yaffs_tagscompat.c

   1 /*
   2  * YAFFS: Yet another FFS. A NAND-flash specific file system.
   3  * yaffs_tagscompat.h: Tags compatability layer to use YAFFS1 formatted NAND.
   4  *
   5  * Copyright (C) 2002 Aleph One Ltd.
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  *
  13  * $Id: yaffs_tagscompat.c,v 1.1 2004-11-03 08:14:07 charles Exp $
  14  */
  15
  16 #include "yaffs_guts.h"
  17 #include "yaffs_tagscompat.h"
  18 #include "yaffs_ecc.h"
  19
  20 static void yaffs_HandleReadDataError(yaffs_Device *dev,int chunkInNAND);
  21 static void yaffs_CheckWrittenBlock(yaffs_Device *dev,int chunkInNAND);
  22 static void yaffs_HandleWriteChunkOk(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare);
  23 static void yaffs_HandleUpdateChunk(yaffs_Device *dev,int chunkInNAND, const yaffs_Spare *spare);
  24 static void yaffs_HandleWriteChunkError(yaffs_Device *dev,int chunkInNAND);
  25
  26
  27
  28 static const char yaffs_countBitsTable[256] =
  29 {
  30 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,
  31 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  32 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  33 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  34 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  35 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  36 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  37 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  38 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  39 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  40 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  41 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  42 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  43 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  44 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  45 4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8
  46 };
  47
  48 static int yaffs_CountBits(__u8 x)
  49 {
  50         int retVal;
  51         retVal = yaffs_countBitsTable[x];
  52         return retVal;
  53 }
  54
  55
  56 /////////////// Tags ECC calculations ///////////////////
  57
  58 void yaffs_CalcECC(const __u8 *data, yaffs_Spare *spare)
  59 {
  60         yaffs_ECCCalculate(data , spare->ecc1);
  61         yaffs_ECCCalculate(&data[256] , spare->ecc2);
  62 }
  63
  64 void yaffs_CalcTagsECC(yaffs_Tags *tags)
  65 {
  66         // Calculate an ecc
  67
  68         unsigned char *b = ((yaffs_TagsUnion *)tags)->asBytes;
  69         unsigned  i,j;
  70         unsigned  ecc = 0;
  71         unsigned bit = 0;
  72
  73         tags->ecc = 0;
  74
  75         for(i = 0; i < 8; i++)
  76         {
  77                 for(j = 1; j &0xff; j<<=1)
  78                 {
  79                         bit++;
  80                         if(b[i] & j)
  81                         {
  82                                 ecc ^= bit;
  83                         }
  84                 }
  85         }
  86
  87         tags->ecc = ecc;
  88
  89
  90 }
  91
  92 int  yaffs_CheckECCOnTags(yaffs_Tags *tags)
  93 {
  94         unsigned ecc = tags->ecc;
  95
  96         yaffs_CalcTagsECC(tags);
  97
  98         ecc ^= tags->ecc;
  99
 100         if(ecc && ecc <= 64)
 101         {
 102                 // TODO: Handle the failure better. Retire?
