1 /* SPDX-License-Identifier: GPL-2.0+ */ 2 /* 3 * Copyright (c) International Business Machines Corp., 2006 4 * 5 * Authors: Artem Bityutskiy (Битюцкий Артём) 6 * Thomas Gleixner 7 * Frank Haverkamp 8 * Oliver Lohmann 9 * Andreas Arnez 10 */ 11 12 /* 13 * This file defines the layout of UBI headers and all the other UBI on-flash 14 * data structures. 15 */ 16 17 #ifndef __UBI_MEDIA_H__ 18 #define __UBI_MEDIA_H__ 19 20 #include <asm/byteorder.h> 21 22 /* The version of UBI images supported by this implementation */ 23 #define UBI_VERSION 1 24 25 /* The highest erase counter value supported by this implementation */ 26 #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF 27 28 /* The initial CRC32 value used when calculating CRC checksums */ 29 #define UBI_CRC32_INIT 0xFFFFFFFFU 30 31 /* Erase counter header magic number (ASCII "UBI#") */ 32 #define UBI_EC_HDR_MAGIC 0x55424923 33 /* Volume identifier header magic number (ASCII "UBI!") */ 34 #define UBI_VID_HDR_MAGIC 0x55424921 35 36 /* 37 * Volume type constants used in the volume identifier header. 38 * 39 * @UBI_VID_DYNAMIC: dynamic volume 40 * @UBI_VID_STATIC: static volume 41 */ 42 enum { 43 UBI_VID_DYNAMIC = 1, 44 UBI_VID_STATIC = 2 45 }; 46 47 /* 48 * Volume flags used in the volume table record. 49 * 50 * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume 51 * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at 52 * open time. Should only be set on volumes that 53 * are used by upper layers doing this kind of 54 * check. Main use-case for this flag is 55 * boot-time reduction 56 * 57 * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume 58 * table. UBI automatically re-sizes the volume which has this flag and makes 59 * the volume to be of largest possible size. This means that if after the 60 * initialization UBI finds out that there are available physical eraseblocks 61 * present on the device, it automatically appends all of them to the volume 62 * (the physical eraseblocks reserved for bad eraseblocks handling and other 63 * reserved physical eraseblocks are not taken). So, if there is a volume with 64 * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical 65 * eraseblocks will be zero after UBI is loaded, because all of them will be 66 * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared 67 * after the volume had been initialized. 68 * 69 * The auto-resize feature is useful for device production purposes. For 70 * example, different NAND flash chips may have different amount of initial bad 71 * eraseblocks, depending of particular chip instance. Manufacturers of NAND 72 * chips usually guarantee that the amount of initial bad eraseblocks does not 73 * exceed certain percent, e.g. 2%. When one creates an UBI image which will be 74 * flashed to the end devices in production, he does not know the exact amount 75 * of good physical eraseblocks the NAND chip on the device will have, but this 76 * number is required to calculate the volume sized and put them to the volume 77 * table of the UBI image. In this case, one of the volumes (e.g., the one 78 * which will store the root file system) is marked as "auto-resizable", and 79 * UBI will adjust its size on the first boot if needed. 80 * 81 * Note, first UBI reserves some amount of physical eraseblocks for bad 82 * eraseblock handling, and then re-sizes the volume, not vice-versa. This 83 * means that the pool of reserved physical eraseblocks will always be present. 84 */ 85 enum { 86 UBI_VTBL_AUTORESIZE_FLG = 0x01, 87 UBI_VTBL_SKIP_CRC_CHECK_FLG = 0x02, 88 }; 89 90 /* 91 * Compatibility constants used by internal volumes. 92 * 93 * @UBI_COMPAT_DELETE: delete this internal volume before anything is written 94 * to the flash 95 * @UBI_COMPAT_RO: attach this device in read-only mode 96 * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its 97 * physical eraseblocks, don't allow the wear-leveling 98 * sub-system to move them 99 * @UBI_COMPAT_REJECT: reject this UBI image 100 */ 101 enum { 102 UBI_COMPAT_DELETE = 1, 103 UBI_COMPAT_RO = 2, 104 UBI_COMPAT_PRESERVE = 4, 105 UBI_COMPAT_REJECT = 5 106 }; 107 108 /* Sizes of UBI headers */ 109 #define UBI_EC_HDR_SIZE sizeof(struct ubi_ec_hdr) 110 #define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr) 111 112 /* Sizes of UBI headers without the ending CRC */ 113 #define UBI_EC_HDR_SIZE_CRC (UBI_EC_HDR_SIZE - sizeof(__be32)) 114 #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32)) 115 116 /** 117 * struct ubi_ec_hdr - UBI erase counter header. 