summaryrefslogtreecommitdiffstats
path: root/include/mtd/ubi-user.h
blob: 2dc2eb2b8e2210ea17f29602473b4d9bc7c4ac66 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
/*
 * Copyright (c) International Business Machines Corp., 2006
 *
 * 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_USER_H__
#define __UBI_USER_H__

/*
 * UBI device creation (the same as MTD device attachment)
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * MTD devices may be attached using %UBI_IOCATT ioctl command of the UBI
 * control device. The caller has to properly fill and pass
 * &struct ubi_attach_req object - UBI will attach the MTD device specified in
 * the request and return the newly created UBI device number as the ioctl
 * return value.
 *
 * UBI device deletion (the same as MTD device detachment)
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * An UBI device maybe deleted with %UBI_IOCDET ioctl command of the UBI
 * control device.
 *
 * UBI volume creation
 * ~~~~~~~~~~~~~~~~~~~
 *
 * UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character
 * device. A &struct ubi_mkvol_req object has to be properly filled and a
 * pointer to it has to be passed to the IOCTL.
 *
 * UBI volume deletion
 * ~~~~~~~~~~~~~~~~~~~
 *
 * To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character
 * device should be used. A pointer to the 32-bit volume ID hast to be passed
 * to the IOCTL.
 *
 * UBI volume re-size
 * ~~~~~~~~~~~~~~~~~~
 *
 * To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character
 * device should be used. A &struct ubi_rsvol_req object has to be properly
 * filled and a pointer to it has to be passed to the IOCTL.
 *
 * UBI volumes re-name
 * ~~~~~~~~~~~~~~~~~~~
 *
 * To re-name several volumes atomically at one go, the %UBI_IOCRNVOL command
 * of the UBI character device should be used. A &struct ubi_rnvol_req object
 * has to be properly filled and a pointer to it has to be passed to the IOCTL.
 *
 * UBI volume update
 * ~~~~~~~~~~~~~~~~~
 *
 * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the
 * corresponding UBI volume character device. A pointer to a 64-bit update
 * size should be passed to the IOCTL. After this, UBI expects user to write
 * this number of bytes to the volume character device. The update is finished
 * when the claimed number of bytes is passed. So, the volume update sequence
 * is something like:
 *
 * fd = open("/dev/my_volume");
 * ioctl(fd, UBI_IOCVOLUP, &image_size);
 * write(fd, buf, image_size);
 * close(fd);
 *
 * Atomic eraseblock change
 * ~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * Atomic eraseblock change operation is done via the %UBI_IOCEBCH IOCTL
 * command of the corresponding UBI volume character device. A pointer to
 * &struct ubi_leb_change_req has to be passed to the IOCTL. Then the user is
 * expected to write the requested amount of bytes. This is similar to the
 * "volume update" IOCTL.
 */

/*
 * When a new UBI volume or UBI device is created, users may either specify the
 * volume/device number they want to create or to let UBI automatically assign
 * the number using these constants.
 */
#define UBI_VOL_NUM_AUTO (-1)
#define UBI_DEV_NUM_AUTO (-1)

/* Maximum volume name length */
#define UBI_MAX_VOLUME_NAME 127

/* IOCTL commands of UBI character devices */

#define UBI_IOC_MAGIC 'o'

/* Create an UBI volume */
#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req)
/* Remove an UBI volume */
#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t)
/* Re-size an UBI volume */
#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req)
/* Re-name volumes */
#define UBI_IOCRNVOL _IOW(UBI_IOC_MAGIC, 3, struct ubi_rnvol_req)

/* IOCTL commands of the UBI control character device */

#define UBI_CTRL_IOC_MAGIC 'o'

/* Attach an MTD device */
#define UBI_IOCATT _IOW(UBI_CTRL_IOC_MAGIC, 64, struct ubi_attach_req)
/* Detach an MTD device */
#define UBI_IOCDET _IOW(UBI_CTRL_IOC_MAGIC, 65, int32_t)

/* IOCTL commands of UBI volume character devices */

#define UBI_VOL_IOC_MAGIC 'O'

/* Start UBI volume update */
#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t)
/* An eraseblock erasure command, used for debugging, disabled by default */
#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t)
/* An atomic eraseblock change command */
#define UBI_IOCEBCH _IOW(UBI_VOL_IOC_MAGIC, 2, int32_t)

/* Maximum MTD device name length supported by UBI */
#define MAX_UBI_MTD_NAME_LEN 127

/* Maximum amount of UBI volumes that can be re-named at one go */
#define UBI_MAX_RNVOL 32

/*
 * UBI data type hint constants.
