include/uapi/mtd/ubi-user.h

   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  * Block devices on UBI volumes
 139  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 140  *
 141  * To attach or detach a block device from an UBI volume the %UBI_IOCVOLATTBLK
 142  * and %UBI_IOCVOLDETBLK ioctl commands should be used, respectively.
 143  * These commands take no arguments.
 144  */
 145
 146 /*
 147  * When a new UBI volume or UBI device is created, users may either specify the
 148  * volume/device number they want to create or to let UBI automatically assign
 149  * the number using these constants.
 150  */
 151 #define UBI_VOL_NUM_AUTO (-1)
 152 #define UBI_DEV_NUM_AUTO (-1)
 153
 154 /* Maximum volume name length */
 155 #define UBI_MAX_VOLUME_NAME 127
 156
 157 /* ioctl commands of UBI character devices */
 158
 159 #define UBI_IOC_MAGIC 'o'
 160
 161 /* Create an UBI volume */
 162 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
 163 /* Remove an UBI volume */
 164 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
 165 /* Re-size an UBI volume */
 166 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
 167 /* Re-name volumes */
 168 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
 169
 170 /* ioctl commands of the UBI control character device */
 171
 172 #define UBI_CTRL_IOC_MAGIC 'o'
 173
 174 /* Attach an MTD device */
 175 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
 176 /* Detach an MTD device */
 177 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
 178
 179 /* ioctl commands of UBI volume character devices */
 180
 181 #define UBI_VOL_IOC_MAGIC 'O'
 182
 183 /* Start UBI volume update
 184  * Note: This actually takes a pointer (__s64*), but we can't change
 185  *       that without breaking the ABI on 32bit systems
 186  */
 187 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
 188 /* LEB erasure command, used for debugging, disabled by default */
 189 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
 190 /* Atomic LEB change command */
 191 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
 192 /* Map LEB command */
 193 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
 194 /* Unmap LEB command */
 195 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
 196 /* Check if LEB is mapped command */
 197 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
 198 /* Set an UBI volume property */
 199 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 200                                struct ubi_set_vol_prop_req)
 201 /* Attach a block device to an UBI volume */
 202 #define UBI_IOCVOLATTBLK _IO(UBI_VOL_IOC_MAGIC, 7)
 203 /* Detach a block device from an UBI volume */
 204 #define UBI_IOCVOLDETBLK _IO(UBI_VOL_IOC_MAGIC, 8)
 205
 206 /* Maximum MTD device name length supported by UBI */
 207 #define MAX_UBI_MTD_NAME_LEN 127
 208
 209 /* Maximum amount of UBI volumes that can be re-named at one go */
 210 #define UBI_MAX_RNVOL 32
 211
 212 /*
 213  * UBI volume type constants.
 214  *
 215  * @UBI_DYNAMIC_VOLUME: dynamic volume
 216  * @UBI_STATIC_VOLUME:  static volume
 217  */
 218 enum {
 219         UBI_DYNAMIC_VOLUME = 3,
 220         UBI_STATIC_VOLUME  = 4,
 221 };
 222
 223 /*
 224  * UBI set volume property ioctl constants.
 225  *
 226  * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
 227  *                             user to directly write and erase individual
 228  *                             eraseblocks on dynamic volumes
 229  */
 230 enum {
 231         UBI_VOL_PROP_DIRECT_WRITE = 1,
 232 };
 233
 234 /**
 235  * struct ubi_attach_req - attach MTD device request.
 236  * @ubi_num: UBI device number to create
 237  * @mtd_num: MTD device number to attach
 238  * @vid_hdr_offset: VID header offset (use defaults if %0)
 239  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
 240  * @padding: reserved for future, not used, has to be zeroed
 241  *
 242  * This data structure is used to specify MTD device UBI has to attach and the
 243  * parameters it has to use. The number which should be assigned to the new UBI
 244  * device is passed in @ubi_num. UBI may automatically assign the number if
 245  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 246  * @ubi_num.
 247  *
 248  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 249  * offset of the VID header within physical eraseblocks. The default offset is
 250  * the next min. I/O unit after the EC header. For example, it will be offset
 251  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 252  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 253  *
 254  * But in rare cases, if this optimizes things, the VID header may be placed to
 255  * a different offset. For example, the boot-loader might do things faster if
 256  * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
 257  * As the boot-loader would not normally need to read EC headers (unless it
 258  * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
 259  * example, but it real-life example. So, in this example, @vid_hdr_offer would
 260  * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 261  * aligned, which is OK, as UBI is clever enough to realize this is 4th
 262  * sub-page of the first page and add needed padding.
 263  *
 264  * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
 265  * UBI device per 1024 eraseblocks.  This value is often given in an other form
 266  * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
 267  * maximum expected bad eraseblocks per 1024 is then:
 268  *    1024 * (1 - MinNVB / MaxNVB)
 269  * Which gives 20 for most NAND devices.  This limit is used in order to derive
 270  * amount of eraseblock UBI reserves for handling new bad blocks. If the device
 271  * has more bad eraseblocks than this limit, UBI does not reserve any physical
 272  * eraseblocks for new bad eraseblocks, but attempts to use available
 273  * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
 274  * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
 275  */
 276 struct ubi_attach_req {
 277         __s32 ubi_num;
 278         __s32 mtd_num;
 279         __s32 vid_hdr_offset;
 280         __s16 max_beb_per1024;
 281         __s8 padding[10];
 282 };
 283
 284 /**
 285  * struct ubi_mkvol_req - volume description data structure used in
 286  *                        volume creation requests.
