362 lines
11 KiB
C
362 lines
11 KiB
C
/*
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* YAFFS: Yet another FFS. A NAND-flash specific file system.
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* yaffs_mtdif1.c NAND mtd interface functions for small-page NAND.
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*
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* Copyright (C) 2002-2010 Aleph One Ltd.
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* for Toby Churchill Ltd and Brightstar Engineering
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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/*
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* This module provides the interface between yaffs_nand.c and the
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* MTD API. This version is used when the MTD interface supports the
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* 'mtd_oob_ops' style calls to read_oob and write_oob, circa 2.6.17,
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* and we have small-page NAND device.
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*
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* These functions are invoked via function pointers in yaffs_nand.c.
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* This replaces functionality provided by functions in yaffs_mtdif.c
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* and the yaffs_tags_tCompatability functions in yaffs_tagscompat.c that are
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* called in yaffs_mtdif.c when the function pointers are NULL.
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* We assume the MTD layer is performing ECC (use_nand_ecc is true).
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*/
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#include "yportenv.h"
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#include "yaffs_trace.h"
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#include "yaffs_guts.h"
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#include "yaffs_packedtags1.h"
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#include "yaffs_tagscompat.h" /* for yaffs_calc_tags_ecc */
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#include "yaffs_linux.h"
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#include "linux/kernel.h"
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#include "linux/version.h"
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#include "linux/types.h"
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#include "linux/mtd/mtd.h"
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/* Don't compile this module if we don't have MTD's mtd_oob_ops interface */
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#if (MTD_VERSION_CODE > MTD_VERSION(2, 6, 17))
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#ifndef CONFIG_YAFFS_9BYTE_TAGS
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# define YTAG1_SIZE 8
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#else
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# define YTAG1_SIZE 9
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#endif
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#if 0
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/* Use the following nand_ecclayout with MTD when using
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* CONFIG_YAFFS_9BYTE_TAGS and the older on-NAND tags layout.
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* If you have existing Yaffs images and the byte order differs from this,
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* adjust 'oobfree' to match your existing Yaffs data.
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*
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* This nand_ecclayout scatters/gathers to/from the old-yaffs layout with the
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* page_status byte (at NAND spare offset 4) scattered/gathered from/to
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* the 9th byte.
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*
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* Old-style on-NAND format: T0,T1,T2,T3,P,B,T4,T5,E0,E1,E2,T6,T7,E3,E4,E5
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* We have/need PackedTags1 plus page_status: T0,T1,T2,T3,T4,T5,T6,T7,P
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* where Tn are the tag bytes, En are MTD's ECC bytes, P is the page_status
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* byte and B is the small-page bad-block indicator byte.
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*/
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static struct nand_ecclayout nand_oob_16 = {
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.eccbytes = 6,
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.eccpos = { 8, 9, 10, 13, 14, 15 },
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.oobavail = 9,
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.oobfree = { { 0, 4 }, { 6, 2 }, { 11, 2 }, { 4, 1 } }
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};
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#endif
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/* Write a chunk (page) of data to NAND.
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*
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* Caller always provides ExtendedTags data which are converted to a more
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* compact (packed) form for storage in NAND. A mini-ECC runs over the
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* contents of the tags meta-data; used to valid the tags when read.
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*
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* - Pack ExtendedTags to PackedTags1 form
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* - Compute mini-ECC for PackedTags1
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* - Write data and packed tags to NAND.
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*
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* Note: Due to the use of the PackedTags1 meta-data which does not include
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* a full sequence number (as found in the larger PackedTags2 form) it is
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* necessary for Yaffs to re-write a chunk/page (just once) to mark it as
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* discarded and dirty. This is not ideal: newer NAND parts are supposed
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* to be written just once. When Yaffs performs this operation, this
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* function is called with a NULL data pointer -- calling MTD write_oob
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* without data is valid usage (2.6.17).
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*
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* Any underlying MTD error results in YAFFS_FAIL.
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* Returns YAFFS_OK or YAFFS_FAIL.
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*/
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int nandmtd1_WriteChunkWithTagsToNAND(yaffs_dev_t *dev,
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int nand_chunk, const __u8 *data, const yaffs_ext_tags *etags)
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{
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struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
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int chunkBytes = dev->data_bytes_per_chunk;
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loff_t addr = ((loff_t)nand_chunk) * chunkBytes;
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struct mtd_oob_ops ops;
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yaffs_PackedTags1 pt1;
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int retval;
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/* we assume that PackedTags1 and yaffs_tags_t are compatible */
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compile_time_assertion(sizeof(yaffs_PackedTags1) == 12);
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compile_time_assertion(sizeof(yaffs_tags_t) == 8);
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yaffs_PackTags1(&pt1, etags);
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yaffs_calc_tags_ecc((yaffs_tags_t *)&pt1);
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/* When deleting a chunk, the upper layer provides only skeletal
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* etags, one with is_deleted set. However, we need to update the
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* tags, not erase them completely. So we use the NAND write property
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* that only zeroed-bits stick and set tag bytes to all-ones and
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* zero just the (not) deleted bit.
