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* linux/include/linux/mtd/bbm.h
* NAND family Bad Block Management (BBM) header file
* - Bad Block Table (BBT) implementation
* Copyright © 2005 Samsung Electronics
* Kyungmin Park <>
* Copyright © 2000-2005
* Thomas Gleixner <>
* SPDX-License-Identifier: GPL-2.0+
#ifndef __LINUX_MTD_BBM_H
#define __LINUX_MTD_BBM_H
/* The maximum number of NAND chips in an array */
* struct nand_bbt_descr - bad block table descriptor
* @options: options for this descriptor
* @pages: the page(s) where we find the bbt, used with option BBT_ABSPAGE
* when bbt is searched, then we store the found bbts pages here.
* Its an array and supports up to 8 chips now
* @offs: offset of the pattern in the oob area of the page
* @veroffs: offset of the bbt version counter in the oob are of the page
* @version: version read from the bbt page during scan
* @len: length of the pattern, if 0 no pattern check is performed
* @maxblocks: maximum number of blocks to search for a bbt. This number of
* blocks is reserved at the end of the device where the tables are
* written.
* @reserved_block_code: if non-0, this pattern denotes a reserved (rather than
* bad) block in the stored bbt
* @pattern: pattern to identify bad block table or factory marked good /
* bad blocks, can be NULL, if len = 0
* Descriptor for the bad block table marker and the descriptor for the
* pattern which identifies good and bad blocks. The assumption is made
* that the pattern and the version count are always located in the oob area
* of the first block.
struct nand_bbt_descr {
int options;
int offs;
int veroffs;
uint8_t version[CONFIG_SYS_NAND_MAX_CHIPS];
int len;
int maxblocks;
int reserved_block_code;
uint8_t *pattern;
/* Options for the bad block table descriptors */
/* The number of bits used per block in the bbt on the device */
#define NAND_BBT_NRBITS_MSK 0x0000000F
#define NAND_BBT_1BIT 0x00000001
#define NAND_BBT_2BIT 0x00000002
#define NAND_BBT_4BIT 0x00000004
#define NAND_BBT_8BIT 0x00000008
/* The bad block table is in the last good block of the device */
#define NAND_BBT_LASTBLOCK 0x00000010
/* The bbt is at the given page, else we must scan for the bbt */
#define NAND_BBT_ABSPAGE 0x00000020
/* bbt is stored per chip on multichip devices */
#define NAND_BBT_PERCHIP 0x00000080
/* bbt has a version counter at offset veroffs */
#define NAND_BBT_VERSION 0x00000100
/* Create a bbt if none exists */
#define NAND_BBT_CREATE 0x00000200
* Create an empty BBT with no vendor information. Vendor's information may be
* unavailable, for example, if the NAND controller has a different data and OOB
* layout or if this information is already purged. Must be used in conjunction
#define NAND_BBT_CREATE_EMPTY 0x00000400
/* Write bbt if neccecary */
#define NAND_BBT_WRITE 0x00002000
/* Read and write back block contents when writing bbt */
#define NAND_BBT_SAVECONTENT 0x00004000
/* Search good / bad pattern on the first and the second page */
#define NAND_BBT_SCAN2NDPAGE 0x00008000
/* Search good / bad pattern on the last page of the eraseblock */
#define NAND_BBT_SCANLASTPAGE 0x00010000
* Use a flash based bad block table. By default, OOB identifier is saved in
* OOB area. This option is passed to the default bad block table function.
#define NAND_BBT_USE_FLASH 0x00020000
* Do not store flash based bad block table marker in the OOB area; store it
* in-band.
#define NAND_BBT_NO_OOB 0x00040000
* Do not write new bad block markers to OOB; useful, e.g., when ECC covers
* entire spare area. Must be used with NAND_BBT_USE_FLASH.
#define NAND_BBT_NO_OOB_BBM 0x00080000
* Flag set by nand_create_default_bbt_descr(), marking that the nand_bbt_descr
* was allocated dynamicaly and must be freed in nand_release(). Has no meaning
* in nand_chip.bbt_options.
#define NAND_BBT_DYNAMICSTRUCT 0x80000000
/* The maximum number of blocks to scan for a bbt */
* Constants for oob configuration
* Bad block scanning errors
* struct bbm_info - [GENERIC] Bad Block Table data structure
* @bbt_erase_shift: [INTERN] number of address bits in a bbt entry
* @badblockpos: [INTERN] position of the bad block marker in the oob area
* @options: options for this descriptor
* @bbt: [INTERN] bad block table pointer
* @isbad_bbt: function to determine if a block is bad
* @badblock_pattern: [REPLACEABLE] bad block scan pattern used for
* initial bad block scan
* @priv: [OPTIONAL] pointer to private bbm date
struct bbm_info {
int bbt_erase_shift;
int badblockpos;
int options;
uint8_t *bbt;
int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt);
/* TODO Add more NAND specific fileds */
struct nand_bbt_descr *badblock_pattern;
void *priv;
/* OneNAND BBT interface */
extern int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
extern int onenand_default_bbt(struct mtd_info *mtd);
#endif /* __LINUX_MTD_BBM_H */