 *
 * UBI_LONGTERM: long-term data
 * UBI_SHORTTERM: short-term data
 * UBI_UNKNOWN: data persistence is unknown
 *
 * These constants are used when data is written to UBI volumes in order to
 * help the UBI wear-leveling unit to find more appropriate physical
 * eraseblocks.
 */
enum {
	UBI_LONGTERM  = 1,
	UBI_SHORTTERM = 2,
	UBI_UNKNOWN   = 3,
};

/*
 * UBI volume type constants.
 *
 * @UBI_DYNAMIC_VOLUME: dynamic volume
 * @UBI_STATIC_VOLUME:  static volume
 */
enum {
	UBI_DYNAMIC_VOLUME = 3,
	UBI_STATIC_VOLUME  = 4,
};

/**
 * struct ubi_attach_req - attach MTD device request.
 * @ubi_num: UBI device number to create
 * @mtd_num: MTD device number to attach
 * @vid_hdr_offset: VID header offset (use defaults if %0)
 * @padding: reserved for future, not used, has to be zeroed
 *
 * This data structure is used to specify MTD device UBI has to attach and the
 * parameters it has to use. The number which should be assigned to the new UBI
 * device is passed in @ubi_num. UBI may automatically assign the number if
 * @UBI_DEV_NUM_AUTO is passed. In this case, the device number is returned in
 * @ubi_num.
 *
 * Most applications should pass %0 in @vid_hdr_offset to make UBI use default
 * offset of the VID header within physical eraseblocks. The default offset is
 * the next min. I/O unit after the EC header. For example, it will be offset
 * 512 in case of a 512 bytes page NAND flash with no sub-page support. Or
 * it will be 512 in case of a 2KiB page NAND flash with 4 512-byte sub-pages.
 *
 * But in rare cases, if this optimizes things, the VID header may be placed to
 * a different offset. For example, the boot-loader might do things faster if
 * the VID header sits at the end of the first 2KiB NAND page with 4 sub-pages.
 * As the boot-loader would not normally need to read EC headers (unless it
 * needs UBI in RW mode), it might be faster to calculate ECC. This is weird
 * example, but it real-life example. So, in this example, @vid_hdr_offer would
 * be 2KiB-64 bytes = 1984. Note, that this position is not even 512-bytes
 * aligned, which is OK, as UBI is clever enough to realize this is 4th
 * sub-page of the first page and add needed padding.
 */
struct ubi_attach_req {
	int32_t ubi_num;
	int32_t mtd_num;
	int32_t vid_hdr_offset;
	int8_t padding[12];
};

/**
 * struct ubi_mkvol_req - volume description data structure used in
 *                        volume creation requests.
 * @vol_id: volume number
 * @alignment: volume alignment
 * @bytes: volume size in bytes
 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
 * @padding1: reserved for future, not used, has to be zeroed
 * @name_len: volume name length
 * @padding2: reserved for future, not used, has to be zeroed
 * @name: volume name
 *
 * This structure is used by user-space programs when creating new volumes. The
 * @used_bytes field is only necessary when creating static volumes.
 *
 * The @alignment field specifies the required alignment of the volume logical
 * eraseblock. This means, that the size of logical eraseblocks will be aligned
 * to this number, i.e.,
 *	(UBI device logical eraseblock size) mod (@alignment) = 0.
