path: root/drivers/mtd/ubi/ubi.h

/*
 * Copyright (c) International Business Machines Corp., 2006
 * Copyright (c) Nokia Corporation, 2006, 2007
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
 * the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Artem Bityutskiy (Битюцкий Артём)
 */

#ifndef __UBI_UBI_H__
#define __UBI_UBI_H__

#include <linux/init.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#include <linux/rwsem.h>
#include <linux/spinlock.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/notifier.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/ubi.h>
#include <asm/pgtable.h>

#include "ubi-media.h"

/* Maximum number of supported UBI devices */
#define UBI_MAX_DEVICES 32

/* UBI name used for character devices, sysfs, etc */
#define UBI_NAME_STR "ubi"

/* Normal UBI messages */
#define ubi_msg(fmt, ...) pr_notice("UBI: " fmt "\n", ##__VA_ARGS__)
/* UBI warning messages */
#define ubi_warn(fmt, ...) pr_warn("UBI warning: %s: " fmt "\n",  \
				   __func__, ##__VA_ARGS__)
/* UBI error messages */
#define ubi_err(fmt, ...) pr_err("UBI error: %s: " fmt "\n",      \
				 __func__, ##__VA_ARGS__)

/* Background thread name pattern */
#define UBI_BGT_NAME_PATTERN "ubi_bgt%dd"

/*
 * This marker in the EBA table means that the LEB is um-mapped.
 * NOTE! It has to have the same value as %UBI_ALL.
 */
#define UBI_LEB_UNMAPPED -1

/*
 * In case of errors, UBI tries to repeat the operation several times before
 * returning error. The below constant defines how many times UBI re-tries.
 */
#define UBI_IO_RETRIES 3

/*
 * Length of the protection queue. The length is effectively equivalent to the
 * number of (global) erase cycles PEBs are protected from the wear-leveling
 * worker.
 */
#define UBI_PROT_QUEUE_LEN 10

/* The volume ID/LEB number/erase counter is unknown */
#define UBI_UNKNOWN -1

/*
 * The UBI debugfs directory name pattern and maximum name length (3 for "ubi"
 * + 2 for the number plus 1 for the trailing zero byte.
 */
#define UBI_DFS_DIR_NAME "ubi%d"
#define UBI_DFS_DIR_LEN  (3 + 2 + 1)

/*
 * Error codes returned by the I/O sub-system.
 *
 * UBI_IO_FF: the read region of flash contains only 0xFFs
 * UBI_IO_FF_BITFLIPS: the same as %UBI_IO_FF, but also also there was a data
 *                     integrity error reported by the MTD driver
 *                     (uncorrectable ECC error in case of NAND)
 * UBI_IO_BAD_HDR: the EC or VID header is corrupted (bad magic or CRC)
 * UBI_IO_BAD_HDR_EBADMSG: the same as %UBI_IO_BAD_HDR, but also there was a
 *                         data integrity error reported by the MTD driver
 *                         (uncorrectable ECC error in case of NAND)
 * UBI_IO_BITFLIPS: bit-flips were detected and corrected
 *
 * Note, it is probably better to have bit-flip and ebadmsg as flags which can
 * be or'ed with other error code. But this is a big change because there are
 * may callers, so it does not worth the risk of introducing a bug
 */
enum {
	UBI_IO_FF = 1,
	UBI_IO_FF_BITFLIPS,
	UBI_IO_BAD_HDR,
	UBI_IO_BAD_HDR_EBADMSG,
	UBI_IO_BITFLIPS,
};

/*
 * Return codes of the 'ubi_eba_copy_leb()' function.
 *
 * MOVE_CANCEL_RACE: canceled because the volume is being deleted, the source
 *                   PEB was put meanwhile, or there is I/O on the source PEB
 * MOVE_SOURCE_RD_ERR: canceled because there was a read error from the source
 *                     PEB
 * MOVE_TARGET_RD_ERR: canceled because there was a read error from the target
 *                     PEB
 * MOVE_TARGET_WR_ERR: canceled because there was a write error to the target
 *                     PEB
 * MOVE_TARGET_BITFLIPS: canceled because a bit-flip was detected in the
 *                       target PEB
 * MOVE_RETRY: retry scrubbing the PEB
 */
enum {
	MOVE_CANCEL_RACE = 1,
	MOVE_SOURCE_RD_ERR,
	MOVE_TARGET_RD_ERR,
	MOVE_TARGET_WR_ERR,
	MOVE_TARGET_BITFLIPS,
	MOVE_RETRY,
};

/*
 * Return codes of the fastmap sub-system
 *
 * UBI_NO_FASTMAP: No fastmap super block was found
 * UBI_BAD_FASTMAP: A fastmap was found but it's unusable
 */
enum {
	UBI_NO_FASTMAP = 1,
	UBI_BAD_FASTMAP,
};

/**
 * struct ubi_wl_entry - wear-leveling entry.
 * @u.rb: link in the corresponding (free/used) RB-tree
 * @u.list: link in the protection queue
 * @ec: erase counter
 * @pnum: physical eraseblock number
 *
 * This data structure is used in the WL sub-system. Each physical eraseblock
 * has a corresponding &struct wl_entry object which may be kept in different
 * RB-trees. See WL sub-system for details.
 */
struct ubi_wl_entry {
	union {
		struct rb_node rb;
		struct list_head list;
	} u;
	int ec;
	int pnum;
};

