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 1.3 2005-07-31 06:47:12 marty 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 #ifdef NOTYET
  22 static void yaffs_CheckWrittenBlock(yaffs_Device *dev,int chunkInNAND);
  23 static void yaffs_HandleWriteChunkOk(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare);
  24 static void yaffs_HandleUpdateChunk(yaffs_Device *dev,int chunkInNAND, const yaffs_Spare *spare);
  25 static void yaffs_HandleWriteChunkError(yaffs_Device *dev,int chunkInNAND);
  26 #endif
  27
  28
  29 static const char yaffs_countBitsTable[256] =
  30 {
  31 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4,
  32 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  33 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  34 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  35 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  36 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  37 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  38 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  39 1,2,2,3,2,3,3,4,2,3,3,4,3,4,4,5,
  40 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  41 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  42 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  43 2,3,3,4,3,4,4,5,3,4,4,5,4,5,5,6,
  44 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  45 3,4,4,5,4,5,5,6,4,5,5,6,5,6,6,7,
  46 4,5,5,6,5,6,6,7,5,6,6,7,6,7,7,8
  47 };
  48
  49 static int yaffs_CountBits(__u8 x)
  50 {
  51         int retVal;
  52         retVal = yaffs_countBitsTable[x];
  53         return retVal;
  54 }
  55
  56
  57 /////////////// Tags ECC calculations ///////////////////
  58
  59 void yaffs_CalcECC(const __u8 *data, yaffs_Spare *spare)
  60 {
  61         yaffs_ECCCalculate(data , spare->ecc1);
  62         yaffs_ECCCalculate(&data[256] , spare->ecc2);
  63 }
  64
  65 void yaffs_CalcTagsECC(yaffs_Tags *tags)
  66 {
  67         // Calculate an ecc
  68
  69         unsigned char *b = ((yaffs_TagsUnion *)tags)->asBytes;
  70         unsigned  i,j;
  71         unsigned  ecc = 0;
  72         unsigned bit = 0;
  73
  74         tags->ecc = 0;
  75
  76         for(i = 0; i < 8; i++)
  77         {
  78                 for(j = 1; j &0xff; j<<=1)
  79                 {
  80                         bit++;
  81                         if(b[i] & j)
  82                         {
  83                                 ecc ^= bit;
  84                         }
  85                 }
  86         }
  87
  88         tags->ecc = ecc;
  89
  90
  91 }
  92
  93 int  yaffs_CheckECCOnTags(yaffs_Tags *tags)
  94 {
  95         unsigned ecc = tags->ecc;
  96
  97         yaffs_CalcTagsECC(tags);
  98
  99         ecc ^= tags->ecc;
 100
 101         if(ecc && ecc <= 64)
 102         {
 103                 // TODO: Handle the failure better. Retire?
 104                 unsigned char *b = ((yaffs_TagsUnion *)tags)->asBytes;
 105
 106                 ecc--;
 107
 108                 b[ecc / 8] ^= (1 << (ecc & 7));
 109
 110                 // Now recvalc the ecc
 111                 yaffs_CalcTagsECC(tags);
 112
 113                 return 1; // recovered error
 114         }
 115         else if(ecc)
 116         {
 117                 // Wierd ecc failure value
 118                 // TODO Need to do somethiong here
 119                 return -1; //unrecovered error
 120         }
 121
 122         return 0;
 123 }
 124
 125 //////////////////////////// Tags ///////////////////////////////////////
 126
 127 static void yaffs_LoadTagsIntoSpare(yaffs_Spare *sparePtr, yaffs_Tags *tagsPtr)
 128 {
 129         yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
 130
 131         yaffs_CalcTagsECC(tagsPtr);
 132
 133         sparePtr->tagByte0 = tu->asBytes[0];
 134         sparePtr->tagByte1 = tu->asBytes[1];
 135         sparePtr->tagByte2 = tu->asBytes[2];
 136         sparePtr->tagByte3 = tu->asBytes[3];
 137         sparePtr->tagByte4 = tu->asBytes[4];
 138         sparePtr->tagByte5 = tu->asBytes[5];
 139         sparePtr->tagByte6 = tu->asBytes[6];
 140         sparePtr->tagByte7 = tu->asBytes[7];
 141 }
 142
 143 static void yaffs_GetTagsFromSpare(yaffs_Device *dev, yaffs_Spare *sparePtr,yaffs_Tags *tagsPtr)
 144 {
 145         yaffs_TagsUnion *tu = (yaffs_TagsUnion *)tagsPtr;
 146         int result;
 147
 148         tu->asBytes[0]= sparePtr->tagByte0;
 149         tu->asBytes[1]= sparePtr->tagByte1;
 150         tu->asBytes[2]= sparePtr->tagByte2;
 151         tu->asBytes[3]= sparePtr->tagByte3;
 152         tu->asBytes[4]= sparePtr->tagByte4;
