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Diffstat (limited to 'fs/yaffs2/yaffs_mtdif1.c')
| -rw-r--r-- | fs/yaffs2/yaffs_mtdif1.c | 369 |
1 files changed, 369 insertions, 0 deletions
diff --git a/fs/yaffs2/yaffs_mtdif1.c b/fs/yaffs2/yaffs_mtdif1.c new file mode 100644 index 0000000..36185b6 --- /dev/null +++ b/fs/yaffs2/yaffs_mtdif1.c @@ -0,0 +1,369 @@ +/* + * YAFFS: Yet another FFS. A NAND-flash specific file system. + * yaffs_mtdif1.c NAND mtd interface functions for small-page NAND. + * + * Copyright (C) 2002 Aleph One Ltd. + * for Toby Churchill Ltd and Brightstar Engineering + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +/* + * This module provides the interface between yaffs_nand.c and the + * MTD API. This version is used when the MTD interface supports the + * 'mtd_oob_ops' style calls to read_oob and write_oob, circa 2.6.17, + * and we have small-page NAND device. + * + * These functions are invoked via function pointers in yaffs_nand.c. + * This replaces functionality provided by functions in yaffs_mtdif.c + * and the yaffs_TagsCompatability functions in yaffs_tagscompat.c that are + * called in yaffs_mtdif.c when the function pointers are NULL. + * We assume the MTD layer is performing ECC (useNANDECC is true). + */ + +#include "yportenv.h" +#include "yaffs_guts.h" +#include "yaffs_packedtags1.h" +#include "yaffs_tagscompat.h" // for yaffs_CalcTagsECC + +#include "linux/kernel.h" +#include "linux/version.h" +#include "linux/types.h" +#include "linux/mtd/mtd.h" + +/* Don't compile this module if we don't have MTD's mtd_oob_ops interface */ +#if (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17)) + +const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.5 2007/10/29 14:59:57 imcd Exp $"; + +#ifndef CONFIG_YAFFS_9BYTE_TAGS +# define YTAG1_SIZE 8 +#else +# define YTAG1_SIZE 9 +#endif + +#if 0 +/* Use the following nand_ecclayout with MTD when using + * CONFIG_YAFFS_9BYTE_TAGS and the older on-NAND tags layout. + * If you have existing Yaffs images and the byte order differs from this, + * adjust 'oobfree' to match your existing Yaffs data. + * + * This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the + * pageStatus byte (at NAND spare offset 4) scattered/gathered from/to + * the 9th byte. + * + * Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5 + * We have/need PackedTags1 plus pageStatus: T0,T1,T2,T3,T4,T5,T6,T7,P + * where Tn are the tag bytes, En are MTD's ECC bytes, P is the pageStatus + * byte and B is the small-page bad-block indicator byte. + */ +static struct nand_ecclayout nand_oob_16 = { + .eccbytes = 6, + .eccpos = { 8, 9, 10, 13, 14, 15 }, + .oobavail = 9, + .oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } } +}; +#endif + +/* Write a chunk (page) of data to NAND. + * + * Caller always provides ExtendedTags data which are converted to a more + * compact (packed) form for storage in NAND. A mini-ECC runs over the + * contents of the tags meta-data; used to valid the tags when read. + * + * - Pack ExtendedTags to PackedTags1 form + * - Compute mini-ECC for PackedTags1 + * - Write data and packed tags to NAND. + * + * Note: Due to the use of the PackedTags1 meta-data which does not include + * a full sequence number (as found in the larger PackedTags2 form) it is + * necessary for Yaffs to re-write a chunk/page (just once) to mark it as + * discarded and dirty. This is not ideal: newer NAND parts are supposed + * to be written just once. When Yaffs performs this operation, this + * function is called with a NULL data pointer -- calling MTD write_oob + * without data is valid usage (2.6.17). + * + * Any underlying MTD error results in YAFFS_FAIL. + * Returns YAFFS_OK or YAFFS_FAIL. + */ +int nandmtd1_WriteChunkWithTagsToNAND(yaffs_Device *dev, + int chunkInNAND, const __u8 * data, const yaffs_ExtendedTags * etags) +{ + struct mtd_info * mtd = dev->genericDevice; + int