/* * YAFFS: Yet another FFS. A NAND-flash specific file system. * * Copyright (C) 2002-2010 Aleph One Ltd. * for Toby Churchill Ltd and Brightstar Engineering * * Created by Charles Manning * * 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_trace.h" #include "yaffs_guts.h" #include "yaffs_packedtags1.h" #include "yaffs_tagscompat.h" /* for yaffs_CalcTagsECC */ #include "yaffs_linux.h" #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 (MTD_VERSION_CODE > MTD_VERSION(2, 6, 17)) #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 = yaffs_DeviceToMtd(dev); 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); 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) { T(YAFFS_TRACE_MTD, (TSTR("write_oob failed, chunk %d, mtd error %d"TENDSTR), 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 = yaffs_DeviceToMtd(dev); 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; 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 (MTD_VERSION_CODE < MTD_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) { T(YAFFS_TRACE_MTD, (TSTR("read_oob failed, chunk %d, mtd error %d"TENDSTR), 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 = yaffs_DeviceToMtd(dev); int blocksize = dev->param.nChunksPerBlock * dev->nDataBytesPerChunk; int retval; T(YAFFS_TRACE_BAD_BLOCKS,(TSTR("marking block %d bad"TENDSTR), 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) { T(YAFFS_TRACE_ERROR, (TSTR("mtd device has only %d bytes for tags, need %d"TENDSTR), 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, __u32 *pSequenceNumber) { struct mtd_info *mtd = yaffs_DeviceToMtd(dev); int chunkNo = blockNo * dev->param.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) { T(YAFFS_TRACE_BAD_BLOCKS, (TSTR("block %d is marked bad"TENDSTR), 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 /*MTD_VERSION*/