/*
   * Copyright © International Business Machines Corp., 2006
   *
   * SPDX-License-Identifier:    GPL-2.0+
   *
   * Author: Artem Bityutskiy (Битюцкий Артём)
   */
  
  #ifndef __UBI_USER_H__
  #define __UBI_USER_H__
  
  #include <linux/types.h>
  
  /*
   * UBI device creation (the same as MTD device attachment)
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
   * control device. The caller has to properly fill and pass
   * &struct ubi_attach_req object - UBI will attach the MTD device specified in
   * the request and return the newly created UBI device number as the ioctl
   * return value.
   *
   * UBI device deletion (the same as MTD device detachment)
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
   * control device.
   *
   * UBI volume creation
   * ~~~~~~~~~~~~~~~~~~~
   *
   * UBI volumes are created via the %UBI_IOCMKVOL ioctl command of UBI character
   * device. A &struct ubi_mkvol_req object has to be properly filled and a
   * pointer to it has to be passed to the ioctl.
   *
   * UBI volume deletion
   * ~~~~~~~~~~~~~~~~~~~
   *
   * To delete a volume, the %UBI_IOCRMVOL ioctl command of the UBI character
   * device should be used. A pointer to the 32-bit volume ID hast to be passed
   * to the ioctl.
   *
   * UBI volume re-size
   * ~~~~~~~~~~~~~~~~~~
   *
   * To re-size a volume, the %UBI_IOCRSVOL ioctl command of the UBI character
   * device should be used. A &struct ubi_rsvol_req object has to be properly
   * filled and a pointer to it has to be passed to the ioctl.
   *
   * UBI volumes re-name
   * ~~~~~~~~~~~~~~~~~~~
   *
   * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
   * of the UBI character device should be used. A &struct ubi_rnvol_req object
   * has to be properly filled and a pointer to it has to be passed to the ioctl.
   *
   * UBI volume update
   * ~~~~~~~~~~~~~~~~~
   *
   * Volume update should be done via the %UBI_IOCVOLUP ioctl command of the
   * corresponding UBI volume character device. A pointer to a 64-bit update
   * size should be passed to the ioctl. After this, UBI expects user to write
   * this number of bytes to the volume character device. The update is finished
   * when the claimed number of bytes is passed. So, the volume update sequence
   * is something like:
   *
   * fd = open("/dev/my_volume");
   * ioctl(fd, UBI_IOCVOLUP, &image_size);
   * write(fd, buf, image_size);
   * close(fd);
   *
   * Logical eraseblock erase
   * ~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * To erase a logical eraseblock, the %UBI_IOCEBER ioctl command of the
   * corresponding UBI volume character device should be used. This command
   * unmaps the requested logical eraseblock, makes sure the corresponding
   * physical eraseblock is successfully erased, and returns.
   *
   * Atomic logical eraseblock change
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * Atomic logical eraseblock change operation is called using the %UBI_IOCEBCH
   * ioctl command of the corresponding UBI volume character device. A pointer to
   * a &struct ubi_leb_change_req object has to be passed to the ioctl. Then the
   * user is expected to write the requested amount of bytes (similarly to what
   * should be done in case of the "volume update" ioctl).
   *
   * Logical eraseblock map
   * ~~~~~~~~~~~~~~~~~~~~~
   *
   * To map a logical eraseblock to a physical eraseblock, the %UBI_IOCEBMAP
   * ioctl command should be used. A pointer to a &struct ubi_map_req object is
   * expected to be passed. The ioctl maps the requested logical eraseblock to
   * a physical eraseblock and returns.  Only non-mapped logical eraseblocks can
   * be mapped. If the logical eraseblock specified in the request is already
   * mapped to a physical eraseblock, the ioctl fails and returns error.
   *
   * Logical eraseblock unmap
   * ~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * To unmap a logical eraseblock to a physical eraseblock, the %UBI_IOCEBUNMAP
   * ioctl command should be used. The ioctl unmaps the logical eraseblocks,
   * schedules corresponding physical eraseblock for erasure, and returns. Unlike
   * the "LEB erase" command, it does not wait for the physical eraseblock being
   * erased. Note, the side effect of this is that if an unclean reboot happens
   * after the unmap ioctl returns, you may find the LEB mapped again to the same
   * physical eraseblock after the UBI is run again.
   *
   * Check if logical eraseblock is mapped
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * To check if a logical eraseblock is mapped to a physical eraseblock, the
   * %UBI_IOCEBISMAP ioctl command should be used. It returns %0 if the LEB is
   * not mapped, and %1 if it is mapped.
   *
   * Set an UBI volume property
   * ~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * To set an UBI volume property the %UBI_IOCSETPROP ioctl command should be
   * used. A pointer to a &struct ubi_set_vol_prop_req object is expected to be
   * passed. The object describes which property should be set, and to which value
   * it should be set.
   *
   * Block devices on UBI volumes
   * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   *
   * To create a R/O block device on top of an UBI volume the %UBI_IOCVOLCRBLK
   * should be used. A pointer to a &struct ubi_blkcreate_req object is expected
   * to be passed, which is not used and reserved for future usage.
   *
   * Conversely, to remove a block device the %UBI_IOCVOLRMBLK should be used,
   * which takes no arguments.
   */
  