chunkBytes = dev->nDataBytesPerChunk; + loff_t addr = ((loff_t)chunkInNAND) * chunkBytes; + struct mtd_oob_ops ops; + yaffs_PackedTags1 pt1; + int retval; + + /* we assume that PackedTags1 and yaffs_Tags are compatible */ + compile_time_assertion(sizeof(yaffs_PackedTags1) == 12); + compile_time_assertion(sizeof(yaffs_Tags) == 8); + + dev->nPageWrites++; + + yaffs_PackTags1(&pt1, etags); + yaffs_CalcTagsECC((yaffs_Tags *)&pt1); + + /* When deleting a chunk, the upper layer provides only skeletal + * etags, one with chunkDeleted set. However, we need to update the + * tags, not erase them completely. So we use the NAND write property + * that only zeroed-bits stick and set tag bytes to all-ones and + * zero just the (not) deleted bit. + */ +#ifndef CONFIG_YAFFS_9BYTE_TAGS + if (etags->chunkDeleted) { + memset(&pt1, 0xff, 8); + /* clear delete status bit to indicate deleted */ + pt1.deleted = 0; + } +#else + ((__u8 *)&pt1)[8] = 0xff; + if (etags->chunkDeleted) { + memset(&pt1, 0xff, 8); + /* zero pageStatus byte to indicate deleted */ + ((__u8 *)&pt1)[8] = 0; + } +#endif + + memset(&ops, 0, sizeof(ops)); + ops.mode = MTD_OOB_AUTO; + ops.len = (data) ? chunkBytes : 0; + ops.ooblen = YTAG1_SIZE; + ops.datbuf = (__u8 *)data; + ops.oobbuf = (__u8 *)&pt1; + + retval = mtd->write_oob(mtd, addr, &ops); + if (retval) { + yaffs_trace(YAFFS_TRACE_MTD, + "write_oob failed, chunk %d, mtd error %d\n", + chunkInNAND, retval); + } + return retval ? YAFFS_FAIL : YAFFS_OK; +} + +/* Return with empty ExtendedTags but add eccResult. + */ +static int rettags(yaffs_ExtendedTags * etags, int eccResult, int retval) +{ + if (etags) { + memset(etags, 0, sizeof(*etags)); + etags->eccResult = eccResult; + } + return retval; +} + +/* Read a chunk (page) from NAND. + * + * Caller expects ExtendedTags data to be usable even on error; that is, + * all members except eccResult and blockBad are zeroed. + * + * - Check ECC results for data (if applicable) + * - Check for blank/erased block (return empty ExtendedTags if blank) + * - Check the PackedTags1 mini-ECC (correct if necessary/possible) + * - Convert PackedTags1 to ExtendedTags + * - Update eccResult and blockBad members to refect state. + * + * Returns YAFFS_OK or YAFFS_FAIL. + */ +int nandmtd1_ReadChunkWithTagsFromNAND(yaffs_Device *dev, + int chunkInNAND, __u8 * data, yaffs_ExtendedTags * etags) +{ + struct mtd_info * mtd = dev->genericDevice; + int chunkBytes = dev->nDataBytesPerChunk; + loff_t addr = ((loff_t)chunkInNAND) * chunkBytes; + int eccres = YAFFS_ECC_RESULT_NO_ERROR; + struct mtd_oob_ops ops; + yaffs_PackedTags1 pt1; + int retval; + int deleted; + + dev->nPageReads++; + + memset(&ops, 0, sizeof(ops)); + ops.mode = MTD_OOB_AUTO; + ops.len = (data) ? chunkBytes : 0; + ops.ooblen = YTAG1_SIZE; + ops.datbuf = data; + ops.oobbuf = (__u8 *)&pt1; + +#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,20)) + /* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug; + * help it out with ops.len = ops.ooblen when ops.datbuf == NULL. + */ + ops.len = (ops.datbuf) ? ops.len : ops.ooblen; +#endif + /* Read page and oob using MTD. + * Check status and determine ECC result. + */ + retval = mtd->read_oob(mtd, addr, &ops); + if (retval) { + yaffs_trace(YAFFS_TRACE_MTD, + "read_oob failed, chunk %d, mtd error %d\n", + chunkInNAND, retval); + } + + switch (retval) { + case 0: + /* no error */ + break; + + case -EUCLEAN: + /* MTD's ECC fixed the data */ + eccres = YAFFS_ECC_RESULT_FIXED; + dev->eccFixed++; + break; + + case -EBADMSG: + /* MTD's ECC could not fix the data */ + dev->eccUnfixed++; + /* fall into... */ + default: + rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0); + etags->blockBad = (mtd->block_isbad)(mtd, addr); + return YAFFS_FAIL; + } + + /* Check for a blank/erased chunk. + */ + if (yaffs_CheckFF((__u8 *)&pt1, 8)) { + /* when blank, upper layers want eccResult