2 * Copyright (c) International Business Machines Corp., 2006
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.
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.
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
18 * Authors: Artem Bityutskiy (Битюцкий Артём)
26 * This file defines the layout of UBI headers and all the other UBI on-flash
30 #ifndef __UBI_MEDIA_H__
31 #define __UBI_MEDIA_H__
33 #include <asm/byteorder.h>
35 /* The version of UBI images supported by this implementation */
38 /* The highest erase counter value supported by this implementation */
39 #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF
41 /* The initial CRC32 value used when calculating CRC checksums */
42 #define UBI_CRC32_INIT 0xFFFFFFFFU
44 /* Erase counter header magic number (ASCII "UBI#") */
45 #define UBI_EC_HDR_MAGIC 0x55424923
46 /* Volume identifier header magic number (ASCII "UBI!") */
47 #define UBI_VID_HDR_MAGIC 0x55424921
50 * Volume type constants used in the volume identifier header.
52 * @UBI_VID_DYNAMIC: dynamic volume
53 * @UBI_VID_STATIC: static volume
61 * Volume flags used in the volume table record.
63 * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume
65 * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume
66 * table. UBI automatically re-sizes the volume which has this flag and makes
67 * the volume to be of largest possible size. This means that if after the
68 * initialization UBI finds out that there are available physical eraseblocks
69 * present on the device, it automatically appends all of them to the volume
70 * (the physical eraseblocks reserved for bad eraseblocks handling and other
71 * reserved physical eraseblocks are not taken). So, if there is a volume with
72 * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical
73 * eraseblocks will be zero after UBI is loaded, because all of them will be
74 * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared
75 * after the volume had been initialized.
77 * The auto-resize feature is useful for device production purposes. For
78 * example, different NAND flash chips may have different amount of initial bad
79 * eraseblocks, depending of particular chip instance. Manufacturers of NAND
80 * chips usually guarantee that the amount of initial bad eraseblocks does not
81 * exceed certain percent, e.g. 2%. When one creates an UBI image which will be
82 * flashed to the end devices in production, he does not know the exact amount
83 * of good physical eraseblocks the NAND chip on the device will have, but this
84 * number is required to calculate the volume sized and put them to the volume
85 * table of the UBI image. In this case, one of the volumes (e.g., the one
86 * which will store the root file system) is marked as "auto-resizable", and
87 * UBI will adjust its size on the first boot if needed.
89 * Note, first UBI reserves some amount of physical eraseblocks for bad
90 * eraseblock handling, and then re-sizes the volume, not vice-versa. This
91 * means that the pool of reserved physical eraseblocks will always be present.
94 UBI_VTBL_AUTORESIZE_FLG
= 0x01,
98 * Compatibility constants used by internal volumes.
100 * @UBI_COMPAT_DELETE: delete this internal volume before anything is written
102 * @UBI_COMPAT_RO: attach this device in read-only mode
103 * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its
104 * physical eraseblocks, don't allow the wear-leveling
105 * sub-system to move them
106 * @UBI_COMPAT_REJECT: reject this UBI image
109 UBI_COMPAT_DELETE
= 1,
111 UBI_COMPAT_PRESERVE
= 4,
112 UBI_COMPAT_REJECT
= 5
115 /* Sizes of UBI headers */
116 #define UBI_EC_HDR_SIZE sizeof(struct ubi_ec_hdr)
117 #define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr)
119 /* Sizes of UBI headers without the ending CRC */
120 #define UBI_EC_HDR_SIZE_CRC (UBI_EC_HDR_SIZE - sizeof(__be32))
121 #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32))
124 * struct ubi_ec_hdr - UBI erase counter header.
125 * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC)
126 * @version: version of UBI implementation which is supposed to accept this
128 * @padding1: reserved for future, zeroes
129 * @ec: the erase counter
130 * @vid_hdr_offset: where the VID header starts
131 * @data_offset: where the user data start
132 * @image_seq: image sequence number
133 * @padding2: reserved for future, zeroes
134 * @hdr_crc: erase counter header CRC checksum
136 * The erase counter header takes 64 bytes and has a plenty of unused space for
137 * future usage. The unused fields are zeroed. The @version field is used to
138 * indicate the version of UBI implementation which is supposed to be able to
139 * work with this UBI image. If @version is greater than the current UBI
140 * version, the image is rejected. This may be useful in future if something
141 * is changed radically. This field is duplicated in the volume identifier
144 * The @vid_hdr_offset and @data_offset fields contain the offset of the the
145 * volume identifier header and user data, relative to the beginning of the
146 * physical eraseblock. These values have to be the same for all physical
149 * The @image_seq field is used to validate a UBI image that has been prepared
150 * for a UBI device. The @image_seq value can be any value, but it must be the
151 * same on all eraseblocks. UBI will ensure that all new erase counter headers
152 * also contain this value, and will check the value when attaching the flash.