  /*
   * When a new UBI volume or UBI device is created, users may either specify the
   * volume/device number they want to create or to let UBI automatically assign
   * the number using these constants.
   */
  #define UBI_VOL_NUM_AUTO (-1)
  #define UBI_DEV_NUM_AUTO (-1)
  
  /* Maximum volume name length */
  #define UBI_MAX_VOLUME_NAME 127
  
  /* ioctl commands of UBI character devices */
  
  #define UBI_IOC_MAGIC 'o'
  
  /* Create an UBI volume */
  #define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
  /* Remove an UBI volume */
  #define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, __s32)
  /* Re-size an UBI volume */
  #define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
  /* Re-name volumes */
  #define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
  
  /* ioctl commands of the UBI control character device */
  
  #define UBI_CTRL_IOC_MAGIC 'o'
  
  /* Attach an MTD device */
  #define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
  /* Detach an MTD device */
  #define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, __s32)
  
  /* ioctl commands of UBI volume character devices */
  
  #define UBI_VOL_IOC_MAGIC 'O'
  
  /* Start UBI volume update
   * Note: This actually takes a pointer (__s64*), but we can't change
   *       that without breaking the ABI on 32bit systems
   */
  #define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, __s64)
  /* LEB erasure command, used for debugging, disabled by default */
  #define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, __s32)
  /* Atomic LEB change command */
  #define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, __s32)
  /* Map LEB command */
  #define UBI_IOCEBMAP _IOW(UBI_VOL_IOC_MAGIC, 3, struct ubi_map_req)
  /* Unmap LEB command */
  #define UBI_IOCEBUNMAP _IOW(UBI_VOL_IOC_MAGIC, 4, __s32)
  /* Check if LEB is mapped command */
  #define UBI_IOCEBISMAP _IOR(UBI_VOL_IOC_MAGIC, 5, __s32)
  /* Set an UBI volume property */
  #define UBI_IOCSETVOLPROP _IOW(UBI_VOL_IOC_MAGIC, 6, \
  			       struct ubi_set_vol_prop_req)
  /* Create a R/O block device on top of an UBI volume */
  #define UBI_IOCVOLCRBLK _IOW(UBI_VOL_IOC_MAGIC, 7, struct ubi_blkcreate_req)
  /* Remove the R/O block device */
  #define UBI_IOCVOLRMBLK _IO(UBI_VOL_IOC_MAGIC, 8)
  
  /* Maximum MTD device name length supported by UBI */
  #define MAX_UBI_MTD_NAME_LEN 127
  
  /* Maximum amount of UBI volumes that can be re-named at one go */
  #define UBI_MAX_RNVOL 32
  
  /*
   * UBI volume type constants.
   *
   * @UBI_DYNAMIC_VOLUME: dynamic volume
   * @UBI_STATIC_VOLUME:  static volume
   */
  enum {
  	UBI_DYNAMIC_VOLUME = 3,
  	UBI_STATIC_VOLUME  = 4,
  };
  