 *
 * To put it differently, the logical eraseblock of this volume may be slightly
 * shortened in order to make it properly aligned. The alignment has to be
 * multiple of the flash minimal input/output unit, or %1 to utilize the entire
 * available space of logical eraseblocks.
 *
 * The @alignment field may be useful, for example, when one wants to maintain
 * a block device on top of an UBI volume. In this case, it is desirable to fit
 * an integer number of blocks in logical eraseblocks of this UBI volume. With
 * alignment it is possible to update this volume using plane UBI volume image
 * BLOBs, without caring about how to properly align them.
 */
struct ubi_mkvol_req {
	int32_t vol_id;
	int32_t alignment;
	int64_t bytes;
	int8_t vol_type;
	int8_t padding1;
	int16_t name_len;
	int8_t padding2[4];
	char name[UBI_MAX_VOLUME_NAME + 1];
} __attribute__ ((packed));

/**
 * struct ubi_rsvol_req - a data structure used in volume re-size requests.
 * @vol_id: ID of the volume to re-size
 * @bytes: new size of the volume in bytes
 *
 * Re-sizing is possible for both dynamic and static volumes. But while dynamic
 * volumes may be re-sized arbitrarily, static volumes cannot be made to be
 * smaller than the number of bytes they bear. To arbitrarily shrink a static
 * volume, it must be wiped out first (by means of volume update operation with
 * zero number of bytes).
 */
struct ubi_rsvol_req {
	int64_t bytes;
	int32_t vol_id;
} __attribute__ ((packed));

/**
 * struct ubi_rnvol_req - volumes re-name request.
 * @count: count of volumes to re-name
 * @padding1:  reserved for future, not used, has to be zeroed
 * @vol_id: ID of the volume to re-name
 * @name_len: name length
 * @padding2:  reserved for future, not used, has to be zeroed
 * @name: new volume name
 *
 * UBI allows to re-name up to %32 volumes at one go. The count of volumes to
 * re-name is specified in the @count field. The ID of the volumes to re-name
 * and the new names are specified in the @vol_id and @name fields.
 *
 * The UBI volume re-name operation is atomic, which means that should power cut
 * happen, the volumes will have either old name or new name. So the possible
 * use-cases of this command is atomic upgrade. Indeed, to upgrade, say, volumes
 * A and B one may create temporary volumes %A1 and %B1 with the new contents,
 * then atomically re-name A1->A and B1->B, in which case old %A and %B will
 * be removed.
 *
 * If it is not desirable to remove old A and B, the re-name request has to
 * contain 4 entries: A1->A, A->A1, B1->B, B->B1, in which case old A1 and B1
 * become A and B, and old A and B will become A1 and B1.
 *
 * It is also OK to request: A1->A, A1->X, B1->B, B->Y, in which case old A1
 * and B1 become A and B, and old A and B become X and Y.
 *
 * In other words, in case of re-naming into an existing volume name, the
 * existing volume is removed, unless it is re-named as well at the same
 * re-name request.
 */
struct ubi_rnvol_req {
	int32_t count;
	int8_t padding1[12];
	struct {
		int32_t vol_id;
		int16_t name_len;
		int8_t  padding2[2];
		char    name[UBI_MAX_VOLUME_NAME + 1];
	} ents[UBI_MAX_RNVOL];
} __attribute__ ((packed));

/**
 * struct ubi_leb_change_req - a data structure used in atomic logical
 *                             eraseblock change requests.
 * @lnum: logical eraseblock number to change
 * @bytes: how many bytes will be written to the logical eraseblock
 * @dtype: data type (%UBI_LONGTERM, %UBI_SHORTTERM, %UBI_UNKNOWN)
 * @padding: reserved for future, not used, has to be zeroed
 */
struct ubi_leb_change_req {
	int32_t lnum;
	int32_t bytes;
	int8_t  dtype;
	int8_t  padding[7];
} __attribute__ ((packed));

#endif /* __UBI_USER_H__ */