forked from luck/tmp_suning_uos_patched
f40ac9cdf6
Quite useful ioctl which allows to make atomic system upgrades. The idea belongs to Richard Titmuss <richard_titmuss@logitech.com> Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
323 lines
12 KiB
C
323 lines
12 KiB
C
/*
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* Copyright (c) International Business Machines Corp., 2006
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* Author: Artem Bityutskiy (Битюцкий Артём)
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*/
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#ifndef __UBI_USER_H__
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#define __UBI_USER_H__
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/*
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* UBI device creation (the same as MTD device attachment)
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
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* control device. The caller has to properly fill and pass
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* &struct ubi_attach_req object - UBI will attach the MTD device specified in
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* the request and return the newly created UBI device number as the ioctl
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* return value.
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*
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* UBI device deletion (the same as MTD device detachment)
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* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
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* control device.
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*
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* UBI volume creation
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* ~~~~~~~~~~~~~~~~~~~
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*
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* UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character
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* device. A &struct ubi_mkvol_req object has to be properly filled and a
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* pointer to it has to be passed to the IOCTL.
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*
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* UBI volume deletion
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* ~~~~~~~~~~~~~~~~~~~
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*
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* To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character
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* device should be used. A pointer to the 32-bit volume ID hast to be passed
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* to the IOCTL.
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*
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* UBI volume re-size
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* ~~~~~~~~~~~~~~~~~~
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*
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* To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character
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* device should be used. A &struct ubi_rsvol_req object has to be properly
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* filled and a pointer to it has to be passed to the IOCTL.
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*
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* UBI volumes re-name
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* ~~~~~~~~~~~~~~~~~~~
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*
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* To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
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* of the UBI character device should be used. A &struct ubi_rnvol_req object
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* has to be properly filled and a pointer to it has to be passed to the IOCTL.
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*
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* UBI volume update
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* ~~~~~~~~~~~~~~~~~
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*
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* Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
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* corresponding UBI volume character device. A pointer to a 64-bit update
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* size should be passed to the IOCTL. After this, UBI expects user to write
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* this number of bytes to the volume character device. The update is finished
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* when the claimed number of bytes is passed. So, the volume update sequence
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* is something like:
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*
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* fd = open("/dev/my_volume");
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* ioctl(fd, UBI_IOCVOLUP, &image_size);
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* write(fd, buf, image_size);
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* close(fd);
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*
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* Atomic eraseblock change
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* ~~~~~~~~~~~~~~~~~~~~~~~~
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*
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* Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
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* command of the corresponding UBI volume character device. A pointer to
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* &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
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* expected to write the requested amount of bytes. This is similar to the
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* "volume update" IOCTL.
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*/
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/*
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* When a new UBI volume or UBI device is created, users may either specify the
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* volume/device number they want to create or to let UBI automatically assign
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* the number using these constants.
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*/
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#define UBI_VOL_NUM_AUTO (-1)
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#define UBI_DEV_NUM_AUTO (-1)
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/* Maximum volume name length */
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#define UBI_MAX_VOLUME_NAME 127
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/* IOCTL commands of UBI character devices */
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#define UBI_IOC_MAGIC 'o'
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/* Create an UBI volume */
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#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
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/* Remove an UBI volume */
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#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
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/* Re-size an UBI volume */
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#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
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/* Re-name volumes */
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#define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)
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/* IOCTL commands of the UBI control character device */
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#define UBI_CTRL_IOC_MAGIC 'o'
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/* Attach an MTD device */
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#define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
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/* Detach an MTD device */
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#define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)
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/* IOCTL commands of UBI volume character devices */
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#define UBI_VOL_IOC_MAGIC 'O'
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/* Start UBI volume update */
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#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
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/* An eraseblock erasure command, used for debugging, disabled by default */
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#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
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/* An atomic eraseblock change command */
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#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)
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/* Maximum MTD device name length supported by UBI */
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#define MAX_UBI_MTD_NAME_LEN 127
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/* Maximum amount of UBI volumes that can be re-named at one go */
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#define UBI_MAX_RNVOL 32
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/*
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* UBI data type hint constants.
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*
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* UBI_LONGTERM: long-term data
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* UBI_SHORTTERM: short-term data
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* UBI_UNKNOWN: data persistence is unknown
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*
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* These constants are used when data is written to UBI volumes in order to
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* help the UBI wear-leveling unit to find more appropriate physical
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* eraseblocks.
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*/
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enum {
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UBI_LONGTERM = 1,
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UBI_SHORTTERM = 2,
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UBI_UNKNOWN = 3,
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};
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/*
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* UBI volume type constants.
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*
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* @UBI_DYNAMIC_VOLUME: dynamic volume
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* @UBI_STATIC_VOLUME: static volume
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*/
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enum {
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UBI_DYNAMIC_VOLUME = 3,
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UBI_STATIC_VOLUME = 4,
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};
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/**
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* struct ubi_attach_req - attach MTD device request.
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* @ubi_num: UBI device number to create
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* @mtd_num: MTD device number to attach
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* @vid_hdr_offset: VID header offset (use defaults if %0)
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* @padding: reserved for future, not used, has to be zeroed
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*
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* This data structure is used to specify MTD device UBI has to attach and the
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* parameters it has to use. The number which should be assigned to the new UBI
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* device is passed in @ubi_num. UBI may automatically assign the number if
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* @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
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* @ubi_num.
