--- linux-2.6.27.6/fs/yaffs2/yaffs_checkptrw.c	1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6.27.6.yaffs/fs/yaffs2/yaffs_checkptrw.c	2011-05-08 18:01:08.000000000 +0800
@@ -0,0 +1,405 @@
+/*
+ * 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.
+ */
+
+const char *yaffs_checkptrw_c_version =
+	"$Id: yaffs_checkptrw.c,v 1.23 2010/02/18 01:18:04 charles Exp $";
+
+
+#include "yaffs_checkptrw.h"
+#include "yaffs_getblockinfo.h"
+
+static int yaffs_CheckpointSpaceOk(yaffs_Device *dev)
+{
+	int blocksAvailable = dev->nErasedBlocks - dev->param.nReservedBlocks;
+
+	T(YAFFS_TRACE_CHECKPOINT,
+		(TSTR("checkpt blocks available = %d" TENDSTR),
+		blocksAvailable));
+
+	return (blocksAvailable <= 0) ? 0 : 1;
+}
+
+
+static int yaffs_CheckpointErase(yaffs_Device *dev)
+{
+	int i;
+
+	if (!dev->param.eraseBlockInNAND)
+		return 0;
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("checking blocks %d to %d"TENDSTR),
+		dev->internalStartBlock, dev->internalEndBlock));
+
+	for (i = dev->internalStartBlock; i <= dev->internalEndBlock; i++) {
+		yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, i);
+		if (bi->blockState == YAFFS_BLOCK_STATE_CHECKPOINT) {
+			T(YAFFS_TRACE_CHECKPOINT, (TSTR("erasing checkpt block %d"TENDSTR), i));
+
+			dev->nBlockErasures++;
+
+			if (dev->param.eraseBlockInNAND(dev, i - dev->blockOffset /* realign */)) {
+				bi->blockState = YAFFS_BLOCK_STATE_EMPTY;
+				dev->nErasedBlocks++;
+				dev->nFreeChunks += dev->param.nChunksPerBlock;
+			} else {
+				dev->param.markNANDBlockBad(dev, i);
+				bi->blockState = YAFFS_BLOCK_STATE_DEAD;
+			}
+		}
+	}
+
+	dev->blocksInCheckpoint = 0;
+
+	return 1;
+}
+
+
+static void yaffs_CheckpointFindNextErasedBlock(yaffs_Device *dev)
+{
+	int  i;
+	int blocksAvailable = dev->nErasedBlocks - dev->param.nReservedBlocks;
+	T(YAFFS_TRACE_CHECKPOINT,
+		(TSTR("allocating checkpt block: erased %d reserved %d avail %d next %d "TENDSTR),
+		dev->nErasedBlocks, dev->param.nReservedBlocks, blocksAvailable, dev->checkpointNextBlock));
+
+	if (dev->checkpointNextBlock >= 0 &&
+			dev->checkpointNextBlock <= dev->internalEndBlock &&
+			blocksAvailable > 0) {
+
+		for (i = dev->checkpointNextBlock; i <= dev->internalEndBlock; i++) {
+			yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, i);
+			if (bi->blockState == YAFFS_BLOCK_STATE_EMPTY) {
+				dev->checkpointNextBlock = i + 1;
+				dev->checkpointCurrentBlock = i;
+				T(YAFFS_TRACE_CHECKPOINT, (TSTR("allocating checkpt block %d"TENDSTR), i));
+				return;
+			}
+		}
+	}
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("out of checkpt blocks"TENDSTR)));
+
+	dev->checkpointNextBlock = -1;
+	dev->checkpointCurrentBlock = -1;
+}
+
+static void yaffs_CheckpointFindNextCheckpointBlock(yaffs_Device *dev)
+{
+	int  i;
+	yaffs_ExtendedTags tags;
+
