Fix typos and correct URL.
[yaffs2.git] / 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 }