--- linux-2.6.27.6/fs/yaffs2/yaffs_tagscompat.c	1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6.27.6.yaffs/fs/yaffs2/yaffs_tagscompat.c	2011-05-08 18:01:07.000000000 +0800
@@ -0,0 +1,539 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2007 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.
+ */
+
+#include "yaffs_guts.h"
+#include "yaffs_tagscompat.h"
+#include "yaffs_ecc.h"
+#include "yaffs_getblockinfo.h"
+#include "yaffs_trace.h"
+
+static void yaffs_HandleReadDataError(yaffs_Device *dev, int chunkInNAND);
+#ifdef NOTYET
+static void yaffs_CheckWrittenBlock(yaffs_Device *dev, int chunkInNAND);
+static void yaffs_HandleWriteChunkOk(yaffs_Device *dev, int chunkInNAND,
+				     const __u8 *data,
+				     const yaffs_Spare *spare);
+static void yaffs_HandleUpdateChunk(yaffs_Device *dev, int chunkInNAND,
+				    const yaffs_Spare *spare);
+static void yaffs_HandleWriteChunkError(yaffs_Device *dev, int chunkInNAND);
+#endif
+
+static const char yaffs_countBitsTable[256] = {
+	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7,
+	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8
+};
+
+int yaffs_CountBits(__u8 x)
+{
+	int retVal;
+	retVal = yaffs_countBitsTable[x];
+	return retVal;
+}
+
+/********** Tags ECC calculations  *********/
+
+void yaffs_CalcECC(const __u8 *data, yaffs_Spare *spare)
+{
+	yaffs_ECCCalculate(data, spare->ecc1);
+	yaffs_ECCCalculate(&data[256], spare->ecc2);
+}
+
+void yaffs_CalcTagsECC(yaffs_Tags *tags)
+{
+	/* Calculate an ecc */
+
+	unsigned char *b = ((yaffs_TagsUnion *) tags)->asBytes;
+	unsigned i, j;
+	unsigned ecc = 0;
+	unsigned bit = 0;
+
+	tags->ecc = 0;
+
+	for (i = 0; i < 8; i++) {
+		for (j = 1; j & 0xff; j <<= 1) {
+			bit++;
+			if (b[i] & j)
+				ecc ^= bit;
+		}
+	}
+
+	tags->ecc = ecc;
+
+}
+
+int yaffs_CheckECCOnTags(yaffs_Tags *tags)
+{
+	unsigned ecc = tags->ecc;
+
+	yaffs_CalcTagsECC(tags);
+
+	ecc ^= tags->ecc;
+
+	if (ecc && ecc <= 64) {
+		/* TODO: Handle the failure better. Retire? */
+		unsigned char *b = ((yaffs_TagsUnion *) tags)->asBytes;
+
+		ecc--;
+
+		b[ecc / 8] ^= (1 << (ecc & 7));
+
+		/* Now recvalc the ecc */
+		yaffs_CalcTagsECC(tags);
+
+		return 1;	/* recovered error */
+	} else if (ecc) {
+		/* Wierd ecc failure value */
+		/* TODO Need to do somethiong here */
+		return -1;	/* unrecovered error */
+	}
+
+	return 0;
+}
+
+/********** Tags **********/
+
+static void yaffs_LoadTagsIntoSpare(yaffs_Spare *sparePtr,
+				yaffs_Tags *tagsPtr)
+{
+	yaffs_TagsUnion *tu = (yaffs_TagsUnion *) tagsPtr;
+
+	yaffs_CalcTagsECC(tagsPtr);
+
+	sparePtr->tagByte0 = tu->asBytes[0];
+	sparePtr->tagByte1 = tu->asBytes[1];
+	sparePtr->tagByte2 = tu->asBytes[2];
+	sparePtr->tagByte3 = tu->asBytes[3];
