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1/* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */2/*3 * Copyright (C) International Business Machines Corp., 20064 * Authors: Artem Bityutskiy (Битюцкий Артём)5 * Thomas Gleixner6 * Frank Haverkamp7 * Oliver Lohmann8 * Andreas Arnez9 *10 * This file defines the layout of UBI headers and all the other UBI on-flash11 * data structures.12 */13 14#ifndef __UBI_MEDIA_H__15#define __UBI_MEDIA_H__16 17#include <asm/byteorder.h>18 19/* The version of UBI images supported by this implementation */20#define UBI_VERSION 121 22/* The highest erase counter value supported by this implementation */23#define UBI_MAX_ERASECOUNTER 0x7FFFFFFF24 25/* The initial CRC32 value used when calculating CRC checksums */26#define UBI_CRC32_INIT 0xFFFFFFFFU27 28/* Erase counter header magic number (ASCII "UBI#") */29#define UBI_EC_HDR_MAGIC 0x5542492330/* Volume identifier header magic number (ASCII "UBI!") */31#define UBI_VID_HDR_MAGIC 0x5542492132 33/*34 * Volume type constants used in the volume identifier header.35 *36 * @UBI_VID_DYNAMIC: dynamic volume37 * @UBI_VID_STATIC: static volume38 */39enum {40 UBI_VID_DYNAMIC = 1,41 UBI_VID_STATIC = 242};43 44/*45 * Volume flags used in the volume table record.46 *47 * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume48 * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at49 * open time. Should only be set on volumes that50 * are used by upper layers doing this kind of51 * check. Main use-case for this flag is52 * boot-time reduction53 *54 * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume55 * table. UBI automatically re-sizes the volume which has this flag and makes56 * the volume to be of largest possible size. This means that if after the57 * initialization UBI finds out that there are available physical eraseblocks58 * present on the device, it automatically appends all of them to the volume59 * (the physical eraseblocks reserved for bad eraseblocks handling and other60 * reserved physical eraseblocks are not taken). So, if there is a volume with61 * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical62 * eraseblocks will be zero after UBI is loaded, because all of them will be63 * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared64 * after the volume had been initialized.65 *66 * The auto-resize feature is useful for device production purposes. For67 * example, different NAND flash chips may have different amount of initial bad68 * eraseblocks, depending of particular chip instance. Manufacturers of NAND69 * chips usually guarantee that the amount of initial bad eraseblocks does not70 * exceed certain percent, e.g. 2%. When one creates an UBI image which will be71 * flashed to the end devices in production, he does not know the exact amount72 * of good physical eraseblocks the NAND chip on the device will have, but this73 * number is required to calculate the volume sized and put them to the volume74 * table of the UBI image. In this case, one of the volumes (e.g., the one75 * which will store the root file system) is marked as "auto-resizable", and76 * UBI will adjust its size on the first boot if needed.77 *78 * Note, first UBI reserves some amount of physical eraseblocks for bad79 * eraseblock handling, and then re-sizes the volume, not vice-versa. This80 * means that the pool of reserved physical eraseblocks will always be present.81 */82enum {83 UBI_VTBL_AUTORESIZE_FLG = 0x01,84 UBI_VTBL_SKIP_CRC_CHECK_FLG = 0x02,85};86 87/*88 * Compatibility constants used by internal volumes.89 *90 * @UBI_COMPAT_DELETE: delete this internal volume before anything is written91 * to the flash92 * @UBI_COMPAT_RO: attach this device in read-only mode93 * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its94 * physical eraseblocks, don't allow the wear-leveling95 * sub-system to move them96 * @UBI_COMPAT_REJECT: reject this UBI image97 */98enum {99 UBI_COMPAT_DELETE = 1,100 UBI_COMPAT_RO = 2,101 UBI_COMPAT_PRESERVE = 4,102 UBI_COMPAT_REJECT = 5103};104 105/* Sizes of UBI headers */106#define UBI_EC_HDR_SIZE sizeof(struct ubi_ec_hdr)107#define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr)108 109/* Sizes of UBI