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1 /*
2  * Copyright (c) International Business Machines Corp., 2006
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
12  * the GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17  *
18  * Author: Artem Bityutskiy (Битюцкий Артём)
19  */
20 
21 #ifndef __LINUX_UBI_H__
22 #define __LINUX_UBI_H__
23 
24 #include <linux/ioctl.h>
25 #include <linux/types.h>
26 #include <mtd/ubi-user.h>
27 
28 /* All voumes/LEBs */
29 #define UBI_ALL -1
30 
31 /*
32  * enum ubi_open_mode - UBI volume open mode constants.
33  *
34  * UBI_READONLY: read-only mode
35  * UBI_READWRITE: read-write mode
36  * UBI_EXCLUSIVE: exclusive mode
37  */
38 enum {
39 	UBI_READONLY = 1,
40 	UBI_READWRITE,
41 	UBI_EXCLUSIVE
42 };
43 
44 /**
45  * struct ubi_volume_info - UBI volume description data structure.
46  * @vol_id: volume ID
47  * @ubi_num: UBI device number this volume belongs to
48  * @size: how many physical eraseblocks are reserved for this volume
49  * @used_bytes: how many bytes of data this volume contains
50  * @used_ebs: how many physical eraseblocks of this volume actually contain any
51  *            data
52  * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
53  * @corrupted: non-zero if the volume is corrupted (static volumes only)
54  * @upd_marker: non-zero if the volume has update marker set
55  * @alignment: volume alignment
56  * @usable_leb_size: how many bytes are available in logical eraseblocks of
57  *                   this volume
58  * @name_len: volume name length
59  * @name: volume name
60  * @cdev: UBI volume character device major and minor numbers
61  *
62  * The @corrupted flag is only relevant to static volumes and is always zero
63  * for dynamic ones. This is because UBI does not care about dynamic volume
64  * data protection and only cares about protecting static volume data.
65  *
66  * The @upd_marker flag is set if the volume update operation was interrupted.
67  * Before touching the volume data during the update operation, UBI first sets
68  * the update marker flag for this volume. If the volume update operation was
69  * further interrupted, the update marker indicates this. If the update marker
70  * is set, the contents of the volume is certainly damaged and a new volume
71  * update operation has to be started.
72  *
73  * To put it differently, @corrupted and @upd_marker fields have different
74  * semantics:
75  *     o the @corrupted flag means that this static volume is corrupted for some
76  *       reasons, but not because an interrupted volume update
77  *     o the @upd_marker field means that the volume is damaged because of an
78  *       interrupted update operation.
79  *
80  * I.e., the @corrupted flag is never set if the @upd_marker flag is set.
81  *
82  * The @used_bytes and @used_ebs fields are only really needed for static
83  * volumes and contain the number of bytes stored in this static volume and how
84  * many eraseblock this data occupies. In case of dynamic volumes, the
85  * @used_bytes field is equivalent to @size*@usable_leb_size, and the @used_ebs
86  * field is equivalent to @size.
87  *
88  * In general, logical eraseblock size is a property of the UBI device, not
89  * of the UBI volume. Indeed, the logical eraseblock size depends on the
90  * physical eraseblock size and on how much bytes UBI headers consume. But
91  * because of the volume alignment (@alignment), the usable size of logical
92  * eraseblocks if a volume may be less. The following equation is true:
93  *	@usable_leb_size = LEB size - (LEB size mod @alignment),
94  * where LEB size is the logical eraseblock size defined by the UBI device.
95  *
96  * The alignment is multiple to the minimal flash input/output unit size or %1
97  * if all the available space is used.
98  *
99  * To put this differently, alignment may be considered is a way to change
100  * volume logical eraseblock sizes.
101  */
102 struct ubi_volume_info {
103 	int ubi_num;
104 	int vol_id;
105 	int size;
106 	long long used_bytes;
107 	int used_ebs;
108 	int vol_type;
109 	int corrupted;
110 	int upd_marker;
111 	int alignment;
112 	int usable_leb_size;
113 	int name_len;
114 	const char *name;
115 	dev_t cdev;
116 };
117 
118 /**
119  * struct ubi_device_info - UBI device description data structure.
120  * @ubi_num: ubi device number
121  * @leb_size: logical eraseblock size on this UBI device
122  * @leb_start: starting offset of logical eraseblocks within physical
123  *             eraseblocks
124  * @min_io_size: minimal I/O unit size
125  * @max_write_size: maximum amount of bytes the underlying flash can write at a
126  *                  time (MTD write buffer size)
127  * @ro_mode: if this device is in read-only mode
128  * @cdev: UBI character device major and minor numbers
129  *
130  * Note, @leb_size is the logical eraseblock size offered by the UBI device.
