[8.09] [kernel] generic-2.6: rename "files" directory to "files-2.6.24" to be consistent
[openwrt/svn-archive/archive.git] / target / linux / generic-2.6 / files-2.6.24 / fs / yaffs2 / yaffs_mtdif1.c
1 /*
2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
3 * yaffs_mtdif1.c NAND mtd interface functions for small-page NAND.
4 *
5 * Copyright (C) 2002 Aleph One Ltd.
6 * for Toby Churchill Ltd and Brightstar Engineering
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 /*
14 * This module provides the interface between yaffs_nand.c and the
15 * MTD API. This version is used when the MTD interface supports the
16 * 'mtd_oob_ops' style calls to read_oob and write_oob, circa 2.6.17,
17 * and we have small-page NAND device.
18 *
19 * These functions are invoked via function pointers in yaffs_nand.c.
20 * This replaces functionality provided by functions in yaffs_mtdif.c
21 * and the yaffs_TagsCompatability functions in yaffs_tagscompat.c that are
22 * called in yaffs_mtdif.c when the function pointers are NULL.
23 * We assume the MTD layer is performing ECC (useNANDECC is true).
24 */
25
26 #include "yportenv.h"
27 #include "yaffs_guts.h"
28 #include "yaffs_packedtags1.h"
29 #include "yaffs_tagscompat.h" // for yaffs_CalcTagsECC
30
31 #include "linux/kernel.h"
32 #include "linux/version.h"
33 #include "linux/types.h"
34 #include "linux/mtd/mtd.h"
35
36 /* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
37 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17))
38
39 const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.3 2007/05/15 20:16:11 ian Exp $";
40
41 #ifndef CONFIG_YAFFS_9BYTE_TAGS
42 # define YTAG1_SIZE 8
43 #else
44 # define YTAG1_SIZE 9
45 #endif
46
47 #if 0
48 /* Use the following nand_ecclayout with MTD when using
49 * CONFIG_YAFFS_9BYTE_TAGS and the older on-NAND tags layout.
50 * If you have existing Yaffs images and the byte order differs from this,
51 * adjust 'oobfree' to match your existing Yaffs data.
52 *
53 * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
54 * pageStatus byte (at NAND spare offset 4) scattered/gathered from/to
55 * the 9th byte.
56 *
57 * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
58 * We have/need PackedTags1 plus pageStatus: T0,T1,T2,T3,T4,T5,T6,T7,P
59 * where Tn are the tag bytes, En are MTD's ECC bytes, P is the pageStatus
60 * byte and B is the small-page bad-block indicator byte.
61 */
62 static struct nand_ecclayout nand_oob_16 = {
63 .eccbytes = 6,
64 .eccpos = { 8, 9, 10, 13, 14, 15 },
65 .oobavail = 9,
66 .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
67 };
68 #endif
69
70 /* Write a chunk (page) of data to NAND.
71 *
72 * Caller always provides ExtendedTags data which are converted to a more
73 * compact (packed) form for storage in NAND. A mini-ECC runs over the
74 * contents of the tags meta-data; used to valid the tags when read.
75 *
76 * - Pack ExtendedTags to PackedTags1 form
77 * - Compute mini-ECC for PackedTags1
78 * - Write data and packed tags to NAND.
79 *
80 * Note: Due to the use of the PackedTags1 meta-data which does not include
81 * a full sequence number (as found in the larger PackedTags2 form) it is
82 * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
83 * discarded and dirty. This is not ideal: newer NAND parts are supposed
84 * to be written just once. When Yaffs performs this operation, this
85 * function is called with a NULL data pointer -- calling MTD write_oob
86 * without data is valid usage (2.6.17).
87 *
88 * Any underlying MTD error results in YAFFS_FAIL.
89 * Returns YAFFS_OK or YAFFS_FAIL.
90 */
91 int nandmtd1_WriteChunkWithTagsToNAND(yaffs_Device *dev,
92 int chunkInNAND, const __u8 * data, const yaffs_ExtendedTags * etags)
93 {
94 struct mtd_info * mtd = dev->genericDevice;
95 int chunkBytes = dev->nDataBytesPerChunk;
96 loff_t addr = ((loff_t)chunkInNAND) * chunkBytes;
97 struct mtd_oob_ops ops;
98 yaffs_PackedTags1 pt1;
99 int retval;
100
101 /* we assume that PackedTags1 and yaffs_Tags are compatible */
102 compile_time_assertion(sizeof(yaffs_PackedTags1) == 12);
103 compile_time_assertion(sizeof(yaffs_Tags) == 8);
104
105 dev->nPageWrites++;
106
107 yaffs_PackTags1(&pt1, etags);
108 yaffs_CalcTagsECC((yaffs_Tags *)&pt1);
109
110 /* When deleting a chunk, the upper layer provides only skeletal
111 * etags, one with chunkDeleted set. However, we need to update the
112 * tags, not erase them completely. So we use the NAND write property
113 * that only zeroed-bits stick and set tag bytes to all-ones and
114 * zero just the (not) deleted bit.