153 * One way to make use of @image_seq is to increase its value by one every time
154 * an image is flashed over an existing image, then, if the flashing does not
155 * complete, UBI will detect the error when attaching the media.
161 __be64 ec
; /* Warning: the current limit is 31-bit anyway! */
162 __be32 vid_hdr_offset
;
170 * struct ubi_vid_hdr - on-flash UBI volume identifier header.
171 * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC)
172 * @version: UBI implementation version which is supposed to accept this UBI
173 * image (%UBI_VERSION)
174 * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC)
175 * @copy_flag: if this logical eraseblock was copied from another physical
176 * eraseblock (for wear-leveling reasons)
177 * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE,
178 * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT)
179 * @vol_id: ID of this volume
180 * @lnum: logical eraseblock number
181 * @padding1: reserved for future, zeroes
182 * @data_size: how many bytes of data this logical eraseblock contains
183 * @used_ebs: total number of used logical eraseblocks in this volume
184 * @data_pad: how many bytes at the end of this physical eraseblock are not
186 * @data_crc: CRC checksum of the data stored in this logical eraseblock
187 * @padding2: reserved for future, zeroes
188 * @sqnum: sequence number
189 * @padding3: reserved for future, zeroes
190 * @hdr_crc: volume identifier header CRC checksum
192 * The @sqnum is the value of the global sequence counter at the time when this
193 * VID header was created. The global sequence counter is incremented each time
194 * UBI writes a new VID header to the flash, i.e. when it maps a logical
195 * eraseblock to a new physical eraseblock. The global sequence counter is an
196 * unsigned 64-bit integer and we assume it never overflows. The @sqnum
197 * (sequence number) is used to distinguish between older and newer versions of
198 * logical eraseblocks.
200 * There are 2 situations when there may be more than one physical eraseblock
201 * corresponding to the same logical eraseblock, i.e., having the same @vol_id
202 * and @lnum values in the volume identifier header. Suppose we have a logical
203 * eraseblock L and it is mapped to the physical eraseblock P.
205 * 1. Because UBI may erase physical eraseblocks asynchronously, the following
206 * situation is possible: L is asynchronously erased, so P is scheduled for
207 * erasure, then L is written to,i.e. mapped to another physical eraseblock P1,
208 * so P1 is written to, then an unclean reboot happens. Result - there are 2
209 * physical eraseblocks P and P1 corresponding to the same logical eraseblock
210 * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the
213 * 2. From time to time UBI moves logical eraseblocks to other physical
214 * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P
215 * to P1, and an unclean reboot happens before P is physically erased, there
216 * are two physical eraseblocks P and P1 corresponding to L and UBI has to
217 * select one of them when the flash is attached. The @sqnum field says which
218 * PEB is the original (obviously P will have lower @sqnum) and the copy. But
219 * it is not enough to select the physical eraseblock with the higher sequence
220 * number, because the unclean reboot could have happen in the middle of the
221 * copying process, so the data in P is corrupted. It is also not enough to
222 * just select the physical eraseblock with lower sequence number, because the
223 * data there may be old (consider a case if more data was added to P1 after
224 * the copying). Moreover, the unclean reboot may happen when the erasure of P
225 * was just started, so it result in unstable P, which is "mostly" OK, but
226 * still has unstable bits.
228 * UBI uses the @copy_flag field to indicate that this logical eraseblock is a
229 * copy. UBI also calculates data CRC when the data is moved and stores it at
230 * the @data_crc field of the copy (P1). So when UBI needs to pick one physical
231 * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is
232 * examined. If it is cleared, the situation* is simple and the newer one is
233 * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC
234 * checksum is correct, this physical eraseblock is selected (P1). Otherwise
235 * the older one (P) is selected.
237 * There are 2 sorts of volumes in UBI: user volumes and internal volumes.