118 * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC) 119 * @version: version of UBI implementation which is supposed to accept this 120 * UBI image 121 * @padding1: reserved for future, zeroes 122 * @ec: the erase counter 123 * @vid_hdr_offset: where the VID header starts 124 * @data_offset: where the user data start 125 * @image_seq: image sequence number 126 * @padding2: reserved for future, zeroes 127 * @hdr_crc: erase counter header CRC checksum 128 * 129 * The erase counter header takes 64 bytes and has a plenty of unused space for 130 * future usage. The unused fields are zeroed. The @version field is used to 131 * indicate the version of UBI implementation which is supposed to be able to 132 * work with this UBI image. If @version is greater than the current UBI 133 * version, the image is rejected. This may be useful in future if something 134 * is changed radically. This field is duplicated in the volume identifier 135 * header. 136 * 137 * The @vid_hdr_offset and @data_offset fields contain the offset of the the 138 * volume identifier header and user data, relative to the beginning of the 139 * physical eraseblock. These values have to be the same for all physical 140 * eraseblocks. 141 * 142 * The @image_seq field is used to validate a UBI image that has been prepared 143 * for a UBI device. The @image_seq value can be any value, but it must be the 144 * same on all eraseblocks. UBI will ensure that all new erase counter headers 145 * also contain this value, and will check the value when attaching the flash. 146 * One way to make use of @image_seq is to increase its value by one every time 147 * an image is flashed over an existing image, then, if the flashing does not 148 * complete, UBI will detect the error when attaching the media. 149 */ 150 struct ubi_ec_hdr { 151 __be32 magic; 152 __u8 version; 153 __u8 padding1[3]; 154 __be64 ec; /* Warning: the current limit is 31-bit anyway! */ 155 __be32 vid_hdr_offset; 156 __be32 data_offset; 157 __be32 image_seq; 158 __u8 padding2[32]; 159 __be32 hdr_crc; 160 } __packed; 161 162 /** 163 * struct ubi_vid_hdr - on-flash UBI volume identifier header. 164 * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC) 165 * @version: UBI implementation version which is supposed to accept this UBI 166 * image (%UBI_VERSION) 167 * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC) 168 * @copy_flag: if this logical eraseblock was copied from another physical 169 * eraseblock (for wear-leveling reasons) 170 * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE, 171 * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT) 172 * @vol_id: ID of this volume 173 * @lnum: logical eraseblock number 174 * @padding1: reserved for future, zeroes 175 * @data_size: how many bytes of data this logical eraseblock contains 176 * @used_ebs: total number of used logical eraseblocks in this volume 177 * @data_pad: how many bytes at the end of this physical eraseblock are not 178 * used 179 * @data_crc: CRC checksum of the data stored in this logical eraseblock 180 * @padding2: reserved for future, zeroes 181 * @sqnum: sequence number 182 * @padding3: reserved for future, zeroes 183 * @hdr_crc: volume identifier header CRC checksum 184 * 185 * The @sqnum is the value of the global sequence counter at the time when this 186 * VID header was created. The global sequence counter is incremented each time 187 * UBI writes a new VID header to the flash, i.e. when it maps a logical 188 * eraseblock to a new physical eraseblock. The global sequence counter is an 189 * unsigned 64-bit integer and we assume it never overflows. The @sqnum 190 * (sequence number) is used to distinguish between older and newer versions of 191 * logical eraseblocks. 192 * 193 * There are 2 situations when there may be more than one physical eraseblock 194 * corresponding to the same logical eraseblock, i.e., having the same @vol_id 195 * and @lnum values in the volume identifier header. Suppose we have a logical 196 * eraseblock L and it is mapped to the physical eraseblock P. 197 * 198 * 1. Because UBI may erase physical eraseblocks asynchronously, the following 199 * situation is possible: L is asynchronously erased, so P is scheduled for 200 * erasure, then L is written to,i.e. mapped to another physical eraseblock P1, 201 * so P1 is written to, then an unclean reboot happens. Result - there are 2 202 * physical eraseblocks P and P1 corresponding to the same logical eraseblock 203 * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the 204 * flash. 