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*
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* Most applications should pass %0 in @vid_hdr_offset to make UBI use default
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* offset of the VID header within physical eraseblocks. The default offset is
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* the next min. I/O unit after the EC header. For example, it will be offset
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* 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
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* it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
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*
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* But in rare cases, if this optimizes things, the VID header may be placed to
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* a different offset. For example, the boot-loader might do things faster if the
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* VID header sits at the end of the first 2KiB NAND page with 4 sub-pages. As
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* the boot-loader would not normally need to read EC headers (unless it needs
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* UBI in RW mode), it might be faster to calculate ECC. This is weird example,
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* but it real-life example. So, in this example, @vid_hdr_offer would be
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* 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
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* aligned, which is OK, as UBI is clever enough to realize this is 4th sub-page
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* of the first page and add needed padding.
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*/
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struct ubi_attach_req {
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int32_t ubi_num;
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int32_t mtd_num;
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int32_t vid_hdr_offset;
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int8_t padding[12];
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};
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/**
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* struct ubi_mkvol_req - volume description data structure used in
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* volume creation requests.
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* @vol_id: volume number
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* @alignment: volume alignment
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* @bytes: volume size in bytes
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* @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
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* @padding1: reserved for future, not used, has to be zeroed
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* @name_len: volume name length
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* @padding2: reserved for future, not used, has to be zeroed
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* @name: volume name
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*
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* This structure is used by user-space programs when creating new volumes. The
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* @used_bytes field is only necessary when creating static volumes.
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*
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* The @alignment field specifies the required alignment of the volume logical
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* eraseblock. This means, that the size of logical eraseblocks will be aligned
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* to this number, i.e.,
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* (UBI device logical eraseblock size) mod (@alignment) = 0.
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*
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* To put it differently, the logical eraseblock of this volume may be slightly
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* shortened in order to make it properly aligned. The alignment has to be
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* multiple of the flash minimal input/output unit, or %1 to utilize the entire
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* available space of logical eraseblocks.
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*
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* The @alignment field may be useful, for example, when one wants to maintain
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* a block device on top of an UBI volume. In this case, it is desirable to fit
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* an integer number of blocks in logical eraseblocks of this UBI volume. With
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* alignment it is possible to update this volume using plane UBI volume image
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* BLOBs, without caring about how to properly align them.
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*/
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struct ubi_mkvol_req {
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int32_t vol_id;
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int32_t alignment;
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int64_t bytes;
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int8_t vol_type;
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int8_t padding1;
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int16_t name_len;
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int8_t padding2[4];
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char name[UBI_MAX_VOLUME_NAME + 1];
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} __attribute__ ((packed));
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/**
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* struct ubi_rsvol_req - a data structure used in volume re-size requests.
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* @vol_id: ID of the volume to re-size
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* @bytes: new size of the volume in bytes
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*
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* Re-sizing is possible for both dynamic and static volumes. But while dynamic
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* volumes may be re-sized arbitrarily, static volumes cannot be made to be
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* smaller then the number of bytes they bear. To arbitrarily shrink a static
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* volume, it must be wiped out first (by means of volume update operation with
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* zero number of bytes).
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*/
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struct ubi_rsvol_req {
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int64_t bytes;
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int32_t vol_id;
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} __attribute__ ((packed));
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/**
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* struct ubi_rnvol_req - volumes re-name request.
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* @count: count of volumes to re-name
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* @padding1: reserved for future, not used, has to be zeroed
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* @vol_id: ID of the volume to re-name
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* @name_len: name length
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* @padding2: reserved for future, not used, has to be zeroed
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* @name: new volume name
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*
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* UBI allows to re-name up to %32 volumes at one go. The count of volumes to
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* re-name is specified in the @count field. The ID of the volumes to re-name
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* and the new names are specified in the @vol_id and @name fields.
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*
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* The UBI volume re-name operation is atomic, which means that should power cut
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* happen, the volumes will have either old name or new name. So the possible
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* use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
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* A and B one may create temporary volumes %A1 and %B1 with the new contents,
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* then atomically re-name A1->A and B1->B, in which case old %A and %B will
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* be removed.
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*
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* If it is not desirable to remove old A and B, the re-name request has to
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* contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
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* become A and B, and old A and B will become A1 and B1.
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*
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* It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
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* and B1 become A and B, and old A and B become X and Y.
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*
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* In other words, in case of re-naming into an existing volume name, the
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* existing volume is removed, unless it is re-named as well at the same
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* re-name request.
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*/
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struct ubi_rnvol_req {
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int32_t count;
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int8_t padding1[12];
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struct {
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int32_t vol_id;
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int16_t name_len;
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int8_t padding2[2];
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char name[UBI_MAX_VOLUME_NAME + 1];
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} ents[UBI_MAX_RNVOL];
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} __attribute__ ((packed));
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/**
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* struct ubi_leb_change_req - a data structure used in atomic logical
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* eraseblock change requests.
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* @lnum: logical eraseblock number to change
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* @bytes: how many bytes will be written to the logical eraseblock
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* @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
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* @padding: reserved for future, not used, has to be zeroed
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*/
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struct ubi_leb_change_req {
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int32_t lnum;
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int32_t bytes;
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int8_t dtype;
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int8_t padding[7];
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} __attribute__ ((packed));
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#endif /* __UBI_USER_H__ */
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