include/uapi/mtd/ubi-user.h

   1 /* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
   2 /*
   3  * Copyright © International Business Machines Corp., 2006
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
  13  * the GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  18  *
  19  * Author: Artem Bityutskiy (Битюцкий Артём)
  20  */
  21
  22 #ifndef __UBI_USER_H__
  23 #define __UBI_USER_H__
  24
  25 #include <linux/types.h>
  26
  27 /*
  28  * UBI device creation (the same as MTD device attachment)
  29  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  30  *
  31  * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
  32  * control device. The caller has to properly fill and pass
  33  * &struct ubi_attach_req object - UBI will attach the MTD device specified in
  34  * the request and return the newly created UBI device number as the ioctl
  35  * return value.
  36  *
  37  * UBI device deletion (the same as MTD device detachment)
  38  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  39  *
  40  * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
  41  * control device.
  42  *
  43  * UBI volume creation
  44  * ~~~~~~~~~~~~~~~~~~~
  45  *
  46  * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
  47  * device. A &struct ubi_mkvol_req object has to be properly filled and a
  48  * pointer to it has to be passed to the ioctl.
  49  *
  50  * UBI volume deletion
  51  * ~~~~~~~~~~~~~~~~~~~
  52  *
  53  * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
  54  * device should be used. A pointer to the 32-bit volume ID hast to be passed
  55  * to the ioctl.
  56  *
  57  * UBI volume re-size
  58  * ~~~~~~~~~~~~~~~~~~
  59  *
  60  * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
  61  * device should be used. A &struct ubi_rsvol_req object has to be properly
  62  * filled and a pointer to it has to be passed to the ioctl.
  63  *
  64  * UBI volumes re-name
  65  * ~~~~~~~~~~~~~~~~~~~
  66  *
  67  * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
  68  * of the UBI character device should be used. A &struct ubi_rnvol_req object
  69  * has to be properly filled and a pointer to it has to be passed to the ioctl.
  70  *
  71  * UBI volume update
  72  * ~~~~~~~~~~~~~~~~~
  73  *
  74  * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
  75  * corresponding UBI volume character device. A pointer to a 64-bit update
  76  * size should be passed to the ioctl. After this, UBI expects user to write
  77  * this number of bytes to the volume character device. The update is finished
  78  * when the claimed number of bytes is passed. So, the volume update sequence
  79  * is something like:
  80  *
  81  * fd = open("/dev/my_volume");
  82  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  83  * write(fd, buf, image_size);
  84  * close(fd);
  85  *
  86  * Logical eraseblock erase
  87  * ~~~~~~~~~~~~~~~~~~~~~~~~
  88  *
  89  * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
  90  * corresponding UBI volume character device should be used. This command
  91  * unmaps the requested logical eraseblock, makes sure the corresponding
  92  * physical eraseblock is successfully erased, and returns.
  93  *
  94  * Atomic logical eraseblock change
  95  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  96  *
  97  * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
  98  * ioctl command of the corresponding UBI volume character device. A pointer to
  99  * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
 100  * user is expected to write the requested amount of bytes (similarly to what
 101  * should be done in case of the "volume update" ioctl).
 102  *
 103  * Logical eraseblock map
 104  * ~~~~~~~~~~~~~~~~~~~~~
 105  *
 106  * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
 107  * ioctl command should be used. A pointer to a &struct ubi_map_req object is
 108  * expected to be passed. The ioctl maps the requested logical eraseblock to
 109  * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
 110  * be mapped. If the logical eraseblock specified in the request is already
 111  * mapped to a physical eraseblock, the ioctl fails and returns error.
 112  *
 113  * Logical eraseblock unmap
 114  * ~~~~~~~~~~~~~~~~~~~~~~~~
 115  *
 116  * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
 117  * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
 118  * schedules corresponding physical eraseblock for erasure, and returns. Unlike
 119  * the "LEB erase" command, it does not wait for the physical eraseblock being
 120  * erased. Note, the side effect of this is that if an unclean reboot happens
 121  * after the unmap ioctl returns, you may find the LEB mapped again to the same
 122  * physical eraseblock after the UBI is run again.
