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root/include/linux/mtd/bbm.h

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/*
 *  linux/include/linux/mtd/bbm.h
 *
 *  NAND family Bad Block Management (BBM) header file
 *    - Bad Block Table (BBT) implementation
 *
 *  Copyright (c) 2005 Samsung Electronics
 *  Kyungmin Park <kyungmin.park@samsung.com>
 *
 *  Copyright (c) 2000-2005
 *  Thomas Gleixner <tglx@linuxtronix.de>
 *
 */
#ifndef __LINUX_MTD_BBM_H
#define __LINUX_MTD_BBM_H

/* The maximum number of NAND chips in an array */
#define NAND_MAX_CHIPS          8

/**
 * 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 area 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 pages[NAND_MAX_CHIPS];
        int offs;
        int veroffs;
        uint8_t version[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
/* The bbt is at the given page, else we must scan for the bbt */
#define NAND_BBT_SEARCH         0x00000040
/* 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 axists */
#define NAND_BBT_CREATE         0x00000200
/* Search good / bad pattern through all pages of a block */
#define NAND_BBT_SCANALLPAGES   0x00000400
/* Scan block empty during good / bad block scan */
#define NAND_BBT_SCANEMPTY      0x00000800
/* Write bbt if neccecary */
#define NAND_BBT_WRITE          0x00001000
/* Read and write back block contents when writing bbt */
#define NAND_BBT_SAVECONTENT    0x00002000
/* Search good / bad pattern on the first and the second page */
#define NAND_BBT_SCAN2NDPAGE    0x00004000

/* The maximum number of blocks to scan for a bbt */
#define NAND_BBT_SCAN_MAXBLOCKS 4

/*
 * Constants for oob configuration
 */
#define ONENAND_BADBLOCK_POS    0

/*
 * Bad block scanning errors
 */
#define ONENAND_BBT_READ_ERROR          1
#define ONENAND_BBT_READ_ECC_ERROR      2
#define ONENAND_BBT_READ_FATAL_ERROR    4

/**
 * 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 */

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