include/linux/mtd/ubi.h

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  12  * the GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  17  *
  18  * Author: Artem Bityutskiy (Битюцкий Артём)
  19  */
  20
  21 #ifndef __LINUX_UBI_H__
  22 #define __LINUX_UBI_H__
  23
  24 #include <asm/ioctl.h>
  25 #include <linux/types.h>
  26 #include <mtd/ubi-user.h>
  27
  28 /*
  29  * UBI data type hint constants.
  30  *
  31  * UBI_LONGTERM: long-term data
  32  * UBI_SHORTTERM: short-term data
  33  * UBI_UNKNOWN: data persistence is unknown
  34  *
  35  * These constants are used when data is written to UBI volumes in order to
  36  * help the UBI wear-leveling unit to find more appropriate physical
  37  * eraseblocks.
  38  */
  39 enum {
  40         UBI_LONGTERM = 1,
  41         UBI_SHORTTERM,
  42         UBI_UNKNOWN
  43 };
  44
  45 /*
  46  * enum ubi_open_mode - UBI volume open mode constants.
  47  *
  48  * UBI_READONLY: read-only mode
  49  * UBI_READWRITE: read-write mode
  50  * UBI_EXCLUSIVE: exclusive mode
  51  */
  52 enum {
  53         UBI_READONLY = 1,
  54         UBI_READWRITE,
  55         UBI_EXCLUSIVE
  56 };
  57
  58 /**
  59  * struct ubi_volume_info - UBI volume description data structure.
  60  * @vol_id: volume ID
  61  * @ubi_num: UBI device number this volume belongs to
  62  * @size: how many physical eraseblocks are reserved for this volume
  63  * @used_bytes: how many bytes of data this volume contains
  64  * @used_ebs: how many physical eraseblocks of this volume actually contain any
  65  * data
  66  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
  67  * @corrupted: non-zero if the volume is corrupted (static volumes only)
  68  * @upd_marker: non-zero if the volume has update marker set
  69  * @alignment: volume alignment
  70  * @usable_leb_size: how many bytes are available in logical eraseblocks of
  71  * this volume
  72  * @name_len: volume name length
  73  * @name: volume name
  74  * @cdev: UBI volume character device major and minor numbers
  75  *
  76  * The @corrupted flag is only relevant to static volumes and is always zero
  77  * for dynamic ones. This is because UBI does not care about dynamic volume
  78  * data protection and only cares about protecting static volume data.
  79  *
  80  * The @upd_marker flag is set if the volume update operation was interrupted.
  81  * Before touching the volume data during the update operation, UBI first sets
  82  * the update marker flag for this volume. If the volume update operation was
  83  * further interrupted, the update marker indicates this. If the update marker
  84  * is set, the contents of the volume is certainly damaged and a new volume
  85  * update operation has to be started.
  86  *
  87  * To put it differently, @corrupted and @upd_marker fields have different
  88  * semantics:
  89  *     o the @corrupted flag means that this static volume is corrupted for some
  90  *       reasons, but not because an interrupted volume update
  91  *     o the @upd_marker field means that the volume is damaged because of an
  92  *       interrupted update operation.
  93  *
  94  * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
  95  *
  96  * The @used_bytes and @used_ebs fields are only really needed for static
  97  * volumes and contain the number of bytes stored in this static volume and how
  98  * many eraseblock this data occupies. In case of dynamic volumes, the
  99  * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
 100  * field is equivalent to @size.
 101  *
 102  * In general, logical eraseblock size is a property of the UBI device, not
 103  * of the UBI volume. Indeed, the logical eraseblock size depends on the
 104  * physical eraseblock size and on how much bytes UBI headers consume. But
 105  * because of the volume alignment (@alignment), the usable size of logical
 106  * eraseblocks if a volume may be less. The following equation is true:
 107  *      @usable_leb_size = LEB size - (LEB size mod @alignment),
 108  * where LEB size is the logical eraseblock size defined by the UBI device.
 109  *
 110  * The alignment is multiple to the minimal flash input/output unit size or %1
 111  * if all the available space is used.
 112  *
 113  * To put this differently, alignment may be considered is a way to change
 114  * volume logical eraseblock sizes.
 115  */
 116 struct ubi_volume_info {
 117         int ubi_num;
 118         int vol_id;
 119         int size;
 120         long long used_bytes;
 121         int used_ebs;
 122         int vol_type;
 123         int corrupted;
 124         int upd_marker;
 125         int alignment;
 126         int usable_leb_size;
 127         int name_len;
 128         const char *name;
 129         dev_t cdev;
 130 };
 131
 132 /**
 133  * struct ubi_device_info - UBI device description data structure.
 134  * @ubi_num: ubi device number
 135  * @leb_size: logical eraseblock size on this UBI device
 136  * @min_io_size: minimal I/O unit size
 137  * @ro_mode: if this device is in read-only mode
 138  * @cdev: UBI character device major and minor numbers
 139  *
 140  * Note, @leb_size is the logical eraseblock size offered by the UBI device.
 141  * Volumes of this UBI device may have smaller logical eraseblock size if their
 142  * alignment is not equivalent to %1.
 143  */
 144 struct ubi_device_info {
 145         int ubi_num;
 146         int leb_size;
 147         int min_io_size;
 148         int ro_mode;
 149         dev_t cdev;
 150 };
 151
 152 /* UBI descriptor given to users when they open UBI volumes */
 153 struct ubi_volume_desc;
 154
 155 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
 156 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 157                          struct ubi_volume_info *vi);
 158 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
 159 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 160                                            int mode);
 161 void ubi_close_volume(struct ubi_volume_desc *desc);
 162 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 163                  int len, int check);
 164 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 165                   int offset, int len, int dtype);
 166 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 167                    int len, int dtype);
 168 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
 169 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
 170 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
 171
 172 /*
 173  * This function is the same as the 'ubi_leb_read()' function, but it does not
 174  * provide the checking capability.
 175  */
 176 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
 177                            int offset, int len)
 178 {
 179         return ubi_leb_read(desc, lnum, buf, offset, len, 0);
 180 }
 181
 182 /*
 183  * This function is the same as the 'ubi_leb_write()' functions, but it does
 184  * not have the data type argument.
 185  */
 186 static inline int ubi_write(struct ubi_volume_desc *desc, int lnum,
 187                             const void *buf, int offset, int len)
 188 {
 189         return ubi_leb_write(desc, lnum, buf, offset, len, UBI_UNKNOWN);
 190 }
 191
 192 /*
 193  * This function is the same as the 'ubi_leb_change()' functions, but it does
 194  * not have the data type argument.
 195  */
 196 static inline int ubi_change(struct ubi_volume_desc *desc, int lnum,
 197                                     const void *buf, int len)
 198 {
 199         return ubi_leb_change(desc, lnum, buf, len, UBI_UNKNOWN);
 200 }
 201
 202 #endif /* !__LINUX_UBI_H__ */