 123  *
 124  * Check if logical eraseblock is mapped
 125  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 126  *
 127  * To check if a logical eraseblock is mapped to a physical eraseblock, the
 128  * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
 129  * not mapped, and %1 if it is mapped.
 130  *
 131  * Set an UBI volume property
 132  * ~~~~~~~~~~~~~~~~~~~~~~~~~
 133  *
 134  * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
 135  * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
 136  * passed. The object describes which property should be set, and to which value
 137  * it should be set.
 138  *
 139  * Block devices on UBI volumes
 140  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 141  *
 142  * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
 143  * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
 144  * to be passed, which is not used and reserved for future usage.
 145  *
 146  * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
 147  * which takes no arguments.
 148  */
 149
 150 /*
 151  * When a new UBI volume or UBI device is created, users may either specify the
 152  * volume/device number they want to create or to let UBI automatically assign
 153  * the number using these constants.
 154  */
 155 #define UBI_VOL_NUM_AUTO (-1)
 156 #define UBI_DEV_NUM_AUTO (-1)
 157
 158 /* Maximum volume name length */
 159 #define UBI_MAX_VOLUME_NAME 127
 160
 161 /* ioctl commands of UBI character devices */
 162
 163 #define UBI_IOC_MAGIC 'o'
 164
 165 /* Create an UBI volume */
 166 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
 167 /* Remove an UBI volume */
 168 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
 169 /* Re-size an UBI volume */
 170 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
 171 /* Re-name volumes */
 172 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
 173
 174 /* ioctl commands of the UBI control character device */
 175
 176 #define UBI_CTRL_IOC_MAGIC 'o'
 177
 178 /* Attach an MTD device */
 179 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
 180 /* Detach an MTD device */
 181 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
 182
 183 /* ioctl commands of UBI volume character devices */
 184
 185 #define UBI_VOL_IOC_MAGIC 'O'
 186
 187 /* Start UBI volume update
 188  * Note: This actually takes a pointer (__s64*), but we can't change
 189  *       that without breaking the ABI on 32bit systems
 190  */
 191 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
 192 /* LEB erasure command, used for debugging, disabled by default */
 193 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
 194 /* Atomic LEB change command */
 195 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
 196 /* Map LEB command */
 197 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
 198 /* Unmap LEB command */
 199 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
 200 /* Check if LEB is mapped command */
 201 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
 202 /* Set an UBI volume property */
 203 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 204                                struct ubi_set_vol_prop_req)
 205 /* Create a R/O block device on top of an UBI volume */
 206 #define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
 207 /* Remove the R/O block device */
 208 #define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
 209
 210 /* Maximum MTD device name length supported by UBI */
 211 #define MAX_UBI_MTD_NAME_LEN 127
 212
 213 /* Maximum amount of UBI volumes that can be re-named at one go */
 214 #define UBI_MAX_RNVOL 32
 215
 216 /*
 217  * UBI volume type constants.
 218  *
 219  * @UBI_DYNAMIC_VOLUME: dynamic volume
 220  * @UBI_STATIC_VOLUME:  static volume
 221  */
 222 enum {
 223         UBI_DYNAMIC_VOLUME = 3,
 224         UBI_STATIC_VOLUME  = 4,
 225 };
 226
 227 /*
 228  * UBI set volume property ioctl constants.
 229  *
 230  * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
 231  *                             user to directly write and erase individual
 232  *                             eraseblocks on dynamic volumes
 233  */
 234 enum {
 235         UBI_VOL_PROP_DIRECT_WRITE = 1,
 236 };
 237
 238 /**
 239  * struct ubi_attach_req - attach MTD device request.