 153         tu->asBytes[5]= sparePtr->tagByte5;
 154         tu->asBytes[6]= sparePtr->tagByte6;
 155         tu->asBytes[7]= sparePtr->tagByte7;
 156
 157         result =  yaffs_CheckECCOnTags(tagsPtr);
 158         if(result> 0)
 159         {
 160                 dev->tagsEccFixed++;
 161         }
 162         else if(result <0)
 163         {
 164                 dev->tagsEccUnfixed++;
 165         }
 166 }
 167
 168 static void yaffs_SpareInitialise(yaffs_Spare *spare)
 169 {
 170         memset(spare,0xFF,sizeof(yaffs_Spare));
 171 }
 172
 173
 174
 175
 176 static int yaffs_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,int chunkInNAND, const __u8 *data, yaffs_Spare *spare)
 177 {
 178         if(chunkInNAND < dev->startBlock * dev->nChunksPerBlock)
 179         {
 180                 T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs chunk %d is not valid" TENDSTR),chunkInNAND));
 181                 return YAFFS_FAIL;
 182         }
 183
 184         dev->nPageWrites++;
 185         return dev->writeChunkToNAND(dev,chunkInNAND,data,spare);
 186 }
 187
 188
 189
 190 static int yaffs_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,
 191                                                         int chunkInNAND,
 192                                                         __u8 *data,
 193                                                         yaffs_Spare *spare,
 194                                                         yaffs_ECCResult *eccResult,
 195                                                         int doErrorCorrection)
 196 {
 197         int retVal;
 198         yaffs_Spare localSpare;
 199
 200         dev->nPageReads++;
 201
 202
 203
 204
 205         if(!spare && data)
 206         {
 207                 // If we don't have a real spare, then we use a local one.
 208                 // Need this for the calculation of the ecc
 209                 spare = &localSpare;
 210         }
 211
 212
 213         if(!dev->useNANDECC)
 214         {
 215                 retVal  = dev->readChunkFromNAND(dev,chunkInNAND,data,spare);
 216                 if(data && doErrorCorrection)
 217                 {
 218                         // Do ECC correction
 219                         //Todo handle any errors
 220                 int eccResult1,eccResult2;
 221                 __u8 calcEcc[3];
 222
 223                         yaffs_ECCCalculate(data,calcEcc);
 224                         eccResult1 = yaffs_ECCCorrect (data,spare->ecc1, calcEcc);
 225                         yaffs_ECCCalculate(&data[256],calcEcc);
 226                         eccResult2 = yaffs_ECCCorrect(&data[256],spare->ecc2, calcEcc);
 227
 228                         if(eccResult1>0)
 229                         {
 230                                 T(YAFFS_TRACE_ERROR, (TSTR("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
 231                                 dev->eccFixed++;
 232                         }
 233                         else if(eccResult1<0)
 234                         {
 235                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
 236                                 dev->eccUnfixed++;
 237                         }
 238
 239                         if(eccResult2>0)
 240                         {
 241                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
 242                                 dev->eccFixed++;
 243                         }
 244                         else if(eccResult2<0)
 245                         {
 246                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
 247                                 dev->eccUnfixed++;
 248                         }
 249
 250                         if(eccResult1 || eccResult2)
 251                         {
 252                                 // Hoosterman, we had a data problem on this page
 253                                 yaffs_HandleReadDataError(dev,chunkInNAND);
 254                         }
 255
 256                         if(eccResult1 < 0 || eccResult2 < 0)
 257                                 *eccResult = YAFFS_ECC_RESULT_UNFIXED;
 258                         else if(eccResult1 > 0 || eccResult2 > 0)
 259                                 *eccResult = YAFFS_ECC_RESULT_FIXED;
 260                         else
 261                                 *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 262                 }
 263         }
 264         else
 265         {
 266         // Must allocate enough memory for spare+2*sizeof(int) for ecc results from device.
