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![Richard Weinberger](/assets/img/avatar_default.png)
Adds a new set of functions to deal with scatter gather. ubi_eba_read_leb_sg() will read from a LEB into a scatter gather list. The new data structure struct ubi_sgl will be used within UBI to hold the scatter gather list itself and metadata to have a cursor within the list. Signed-off-by: Richard Weinberger <richard@nod.at> Tested-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar> Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
284 lines
10 KiB
C
284 lines
10 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 __LINUX_UBI_H__
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#define __LINUX_UBI_H__
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#include <linux/ioctl.h>
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#include <linux/types.h>
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#include <linux/scatterlist.h>
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#include <mtd/ubi-user.h>
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/* All voumes/LEBs */
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#define UBI_ALL -1
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/*
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* Maximum number of scatter gather list entries,
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* we use only 64 to have a lower memory foot print.
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*/
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#define UBI_MAX_SG_COUNT 64
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/*
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* enum ubi_open_mode - UBI volume open mode constants.
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*
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* UBI_READONLY: read-only mode
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* UBI_READWRITE: read-write mode
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* UBI_EXCLUSIVE: exclusive mode
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* UBI_METAONLY: modify only the volume meta-data,
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* i.e. the data stored in the volume table, but not in any of volume LEBs.
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*/
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enum {
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UBI_READONLY = 1,
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UBI_READWRITE,
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UBI_EXCLUSIVE,
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UBI_METAONLY
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};
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/**
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* struct ubi_volume_info - UBI volume description data structure.
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* @vol_id: volume ID
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* @ubi_num: UBI device number this volume belongs to
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* @size: how many physical eraseblocks are reserved for this volume
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* @used_bytes: how many bytes of data this volume contains
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* @used_ebs: how many physical eraseblocks of this volume actually contain any
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* data
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* @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
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* @corrupted: non-zero if the volume is corrupted (static volumes only)
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* @upd_marker: non-zero if the volume has update marker set
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* @alignment: volume alignment
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* @usable_leb_size: how many bytes are available in logical eraseblocks of
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* this volume
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* @name_len: volume name length
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* @name: volume name
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* @cdev: UBI volume character device major and minor numbers
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*
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* The @corrupted flag is only relevant to static volumes and is always zero
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* for dynamic ones. This is because UBI does not care about dynamic volume
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* data protection and only cares about protecting static volume data.
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*
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* The @upd_marker flag is set if the volume update operation was interrupted.
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* Before touching the volume data during the update operation, UBI first sets
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* the update marker flag for this volume. If the volume update operation was
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* further interrupted, the update marker indicates this. If the update marker
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* is set, the contents of the volume is certainly damaged and a new volume
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* update operation has to be started.
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*
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* To put it differently, @corrupted and @upd_marker fields have different
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* semantics:
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* o the @corrupted flag means that this static volume is corrupted for some
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* reasons, but not because an interrupted volume update
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* o the @upd_marker field means that the volume is damaged because of an
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* interrupted update operation.
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*
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* I.e., the @corrupted flag is never set if the @upd_marker flag is set.
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*
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* The @used_bytes and @used_ebs fields are only really needed for static
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* volumes and contain the number of bytes stored in this static volume and how
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* many eraseblock this data occupies. In case of dynamic volumes, the
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* @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
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* field is equivalent to @size.
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*
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* In general, logical eraseblock size is a property of the UBI device, not
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* of the UBI volume. Indeed, the logical eraseblock size depends on the
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* physical eraseblock size and on how much bytes UBI headers consume. But
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* because of the volume alignment (@alignment), the usable size of logical
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* eraseblocks if a volume may be less. The following equation is true:
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* @usable_leb_size = LEB size - (LEB size mod @alignment),
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* where LEB size is the logical eraseblock size defined by the UBI device.
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*
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* The alignment is multiple to the minimal flash input/output unit size or %1
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* if all the available space is used.
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*
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* To put this differently, alignment may be considered is a way to change
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* volume logical eraseblock sizes.
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*/
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struct ubi_volume_info {
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int ubi_num;
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int vol_id;
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int size;
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long long used_bytes;
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int used_ebs;
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int vol_type;
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int corrupted;
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int upd_marker;
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int alignment;
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int usable_leb_size;
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int name_len;
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const char *name;
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dev_t cdev;
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};
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/**
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* struct ubi_sgl - UBI scatter gather list data structure.
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* @list_pos: current position in @sg[]
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* @page_pos: current position in @sg[@list_pos]
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* @sg: the scatter gather list itself
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*
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* ubi_sgl is a wrapper around a scatter list which keeps track of the
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* current position in the list and the current list item such that
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* it can be used across multiple ubi_leb_read_sg() calls.
