2 * YAFFS: Yet another FFS. A NAND-flash specific file system.
3 * yaffs_mtdif1.c NAND mtd interface functions for small-page NAND.
5 * Copyright (C) 2002 Aleph One Ltd.
6 * for Toby Churchill Ltd and Brightstar Engineering
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.
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.
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).
27 #include "yaffs_trace.h"
28 #include "yaffs_guts.h"
29 #include "yaffs_packedtags1.h"
30 #include "yaffs_tagscompat.h" /* for yaffs_CalcTagsECC */
31 #include "yaffs_linux.h"
33 #include "linux/kernel.h"
34 #include "linux/version.h"
35 #include "linux/types.h"
36 #include "linux/mtd/mtd.h"
38 /* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
39 #if (MTD_VERSION_CODE > MTD_VERSION(2, 6, 17))
41 const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.13 2010-02-18 01:18:04 charles Exp $";
43 #ifndef CONFIG_YAFFS_9BYTE_TAGS
50 /* Use the following nand_ecclayout with MTD when using
51 * CONFIG_YAFFS_9BYTE_TAGS and the older on-NAND tags layout.
52 * If you have existing Yaffs images and the byte order differs from this,
53 * adjust 'oobfree' to match your existing Yaffs data.
55 * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
56 * pageStatus byte (at NAND spare offset 4) scattered/gathered from/to
59 * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
60 * We have/need PackedTags1 plus pageStatus: T0,T1,T2,T3,T4,T5,T6,T7,P
61 * where Tn are the tag bytes, En are MTD's ECC bytes, P is the pageStatus
62 * byte and B is the small-page bad-block indicator byte.
64 static struct nand_ecclayout nand_oob_16 = {
66 .eccpos = { 8, 9, 10, 13, 14, 15 },
68 .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
72 /* Write a chunk (page) of data to NAND.
74 * Caller always provides ExtendedTags data which are converted to a more
75 * compact (packed) form for storage in NAND. A mini-ECC runs over the
76 * contents of the tags meta-data; used to valid the tags when read.
78 * - Pack ExtendedTags to PackedTags1 form
79 * - Compute mini-ECC for PackedTags1
80 * - Write data and packed tags to NAND.
82 * Note: Due to the use of the PackedTags1 meta-data which does not include
83 * a full sequence number (as found in the larger PackedTags2 form) it is
84 * necessary for Yaffs to re-write a chunk/page (just once) to mark it as
85 * discarded and dirty. This is not ideal: newer NAND parts are supposed
86 * to be written just once. When Yaffs performs this operation, this
87 * function is called with a NULL data pointer -- calling MTD write_oob
88 * without data is valid usage (2.6.17).
90 * Any underlying MTD error results in YAFFS_FAIL.
91 * Returns YAFFS_OK or YAFFS_FAIL.
93 int nandmtd1_WriteChunkWithTagsToNAND(yaffs_Device *dev,
94 int chunkInNAND, const __u8 *data, const yaffs_ExtendedTags *etags)
96 struct mtd_info *mtd = yaffs_DeviceToContext(dev)->mtd;
97 int chunkBytes = dev->nDataBytesPerChunk;
98 loff_t addr = ((loff_t)chunkInNAND) * chunkBytes;
99 struct mtd_oob_ops ops;
100 yaffs_PackedTags1 pt1;
103 /* we assume that PackedTags1 and yaffs_Tags are compatible */
104 compile_time_assertion(sizeof(yaffs_PackedTags1) == 12);
105 compile_time_assertion(sizeof(yaffs_Tags) == 8);
107 yaffs_PackTags1(&pt1, etags);
108 yaffs_CalcTagsECC((yaffs_Tags *)&pt1);
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.
116 #ifndef CONFIG_YAFFS_9BYTE_TAGS
117 if (etags->chunkDeleted) {
118 memset(&pt1, 0xff, 8);
119 /* clear delete status bit to indicate deleted */
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;
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;
138 retval = mtd->write_oob(mtd, addr, &ops);
140 yaffs_trace(YAFFS_TRACE_MTD,
141 "write_oob failed, chunk %d, mtd error %d\n",
142 chunkInNAND, retval);
144 return retval ? YAFFS_FAIL : YAFFS_OK;
147 /* Return with empty ExtendedTags but add eccResult.
149 static int rettags(yaffs_ExtendedTags *etags, int eccResult, int retval)
152 memset(etags, 0, sizeof(*etags));
153 etags->eccResult = eccResult;
158 /* Read a chunk (page) from NAND.
160 * Caller expects ExtendedTags data to be usable even on error; that is,
161 * all members except eccResult and blockBad are zeroed.
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.
169 * Returns YAFFS_OK or YAFFS_FAIL.
171 int nandmtd1_ReadChunkWithTagsFromNAND(yaffs_Device *dev,
172 int chunkInNAND, __u8 *data, yaffs_ExtendedTags *etags)
174 struct mtd_info *mtd = yaffs_DeviceToContext(dev)->mtd;
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;
183 memset(&ops, 0, sizeof(ops));
184 ops.mode = MTD_OOB_AUTO;
185 ops.len = (data) ? chunkBytes : 0;
186 ops.ooblen = YTAG1_SIZE;
188 ops.oobbuf = (__u8 *)&pt1;
190 #if (MTD_VERSION_CODE < MTD_VERSION(2, 6, 20))
191 /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
192 * help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
194 ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
196 /* Read page and oob using MTD.