  /*
   * UBI set volume property ioctl constants.
   *
   * @UBI_VOL_PROP_DIRECT_WRITE: allow (any non-zero value) or disallow (value 0)
   *                             user to directly write and erase individual
   *                             eraseblocks on dynamic volumes
   */
  enum {
  	UBI_VOL_PROP_DIRECT_WRITE = 1,
  };
  
  /**
   * struct ubi_attach_req - attach MTD device request.
   * @ubi_num: UBI device number to create
   * @mtd_num: MTD device number to attach
   * @vid_hdr_offset: VID header offset (use defaults if %0)
   * @max_beb_per1024: maximum expected number of bad PEB per 1024 PEBs
   * @padding: reserved for future, not used, has to be zeroed
   *
   * This data structure is used to specify MTD device UBI has to attach and the
   * parameters it has to use. The number which should be assigned to the new UBI
   * device is passed in @ubi_num. UBI may automatically assign the number if
   * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
   * @ubi_num.
   *
   * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
   * offset of the VID header within physical eraseblocks. The default offset is
   * the next min. I/O unit after the EC header. For example, it will be offset
   * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
   * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
   *
   * But in rare cases, if this optimizes things, the VID header may be placed to
   * a different offset. For example, the boot-loader might do things faster if
   * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
   * As the boot-loader would not normally need to read EC headers (unless it
   * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
   * example, but it real-life example. So, in this example, @vid_hdr_offer would
   * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
   * aligned, which is OK, as UBI is clever enough to realize this is 4th
   * sub-page of the first page and add needed padding.
   *
   * The @max_beb_per1024 is the maximum amount of bad PEBs UBI expects on the
   * UBI device per 1024 eraseblocks.  This value is often given in an other form
   * in the NAND datasheet (min NVB i.e. minimal number of valid blocks). The
   * maximum expected bad eraseblocks per 1024 is then:
   *    1024 * (1 - MinNVB / MaxNVB)
   * Which gives 20 for most NAND devices.  This limit is used in order to derive
   * amount of eraseblock UBI reserves for handling new bad blocks. If the device
   * has more bad eraseblocks than this limit, UBI does not reserve any physical
   * eraseblocks for new bad eraseblocks, but attempts to use available
   * eraseblocks (if any). The accepted range is 0-768. If 0 is given, the
   * default kernel value of %CONFIG_MTD_UBI_BEB_LIMIT will be used.
   */
  struct ubi_attach_req {
  	__s32 ubi_num;
  	__s32 mtd_num;
  	__s32 vid_hdr_offset;
  	__s16 max_beb_per1024;
  	__s8 padding[10];
  };
  
  /**
   * struct ubi_mkvol_req - volume description data structure used in
   *                        volume creation requests.
   * @vol_id: volume number
   * @alignment: volume alignment
   * @bytes: volume size in bytes
   * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
   * @padding1: reserved for future, not used, has to be zeroed
   * @name_len: volume name length
   * @padding2: reserved for future, not used, has to be zeroed
   * @name: volume name
   *
   * This structure is used by user-space programs when creating new volumes. The
   * @used_bytes field is only necessary when creating static volumes.
   *
   * The @alignment field specifies the required alignment of the volume logical
   * eraseblock. This means, that the size of logical eraseblocks will be aligned
   * to this number, i.e.,
   *	(UBI device logical eraseblock size) mod (@alignment) = 0.
   *
   * To put it differently, the logical eraseblock of this volume may be slightly
   * shortened in order to make it properly aligned. The alignment has to be
   * multiple of the flash minimal input/output unit, or %1 to utilize the entire
   * available space of logical eraseblocks.
   *
   * The @alignment field may be useful, for example, when one wants to maintain
   * a block device on top of an UBI volume. In this case, it is desirable to fit
   * an integer number of blocks in logical eraseblocks of this UBI volume. With
   * alignment it is possible to update this volume using plane UBI volume image
   * BLOBs, without caring about how to properly align them.
   */
  struct ubi_mkvol_req {
  	__s32 vol_id;
  	__s32 alignment;
  	__s64 bytes;
  	__s8 vol_type;
  	__s8 padding1;
  	__s16 name_len;
  	__s8 padding2[4];
  	char name[UBI_MAX_VOLUME_NAME + 1];
  } __packed;
  