+	sparePtr->tagByte4 = tu->asBytes[4];
+	sparePtr->tagByte5 = tu->asBytes[5];
+	sparePtr->tagByte6 = tu->asBytes[6];
+	sparePtr->tagByte7 = tu->asBytes[7];
+}
+
+static void yaffs_GetTagsFromSpare(yaffs_Device *dev, yaffs_Spare *sparePtr,
+				yaffs_Tags *tagsPtr)
+{
+	yaffs_TagsUnion *tu = (yaffs_TagsUnion *) tagsPtr;
+	int result;
+
+	tu->asBytes[0] = sparePtr->tagByte0;
+	tu->asBytes[1] = sparePtr->tagByte1;
+	tu->asBytes[2] = sparePtr->tagByte2;
+	tu->asBytes[3] = sparePtr->tagByte3;
+	tu->asBytes[4] = sparePtr->tagByte4;
+	tu->asBytes[5] = sparePtr->tagByte5;
+	tu->asBytes[6] = sparePtr->tagByte6;
+	tu->asBytes[7] = sparePtr->tagByte7;
+
+	result = yaffs_CheckECCOnTags(tagsPtr);
+	if (result > 0)
+		dev->tagsEccFixed++;
+	else if (result < 0)
+		dev->tagsEccUnfixed++;
+}
+
+static void yaffs_SpareInitialise(yaffs_Spare *spare)
+{
+	memset(spare, 0xFF, sizeof(yaffs_Spare));
+}
+
+static int yaffs_WriteChunkToNAND(struct yaffs_DeviceStruct *dev,
+				int chunkInNAND, const __u8 *data,
+				yaffs_Spare *spare)
+{
+	if (chunkInNAND < dev->param.startBlock * dev->param.nChunksPerBlock) {
+		T(YAFFS_TRACE_ERROR,
+		  (TSTR("**>> yaffs chunk %d is not valid" TENDSTR),
+		   chunkInNAND));
+		return YAFFS_FAIL;
+	}
+
+	return dev->param.writeChunkToNAND(dev, chunkInNAND, data, spare);
+}
+
+static int yaffs_ReadChunkFromNAND(struct yaffs_DeviceStruct *dev,
+				   int chunkInNAND,
+				   __u8 *data,
+				   yaffs_Spare *spare,
+				   yaffs_ECCResult *eccResult,
+				   int doErrorCorrection)
+{
+	int retVal;
+	yaffs_Spare localSpare;
+
+	if (!spare && data) {
+		/* If we don't have a real spare, then we use a local one. */
+		/* Need this for the calculation of the ecc */
+		spare = &localSpare;
+	}
+
+	if (!dev->param.useNANDECC) {
+		retVal = dev->param.readChunkFromNAND(dev, chunkInNAND, data, spare);
+		if (data && doErrorCorrection) {
+			/* Do ECC correction */
+			/* Todo handle any errors */
+			int eccResult1, eccResult2;
+			__u8 calcEcc[3];
+
+			yaffs_ECCCalculate(data, calcEcc);
+			eccResult1 =
+			    yaffs_ECCCorrect(data, spare->ecc1, calcEcc);
+			yaffs_ECCCalculate(&data[256], calcEcc);
+			eccResult2 =
+			    yaffs_ECCCorrect(&data[256], spare->ecc2, calcEcc);
+
+			if (eccResult1 > 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>yaffs ecc error fix performed on chunk %d:0"
+				    TENDSTR), chunkInNAND));
+				dev->eccFixed++;
+			} else if (eccResult1 < 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>yaffs ecc error unfixed on chunk %d:0"
+				    TENDSTR), chunkInNAND));
+				dev->eccUnfixed++;
+			}
+
+			if (eccResult2 > 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>yaffs ecc error fix performed on chunk %d:1"
