include/mtd/ubi-user.h

   1 /*
   2  * Copyright (c) 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 volume update
  62  * ~~~~~~~~~~~~~~~~~
  63  *
  64  * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
  65  * corresponding UBI volume character device. A pointer to a 64-bit update
  66  * size should be passed to the IOCTL. After this, UBI expects user to write
  67  * this number of bytes to the volume character device. The update is finished
  68  * when the claimed number of bytes is passed. So, the volume update sequence
  69  * is something like:
  70  *
  71  * fd = open("/dev/my_volume");
  72  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  73  * write(fd, buf, image_size);
  74  * close(fd);
  75  *
  76  * Atomic eraseblock change
  77  * ~~~~~~~~~~~~~~~~~~~~~~~~
  78  *
  79  * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
  80  * command of the corresponding UBI volume character device. A pointer to
  81  * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
  82  * expected to write the requested amount of bytes. This is similar to the
  83  * "volume update" IOCTL.
  84  */
  85
  86 /*
  87  * When a new UBI volume or UBI device is created, users may either specify the
  88  * volume/device number they want to create or to let UBI automatically assign
  89  * the number using these constants.
  90  */
  91 #define UBI_VOL_NUM_AUTO (-1)
  92 #define UBI_DEV_NUM_AUTO (-1)
  93
  94 /* Maximum volume name length */
  95 #define UBI_MAX_VOLUME_NAME 127
  96
  97 /* IOCTL commands of UBI character devices */
  98
  99 #define UBI_IOC_MAGIC 'o'
 100
 101 /* Create an UBI volume */
 102 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
 103 /* Remove an UBI volume */
 104 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
 105 /* Re-size an UBI volume */
 106 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
 107
 108 /* IOCTL commands of the UBI control character device */
 109
 110 #define UBI_CTRL_IOC_MAGIC 'o'
 111
 112 /* Attach an MTD device */
 113 #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
 114 /* Detach an MTD device */
 115 #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)
 116
 117 /* IOCTL commands of UBI volume character devices */
 118
 119 #define UBI_VOL_IOC_MAGIC 'O'
 120
 121 /* Start UBI volume update */
 122 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
 123 /* An eraseblock erasure command, used for debugging, disabled by default */
 124 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
 125 /* An atomic eraseblock change command */
 126 #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
 127
 128 /* Maximum MTD device name length supported by UBI */
 129 #define MAX_UBI_MTD_NAME_LEN 127
 130
 131 /*
 132  * UBI data type hint constants.
 133  *
 134  * UBI_LONGTERM: long-term data
 135  * UBI_SHORTTERM: short-term data
 136  * UBI_UNKNOWN: data persistence is unknown
 137  *
 138  * These constants are used when data is written to UBI volumes in order to
 139  * help the UBI wear-leveling unit to find more appropriate physical
 140  * eraseblocks.
 141  */
 142 enum {
 143         UBI_LONGTERM  = 1,
 144         UBI_SHORTTERM = 2,
 145         UBI_UNKNOWN   = 3,
 146 };
 147
 148 /*
 149  * UBI volume type constants.
 150  *
 151  * @UBI_DYNAMIC_VOLUME: dynamic volume
 152  * @UBI_STATIC_VOLUME:  static volume
 153  */
 154 enum {
 155         UBI_DYNAMIC_VOLUME = 3,
 156         UBI_STATIC_VOLUME  = 4,
 157 };
 158
 159 /**
 160  * struct ubi_attach_req - attach MTD device request.
 161  * @ubi_num: UBI device number to create
 162  * @mtd_num: MTD device number to attach
 163  * @vid_hdr_offset: VID header offset (use defaults if %0)
 164  * @padding: reserved for future, not used, has to be zeroed
 165  *
 166  * This data structure is used to specify MTD device UBI has to attach and the
 167  * parameters it has to use. The number which should be assigned to the new UBI
 168  * device is passed in @ubi_num. UBI may automatically assign the number if
 169  * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 170  * @ubi_num.