238 * Internal volumes are not seen from outside and are used for various internal
239 * UBI purposes. In this implementation there is only one internal volume - the
240 * layout volume. Internal volumes are the main mechanism of UBI extensions.
241 * For example, in future one may introduce a journal internal volume. Internal
242 * volumes have their own reserved range of IDs.
244 * The @compat field is only used for internal volumes and contains the "degree
245 * of their compatibility". It is always zero for user volumes. This field
246 * provides a mechanism to introduce UBI extensions and to be still compatible
247 * with older UBI binaries. For example, if someone introduced a journal in
248 * future, he would probably use %UBI_COMPAT_DELETE compatibility for the
249 * journal volume. And in this case, older UBI binaries, which know nothing
250 * about the journal volume, would just delete this volume and work perfectly
251 * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image
252 * - it just ignores the Ext3fs journal.
254 * The @data_crc field contains the CRC checksum of the contents of the logical
255 * eraseblock if this is a static volume. In case of dynamic volumes, it does
256 * not contain the CRC checksum as a rule. The only exception is when the
257 * data of the physical eraseblock was moved by the wear-leveling sub-system,
258 * then the wear-leveling sub-system calculates the data CRC and stores it in
259 * the @data_crc field. And of course, the @copy_flag is %in this case.
261 * The @data_size field is used only for static volumes because UBI has to know
262 * how many bytes of data are stored in this eraseblock. For dynamic volumes,
263 * this field usually contains zero. The only exception is when the data of the
264 * physical eraseblock was moved to another physical eraseblock for
265 * wear-leveling reasons. In this case, UBI calculates CRC checksum of the
266 * contents and uses both @data_crc and @data_size fields. In this case, the
267 * @data_size field contains data size.
269 * The @used_ebs field is used only for static volumes and indicates how many
270 * eraseblocks the data of the volume takes. For dynamic volumes this field is
271 * not used and always contains zero.
273 * The @data_pad is calculated when volumes are created using the alignment
274 * parameter. So, effectively, the @data_pad field reduces the size of logical
275 * eraseblocks of this volume. This is very handy when one uses block-oriented
276 * software (say, cramfs) on top of the UBI volume.
297 /* Internal UBI volumes count */
298 #define UBI_INT_VOL_COUNT 1
301 * Starting ID of internal volumes: 0x7fffefff.
302 * There is reserved room for 4096 internal volumes.
304 #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096)
306 /* The layout volume contains the volume table */
308 #define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START
309 #define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC
310 #define UBI_LAYOUT_VOLUME_ALIGN 1
311 #define UBI_LAYOUT_VOLUME_EBS 2
312 #define UBI_LAYOUT_VOLUME_NAME "layout volume"
313 #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT
315 /* The maximum number of volumes per one UBI device */
316 #define UBI_MAX_VOLUMES 128
318 /* The maximum volume name length */
319 #define UBI_VOL_NAME_MAX 127
321 /* Size of the volume table record */
322 #define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record)
324 /* Size of the volume table record without the ending CRC */
325 #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32))
328 * struct ubi_vtbl_record - a record in the volume table.
329 * @reserved_pebs: how many physical eraseblocks are reserved for this volume
330 * @alignment: volume alignment
331 * @data_pad: how many bytes are unused at the end of the each physical
332 * eraseblock to satisfy the requested alignment
333 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
334 * @upd_marker: if volume update was started but not finished
335 * @name_len: volume name length
336 * @name: the volume name
337 * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG)
338 * @padding: reserved, zeroes
339 * @crc: a CRC32 checksum of the record
341 * The volume table records are stored in the volume table, which is stored in
342 * the layout volume. The layout volume consists of 2 logical eraseblock, each
343 * of which contains a copy of the volume table (i.e., the volume table is
344 * duplicated). The volume table is an array of &struct ubi_vtbl_record
345 * objects indexed by the volume ID.
347 * If the size of the logical eraseblock is large enough to fit
348 * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES
349 * records. Otherwise, it contains as many records as it can fit (i.e., size of
350 * logical eraseblock divided by sizeof(struct ubi_vtbl_record)).
352 * The @upd_marker flag is used to implement volume update. It is set to %1
353 * before update and set to %0 after the update. So if the update operation was
354 * interrupted, UBI knows that the volume is corrupted.
