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) 2005-2007 Samsung Electronics
   8  *  Kyungmin Park <kyungmin.park@samsung.com>
   9  *
  10  *  Copyright (c) 2000-2005
  11  *  Thomas Gleixner <tglx@linuxtronix.de>
  12  *
  13  * This program is free software; you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License version 2 as
  15  * published by the Free Software Foundation.
  16  */
  17 #ifndef __LINUX_MTD_BBM_H
  18 #define __LINUX_MTD_BBM_H
  19
  20 /* The maximum number of NAND chips in an array */
  21 #ifndef NAND_MAX_CHIPS
  22 #define NAND_MAX_CHIPS          8
  23 #endif
  24
  25 /**
  26  * struct nand_bbt_descr - bad block table descriptor
  27  * @param options       options for this descriptor
  28  * @param pages         the page(s) where we find the bbt, used with
  29  *                      option BBT_ABSPAGE when bbt is searched,
  30  *                      then we store the found bbts pages here.
  31  *                      Its an array and supports up to 8 chips now
  32  * @param offs          offset of the pattern in the oob area of the page
  33  * @param veroffs       offset of the bbt version counter in the oob are of the page
  34  * @param version       version read from the bbt page during scan
  35  * @param len           length of the pattern, if 0 no pattern check is performed
  36  * @param maxblocks     maximum number of blocks to search for a bbt. This number of
  37  *                      blocks is reserved at the end of the device
  38  *                      where the tables are written.
  39  * @param reserved_block_code   if non-0, this pattern denotes a reserved
  40  *                      (rather than bad) block in the stored bbt
  41  * @param pattern       pattern to identify bad block table or factory marked
  42  *                      good / bad blocks, can be NULL, if len = 0
  43  *
  44  * Descriptor for the bad block table marker and the descriptor for the
  45  * pattern which identifies good and bad blocks. The assumption is made
  46  * that the pattern and the version count are always located in the oob area
  47  * of the first block.
  48  */
  49 struct nand_bbt_descr {
  50         int options;
  51         int pages[NAND_MAX_CHIPS];
  52         int offs;
  53         int veroffs;
  54         uint8_t version[NAND_MAX_CHIPS];
  55         int len;
  56         int maxblocks;
  57         int reserved_block_code;
  58         uint8_t *pattern;
  59 };
  60
  61 /* Options for the bad block table descriptors */
  62
  63 /* The number of bits used per block in the bbt on the device */
  64 #define NAND_BBT_NRBITS_MSK     0x0000000F
  65 #define NAND_BBT_1BIT           0x00000001
  66 #define NAND_BBT_2BIT           0x00000002
  67 #define NAND_BBT_4BIT           0x00000004
  68 #define NAND_BBT_8BIT           0x00000008
  69 /* The bad block table is in the last good block of the device */
  70 #define NAND_BBT_LASTBLOCK      0x00000010
  71 /* The bbt is at the given page, else we must scan for the bbt */
  72 #define NAND_BBT_ABSPAGE        0x00000020
  73 /* The bbt is at the given page, else we must scan for the bbt */
  74 #define NAND_BBT_SEARCH         0x00000040
  75 /* bbt is stored per chip on multichip devices */
  76 #define NAND_BBT_PERCHIP        0x00000080
  77 /* bbt has a version counter at offset veroffs */
  78 #define NAND_BBT_VERSION        0x00000100
  79 /* Create a bbt if none axists */
  80 #define NAND_BBT_CREATE         0x00000200
  81 /* Search good / bad pattern through all pages of a block */
  82 #define NAND_BBT_SCANALLPAGES   0x00000400
  83 /* Scan block empty during good / bad block scan */
  84 #define NAND_BBT_SCANEMPTY      0x00000800
  85 /* Write bbt if neccecary */
  86 #define NAND_BBT_WRITE          0x00001000
  87 /* Read and write back block contents when writing bbt */
  88 #define NAND_BBT_SAVECONTENT    0x00002000
  89 /* Search good / bad pattern on the first and the second page */
  90 #define NAND_BBT_SCAN2NDPAGE    0x00004000
  91
  92 /* The maximum number of blocks to scan for a bbt */
  93 #define NAND_BBT_SCAN_MAXBLOCKS 4
  94
  95 /*
  96  * Constants for oob configuration
  97  */
  98 #define ONENAND_BADBLOCK_POS    0
  99
 100 /*
 101  * Bad block scanning errors
 102  */
 103 #define ONENAND_BBT_READ_ERROR          1
 104 #define ONENAND_BBT_READ_ECC_ERROR      2
 105 #define ONENAND_BBT_READ_FATAL_ERROR    4
 106
 107 /**
 108  * struct bbt_info - [GENERIC] Bad Block Table data structure
 109  * @param bbt_erase_shift       [INTERN] number of address bits in a bbt entry
 110  * @param badblockpos           [INTERN] position of the bad block marker in the oob area
 111  * @param bbt                   [INTERN] bad block table pointer
 112  * @param badblock_pattern      [REPLACEABLE] bad block scan pattern used for initial bad block scan
 113  * @param priv                  [OPTIONAL] pointer to private bbm date
 114  */
 115 struct bbm_info {
 116         int bbt_erase_shift;
 117         int badblockpos;
 118         int options;
 119
 120         uint8_t *bbt;
 121
 122         int (*isbad_bbt) (struct mtd_info * mtd, loff_t ofs, int allowbbt);
 123
 124         /* TODO Add more NAND specific fileds */
 125         struct nand_bbt_descr *badblock_pattern;
 126
 127         void *priv;
 128 };
 129
 130 /* OneNAND BBT interface */
 131 extern int onenand_scan_bbt (struct mtd_info *mtd, struct nand_bbt_descr *bd);
 132 extern int onenand_default_bbt (struct mtd_info *mtd);
 133
 134 #endif                          /* __LINUX_MTD_BBM_H */