linux/include/mtd/ubi-user.h
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   1/*
   2 * Copyright © 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 __UBI_USER_H__
  22#define __UBI_USER_H__
  23
  24#include <linux/types.h>
  25
  26/*
  27 * UBI device creation (the same as MTD device attachment)
  28 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  29 *
  30 * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
  31 * control device. The caller has to properly fill and pass
  32 * &struct ubi_attach_req object - UBI will attach the MTD device specified in
  33 * the request and return the newly created UBI device number as the ioctl
  34 * return value.
  35 *
  36 * UBI device deletion (the same as MTD device detachment)
  37 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  38 *
  39 * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
  40 * control device.
  41 *
  42 * UBI volume creation
  43 * ~~~~~~~~~~~~~~~~~~~
  44 *
  45 * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
  46 * device. A &struct ubi_mkvol_req object has to be properly filled and a
  47 * pointer to it has to be passed to the ioctl.
  48 *
  49 * UBI volume deletion
  50 * ~~~~~~~~~~~~~~~~~~~
  51 *
  52 * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
  53 * device should be used. A pointer to the 32-bit volume ID hast to be passed
  54 * to the ioctl.
  55 *
  56 * UBI volume re-size
  57 * ~~~~~~~~~~~~~~~~~~
  58 *
  59 * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
  60 * device should be used. A &struct ubi_rsvol_req object has to be properly
  61 * filled and a pointer to it has to be passed to the ioctl.
  62 *
  63 * UBI volumes re-name
  64 * ~~~~~~~~~~~~~~~~~~~
  65 *
  66 * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
  67 * of the UBI character device should be used. A &struct ubi_rnvol_req object
  68 * has to be properly filled and a pointer to it has to be passed to the ioctl.
  69 *
  70 * UBI volume update
  71 * ~~~~~~~~~~~~~~~~~
  72 *
  73 * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
  74 * corresponding UBI volume character device. A pointer to a 64-bit update
  75 * size should be passed to the ioctl. After this, UBI expects user to write
  76 * this number of bytes to the volume character device. The update is finished
  77 * when the claimed number of bytes is passed. So, the volume update sequence
  78 * is something like:
  79 *
  80 * fd = open("/dev/my_volume");
  81 * ioctl(fd, UBI_IOCVOLUP, &image_size);
  82 * write(fd, buf, image_size);
  83 * close(fd);
  84 *
  85 * Logical eraseblock erase
  86 * ~~~~~~~~~~~~~~~~~~~~~~~~
  87 *
  88 * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
  89 * corresponding UBI volume character device should be used. This command
  90 * unmaps the requested logical eraseblock, makes sure the corresponding
  91 * physical eraseblock is successfully erased, and returns.
  92 *
  93 * Atomic logical eraseblock change
  94 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  95 *
  96 * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
  97 * ioctl command of the corresponding UBI volume character device. A pointer to
  98 * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
  99 * user is expected to write the requested amount of bytes (similarly to what
 100 * should be done in case of the "volume update" ioctl).
 101 *
 102 * Logical eraseblock map
 103 * ~~~~~~~~~~~~~~~~~~~~~
 104 *
 105 * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
 106 * ioctl command should be used. A pointer to a &struct ubi_map_req object is
 107 * expected to be passed. The ioctl maps the requested logical eraseblock to
 108 * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
 109 * be mapped. If the logical eraseblock specified in the request is already
 110 * mapped to a physical eraseblock, the ioctl fails and returns error.
 111 *
 112 * Logical eraseblock unmap
 113 * ~~~~~~~~~~~~~~~~~~~~~~~~
 114 *
 115 * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
 116 * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
 117 * schedules corresponding physical eraseblock for erasure, and returns. Unlike
 118 * the "LEB erase" command, it does not wait for the physical eraseblock being
 119 * erased. Note, the side effect of this is that if an unclean reboot happens
 120 * after the unmap ioctl returns, you may find the LEB mapped again to the same
 121 * physical eraseblock after the UBI is run again.
 122 *
 123 * Check if logical eraseblock is mapped
 124 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 125 *
 126 * To check if a logical eraseblock is mapped to a physical eraseblock, the
 127 * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
 128 * not mapped, and %1 if it is mapped.
 129 *
 130 * Set an UBI volume property
 131 * ~~~~~~~~~~~~~~~~~~~~~~~~~
 132 *
 133 * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
 134 * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
 135 * passed. The object describes which property should be set, and to which value
 136 * it should be set.
 137 */
 138
 139/*
 140 * When a new UBI volume or UBI device is created, users may either specify the
 141 * volume/device number they want to create or to let UBI automatically assign
 142 * the number using these constants.
