drivers/mtd/inftlcore.c

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