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("find next checkpt block: start:  blocks %d next %d" TENDSTR),
+		dev->blocksInCheckpoint, dev->checkpointNextBlock));
+
+	if (dev->blocksInCheckpoint < dev->checkpointMaxBlocks)
+		for (i = dev->checkpointNextBlock; i <= dev->internalEndBlock; i++) {
+			int chunk = i * dev->param.nChunksPerBlock;
+			int realignedChunk = chunk - dev->chunkOffset;
+
+			dev->param.readChunkWithTagsFromNAND(dev, realignedChunk,
+					NULL, &tags);
+			T(YAFFS_TRACE_CHECKPOINT, (TSTR("find next checkpt block: search: block %d oid %d seq %d eccr %d" TENDSTR),
+				i, tags.objectId, tags.sequenceNumber, tags.eccResult));
+
+			if (tags.sequenceNumber == YAFFS_SEQUENCE_CHECKPOINT_DATA) {
+				/* Right kind of block */
+				dev->checkpointNextBlock = tags.objectId;
+				dev->checkpointCurrentBlock = i;
+				dev->checkpointBlockList[dev->blocksInCheckpoint] = i;
+				dev->blocksInCheckpoint++;
+				T(YAFFS_TRACE_CHECKPOINT, (TSTR("found checkpt block %d"TENDSTR), i));
+				return;
+			}
+		}
+
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("found no more checkpt blocks"TENDSTR)));
+
+	dev->checkpointNextBlock = -1;
+	dev->checkpointCurrentBlock = -1;
+}
+
+
+int yaffs_CheckpointOpen(yaffs_Device *dev, int forWriting)
+{
+
+
+	dev->checkpointOpenForWrite = forWriting;
+
+	/* Got the functions we need? */
+	if (!dev->param.writeChunkWithTagsToNAND ||
+		!dev->param.readChunkWithTagsFromNAND ||
+		!dev->param.eraseBlockInNAND ||
+		!dev->param.markNANDBlockBad)
+		return 0;
+
+	if (forWriting && !yaffs_CheckpointSpaceOk(dev))
+		return 0;
+
+	if (!dev->checkpointBuffer)
+		dev->checkpointBuffer = YMALLOC_DMA(dev->param.totalBytesPerChunk);
+	if (!dev->checkpointBuffer)
+		return 0;
+
+
+	dev->checkpointPageSequence = 0;
+	dev->checkpointByteCount = 0;
+	dev->checkpointSum = 0;
+	dev->checkpointXor = 0;
+	dev->checkpointCurrentBlock = -1;
+	dev->checkpointCurrentChunk = -1;
+	dev->checkpointNextBlock = dev->internalStartBlock;
+
+	/* Erase all the blocks in the checkpoint area */
+	if (forWriting) {
+		memset(dev->checkpointBuffer, 0, dev->nDataBytesPerChunk);
+		dev->checkpointByteOffset = 0;
+		return yaffs_CheckpointErase(dev);
+	} else {
+		int i;
+		/* Set to a value that will kick off a read */
+		dev->checkpointByteOffset = dev->nDataBytesPerChunk;
+		/* A checkpoint block list of 1 checkpoint block per 16 block is (hopefully)
+		 * going to be way more than we need */
+		dev->blocksInCheckpoint = 0;
+		dev->checkpointMaxBlocks = (dev->internalEndBlock - dev->internalStartBlock)/16 + 2;
+		dev->checkpointBlockList = YMALLOC(sizeof(int) * dev->checkpointMaxBlocks);
+		if(!dev->checkpointBlockList)
+			return 0;
+
+		for (i = 0; i < dev->checkpointMaxBlocks; i++)
+			dev->checkpointBlockList[i] = -1;
+	}
+
+	return 1;
+}
+
+int yaffs_GetCheckpointSum(yaffs_Device *dev, __u32 *sum)
