libubi/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 /*
  25  * UBI device creation (the same as MTD device attachment)
  26  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  27  *
  28  * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
  29  * control device. The caller has to properly fill and pass
  30  * &struct ubi_attach_req object - UBI will attach the MTD device specified in
  31  * the request and return the newly created UBI device number as the ioctl
  32  * return value.
  33  *
  34  * UBI device deletion (the same as MTD device detachment)
  35  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  36  *
  37  * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
  38  * control device.
  39  *
  40  * UBI volume creation
  41  * ~~~~~~~~~~~~~~~~~~~
  42  *
  43  * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
  44  * device. A &struct ubi_mkvol_req object has to be properly filled and a
  45  * pointer to it has to be passed to the ioctl.
  46  *
  47  * UBI volume deletion
  48  * ~~~~~~~~~~~~~~~~~~~
  49  *
  50  * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
  51  * device should be used. A pointer to the 32-bit volume ID hast to be passed
  52  * to the ioctl.
  53  *
  54  * UBI volume re-size
  55  * ~~~~~~~~~~~~~~~~~~
  56  *
  57  * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
  58  * device should be used. A &struct ubi_rsvol_req object has to be properly
  59  * filled and a pointer to it has to be passed to the ioctl.
  60  *
  61  * UBI volumes re-name
  62  * ~~~~~~~~~~~~~~~~~~~
  63  *
  64  * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
  65  * of the UBI character device should be used. A &struct ubi_rnvol_req object
  66  * has to be properly filled and a pointer to it has to be passed to the ioctl.
  67  *
  68  * UBI volume update
  69  * ~~~~~~~~~~~~~~~~~
  70  *
  71  * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
  72  * corresponding UBI volume character device. A pointer to a 64-bit update
  73  * size should be passed to the ioctl. After this, UBI expects user to write
  74  * this number of bytes to the volume character device. The update is finished
  75  * when the claimed number of bytes is passed. So, the volume update sequence
  76  * is something like:
  77  *
  78  * fd = open("/dev/my_volume");
  79  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  80  * write(fd, buf, image_size);
  81  * close(fd);
  82  *
  83  * Logical eraseblock erase
  84  * ~~~~~~~~~~~~~~~~~~~~~~~~
  85  *
  86  * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
  87  * corresponding UBI volume character device should be used. This command
  88  * unmaps the requested logical eraseblock, makes sure the corresponding
  89  * physical eraseblock is successfully erased, and returns.
  90  *
  91  * Atomic logical eraseblock change
  92  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  93  *
  94  * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
  95  * ioctl command of the corresponding UBI volume character device. A pointer to
  96  * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
  97  * user is expected to write the requested amount of bytes (similarly to what
  98  * should be done in case of the "volume update" ioctl).
  99  *
 100  * Logical eraseblock map
 101  * ~~~~~~~~~~~~~~~~~~~~~
 102  *
 103  * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
 104  * ioctl command should be used. A pointer to a &struct ubi_map_req object is
 105  * expected to be passed. The ioctl maps the requested logical eraseblock to
 106  * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
 107  * be mapped. If the logical eraseblock specified in the request is already
 108  * mapped to a physical eraseblock, the ioctl fails and returns error.
 109  *
 110  * Logical eraseblock unmap
 111  * ~~~~~~~~~~~~~~~~~~~~~~~~
 112  *
 113  * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
 114  * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
 115  * schedules corresponding physical eraseblock for erasure, and returns. Unlike
 116  * the "LEB erase" command, it does not wait for the physical eraseblock being
 117  * erased. Note, the side effect of this is that if an unclean reboot happens
 118  * after the unmap ioctl returns, you may find the LEB mapped again to the same
 119  * physical eraseblock after the UBI is run again.
 120  *
 121  * Check if logical eraseblock is mapped
 122  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 123  *
 124  * To check if a logical eraseblock is mapped to a physical eraseblock, the
 125  * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
 126  * not mapped, and %1 if it is mapped.
 127  *
 128  * Set an UBI volume property
 129  * ~~~~~~~~~~~~~~~~~~~~~~~~~
 130  *
 131  * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
 132  * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
 133  * passed. The object describes which property should be set, and to which value
 134  * it should be set.
 135  */
 136
 137 /*
 138  * When a new UBI volume or UBI device is created, users may either specify the
 139  * volume/device number they want to create or to let UBI automatically assign
 140  * the number using these constants.