 267         struct yaffs_NANDSpare nspare;
 268                 retVal  = dev->readChunkFromNAND(dev,chunkInNAND,data,(yaffs_Spare*)&nspare);
 269                 memcpy (spare, &nspare, sizeof(yaffs_Spare));
 270                 if(data && doErrorCorrection)
 271                 {
 272                         if(nspare.eccres1>0)
 273                         {
 274                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
 275                         }
 276                         else if(nspare.eccres1<0)
 277                         {
 278                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
 279                         }
 280
 281                         if(nspare.eccres2>0)
 282                         {
 283                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
 284                         }
 285                         else if(nspare.eccres2<0)
 286                         {
 287                                 T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
 288                         }
 289
 290                         if(nspare.eccres1 || nspare.eccres2)
 291                         {
 292                                 // Hoosterman, we had a data problem on this page
 293                                 yaffs_HandleReadDataError(dev,chunkInNAND);
 294                         }
 295
 296                         if(nspare.eccres1 < 0 || nspare.eccres2 < 0)
 297                                 *eccResult = YAFFS_ECC_RESULT_UNFIXED;
 298                         else if(nspare.eccres1 > 0 || nspare.eccres2 > 0)
 299                                 *eccResult = YAFFS_ECC_RESULT_FIXED;
 300                         else
 301                                 *eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 302
 303
 304                 }
 305         }
 306         return retVal;
 307 }
 308
 309 #ifdef NOTYET
 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 #endif
 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 #ifdef NOTYET
 484 static void yaffs_CheckWrittenBlock(yaffs_Device *dev,int chunkInNAND)
 485 {
 486 }
 487
 488 static void yaffs_HandleWriteChunkOk(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_Spare *spare)
 489 {
 490 }
 491
 492 static void yaffs_HandleUpdateChunk(yaffs_Device *dev,int chunkInNAND, const yaffs_Spare *spare)
 493 {
 494 }
 495
 496 static void yaffs_HandleWriteChunkError(yaffs_Device *dev,int chunkInNAND)
 497 {
 498         int blockInNAND = chunkInNAND/dev->nChunksPerBlock;
 499
 500         // Mark the block for retirement
 501         yaffs_GetBlockInfo(dev,blockInNAND)->needsRetiring = 1;
 502         // Delete the chunk
 503         yaffs_DeleteChunk(dev,chunkInNAND,1,__LINE__);
 504 }
 505
 506
 507
 508
 509 static int yaffs_VerifyCompare(const __u8 *d0, const __u8 * d1, const yaffs_Spare *s0, const yaffs_Spare *s1)
 510 {
 511
 512
 513         if( memcmp(d0,d1,YAFFS_BYTES_PER_CHUNK) != 0 ||
 514                 s0->tagByte0 != s1->tagByte0 ||
 515                 s0->tagByte1 != s1->tagByte1 ||
 516                 s0->tagByte2 != s1->tagByte2 ||
 517                 s0->tagByte3 != s1->tagByte3 ||
 518                 s0->tagByte4 != s1->tagByte4 ||
 519                 s0->tagByte5 != s1->tagByte5 ||
 520                 s0->tagByte6 != s1->tagByte6 ||
 521                 s0->tagByte7 != s1->tagByte7 ||
 522                 s0->ecc1[0]  != s1->ecc1[0]  ||
 523                 s0->ecc1[1]  != s1->ecc1[1]  ||
 524                 s0->ecc1[2]  != s1->ecc1[2]  ||
 525                 s0->ecc2[0]  != s1->ecc2[0]  ||
 526                 s0->ecc2[1]  != s1->ecc2[1]  ||
 527                 s0->ecc2[2]  != s1->ecc2[2] )
 528                 {
 529                         return 0;
 530                 }
 531
 532         return 1;
 533 }
 534 #endif /* NOTYET */
 535
 536 #if 0
 537 typedef struct
 538 {
 539
 540         unsigned validMarker0;
 541         unsigned chunkUsed;                 //  Status of the chunk: used or unused
 542         unsigned objectId;                      // If 0 then this is not part of an object (unused)
 543         unsigned chunkId;                       // If 0 then this is a header
 544         unsigned byteCount;                 // Only valid for data chunks
 545         // The following stuff only has meaning when we read
 546         yaffs_ECCResult eccResult;  // Only valid when we read.