headers without the ending CRC */110#define UBI_EC_HDR_SIZE_CRC (UBI_EC_HDR_SIZE - sizeof(__be32))111#define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32))112 113/**114 * struct ubi_ec_hdr - UBI erase counter header.115 * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC)116 * @version: version of UBI implementation which is supposed to accept this117 * UBI image118 * @padding1: reserved for future, zeroes119 * @ec: the erase counter120 * @vid_hdr_offset: where the VID header starts121 * @data_offset: where the user data start122 * @image_seq: image sequence number123 * @padding2: reserved for future, zeroes124 * @hdr_crc: erase counter header CRC checksum125 *126 * The erase counter header takes 64 bytes and has a plenty of unused space for127 * future usage. The unused fields are zeroed. The @version field is used to128 * indicate the version of UBI implementation which is supposed to be able to129 * work with this UBI image. If @version is greater than the current UBI130 * version, the image is rejected. This may be useful in future if something131 * is changed radically. This field is duplicated in the volume identifier132 * header.133 *134 * The @vid_hdr_offset and @data_offset fields contain the offset of the135 * volume identifier header and user data, relative to the beginning of the136 * physical eraseblock. These values have to be the same for all physical137 * eraseblocks.138 *139 * The @image_seq field is used to validate a UBI image that has been prepared140 * for a UBI device. The @image_seq value can be any value, but it must be the141 * same on all eraseblocks. UBI will ensure that all new erase counter headers142 * also contain this value, and will check the value when attaching the flash.143 * One way to make use of @image_seq is to increase its value by one every time144 * an image is flashed over an existing image, then, if the flashing does not145 * complete, UBI will detect the error when attaching the media.146 */147struct ubi_ec_hdr {148 __be32 magic;149 __u8 version;150 __u8 padding1[3];151 __be64 ec; /* Warning: the current limit is 31-bit anyway! */152 __be32 vid_hdr_offset;153 __be32 data_offset;154 __be32 image_seq;155 __u8 padding2[32];156 __be32 hdr_crc;157} __packed;158 159/**160 * struct ubi_vid_hdr - on-flash UBI volume identifier header.161 * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC)162 * @version: UBI implementation version which is supposed to accept this UBI163 * image (%UBI_VERSION)164 * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC)165 * @copy_flag: if this logical eraseblock was copied from another physical166 * eraseblock (for wear-leveling reasons)167 * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE,168 * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT)169 * @vol_id: ID of this volume170 * @lnum: logical eraseblock number171 * @padding1: reserved for future, zeroes172 * @data_size: how many bytes of data this logical eraseblock contains173 * @used_ebs: total number of used logical eraseblocks in this volume174 * @data_pad: how many bytes at the end of this physical eraseblock are not175 * used176 * @data_crc: CRC checksum of the data stored in this logical eraseblock177 * @padding2: reserved for future, zeroes178 * @sqnum: sequence number179 * @padding3: reserved for future, zeroes180 * @hdr_crc: volume identifier header CRC checksum181 *182 * The @sqnum is the value of the global sequence counter at the time when this183 * VID header was created. The global sequence counter is incremented each time184 * UBI writes a new VID header to the flash, i.e. when it maps a logical185 * eraseblock to a new physical eraseblock. The global sequence counter is an186 * unsigned 64-bit integer and we assume it never overflows. The @sqnum187 * (sequence number) is used to distinguish between older and newer versions of188 * logical eraseblocks.189 *190 * There are 2 situations when there may be more than one physical eraseblock191 * corresponding to the same logical eraseblock, i.e., having the same @vol_id192 * and @lnum values in the volume identifier header. Suppose we have a logical193 * eraseblock L and it is mapped to the physical eraseblock