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*/
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#ifndef CONFIG_YAFFS_9BYTE_TAGS
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if (etags->is_deleted) {
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memset(&pt1, 0xff, 8);
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/* clear delete status bit to indicate deleted */
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pt1.deleted = 0;
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}
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#else
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((__u8 *)&pt1)[8] = 0xff;
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if (etags->is_deleted) {
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memset(&pt1, 0xff, 8);
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/* zero page_status byte to indicate deleted */
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((__u8 *)&pt1)[8] = 0;
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}
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#endif
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memset(&ops, 0, sizeof(ops));
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ops.mode = MTD_OOB_AUTO;
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ops.len = (data) ? chunkBytes : 0;
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ops.ooblen = YTAG1_SIZE;
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ops.datbuf = (__u8 *)data;
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ops.oobbuf = (__u8 *)&pt1;
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retval = mtd->write_oob(mtd, addr, &ops);
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if (retval) {
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T(YAFFS_TRACE_MTD,
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(TSTR("write_oob failed, chunk %d, mtd error %d"TENDSTR),
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nand_chunk, retval));
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}
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return retval ? YAFFS_FAIL : YAFFS_OK;
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}
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/* Return with empty ExtendedTags but add ecc_result.
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*/
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static int rettags(yaffs_ext_tags *etags, int ecc_result, int retval)
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{
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if (etags) {
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memset(etags, 0, sizeof(*etags));
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etags->ecc_result = ecc_result;
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}
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return retval;
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}
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/* Read a chunk (page) from NAND.
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*
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* Caller expects ExtendedTags data to be usable even on error; that is,
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* all members except ecc_result and block_bad are zeroed.
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*
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* - Check ECC results for data (if applicable)
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* - Check for blank/erased block (return empty ExtendedTags if blank)
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* - Check the PackedTags1 mini-ECC (correct if necessary/possible)
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* - Convert PackedTags1 to ExtendedTags
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* - Update ecc_result and block_bad members to refect state.
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*
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* Returns YAFFS_OK or YAFFS_FAIL.
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*/
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int nandmtd1_ReadChunkWithTagsFromNAND(yaffs_dev_t *dev,
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int nand_chunk, __u8 *data, yaffs_ext_tags *etags)
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{
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struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
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int chunkBytes = dev->data_bytes_per_chunk;
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loff_t addr = ((loff_t)nand_chunk) * chunkBytes;
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int eccres = YAFFS_ECC_RESULT_NO_ERROR;
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struct mtd_oob_ops ops;
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yaffs_PackedTags1 pt1;
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int retval;
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int deleted;
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memset(&ops, 0, sizeof(ops));
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ops.mode = MTD_OOB_AUTO;
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ops.len = (data) ? chunkBytes : 0;
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ops.ooblen = YTAG1_SIZE;
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ops.datbuf = data;
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ops.oobbuf = (__u8 *)&pt1;
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#if (MTD_VERSION_CODE < MTD_VERSION(2, 6, 20))
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/* In MTD 2.6.18 to 2.6.19 nand_base.c:nand_do_read_oob() has a bug;
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* help it out with ops.len = ops.ooblen when ops.datbuf == NULL.
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*/
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ops.len = (ops.datbuf) ? ops.len : ops.ooblen;
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#endif
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/* Read page and oob using MTD.
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* Check status and determine ECC result.
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*/
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retval = mtd->read_oob(mtd, addr, &ops);
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if (retval) {
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T(YAFFS_TRACE_MTD,
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(TSTR("read_oob failed, chunk %d, mtd error %d"TENDSTR),
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nand_chunk, retval));
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}
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switch (retval) {
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case 0:
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/* no error */
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break;
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case -EUCLEAN:
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/* MTD's ECC fixed the data */
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eccres = YAFFS_ECC_RESULT_FIXED;
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dev->n_ecc_fixed++;
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break;
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case -EBADMSG:
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/* MTD's ECC could not fix the data */
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dev->n_ecc_unfixed++;
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/* fall into... */
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default:
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rettags(etags, YAFFS_ECC_RESULT_UNFIXED, 0);
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etags->block_bad = (mtd->block_isbad)(mtd, addr);
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return YAFFS_FAIL;
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}
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/* Check for a blank/erased chunk.
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*/
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if (yaffs_check_ff((__u8 *)&pt1, 8)) {
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/* when blank, upper layers want ecc_result to be <= NO_ERROR */
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return rettags(etags, YAFFS_ECC_RESULT_NO_ERROR, YAFFS_OK);
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}
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#ifndef CONFIG_YAFFS_9BYTE_TAGS
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/* Read deleted status (bit) then return it to it's non-deleted
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* state before performing tags mini-ECC check. pt1.deleted is
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* inverted.
