1 /* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */ 2 /* 3 * Copyright (C) International Business Machines Corp., 2006 4 * Authors: Artem Bityutskiy (Битюцкий Артём) 5 * Thomas Gleixner 6 * Frank Haverkamp 7 * Oliver Lohmann 8 * Andreas Arnez 9 * 10 * This file defines the layout of UBI headers and all the other UBI on-flash 11 * 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 1 21 22 /* The highest erase counter value supported by this implementation */ 23 #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF 24 25 /* The initial CRC32 value used when calculating CRC checksums */ 26 #define UBI_CRC32_INIT 0xFFFFFFFFU 27 28 /* Erase counter header magic number (ASCII "UBI#") */ 29 #define UBI_EC_HDR_MAGIC 0x55424923 30 /* Volume identifier header magic number (ASCII "UBI!") */ 31 #define UBI_VID_HDR_MAGIC 0x55424921 32 33 /* 34 * Volume type constants used in the volume identifier header. 35 * 36 * @UBI_VID_DYNAMIC: dynamic volume 37 * @UBI_VID_STATIC: static volume 38 */ 39 enum { 40 UBI_VID_DYNAMIC = 1, 41 UBI_VID_STATIC = 2 42 }; 43 44 /* 45 * Volume flags used in the volume table record. 46 * 47 * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume 48 * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at 49 * open time. Should only be set on volumes that 50 * are used by upper layers doing this kind of 51 * check. Main use-case for this flag is 52 * boot-time reduction 53 * 54 * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume 55 * table. UBI automatically re-sizes the volume which has this flag and makes 56 * the volume to be of largest possible size. This means that if after the 57 * initialization UBI finds out that there are available physical eraseblocks 58 * present on the device, it automatically appends all of them to the volume 59 * (the physical eraseblocks reserved for bad eraseblocks handling and other 60 * reserved physical eraseblocks are not taken). So, if there is a volume with 61 * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical 62 * eraseblocks will be zero after UBI is loaded, because all of them will be 63 * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared 64 * after the volume had been initialized. 65 * 66 * The auto-resize feature is useful for device production purposes. For 67 * example, different NAND flash chips may have different amount of initial bad 68 * eraseblocks, depending of particular chip instance. Manufacturers of NAND 69 * chips usually guarantee that the amount of initial bad eraseblocks does not 70 * exceed certain percent, e.g. 2%. When one creates an UBI image which will be 71 * flashed to the end devices in production, he does not know the exact amount 72 * of good physical eraseblocks the NAND chip on the device will have, but this 73 * number is required to calculate the volume sized and put them to the volume 74 * table of the UBI image. In this case, one of the volumes (e.g., the one 75 * which will store the root file system) is marked as "auto-resizable", and 76 * UBI will adjust its size on the first boot if needed. 77 * 78 * Note, first UBI reserves some amount of physical eraseblocks for bad 79 * eraseblock handling, and then re-sizes the volume, not vice-versa. This 80 * means that the pool of reserved physical eraseblocks will always be present. 81 */ 82 enum { 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 written 91 * to the flash 92 * @UBI_COMPAT_RO: attach this device in read-only mode 93 * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its 94 * physical eraseblocks, don't allow the wear-leveling 95 * sub-system to move them 96 * @UBI_COMPAT_REJECT: reject this UBI image 97 */ 98 enum { 99 UBI_COMPAT_DELETE = 1, 100 UBI_COMPAT_RO = 2, 101 UBI_COMPAT_PRESERVE = 4, 102 UBI_COMPAT_REJECT = 5 103 }; 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 this 117 * UBI image 118 * @padding1: reserved for future, zeroes 119 * @ec: the erase counter 120 * @vid_hdr_offset: where the VID header starts 121 * @data_offset: where the user data start 122 * @image_seq: image sequence number 123 * @padding2: reserved for future, zeroes 124 * @hdr_crc: erase counter header CRC checksum 125 * 126 * The erase counter header takes 64 bytes and has a plenty of unused space for 127 * future usage. The unused fields are zeroed. The @version field is used to 128 * indicate the version of UBI implementation which is supposed to be able to 129 * work with this UBI image. If @version is greater than the current UBI 130 * version, the image is rejected. This may be useful in future if something 131 * is changed radically. This field is duplicated in the volume identifier 132 * header. 133 * 134 * The @vid_hdr_offset and @data_offset fields contain the offset of the the 135 * volume identifier header and user data, relative to the beginning of the 136 * physical eraseblock. These values have to be the same for all physical 137 * eraseblocks. 138 * 139 * The @image_seq field is used to validate a UBI image that has been prepared 140 * for a UBI device. The @image_seq value can be any value, but it must be the 141 * same on all eraseblocks. UBI will ensure that all new erase counter headers 142 * 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 time 144 * an image is flashed over an existing image, then, if the flashing does not 145 * complete, UBI will detect the error when attaching the media. 