 240  * @ubi_num: UBI device number to create
 241  * @mtd_num: MTD device number to attach
 242  * @vid_hdr_offset: VID header offset (use defaults if %0)
 243  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
 244  * @padding: reserved for future, not used, has to be zeroed
 245  *
 246  * This data structure is used to specify MTD device UBI has to attach and the
 247  * parameters it has to use. The number which should be assigned to the new UBI
 248  * device is passed in @ubi_num. UBI may automatically assign the number if
 249  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 250  * @ubi_num.
 251  *
 252  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 253  * offset of the VID header within physical eraseblocks. The default offset is
 254  * the next min. I/O unit after the EC header. For example, it will be offset
 255  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 256  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 257  *
 258  * But in rare cases, if this optimizes things, the VID header may be placed to
 259  * a different offset. For example, the boot-loader might do things faster if
 260  * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
 261  * As the boot-loader would not normally need to read EC headers (unless it
 262  * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
 263  * example, but it real-life example. So, in this example, @vid_hdr_offer would
 264  * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 265  * aligned, which is OK, as UBI is clever enough to realize this is 4th
 266  * sub-page of the first page and add needed padding.
 267  *
 268  * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
 269  * UBI device per 1024 eraseblocks.  This value is often given in an other form
 270  * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
 271  * maximum expected bad eraseblocks per 1024 is then:
 272  *    1024 * (1 - MinNVB / MaxNVB)
 273  * Which gives 20 for most NAND devices.  This limit is used in order to derive
 274  * amount of eraseblock UBI reserves for handling new bad blocks. If the device
 275  * has more bad eraseblocks than this limit, UBI does not reserve any physical
 276  * eraseblocks for new bad eraseblocks, but attempts to use available
 277  * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
 278  * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
 279  */
 280 struct ubi_attach_req {
 281         __s32 ubi_num;
 282         __s32 mtd_num;
 283         __s32 vid_hdr_offset;
 284         __s16 max_beb_per1024;
 285         __s8 padding[10];
 286 };
 287
 288 /**
 289  * struct ubi_mkvol_req - volume description data structure used in
 290  *                        volume creation requests.
 291  * @vol_id: volume number
 292  * @alignment: volume alignment
 293  * @bytes: volume size in bytes
 294  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 295  * @padding1: reserved for future, not used, has to be zeroed
 296  * @name_len: volume name length
 297  * @padding2: reserved for future, not used, has to be zeroed
 298  * @name: volume name
 299  *
 300  * This structure is used by user-space programs when creating new volumes. The
 301  * @used_bytes field is only necessary when creating static volumes.
 302  *
 303  * The @alignment field specifies the required alignment of the volume logical
 304  * eraseblock. This means, that the size of logical eraseblocks will be aligned
 305  * to this number, i.e.,
 306  *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 307  *
 308  * To put it differently, the logical eraseblock of this volume may be slightly
 309  * shortened in order to make it properly aligned. The alignment has to be
 310  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 311  * available space of logical eraseblocks.
 312  *
 313  * The @alignment field may be useful, for example, when one wants to maintain
 314  * a block device on top of an UBI volume. In this case, it is desirable to fit
 315  * an integer number of blocks in logical eraseblocks of this UBI volume. With
 316  * alignment it is possible to update this volume using plane UBI volume image
 317  * BLOBs, without caring about how to properly align them.
 318  */
 319 struct ubi_mkvol_req {
 320         __s32 vol_id;
 321         __s32 alignment;
 322         __s64 bytes;
 323         __s8 vol_type;
 324         __s8 padding1;
 325         __s16 name_len;
 326         __s8 padding2[4];
 327         char name[UBI_MAX_VOLUME_NAME + 1];
 328 } __packed;
 329
 330 /**
 331  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 332  * @vol_id: ID of the volume to re-size
 333  * @bytes: new size of the volume in bytes
 334  *
 335  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 336  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 337  * smaller than the number of bytes they bear. To arbitrarily shrink a static
 338  * volume, it must be wiped out first (by means of volume update operation with
 339  * zero number of bytes).