 143 */
 144#define UBI_VOL_NUM_AUTO (-1)
 145#define UBI_DEV_NUM_AUTO (-1)
 146
 147/* Maximum volume name length */
 148#define UBI_MAX_VOLUME_NAME 127
 149
 150/* ioctl commands of UBI character devices */
 151
 152#define UBI_IOC_MAGIC 'o'
 153
 154/* Create an UBI volume */
 155#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
 156/* Remove an UBI volume */
 157#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
 158/* Re-size an UBI volume */
 159#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
 160/* Re-name volumes */
 161#define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
 162
 163/* ioctl commands of the UBI control character device */
 164
 165#define UBI_CTRL_IOC_MAGIC 'o'
 166
 167/* Attach an MTD device */
 168#define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
 169/* Detach an MTD device */
 170#define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
 171
 172/* ioctl commands of UBI volume character devices */
 173
 174#define UBI_VOL_IOC_MAGIC 'O'
 175
 176/* Start UBI volume update */
 177#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
 178/* LEB erasure command, used for debugging, disabled by default */
 179#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
 180/* Atomic LEB change command */
 181#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
 182/* Map LEB command */
 183#define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
 184/* Unmap LEB command */
 185#define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
 186/* Check if LEB is mapped command */
 187#define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
 188/* Set an UBI volume property */
 189#define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 190                               struct ubi_set_vol_prop_req)
 191
 192/* Maximum MTD device name length supported by UBI */
 193#define MAX_UBI_MTD_NAME_LEN 127
 194
 195/* Maximum amount of UBI volumes that can be re-named at one go */
 196#define UBI_MAX_RNVOL 32
 197
 198/*
 199 * UBI volume type constants.
 200 *
 201 * @UBI_DYNAMIC_VOLUME: dynamic volume
 202 * @UBI_STATIC_VOLUME:  static volume
 203 */
 204enum {
 205        UBI_DYNAMIC_VOLUME = 3,
 206        UBI_STATIC_VOLUME  = 4,
 207};
 208
 209/*
 210 * UBI set volume property ioctl constants.
 211 *
 212 * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
 213 *                             user to directly write and erase individual
 214 *                             eraseblocks on dynamic volumes
 215 */
 216enum {
 217        UBI_VOL_PROP_DIRECT_WRITE = 1,
 218};
 219
 220/**
 221 * struct ubi_attach_req - attach MTD device request.
 222 * @ubi_num: UBI device number to create
 223 * @mtd_num: MTD device number to attach
 224 * @vid_hdr_offset: VID header offset (use defaults if %0)
 225 * @padding: reserved for future, not used, has to be zeroed
 226 *
 227 * This data structure is used to specify MTD device UBI has to attach and the
 228 * parameters it has to use. The number which should be assigned to the new UBI
 229 * device is passed in @ubi_num. UBI may automatically assign the number if
 230 * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 231 * @ubi_num.
 232 *
 233 * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 234 * offset of the VID header within physical eraseblocks. The default offset is
 235 * the next min. I/O unit after the EC header. For example, it will be offset
 236 * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 237 * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 238 *
 239 * But in rare cases, if this optimizes things, the VID header may be placed to
 240 * a different offset. For example, the boot-loader might do things faster if
 241 * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
 242 * As the boot-loader would not normally need to read EC headers (unless it
 243 * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
 244 * example, but it real-life example. So, in this example, @vid_hdr_offer would
 245 * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 246 * aligned, which is OK, as UBI is clever enough to realize this is 4th
 247 * sub-page of the first page and add needed padding.
 248 */
 249struct ubi_attach_req {
 250        __s32 ubi_num;
 251        __s32 mtd_num;
 252        __s32 vid_hdr_offset;
 253        __s8 padding[12];
 254};
 255
 256/**
 257 * struct ubi_mkvol_req - volume description data structure used in
 258 *                        volume creation requests.
 259 * @vol_id: volume number
 260 * @alignment: volume alignment
 261 * @bytes: volume size in bytes
 262 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 263 * @padding1: reserved for future, not used, has to be zeroed
 264 * @name_len: volume name length
 265 * @padding2: reserved for future, not used, has to be zeroed
 266 * @name: volume name
 267 *
 268 * This structure is used by user-space programs when creating new volumes. The
 269 * @used_bytes field is only necessary when creating static volumes.
 270 *
 271 * The @alignment field specifies the required alignment of the volume logical
 272 * eraseblock. This means, that the size of logical eraseblocks will be aligned
 273 * to this number, i.e.,
 274 *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 275 *
 276 * To put it differently, the logical eraseblock of this volume may be slightly
 277 * shortened in order to make it properly aligned. The alignment has to be
 278 * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 279 * available space of logical eraseblocks.