+{
+	__u32 compositeSum;
+	compositeSum =  (dev->checkpointSum << 8) | (dev->checkpointXor & 0xFF);
+	*sum = compositeSum;
+	return 1;
+}
+
+static int yaffs_CheckpointFlushBuffer(yaffs_Device *dev)
+{
+	int chunk;
+	int realignedChunk;
+
+	yaffs_ExtendedTags tags;
+
+	if (dev->checkpointCurrentBlock < 0) {
+		yaffs_CheckpointFindNextErasedBlock(dev);
+		dev->checkpointCurrentChunk = 0;
+	}
+
+	if (dev->checkpointCurrentBlock < 0)
+		return 0;
+
+	tags.chunkDeleted = 0;
+	tags.objectId = dev->checkpointNextBlock; /* Hint to next place to look */
+	tags.chunkId = dev->checkpointPageSequence + 1;
+	tags.sequenceNumber =  YAFFS_SEQUENCE_CHECKPOINT_DATA;
+	tags.byteCount = dev->nDataBytesPerChunk;
+	if (dev->checkpointCurrentChunk == 0) {
+		/* First chunk we write for the block? Set block state to
+		   checkpoint */
+		yaffs_BlockInfo *bi = yaffs_GetBlockInfo(dev, dev->checkpointCurrentBlock);
+		bi->blockState = YAFFS_BLOCK_STATE_CHECKPOINT;
+		dev->blocksInCheckpoint++;
+	}
+
+	chunk = dev->checkpointCurrentBlock * dev->param.nChunksPerBlock + dev->checkpointCurrentChunk;
+
+
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("checkpoint wite buffer nand %d(%d:%d) objid %d chId %d" TENDSTR),
+		chunk, dev->checkpointCurrentBlock, dev->checkpointCurrentChunk, tags.objectId, tags.chunkId));
+
+	realignedChunk = chunk - dev->chunkOffset;
+
+	dev->nPageWrites++;
+
+	dev->param.writeChunkWithTagsToNAND(dev, realignedChunk,
+			dev->checkpointBuffer, &tags);
+	dev->checkpointByteOffset = 0;
+	dev->checkpointPageSequence++;
+	dev->checkpointCurrentChunk++;
+	if (dev->checkpointCurrentChunk >= dev->param.nChunksPerBlock) {
+		dev->checkpointCurrentChunk = 0;
+		dev->checkpointCurrentBlock = -1;
+	}
+	memset(dev->checkpointBuffer, 0, dev->nDataBytesPerChunk);
+
+	return 1;
+}
+
+
+int yaffs_CheckpointWrite(yaffs_Device *dev, const void *data, int nBytes)
+{
+	int i = 0;
+	int ok = 1;
+
+
+	__u8 * dataBytes = (__u8 *)data;
+
+
+
+	if (!dev->checkpointBuffer)
+		return 0;
+
+	if (!dev->checkpointOpenForWrite)
+		return -1;
+
+	while (i < nBytes && ok) {
+		dev->checkpointBuffer[dev->checkpointByteOffset] = *dataBytes;
+		dev->checkpointSum += *dataBytes;
+		dev->checkpointXor ^= *dataBytes;
+
+		dev->checkpointByteOffset++;
+		i++;
+		dataBytes++;
+		dev->checkpointByteCount++;
+
+
+		if (dev->checkpointByteOffset < 0 ||
+		   dev->checkpointByteOffset >= dev->nDataBytesPerChunk)
+			ok = yaffs_CheckpointFlushBuffer(dev);
+	}
+
+	return i;
+}
+
+int yaffs_CheckpointRead(yaffs_Device *dev, void *data, int nBytes)
+{
+	int i = 0;
+	int ok = 1;
+	yaffs_ExtendedTags tags;
+
+
+	int chunk;
+	int realignedChunk;
+
+	__u8 *dataBytes = (__u8 *)data;
+
+	if (!dev->checkpointBuffer)
+		return 0;
+
+	if (dev->checkpointOpenForWrite)
+		return -1;
+
+	while (i < nBytes && ok) {