146 */ 147 struct 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 UBI 163 * 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 physical 166 * 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 volume 170 * @lnum: logical eraseblock number 171 * @padding1: reserved for future, zeroes 172 * @data_size: how many bytes of data this logical eraseblock contains 173 * @used_ebs: total number of used logical eraseblocks in this volume 174 * @data_pad: how many bytes at the end of this physical eraseblock are not 175 * used 176 * @data_crc: CRC checksum of the data stored in this logical eraseblock 177 * @padding2: reserved for future, zeroes 178 * @sqnum: sequence number 179 * @padding3: reserved for future, zeroes 180 * @hdr_crc: volume identifier header CRC checksum 181 * 182 * The @sqnum is the value of the global sequence counter at the time when this 183 * VID header was created. The global sequence counter is incremented each time 184 * UBI writes a new VID header to the flash, i.e. when it maps a logical 185 * eraseblock to a new physical eraseblock. The global sequence counter is an 186 * unsigned 64-bit integer and we assume it never overflows. The @sqnum 187 * (sequence number) is used to distinguish between older and newer versions of 188 * logical eraseblocks. 189 * 190 * There are 2 situations when there may be more than one physical eraseblock 191 * corresponding to the same logical eraseblock, i.e., having the same @vol_id 192 * and @lnum values in the volume identifier header. Suppose we have a logical 193 * eraseblock L and it is mapped to the physical eraseblock P. 194 * 195 * 1. Because UBI may erase physical eraseblocks asynchronously, the following 196 * situation is possible: L is asynchronously erased, so P is scheduled for 197 * 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 2 199 * physical eraseblocks P and P1 corresponding to the same logical eraseblock 200 * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the 201 * flash. 202 * 203 * 2. From time to time UBI moves logical eraseblocks to other physical 204 * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P 205 * to P1, and an unclean reboot happens before P is physically erased, there 206 * are two physical eraseblocks P and P1 corresponding to L and UBI has to 207 * select one of them when the flash is attached. The @sqnum field says which 208 * PEB is the original (obviously P will have lower @sqnum) and the copy. But 209 * it is not enough to select the physical eraseblock with the higher sequence 210 * number, because the unclean reboot could have happen in the middle of the 211 * copying process, so the data in P is corrupted. It is also not enough to 212 * just select the physical eraseblock with lower sequence number, because the 213 * data there may be old (consider a case if more data was added to P1 after 214 * the copying). Moreover, the unclean reboot may happen when the erasure of P 215 * was just started, so it result in unstable P, which is "mostly" OK, but 216 * still has unstable bits. 217 * 218 * UBI uses the @copy_flag field to indicate that this logical eraseblock is a 219 * copy. UBI also calculates data CRC when the data is moved and stores it at 220 * the @data_crc field of the copy (P1). So when UBI needs to pick one physical 221 * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is 222 * examined. If it is cleared, the situation is simple and the newer one is 223 * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC 224 * checksum is correct, this physical eraseblock is selected (P1). Otherwise 225 * 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 internal 229 * UBI purposes. In this implementation there is only one internal volume - the 230 * layout volume. Internal volumes are the main mechanism of UBI extensions. 231 * For example, in future one may introduce a journal internal volume. Internal 232 * volumes have their own reserved range of IDs. 233 * 234 * The @compat field is only used for internal volumes and contains the "degree 235 * of their compatibility". It is always zero for user volumes. This field 236 * provides a mechanism to introduce UBI extensions and to be still compatible 237 * with older UBI binaries. For example, if someone introduced a journal in 238 * future, he would probably use %UBI_COMPAT_DELETE compatibility for the 239 * journal volume. And in this case, older UBI binaries, which know nothing 240 * about the journal volume, would just delete this volume and work perfectly 241 * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image 242 * - it just ignores the Ext3fs journal. 243 * 244 * The @data_crc field contains the CRC checksum of the contents of the logical 245 * eraseblock if this is a static volume. In case of dynamic volumes, it does 246 * not contain the CRC checksum as a rule. The only exception is when the 247 * 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 in 249 * 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 know 252 * 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 the 254 * physical eraseblock was moved to another physical eraseblock for 255 * wear-leveling reasons. In this case, UBI calculates CRC checksum of the 256 * contents and uses both @data_crc and @data_size fields. In this case, the 257 * @data_size field contains data size. 258 * 259 * The @used_ebs field is used only for static volumes and indicates how many 260 * eraseblocks the data of the volume takes. For dynamic volumes this field is 261 * not used and always contains zero. 262 * 263 * The @data_pad is calculated when volumes are created using the alignment 264 * parameter. So, effectively, the @data_pad field reduces the size of logical 265 * eraseblocks of this volume. This is very handy when one uses block-oriented 266 * software (say, cramfs) on top of the UBI volume. 