 547         unsigned blockBad;                      // Only valid on reading
 548
 549         // YAFFS 1 stuff
 550         unsigned chunkDeleted;          // The chunk is marked deleted
 551         unsigned serialNumber;          // Yaffs1 2-bit serial number
 552
 553         // YAFFS2 stuff
 554         unsigned sequenceNumber;        // The sequence number of this block
 555
 556         unsigned validMarker1;
 557
 558 } yaffs_ExtendedTags;
 559
 560
 561 typedef struct
 562 {
 563     unsigned chunkId:20;
 564     unsigned serialNumber:2;
 565     unsigned byteCount:10;
 566     unsigned objectId:18;
 567     unsigned ecc:12;
 568     unsigned unusedStuff:2;
 569 } yaffs_Tags;
 570
 571
 572 #endif
 573
 574 int yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(yaffs_Device *dev,int chunkInNAND,const __u8 *data, const yaffs_ExtendedTags *eTags)
 575 {
 576         yaffs_Spare spare;
 577         yaffs_Tags tags;
 578
 579         yaffs_SpareInitialise(&spare);
 580
 581         if(eTags->chunkDeleted)
 582         {
 583                 spare.pageStatus = 0;
 584         }
 585         else
 586         {
 587                 tags.objectId = eTags->objectId;
 588                 tags.chunkId = eTags->chunkId;
 589                 tags.byteCount = eTags->byteCount;
 590                 tags.serialNumber = eTags->serialNumber;
 591
 592 // NCB
 593                 if (!dev->useNANDECC && data)
 594                 {
 595                     yaffs_CalcECC(data,&spare);
 596                 }
 597
 598 // /NCB
 599                  yaffs_LoadTagsIntoSpare(&spare,&tags);
 600
 601         }
 602
 603         return yaffs_WriteChunkToNAND(dev,chunkInNAND,data,&spare);
 604 }
 605
 606
 607 int yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(yaffs_Device *dev,int chunkInNAND, __u8 *data, yaffs_ExtendedTags *eTags)
 608 {
 609
 610         yaffs_Spare spare;
 611         yaffs_Tags tags;
 612         yaffs_ECCResult eccResult;
 613
 614 // NCB
 615      static yaffs_Spare spareFF;
 616      static int init;
 617
 618      if(!init)
 619      {
 620              memset(&spareFF,0xFF,sizeof(spareFF));
 621              init = 1;
 622      }
 623 // /NCB
 624         if(yaffs_ReadChunkFromNAND(dev,chunkInNAND,data,&spare,&eccResult,1))
 625         {
 626 // added NCB - eTags may be NULL
 627                 if (eTags) {
 628
 629                  int deleted = (yaffs_CountBits(spare.pageStatus) < 7) ? 1 : 0;
 630
 631                  yaffs_GetTagsFromSpare(dev,&spare,&tags);
 632
 633                  eTags->chunkDeleted = deleted;
 634                  eTags->objectId = tags.objectId;
 635                  eTags->chunkId = tags.chunkId;
 636                  eTags->byteCount = tags.byteCount;
 637                  eTags->serialNumber = tags.serialNumber;
 638                  eTags->eccResult = eccResult;
 639                  eTags->blockBad = 0; // We're reading it therefore it is not a bad block
 640
 641 // NCB added 18/2/2005
 642                  eTags->chunkUsed = (memcmp(&spareFF,&spare,sizeof(spareFF)) != 0) ? 1:0;
 643                 }
 644
 645                  return YAFFS_OK;
 646         }
 647         else
 648         {
 649                 return YAFFS_FAIL;
 650         }
 651 }
 652
 653 int yaffs_TagsCompatabilityMarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockInNAND)
 654 {
 655
 656         yaffs_Spare spare;
 657
 658         memset(&spare, 0xff,sizeof(yaffs_Spare));
 659
 660         spare.blockStatus = 0;
 661
 662         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock, NULL , &spare);
 663         yaffs_WriteChunkToNAND(dev, blockInNAND * dev->nChunksPerBlock + 1, NULL , &spare);
 664
 665         return YAFFS_OK;
 666
 667 }
 668
 669
 670 int yaffs_TagsCompatabilityQueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo, yaffs_BlockState *state, int *sequenceNumber)
 671 {
 672
 673      yaffs_Spare spare0,spare1;
 674      static yaffs_Spare spareFF;
 675      static int init;
 676      yaffs_ECCResult dummy;
 677
 678      if(!init)
 679      {
 680              memset(&spareFF,0xFF,sizeof(spareFF));
 681              init = 1;
 682      }
 683
 684      *sequenceNumber = 0;
 685
 686      yaffs_ReadChunkFromNAND(dev,blockNo * dev->nChunksPerBlock,NULL,&spare0,&dummy,1);
 687      yaffs_ReadChunkFromNAND(dev,blockNo * dev->nChunksPerBlock + 1,NULL,&spare1,&dummy,1);
 688
 689      if(yaffs_CountBits(spare0.blockStatus & spare1.blockStatus) < 7)
 690         *state = YAFFS_BLOCK_STATE_DEAD;
 691      else if(memcmp(&spareFF,&spare0,sizeof(spareFF)) == 0)
 692          *state = YAFFS_BLOCK_STATE_EMPTY;
 693      else
 694          *state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
 695
 696      return YAFFS_OK;
 697 }
 698