target/linux/generic-2.6/files-2.6.23/fs/yaffs2/yaffs_packedtags2.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2007 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   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
  14 #include "yaffs_packedtags2.h"
  15 #include "yportenv.h"
  16 #include "yaffs_tagsvalidity.h"
  17
  18 /* This code packs a set of extended tags into a binary structure for
  19  * NAND storage
  20  */
  21
  22 /* Some of the information is "extra" struff which can be packed in to
  23  * speed scanning
  24  * This is defined by having the EXTRA_HEADER_INFO_FLAG set.
  25  */
  26
  27 /* Extra flags applied to chunkId */
  28
  29 #define EXTRA_HEADER_INFO_FLAG  0x80000000
  30 #define EXTRA_SHRINK_FLAG       0x40000000
  31 #define EXTRA_SHADOWS_FLAG      0x20000000
  32 #define EXTRA_SPARE_FLAGS       0x10000000
  33
  34 #define ALL_EXTRA_FLAGS         0xF0000000
  35
  36 /* Also, the top 4 bits of the object Id are set to the object type. */
  37 #define EXTRA_OBJECT_TYPE_SHIFT (28)
  38 #define EXTRA_OBJECT_TYPE_MASK  ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT)
  39
  40 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 * pt)
  41 {
  42         T(YAFFS_TRACE_MTD,
  43           (TSTR("packed tags obj %d chunk %d byte %d seq %d" TENDSTR),
  44            pt->t.objectId, pt->t.chunkId, pt->t.byteCount,
  45            pt->t.sequenceNumber));
  46 }
  47
  48 static void yaffs_DumpTags2(const yaffs_ExtendedTags * t)
  49 {
  50         T(YAFFS_TRACE_MTD,
  51           (TSTR
  52            ("ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte "
  53             "%d del %d ser %d seq %d"
  54             TENDSTR), t->eccResult, t->blockBad, t->chunkUsed, t->objectId,
  55            t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber,
  56            t->sequenceNumber));
  57
  58 }
  59
  60 void yaffs_PackTags2(yaffs_PackedTags2 * pt, const yaffs_ExtendedTags * t)
  61 {
  62         pt->t.chunkId = t->chunkId;
  63         pt->t.sequenceNumber = t->sequenceNumber;
  64         pt->t.byteCount = t->byteCount;
  65         pt->t.objectId = t->objectId;
  66
  67         if (t->chunkId == 0 && t->extraHeaderInfoAvailable) {
  68                 /* Store the extra header info instead */
  69                 /* We save the parent object in the chunkId */
  70                 pt->t.chunkId = EXTRA_HEADER_INFO_FLAG
  71                         | t->extraParentObjectId;
  72                 if (t->extraIsShrinkHeader) {
  73                         pt->t.chunkId |= EXTRA_SHRINK_FLAG;
  74                 }
  75                 if (t->extraShadows) {
  76                         pt->t.chunkId |= EXTRA_SHADOWS_FLAG;
  77                 }
  78
  79                 pt->t.objectId &= ~EXTRA_OBJECT_TYPE_MASK;
  80                 pt->t.objectId |=
  81                     (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
  82
  83                 if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
  84                         pt->t.byteCount = t->extraEquivalentObjectId;
  85                 } else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE) {
  86                         pt->t.byteCount = t->extraFileLength;
  87                 } else {
  88                         pt->t.byteCount = 0;
  89                 }
  90         }
  91
  92         yaffs_DumpPackedTags2(pt);
  93         yaffs_DumpTags2(t);
  94
  95 #ifndef YAFFS_IGNORE_TAGS_ECC
  96         {
  97                 yaffs_ECCCalculateOther((unsigned char *)&pt->t,
  98                                         sizeof(yaffs_PackedTags2TagsPart),
  99                                         &pt->ecc);
 100         }
 101 #endif
 102 }
 103
 104 void yaffs_UnpackTags2(yaffs_ExtendedTags * t, yaffs_PackedTags2 * pt)
 105 {
 106
 107         memset(t, 0, sizeof(yaffs_ExtendedTags));
 108
 109         yaffs_InitialiseTags(t);
 110
 111         if (pt->t.sequenceNumber != 0xFFFFFFFF) {
 112                 /* Page is in use */
 113 #ifdef YAFFS_IGNORE_TAGS_ECC
 114                 {
 115                         t->eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 116                 }
 117 #else
 118                 {
 119                         yaffs_ECCOther ecc;
 120                         int result;
 121                         yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 122                                                 sizeof
 123                                                 (yaffs_PackedTags2TagsPart),
 124                                                 &ecc);
 125                         result =
 126                             yaffs_ECCCorrectOther((unsigned char *)&pt->t,
 127                                                   sizeof
 128                                                   (yaffs_PackedTags2TagsPart),
 129                                                   &pt->ecc, &ecc);
 130                         switch(result){
 131                                 case 0:
 132                                         t->eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 133                                         break;
 134                                 case 1:
 135                                         t->eccResult = YAFFS_ECC_RESULT_FIXED;
 136                                         break;
 137                                 case -1:
 138                                         t->eccResult = YAFFS_ECC_RESULT_UNFIXED;
 139                                         break;
 140                                 default:
 141                                         t->eccResult = YAFFS_ECC_RESULT_UNKNOWN;
 142                         }
 143                 }
 144 #endif
 145                 t->blockBad = 0;
 146                 t->chunkUsed = 1;
 147                 t->objectId = pt->t.objectId;
 148                 t->chunkId = pt->t.chunkId;
 149                 t->byteCount = pt->t.byteCount;
 150                 t->chunkDeleted = 0;
 151                 t->serialNumber = 0;
 152                 t->sequenceNumber = pt->t.sequenceNumber;
 153
 154                 /* Do extra header info stuff */
 155
 156                 if (pt->t.chunkId & EXTRA_HEADER_INFO_FLAG) {
 157                         t->chunkId = 0;
 158                         t->byteCount = 0;
 159
 160                         t->extraHeaderInfoAvailable = 1;
 161                         t->extraParentObjectId =
 162                             pt->t.chunkId & (~(ALL_EXTRA_FLAGS));
 163                         t->extraIsShrinkHeader =
 164                             (pt->t.chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
 165                         t->extraShadows =
 166                             (pt->t.chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
 167                         t->extraObjectType =
 168                             pt->t.objectId >> EXTRA_OBJECT_TYPE_SHIFT;
 169                         t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
 170
 171                         if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
 172                                 t->extraEquivalentObjectId = pt->t.byteCount;
 173                         } else {
 174                                 t->extraFileLength = pt->t.byteCount;
 175                         }
 176                 }
 177         }
 178
 179         yaffs_DumpPackedTags2(pt);
 180         yaffs_DumpTags2(t);
 181
 182 }