/* * 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_guts.h"#include "yaffs_packedtags1.h"#include "yaffs_tagscompat.h"	// for yaffs_CalcTagsECC#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 (LINUX_VERSION_CODE > KERNEL_VERSION(2,6,17))const char *yaffs_mtdif1_c_version = "$Id: yaffs_mtdif1.c,v 1.2 2007/07/23 19:14:04 imcd 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 = dev->genericDevice;	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);	dev->nPageWrites++;	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 = dev->genericDevice;	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;	dev->nPageReads++;	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 (LINUX_VERSION_CODE < KERNEL_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 = dev->genericDevice;	int blocksize = dev->nChunksPerBlock * dev->nDataBytesPerChunk;	int retval;	yaffs_trace(YAFFS_TRACE_BAD_BLOCKS, "marking block %d bad", 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, int *pSequenceNumber){	struct mtd_info * mtd = dev->genericDevice;	int chunkNo = blockNo * dev->nChunksPerBlock;	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);	if (etags.blockBad) {		yaffs_trace(YAFFS_TRACE_BAD_BLOCKS,			"block %d is marked bad", blockNo);		state = YAFFS_BLOCK_STATE_DEAD;	}	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 /*KERNEL_VERSION*/