/**
 * struct ubi_ltree_entry - an entry in the lock tree.
 * @rb: links RB-tree nodes
 * @vol_id: volume ID of the locked logical eraseblock
 * @lnum: locked logical eraseblock number
 * @users: how many tasks are using this logical eraseblock or wait for it
 * @mutex: read/write mutex to implement read/write access serialization to
 *         the (@vol_id, @lnum) logical eraseblock
 *
 * This data structure is used in the EBA sub-system to implement per-LEB
 * locking. When a logical eraseblock is being locked - corresponding
 * &struct ubi_ltree_entry object is inserted to the lock tree (@ubi->ltree).
 * See EBA sub-system for details.
 */
struct ubi_ltree_entry {
	struct rb_node rb;
	int vol_id;
	int lnum;
	int users;
	struct rw_semaphore mutex;
};

/**
 * struct ubi_rename_entry - volume re-name description data structure.
 * @new_name_len: new volume name length
 * @new_name: new volume name
 * @remove: if not zero, this volume should be removed, not re-named
 * @desc: descriptor of the volume
 * @list: links re-name entries into a list
 *
 * This data structure is utilized in the multiple volume re-name code. Namely,
 * UBI first creates a list of &struct ubi_rename_entry objects from the
 * &struct ubi_rnvol_req request object, and then utilizes this list to do all
 * the job.
 */
struct ubi_rename_entry {
	int new_name_len;
	char new_name[UBI_VOL_NAME_MAX + 1];
	int remove;
	struct ubi_volume_desc *desc;
	struct list_head list;
};

struct ubi_volume_desc;

/**
 * struct ubi_fastmap_layout - in-memory fastmap data structure.
 * @e: PEBs used by the current fastmap
 * @to_be_tortured: if non-zero tortured this PEB
 * @used_blocks: number of used PEBs
 * @max_pool_size: maximal size of the user pool
 * @max_wl_pool_size: maximal size of the pool used by the WL sub-system
 */
struct ubi_fastmap_layout {
	struct ubi_wl_entry *e[UBI_FM_MAX_BLOCKS];
	int to_be_tortured[UBI_FM_MAX_BLOCKS];
	int used_blocks;
	int max_pool_size;
	int max_wl_pool_size;
};

/**
 * struct ubi_fm_pool - in-memory fastmap pool
 * @pebs: PEBs in this pool
 * @used: number of used PEBs
 * @size: total number of PEBs in this pool
 * @max_size: maximal size of the pool
 *
 * A pool gets filled with up to max_size.
 * If all PEBs within the pool are used a new fastmap will be written
 * to the flash and the pool gets refilled with empty PEBs.
 *
 */
struct ubi_fm_pool {
	int pebs[UBI_FM_MAX_POOL_SIZE];
	int used;
	int size;
	int max_size;
};

/**
 * struct ubi_volume - UBI volume description data structure.
 * @dev: device object to make use of the the Linux device model
 * @cdev: character device object to create character device
 * @ubi: reference to the UBI device description object
 * @vol_id: volume ID
 * @ref_count: volume reference count
 * @readers: number of users holding this volume in read-only mode
 * @writers: number of users holding this volume in read-write mode
 * @exclusive: whether somebody holds this volume in exclusive mode
 *
 * @reserved_pebs: how many physical eraseblocks are reserved for this volume
 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 * @usable_leb_size: logical eraseblock size without padding
 * @used_ebs: how many logical eraseblocks in this volume contain data
 * @last_eb_bytes: how many bytes are stored in the last logical eraseblock
 * @used_bytes: how many bytes of data this volume contains
 * @alignment: volume alignment
 * @data_pad: how many bytes are not used at the end of physical eraseblocks to
 *            satisfy the requested alignment
 * @name_len: volume name length
 * @name: volume name
 *
 * @upd_ebs: how many eraseblocks are expected to be updated
 * @ch_lnum: LEB number which is being changing by the atomic LEB change
 *           operation
 * @upd_bytes: how many bytes are expected to be received for volume update or
 *             atomic LEB change
 * @upd_received: how many bytes were already received for volume update or
 *                atomic LEB change
 * @upd_buf: update buffer which is used to collect update data or data for
 *           atomic LEB change
 *
 * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
 * @checked: %1 if this static volume was checked
 * @corrupted: %1 if the volume is corrupted (static volumes only)
 * @upd_marker: %1 if the update marker is set for this volume
 * @updating: %1 if the volume is being updated
 * @changing_leb: %1 if the atomic LEB change ioctl command is in progress
 * @direct_writes: %1 if direct writes are enabled for this volume
 *
 * The @corrupted field indicates that the volume's contents is corrupted.
 * Since UBI protects only static volumes, this field is not relevant to
 * dynamic volumes - it is user's responsibility to assure their data
 * integrity.
 *
 * The @upd_marker flag indicates that this volume is either being updated at
 * the moment or is damaged because of an unclean reboot.
 */
struct ubi_volume {
	struct device dev