 171  *
 172  * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 173  * offset of the VID header within physical eraseblocks. The default offset is
 174  * the next min. I/O unit after the EC header. For example, it will be offset
 175  * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 176  * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 177  *
 178  * But in rare cases, if this optimizes things, the VID header may be placed to
 179  * a different offset. For example, the boot-loader might do things faster if the
 180  * VID header sits at the end of the first 2KiB NAND page with 4 sub-pages. As
 181  * the boot-loader would not normally need to read EC headers (unless it needs
 182  * UBI in RW mode), it might be faster to calculate ECC. This is weird example,
 183  * but it real-life example. So, in this example, @vid_hdr_offer would be
 184  * 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 185  * aligned, which is OK, as UBI is clever enough to realize this is 4th sub-page
 186  * of the first page and add needed padding.
 187  */
 188 struct ubi_attach_req {
 189         int32_t ubi_num;
 190         int32_t mtd_num;
 191         int32_t vid_hdr_offset;
 192         uint8_t padding[12];
 193 };
 194
 195 /**
 196  * struct ubi_mkvol_req - volume description data structure used in
 197  *                        volume creation requests.
 198  * @vol_id: volume number
 199  * @alignment: volume alignment
 200  * @bytes: volume size in bytes
 201  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 202  * @padding1: reserved for future, not used, has to be zeroed
 203  * @name_len: volume name length
 204  * @padding2: reserved for future, not used, has to be zeroed
 205  * @name: volume name
 206  *
 207  * This structure is used by user-space programs when creating new volumes. The
 208  * @used_bytes field is only necessary when creating static volumes.
 209  *
 210  * The @alignment field specifies the required alignment of the volume logical
 211  * eraseblock. This means, that the size of logical eraseblocks will be aligned
 212  * to this number, i.e.,
 213  *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 214  *
 215  * To put it differently, the logical eraseblock of this volume may be slightly
 216  * shortened in order to make it properly aligned. The alignment has to be
 217  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 218  * available space of logical eraseblocks.
 219  *
 220  * The @alignment field may be useful, for example, when one wants to maintain
 221  * a block device on top of an UBI volume. In this case, it is desirable to fit
 222  * an integer number of blocks in logical eraseblocks of this UBI volume. With
 223  * alignment it is possible to update this volume using plane UBI volume image
 224  * BLOBs, without caring about how to properly align them.
 225  */
 226 struct ubi_mkvol_req {
 227         int32_t vol_id;
 228         int32_t alignment;
 229         int64_t bytes;
 230         int8_t vol_type;
 231         int8_t padding1;
 232         int16_t name_len;
 233         int8_t padding2[4];
 234         char name[UBI_MAX_VOLUME_NAME + 1];
 235 } __attribute__ ((packed));
 236
 237 /**
 238  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 239  * @vol_id: ID of the volume to re-size
 240  * @bytes: new size of the volume in bytes
 241  *
 242  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 243  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 244  * smaller then the number of bytes they bear. To arbitrarily shrink a static
 245  * volume, it must be wiped out first (by means of volume update operation with
 246  * zero number of bytes).
 247  */
 248 struct ubi_rsvol_req {
 249         int64_t bytes;
 250         int32_t vol_id;
 251 } __attribute__ ((packed));
 252
 253 /**
 254  * struct ubi_leb_change_req - a data structure used in atomic logical
 255  *                             eraseblock change requests.
 256  * @lnum: logical eraseblock number to change
 257  * @bytes: how many bytes will be written to the logical eraseblock
 258  * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
 259  * @padding: reserved for future, not used, has to be zeroed
 260  */
 261 struct ubi_leb_change_req {
 262         int32_t lnum;
 263         int32_t bytes;
 264         uint8_t dtype;
 265         uint8_t padding[7];
 266 } __attribute__ ((packed));
 267
 268 #endif /* __UBI_USER_H__ */