 103                 unsigned char *b = ((yaffs_TagsUnion *)tags)->asBytes;
 104
 105                 ecc--;
 106
 107                 b[ecc / 8] ^= (1 << (ecc & 7));
 108
 109                 // Now recvalc the ecc
 110                 yaffs_CalcTagsECC(tags);
 111
 112                 return 1; // recovered error
 113         }
 114         else if(ecc)
 115         {
 116                 // Wierd ecc failure value
 117                 // TODO Need to do somethiong here
 118                 return -1; //unrecovered error
 119         }
 120
 121         return 0;
 122 }
 123
 124 //////////////////////////// Tags ///////////////////////////////////////
 125
 126 static void yaffs_LoadTagsIntoSpare(yaffs_Spare *sparePtr, yaffs_Tags *tagsPtr)
 127 {
 128         yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
 129
 130         yaffs_CalcTagsECC(tagsPtr);
 131
 132         sparePtr->tagByte0 = tu->asBytes[0];
 133         sparePtr->tagByte1 = tu->asBytes[1];
 134         sparePtr->tagByte2 = tu->asBytes[2];
 135         sparePtr->tagByte3 = tu->asBytes[3];
 136         sparePtr->tagByte4 = tu->asBytes[4];
 137         sparePtr->tagByte5 = tu->asBytes[5];
 138         sparePtr->tagByte6 = tu->asBytes[6];
 139         sparePtr->tagByte7 = tu->asBytes[7];
 140 }
 141
 142 static void yaffs_GetTagsFromSpare(yaffs_Device *dev, yaffs_Spare *sparePtr,yaffs_Tags *tagsPtr)
 143 {
 144         yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
 145         int result;
 146
 147         tu->asBytes[0]= sparePtr->tagByte0;
 148         tu->asBytes[1]= sparePtr->tagByte1;
 149         tu->asBytes[2]= sparePtr->tagByte2;
 150         tu->asBytes[3]= sparePtr->tagByte3;
 151         tu->asBytes[4]= sparePtr->tagByte4;
 152         tu->asBytes[5]= sparePtr->tagByte5;
 153         tu->asBytes[6]= sparePtr->tagByte6;
 154         tu->asBytes[7]= sparePtr->tagByte7;
 155
 156         result =  yaffs_CheckECCOnTags(tagsPtr);
 157         if(result> 0)
 158         {
 159                 dev->tagsEccFixed++;
 160         }
 161         else if(result <0)
 162         {
 163                 dev->tagsEccUnfixed++;
 164         }
 165 }
 166
 167 static void yaffs_SpareInitialise(yaffs_Spare *spare)
 168 {
 169         memset(spare,0xFF,sizeof(yaffs_Spare));
 170 }
 171
 172
 173
 174
 175 static int yaffs_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, const __u8 *data, yaffs_Spare *spare)
 176 {
 177         if(chunkInNAND < dev->startBlock * dev->nChunksPerBlock)
 178         {
 179                 T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs chunk %d is not valid" TENDSTR),chunkInNAND));
 180                 return YAFFS_FAIL;
 181         }
 182
 183         dev->nPageWrites++;
 184         return dev->writeChunkToNAND(dev,chunkInNAND,data,spare);
 185 }
 186
 187
 188
 189 static int yaffs_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,
 190                                                         int chunkInNAND,
 191                                                         __u8 *data,
 192                                                         yaffs_Spare *spare,
 193                                                         yaffs_ECCResult *eccResult,
 194                                                         int doErrorCorrection)
 195 {
 196         int retVal;
 197         yaffs_Spare localSpare;
 198
 199         dev->nPageReads++;
 200
 201
 202
 203
 204         if(!spare && data)
 205         {
 206                 // If we don't have a real spare, then we use a local one.
