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 <linux/ioctl.h>
  25 #include <linux/types.h>
  26 #include <mtd/ubi-user.h>
  27
  28 /*
  29  * enum ubi_open_mode - UBI volume open mode constants.
  30  *
  31  * UBI_READONLY: read-only mode
  32  * UBI_READWRITE: read-write mode
  33  * UBI_EXCLUSIVE: exclusive mode
  34  */
  35 enum {
  36         UBI_READONLY = 1,
  37         UBI_READWRITE,
  38         UBI_EXCLUSIVE
  39 };
  40
  41 /**
  42  * struct ubi_volume_info - UBI volume description data structure.
  43  * @vol_id: volume ID
  44  * @ubi_num: UBI device number this volume belongs to
  45  * @size: how many physical eraseblocks are reserved for this volume
  46  * @used_bytes: how many bytes of data this volume contains
  47  * @used_ebs: how many physical eraseblocks of this volume actually contain any
  48  *            data
  49  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
  50  * @corrupted: non-zero if the volume is corrupted (static volumes only)
  51  * @upd_marker: non-zero if the volume has update marker set
  52  * @alignment: volume alignment
  53  * @usable_leb_size: how many bytes are available in logical eraseblocks of
  54  *                   this volume
  55  * @name_len: volume name length
  56  * @name: volume name
  57  * @cdev: UBI volume character device major and minor numbers
  58  *
  59  * The @corrupted flag is only relevant to static volumes and is always zero
  60  * for dynamic ones. This is because UBI does not care about dynamic volume
  61  * data protection and only cares about protecting static volume data.
  62  *
  63  * The @upd_marker flag is set if the volume update operation was interrupted.
  64  * Before touching the volume data during the update operation, UBI first sets
  65  * the update marker flag for this volume. If the volume update operation was
  66  * further interrupted, the update marker indicates this. If the update marker
  67  * is set, the contents of the volume is certainly damaged and a new volume
  68  * update operation has to be started.
  69  *
  70  * To put it differently, @corrupted and @upd_marker fields have different
  71  * semantics:
  72  *     o the @corrupted flag means that this static volume is corrupted for some
  73  *       reasons, but not because an interrupted volume update
  74  *     o the @upd_marker field means that the volume is damaged because of an
  75  *       interrupted update operation.
  76  *
  77  * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
  78  *
  79  * The @used_bytes and @used_ebs fields are only really needed for static
  80  * volumes and contain the number of bytes stored in this static volume and how
  81  * many eraseblock this data occupies. In case of dynamic volumes, the
  82  * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
  83  * field is equivalent to @size.
  84  *
  85  * In general, logical eraseblock size is a property of the UBI device, not
  86  * of the UBI volume. Indeed, the logical eraseblock size depends on the
  87  * physical eraseblock size and on how much bytes UBI headers consume. But
  88  * because of the volume alignment (@alignment), the usable size of logical
  89  * eraseblocks if a volume may be less. The following equation is true:
  90  *      @usable_leb_size = LEB size - (LEB size mod @alignment),
  91  * where LEB size is the logical eraseblock size defined by the UBI device.
  92  *
  93  * The alignment is multiple to the minimal flash input/output unit size or %1
  94  * if all the available space is used.
  95  *
  96  * To put this differently, alignment may be considered is a way to change
  97  * volume logical eraseblock sizes.
  98  */
  99 struct ubi_volume_info {
 100         int ubi_num;
 101         int vol_id;
 102         int size;
 103         long long used_bytes;
 104         int used_ebs;
 105         int vol_type;
 106         int corrupted;
 107         int upd_marker;
 108         int alignment;
 109         int usable_leb_size;
 110         int name_len;
 111         const char *name;
 112         dev_t cdev;
 113 };
 114
 115 /**
 116  * struct ubi_device_info - UBI device description data structure.
 117  * @ubi_num: ubi device number
 118  * @leb_size: logical eraseblock size on this UBI device
 119  * @leb_start: starting offset of logical eraseblocks within physical
 120  *             eraseblocks
 121  * @min_io_size: minimal I/O unit size
 122  * @max_write_size: maximum amount of bytes the underlying flash can write at a
 123  *                  time (MTD write buffer size)
 124  * @ro_mode: if this device is in read-only mode
 125  * @cdev: UBI character device major and minor numbers
 126  *
 127  * Note, @leb_size is the logical eraseblock size offered by the UBI device.
