                  */
 797         } else {
 798                 INFTL_deleteblock(inftl, block);
 799         }
 800
 801         return 0;
 802 }
 803
 804 static int inftl_readblock(struct mtd_blktrans_dev *mbd, unsigned long block,
 805                            char *buffer)
 806 {
 807         struct INFTLrecord *inftl = (void *)mbd;
 808         unsigned int thisEUN = inftl->VUtable[block / (inftl->EraseSize / SECTORSIZE)];
 809         unsigned long blockofs = (block * SECTORSIZE) & (inftl->EraseSize - 1);
 810         unsigned int status;
 811         int silly = MAX_LOOPS;
 812         struct inftl_bci bci;
 813         size_t retlen;
 814
 815         DEBUG(MTD_DEBUG_LEVEL3, "INFTL: inftl_readblock(inftl=%p,block=%ld,"
 816                 "buffer=%p)\n", inftl, block, buffer);
 817
 818         while (thisEUN < inftl->nb_blocks) {
 819                 if (MTD_READOOB(inftl->mbd.mtd, (thisEUN * inftl->EraseSize) +
 820                      blockofs, 8, &retlen, (char *)&bci) < 0)
 821                         status = SECTOR_IGNORE;
 822                 else
 823                         status = bci.Status | bci.Status1;
 824
 825                 switch (status) {
 826                 case SECTOR_DELETED:
 827                         thisEUN = BLOCK_NIL;
 828                         goto foundit;
 829                 case SECTOR_USED:
 830                         goto foundit;
 831                 case SECTOR_FREE:
 832                 case SECTOR_IGNORE:
 833                         break;
 834                 default:
 835                         printk(KERN_WARNING "INFTL: unknown status for "
 836                                 "block %ld in EUN %d: 0x%04x\n",
 837                                 block, thisEUN, status);
 838                         break;
 839                 }
 840
 841                 if (!silly--) {
 842                         printk(KERN_WARNING "INFTL: infinite loop in "
 843                                 "Virtual Unit Chain 0x%lx\n",
 844                                 block / (inftl->EraseSize / SECTORSIZE));
 845                         return 1;
 846                 }
 847
 848                 thisEUN = inftl->PUtable[thisEUN];
 849         }
 850
 851 foundit:
 852         if (thisEUN == BLOCK_NIL) {
 853                 /* The requested block is not on the media, return all 0x00 */
 854                 memset(buffer, 0, SECTORSIZE);
 855         } else {
 856                 size_t retlen;
 857                 loff_t ptr = (thisEUN * inftl->EraseSize) + blockofs;
 858                 if (MTD_READ(inftl->mbd.mtd, ptr, SECTORSIZE, &retlen,
 859                     buffer))
 860                         return -EIO;
 861         }
 862         return 0;
 863 }
 864
 865 static int inftl_getgeo(struct mtd_blktrans_dev *dev, struct hd_geometry *geo)
 866 {
 867         struct INFTLrecord *inftl = (void *)dev;
 868
 869         geo->heads = inftl->heads;
 870         geo->sectors = inftl->sectors;
 871         geo->cylinders = inftl->cylinders;
 872
 873         return 0;
 874 }
 875
 876 static struct mtd_blktrans_ops inftl_tr = {
 877         .name           = "inftl",
 878         .major          = INFTL_MAJOR,
 879         .part_bits      = INFTL_PARTN_BITS,
 880         .getgeo         = inftl_getgeo,
 881         .readsect       = inftl_readblock,
 882         .writesect      = inftl_writeblock,
 883         .add_mtd        = inftl_add_mtd,
 884         .remove_dev     = inftl_remove_dev,
 885         .owner          = THIS_MODULE,
 886 };
 887
 888 extern char inftlmountrev[];
 889
 890 static int __init init_inftl(void)
 891 {
 892         printk(KERN_INFO "INFTL: inftlcore.c $Revision: 1.19 $, "
 893                 "inftlmount.c %s\n", inftlmountrev);
 894
 895         return register_mtd_blktrans(&inftl_tr);
 896 }
 897
 898 static void __exit cleanup_inftl(void)
 899 {
 900         deregister_mtd_blktrans(&inftl_tr);
 901 }
 902
 903 module_init(init_inftl);
 904 module_exit(cleanup_inftl);
 905
 906 MODULE_LICENSE("GPL");
 907 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>, David Woodhouse <dwmw2@infradead.org>, Fabrice Bellard <fabrice.bellard@netgem.com> et al.");
 908 MODULE_DESCRIPTION("Support code for Inverse Flash Translation Layer, used on M-Systems DiskOnChip 2000, Millennium and Millennium Plus");