include/linux/mtd/ubi.h

   1 /*
   2  * Copyright (c) International Business Machines Corp., 2006
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  *
   6  * Author: Artem Bityutskiy (Битюцкий Артём)
   7  */
   8
   9 #ifndef __LINUX_UBI_H__
  10 #define __LINUX_UBI_H__
  11
  12 #include <linux/types.h>
  13 #ifndef __UBOOT__
  14 #include <linux/ioctl.h>
  15 #include <linux/scatterlist.h>
  16 #include <mtd/ubi-user.h>
  17 #endif
  18
  19 /* All voumes/LEBs */
  20 #define UBI_ALL -1
  21
  22 /*
  23  * Maximum number of scatter gather list entries,
  24  * we use only 64 to have a lower memory foot print.
  25  */
  26 #define UBI_MAX_SG_COUNT 64
  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  * UBI_METAONLY: modify only the volume meta-data,
  35  *  i.e. the data stored in the volume table, but not in any of volume LEBs.
  36  */
  37 enum {
  38         UBI_READONLY = 1,
  39         UBI_READWRITE,
  40         UBI_EXCLUSIVE,
  41         UBI_METAONLY
  42 };
  43
  44 /**
  45  * struct ubi_volume_info - UBI volume description data structure.
  46  * @vol_id: volume ID
  47  * @ubi_num: UBI device number this volume belongs to
  48  * @size: how many physical eraseblocks are reserved for this volume
  49  * @used_bytes: how many bytes of data this volume contains
  50  * @used_ebs: how many physical eraseblocks of this volume actually contain any
  51  *            data
  52  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
  53  * @corrupted: non-zero if the volume is corrupted (static volumes only)
  54  * @upd_marker: non-zero if the volume has update marker set
  55  * @alignment: volume alignment
  56  * @usable_leb_size: how many bytes are available in logical eraseblocks of
  57  *                   this volume
  58  * @name_len: volume name length
  59  * @name: volume name
  60  * @cdev: UBI volume character device major and minor numbers
  61  *
  62  * The @corrupted flag is only relevant to static volumes and is always zero
  63  * for dynamic ones. This is because UBI does not care about dynamic volume
  64  * data protection and only cares about protecting static volume data.
  65  *
  66  * The @upd_marker flag is set if the volume update operation was interrupted.
  67  * Before touching the volume data during the update operation, UBI first sets
  68  * the update marker flag for this volume. If the volume update operation was
  69  * further interrupted, the update marker indicates this. If the update marker
  70  * is set, the contents of the volume is certainly damaged and a new volume
  71  * update operation has to be started.
  72  *
  73  * To put it differently, @corrupted and @upd_marker fields have different
  74  * semantics:
  75  *     o the @corrupted flag means that this static volume is corrupted for some
  76  *       reasons, but not because an interrupted volume update
  77  *     o the @upd_marker field means that the volume is damaged because of an
  78  *       interrupted update operation.
  79  *
  80  * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
  81  *
  82  * The @used_bytes and @used_ebs fields are only really needed for static
  83  * volumes and contain the number of bytes stored in this static volume and how
  84  * many eraseblock this data occupies. In case of dynamic volumes, the
  85  * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
  86  * field is equivalent to @size.
  87  *
  88  * In general, logical eraseblock size is a property of the UBI device, not
  89  * of the UBI volume. Indeed, the logical eraseblock size depends on the
  90  * physical eraseblock size and on how much bytes UBI headers consume. But
  91  * because of the volume alignment (@alignment), the usable size of logical
  92  * eraseblocks if a volume may be less. The following equation is true:
  93  *      @usable_leb_size = LEB size - (LEB size mod @alignment),
  94  * where LEB size is the logical eraseblock size defined by the UBI device.
  95  *
  96  * The alignment is multiple to the minimal flash input/output unit size or %1
  97  * if all the available space is used.
  98  *
  99  * To put this differently, alignment may be considered is a way to change
 100  * volume logical eraseblock sizes.
 101  */
 102 struct ubi_volume_info {
 103         int ubi_num;
 104         int vol_id;
 105         int size;
 106         long long used_bytes;
 107         int used_ebs;
 108         int vol_type;
 109         int corrupted;
 110         int upd_marker;
 111         int alignment;
 112         int usable_leb_size;
 113         int name_len;
 114         const char *name;
 115         dev_t cdev;
 116 };
 117
 118 /**
 119  * struct ubi_sgl - UBI scatter gather list data structure.
 120  * @list_pos: current position in @sg[]
 121  * @page_pos: current position in @sg[@list_pos]
 122  * @sg: the scatter gather list itself
 123  *
 124  * ubi_sgl is a wrapper around a scatter list which keeps track of the
 125  * current position in the list and the current list item such that
 126  * it can be used across multiple ubi_leb_read_sg() calls.
 127  */
 128 struct ubi_sgl {
 129         int list_pos;
 130         int page_pos;
 131 #ifndef __UBOOT__
 132         struct scatterlist sg[UBI_MAX_SG_COUNT];
 133 #endif
 134 };
 135
 136 /**
 137  * ubi_sgl_init - initialize an UBI scatter gather list data structure.