+				    TENDSTR), chunkInNAND));
+				dev->eccFixed++;
+			} else if (eccResult2 < 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>yaffs ecc error unfixed on chunk %d:1"
+				    TENDSTR), chunkInNAND));
+				dev->eccUnfixed++;
+			}
+
+			if (eccResult1 || eccResult2) {
+				/* We had a data problem on this page */
+				yaffs_HandleReadDataError(dev, chunkInNAND);
+			}
+
+			if (eccResult1 < 0 || eccResult2 < 0)
+				*eccResult = YAFFS_ECC_RESULT_UNFIXED;
+			else if (eccResult1 > 0 || eccResult2 > 0)
+				*eccResult = YAFFS_ECC_RESULT_FIXED;
+			else
+				*eccResult = YAFFS_ECC_RESULT_NO_ERROR;
+		}
+	} else {
+		/* Must allocate enough memory for spare+2*sizeof(int) */
+		/* for ecc results from device. */
+		struct yaffs_NANDSpare nspare;
+
+		memset(&nspare, 0, sizeof(nspare));
+
+		retVal = dev->param.readChunkFromNAND(dev, chunkInNAND, data,
+					(yaffs_Spare *) &nspare);
+		memcpy(spare, &nspare, sizeof(yaffs_Spare));
+		if (data && doErrorCorrection) {
+			if (nspare.eccres1 > 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>mtd ecc error fix performed on chunk %d:0"
+				    TENDSTR), chunkInNAND));
+			} else if (nspare.eccres1 < 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>mtd ecc error unfixed on chunk %d:0"
+				    TENDSTR), chunkInNAND));
+			}
+
+			if (nspare.eccres2 > 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>mtd ecc error fix performed on chunk %d:1"
+				    TENDSTR), chunkInNAND));
+			} else if (nspare.eccres2 < 0) {
+				T(YAFFS_TRACE_ERROR,
+				  (TSTR
+				   ("**>>mtd ecc error unfixed on chunk %d:1"
+				    TENDSTR), chunkInNAND));
+			}
+
+			if (nspare.eccres1 || nspare.eccres2) {
+				/* We had a data problem on this page */
+				yaffs_HandleReadDataError(dev, chunkInNAND);
+			}
+
+			if (nspare.eccres1 < 0 || nspare.eccres2 < 0)
+				*eccResult = YAFFS_ECC_RESULT_UNFIXED;
+			else if (nspare.eccres1 > 0 || nspare.eccres2 > 0)
+				*eccResult = YAFFS_ECC_RESULT_FIXED;
+			else
+				*eccResult = YAFFS_ECC_RESULT_NO_ERROR;
+
+		}
+	}
+	return retVal;
+}
+
+#ifdef NOTYET
+static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,
+				  int chunkInNAND)
+{
+	static int init;
+	static __u8 cmpbuf[YAFFS_BYTES_PER_CHUNK];
+	static __u8 data[YAFFS_BYTES_PER_CHUNK];
+	/* Might as well always allocate the larger size for */
+	/* dev->param.useNANDECC == true; */
+	static __u8 spare[sizeof(struct yaffs_NANDSpare)];
+
+	dev->param.readChunkFromNAND(dev, chunkInNAND, data, (yaffs_Spare *) spare);
+
+	if (!init) {
+		memset(cmpbuf, 0xff, YAFFS_BYTES_PER_CHUNK);
+		init = 1;
+	}
+
+	if (memcmp(cmpbuf, data, YAFFS_BYTES_PER_CHUNK))
+		return YAFFS_FAIL;
+	if (memcmp(cmpbuf, spare, 16))
+		return YAFFS_FAIL;