 207                 // Need this for the calculation of the ecc
 208                 spare = &localSpare;
 209         }
 210
 211
 212         if(!dev->useNANDECC)
 213         {
 214                 retVal  = dev->readChunkFromNAND(dev,chunkInNAND,data,spare);
 215                 if(data && doErrorCorrection)
 216                 {
 217                         // Do ECC correction
 218                         //Todo handle any errors
 219                 int eccResult1,eccResult2;
 220                 __u8 calcEcc[3];
 221
 222                         yaffs_ECCCalculate(data,calcEcc);
 223                         eccResult1 = yaffs_ECCCorrect (data,spare->ecc1, calcEcc);
 224                         yaffs_ECCCalculate(&data[256],calcEcc);
 225                         eccResult2 = yaffs_ECCCorrect(&data[256],spare->ecc2, calcEcc);
 226
 227                         if(eccResult1>0)
 228                         {
 229                                 T(YAFFS_TRACE_ERROR, (TSTR("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
 230                                 dev->eccFixed++;
 231                         }
 232                         else if(eccResult1<0)
 233                         {
 234                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
 235                                 dev->eccUnfixed++;
 236                         }
 237
 238                         if(eccResult2>0)
 239                         {
 240                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
 241                                 dev->eccFixed++;
 242                         }
 243                         else if(eccResult2<0)
 244                         {
 245                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
 246                                 dev->eccUnfixed++;
 247                         }
 248
 249                         if(eccResult1 || eccResult2)
 250                         {
 251                                 // Hoosterman, we had a data problem on this page
 252                                 yaffs_HandleReadDataError(dev,chunkInNAND);
 253                         }
 254
 255                         if(eccResult1 < 0 || eccResult2 < 0)
 256                                 *eccResult = YAFFS_ECC_RESULT_UNFIXED;
 257                         else if(eccResult1 > 0 || eccResult2 > 0)
 258                                 *eccResult = YAFFS_ECC_RESULT_FIXED;
 259                         else
 260                                 *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 261                 }
 262         }
 263         else
 264         {
 265         // Must allocate enough memory for spare+2*sizeof(int) for ecc results from device.
 266         struct yaffs_NANDSpare nspare;
 267                 retVal  = dev->readChunkFromNAND(dev,chunkInNAND,data,(yaffs_Spare*)&nspare);
 268                 memcpy (spare, &nspare, sizeof(yaffs_Spare));
 269                 if(data && doErrorCorrection)
 270                 {
 271                         if(nspare.eccres1>0)
 272                         {
 273                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
 274                         }
 275                         else if(nspare.eccres1<0)
 276                         {
 277                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
 278                         }
 279
 280                         if(nspare.eccres2>0)
 281                         {
 282                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
 283                         }
 284                         else if(nspare.eccres2<0)
 285                         {
 286                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
 287                         }
 288
 289                         if(nspare.eccres1 || nspare.eccres2)
 290                         {
 291                                 // Hoosterman, we had a data problem on this page
 292                                 yaffs_HandleReadDataError(dev,chunkInNAND);
 293                         }
 294
 295                         if(nspare.eccres1 < 0 || nspare.eccres2 < 0)
 296                                 *eccResult = YAFFS_ECC_RESULT_UNFIXED;
 297                         else if(nspare.eccres1 > 0 || nspare.eccres2 > 0)
 298                                 *eccResult = YAFFS_ECC_RESULT_FIXED;
 299                         else
 300                                 *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 301
 302
 303                 }
 304         }
 305         return retVal;
 306 }
 307
 308
 309
 310 static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,int chunkInNAND)
 311 {
 312
 313         static int init = 0;
 314         static __u8 cmpbuf[YAFFS_BYTES_PER_CHUNK];
 315         static __u8 data[YAFFS_BYTES_PER_CHUNK];
 316     // Might as well always allocate the larger size for dev->useNANDECC == true;
 317         static __u8 spare[sizeof(struct yaffs_NANDSpare)];
 318
 319         dev->readChunkFromNAND(dev,chunkInNAND,data,(yaffs_Spare *)spare);
 320
 321         if(!init)
 322         {
 323                 memset(cmpbuf,0xff,YAFFS_BYTES_PER_CHUNK);
 324                 init = 1;
 325         }
 326
 327         if(memcmp(cmpbuf,data,YAFFS_BYTES_PER_CHUNK)) return  YAFFS_FAIL;
 328         if(memcmp(cmpbuf,spare,16)) return YAFFS_FAIL;
 329
 330
 331         return YAFFS_OK;
 332
 333 }
 334
 335
 336 #if 0
 337 int yaffs_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,int blockInNAND)
 338 {
 339         dev->nBlockErasures++;
 340         return dev->eraseBlockInNAND(dev,blockInNAND);
 341 }
 342
 343 int yaffs_InitialiseNAND(struct yaffs_DeviceStruct *dev)
 344 {
 345         return dev->initialiseNAND(dev);
 346 }
 347
 348 #endif
 349
 350 #if 0
 351 static int yaffs_WriteNewChunkToNAND(struct yaffs_DeviceStruct *dev, const __u8 *data, yaffs_Spare *spare,int useReserve)
 352 {
 353         int chunk;
 354
 355         int writeOk = 1;
 356         int attempts = 0;
 357
 358         unsigned char rbData[YAFFS_BYTES_PER_CHUNK];
 359         yaffs_Spare rbSpare;
 360
 361         do{
 362                 chunk = yaffs_AllocateChunk(dev,useReserve);
 363
 364                 if(chunk >= 0)
 365                 {
 366
 367                         // First check this chunk is erased...
