Current File : //usr/src/linux-headers-5.15.0-125-generic/include/linux/mtd/ubi.h
/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (c) International Business Machines Corp., 2006
*
* Author: Artem Bityutskiy (Битюцкий Артём)
*/
#ifndef __LINUX_UBI_H__
#define __LINUX_UBI_H__
#include <linux/ioctl.h>
#include <linux/types.h>
#include <linux/scatterlist.h>
#include <mtd/ubi-user.h>
/* All voumes/LEBs */
#define UBI_ALL -1
/*
* Maximum number of scatter gather list entries,
* we use only 64 to have a lower memory foot print.
*/
#define UBI_MAX_SG_COUNT 64
/*
* enum ubi_open_mode - UBI volume open mode constants.
*
* UBI_READONLY: read-only mode
* UBI_READWRITE: read-write mode
* UBI_EXCLUSIVE: exclusive mode
* UBI_METAONLY: modify only the volume meta-data,
* i.e. the data stored in the volume table, but not in any of volume LEBs.
*/
enum {
UBI_READONLY = 1,
UBI_READWRITE,
UBI_EXCLUSIVE,
UBI_METAONLY
};
/**
* struct ubi_volume_info - UBI volume description data structure.
* @vol_id: volume ID
* @ubi_num: UBI device number this volume belongs to
* @size: how many physical eraseblocks are reserved for this volume
* @used_bytes: how many bytes of data this volume contains
* @used_ebs: how many physical eraseblocks of this volume actually contain any
* data
* @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
* @corrupted: non-zero if the volume is corrupted (static volumes only)
* @upd_marker: non-zero if the volume has update marker set
* @alignment: volume alignment
* @usable_leb_size: how many bytes are available in logical eraseblocks of
* this volume
* @name_len: volume name length
* @name: volume name
* @cdev: UBI volume character device major and minor numbers
*
* The @corrupted flag is only relevant to static volumes and is always zero
* for dynamic ones. This is because UBI does not care about dynamic volume
* data protection and only cares about protecting static volume data.
*
* The @upd_marker flag is set if the volume update operation was interrupted.
* Before touching the volume data during the update operation, UBI first sets
* the update marker flag for this volume. If the volume update operation was
* further interrupted, the update marker indicates this. If the update marker
* is set, the contents of the volume is certainly damaged and a new volume
* update operation has to be started.
*
* To put it differently, @corrupted and @upd_marker fields have different
* semantics:
* o the @corrupted flag means that this static volume is corrupted for some
* reasons, but not because an interrupted volume update
* o the @upd_marker field means that the volume is damaged because of an
* interrupted update operation.
*
* I.e., the @corrupted flag is never set if the @upd_marker flag is set.
*
* The @used_bytes and @used_ebs fields are only really needed for static
* volumes and contain the number of bytes stored in this static volume and how
* many eraseblock this data occupies. In case of dynamic volumes, the
* @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
* field is equivalent to @size.
*
* In general, logical eraseblock size is a property of the UBI device, not
* of the UBI volume. Indeed, the logical eraseblock size depends on the
* physical eraseblock size and on how much bytes UBI headers consume. But
* because of the volume alignment (@alignment), the usable size of logical
* eraseblocks if a volume may be less. The following equation is true:
* @usable_leb_size = LEB size - (LEB size mod @alignment),
* where LEB size is the logical eraseblock size defined by the UBI device.
*
* The alignment is multiple to the minimal flash input/output unit size or %1
* if all the available space is used.
*
* To put this differently, alignment may be considered is a way to change
* volume logical eraseblock sizes.
*/
struct ubi_volume_info {
int ubi_num;
int vol_id;
int size;
long long used_bytes;
int used_ebs;
int vol_type;
int corrupted;
int upd_marker;
int alignment;
int usable_leb_size;
int name_len;
const char *name;
dev_t cdev;
};
/**
* struct ubi_sgl - UBI scatter gather list data structure.
* @list_pos: current position in @sg[]
* @page_pos: current position in @sg[@list_pos]
* @sg: the scatter gather list itself
*
* ubi_sgl is a wrapper around a scatter list which keeps track of the
* current position in the list and the current list item such that
* it can be used across multiple ubi_leb_read_sg() calls.