 340  */
 341 struct ubi_rsvol_req {
 342         __s64 bytes;
 343         __s32 vol_id;
 344 } __packed;
 345
 346 /**
 347  * struct ubi_rnvol_req - volumes re-name request.
 348  * @count: count of volumes to re-name
 349  * @padding1:  reserved for future, not used, has to be zeroed
 350  * @vol_id: ID of the volume to re-name
 351  * @name_len: name length
 352  * @padding2:  reserved for future, not used, has to be zeroed
 353  * @name: new volume name
 354  *
 355  * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
 356  * re-name is specified in the @count field. The ID of the volumes to re-name
 357  * and the new names are specified in the @vol_id and @name fields.
 358  *
 359  * The UBI volume re-name operation is atomic, which means that should power cut
 360  * happen, the volumes will have either old name or new name. So the possible
 361  * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
 362  * A and B one may create temporary volumes %A1 and %B1 with the new contents,
 363  * then atomically re-name A1->A and B1->B, in which case old %A and %B will
 364  * be removed.
 365  *
 366  * If it is not desirable to remove old A and B, the re-name request has to
 367  * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
 368  * become A and B, and old A and B will become A1 and B1.
 369  *
 370  * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
 371  * and B1 become A and B, and old A and B become X and Y.
 372  *
 373  * In other words, in case of re-naming into an existing volume name, the
 374  * existing volume is removed, unless it is re-named as well at the same
 375  * re-name request.
 376  */
 377 struct ubi_rnvol_req {
 378         __s32 count;
 379         __s8 padding1[12];
 380         struct {
 381                 __s32 vol_id;
 382                 __s16 name_len;
 383                 __s8  padding2[2];
 384                 char    name[UBI_MAX_VOLUME_NAME + 1];
 385         } ents[UBI_MAX_RNVOL];
 386 } __packed;
 387
 388 /**
 389  * struct ubi_leb_change_req - a data structure used in atomic LEB change
 390  *                             requests.
 391  * @lnum: logical eraseblock number to change
 392  * @bytes: how many bytes will be written to the logical eraseblock
 393  * @dtype: pass "3" for better compatibility with old kernels
 394  * @padding: reserved for future, not used, has to be zeroed
 395  *
 396  * The @dtype field used to inform UBI about what kind of data will be written
 397  * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
 398  * UBI tried to pick a PEB with lower erase counter for short term data and a
 399  * PEB with higher erase counter for long term data. But this was not really
 400  * used because users usually do not know this and could easily mislead UBI. We
 401  * removed this feature in May 2012. UBI currently just ignores the @dtype
 402  * field. But for better compatibility with older kernels it is recommended to
 403  * set @dtype to 3 (unknown).
 404  */
 405 struct ubi_leb_change_req {
 406         __s32 lnum;
 407         __s32 bytes;
 408         __s8  dtype; /* obsolete, do not use! */
 409         __s8  padding[7];
 410 } __packed;
 411
 412 /**
 413  * struct ubi_map_req - a data structure used in map LEB requests.
 414  * @dtype: pass "3" for better compatibility with old kernels
 415  * @lnum: logical eraseblock number to unmap
 416  * @padding: reserved for future, not used, has to be zeroed
 417  */
 418 struct ubi_map_req {
 419         __s32 lnum;
 420         __s8  dtype; /* obsolete, do not use! */
 421         __s8  padding[3];
 422 } __packed;
 423
 424
 425 /**
 426  * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
 427  *                               property.
 428  * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
 429  * @padding: reserved for future, not used, has to be zeroed
 430  * @value: value to set
 431  */
 432 struct ubi_set_vol_prop_req {
 433         __u8  property;
 434         __u8  padding[7];
 435         __u64 value;
 436 }  __packed;
 437
 438 /**
 439  * struct ubi_blkcreate_req - a data structure used in block creation requests.
 440  * @padding: reserved for future, not used, has to be zeroed
 441  */
 442 struct ubi_blkcreate_req {
 443         __s8  padding[128];
 444 }  __packed;
 445
 446 #endif /* __UBI_USER_H__ */