/* *  linux/drivers/mtd/onenand/onenand_bbt.c * *  Bad Block Table support for the OneNAND driver * *  Copyright(c) 2005-2007 Samsung Electronics *  Kyungmin Park <kyungmin.park@samsung.com> * *  TODO: *    Split BBT core and chip specific BBT. * * 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 <common.h>#ifdef CONFIG_CMD_ONENAND#include <linux/mtd/compat.h>#include <linux/mtd/mtd.h>#include <linux/mtd/onenand.h>#include <malloc.h>#include <asm/errno.h>/** * check_short_pattern - [GENERIC] check if a pattern is in the buffer * @param buf		the buffer to search * @param len		the length of buffer to search * @param paglen	the pagelength * @param td		search pattern descriptor * * Check for a pattern at the given place. Used to search bad block * tables and good / bad block identifiers. Same as check_pattern, but * no optional empty check and the pattern is expected to start * at offset 0. */static int check_short_pattern(uint8_t * buf, int len, int paglen,			       struct nand_bbt_descr *td){	int i;	uint8_t *p = buf;	/* Compare the pattern */	for (i = 0; i < td->len; i++) {		if (p[i] != td->pattern[i])			return -1;	}	return 0;}/** * create_bbt - [GENERIC] Create a bad block table by scanning the device * @param mtd		MTD device structure * @param buf		temporary buffer * @param bd		descriptor for the good/bad block search pattern * @param chip		create the table for a specific chip, -1 read all chips. *              Applies only if NAND_BBT_PERCHIP option is set * * Create a bad block table by scanning the device * for the given good/bad block identify pattern */static int create_bbt(struct mtd_info *mtd, uint8_t * buf,		      struct nand_bbt_descr *bd, int chip){	struct onenand_chip *this = mtd->priv;	struct bbm_info *bbm = this->bbm;	int i, j, numblocks, len, scanlen;	int startblock;	loff_t from;	size_t readlen, ooblen;	printk(KERN_INFO "Scanning device for bad blocks\n");	len = 1;	/* We need only read few bytes from the OOB area */	scanlen = ooblen = 0;	readlen = bd->len;	/* chip == -1 case only */	/* Note that numblocks is 2 * (real numblocks) here;	 * see i += 2 below as it makses shifting and masking less painful	 */	numblocks = mtd->size >> (bbm->bbt_erase_shift - 1);	startblock = 0;	from = 0;	for (i = startblock; i < numblocks;) {		int ret;		for (j = 0; j < len; j++) {			size_t retlen;			/* No need to read pages fully,			 * just read required OOB bytes */			ret = onenand_read_oob(mtd,					     from + j * mtd->oobblock +					     bd->offs, readlen, &retlen,					     &buf[0]);			if (ret && ret != -EAGAIN) {				printk("ret = %d\n", ret);				return ret;			}			if (check_short_pattern			    (&buf[j * scanlen], scanlen, mtd->oobblock, bd)) {				bbm->bbt[i >> 3] |= 0x03 << (i & 0x6);				printk(KERN_WARNING				       "Bad eraseblock %d at 0x%08x\n", i >> 1,				       (unsigned int)from);				break;			}		}		i += 2;		from += (1 << bbm->bbt_erase_shift);	}	return 0;}/** * onenand_memory_bbt - [GENERIC] create a memory based bad block table * @param mtd		MTD device structure * @param bd		descriptor for the good/bad block search pattern * * The function creates a memory based bbt by scanning the device * for manufacturer / software marked good / bad blocks */static inline int onenand_memory_bbt(struct mtd_info *mtd,				     struct nand_bbt_descr *bd){	unsigned char data_buf[MAX_ONENAND_PAGESIZE];	bd->options &= ~NAND_BBT_SCANEMPTY;	return create_bbt(mtd, data_buf, bd, -1);}/** * onenand_isbad_bbt - [OneNAND Interface] Check if a block is bad * @param mtd		MTD device structure * @param offs		offset in the device * @param allowbbt	allow access to bad block table region */static int onenand_isbad_bbt(struct mtd_info *mtd, loff_t offs, int allowbbt){	struct onenand_chip *this = mtd->priv;	struct bbm_info *bbm = this->bbm;	int block;	uint8_t res;	/* Get block number * 2 */	block = (int)(offs >> (bbm->bbt_erase_shift - 1));	res = (bbm->bbt[block >> 3] >> (block & 0x06)) & 0x03;	DEBUG(MTD_DEBUG_LEVEL2,	      "onenand_isbad_bbt: bbt info for offs 0x%08x: (block %d) 0x%02x\n",	      (unsigned int)offs, block >> 1, res);	switch ((int)res) {	case 0x00:		return 0;	case 0x01:		return 1;	case 0x02:		return allowbbt ? 0 : 1;	}	return 1;}/** * onenand_scan_bbt - [OneNAND Interface] scan, find, read and maybe create bad block table(s) * @param mtd		MTD device structure * @param bd		descriptor for the good/bad block search pattern * * The function checks, if a bad block table(s) is/are already * available. If not it scans the device for manufacturer * marked good / bad blocks and writes the bad block table(s) to * the selected place. * * The bad block table memory is allocated here. It must be freed * by calling the onenand_free_bbt function. * */int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd){	struct onenand_chip *this = mtd->priv;	struct bbm_info *bbm = this->bbm;	int len, ret = 0;	len = mtd->size >> (this->erase_shift + 2);	/* Allocate memory (2bit per block) */	bbm->bbt = malloc(len);	if (!bbm->bbt) {		printk(KERN_ERR "onenand_scan_bbt: Out of memory\n");		return -ENOMEM;	}	/* Clear the memory bad block table */	memset(bbm->bbt, 0x00, len);	/* Set the bad block position */	bbm->badblockpos = ONENAND_BADBLOCK_POS;	/* Set erase shift */	bbm->bbt_erase_shift = this->erase_shift;	if (!bbm->isbad_bbt)		bbm->isbad_bbt = onenand_isbad_bbt;	/* Scan the device to build a memory based bad block table */	if ((ret = onenand_memory_bbt(mtd, bd))) {		printk(KERN_ERR		       "onenand_scan_bbt: Can't scan flash and build the RAM-based BBT\n");		free(bbm->bbt);		bbm->bbt = NULL;	}	return ret;}/* * Define some generic bad / good block scan pattern which are used * while scanning a device for factory marked good / bad blocks. */static uint8_t scan_ff_pattern[] = { 0xff, 0xff };static struct nand_bbt_descr largepage_memorybased = {	.options = 0,	.offs = 0,	.len = 2,	.pattern = scan_ff_pattern,};/** * onenand_default_bbt - [OneNAND Interface] Select a default bad block table for the device * @param mtd		MTD device structure * * This function selects the default bad block table * support for the device and calls the onenand_scan_bbt function */int onenand_default_bbt(struct mtd_info *mtd){	struct onenand_chip *this = mtd->priv;	struct bbm_info *bbm;	this->bbm = malloc(sizeof(struct bbm_info));	if (!this->bbm)		return -ENOMEM;	bbm = this->bbm;	memset(bbm, 0, sizeof(struct bbm_info));	/* 1KB page has same configuration as 2KB page */	if (!bbm->badblock_pattern)		bbm->badblock_pattern = &largepage_memorybased;	return onenand_scan_bbt(mtd, bbm->badblock_pattern);}#endif /* CFG_CMD_ONENAND */