to be <= NO_ERROR */ + return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK); + } + +#ifndef CONFIG_YAFFS_9BYTE_TAGS + /* Read deleted status (bit) then return it to it's non-deleted + * state before performing tags mini-ECC check. pt1.deleted is + * inverted. + */ + deleted = !pt1.deleted; + pt1.deleted = 1; +#else + deleted = (yaffs_CountBits(((__u8 *)&pt1)[8]) < 7); +#endif + + /* Check the packed tags mini-ECC and correct if necessary/possible. + */ + retval = yaffs_CheckECCOnTags((yaffs_Tags *)&pt1); + switch (retval) { + case 0: + /* no tags error, use MTD result */ + break; + case 1: + /* recovered tags-ECC error */ + dev->tagsEccFixed++; + if (eccres == YAFFS_ECC_RESULT_NO_ERROR) + eccres = YAFFS_ECC_RESULT_FIXED; + break; + default: + /* unrecovered tags-ECC error */ + dev->tagsEccUnfixed++; + return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL); + } + + /* Unpack the tags to extended form and set ECC result. + * [set shouldBeFF just to keep yaffs_UnpackTags1 happy] + */ + pt1.shouldBeFF = 0xFFFFFFFF; + yaffs_UnpackTags1(etags, &pt1); + etags->eccResult = eccres; + + /* Set deleted state */ + etags->chunkDeleted = deleted; + return YAFFS_OK; +} + +/* Mark a block bad. + * + * This is a persistant state. + * Use of this function should be rare. + * + * Returns YAFFS_OK or YAFFS_FAIL. + */ +int nandmtd1_MarkNANDBlockBad(struct yaffs_DeviceStruct *dev, int blockNo) +{ + struct mtd_info * mtd = dev->genericDevice; + int blocksize = dev->nChunksPerBlock * dev->nDataBytesPerChunk; + int retval; + + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad\n", blockNo); + + retval = mtd->block_markbad(mtd, (loff_t)blocksize * blockNo); + return (retval) ? YAFFS_FAIL : YAFFS_OK; +} + +/* Check any MTD prerequists. + * + * Returns YAFFS_OK or YAFFS_FAIL. + */ +static int nandmtd1_TestPrerequists(struct mtd_info * mtd) +{ + /* 2.6.18 has mtd->ecclayout->oobavail */ + /* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */ + int oobavail = mtd->ecclayout->oobavail; + + if (oobavail < YTAG1_SIZE) { + yaffs_trace(YAFFS_TRACE_ERROR, + "mtd device has only %d bytes for tags, need %d\n", + oobavail, YTAG1_SIZE); + return YAFFS_FAIL; + } + return YAFFS_OK; +} + +/* Query for the current state of a specific block. + * + * Examine the tags of the first chunk of the block and return the state: + * - YAFFS_BLOCK_STATE_DEAD, the block is marked bad + * - YAFFS_BLOCK_STATE_NEEDS_SCANNING, the block is in use + * - YAFFS_BLOCK_STATE_EMPTY, the block is clean + * + * Always returns YAFFS_OK. + */ +int nandmtd1_QueryNANDBlock(struct yaffs_DeviceStruct *dev, int blockNo, + yaffs_BlockState * pState, int *pSequenceNumber) +{ + struct mtd_info * mtd = dev->genericDevice; + int chunkNo = blockNo * dev->nChunksPerBlock; + loff_t addr = (loff_t)chunkNo * dev->nDataBytesPerChunk; + yaffs_ExtendedTags etags; + int state = YAFFS_BLOCK_STATE_DEAD; + int seqnum = 0; + int retval; + + /* We don't yet have a good place to test for MTD config prerequists. + * Do it here as we are called during the initial scan. + */ + if (nandmtd1_TestPrerequists(mtd) != YAFFS_OK) { + return YAFFS_FAIL; + } + + retval = nandmtd1_ReadChunkWithTagsFromNAND(dev, chunkNo, NULL, &etags); + etags.blockBad = (mtd->block_isbad)(mtd, addr); + if (etags.blockBad) { + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, + "block %d is marked bad\n", blockNo); + state = YAFFS_BLOCK_STATE_DEAD; + } + else if (etags.eccResult != YAFFS_ECC_RESULT_NO_ERROR) { + /* bad tags, need to look more closely */ + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING; + } + else if (etags.chunkUsed) { + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING; + seqnum = etags.sequenceNumber; + } + else { + state = YAFFS_BLOCK_STATE_EMPTY; + } + + *pState = state; + *pSequenceNumber = seqnum; + + /* query always succeeds */ + return YAFFS_OK; +} + +#endif /*KERNEL_VERSION*/ |