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*/
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struct ubi_sgl {
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int list_pos;
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int page_pos;
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struct scatterlist sg[UBI_MAX_SG_COUNT];
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};
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/**
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* ubi_sgl_init - initialize an UBI scatter gather list data structure.
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* @usgl: the UBI scatter gather struct itself
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*
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* Please note that you still have to use sg_init_table() or any adequate
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* function to initialize the unterlaying struct scatterlist.
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*/
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static inline void ubi_sgl_init(struct ubi_sgl *usgl)
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{
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usgl->list_pos = 0;
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usgl->page_pos = 0;
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}
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/**
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* struct ubi_device_info - UBI device description data structure.
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* @ubi_num: ubi device number
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* @leb_size: logical eraseblock size on this UBI device
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* @leb_start: starting offset of logical eraseblocks within physical
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* eraseblocks
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* @min_io_size: minimal I/O unit size
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* @max_write_size: maximum amount of bytes the underlying flash can write at a
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* time (MTD write buffer size)
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* @ro_mode: if this device is in read-only mode
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* @cdev: UBI character device major and minor numbers
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*
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* Note, @leb_size is the logical eraseblock size offered by the UBI device.
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* Volumes of this UBI device may have smaller logical eraseblock size if their
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* alignment is not equivalent to %1.
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*
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* The @max_write_size field describes flash write maximum write unit. For
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* example, NOR flash allows for changing individual bytes, so @min_io_size is
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* %1. However, it does not mean than NOR flash has to write data byte-by-byte.
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* Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
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* writing large chunks of data, they write 64-bytes at a time. Obviously, this
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* improves write throughput.
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*
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* Also, the MTD device may have N interleaved (striped) flash chips
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* underneath, in which case @min_io_size can be physical min. I/O size of
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* single flash chip, while @max_write_size can be N * @min_io_size.
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*
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* The @max_write_size field is always greater or equivalent to @min_io_size.
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* E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
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* contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
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* page size.
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*/
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struct ubi_device_info {
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int ubi_num;
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int leb_size;
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int leb_start;
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int min_io_size;
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int max_write_size;
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int ro_mode;
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dev_t cdev;
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};
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/*
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* Volume notification types.
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* @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
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* volume was created)
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* @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
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* or a volume was removed)
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* @UBI_VOLUME_RESIZED: a volume has been re-sized
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* @UBI_VOLUME_RENAMED: a volume has been re-named
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* @UBI_VOLUME_UPDATED: data has been written to a volume
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*
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* These constants define which type of event has happened when a volume
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* notification function is invoked.
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*/
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enum {
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UBI_VOLUME_ADDED,
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UBI_VOLUME_REMOVED,
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UBI_VOLUME_RESIZED,
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UBI_VOLUME_RENAMED,
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UBI_VOLUME_UPDATED,
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};
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/*
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* struct ubi_notification - UBI notification description structure.
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* @di: UBI device description object
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* @vi: UBI volume description object
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*
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* UBI notifiers are called with a pointer to an object of this type. The
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* object describes the notification. Namely, it provides a description of the
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* UBI device and UBI volume the notification informs about.
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*/
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struct ubi_notification {
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struct ubi_device_info di;
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struct ubi_volume_info vi;
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};
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/* UBI descriptor given to users when they open UBI volumes */
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struct ubi_volume_desc;
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int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
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void ubi_get_volume_info(struct ubi_volume_desc *desc,
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struct ubi_volume_info *vi);
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struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
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struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
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int mode);
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struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
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int ubi_register_volume_notifier(struct notifier_block *nb,
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int ignore_existing);
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int ubi_unregister_volume_notifier(struct notifier_block *nb);
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void ubi_close_volume(struct ubi_volume_desc *desc);
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int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
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int len, int check);
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int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
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int offset, int len, int check);
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int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
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int offset, int len);
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int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
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int len);
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int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
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int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
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int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
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int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
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int ubi_sync(int ubi_num);
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int ubi_flush(int ubi_num, int vol_id, int lnum);
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/*
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* This function is the same as the 'ubi_leb_read()' function, but it does not
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* provide the checking capability.
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*/
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static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
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int offset, int len)
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{
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return ubi_leb_read(desc, lnum, buf, offset, len, 0);
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}
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/*
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* This function is the same as the 'ubi_leb_read_sg()' function, but it does
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* not provide the checking capability.
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*/
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static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
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struct ubi_sgl *sgl, int offset, int len)
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{
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return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
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}
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#endif /* !__LINUX_UBI_H__ */
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