*/
struct ubi_sgl {
int list_pos;
int page_pos;
struct scatterlist sg[UBI_MAX_SG_COUNT];
};
/**
* ubi_sgl_init - initialize an UBI scatter gather list data structure.
* @usgl: the UBI scatter gather struct itself
*
* Please note that you still have to use sg_init_table() or any adequate
* function to initialize the unterlaying struct scatterlist.
*/
static inline void ubi_sgl_init(struct ubi_sgl *usgl)
{
usgl->list_pos = 0;
usgl->page_pos = 0;
}
/**
* struct ubi_device_info - UBI device description data structure.
* @ubi_num: ubi device number
* @leb_size: logical eraseblock size on this UBI device
* @leb_start: starting offset of logical eraseblocks within physical
* eraseblocks
* @min_io_size: minimal I/O unit size
* @max_write_size: maximum amount of bytes the underlying flash can write at a
* time (MTD write buffer size)
* @ro_mode: if this device is in read-only mode
* @cdev: UBI character device major and minor numbers
*
* Note, @leb_size is the logical eraseblock size offered by the UBI device.
* Volumes of this UBI device may have smaller logical eraseblock size if their
* alignment is not equivalent to %1.
*
* The @max_write_size field describes flash write maximum write unit. For
* example, NOR flash allows for changing individual bytes, so @min_io_size is
* %1. However, it does not mean than NOR flash has to write data byte-by-byte.
* Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
* writing large chunks of data, they write 64-bytes at a time. Obviously, this
* improves write throughput.
*
* Also, the MTD device may have N interleaved (striped) flash chips
* underneath, in which case @min_io_size can be physical min. I/O size of
* single flash chip, while @max_write_size can be N * @min_io_size.
*
* The @max_write_size field is always greater or equivalent to @min_io_size.
* E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
* contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
* page size.
*/
struct ubi_device_info {
int ubi_num;
int leb_size;
int leb_start;
int min_io_size;
int max_write_size;
int ro_mode;
dev_t cdev;
};
/*
* Volume notification types.
* @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
* volume was created)
* @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
* or a volume was removed)
* @UBI_VOLUME_RESIZED: a volume has been re-sized
* @UBI_VOLUME_RENAMED: a volume has been re-named
* @UBI_VOLUME_UPDATED: data has been written to a volume
*
* These constants define which type of event has happened when a volume
* notification function is invoked.
*/
enum {
UBI_VOLUME_ADDED,
UBI_VOLUME_REMOVED,
UBI_VOLUME_RESIZED,
UBI_VOLUME_RENAMED,
UBI_VOLUME_UPDATED,
};
/*
* struct ubi_notification - UBI notification description structure.
* @di: UBI device description object
* @vi: UBI volume description object
*
* UBI notifiers are called with a pointer to an object of this type. The
* object describes the notification. Namely, it provides a description of the
* UBI device and UBI volume the notification informs about.
*/
struct ubi_notification {
struct ubi_device_info di;
struct ubi_volume_info vi;
};
/* UBI descriptor given to users when they open UBI volumes */
struct ubi_volume_desc;
int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
void ubi_get_volume_info(struct ubi_volume_desc *desc,
struct ubi_volume_info *vi);
struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
int mode);
struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
int ubi_register_volume_notifier(struct notifier_block *nb,
int ignore_existing);
int ubi_unregister_volume_notifier(struct notifier_block *nb);
void ubi_close_volume(struct ubi_volume_desc *desc);
int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
int len, int check);
int ubi_leb_read_sg(struct ubi_volume_desc *desc, int lnum, struct ubi_sgl *sgl,
int offset, int len, int check);
int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
int offset, int len);
int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
int len);
int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
int ubi_sync(int ubi_num);
int ubi_flush(int ubi_num, int vol_id, int lnum);
/*
* This function is the same as the 'ubi_leb_read()' function, but it does not
* provide the checking capability.
*/
static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
int offset, int len)
{
return ubi_leb_read(desc, lnum, buf, offset, len, 0);
}
/*
* This function is the same as the 'ubi_leb_read_sg()' function, but it does
* not provide the checking capability.
*/
static inline int ubi_read_sg(struct ubi_volume_desc *desc, int lnum,
struct ubi_sgl *sgl, int offset, int len)
{
return ubi_leb_read_sg(desc, lnum, sgl, offset, len, 0);
}
#endif /* !__LINUX_UBI_H__ */
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