267 */ 268 struct 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 1 289 290 /* 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_START 299 #define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC 300 #define UBI_LAYOUT_VOLUME_ALIGN 1 301 #define UBI_LAYOUT_VOLUME_EBS 2 302 #define UBI_LAYOUT_VOLUME_NAME "layout volume" 303 #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT 304 305 /* The maximum number of volumes per one UBI device */ 306 #define UBI_MAX_VOLUMES 128 307 308 /* The maximum volume name length */ 309 #define UBI_VOL_NAME_MAX 127 310 311 /* 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 volume 320 * @alignment: volume alignment 321 * @data_pad: how many bytes are unused at the end of the each physical 322 * eraseblock to satisfy the requested alignment 323 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) 324 * @upd_marker: if volume update was started but not finished 325 * @name_len: volume name length 326 * @name: the volume name 327 * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG) 328 * @padding: reserved, zeroes 329 * @crc: a CRC32 checksum of the record 330 * 331 * The volume table records are stored in the volume table, which is stored in 332 * the layout volume. The layout volume consists of 2 logical eraseblock, each 333 * of which contains a copy of the volume table (i.e., the volume table is 334 * duplicated). The volume table is an array of &struct ubi_vtbl_record 335 * objects indexed by the volume ID. 336 * 337 * If the size of the logical eraseblock is large enough to fit 338 * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES 339 * records. Otherwise, it contains as many records as it can fit (i.e., size of 340 * 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 %1 343 * before update and set to %0 after the update. So if the update operation was 344 * interrupted, UBI knows that the volume is corrupted. 345 * 346 * The @alignment field is specified when the volume is created and cannot be 347 * later changed. It may be useful, for example, when a block-oriented file 348 * system works on top of UBI. The @data_pad field is calculated using the 349 * logical eraseblock size and @alignment. The alignment must be multiple to the 350 * minimal flash I/O unit. If @alignment is 1, all the available space of 351 * the physical eraseblocks is used. 352 * 353 * Empty records contain all zeroes and the CRC checksum of those zeroes. 354 */ 355 struct 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 1 375 376 #define UBI_FM_SB_MAGIC 0x7B11D69F 377 #define UBI_FM_HDR_MAGIC 0xD4B82EF7 378 #define UBI_FM_VHDR_MAGIC 0xFA370ED1 379 #define UBI_FM_POOL_MAGIC 0x67AF4D08 380 #define UBI_FM_EBA_MAGIC 0xf0c040a8 381 382 /* A fastmap super block can be located between PEB 0 and 383 * UBI_FM_MAX_START */ 384 #define UBI_FM_MAX_START 64 385 386 /* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */ 387 #define UBI_FM_MAX_BLOCKS 32 388 389 /* 5% of the total number of PEBs have to be scanned while attaching 390 * from a fastmap. 391 * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and 392 * UBI_FM_MAX_POOL_SIZE */ 393 #define UBI_FM_MIN_POOL_SIZE 8 394 #define UBI_FM_MAX_POOL_SIZE 256 395 396 /** 397 * struct ubi_fm_sb - UBI fastmap super block 398 * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC) 399 * @version: format version of this fastmap 400 * @data_crc: CRC over the fastmap data 401 * @used_blocks: number of PEBs used by this fastmap 402 * @block_loc: an array containing the location of all PEBs of the fastmap 403 * @block_ec: the erase counter of each used PEB 404 * @sqnum: highest sequence number value at the time while taking the fastmap 405 * 406 */ 407 struct 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 set 421 * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC) 422 * @free_peb_count: number of free PEBs known by this fastmap 423 * @used_peb_count: number of used PEBs known by this fastmap 424 * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap 425 * @bad_peb_count: number of bad PEBs known by this fastmap 426 * @erase_peb_count: number of bad PEBs which have to be erased 427 * @vol_count: number of UBI volumes known by this fastmap 428 */ 429 struct 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 attaching 444 * @magic: pool magic numer (%UBI_FM_POOL_MAGIC) 445 * @size: current pool size 446 * @max_size: maximal pool size 447 * @pebs: an array containing the location of all PEBs in this pool 448 */ 449 struct 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 PEB 461 * @pnum: PEB number 462 * @ec: ec of this PEB 463 */ 464 struct ubi_fm_ec { 465 __be32 pnum; 466 __be32 ec; 467 } __packed; 468 469 /** 470 * struct ubi_fm_volhdr - Fastmap volume header 471 * it identifies the start of an eba table 472 * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC) 473 * @vol_id: volume id of the fastmapped volume 474 * @vol_type: type of the fastmapped volume 475 * @data_pad: data_pad value of the fastmapped volume 476 * @used_ebs: number of used LEBs within this volume 477 * @last_eb_bytes: number of bytes used in the last LEB 478 */ 479 struct 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 LEB 494 * @magic: EBA table magic number 495 * @reserved_pebs: number of table entries 496 * @pnum: PEB number of LEB (LEB is the index) 497 */ 498 struct ubi_fm_eba { 499 __be32 magic; 500 __be32 reserved_pebs; 501 __be32 pnum[0]; 502 } __packed; 503 #endif /* !__UBI_MEDIA_H__ */ 504