 141  */
 142 #define UBI_VOL_NUM_AUTO (-1)
 143 #define UBI_DEV_NUM_AUTO (-1)
 144
 145 /* Maximum volume name length */
 146 #define UBI_MAX_VOLUME_NAME 127
 147
 148 /* ioctl commands of UBI character devices */
 149
 150 #define UBI_IOC_MAGIC 'o'
 151
 152 /* Create an UBI volume */
 153 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
 154 /* Remove an UBI volume */
 155 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
 156 /* Re-size an UBI volume */
 157 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
 158 /* Re-name volumes */
 159 #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
 160
 161 /* ioctl commands of the UBI control character device */
 162
 163 #define UBI_CTRL_IOC_MAGIC 'o'
 164
 165 /* Attach an MTD device */
 166 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
 167 /* Detach an MTD device */
 168 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)
 169
 170 /* ioctl commands of UBI volume character devices */
 171
 172 #define UBI_VOL_IOC_MAGIC 'O'
 173
 174 /* Start UBI volume update */
 175 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
 176 /* LEB erasure command, used for debugging, disabled by default */
 177 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
 178 /* Atomic LEB change command */
 179 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
 180 /* Map LEB command */
 181 #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
 182 /* Unmap LEB command */
 183 #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, int32_t)
 184 /* Check if LEB is mapped command */
 185 #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, int32_t)
 186 /* Set an UBI volume property */
 187 #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
 188                                struct ubi_set_vol_prop_req)
 189
 190 /* Maximum MTD device name length supported by UBI */
 191 #define MAX_UBI_MTD_NAME_LEN 127
 192
 193 /* Maximum amount of UBI volumes that can be re-named at one go */
 194 #define UBI_MAX_RNVOL 32
 195
 196 /*
 197  * UBI volume type constants.
 198  *
 199  * @UBI_DYNAMIC_VOLUME: dynamic volume
 200  * @UBI_STATIC_VOLUME:  static volume
 201  */
 202 enum {
 203         UBI_DYNAMIC_VOLUME = 3,
 204         UBI_STATIC_VOLUME  = 4,
 205 };
 206
 207 /*
 208  * UBI set volume property ioctl constants.
 209  *
 210  * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
 211  *                             user to directly write and erase individual
 212  *                             eraseblocks on dynamic volumes
 213  */
 214 enum {
 215         UBI_VOL_PROP_DIRECT_WRITE = 1,
 216 };
 217
 218 /**
 219  * struct ubi_attach_req - attach MTD device request.
 220  * @ubi_num: UBI device number to create
 221  * @mtd_num: MTD device number to attach
 222  * @vid_hdr_offset: VID header offset (use defaults if %0)
 223  * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
 224  * @padding: reserved for future, not used, has to be zeroed
 225  *
 226  * This data structure is used to specify MTD device UBI has to attach and the
 227  * parameters it has to use. The number which should be assigned to the new UBI
 228  * device is passed in @ubi_num. UBI may automatically assign the number if
 229  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 230  * @ubi_num.
 231  *
 232  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 233  * offset of the VID header within physical eraseblocks. The default offset is
 234  * the next min. I/O unit after the EC header. For example, it will be offset
 235  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 236  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 237  *
 238  * But in rare cases, if this optimizes things, the VID header may be placed to
 239  * a different offset. For example, the boot-loader might do things faster if
 240  * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
 241  * As the boot-loader would not normally need to read EC headers (unless it
 242  * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
 243  * example, but it real-life example. So, in this example, @vid_hdr_offer would
 244  * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 245  * aligned, which is OK, as UBI is clever enough to realize this is 4th
 246  * sub-page of the first page and add needed padding.
 247  *
 248  * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
 249  * UBI device per 1024 eraseblocks.  This value is often given in an other form
 250  * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
 251  * maximum expected bad eraseblocks per 1024 is then:
 252  *    1024 * (1 - MinNVB / MaxNVB)
 253  * Which gives 20 for most NAND devices.  This limit is used in order to derive
 254  * amount of eraseblock UBI reserves for handling new bad blocks. If the device
 255  * has more bad eraseblocks than this limit, UBI does not reserve any physical
 256  * eraseblocks for new bad eraseblocks, but attempts to use available
 257  * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
 258  * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
 259  */
 260 struct ubi_attach_req {
 261         int32_t ubi_num;
 262         int32_t mtd_num;
 263         int32_t vid_hdr_offset;
 264         int16_t max_beb_per1024;
 265         int8_t  padding[10];
 266 };
 267
 268 /**
 269  * struct ubi_mkvol_req - volume description data structure used in
 270  *                        volume creation requests.
 271  * @vol_id: volume number
 272  * @alignment: volume alignment
 273  * @bytes: volume size in bytes
 274  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 275  * @padding1: reserved for future, not used, has to be zeroed
 276  * @name_len: volume name length
 277  * @padding2: reserved for future, not used, has to be zeroed
 278  * @name: volume name
 279  *
 280  * This structure is used by user-space programs when creating new volumes. The
 281  * @used_bytes field is only necessary when creating static volumes.
 282  *
 283  * The @alignment field specifies the required alignment of the volume logical
 284  * eraseblock. This means, that the size of logical eraseblocks will be aligned
 285  * to this number, i.e.,
 286  *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 287  *
 288  * To put it differently, the logical eraseblock of this volume may be slightly
 289  * shortened in order to make it properly aligned. The alignment has to be
 290  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 291  * available space of logical eraseblocks.