 368 #ifndef CONFIG_YAFFS_DISABLE_CHUNK_ERASED_CHECK
 369                         writeOk = yaffs_CheckChunkErased(dev,chunk);
 370 #endif
 371                         if(!writeOk)
 372                         {
 373                                 T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs chunk %d was not erased" TENDSTR),chunk));
 374                         }
 375                         else
 376                         {
 377                                 writeOk =  yaffs_WriteChunkToNAND(dev,chunk,data,spare);
 378                         }
 379                         attempts++;
 380                         if(writeOk)
 381                         {
 382                                 // Readback & verify
 383                                 // If verify fails, then delete this chunk and try again
 384                                 // To verify we compare everything except the block and
 385                                 // page status bytes.
 386                                 // NB We check a raw read without ECC correction applied
 387                                 yaffs_ReadChunkFromNAND(dev,chunk,rbData,&rbSpare,0);
 388
 389 #ifndef CONFIG_YAFFS_DISABLE_WRITE_VERIFY
 390                                 if(!yaffs_VerifyCompare(data,rbData,spare,&rbSpare))
 391                                 {
 392                                         // Didn't verify
 393                                         T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs write verify failed on chunk %d" TENDSTR), chunk));
 394
 395                                         writeOk = 0;
 396                                 }
 397 #endif
 398
 399                         }
 400                         if(writeOk)
 401                         {
 402                                 // Copy the data into the write buffer.
 403                                 // NB We do this at the end to prevent duplicates in the case of a write error.
 404                                 //Todo
 405                                 yaffs_HandleWriteChunkOk(dev,chunk,data,spare);
 406                         }
 407                         else
 408                         {
 409                                 yaffs_HandleWriteChunkError(dev,chunk);
 410                         }
 411                 }
 412
 413         } while(chunk >= 0 && ! writeOk);
 414
 415         if(attempts > 1)
 416         {
 417                 T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs write required %d attempts" TENDSTR),attempts));
 418                 dev->nRetriedWrites+= (attempts - 1);
 419         }
 420
 421         return chunk;
 422 }
 423
 424 #endif
 425
 426 ///
 427 // Functions for robustisizing
 428 //
 429 //
 430 #if 0
 431
 432 static void yaffs_RetireBlock(yaffs_Device *dev,int blockInNAND)
 433 {
 434         // Ding the blockStatus in the first two pages of the block.