131  * Volumes of this UBI device may have smaller logical eraseblock size if their
132  * alignment is not equivalent to %1.
133  *
134  * The @max_write_size field describes flash write maximum write unit. For
135  * example, NOR flash allows for changing individual bytes, so @min_io_size is
136  * %1. However, it does not mean than NOR flash has to write data byte-by-byte.
137  * Instead, CFI NOR flashes have a write-buffer of, e.g., 64 bytes, and when
138  * writing large chunks of data, they write 64-bytes at a time. Obviously, this
139  * improves write throughput.
140  *
141  * Also, the MTD device may have N interleaved (striped) flash chips
142  * underneath, in which case @min_io_size can be physical min. I/O size of
143  * single flash chip, while @max_write_size can be N * @min_io_size.
144  *
145  * The @max_write_size field is always greater or equivalent to @min_io_size.
146  * E.g., some NOR flashes may have (@min_io_size = 1, @max_write_size = 64). In
147  * contrast, NAND flashes usually have @min_io_size = @max_write_size = NAND
148  * page size.
149  */
150 struct ubi_device_info {
151 	int ubi_num;
152 	int leb_size;
153 	int leb_start;
154 	int min_io_size;
155 	int max_write_size;
156 	int ro_mode;
157 	dev_t cdev;
158 };
159 
160 /*
161  * Volume notification types.
162  * @UBI_VOLUME_ADDED: a volume has been added (an UBI device was attached or a
163  *                    volume was created)
164  * @UBI_VOLUME_REMOVED: a volume has been removed (an UBI device was detached
165  *			or a volume was removed)
166  * @UBI_VOLUME_RESIZED: a volume has been re-sized
167  * @UBI_VOLUME_RENAMED: a volume has been re-named
168  * @UBI_VOLUME_UPDATED: data has been written to a volume
169  *
170  * These constants define which type of event has happened when a volume
171  * notification function is invoked.
172  */
173 enum {
174 	UBI_VOLUME_ADDED,
175 	UBI_VOLUME_REMOVED,
176 	UBI_VOLUME_RESIZED,
177 	UBI_VOLUME_RENAMED,
178 	UBI_VOLUME_UPDATED,
179 };
180 
181 /*
182  * struct ubi_notification - UBI notification description structure.
183  * @di: UBI device description object
184  * @vi: UBI volume description object
185  *
186  * UBI notifiers are called with a pointer to an object of this type. The
187  * object describes the notification. Namely, it provides a description of the
188  * UBI device and UBI volume the notification informs about.
189  */
190 struct ubi_notification {
191 	struct ubi_device_info di;
192 	struct ubi_volume_info vi;
193 };
194 
195 /* UBI descriptor given to users when they open UBI volumes */
196 struct ubi_volume_desc;
197 
198 int ubi_get_device_info(int ubi_num, struct ubi_device_info *di);
199 void ubi_get_volume_info(struct ubi_volume_desc *desc,
200 			 struct ubi_volume_info *vi);
201 struct ubi_volume_desc *ubi_open_volume(int ubi_num, int vol_id, int mode);
202 struct ubi_volume_desc *ubi_open_volume_nm(int ubi_num, const char *name,
203 					   int mode);
204 struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode);
205 
206 int ubi_register_volume_notifier(struct notifier_block *nb,
207 				 int ignore_existing);
208 int ubi_unregister_volume_notifier(struct notifier_block *nb);
209 
210 void ubi_close_volume(struct ubi_volume_desc *desc);
211 int ubi_leb_read(struct ubi_volume_desc *desc, int lnum, char *buf, int offset,
212 		 int len, int check);
213 int ubi_leb_write(struct ubi_volume_desc *desc, int lnum, const void *buf,
214 		  int offset, int len);
215 int ubi_leb_change(struct ubi_volume_desc *desc, int lnum, const void *buf,
216 		   int len);
217 int ubi_leb_erase(struct ubi_volume_desc *desc, int lnum);
218 int ubi_leb_unmap(struct ubi_volume_desc *desc, int lnum);
219 int ubi_leb_map(struct ubi_volume_desc *desc, int lnum);
220 int ubi_is_mapped(struct ubi_volume_desc *desc, int lnum);
221 int ubi_sync(int ubi_num);
222 int ubi_flush(int ubi_num, int vol_id, int lnum);
223 
224 /*
225  * This function is the same as the 'ubi_leb_read()' function, but it does not
226  * provide the checking capability.
227  */
ubi_read(struct ubi_volume_desc * desc,int lnum,char * buf,int offset,int len)228 static inline int ubi_read(struct ubi_volume_desc *desc, int lnum, char *buf,
229 			   int offset, int len)
230 {
231 	return ubi_leb_read(desc, lnum, buf, offset, len, 0);
232 }
233 #endif /* !__LINUX_UBI_H__ */
234