--- linux-2.6.27.6/fs/yaffs2/yaffs_mtdif1.c	1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6.27.6.yaffs/fs/yaffs2/yaffs_mtdif1.c	2011-05-08 18:01:07.000000000 +0800
@@ -0,0 +1,363 @@
+/*
+ * 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_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))
+
+const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.13 2010/02/18 01:18:04 charles 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 = yaffs_DeviceToContext(dev)->mtd;
+	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) {
+		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 = yaffs_DeviceToContext(dev)->mtd;
+	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) {
+		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 = yaffs_DeviceToContext(dev)->mtd;
+	int blocksize = dev->param.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, __u32 *pSequenceNumber)
+{
+	struct mtd_info *mtd = yaffs_DeviceToContext(dev)->mtd;
+	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) {
+		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 /*MTD_VERSION*/
