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 option BBT_ABSPAGE
  24  *              when bbt is searched, then we store the found bbts pages here.
  25  *              Its an array and supports up to 8 chips now
  26  * @offs:       offset of the pattern in the oob area of the page
  27  * @veroffs:    offset of the bbt version counter in the oob are of the page
  28  * @version:    version read from the bbt page during scan
  29  * @len:        length of the pattern, if 0 no pattern check is performed
  30  * @maxblocks:  maximum number of blocks to search for a bbt. This number of
  31  *              blocks is reserved at the end of the device where the tables are
  32  *              written.
  33  * @reserved_block_code: if non-0, this pattern denotes a reserved (rather than
  34  *              bad) block in the stored bbt
  35  * @pattern:    pattern to identify bad block table or factory marked good /
  36  *              bad blocks, can be NULL, if len = 0
  37  *
  38  * Descriptor for the bad block table marker and the descriptor for the
  39  * pattern which identifies good and bad blocks. The assumption is made
  40  * that the pattern and the version count are always located in the oob area
  41  * of the first block.
  42  */
  43 struct nand_bbt_descr {
  44         int options;
  45         int pages[NAND_MAX_CHIPS];
  46         int offs;
  47         int veroffs;
  48         uint8_t version[NAND_MAX_CHIPS];
  49         int len;
  50         int maxblocks;
  51         int reserved_block_code;
  52         uint8_t *pattern;
  53 };
  54
  55 /* Options for the bad block table descriptors */
  56
  57 /* The number of bits used per block in the bbt on the device */
  58 #define NAND_BBT_NRBITS_MSK     0x0000000F
  59 #define NAND_BBT_1BIT           0x00000001
  60 #define NAND_BBT_2BIT           0x00000002
  61 #define NAND_BBT_4BIT           0x00000004
  62 #define NAND_BBT_8BIT           0x00000008
  63 /* The bad block table is in the last good block of the device */
  64 #define NAND_BBT_LASTBLOCK      0x00000010
  65 /* The bbt is at the given page, else we must scan for the bbt */
  66 #define NAND_BBT_ABSPAGE        0x00000020
  67 /* The bbt is at the given page, else we must scan for the bbt */
  68 #define NAND_BBT_SEARCH         0x00000040
  69 /* bbt is stored per chip on multichip devices */
  70 #define NAND_BBT_PERCHIP        0x00000080
  71 /* bbt has a version counter at offset veroffs */
  72 #define NAND_BBT_VERSION        0x00000100
  73 /* Create a bbt if none axists */
  74 #define NAND_BBT_CREATE         0x00000200
  75 /* Search good / bad pattern through all pages of a block */
  76 #define NAND_BBT_SCANALLPAGES   0x00000400
  77 /* Scan block empty during good / bad block scan */
  78 #define NAND_BBT_SCANEMPTY      0x00000800
  79 /* Write bbt if neccecary */
  80 #define NAND_BBT_WRITE          0x00001000
  81 /* Read and write back block contents when writing bbt */
  82 #define NAND_BBT_SAVECONTENT    0x00002000
  83 /* Search good / bad pattern on the first and the second page */
  84 #define NAND_BBT_SCAN2NDPAGE    0x00004000
  85
  86 /* The maximum number of blocks to scan for a bbt */
  87 #define NAND_BBT_SCAN_MAXBLOCKS 4
  88
  89 /*
  90  * Constants for oob configuration
  91  */
  92 #define NAND_SMALL_BADBLOCK_POS         5
  93 #define NAND_LARGE_BADBLOCK_POS         0
  94 #define ONENAND_BADBLOCK_POS            0
  95
  96 /*
  97  * Bad block scanning errors
  98  */
  99 #define ONENAND_BBT_READ_ERROR          1
 100 #define ONENAND_BBT_READ_ECC_ERROR      2
 101 #define ONENAND_BBT_READ_FATAL_ERROR    4
 102
 103 /**
 104  * struct bbm_info - [GENERIC] Bad Block Table data structure
 105  * @bbt_erase_shift:    [INTERN] number of address bits in a bbt entry
 106  * @badblockpos:        [INTERN] position of the bad block marker in the oob area
 107  * @options:            options for this descriptor
 108  * @bbt:                [INTERN] bad block table pointer
 109  * @isbad_bbt:          function to determine if a block is bad
 110  * @badblock_pattern:   [REPLACEABLE] bad block scan pattern used for
 111  *                      initial bad block scan
 112  * @priv:               [OPTIONAL] pointer to private bbm date
 113  */
 114 struct bbm_info {
 115         int bbt_erase_shift;
 116         int badblockpos;
 117         int options;
 118
 119         uint8_t *bbt;
 120
 121         int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt);
 122
 123         /* TODO Add more NAND specific fileds */
 124         struct nand_bbt_descr *badblock_pattern;
 125
 126         void *priv;
 127 };
 128
 129 /* OneNAND BBT interface */
 130 extern int onenand_scan_bbt(struct mtd_info *mtd, struct nand_bbt_descr *bd);
 131 extern int onenand_default_bbt(struct mtd_info *mtd);
 132
 133 #endif  /* __LINUX_MTD_BBM_H */