📄 yaffs_tagscompat.c
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/*
* YAFFS: Yet another FFS. A NAND-flash specific file system.
* yaffs_tagscompat.h: Tags compatability layer to use YAFFS1 formatted NAND.
*
* Copyright (C) 2002 Aleph One Ltd.
*
* 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.
*
* $Id: yaffs_tagscompat.c,v 1.1 2004/11/03 08:14:07 charles Exp $
*/
#include "yaffs_guts.h"
#include "yaffs_tagscompat.h"
#include "yaffs_ecc.h"
static void yaffs_HandleReadDataError(yaffs_Device *dev,int chunkInNAND);
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);
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
};
static 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->startBlock * dev->nChunksPerBlock)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>> yaffs chunk %d is not valid" TENDSTR),chunkInNAND));
return YAFFS_FAIL;
}
dev->nPageWrites++;
return dev->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;
dev->nPageReads++;
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->useNANDECC)
{
retVal = dev->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("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
dev->eccFixed++;
}
else if(eccResult1<0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
dev->eccUnfixed++;
}
if(eccResult2>0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
dev->eccFixed++;
}
else if(eccResult2<0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
dev->eccUnfixed++;
}
if(eccResult1 || eccResult2)
{
// Hoosterman, 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;
retVal = dev->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("**>>ecc error fix performed on chunk %d:0" TENDSTR),chunkInNAND));
}
else if(nspare.eccres1<0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:0" TENDSTR),chunkInNAND));
}
if(nspare.eccres2>0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error fix performed on chunk %d:1" TENDSTR),chunkInNAND));
}
else if(nspare.eccres2<0)
{
T(YAFFS_TRACE_ERROR,(TSTR("**>>ecc error unfixed on chunk %d:1" TENDSTR),chunkInNAND));
}
if(nspare.eccres1 || nspare.eccres2)
{
// Hoosterman, 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;
}
static int yaffs_CheckChunkErased(struct yaffs_DeviceStruct *dev,int chunkInNAND)
{
static int init = 0;
static __u8 cmpbuf[YAFFS_BYTES_PER_CHUNK];
static __u8 data[YAFFS_BYTES_PER_CHUNK];
// Might as well always allocate the larger size for dev->useNANDECC == true;
static __u8 spare[sizeof(struct yaffs_NANDSpare)];
dev->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;
}
#if 0
int yaffs_EraseBlockInNAND(struct yaffs_DeviceStruct *dev,int blockInNAND)
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