include/linux/mtd/bbm.h

   1 /*
   2  *  linux/include/linux/mtd/bbm.h
   3  *
   4  *  NAND family Bad Block Management (BBM) header file
   5  *    - Bad Block Table (BBT) implementation
   6  *
   7  *  Copyright (c) 2005 Samsung Electronics
   8  *  Kyungmin Park <kyungmin.park@samsung.com>
   9  *
  10  *  Copyright (c) 2000-2005
  11  *  Thomas Gleixner <tglx@linuxtronix.de>
  12  *
  13  */
  14 #ifndef __LINUX_MTD_BBM_H
  15 #define __LINUX_MTD_BBM_H
  16
  17 /* The maximum number of NAND chips in an array */
  18 #define NAND_MAX_CHIPS          8
  19
  20 /**
  21  * struct nand_bbt_descr - bad block table descriptor
  22  * @options:            options for this descriptor
  23  * @pages:              the page(s) where we find the bbt, used with
  24  *                      option BBT_ABSPAGE when bbt is searched,
  25  *                      then we store the found bbts pages here.
  26  *                      Its an array and supports up to 8 chips now
  27  * @offs:               offset of the pattern in the oob area of the page
  28  * @veroffs:            offset of the bbt version counter in the oob area of the page
  29  * @version:            version read from the bbt page during scan
  30  * @len:                length of the pattern, if 0 no pattern check is performed
  31  * @maxblocks:          maximum number of blocks to search for a bbt. This
  32  *                      number of blocks is reserved at the end of the device
  33  *                      where the tables are written.
  34  * @reserved_block_code: if non-0, this pattern denotes a reserved
  35  *                      (rather than bad) block in the stored bbt
  36  * @pattern:            pattern to identify bad block table or factory marked
  37  *                      good / bad blocks, can be NULL, if len = 0
  38  *
  39  * Descriptor for the bad block table marker and the descriptor for the
  40  * pattern which identifies good and bad blocks. The assumption is made
  41  * that the pattern and the version count are always located in the oob area
  42  * of the first block.
  43  */
  44 struct nand_bbt_descr {
  45         int options;
  46         int pages[NAND_MAX_CHIPS];
  47         int offs;
  48         int veroffs;
  49         uint8_t version[NAND_MAX_CHIPS];
  50         int len;
  51         int maxblocks;
  52         int reserved_block_code;
  53         uint8_t *pattern;
  54 };
  55
  56 /* Options for the bad block table descriptors */
  57
  58 /* The number of bits used per block in the bbt on the device */
  59 #define NAND_BBT_NRBITS_MSK     0x0000000F
  60 #define NAND_BBT_1BIT           0x00000001
  61 #define NAND_BBT_2BIT           0x00000002
  62 #define NAND_BBT_4BIT           0x00000004
  63 #define NAND_BBT_8BIT           0x00000008
  64 /* The bad block table is in the last good block of the device */
  65 #define NAND_BBT_LASTBLOCK      0x00000010
  66 /* The bbt is at the given page, else we must scan for the bbt */
  67 #define NAND_BBT_ABSPAGE        0x00000020
  68 /* The bbt is at the given page, else we must scan for the bbt */
  69 #define NAND_BBT_SEARCH         0x00000040
  70 /* bbt is stored per chip on multichip devices */
  71 #define NAND_BBT_PERCHIP        0x00000080
  72 /* bbt has a version counter at offset veroffs */
  73 #define NAND_BBT_VERSION        0x00000100
  74 /* Create a bbt if none axists */
  75 #define NAND_BBT_CREATE         0x00000200
  76 /* Search good / bad pattern through all pages of a block */
  77 #define NAND_BBT_SCANALLPAGES   0x00000400
  78 /* Scan block empty during good / bad block scan */
  79 #define NAND_BBT_SCANEMPTY      0x00000800
  80 /* Write bbt if neccecary */
  81 #define NAND_BBT_WRITE          0x00001000
  82 /* Read and write back block contents when writing bbt */
  83 #define NAND_BBT_SAVECONTENT    0x00002000
  84 /* Search good / bad pattern on the first and the second page */
  85 #define NAND_BBT_SCAN2NDPAGE    0x00004000
  86
  87 /* The maximum number of blocks to scan for a bbt */
  88 #define NAND_BBT_SCAN_MAXBLOCKS 4
  89
  90 /*
  91  * Constants for oob configuration
  92  */
  93 #define ONENAND_BADBLOCK_POS    0
  94
  95 /**
  96  * struct bbm_info - [GENERIC] Bad Block Table data structure
  97  * @bbt_erase_shift:    [INTERN] number of address bits in a bbt entry
  98  * @badblockpos:        [INTERN] position of the bad block marker in the oob area
  99  * @options:            options for this descriptor
 100  * @bbt:                [INTERN] bad block table pointer
 101  * @isbad_bbt:          function to determine if a block is bad
 102  * @badblock_pattern:   [REPLACEABLE] bad block scan pattern used for
 103  *                      initial bad block scan
 104  * @priv:               [OPTIONAL] pointer to private bbm date
 105  */
 106 struct bbm_info {
 107         int bbt_erase_shift;
 108         int badblockpos;
 109         int options;
 110
 111         uint8_t *bbt;
 112
 113         int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt);
 114
 115         /* TODO Add more NAND specific fileds */
 116         struct nand_bbt_descr *badblock_pattern;
 117
 118         void *priv;
 119 };
 120
 121 /* OneNAND BBT interface */
 122 extern int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
 123 extern int onenand_default_bbt(struct mtd_info *mtd);
 124
 125 #endif  /* __LINUX_MTD_BBM_H */