P.194 *195 * 1. Because UBI may erase physical eraseblocks asynchronously, the following196 * situation is possible: L is asynchronously erased, so P is scheduled for197 * erasure, then L is written to,i.e. mapped to another physical eraseblock P1,198 * so P1 is written to, then an unclean reboot happens. Result - there are 2199 * physical eraseblocks P and P1 corresponding to the same logical eraseblock200 * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the201 * flash.202 *203 * 2. From time to time UBI moves logical eraseblocks to other physical204 * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P205 * to P1, and an unclean reboot happens before P is physically erased, there206 * are two physical eraseblocks P and P1 corresponding to L and UBI has to207 * select one of them when the flash is attached. The @sqnum field says which208 * PEB is the original (obviously P will have lower @sqnum) and the copy. But209 * it is not enough to select the physical eraseblock with the higher sequence210 * number, because the unclean reboot could have happen in the middle of the211 * copying process, so the data in P is corrupted. It is also not enough to212 * just select the physical eraseblock with lower sequence number, because the213 * data there may be old (consider a case if more data was added to P1 after214 * the copying). Moreover, the unclean reboot may happen when the erasure of P215 * was just started, so it result in unstable P, which is "mostly" OK, but216 * still has unstable bits.217 *218 * UBI uses the @copy_flag field to indicate that this logical eraseblock is a219 * copy. UBI also calculates data CRC when the data is moved and stores it at220 * the @data_crc field of the copy (P1). So when UBI needs to pick one physical221 * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is222 * examined. If it is cleared, the situation is simple and the newer one is223 * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC224 * checksum is correct, this physical eraseblock is selected (P1). Otherwise225 * the older one (P) is selected.226 *227 * There are 2 sorts of volumes in UBI: user volumes and internal volumes.228 * Internal volumes are not seen from outside and are used for various internal229 * UBI purposes. In this implementation there is only one internal volume - the230 * layout volume. Internal volumes are the main mechanism of UBI extensions.231 * For example, in future one may introduce a journal internal volume. Internal232 * volumes have their own reserved range of IDs.233 *234 * The @compat field is only used for internal volumes and contains the "degree235 * of their compatibility". It is always zero for user volumes. This field236 * provides a mechanism to introduce UBI extensions and to be still compatible237 * with older UBI binaries. For example, if someone introduced a journal in238 * future, he would probably use %UBI_COMPAT_DELETE compatibility for the239 * journal volume. And in this case, older UBI binaries, which know nothing240 * about the journal volume, would just delete this volume and work perfectly241 * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image242 * - it just ignores the Ext3fs journal.243 *244 * The @data_crc field contains the CRC checksum of the contents of the logical245 * eraseblock if this is a static volume. In case of dynamic volumes, it does246 * not contain the CRC checksum as a rule. The only exception is when the247 * data of the physical eraseblock was moved by the wear-leveling sub-system,248 * then the wear-leveling sub-system calculates the data CRC and stores it in249 * the @data_crc field. And of course, the @copy_flag is %in this case.250 *251 * The @data_size field is used only for static volumes because UBI has to know252 * how many bytes of data are stored in this eraseblock. For dynamic volumes,253 * this field usually contains zero. The only exception is when the data of the254 * physical eraseblock was moved to another physical eraseblock for255 * wear-leveling reasons. In this case, UBI calculates CRC checksum of the256 * contents and uses both @data_crc and @data_size fields. In this case, the257 * @data_size field contains data size.258 *259 * The @used_ebs field is used only for static volumes and indicates how many260 * eraseblocks the data of the volume takes. For dynamic volumes this field is261 * not used and always contains zero.262 *263 * The @data_pad is calculated when volumes are created using the alignment264 * parameter. So, effectively, the @data_pad field reduces the size of logical265 * eraseblocks of this volume. This is very handy when one uses block-oriented266 * software (say, cramfs) on top of the UBI volume.267 */268struct ubi_vid_hdr {269 __be32 magic;270 __u8 version;271 __u8 vol_type;272 __u8 copy_flag;273 __u8 compat;274 __be32 vol_id;275 __be32 lnum;276 __u8 padding1[4];277 __be32 data_size;278 __be32 used_ebs;279 __be32 data_pad;280 __be32 data_crc;281 __u8 padding2[4];282 __be64 sqnum;283 __u8 padding3[12];284 __be32 hdr_crc;285} __packed;286 287/* Internal UBI volumes count */288#define UBI_INT_VOL_COUNT 1289 290/*291 * Starting ID of internal volumes: 0x7fffefff.292 * There is reserved room for 4096 internal volumes.293 */294#define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096)295 296/* The layout volume contains the volume table */297 298#define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START299#define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC300#define UBI_LAYOUT_VOLUME_ALIGN 1301#define UBI_LAYOUT_VOLUME_EBS 2302#define UBI_LAYOUT_VOLUME_NAME "layout volume"303#define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT304 305/* The maximum number of volumes per one UBI device */306#define UBI_MAX_VOLUMES 128307 308/* The maximum volume name length */309#define UBI_VOL_NAME_MAX 127310 311/* Size of the volume table record */312#define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record)313 314/* Size of the volume table record without the ending CRC */315#define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32))316 317/**318 * struct ubi_vtbl_record - a record in the volume table.319 * @reserved_pebs: how many physical eraseblocks are reserved for this volume320 * @alignment: volume alignment321 * @data_pad: how many bytes are unused at the end of the each physical322 * eraseblock to satisfy the requested alignment323 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)324 * @upd_marker: if volume update was started but not finished325 * @name_len: volume name length326 * @name: the volume name327 * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG)328 * @padding: reserved, zeroes329 * @crc: a CRC32 checksum of the record330 *331 * The volume table records are stored in the volume table, which is stored in332 * the layout volume. The layout volume consists of 2 logical eraseblock, each333 * of which contains a copy of the volume table (i.e., the volume table is334 * duplicated). The volume table is an array of &struct ubi_vtbl_record335 * objects indexed by the volume ID.336 *337 * If the size of the logical eraseblock is large enough to fit338 * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES339 * records. Otherwise, it contains as many records as it can fit (i.e., size of340 * logical eraseblock divided by sizeof(struct ubi_vtbl_record)).341 *342 * The @upd_marker flag is used to implement volume update. It is set to %1343 * before update and set to %0 after the update. So if the update operation was344 * interrupted, UBI knows that the volume is corrupted.345 *346 * The @alignment field is specified when the volume is created and cannot be347 * later changed. It may be useful, for example, when a block-oriented file348 * system works on top of UBI. The @data_pad field is calculated using the349 * logical eraseblock size and @alignment. The alignment must be multiple to the350 * minimal flash I/O unit. If @alignment is 1, all the available space of351 * the physical eraseblocks is used.352 *353 * Empty records contain all zeroes and the CRC checksum of those zeroes.354 */355struct ubi_vtbl_record {356 __be32 reserved_pebs;357 __be32 alignment;358 __be32 data_pad;359 __u8 vol_type;360 __u8 upd_marker;361 __be16 name_len;362 __u8 name[UBI_VOL_NAME_MAX+1];363 __u8 flags;364 __u8 padding[23];365 __be32 crc;366} __packed;367 368/* UBI fastmap on-flash data structures */369 370#define UBI_FM_SB_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 1)371#define UBI_FM_DATA_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 2)372 373/* fastmap on-flash data structure format version */374#define UBI_FM_FMT_VERSION 1375 376#define UBI_FM_SB_MAGIC 0x7B11D69F377#define UBI_FM_HDR_MAGIC 0xD4B82EF7378#define UBI_FM_VHDR_MAGIC 0xFA370ED1379#define UBI_FM_POOL_MAGIC 0x67AF4D08380#define UBI_FM_EBA_MAGIC 0xf0c040a8381 382/* A fastmap super block can be located between PEB 0 and383 * UBI_FM_MAX_START */384#define UBI_FM_MAX_START 64385 386/* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */387#define UBI_FM_MAX_BLOCKS 32388 389/* 5% of the total number of PEBs have to be scanned while attaching390 * from a fastmap.391 * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and392 * UBI_FM_MAX_POOL_SIZE */393#define UBI_FM_MIN_POOL_SIZE 8394#define UBI_FM_MAX_POOL_SIZE 256395 396/**397 * struct ubi_fm_sb - UBI fastmap super block398 * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC)399 * @version: format version of this fastmap400 * @data_crc: CRC over the fastmap data401 * @used_blocks: number of PEBs used by this fastmap402 * @block_loc: an array containing the location of all PEBs of the fastmap403 * @block_ec: the erase counter of each used PEB404 * @sqnum: highest sequence number value at the time while taking the fastmap405 *406 */407struct ubi_fm_sb {408 __be32 magic;409 __u8 version;410 __u8 padding1[3];411 __be32 data_crc;412 __be32 used_blocks;413 __be32 block_loc[UBI_FM_MAX_BLOCKS];414 __be32 block_ec[UBI_FM_MAX_BLOCKS];415 __be64 sqnum;416 __u8 padding2[32];417} __packed;418 419/**420 * struct ubi_fm_hdr - header of the fastmap data set421 * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC)422 * @free_peb_count: number of free PEBs known by this fastmap423 * @used_peb_count: number of used PEBs known by this fastmap424 * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap425 * @bad_peb_count: number of bad PEBs known by this fastmap426 * @erase_peb_count: number of bad PEBs which have to be erased427 * @vol_count: number of UBI volumes known by this fastmap428 */429struct ubi_fm_hdr {430 __be32 magic;431 __be32 free_peb_count;432 __be32 used_peb_count;433 __be32 scrub_peb_count;434 __be32 bad_peb_count;435 __be32 erase_peb_count;436 __be32 vol_count;437 __u8 padding[4];438} __packed;439 440/* struct ubi_fm_hdr is followed by two struct ubi_fm_scan_pool */441 442/**443 * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching444 * @magic: pool magic numer (%UBI_FM_POOL_MAGIC)445 * @size: current pool size446 * @max_size: maximal pool size447 * @pebs: an array containing the location of all PEBs in this pool448 */449struct ubi_fm_scan_pool {450 __be32 magic;451 __be16 size;452 __be16 max_size;453 __be32 pebs[UBI_FM_MAX_POOL_SIZE];454 __be32 padding[4];455} __packed;456 457/* ubi_fm_scan_pool is followed by nfree+nused struct ubi_fm_ec records */458 459/**460 * struct ubi_fm_ec - stores the erase counter of a PEB461 * @pnum: PEB number462 * @ec: ec of this PEB463 */464struct ubi_fm_ec {465 __be32 pnum;466 __be32 ec;467} __packed;468 469/**470 * struct ubi_fm_volhdr - Fastmap volume header471 * it identifies the start of an eba table472 * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC)473 * @vol_id: volume id of the fastmapped volume474 * @vol_type: type of the fastmapped volume475 * @data_pad: data_pad value of the fastmapped volume476 * @used_ebs: number of used LEBs within this volume477 * @last_eb_bytes: number of bytes used in the last LEB478 */479struct ubi_fm_volhdr {480 __be32 magic;481 __be32 vol_id;482 __u8 vol_type;483 __u8 padding1[3];484 __be32 data_pad;485 __be32 used_ebs;486 __be32 last_eb_bytes;487 __u8 padding2[8];488} __packed;489 490/* struct ubi_fm_volhdr is followed by one struct ubi_fm_eba records */491 492/**493 * struct ubi_fm_eba - denotes an association between a PEB and LEB494 * @magic: EBA table magic number495 * @reserved_pebs: number of table entries496 * @pnum: PEB number of LEB (LEB is the index)497 */498struct ubi_fm_eba {499 __be32 magic;500 __be32 reserved_pebs;501 __be32 pnum[];502} __packed;503#endif /* !__UBI_MEDIA_H__ */504