 435
 436         yaffs_Spare spare;
 437
 438         memset(&spare, 0xff,sizeof(yaffs_Spare));
 439
 440         spare.blockStatus = 0;
 441
 442         // TODO change this retirement marking for other NAND types
 443         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock, NULL , &spare);
 444         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock + 1, NULL , &spare);
 445
 446         yaffs_GetBlockInfo(dev,blockInNAND)->blockState = YAFFS_BLOCK_STATE_DEAD;
 447         dev->nRetiredBlocks++;
 448 }
 449
 450 #endif
 451
 452 #if 0
 453 static int yaffs_RewriteBufferedBlock(yaffs_Device *dev)
 454 {
 455         dev->doingBufferedBlockRewrite = 1;
 456         //
 457         //      Remove erased chunks
 458         //  Rewrite existing chunks to a new block
 459         //      Set current write block to the new block
 460
 461         dev->doingBufferedBlockRewrite = 0;
 462
 463         return 1;
 464 }
 465
 466 #endif
 467
 468 static void yaffs_HandleReadDataError(yaffs_Device *dev,int chunkInNAND)
 469 {
 470         int blockInNAND = chunkInNAND/dev->nChunksPerBlock;
 471
 472         // Mark the block for retirement
 473         yaffs_GetBlockInfo(dev,blockInNAND)->needsRetiring = 1;
 474         T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,(TSTR("**>>Block %d marked for retirement" TENDSTR),blockInNAND));
 475
 476
 477         //TODO
 478         // Just do a garbage collection on the affected block then retire the block
 479         // NB recursion
 480 }
 481
 482
 483 static void yaffs_CheckWrittenBlock(yaffs_Device *dev,int chunkInNAND)
 484 {
 485 }
 486
 487 static void yaffs_HandleWriteChunkOk(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare)
 488 {
 489 }
 490
 491 static void yaffs_HandleUpdateChunk(yaffs_Device *dev,int chunkInNAND, const yaffs_Spare *spare)
 492 {
 493 }
 494
 495 static void yaffs_HandleWriteChunkError(yaffs_Device *dev,int chunkInNAND)
 496 {
 497         int blockInNAND = chunkInNAND/dev->nChunksPerBlock;
 498
 499         // Mark the block for retirement
 500         yaffs_GetBlockInfo(dev,blockInNAND)->needsRetiring = 1;
 501         // Delete the chunk
 502         yaffs_DeleteChunk(dev,chunkInNAND,1,__LINE__);
 503 }
 504
 505
 506
 507
 508 static int yaffs_VerifyCompare(const __u8 *d0, const __u8 * d1, const yaffs_Spare *s0, const yaffs_Spare *s1)
 509 {
 510
 511
 512         if( memcmp(d0,d1,YAFFS_BYTES_PER_CHUNK) != 0 ||
 513                 s0->tagByte0 != s1->tagByte0 ||
 514                 s0->tagByte1 != s1->tagByte1 ||
 515                 s0->tagByte2 != s1->tagByte2 ||
 516                 s0->tagByte3 != s1->tagByte3 ||
 517                 s0->tagByte4 != s1->tagByte4 ||
 518                 s0->tagByte5 != s1->tagByte5 ||
 519                 s0->tagByte6 != s1->tagByte6 ||
 520                 s0->tagByte7 != s1->tagByte7 ||
 521                 s0->ecc1[0]  != s1->ecc1[0]  ||
 522                 s0->ecc1[1]  != s1->ecc1[1]  ||
 523                 s0->ecc1[2]  != s1->ecc1[2]  ||
 524                 s0->ecc2[0]  != s1->ecc2[0]  ||
 525                 s0->ecc2[1]  != s1->ecc2[1]  ||
 526                 s0->ecc2[2]  != s1->ecc2[2] )
 527                 {
 528                         return 0;
 529                 }
 530
 531         return 1;
 532 }
 533
 534 #if 0
 535 typedef struct
 536 {
 537
 538         unsigned validMarker0;
 539         unsigned chunkUsed;                 //  Status of the chunk: used or unused
 540         unsigned objectId;                      // If 0 then this is not part of an object (unused)
 541         unsigned chunkId;                       // If 0 then this is a header
 542         unsigned byteCount;                 // Only valid for data chunks
 543         // The following stuff only has meaning when we read
 544         yaffs_ECCResult eccResult;  // Only valid when we read.