 128  * Volumes of this UBI device may have smaller logical eraseblock size if their
 129  * alignment is not equivalent to %1.
 130  *
 131  * The @max_write_size field describes flash write maximum write unit. For
 132  * example, NOR flash allows for changing individual bytes, so @min_io_size is
 133  * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
 134  * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
 135  * writing large chunks of data, they write 64-bytes at a time. Obviously, this
 136  * improves write throughput.
 137  *
 138  * Also, the MTD device may have N interleaved (striped) flash chips
 139  * underneath, in which case @min_io_size can be physical min. I/O size of
 140  * single flash chip, while @max_write_size can be N * @min_io_size.
 141  *
 142  * The @max_write_size field is always greater or equivalent to @min_io_size.
 143  * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
 144  * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
 145  * page size.
 146  */
 147 struct ubi_device_info {
 148         int ubi_num;
 149         int leb_size;
 150         int leb_start;
 151         int min_io_size;
 152         int max_write_size;
 153         int ro_mode;
 154         dev_t cdev;
 155 };
 156
 157 /*
 158  * Volume notification types.
 159  * @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
 160  *                    volume was created)
 161  * @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
 162  *                      or a volume was removed)
 163  * @UBI_VOLUME_RESIZED: a volume has been re-sized
 164  * @UBI_VOLUME_RENAMED: a volume has been re-named
 165  * @UBI_VOLUME_UPDATED: data has been written to a volume
 166  *
 167  * These constants define which type of event has happened when a volume
 168  * notification function is invoked.
 169  */
 170 enum {
 171         UBI_VOLUME_ADDED,
 172         UBI_VOLUME_REMOVED,
 173         UBI_VOLUME_RESIZED,
 174         UBI_VOLUME_RENAMED,
 175         UBI_VOLUME_UPDATED,
 176 };
 177
 178 /*
 179  * struct ubi_notification - UBI notification description structure.
 180  * @di: UBI device description object
 181  * @vi: UBI volume description object
 182  *
 183  * UBI notifiers are called with a pointer to an object of this type. The
 184  * object describes the notification. Namely, it provides a description of the
 185  * UBI device and UBI volume the notification informs about.
 186  */
 187 struct ubi_notification {
 188         struct ubi_device_info di;
 189         struct ubi_volume_info vi;
 190 };
 191
 192 /* UBI descriptor given to users when they open UBI volumes */
 193 struct ubi_volume_desc;
 194
 195 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
 196 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 197                          struct ubi_volume_info *vi);
 198 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
 199 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 200                                            int mode);
 201 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
 202
 203 int ubi_register_volume_notifier(struct notifier_block *nb,
 204                                  int ignore_existing);
 205 int ubi_unregister_volume_notifier(struct notifier_block *nb);
 206
 207 void ubi_close_volume(struct ubi_volume_desc *desc);
 208 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 209                  int len, int check);
 210 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 211                   int offset, int len, int dtype);
 212 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 213                    int len, int dtype);
 214 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
 215 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
 216 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum, int dtype);
 217 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
 218 int ubi_sync(int ubi_num);
 219
 220 /*
 221  * This function is the same as the 'ubi_leb_read()' function, but it does not
 222  * provide the checking capability.
 223  */
 224 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
 225                            int offset, int len)
 226 {
 227         return ubi_leb_read(desc, lnum, buf, offset, len, 0);
 228 }
 229
 230 /*
 231  * This function is the same as the 'ubi_leb_write()' functions, but it does
 232  * not have the data type argument.
 233  */
 234 static inline int ubi_write(struct ubi_volume_desc *desc, int lnum,
 235                             const void *buf, int offset, int len)
 236 {
 237         return ubi_leb_write(desc, lnum, buf, offset, len, UBI_UNKNOWN);
 238 }
 239
 240 /*
 241  * This function is the same as the 'ubi_leb_change()' functions, but it does
 242  * not have the data type argument.
 243  */
 244 static inline int ubi_change(struct ubi_volume_desc *desc, int lnum,
 245                                     const void *buf, int len)
 246 {
 247         return ubi_leb_change(desc, lnum, buf, len, UBI_UNKNOWN);
 248 }
 249
 250 #endif /* !__LINUX_UBI_H__ */