 138  * @usgl: the UBI scatter gather struct itself
 139  *
 140  * Please note that you still have to use sg_init_table() or any adequate
 141  * function to initialize the unterlaying struct scatterlist.
 142  */
 143 static inline void ubi_sgl_init(struct ubi_sgl *usgl)
 144 {
 145         usgl->list_pos = 0;
 146         usgl->page_pos = 0;
 147 }
 148
 149 /**
 150  * struct ubi_device_info - UBI device description data structure.
 151  * @ubi_num: ubi device number
 152  * @leb_size: logical eraseblock size on this UBI device
 153  * @leb_start: starting offset of logical eraseblocks within physical
 154  *             eraseblocks
 155  * @min_io_size: minimal I/O unit size
 156  * @max_write_size: maximum amount of bytes the underlying flash can write at a
 157  *                  time (MTD write buffer size)
 158  * @ro_mode: if this device is in read-only mode
 159  * @cdev: UBI character device major and minor numbers
 160  *
 161  * Note, @leb_size is the logical eraseblock size offered by the UBI device.
 162  * Volumes of this UBI device may have smaller logical eraseblock size if their
 163  * alignment is not equivalent to %1.
 164  *
 165  * The @max_write_size field describes flash write maximum write unit. For
 166  * example, NOR flash allows for changing individual bytes, so @min_io_size is
 167  * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
 168  * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
 169  * writing large chunks of data, they write 64-bytes at a time. Obviously, this
 170  * improves write throughput.
 171  *
 172  * Also, the MTD device may have N interleaved (striped) flash chips
 173  * underneath, in which case @min_io_size can be physical min. I/O size of
 174  * single flash chip, while @max_write_size can be N * @min_io_size.
 175  *
 176  * The @max_write_size field is always greater or equivalent to @min_io_size.
 177  * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
 178  * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
 179  * page size.
 180  */
 181 struct ubi_device_info {
 182         int ubi_num;
 183         int leb_size;
 184         int leb_start;
 185         int min_io_size;
 186         int max_write_size;
 187         int ro_mode;
 188 #ifndef __UBOOT__
 189         dev_t cdev;
 190 #endif
 191 };
 192
 193 /*
 194  * Volume notification types.
 195  * @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
 196  *                    volume was created)
 197  * @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
 198  *                      or a volume was removed)
 199  * @UBI_VOLUME_RESIZED: a volume has been re-sized
 200  * @UBI_VOLUME_RENAMED: a volume has been re-named
 201  * @UBI_VOLUME_UPDATED: data has been written to a volume
 202  *
 203  * These constants define which type of event has happened when a volume
 204  * notification function is invoked.
 205  */
 206 enum {
 207         UBI_VOLUME_ADDED,
 208         UBI_VOLUME_REMOVED,
 209         UBI_VOLUME_RESIZED,
 210         UBI_VOLUME_RENAMED,
 211         UBI_VOLUME_UPDATED,
 212 };
 213
 214 /*
 215  * struct ubi_notification - UBI notification description structure.
 216  * @di: UBI device description object
 217  * @vi: UBI volume description object
 218  *
 219  * UBI notifiers are called with a pointer to an object of this type. The
 220  * object describes the notification. Namely, it provides a description of the
 221  * UBI device and UBI volume the notification informs about.
 222  */
 223 struct ubi_notification {
 224         struct ubi_device_info di;
 225         struct ubi_volume_info vi;
 226 };
 227
 228 /* UBI descriptor given to users when they open UBI volumes */
 229 struct ubi_volume_desc;
 230
 231 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
 232 void ubi_get_volume_info(struct ubi_volume_desc *desc,
 233                          struct ubi_volume_info *vi);
 234 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
 235 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
 236                                            int mode);
 237 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
 238
 239 #ifndef __UBOOT__
 240 typedef int (*notifier_fn_t)(void *nb,
 241                         unsigned long action, void *data);
 242
 243 struct notifier_block {
 244         notifier_fn_t notifier_call;
 245         struct notifier_block *next;
 246         void *next;
 247         int priority;
 248 };
 249
 250 int ubi_register_volume_notifier(struct notifier_block *nb,
 251                                  int ignore_existing);
 252 int ubi_unregister_volume_notifier(struct notifier_block *nb);
 253 #endif
 254
 255 void ubi_close_volume(struct ubi_volume_desc *desc);
 256 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
 257                  int len, int check);
 258 int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
 259                    int offset, int len, int check);
 260 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
 261                   int offset, int len);
 262 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
 263                    int len);
 264 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
 265 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
 266 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
 267 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
 268 int ubi_sync(int ubi_num);
 269 int ubi_flush(int ubi_num, int vol_id, int lnum);
 270
 271 /*
 272  * This function is the same as the 'ubi_leb_read()' function, but it does not
 273  * provide the checking capability.
 274  */
 275 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
 276                            int offset, int len)
 277 {
 278         return ubi_leb_read(desc, lnum, buf, offset, len, 0);
 279 }
 280
 281 /*
 282  * This function is the same as the 'ubi_leb_read_sg()' function, but it does
 283  * not provide the checking capability.
 284  */
 285 static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
 286                               struct ubi_sgl *sgl, int offset, int len)
 287 {
 288         return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
 289 }
 290 #endif /* !__LINUX_UBI_H__ */