356 * The @alignment field is specified when the volume is created and cannot be
357 * later changed. It may be useful, for example, when a block-oriented file
358 * system works on top of UBI. The @data_pad field is calculated using the
359 * logical eraseblock size and @alignment. The alignment must be multiple to the
360 * minimal flash I/O unit. If @alignment is 1, all the available space of
361 * the physical eraseblocks is used.
363 * Empty records contain all zeroes and the CRC checksum of those zeroes.
365 struct ubi_vtbl_record
{
366 __be32 reserved_pebs
;
372 __u8 name
[UBI_VOL_NAME_MAX
+1];
378 /* UBI fastmap on-flash data structures */
380 #define UBI_FM_SB_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 1)
381 #define UBI_FM_DATA_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 2)
383 /* fastmap on-flash data structure format version */
384 #define UBI_FM_FMT_VERSION 1
386 #define UBI_FM_SB_MAGIC 0x7B11D69F
387 #define UBI_FM_HDR_MAGIC 0xD4B82EF7
388 #define UBI_FM_VHDR_MAGIC 0xFA370ED1
389 #define UBI_FM_POOL_MAGIC 0x67AF4D08
390 #define UBI_FM_EBA_MAGIC 0xf0c040a8
392 /* A fastmap supber block can be located between PEB 0 and
393 * UBI_FM_MAX_START */
394 #define UBI_FM_MAX_START 64
396 /* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */
397 #define UBI_FM_MAX_BLOCKS 32
399 /* 5% of the total number of PEBs have to be scanned while attaching
401 * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and
402 * UBI_FM_MAX_POOL_SIZE */
403 #define UBI_FM_MIN_POOL_SIZE 8
404 #define UBI_FM_MAX_POOL_SIZE 256
407 * struct ubi_fm_sb - UBI fastmap super block
408 * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC)
409 * @version: format version of this fastmap
410 * @data_crc: CRC over the fastmap data
411 * @used_blocks: number of PEBs used by this fastmap
412 * @block_loc: an array containing the location of all PEBs of the fastmap
413 * @block_ec: the erase counter of each used PEB
414 * @sqnum: highest sequence number value at the time while taking the fastmap
423 __be32 block_loc
[UBI_FM_MAX_BLOCKS
];
424 __be32 block_ec
[UBI_FM_MAX_BLOCKS
];
430 * struct ubi_fm_hdr - header of the fastmap data set
431 * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC)
432 * @free_peb_count: number of free PEBs known by this fastmap
433 * @used_peb_count: number of used PEBs known by this fastmap
434 * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap
435 * @bad_peb_count: number of bad PEBs known by this fastmap
436 * @erase_peb_count: number of bad PEBs which have to be erased
437 * @vol_count: number of UBI volumes known by this fastmap
441 __be32 free_peb_count
;
442 __be32 used_peb_count
;
443 __be32 scrub_peb_count
;
444 __be32 bad_peb_count
;
445 __be32 erase_peb_count
;
450 /* struct ubi_fm_hdr is followed by two struct ubi_fm_scan_pool */
453 * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching
454 * @magic: pool magic numer (%UBI_FM_POOL_MAGIC)
455 * @size: current pool size
456 * @max_size: maximal pool size
457 * @pebs: an array containing the location of all PEBs in this pool
459 struct ubi_fm_scan_pool
{
463 __be32 pebs
[UBI_FM_MAX_POOL_SIZE
];
467 /* ubi_fm_scan_pool is followed by nfree+nused struct ubi_fm_ec records */
470 * struct ubi_fm_ec - stores the erase counter of a PEB
472 * @ec: ec of this PEB
480 * struct ubi_fm_volhdr - Fastmap volume header
481 * it identifies the start of an eba table
482 * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC)
483 * @vol_id: volume id of the fastmapped volume
484 * @vol_type: type of the fastmapped volume
485 * @data_pad: data_pad value of the fastmapped volume
486 * @used_ebs: number of used LEBs within this volume
487 * @last_eb_bytes: number of bytes used in the last LEB
489 struct ubi_fm_volhdr
{
496 __be32 last_eb_bytes
;
500 /* struct ubi_fm_volhdr is followed by one struct ubi_fm_eba records */
503 * struct ubi_fm_eba - denotes an association between a PEB and LEB
504 * @magic: EBA table magic number
505 * @reserved_pebs: number of table entries
506 * @pnum: PEB number of LEB (LEB is the index)
510 __be32 reserved_pebs
;
513 #endif /* !__UBI_MEDIA_H__ */