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
  15 #include "yaffs_packedtags2.h"
  16 #include "yportenv.h"
  17 #include "yaffs_tagsvalidity.h"
  18
  19 /* This code packs a set of extended tags into a binary structure for
  20  * NAND storage
  21  */
  22
  23 /* Some of the information is "extra" struff which can be packed in to
  24  * speed scanning
  25  * This is defined by having the EXTRA_HEADER_INFO_FLAG set.
  26  */
  27
  28 /* Extra flags applied to chunkId */
  29
  30 #define EXTRA_HEADER_INFO_FLAG  0x80000000
  31 #define EXTRA_SHRINK_FLAG       0x40000000
  32 #define EXTRA_SHADOWS_FLAG      0x20000000
  33 #define EXTRA_SPARE_FLAGS       0x10000000
  34
  35 #define ALL_EXTRA_FLAGS         0xF0000000
  36
  37 /* Also, the top 4 bits of the object Id are set to the object type. */
  38 #define EXTRA_OBJECT_TYPE_SHIFT (28)
  39 #define EXTRA_OBJECT_TYPE_MASK  ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT)
  40
  41 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 * pt)
  42 {
  43         T(YAFFS_TRACE_MTD,
  44           (TSTR("packed tags obj %d chunk %d byte %d seq %d" TENDSTR),
  45            pt->t.objectId, pt->t.chunkId, pt->t.byteCount,
  46            pt->t.sequenceNumber));
  47 }
  48
  49 static void yaffs_DumpTags2(const yaffs_ExtendedTags * t)
  50 {
  51         T(YAFFS_TRACE_MTD,
  52           (TSTR
  53            ("ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte "
  54             "%d del %d ser %d seq %d"
  55             TENDSTR), t->eccResult, t->blockBad, t->chunkUsed, t->objectId,
  56            t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber,
  57            t->sequenceNumber));
  58
  59 }
  60
  61 void yaffs_PackTags2(yaffs_PackedTags2 * pt, const yaffs_ExtendedTags * t)
  62 {
  63         pt->t.chunkId = t->chunkId;
  64         pt->t.sequenceNumber = t->sequenceNumber;
  65         pt->t.byteCount = t->byteCount;
  66         pt->t.objectId = t->objectId;
  67
  68         if (t->chunkId == 0 && t->extraHeaderInfoAvailable) {
  69                 /* Store the extra header info instead */
  70                 /* We save the parent object in the chunkId */
  71                 pt->t.chunkId = EXTRA_HEADER_INFO_FLAG
  72                         | t->extraParentObjectId;
  73                 if (t->extraIsShrinkHeader) {
  74                         pt->t.chunkId |= EXTRA_SHRINK_FLAG;
  75                 }
  76                 if (t->extraShadows) {
  77                         pt->t.chunkId |= EXTRA_SHADOWS_FLAG;
  78                 }
  79
  80                 pt->t.objectId &= ~EXTRA_OBJECT_TYPE_MASK;
  81                 pt->t.objectId |=
  82                     (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
  83
  84                 if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
  85                         pt->t.byteCount = t->extraEquivalentObjectId;
  86                 } else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE) {
  87                         pt->t.byteCount = t->extraFileLength;
  88                 } else {
  89                         pt->t.byteCount = 0;
  90                 }
  91         }
  92
  93         yaffs_DumpPackedTags2(pt);
  94         yaffs_DumpTags2(t);
  95
  96 #ifndef YAFFS_IGNORE_TAGS_ECC
  97         {
  98                 yaffs_ECCCalculateOther((unsigned char *)&pt->t,
  99                                         sizeof(yaffs_PackedTags2TagsPart),
 100                                         &pt->ecc);
 101         }
 102 #endif
 103 }
 104
 105 void yaffs_UnpackTags2(yaffs_ExtendedTags * t, yaffs_PackedTags2 * pt)
 106 {
 107
 108         memset(t, 0, sizeof(yaffs_ExtendedTags));
 109
 110         yaffs_InitialiseTags(t);
 111
 112         if (pt->t.sequenceNumber != 0xFFFFFFFF) {
 113                 /* Page is in use */
 114 #ifdef YAFFS_IGNORE_TAGS_ECC
 115                 {
 116                         t->eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 117                 }
 118 #else
 119                 {
 120                         yaffs_ECCOther ecc;
 121                         int result;
 122                         yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 123                                                 sizeof
 124                                                 (yaffs_PackedTags2TagsPart),
 125                                                 &ecc);
 126                         result =
 127                             yaffs_ECCCorrectOther((unsigned char *)&pt->t,
 128                                                   sizeof
 129                                                   (yaffs_PackedTags2TagsPart),
 130                                                   &pt->ecc, &ecc);
 131                         switch(result){
 132                                 case 0:
 133                                         t->eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 134                                         break;
 135                                 case 1:
 136                                         t->eccResult = YAFFS_ECC_RESULT_FIXED;
 137                                         break;
 138                                 case -1:
 139                                         t->eccResult = YAFFS_ECC_RESULT_UNFIXED;
 140                                         break;
 141                                 default:
 142                                         t->eccResult = YAFFS_ECC_RESULT_UNKNOWN;
 143                         }
 144                 }
 145 #endif
 146                 t->blockBad = 0;
 147                 t->chunkUsed = 1;
 148                 t->objectId = pt->t.objectId;
 149                 t->chunkId = pt->t.chunkId;
 150                 t->byteCount = pt->t.byteCount;
 151                 t->chunkDeleted = 0;
 152                 t->serialNumber = 0;
 153                 t->sequenceNumber = pt->t.sequenceNumber;
 154
 155                 /* Do extra header info stuff */
 156
 157                 if (pt->t.chunkId & EXTRA_HEADER_INFO_FLAG) {
 158                         t->chunkId = 0;
 159                         t->byteCount = 0;
 160
 161                         t->extraHeaderInfoAvailable = 1;
 162                         t->extraParentObjectId =
 163                             pt->t.chunkId & (~(ALL_EXTRA_FLAGS));
 164                         t->extraIsShrinkHeader =
 165                             (pt->t.chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
 166                         t->extraShadows =
 167                             (pt->t.chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
 168                         t->extraObjectType =
 169                             pt->t.objectId >> EXTRA_OBJECT_TYPE_SHIFT;
 170                         t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
 171
 172                         if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) {
 173                                 t->extraEquivalentObjectId = pt->t.byteCount;
 174                         } else {
 175                                 t->extraFileLength = pt->t.byteCount;
 176                         }
 177                 }
 178         }
 179
 180         yaffs_DumpPackedTags2(pt);
 181         yaffs_DumpTags2(t);
 182
 183 }