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*/
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deleted = !pt1.deleted;
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pt1.deleted = 1;
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#else
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deleted = (yaffs_count_bits(((__u8 *)&pt1)[8]) < 7);
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#endif
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/* Check the packed tags mini-ECC and correct if necessary/possible.
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*/
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retval = yaffs_check_tags_ecc((yaffs_tags_t *)&pt1);
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switch (retval) {
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case 0:
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/* no tags error, use MTD result */
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break;
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case 1:
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/* recovered tags-ECC error */
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dev->n_tags_ecc_fixed++;
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if (eccres == YAFFS_ECC_RESULT_NO_ERROR)
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eccres = YAFFS_ECC_RESULT_FIXED;
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break;
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default:
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/* unrecovered tags-ECC error */
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dev->n_tags_ecc_unfixed++;
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return rettags(etags, YAFFS_ECC_RESULT_UNFIXED, YAFFS_FAIL);
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}
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/* Unpack the tags to extended form and set ECC result.
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* [set shouldBeFF just to keep yaffs_unpack_tags1 happy]
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*/
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pt1.shouldBeFF = 0xFFFFFFFF;
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yaffs_unpack_tags1(etags, &pt1);
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etags->ecc_result = eccres;
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/* Set deleted state */
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etags->is_deleted = deleted;
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return YAFFS_OK;
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}
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/* Mark a block bad.
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*
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* This is a persistant state.
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* Use of this function should be rare.
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*
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* Returns YAFFS_OK or YAFFS_FAIL.
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*/
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int nandmtd1_MarkNANDBlockBad(struct yaffs_dev_s *dev, int block_no)
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{
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struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
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int blocksize = dev->param.chunks_per_block * dev->data_bytes_per_chunk;
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int retval;
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T(YAFFS_TRACE_BAD_BLOCKS,(TSTR("marking block %d bad"TENDSTR), block_no));
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retval = mtd->block_markbad(mtd, (loff_t)blocksize * block_no);
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return (retval) ? YAFFS_FAIL : YAFFS_OK;
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}
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/* Check any MTD prerequists.
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*
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* Returns YAFFS_OK or YAFFS_FAIL.
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*/
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static int nandmtd1_TestPrerequists(struct mtd_info *mtd)
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{
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/* 2.6.18 has mtd->ecclayout->oobavail */
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/* 2.6.21 has mtd->ecclayout->oobavail and mtd->oobavail */
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int oobavail = mtd->ecclayout->oobavail;
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if (oobavail < YTAG1_SIZE) {
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T(YAFFS_TRACE_ERROR,
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(TSTR("mtd device has only %d bytes for tags, need %d"TENDSTR),
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oobavail, YTAG1_SIZE));
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return YAFFS_FAIL;
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}
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return YAFFS_OK;
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}
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/* Query for the current state of a specific block.
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*
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* Examine the tags of the first chunk of the block and return the state:
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* - YAFFS_BLOCK_STATE_DEAD, the block is marked bad
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* - YAFFS_BLOCK_STATE_NEEDS_SCANNING, the block is in use
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* - YAFFS_BLOCK_STATE_EMPTY, the block is clean
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*
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* Always returns YAFFS_OK.
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*/
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int nandmtd1_QueryNANDBlock(struct yaffs_dev_s *dev, int block_no,
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yaffs_block_state_t *pState, __u32 *pSequenceNumber)
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{
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struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
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int chunkNo = block_no * dev->param.chunks_per_block;
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loff_t addr = (loff_t)chunkNo * dev->data_bytes_per_chunk;
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yaffs_ext_tags etags;
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int state = YAFFS_BLOCK_STATE_DEAD;
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int seqnum = 0;
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int retval;
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/* We don't yet have a good place to test for MTD config prerequists.
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* Do it here as we are called during the initial scan.
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*/
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if (nandmtd1_TestPrerequists(mtd) != YAFFS_OK)
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return YAFFS_FAIL;
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retval = nandmtd1_ReadChunkWithTagsFromNAND(dev, chunkNo, NULL, &etags);
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etags.block_bad = (mtd->block_isbad)(mtd, addr);
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if (etags.block_bad) {
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T(YAFFS_TRACE_BAD_BLOCKS,
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(TSTR("block %d is marked bad"TENDSTR), block_no));
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state = YAFFS_BLOCK_STATE_DEAD;
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} else if (etags.ecc_result != YAFFS_ECC_RESULT_NO_ERROR) {
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/* bad tags, need to look more closely */
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state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
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} else if (etags.chunk_used) {
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state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
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seqnum = etags.seq_number;
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} else {
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state = YAFFS_BLOCK_STATE_EMPTY;
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}
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*pState = state;
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*pSequenceNumber = seqnum;
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/* query always succeeds */
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return YAFFS_OK;
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}
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#endif /*MTD_VERSION*/
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