 280 *
 281 * The @alignment field may be useful, for example, when one wants to maintain
 282 * a block device on top of an UBI volume. In this case, it is desirable to fit
 283 * an integer number of blocks in logical eraseblocks of this UBI volume. With
 284 * alignment it is possible to update this volume using plane UBI volume image
 285 * BLOBs, without caring about how to properly align them.
 286 */
 287struct ubi_mkvol_req {
 288        __s32 vol_id;
 289        __s32 alignment;
 290        __s64 bytes;
 291        __s8 vol_type;
 292        __s8 padding1;
 293        __s16 name_len;
 294        __s8 padding2[4];
 295        char name[UBI_MAX_VOLUME_NAME + 1];
 296} __packed;
 297
 298/**
 299 * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 300 * @vol_id: ID of the volume to re-size
 301 * @bytes: new size of the volume in bytes
 302 *
 303 * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 304 * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 305 * smaller than the number of bytes they bear. To arbitrarily shrink a static
 306 * volume, it must be wiped out first (by means of volume update operation with
 307 * zero number of bytes).
 308 */
 309struct ubi_rsvol_req {
 310        __s64 bytes;
 311        __s32 vol_id;
 312} __packed;
 313
 314/**
 315 * struct ubi_rnvol_req - volumes re-name request.
 316 * @count: count of volumes to re-name
 317 * @padding1:  reserved for future, not used, has to be zeroed
 318 * @vol_id: ID of the volume to re-name
 319 * @name_len: name length
 320 * @padding2:  reserved for future, not used, has to be zeroed
 321 * @name: new volume name
 322 *
 323 * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
 324 * re-name is specified in the @count field. The ID of the volumes to re-name
 325 * and the new names are specified in the @vol_id and @name fields.
 326 *
 327 * The UBI volume re-name operation is atomic, which means that should power cut
 328 * happen, the volumes will have either old name or new name. So the possible
 329 * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
 330 * A and B one may create temporary volumes %A1 and %B1 with the new contents,
 331 * then atomically re-name A1->A and B1->B, in which case old %A and %B will
 332 * be removed.
 333 *
 334 * If it is not desirable to remove old A and B, the re-name request has to
 335 * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
 336 * become A and B, and old A and B will become A1 and B1.
 337 *
 338 * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
 339 * and B1 become A and B, and old A and B become X and Y.
 340 *
 341 * In other words, in case of re-naming into an existing volume name, the
 342 * existing volume is removed, unless it is re-named as well at the same
 343 * re-name request.
 344 */
 345struct ubi_rnvol_req {
 346        __s32 count;
 347        __s8 padding1[12];
 348        struct {
 349                __s32 vol_id;
 350                __s16 name_len;
 351                __s8  padding2[2];
 352                char    name[UBI_MAX_VOLUME_NAME + 1];
 353        } ents[UBI_MAX_RNVOL];
 354} __packed;
 355
 356/**
 357 * struct ubi_leb_change_req - a data structure used in atomic LEB change
 358 *                             requests.
 359 * @lnum: logical eraseblock number to change
 360 * @bytes: how many bytes will be written to the logical eraseblock
 361 * @dtype: pass "3" for better compatibility with old kernels
 362 * @padding: reserved for future, not used, has to be zeroed
 363 *
 364 * The @dtype field used to inform UBI about what kind of data will be written
 365 * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
 366 * UBI tried to pick a PEB with lower erase counter for short term data and a
 367 * PEB with higher erase counter for long term data. But this was not really
 368 * used because users usually do not know this and could easily mislead UBI. We
 369 * removed this feature in May 2012. UBI currently just ignores the @dtype
 370 * field. But for better compatibility with older kernels it is recommended to
 371 * set @dtype to 3 (unknown).
 372 */
 373struct ubi_leb_change_req {
 374        __s32 lnum;
 375        __s32 bytes;
 376        __s8  dtype; /* obsolete, do not use! */
 377        __s8  padding[7];
 378} __packed;
 379
 380/**
 381 * struct ubi_map_req - a data structure used in map LEB requests.
 382 * @dtype: pass "3" for better compatibility with old kernels
 383 * @lnum: logical eraseblock number to unmap
 384 * @padding: reserved for future, not used, has to be zeroed
 385 */
 386struct ubi_map_req {
 387        __s32 lnum;
 388        __s8  dtype; /* obsolete, do not use! */
 389        __s8  padding[3];
 390} __packed;
 391
 392
 393/**
 394 * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
 395 *                               property.
 396 * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
 397 * @padding: reserved for future, not used, has to be zeroed
 398 * @value: value to set
 399 */
 400struct ubi_set_vol_prop_req {
 401        __u8  property;
 402        __u8  padding[7];
 403        __u64 value;
 404}  __packed;
 405
 406#endif /* __UBI_USER_H__ */
 407
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