197 * Check status and determine ECC result.
199 retval = mtd->read_oob(mtd, addr, &ops);
201 yaffs_trace(YAFFS_TRACE_MTD,
202 "read_oob failed, chunk %d, mtd error %d\n",
203 chunkInNAND, retval);
212 /* MTD's ECC fixed the data */
213 eccres = YAFFS_ECC_RESULT_FIXED;
218 /* MTD's ECC could not fix the data */
222 rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
223 etags->blockBad = (mtd->block_isbad)(mtd, addr);
227 /* Check for a blank/erased chunk.
229 if (yaffs_CheckFF((__u8 *)&pt1, 8)) {
230 /* when blank, upper layers want eccResult to be <= NO_ERROR */
231 return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
234 #ifndef CONFIG_YAFFS_9BYTE_TAGS
235 /* Read deleted status (bit) then return it to it's non-deleted
236 * state before performing tags mini-ECC check. pt1.deleted is
239 deleted = !pt1.deleted;
242 deleted = (yaffs_CountBits(((__u8 *)&pt1)[8]) < 7);
245 /* Check the packed tags mini-ECC and correct if necessary/possible.
247 retval = yaffs_CheckECCOnTags((yaffs_Tags *)&pt1);
250 /* no tags error, use MTD result */
253 /* recovered tags-ECC error */
255 if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
256 eccres = YAFFS_ECC_RESULT_FIXED;
259 /* unrecovered tags-ECC error */
260 dev->tagsEccUnfixed++;
261 return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
264 /* Unpack the tags to extended form and set ECC result.
265 * [set shouldBeFF just to keep yaffs_UnpackTags1 happy]
267 pt1.shouldBeFF = 0xFFFFFFFF;
268 yaffs_UnpackTags1(etags, &pt1);
269 etags->eccResult = eccres;
271 /* Set deleted state */
272 etags->chunkDeleted = deleted;
278 * This is a persistant state.
279 * Use of this function should be rare.
281 * Returns YAFFS_OK or YAFFS_FAIL.
283 int nandmtd1_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo)
285 struct mtd_info *mtd = yaffs_DeviceToContext(dev)->mtd;
286 int blocksize = dev->param.nChunksPerBlock * dev->nDataBytesPerChunk;
289 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad\n", blockNo);
291 retval = mtd->block_markbad(mtd, (loff_t)blocksize * blockNo);
292 return (retval) ? YAFFS_FAIL : YAFFS_OK;
295 /* Check any MTD prerequists.
297 * Returns YAFFS_OK or YAFFS_FAIL.
299 static int nandmtd1_TestPrerequists(struct mtd_info *mtd)
301 /* 2.6.18 has mtd->ecclayout->oobavail */
302 /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
303 int oobavail = mtd->ecclayout->oobavail;
305 if (oobavail < YTAG1_SIZE) {
306 yaffs_trace(YAFFS_TRACE_ERROR,
307 "mtd device has only %d bytes for tags, need %d\n",
308 oobavail, YTAG1_SIZE);
314 /* Query for the current state of a specific block.
316 * Examine the tags of the first chunk of the block and return the state:
317 * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
318 * - YAFFS_BLOCK_STATE_NEEDS_SCANNING, the block is in use
319 * - YAFFS_BLOCK_STATE_EMPTY, the block is clean
321 * Always returns YAFFS_OK.
323 int nandmtd1_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo,
324 yaffs_BlockState *pState, __u32 *pSequenceNumber)
326 struct mtd_info *mtd = yaffs_DeviceToContext(dev)->mtd;
327 int chunkNo = blockNo * dev->param.nChunksPerBlock;
328 loff_t addr = (loff_t)chunkNo * dev->nDataBytesPerChunk;
329 yaffs_ExtendedTags etags;
330 int state = YAFFS_BLOCK_STATE_DEAD;
334 /* We don't yet have a good place to test for MTD config prerequists.
335 * Do it here as we are called during the initial scan.
337 if (nandmtd1_TestPrerequists(mtd) != YAFFS_OK)
340 retval = nandmtd1_ReadChunkWithTagsFromNAND(dev, chunkNo, NULL, &etags);
341 etags.blockBad = (mtd->block_isbad)(mtd, addr);
342 if (etags.blockBad) {
343 yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,
344 "block %d is marked bad\n", blockNo);
345 state = YAFFS_BLOCK_STATE_DEAD;
346 } else if (etags.eccResult != YAFFS_ECC_RESULT_NO_ERROR) {
347 /* bad tags, need to look more closely */
348 state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
349 } else if (etags.chunkUsed) {
350 state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
351 seqnum = etags.sequenceNumber;
353 state = YAFFS_BLOCK_STATE_EMPTY;
357 *pSequenceNumber = seqnum;
359 /* query always succeeds */
363 #endif /*MTD_VERSION*/