+
+	return YAFFS_OK;
+
+}
+#endif
+
+/*
+ * Functions for robustisizing
+ */
+
+static void yaffs_HandleReadDataError(yaffs_Device *dev, int chunkInNAND)
+{
+	int blockInNAND = chunkInNAND / dev->param.nChunksPerBlock;
+
+	/* Mark the block for retirement */
+	yaffs_GetBlockInfo(dev, blockInNAND + dev->blockOffset)->needsRetiring = 1;
+	T(YAFFS_TRACE_ERROR | YAFFS_TRACE_BAD_BLOCKS,
+	  (TSTR("**>>Block %d marked for retirement" TENDSTR), blockInNAND));
+
+	/* TODO:
+	 * Just do a garbage collection on the affected block
+	 * then retire the block
+	 * NB recursion
+	 */
+}
+
+#ifdef NOTYET
+static void yaffs_CheckWrittenBlock(yaffs_Device *dev, int chunkInNAND)
+{
+}
+
+static void yaffs_HandleWriteChunkOk(yaffs_Device *dev, int chunkInNAND,
+				     const __u8 *data,
+				     const yaffs_Spare *spare)
+{
+}
+
+static void yaffs_HandleUpdateChunk(yaffs_Device *dev, int chunkInNAND,
+				    const yaffs_Spare *spare)
+{
+}
+
+static void yaffs_HandleWriteChunkError(yaffs_Device *dev, int chunkInNAND)
+{
+	int blockInNAND = chunkInNAND / dev->param.nChunksPerBlock;
+
+	/* Mark the block for retirement */
+	yaffs_GetBlockInfo(dev, blockInNAND)->needsRetiring = 1;
+	/* Delete the chunk */
+	yaffs_DeleteChunk(dev, chunkInNAND, 1, __LINE__);
+}
+
+static int yaffs_VerifyCompare(const __u8 *d0, const __u8 *d1,
+			       const yaffs_Spare *s0, const yaffs_Spare *s1)
+{
+
+	if (memcmp(d0, d1, YAFFS_BYTES_PER_CHUNK) != 0 ||
+	    s0->tagByte0 != s1->tagByte0 ||
+	    s0->tagByte1 != s1->tagByte1 ||
+	    s0->tagByte2 != s1->tagByte2 ||
+	    s0->tagByte3 != s1->tagByte3 ||
+	    s0->tagByte4 != s1->tagByte4 ||
+	    s0->tagByte5 != s1->tagByte5 ||
+	    s0->tagByte6 != s1->tagByte6 ||
+	    s0->tagByte7 != s1->tagByte7 ||
+	    s0->ecc1[0] != s1->ecc1[0] ||
+	    s0->ecc1[1] != s1->ecc1[1] ||
+	    s0->ecc1[2] != s1->ecc1[2] ||
+	    s0->ecc2[0] != s1->ecc2[0] ||
+	    s0->ecc2[1] != s1->ecc2[1] || s0->ecc2[2] != s1->ecc2[2]) {
+		return 0;
+	}
+
+	return 1;
+}
+#endif				/* NOTYET */
+
+int yaffs_TagsCompatabilityWriteChunkWithTagsToNAND(yaffs_Device *dev,
+						int chunkInNAND,
+						const __u8 *data,
+						const yaffs_ExtendedTags *eTags)
+{
+	yaffs_Spare spare;
+	yaffs_Tags tags;
+
+	yaffs_SpareInitialise(&spare);
+
+	if (eTags->chunkDeleted)
+		spare.pageStatus = 0;
+	else {
+		tags.objectId = eTags->objectId;
+		tags.chunkId = eTags->chunkId;
+
+		tags.byteCountLSB = eTags->byteCount & 0x3ff;
+
+		if (dev->nDataBytesPerChunk >= 1024)
+			tags.byteCountMSB = (eTags->byteCount >> 10) & 3;
+		else
+			tags.byteCountMSB = 3;
+
+
+		tags.serialNumber = eTags->serialNumber;
+
+		if (!dev->param.useNANDECC && data)
+			yaffs_CalcECC(data, &spare);
+
