text: /*
   *  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
  
  /**
   * 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 */
  