+
+
+		if (dev->checkpointByteOffset < 0 ||
+			dev->checkpointByteOffset >= dev->nDataBytesPerChunk) {
+
+			if (dev->checkpointCurrentBlock < 0) {
+				yaffs_CheckpointFindNextCheckpointBlock(dev);
+				dev->checkpointCurrentChunk = 0;
+			}
+
+			if (dev->checkpointCurrentBlock < 0)
+				ok = 0;
+			else {
+				chunk = dev->checkpointCurrentBlock *
+					dev->param.nChunksPerBlock +
+					dev->checkpointCurrentChunk;
+
+				realignedChunk = chunk - dev->chunkOffset;
+				
+				dev->nPageReads++;
+
+				/* read in the next chunk */
+				/* printf("read checkpoint page %d\n",dev->checkpointPage); */
+				dev->param.readChunkWithTagsFromNAND(dev,
+						realignedChunk,
+						dev->checkpointBuffer,
+						&tags);
+
+				if (tags.chunkId != (dev->checkpointPageSequence + 1) ||
+					tags.eccResult > YAFFS_ECC_RESULT_FIXED ||
+					tags.sequenceNumber != YAFFS_SEQUENCE_CHECKPOINT_DATA)
+					ok = 0;
+
+				dev->checkpointByteOffset = 0;
+				dev->checkpointPageSequence++;
+				dev->checkpointCurrentChunk++;
+
+				if (dev->checkpointCurrentChunk >= dev->param.nChunksPerBlock)
+					dev->checkpointCurrentBlock = -1;
+			}
+		}
+
+		if (ok) {
+			*dataBytes = dev->checkpointBuffer[dev->checkpointByteOffset];
+			dev->checkpointSum += *dataBytes;
+			dev->checkpointXor ^= *dataBytes;
+			dev->checkpointByteOffset++;
+			i++;
+			dataBytes++;
+			dev->checkpointByteCount++;
+		}
+	}
+
+	return 	i;
+}
+
+int yaffs_CheckpointClose(yaffs_Device *dev)
+{
+
+	if (dev->checkpointOpenForWrite) {
+		if (dev->checkpointByteOffset != 0)
+			yaffs_CheckpointFlushBuffer(dev);
+	} else if(dev->checkpointBlockList){
+		int i;
+		for (i = 0; i < dev->blocksInCheckpoint && dev->checkpointBlockList[i] >= 0; i++) {
+			int blk = dev->checkpointBlockList[i];
+			yaffs_BlockInfo *bi = NULL;
+			if( dev->internalStartBlock <= blk && blk <= dev->internalEndBlock)
+				bi = yaffs_GetBlockInfo(dev, blk);
+			if (bi && bi->blockState == YAFFS_BLOCK_STATE_EMPTY)
+				bi->blockState = YAFFS_BLOCK_STATE_CHECKPOINT;
+			else {
+				/* Todo this looks odd... */
+			}
+		}
+		YFREE(dev->checkpointBlockList);
+		dev->checkpointBlockList = NULL;
+	}
+
+	dev->nFreeChunks -= dev->blocksInCheckpoint * dev->param.nChunksPerBlock;
+	dev->nErasedBlocks -= dev->blocksInCheckpoint;
+
+
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("checkpoint byte count %d" TENDSTR),
+			dev->checkpointByteCount));
+
+	if (dev->checkpointBuffer) {
+		/* free the buffer */
+		YFREE(dev->checkpointBuffer);
+		dev->checkpointBuffer = NULL;
+		return 1;
+	} else
+		return 0;
+}
+
+int yaffs_CheckpointInvalidateStream(yaffs_Device *dev)
+{
+	/* Erase the checkpoint data */
+
+	T(YAFFS_TRACE_CHECKPOINT, (TSTR("checkpoint invalidate of %d blocks"TENDSTR),
+		dev->blocksInCheckpoint));
+
+	return yaffs_CheckpointErase(dev);
+}
+
+
+