 545         unsigned blockBad;                      // Only valid on reading
 546
 547         // YAFFS 1 stuff
 548         unsigned chunkDeleted;          // The chunk is marked deleted
 549         unsigned serialNumber;          // Yaffs1 2-bit serial number
 550
 551         // YAFFS2 stuff
 552         unsigned sequenceNumber;        // The sequence number of this block
 553
 554         unsigned validMarker1;
 555
 556 } yaffs_ExtendedTags;
 557
 558
 559 typedef struct
 560 {
 561     unsigned chunkId:20;
 562     unsigned serialNumber:2;
 563     unsigned byteCount:10;
 564     unsigned objectId:18;
 565     unsigned ecc:12;
 566     unsigned unusedStuff:2;
 567 } yaffs_Tags;
 568
 569
 570 #endif
 571
 572 int yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_ExtendedTags *eTags)
 573 {
 574         yaffs_Spare spare;
 575         yaffs_Tags tags;
 576
 577         yaffs_SpareInitialise(&spare);
 578
 579         if(eTags->chunkDeleted)
 580         {
 581                 spare.pageStatus = 0;
 582         }
 583         else
 584         {
 585                 tags.objectId = eTags->objectId;
 586                 tags.chunkId = eTags->chunkId;
 587                 tags.byteCount = eTags->byteCount;
 588                 tags.serialNumber = eTags->serialNumber;
 589
 590                  yaffs_LoadTagsIntoSpare(&spare,&tags);
 591
 592         }
 593
 594         return yaffs_WriteChunkToNAND(dev,chunkInNAND,data,&spare);
 595 }
 596
 597
 598 int yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *eTags)
 599 {
 600
 601         yaffs_Spare spare;
 602         yaffs_Tags tags;
 603         yaffs_ECCResult eccResult;
 604
 605         if(yaffs_ReadChunkFromNAND(dev,chunkInNAND,data,&spare,&eccResult,1))
 606         {
 607                  int deleted = (yaffs_CountBits(spare.pageStatus) < 7) ? 1 : 0;
 608
 609                  yaffs_GetTagsFromSpare(dev,&spare,&tags);
 610
 611                  eTags->chunkDeleted = deleted;
 612                  eTags->objectId = tags.objectId;
 613                  eTags->chunkId = tags.chunkId;
 614                  eTags->byteCount = tags.byteCount;
 615                  eTags->serialNumber = tags.serialNumber;
 616                  eTags->eccResult = eccResult;
 617                  eTags->blockBad = 0; // We're reading it therefore it is not a bad block
 618
 619                  return YAFFS_OK;
 620         }
 621         else
 622         {
 623                 return YAFFS_FAIL;
 624         }
 625 }
 626
 627 int yaffs_TagsCompatabilityMarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockInNAND)
 628 {
 629
 630         yaffs_Spare spare;
 631
 632         memset(&spare, 0xff,sizeof(yaffs_Spare));
 633
 634         spare.blockStatus = 0;
 635
 636         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock, NULL , &spare);
 637         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock + 1, NULL , &spare);
 638
 639         return YAFFS_OK;
 640
 641 }
 642
 643
 644 int yaffs_TagsCompatabilityQueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo, yaffs_BlockState *state, int *sequenceNumber)
 645 {
 646
 647      yaffs_Spare spare0,spare1;
 648      static yaffs_Spare spareFF;
 649      static int init;
 650      yaffs_ECCResult dummy;
 651
 652      if(!init)
 653      {
 654              memset(&spareFF,0xFF,sizeof(spareFF));
 655              init = 1;
 656      }
 657
 658      *sequenceNumber = 0;
 659
 660      yaffs_ReadChunkFromNAND(dev,blockNo * dev->nChunksPerBlock,NULL,&spare0,&dummy,1);
 661      yaffs_ReadChunkFromNAND(dev,blockNo * dev->nChunksPerBlock + 1,NULL,&spare1,&dummy,1);
 662
 663      if(yaffs_CountBits(spare0.blockStatus & spare1.blockStatus) < 7)
 664         *state = YAFFS_BLOCK_STATE_DEAD;
 665      else if(memcmp(&spareFF,&spare0,sizeof(spareFF)) == 0)
 666          *state = YAFFS_BLOCK_STATE_EMPTY;
 667      else
 668          *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 669
 670      return YAFFS_OK;
 671 }
 672