115 */
116 #ifndef CONFIG_YAFFS_9BYTE_TAGS
117 if (etags->chunkDeleted) {
118 memset(&pt1, 0xff, 8);
119 /* clear delete status bit to indicate deleted */
120 pt1.deleted = 0;
121 }
122 #else
123 ((__u8 *)&pt1)[8] = 0xff;
124 if (etags->chunkDeleted) {
125 memset(&pt1, 0xff, 8);
126 /* zero pageStatus byte to indicate deleted */
127 ((__u8 *)&pt1)[8] = 0;
128 }
129 #endif
130
131 memset(&ops, 0, sizeof(ops));
132 ops.mode = MTD_OOB_AUTO;
133 ops.len = (data) ? chunkBytes : 0;
134 ops.ooblen = YTAG1_SIZE;
135 ops.datbuf = (__u8 *)data;
136 ops.oobbuf = (__u8 *)&pt1;
137
138 retval = mtd->write_oob(mtd, addr, &ops);
139 if (retval) {
140 yaffs_trace(YAFFS_TRACE_MTD,
141 "write_oob failed, chunk %d, mtd error %d\n",
142 chunkInNAND, retval);
143 }
144 return retval ? YAFFS_FAIL : YAFFS_OK;
145 }
146
147 /* Return with empty ExtendedTags but add eccResult.
148 */
149 static int rettags(yaffs_ExtendedTags * etags, int eccResult, int retval)
150 {
151 if (etags) {
152 memset(etags, 0, sizeof(*etags));
153 etags->eccResult = eccResult;
154 }
155 return retval;
156 }
157
158 /* Read a chunk (page) from NAND.
159 *
160 * Caller expects ExtendedTags data to be usable even on error; that is,
161 * all members except eccResult and blockBad are zeroed.
162 *
163 * - Check ECC results for data (if applicable)
164 * - Check for blank/erased block (return empty ExtendedTags if blank)
165 * - Check the PackedTags1 mini-ECC (correct if necessary/possible)
166 * - Convert PackedTags1 to ExtendedTags
167 * - Update eccResult and blockBad members to refect state.
168 *
169 * Returns YAFFS_OK or YAFFS_FAIL.
170 */
171 int nandmtd1_ReadChunkWithTagsFromNAND(yaffs_Device *dev,
172 int chunkInNAND, __u8 * data, yaffs_ExtendedTags * etags)
173 {
174 struct mtd_info * mtd = dev->genericDevice;
175 int chunkBytes = dev->nDataBytesPerChunk;
176 loff_t addr = ((loff_t)chunkInNAND) * chunkBytes;
177 int eccres = YAFFS_ECC_RESULT_NO_ERROR;
178 struct mtd_oob_ops ops;
179 yaffs_PackedTags1 pt1;
180 int retval;
181 int deleted;
182
183 dev->nPageReads++;
184
185 memset(&ops, 0, sizeof(ops));
186 ops.mode = MTD_OOB_AUTO;
187 ops.len = (data) ? chunkBytes : 0;
188 ops.ooblen = YTAG1_SIZE;
189 ops.datbuf = data;
190 ops.oobbuf = (__u8 *)&pt1;
191
192 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20))
193 /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
194 * help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
195 */
196 ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
197 #endif
198 /* Read page and oob using MTD.
199 * Check status and determine ECC result.
200 */
201 retval = mtd->read_oob(mtd, addr, &ops);
202 if (retval) {
203 yaffs_trace(YAFFS_TRACE_MTD,
204 "read_oob failed, chunk %d, mtd error %d\n",
205 chunkInNAND, retval);
206 }
207
208 switch (retval) {
209 case 0:
210 /* no error */
211 break;
212
213 case -EUCLEAN:
214 /* MTD's ECC fixed the data */
215 eccres = YAFFS_ECC_RESULT_FIXED;
216 dev->eccFixed++;
217 break;
218
219 case -EBADMSG:
220 /* MTD's ECC could not fix the data */
221 dev->eccUnfixed++;
222 /* fall into... */
223 default:
224 rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
225 etags->blockBad = (mtd->block_isbad)(mtd, addr);
226 return YAFFS_FAIL;
227 }
228
229 /* Check for a blank/erased chunk.
