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 volume creation
  26  * ~~~~~~~~~~~~~~~~~~~
  27  *
  28  * UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character
  29  * device. A &struct ubi_mkvol_req object has to be properly filled and a
  30  * pointer to it has to be passed to the IOCTL.
  31  *
  32  * UBI volume deletion
  33  * ~~~~~~~~~~~~~~~~~~~
  34  *
  35  * To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character
  36  * device should be used. A pointer to the 32-bit volume ID hast to be passed
  37  * to the IOCTL.
  38  *
  39  * UBI volume re-size
  40  * ~~~~~~~~~~~~~~~~~~
  41  *
  42  * To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character
  43  * device should be used. A &struct ubi_rsvol_req object has to be properly
  44  * filled and a pointer to it has to be passed to the IOCTL.
  45  *
  46  * UBI volume update
  47  * ~~~~~~~~~~~~~~~~~
  48  *
  49  * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
  50  * corresponding UBI volume character device. A pointer to a 64-bit update
  51  * size should be passed to the IOCTL. After then, UBI expects user to write
  52  * this number of bytes to the volume character device. The update is finished
  53  * when the claimed number of bytes is passed. So, the volume update sequence
  54  * is something like:
  55  *
  56  * fd = open("/dev/my_volume");
  57  * ioctl(fd, UBI_IOCVOLUP, &image_size);
  58  * write(fd, buf, image_size);
  59  * close(fd);
  60  */
  61
  62 /*
  63  * When a new volume is created, users may either specify the volume number they
  64  * want to create or to let UBI automatically assign a volume number using this
  65  * constant.
  66  */
  67 #define UBI_VOL_NUM_AUTO (-1)
  68
  69 /* Maximum volume name length */
  70 #define UBI_MAX_VOLUME_NAME 127
  71
  72 /* IOCTL commands of UBI character devices */
  73
  74 #define UBI_IOC_MAGIC 'o'
  75
  76 /* Create an UBI volume */
  77 #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
  78 /* Remove an UBI volume */
  79 #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
  80 /* Re-size an UBI volume */
  81 #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
  82
  83 /* IOCTL commands of UBI volume character devices */
  84
  85 #define UBI_VOL_IOC_MAGIC 'O'
  86
  87 /* Start UBI volume update */
  88 #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
  89 /* An eraseblock erasure command, used for debugging, disabled by default */
  90 #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
  91
  92 /*
  93  * UBI volume type constants.
  94  *
  95  * @UBI_DYNAMIC_VOLUME: dynamic volume
  96  * @UBI_STATIC_VOLUME:  static volume
  97  */
  98 enum {
  99         UBI_DYNAMIC_VOLUME = 3,
 100         UBI_STATIC_VOLUME = 4
 101 };
 102
 103 /**
 104  * struct ubi_mkvol_req - volume description data structure used in
 105  * volume creation requests.
 106  * @vol_id: volume number
 107  * @alignment: volume alignment
 108  * @bytes: volume size in bytes
 109  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 110  * @padding1: reserved for future, not used
 111  * @name_len: volume name length
 112  * @padding2: reserved for future, not used
 113  * @name: volume name
 114  *
 115  * This structure is used by userspace programs when creating new volumes. The
 116  * @used_bytes field is only necessary when creating static volumes.
 117  *
 118  * The @alignment field specifies the required alignment of the volume logical
 119  * eraseblock. This means, that the size of logical eraseblocks will be aligned
 120  * to this number, i.e.,
 121  *      (UBI device logical eraseblock size) mod (@alignment) = 0.
 122  *
 123  * To put it differently, the logical eraseblock of this volume may be slightly
 124  * shortened in order to make it properly aligned. The alignment has to be
 125  * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 126  * available space of logical eraseblocks.
 127  *
 128  * The @alignment field may be useful, for example, when one wants to maintain
 129  * a block device on top of an UBI volume. In this case, it is desirable to fit
 130  * an integer number of blocks in logical eraseblocks of this UBI volume. With
 131  * alignment it is possible to update this volume using plane UBI volume image
 132  * BLOBs, without caring about how to properly align them.
 133  */
 134 struct ubi_mkvol_req {
 135         int32_t vol_id;
 136         int32_t alignment;
 137         int64_t bytes;
 138         int8_t vol_type;
 139         int8_t padding1;
 140         int16_t name_len;
 141         int8_t padding2[4];
 142         char name[UBI_MAX_VOLUME_NAME+1];
 143 } __attribute__ ((packed));
 144
 145 /**
 146  * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 147  * @vol_id: ID of the volume to re-size
 148  * @bytes: new size of the volume in bytes
 149  *
 150  * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 151  * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 152  * smaller then the number of bytes they bear. To arbitrarily shrink a static
 153  * volume, it must be wiped out first (by means of volume update operation with
 154  * zero number of bytes).
 155  */
 156 struct ubi_rsvol_req {
 157         int64_t bytes;
 158         int32_t vol_id;
 159 } __attribute__ ((packed));
 160
 161 #endif /* __UBI_USER_H__ */