 292  *
 293  * The @alignment field may be useful, for example, when one wants to maintain
 294  * a block device on top of an UBI volume. In this case, it is desirable to fit
 295  * an integer number of blocks in logical eraseblocks of this UBI volume. With
 296  * alignment it is possible to update this volume using plane UBI volume image
 297  * BLOBs, without caring about how to properly align them.
 298  */
 299 struct ubi_mkvol_req {
 300         int32_t vol_id;
 301         int32_t alignment;
 302         int64_t bytes;
 303         int8_t vol_type;
 304         int8_t padding1;
 305         int16_t name_len;
 306         int8_t padding2[4];
 307         char name[UBI_MAX_VOLUME_NAME + 1];
 308 } __attribute__((packed));
 309
 310 /**
 311  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 312  * @vol_id: ID of the volume to re-size
 313  * @bytes: new size of the volume in bytes
 314  *
 315  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 316  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 317  * smaller than the number of bytes they bear. To arbitrarily shrink a static
 318  * volume, it must be wiped out first (by means of volume update operation with
 319  * zero number of bytes).
 320  */
 321 struct ubi_rsvol_req {
 322         int64_t bytes;
 323         int32_t vol_id;
 324 } __attribute__((packed));
 325
 326 /**
 327  * struct ubi_rnvol_req - volumes re-name request.
 328  * @count: count of volumes to re-name
 329  * @padding1:  reserved for future, not used, has to be zeroed
 330  * @vol_id: ID of the volume to re-name
 331  * @name_len: name length
 332  * @padding2:  reserved for future, not used, has to be zeroed
 333  * @name: new volume name
 334  *
 335  * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
 336  * re-name is specified in the @count field. The ID of the volumes to re-name
 337  * and the new names are specified in the @vol_id and @name fields.
 338  *
 339  * The UBI volume re-name operation is atomic, which means that should power cut
 340  * happen, the volumes will have either old name or new name. So the possible
 341  * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
 342  * A and B one may create temporary volumes %A1 and %B1 with the new contents,
 343  * then atomically re-name A1->A and B1->B, in which case old %A and %B will
 344  * be removed.
 345  *
 346  * If it is not desirable to remove old A and B, the re-name request has to
 347  * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
 348  * become A and B, and old A and B will become A1 and B1.
 349  *
 350  * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
 351  * and B1 become A and B, and old A and B become X and Y.
 352  *
 353  * In other words, in case of re-naming into an existing volume name, the
 354  * existing volume is removed, unless it is re-named as well at the same
 355  * re-name request.
 356  */
 357 struct ubi_rnvol_req {
 358         int32_t count;
 359         int8_t padding1[12];
 360         struct {
 361                 int32_t vol_id;
 362                 int16_t name_len;
 363                 int8_t  padding2[2];
 364                 char    name[UBI_MAX_VOLUME_NAME + 1];
 365         } ents[UBI_MAX_RNVOL];
 366 } __attribute__((packed));
 367
 368 /**
 369  * struct ubi_leb_change_req - a data structure used in atomic LEB change
 370  *                             requests.
 371  * @lnum: logical eraseblock number to change
 372  * @bytes: how many bytes will be written to the logical eraseblock
 373  * @dtype: pass "3" for better compatibility with old kernels
 374  * @padding: reserved for future, not used, has to be zeroed
 375  *
 376  * The @dtype field used to inform UBI about what kind of data will be written
 377  * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
 378  * UBI tried to pick a PEB with lower erase counter for short term data and a
 379  * PEB with higher erase counter for long term data. But this was not really
 380  * used because users usually do not know this and could easily mislead UBI. We
 381  * removed this feature in May 2012. UBI currently just ignores the @dtype
 382  * field. But for better compatibility with older kernels it is recommended to
 383  * set @dtype to 3 (unknown).
 384  */
 385 struct ubi_leb_change_req {
 386         int32_t lnum;
 387         int32_t bytes;
 388         int8_t  dtype; /* obsolete, do not use! */
 389         int8_t  padding[7];
 390 } __attribute__((packed));
 391
 392 /**
 393  * struct ubi_map_req - a data structure used in map LEB requests.
 394  * @dtype: pass "3" for better compatibility with old kernels
 395  * @lnum: logical eraseblock number to unmap
 396  * @padding: reserved for future, not used, has to be zeroed
 397  */
 398 struct ubi_map_req {
 399         int32_t lnum;
 400         int8_t  dtype; /* obsolete, do not use! */
 401         int8_t  padding[3];
 402 } __attribute__((packed));
 403
 404
 405 /**
 406  * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
 407  *                               property.
 408  * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
 409  * @padding: reserved for future, not used, has to be zeroed
 410  * @value: value to set
 411  */
 412 struct ubi_set_vol_prop_req {
 413         uint8_t  property;
 414         uint8_t  padding[7];
 415         uint64_t value;
 416 }  __attribute__((packed));
 417
 418 #endif /* __UBI_USER_H__ */