 287  * @vol_id: volume number
 288  * @alignment: volume alignment
 289  * @bytes: volume size in bytes
 290  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 291  * @padding1: reserved for future, not used, has to be zeroed
 292  * @name_len: volume name length
 293  * @padding2: reserved for future, not used, has to be zeroed
 294  * @name: volume name
 295  *
 296  * This structure is used by user-space programs when creating new volumes. The
 297  * @used_bytes field is only necessary when creating static volumes.
 298  *
 299  * The @alignment field specifies the required alignment of the volume logical
 300  * eraseblock. This means, that the size of logical eraseblocks will be aligned
 301  * to this number, i.e.,
 302  *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 303  *
 304  * To put it differently, the logical eraseblock of this volume may be slightly
 305  * shortened in order to make it properly aligned. The alignment has to be
 306  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 307  * available space of logical eraseblocks.
 308  *
 309  * The @alignment field may be useful, for example, when one wants to maintain
 310  * a block device on top of an UBI volume. In this case, it is desirable to fit
 311  * an integer number of blocks in logical eraseblocks of this UBI volume. With
 312  * alignment it is possible to update this volume using plane UBI volume image
 313  * BLOBs, without caring about how to properly align them.
 314  */
 315 struct ubi_mkvol_req {
 316         __s32 vol_id;
 317         __s32 alignment;
 318         __s64 bytes;
 319         __s8 vol_type;
 320         __s8 padding1;
 321         __s16 name_len;
 322         __s8 padding2[4];
 323         char name[UBI_MAX_VOLUME_NAME + 1];
 324 } __packed;
 325
 326 /**
 327  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 328  * @vol_id: ID of the volume to re-size
 329  * @bytes: new size of the volume in bytes
 330  *
 331  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 332  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 333  * smaller than the number of bytes they bear. To arbitrarily shrink a static
 334  * volume, it must be wiped out first (by means of volume update operation with
 335  * zero number of bytes).
 336  */
 337 struct ubi_rsvol_req {
 338         __s64 bytes;
 339         __s32 vol_id;
 340 } __packed;
 341
 342 /**
 343  * struct ubi_rnvol_req - volumes re-name request.
 344  * @count: count of volumes to re-name
 345  * @padding1:  reserved for future, not used, has to be zeroed
 346  * @vol_id: ID of the volume to re-name
 347  * @name_len: name length
 348  * @padding2:  reserved for future, not used, has to be zeroed
 349  * @name: new volume name
 350  *
 351  * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
 352  * re-name is specified in the @count field. The ID of the volumes to re-name
 353  * and the new names are specified in the @vol_id and @name fields.
 354  *
 355  * The UBI volume re-name operation is atomic, which means that should power cut
 356  * happen, the volumes will have either old name or new name. So the possible
 357  * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
 358  * A and B one may create temporary volumes %A1 and %B1 with the new contents,
 359  * then atomically re-name A1->A and B1->B, in which case old %A and %B will
 360  * be removed.
 361  *
 362  * If it is not desirable to remove old A and B, the re-name request has to
 363  * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
 364  * become A and B, and old A and B will become A1 and B1.
 365  *
 366  * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
 367  * and B1 become A and B, and old A and B become X and Y.
 368  *
 369  * In other words, in case of re-naming into an existing volume name, the
 370  * existing volume is removed, unless it is re-named as well at the same
 371  * re-name request.
 372  */
 373 struct ubi_rnvol_req {
 374         __s32 count;
 375         __s8 padding1[12];
 376         struct {
 377                 __s32 vol_id;
 378                 __s16 name_len;
 379                 __s8  padding2[2];
 380                 char    name[UBI_MAX_VOLUME_NAME + 1];
 381         } ents[UBI_MAX_RNVOL];
 382 } __packed;
 383
 384 /**
 385  * struct ubi_leb_change_req - a data structure used in atomic LEB change
 386  *                             requests.
 387  * @lnum: logical eraseblock number to change
 388  * @bytes: how many bytes will be written to the logical eraseblock
 389  * @dtype: pass "3" for better compatibility with old kernels
 390  * @padding: reserved for future, not used, has to be zeroed
 391  *
 392  * The @dtype field used to inform UBI about what kind of data will be written
 393  * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
 394  * UBI tried to pick a PEB with lower erase counter for short term data and a
 395  * PEB with higher erase counter for long term data. But this was not really
 396  * used because users usually do not know this and could easily mislead UBI. We
 397  * removed this feature in May 2012. UBI currently just ignores the @dtype
 398  * field. But for better compatibility with older kernels it is recommended to
 399  * set @dtype to 3 (unknown).
 400  */
 401 struct ubi_leb_change_req {
 402         __s32 lnum;
 403         __s32 bytes;
 404         __s8  dtype; /* obsolete, do not use! */
 405         __s8  padding[7];
 406 } __packed;
 407
 408 /**
 409  * struct ubi_map_req - a data structure used in map LEB requests.
 410  * @dtype: pass "3" for better compatibility with old kernels
 411  * @lnum: logical eraseblock number to unmap
 412  * @padding: reserved for future, not used, has to be zeroed
 413  */
 414 struct ubi_map_req {
 415         __s32 lnum;
 416         __s8  dtype; /* obsolete, do not use! */
 417         __s8  padding[3];
 418 } __packed;
 419
 420
 421 /**
 422  * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
 423  *                               property.
 424  * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
 425  * @padding: reserved for future, not used, has to be zeroed
 426  * @value: value to set
 427  */
 428 struct ubi_set_vol_prop_req {
 429         __u8  property;
 430         __u8  padding[7];
 431         __u64 value;
 432 }  __packed;
 433
 434 #endif /* __UBI_USER_H__ */