  /**
   * struct ubi_rsvol_req - a data structure used in volume re-size requests.
   * @vol_id: ID of the volume to re-size
   * @bytes: new size of the volume in bytes
   *
   * Re-sizing is possible for both dynamic and static volumes. But while dynamic
   * volumes may be re-sized arbitrarily, static volumes cannot be made to be
   * smaller than the number of bytes they bear. To arbitrarily shrink a static
   * volume, it must be wiped out first (by means of volume update operation with
   * zero number of bytes).
   */
  struct ubi_rsvol_req {
  	__s64 bytes;
  	__s32 vol_id;
  } __packed;
  
  /**
   * struct ubi_rnvol_req - volumes re-name request.
   * @count: count of volumes to re-name
   * @padding1:  reserved for future, not used, has to be zeroed
   * @vol_id: ID of the volume to re-name
   * @name_len: name length
   * @padding2:  reserved for future, not used, has to be zeroed
   * @name: new volume name
   *
   * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
   * re-name is specified in the @count field. The ID of the volumes to re-name
   * and the new names are specified in the @vol_id and @name fields.
   *
   * The UBI volume re-name operation is atomic, which means that should power cut
   * happen, the volumes will have either old name or new name. So the possible
   * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
   * A and B one may create temporary volumes %A1 and %B1 with the new contents,
   * then atomically re-name A1->A and B1->B, in which case old %A and %B will
   * be removed.
   *
   * If it is not desirable to remove old A and B, the re-name request has to
   * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
   * become A and B, and old A and B will become A1 and B1.
   *
   * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
   * and B1 become A and B, and old A and B become X and Y.
   *
   * In other words, in case of re-naming into an existing volume name, the
   * existing volume is removed, unless it is re-named as well at the same
   * re-name request.
   */
  struct ubi_rnvol_req {
  	__s32 count;
  	__s8 padding1[12];
  	struct {
  		__s32 vol_id;
  		__s16 name_len;
  		__s8  padding2[2];
  		char    name[UBI_MAX_VOLUME_NAME + 1];
  	} ents[UBI_MAX_RNVOL];
  } __packed;
  
  /**
   * struct ubi_leb_change_req - a data structure used in atomic LEB change
   *                             requests.
   * @lnum: logical eraseblock number to change
   * @bytes: how many bytes will be written to the logical eraseblock
   * @dtype: pass "3" for better compatibility with old kernels
   * @padding: reserved for future, not used, has to be zeroed
   *
   * The @dtype field used to inform UBI about what kind of data will be written
   * to the LEB: long term (value 1), short term (value 2), unknown (value 3).
   * UBI tried to pick a PEB with lower erase counter for short term data and a
   * PEB with higher erase counter for long term data. But this was not really
   * used because users usually do not know this and could easily mislead UBI. We
   * removed this feature in May 2012. UBI currently just ignores the @dtype
   * field. But for better compatibility with older kernels it is recommended to
   * set @dtype to 3 (unknown).
   */
  struct ubi_leb_change_req {
  	__s32 lnum;
  	__s32 bytes;
  	__s8  dtype; /* obsolete, do not use! */
  	__s8  padding[7];
  } __packed;
  
  /**
   * struct ubi_map_req - a data structure used in map LEB requests.
   * @dtype: pass "3" for better compatibility with old kernels
   * @lnum: logical eraseblock number to unmap
   * @padding: reserved for future, not used, has to be zeroed
   */
  struct ubi_map_req {
  	__s32 lnum;
  	__s8  dtype; /* obsolete, do not use! */
  	__s8  padding[3];
  } __packed;
  
  
  /**
   * struct ubi_set_vol_prop_req - a data structure used to set an UBI volume
   *                               property.
   * @property: property to set (%UBI_VOL_PROP_DIRECT_WRITE)
   * @padding: reserved for future, not used, has to be zeroed
   * @value: value to set
   */
  struct ubi_set_vol_prop_req {
  	__u8  property;
  	__u8  padding[7];
  	__u64 value;
  }  __packed;
  
  /**
   * struct ubi_blkcreate_req - a data structure used in block creation requests.
   * @padding: reserved for future, not used, has to be zeroed
   */
  struct ubi_blkcreate_req {
  	__s8  padding[128];
  }  __packed;
  
  #endif /* __UBI_USER_H__ */