linux/include/linux/mtd/bbm.h
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   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 © 2005 Samsung Electronics
   8 *  Kyungmin Park <kyungmin.park@samsung.com>
   9 *
  10 *  Copyright © 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 as published by
  15 * the Free Software Foundation; either version 2 of the License, or
  16 * (at your option) any later version.
  17 *
  18 * This program is distributed in the hope that it will be useful,
  19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 * GNU General Public License for more details.
  22 *
  23 * You should have received a copy of the GNU General Public License
  24 * along with this program; if not, write to the Free Software
  25 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  26 *
  27 */
  28#ifndef __LINUX_MTD_BBM_H
  29#define __LINUX_MTD_BBM_H
  30
  31/* The maximum number of NAND chips in an array */
  32#define NAND_MAX_CHIPS          8
  33
  34/**
  35 * struct nand_bbt_descr - bad block table descriptor
  36 * @options:    options for this descriptor
  37 * @pages:      the page(s) where we find the bbt, used with option BBT_ABSPAGE
  38 *              when bbt is searched, then we store the found bbts pages here.
  39 *              Its an array and supports up to 8 chips now
  40 * @offs:       offset of the pattern in the oob area of the page
  41 * @veroffs:    offset of the bbt version counter in the oob are of the page
  42 * @version:    version read from the bbt page during scan
  43 * @len:        length of the pattern, if 0 no pattern check is performed
  44 * @maxblocks:  maximum number of blocks to search for a bbt. This number of
  45 *              blocks is reserved at the end of the device where the tables are
  46 *              written.
  47 * @reserved_block_code: if non-0, this pattern denotes a reserved (rather than
  48 *              bad) block in the stored bbt
  49 * @pattern:    pattern to identify bad block table or factory marked good /
  50 *              bad blocks, can be NULL, if len = 0
  51 *
  52 * Descriptor for the bad block table marker and the descriptor for the
  53 * pattern which identifies good and bad blocks. The assumption is made
  54 * that the pattern and the version count are always located in the oob area
  55 * of the first block.
  56 */
  57struct nand_bbt_descr {
  58        int options;
  59        int pages[NAND_MAX_CHIPS];
  60        int offs;
  61        int veroffs;
  62        uint8_t version[NAND_MAX_CHIPS];
  63        int len;
  64        int maxblocks;
  65        int reserved_block_code;
  66        uint8_t *pattern;
  67};
  68
  69/* Options for the bad block table descriptors */
  70
  71/* The number of bits used per block in the bbt on the device */
  72#define NAND_BBT_NRBITS_MSK     0x0000000F
  73#define NAND_BBT_1BIT           0x00000001
  74#define NAND_BBT_2BIT           0x00000002
  75#define NAND_BBT_4BIT           0x00000004
  76#define NAND_BBT_8BIT           0x00000008
  77/* The bad block table is in the last good block of the device */
  78#define NAND_BBT_LASTBLOCK      0x00000010
  79/* The bbt is at the given page, else we must scan for the bbt */
  80#define NAND_BBT_ABSPAGE        0x00000020
  81/* bbt is stored per chip on multichip devices */
  82#define NAND_BBT_PERCHIP        0x00000080
  83/* bbt has a version counter at offset veroffs */
  84#define NAND_BBT_VERSION        0x00000100
  85/* Create a bbt if none exists */
  86#define NAND_BBT_CREATE         0x00000200
  87/*
  88 * Create an empty BBT with no vendor information. Vendor's information may be
  89 * unavailable, for example, if the NAND controller has a different data and OOB
  90 * layout or if this information is already purged. Must be used in conjunction
  91 * with NAND_BBT_CREATE.
  92 */
  93#define NAND_BBT_CREATE_EMPTY   0x00000400
  94/* Write bbt if neccecary */
  95#define NAND_BBT_WRITE          0x00002000
  96/* Read and write back block contents when writing bbt */
  97#define NAND_BBT_SAVECONTENT    0x00004000
  98/* Search good / bad pattern on the first and the second page */
  99#define NAND_BBT_SCAN2NDPAGE    0x00008000
 100/* Search good / bad pattern on the last page of the eraseblock */
 101#define NAND_BBT_SCANLASTPAGE   0x00010000
 102/*
 103 * Use a flash based bad block table. By default, OOB identifier is saved in
 104 * OOB area. This option is passed to the default bad block table function.
 105 */
 106#define NAND_BBT_USE_FLASH      0x00020000
 107/*
 108 * Do not store flash based bad block table marker in the OOB area; store it
 109 * in-band.
 110 */
 111#define NAND_BBT_NO_OOB         0x00040000
 112/*
 113 * Do not write new bad block markers to OOB; useful, e.g., when ECC covers
 114 * entire spare area. Must be used with NAND_BBT_USE_FLASH.
 115 */
 116#define NAND_BBT_NO_OOB_BBM     0x00080000
 117
 118/*
 119 * Flag set by nand_create_default_bbt_descr(), marking that the nand_bbt_descr
 120 * was allocated dynamicaly and must be freed in nand_release(). Has no meaning
 121 * in nand_chip.bbt_options.
 122 */
 123#define NAND_BBT_DYNAMICSTRUCT  0x80000000
 124
 125/* The maximum number of blocks to scan for a bbt */
 126#define NAND_BBT_SCAN_MAXBLOCKS 4
 127
 128/*
 129 * Constants for oob configuration
 130 */
 131#define NAND_SMALL_BADBLOCK_POS         5
 132#define NAND_LARGE_BADBLOCK_POS         0
 133#define ONENAND_BADBLOCK_POS            0
 134
 135/*
 136 * Bad block scanning errors
 137 */
 138#define ONENAND_BBT_READ_ERROR          1
 139#define ONENAND_BBT_READ_ECC_ERROR      2
 140#define ONENAND_BBT_READ_FATAL_ERROR    4
 141
 142/**
 143 * struct bbm_info - [GENERIC] Bad Block Table data structure
 144 * @bbt_erase_shift:    [INTERN] number of address bits in a bbt entry
 145 * @badblockpos:        [INTERN] position of the bad block marker in the oob area
 146 * @options:            options for this descriptor
 147 * @bbt:                [INTERN] bad block table pointer
 148 * @isbad_bbt:          function to determine if a block is bad
 149 * @badblock_pattern:   [REPLACEABLE] bad block scan pattern used for
 150 *                      initial bad block scan
 151 * @priv:               [OPTIONAL] pointer to private bbm date
 152 */
 153struct bbm_info {
 154        int bbt_erase_shift;
 155        int badblockpos;
 156        int options;
 157
 158        uint8_t *bbt;
 159
 160        int (*isbad_bbt)(struct mtd_info *mtd, loff_t ofs, int allowbbt);
 161
 162        /* TODO Add more NAND specific fileds */
 163        struct nand_bbt_descr *badblock_pattern;
 164
 165        void *priv;
 166};
 167
 168/* OneNAND BBT interface */
 169extern int onenand_default_bbt(struct mtd_info *mtd);
 170
 171#endif  /* __LINUX_MTD_BBM_H */
 172
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