| 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*/ |
| 364 | |
