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Diffstat (limited to 'fs/yaffs2/yaffs_mtdif1.c')
| -rw-r--r-- | fs/yaffs2/yaffs_mtdif1.c | 330 |
1 files changed, 330 insertions, 0 deletions
diff --git a/fs/yaffs2/yaffs_mtdif1.c b/fs/yaffs2/yaffs_mtdif1.c new file mode 100644 index 000000000000..51083695eb33 --- /dev/null +++ b/fs/yaffs2/yaffs_mtdif1.c @@ -0,0 +1,330 @@ +/* + * 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 <charles@aleph1.co.uk> + * + * 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_tags compatability 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 (use_nand_ecc is true). + */ + +#include "yportenv.h" +#include "yaffs_trace.h" +#include "yaffs_guts.h" +#include "yaffs_packedtags1.h" +#include "yaffs_tagscompat.h" /* for yaffs_calc_tags_ecc */ +#include "yaffs_linux.h" + +#include "linux/kernel.h" +#include "linux/version.h" +#include "linux/types.h" +#include "linux/mtd/mtd.h" + +#ifndef CONFIG_YAFFS_9BYTE_TAGS +# define YTAG1_SIZE 8 +#else +# define YTAG1_SIZE 9 +#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 packed_tags1 form + * - Compute mini-ECC for packed_tags1 + * - Write data and packed tags to NAND. + * + * Note: Due to the use of the packed_tags1 meta-data which does not include + * a full sequence number (as found in the larger packed_tags2 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_write_chunk_tags(struct yaffs_dev *dev, + int nand_chunk, const u8 * data, + const struct yaffs_ext_tags *etags) +{ + struct mtd_info *mtd = yaffs_dev_to_mtd(dev); + int chunk_bytes = dev->data_bytes_per_chunk; + loff_t addr = ((loff_t) nand_chunk) * chunk_bytes; + struct mtd_oob_ops ops; + struct yaffs_packed_tags1 pt1; + int retval; + + /* we assume that packed_tags1 and struct yaffs_tags are compatible */ + compile_time_assertion(sizeof(struct yaffs_packed_tags1) == 12); + compile_time_assertion(sizeof(struct yaffs_tags) == 8); + + yaffs_pack_tags1(&pt1, etags); + yaffs_calc_tags_ecc((struct yaffs_tags *)&pt1); + + /* When deleting a chunk, the upper layer provides only skeletal + * etags, one with is_deleted 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->is_deleted) { + memset(&pt1, 0xff, 8); + /* clear delete status bit to indicate deleted */ + pt1.deleted = 0; + } +#else + ((u8 *) & pt1)[8] = 0xff; + if (etags->is_deleted) { + memset(&pt1, 0xff, 8); + /* zero page_status byte to indicate deleted */ + ((u8 *) & pt1)[8] = 0; + } +#endif + + memset(&ops, 0, sizeof(ops)); + ops.mode = MTD_OOB_AUTO; + ops.len = (data) ? chunk_bytes : 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", + nand_chunk, retval); + } + return retval ? YAFFS_FAIL : YAFFS_OK; +} + +/* Return with empty ExtendedTags but add ecc_result. + */ +static int rettags(struct yaffs_ext_tags *etags, int ecc_result, int retval) +{ + if (etags) { + memset(etags, 0, sizeof(*etags)); + etags->ecc_result = ecc_result; + } + return retval; +} + +/* Read a chunk (page) from NAND. + * + * Caller expects ExtendedTags data to be usable even on error; that is, + * all members except ecc_result and block_bad are zeroed. + * + * - Check ECC results for data (if applicable) + * - Check for blank/erased block (return empty ExtendedTags if blank) + * - Check the packed_tags1 mini-ECC (correct if necessary/possible) + * - Convert packed_tags1 to ExtendedTags + * - Update ecc_result and block_bad members to refect state. + * + * Returns YAFFS_OK or YAFFS_FAIL. + */ +int nandmtd1_read_chunk_tags(struct yaffs_dev *dev, + int nand_chunk, u8 * data, + struct yaffs_ext_tags *etags) +{ + struct mtd_info *mtd = yaffs_dev_to_mtd(dev); + int chunk_bytes = dev->data_bytes_per_chunk; + loff_t addr = ((loff_t) nand_chunk) * chunk_bytes; + int eccres = YAFFS_ECC_RESULT_NO_ERROR; + struct mtd_oob_ops ops; + struct yaffs_packed_tags1 pt1; + int retval; + int deleted; + + memset(&ops, 0, sizeof(ops)); + ops.mode = MTD_OOB_AUTO; + ops.len = (data) ? chunk_bytes : 0; + ops.ooblen = YTAG1_SIZE; + ops.datbuf = data; + ops.oobbuf = (u8 *) & pt1; + + /* 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", + nand_chunk, retval); + } + + switch (retval) { + case 0: + /* no error */ + break; + + case -EUCLEAN: + /* MTD's ECC fixed the data */ + eccres = YAFFS_ECC_RESULT_FIXED; + dev->n_ecc_fixed++; + break; + + case -EBADMSG: + /* MTD's ECC could not fix the data */ + dev->n_ecc_unfixed++; + /* fall into... */ + default: + rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0); + etags->block_bad = (mtd->block_isbad) (mtd, addr); + return YAFFS_FAIL; + } + + /* Check for a blank/erased chunk. + */ + if (yaffs_check_ff((u8 *) & pt1, 8)) { + /* when blank, upper layers want ecc_result 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_count_bits(((u8 *) & pt1)[8]) < 7); +#endif + + /* Check the packed tags mini-ECC and correct if necessary/possible. + */ + retval = yaffs_check_tags_ecc((struct yaffs_tags *)&pt1); + switch (retval) { + case 0: + /* no tags error, use MTD result */ + break; + case 1: + /* recovered tags-ECC error */ + dev->n_tags_ecc_fixed++; + if (eccres == YAFFS_ECC_RESULT_NO_ERROR) + eccres = YAFFS_ECC_RESULT_FIXED; + break; + default: + /* unrecovered tags-ECC error */ + dev->n_tags_ecc_unfixed++; + return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL); + } + + /* Unpack the tags to extended form and set ECC result. + * [set should_be_ff just to keep yaffs_unpack_tags1 happy] + */ + pt1.should_be_ff = 0xFFFFFFFF; + yaffs_unpack_tags1(etags, &pt1); + etags->ecc_result = eccres; + + /* Set deleted state */ + etags->is_deleted = 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_mark_block_bad(struct yaffs_dev *dev, int block_no) +{ + struct mtd_info *mtd = yaffs_dev_to_mtd(dev); + int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk; + int retval; + + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, + "marking block %d bad", block_no); + + retval = mtd->block_markbad(mtd, (loff_t) blocksize * block_no); + return (retval) ? YAFFS_FAIL : YAFFS_OK; +} + +/* Check any MTD prerequists. + * + * Returns YAFFS_OK or YAFFS_FAIL. + */ +static int nandmtd1_test_prerequists(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", + 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_query_block(struct yaffs_dev *dev, int block_no, + enum yaffs_block_state *state_ptr, u32 * seq_ptr) +{ + struct mtd_info *mtd = yaffs_dev_to_mtd(dev); + int chunk_num = block_no * dev->param.chunks_per_block; + loff_t addr = (loff_t) chunk_num * dev->data_bytes_per_chunk; + struct yaffs_ext_tags 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_test_prerequists(mtd) != YAFFS_OK) + return YAFFS_FAIL; + + retval = nandmtd1_read_chunk_tags(dev, chunk_num, NULL, &etags); + etags.block_bad = (mtd->block_isbad) (mtd, addr); + if (etags.block_bad) { + yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, + "block %d is marked bad", block_no); + state = YAFFS_BLOCK_STATE_DEAD; + } else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) { + /* bad tags, need to look more closely */ + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING; + } else if (etags.chunk_used) { + state = YAFFS_BLOCK_STATE_NEEDS_SCANNING; + seqnum = etags.seq_number; + } else { + state = YAFFS_BLOCK_STATE_EMPTY; + } + + *state_ptr = state; + *seq_ptr = seqnum; + + /* query always succeeds */ + return YAFFS_OK; +} |