+		yaffs_LoadTagsIntoSpare(&spare, &tags);
+
+	}
+
+	return yaffs_WriteChunkToNAND(dev, chunkInNAND, data, &spare);
+}
+
+int yaffs_TagsCompatabilityReadChunkWithTagsFromNAND(yaffs_Device *dev,
+						     int chunkInNAND,
+						     __u8 *data,
+						     yaffs_ExtendedTags *eTags)
+{
+
+	yaffs_Spare spare;
+	yaffs_Tags tags;
+	yaffs_ECCResult eccResult = YAFFS_ECC_RESULT_UNKNOWN;
+
+	static yaffs_Spare spareFF;
+	static int init;
+
+	if (!init) {
+		memset(&spareFF, 0xFF, sizeof(spareFF));
+		init = 1;
+	}
+
+	if (yaffs_ReadChunkFromNAND
+	    (dev, chunkInNAND, data, &spare, &eccResult, 1)) {
+		/* eTags may be NULL */
+		if (eTags) {
+
+			int deleted =
+			    (yaffs_CountBits(spare.pageStatus) < 7) ? 1 : 0;
+
+			eTags->chunkDeleted = deleted;
+			eTags->eccResult = eccResult;
+			eTags->blockBad = 0;	/* We're reading it */
+			/* therefore it is not a bad block */
+			eTags->chunkUsed =
+			    (memcmp(&spareFF, &spare, sizeof(spareFF)) !=
+			     0) ? 1 : 0;
+
+			if (eTags->chunkUsed) {
+				yaffs_GetTagsFromSpare(dev, &spare, &tags);
+
+				eTags->objectId = tags.objectId;
+				eTags->chunkId = tags.chunkId;
+				eTags->byteCount = tags.byteCountLSB;
+
+				if (dev->nDataBytesPerChunk >= 1024)
+					eTags->byteCount |= (((unsigned) tags.byteCountMSB) << 10);
+
+				eTags->serialNumber = tags.serialNumber;
+			}
+		}
+
+		return YAFFS_OK;
+	} else {
+		return YAFFS_FAIL;
+	}
+}
+
+int yaffs_TagsCompatabilityMarkNANDBlockBad(struct yaffs_DeviceStruct *dev,
+					    int blockInNAND)
+{
+
+	yaffs_Spare spare;
+
+	memset(&spare, 0xff, sizeof(yaffs_Spare));
+
+	spare.blockStatus = 'Y';
+
+	yaffs_WriteChunkToNAND(dev, blockInNAND * dev->param.nChunksPerBlock, NULL,
+			       &spare);
+	yaffs_WriteChunkToNAND(dev, blockInNAND * dev->param.nChunksPerBlock + 1,
+			       NULL, &spare);
+
+	return YAFFS_OK;
+
+}
+
+int yaffs_TagsCompatabilityQueryNANDBlock(struct yaffs_DeviceStruct *dev,
+					  int blockNo,
+					  yaffs_BlockState *state,
+					  __u32 *sequenceNumber)
+{
+
+	yaffs_Spare spare0, spare1;
+	static yaffs_Spare spareFF;
+	static int init;
+	yaffs_ECCResult dummy;
+
+	if (!init) {
+		memset(&spareFF, 0xFF, sizeof(spareFF));
+		init = 1;
+	}
+
+	*sequenceNumber = 0;
+
+	yaffs_ReadChunkFromNAND(dev, blockNo * dev->param.nChunksPerBlock, NULL,
+				&spare0, &dummy, 1);
+	yaffs_ReadChunkFromNAND(dev, blockNo * dev->param.nChunksPerBlock + 1, NULL,
+				&spare1, &dummy, 1);
+
+	if (yaffs_CountBits(spare0.blockStatus & spare1.blockStatus) < 7)
+		*state = YAFFS_BLOCK_STATE_DEAD;
+	else if (memcmp(&spareFF, &spare0, sizeof(spareFF)) == 0)
+		*state = YAFFS_BLOCK_STATE_EMPTY;
+	else
+		*state = YAFFS_BLOCK_STATE_NEEDS_SCANNING;
+
+	return YAFFS_OK;
+}