230 */
231 if (yaffs_CheckFF((__u8 *)&pt1, 8)) {
232 /* when blank, upper layers want eccResult to be <= NO_ERROR */
233 return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
234 }
235
236 #ifndef CONFIG_YAFFS_9BYTE_TAGS
237 /* Read deleted status (bit) then return it to it's non-deleted
238 * state before performing tags mini-ECC check. pt1.deleted is
239 * inverted.
240 */
241 deleted = !pt1.deleted;
242 pt1.deleted = 1;
243 #else
244 deleted = (yaffs_CountBits(((__u8 *)&pt1)[8]) < 7);
245 #endif
246
247 /* Check the packed tags mini-ECC and correct if necessary/possible.
248 */
249 retval = yaffs_CheckECCOnTags((yaffs_Tags *)&pt1);
250 switch (retval) {
251 case 0:
252 /* no tags error, use MTD result */
253 break;
254 case 1:
255 /* recovered tags-ECC error */
256 dev->tagsEccFixed++;
257 if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
258 eccres = YAFFS_ECC_RESULT_FIXED;
259 break;
260 default:
261 /* unrecovered tags-ECC error */
262 dev->tagsEccUnfixed++;
263 return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
264 }
265
266 /* Unpack the tags to extended form and set ECC result.
267 * [set shouldBeFF just to keep yaffs_UnpackTags1 happy]
268 */
269 pt1.shouldBeFF = 0xFFFFFFFF;
270 yaffs_UnpackTags1(etags, &pt1);
271 etags->eccResult = eccres;
272
273 /* Set deleted state */
274 etags->chunkDeleted = deleted;
275 return YAFFS_OK;
276 }
277
278 /* Mark a block bad.
279 *
280 * This is a persistant state.
281 * Use of this function should be rare.
282 *
283 * Returns YAFFS_OK or YAFFS_FAIL.
284 */
285 int nandmtd1_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo)
286 {
287 struct mtd_info * mtd = dev->genericDevice;
288 int blocksize = dev->nChunksPerBlock * dev->nDataBytesPerChunk;
289 int retval;
290
291 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad", blockNo);
292
293 retval = mtd->block_markbad(mtd, (loff_t)blocksize * blockNo);
294 return (retval) ? YAFFS_FAIL : YAFFS_OK;
295 }
296
297 /* Check any MTD prerequists.
298 *
299 * Returns YAFFS_OK or YAFFS_FAIL.
300 */
301 static int nandmtd1_TestPrerequists(struct mtd_info * mtd)
302 {
303 /* 2.6.18 has mtd->ecclayout->oobavail */
304 /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
305 int oobavail = mtd->ecclayout->oobavail;
306
307 if (oobavail < YTAG1_SIZE) {
308 yaffs_trace(YAFFS_TRACE_ERROR,
309 "mtd device has only %d bytes for tags, need %d\n",
310 oobavail, YTAG1_SIZE);
311 return YAFFS_FAIL;
312 }
313 return YAFFS_OK;
314 }
315
316 /* Query for the current state of a specific block.
317 *
318 * Examine the tags of the first chunk of the block and return the state:
319 * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
320 * - YAFFS_BLOCK_STATE_NEEDS_SCANNING, the block is in use
321 * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
322 *
323 * Always returns YAFFS_OK.
324 */
325 int nandmtd1_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo,
326 yaffs_BlockState * pState, int *pSequenceNumber)
327 {
328 struct mtd_info * mtd = dev->genericDevice;
329 int chunkNo = blockNo * dev->nChunksPerBlock;
330 yaffs_ExtendedTags etags;
331 int state = YAFFS_BLOCK_STATE_DEAD;
332 int seqnum = 0;
333 int retval;
334
335 /* We don't yet have a good place to test for MTD config prerequists.
336 * Do it here as we are called during the initial scan.
337 */
338 if (nandmtd1_TestPrerequists(mtd) != YAFFS_OK) {
339 return YAFFS_FAIL;
340 }
341
342 retval = nandmtd1_ReadChunkWithTagsFromNAND(dev, chunkNo, NULL, &etags);
343 if (etags.blockBad) {
344 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
345 "block %d is marked bad", blockNo);
346 state = YAFFS_BLOCK_STATE_DEAD;
347 }
348 else if (etags.chunkUsed) {
349 state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
350 seqnum = etags.sequenceNumber;
351 }
352 else {
353 state = YAFFS_BLOCK_STATE_EMPTY;
354 }
355
356 *pState = state;
357 *pSequenceNumber = seqnum;
358
359 /* query always succeeds */
360 return YAFFS_OK;
361 }
362
363 #endif /*KERNEL_VERSION*/