205 * 206 * 2. From time to time UBI moves logical eraseblocks to other physical 207 * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P 208 * to P1, and an unclean reboot happens before P is physically erased, there 209 * are two physical eraseblocks P and P1 corresponding to L and UBI has to 210 * select one of them when the flash is attached. The @sqnum field says which 211 * PEB is the original (obviously P will have lower @sqnum) and the copy. But 212 * it is not enough to select the physical eraseblock with the higher sequence 213 * number, because the unclean reboot could have happen in the middle of the 214 * copying process, so the data in P is corrupted. It is also not enough to 215 * just select the physical eraseblock with lower sequence number, because the 216 * data there may be old (consider a case if more data was added to P1 after 217 * the copying). Moreover, the unclean reboot may happen when the erasure of P 218 * was just started, so it result in unstable P, which is "mostly" OK, but 219 * still has unstable bits. 220 * 221 * UBI uses the @copy_flag field to indicate that this logical eraseblock is a 222 * copy. UBI also calculates data CRC when the data is moved and stores it at 223 * the @data_crc field of the copy (P1). So when UBI needs to pick one physical 224 * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is 225 * examined. If it is cleared, the situation* is simple and the newer one is 226 * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC 227 * checksum is correct, this physical eraseblock is selected (P1). Otherwise 228 * the older one (P) is selected. 229 * 230 * There are 2 sorts of volumes in UBI: user volumes and internal volumes. 231 * Internal volumes are not seen from outside and are used for various internal 232 * UBI purposes. In this implementation there is only one internal volume - the 233 * layout volume. Internal volumes are the main mechanism of UBI extensions. 234 * For example, in future one may introduce a journal internal volume. Internal 235 * volumes have their own reserved range of IDs. 236 * 237 * The @compat field is only used for internal volumes and contains the "degree 238 * of their compatibility". It is always zero for user volumes. This field 239 * provides a mechanism to introduce UBI extensions and to be still compatible 240 * with older UBI binaries. For example, if someone introduced a journal in 241 * future, he would probably use %UBI_COMPAT_DELETE compatibility for the 242 * journal volume. And in this case, older UBI binaries, which know nothing 243 * about the journal volume, would just delete this volume and work perfectly 244 * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image 245 * - it just ignores the Ext3fs journal. 246 * 247 * The @data_crc field contains the CRC checksum of the contents of the logical 248 * eraseblock if this is a static volume. In case of dynamic volumes, it does 249 * not contain the CRC checksum as a rule. The only exception is when the 250 * data of the physical eraseblock was moved by the wear-leveling sub-system, 251 * then the wear-leveling sub-system calculates the data CRC and stores it in 252 * the @data_crc field. And of course, the @copy_flag is %in this case. 253 * 254 * The @data_size field is used only for static volumes because UBI has to know 255 * how many bytes of data are stored in this eraseblock. For dynamic volumes, 256 * this field usually contains zero. The only exception is when the data of the 257 * physical eraseblock was moved to another physical eraseblock for 258 * wear-leveling reasons. In this case, UBI calculates CRC checksum of the 259 * contents and uses both @data_crc and @data_size fields. In this case, the 260 * @data_size field contains data size. 261 * 262 * The @used_ebs field is used only for static volumes and indicates how many 263 * eraseblocks the data of the volume takes. For dynamic volumes this field is 264 * not used and always contains zero. 265 * 266 * The @data_pad is calculated when volumes are created using the alignment 267 * parameter. So, effectively, the @data_pad field reduces the size of logical 268 * eraseblocks of this volume. This is very handy when one uses block-oriented 269 * software (say, cramfs) on top of the UBI volume. 270 */ 271 struct ubi_vid_hdr { 272 __be32 magic; 273 __u8 version; 274 __u8 vol_type; 275 __u8 copy_flag; 276 __u8 compat; 277 __be32 vol_id; 278 __be32 lnum; 279 __u8 padding1[4]; 280 __be32 data_size; 281 __be32 used_ebs; 282 __be32 data_pad; 283 __be32 data_crc; 284 __u8 padding2[4]; 285 __be64 sqnum; 286 __u8 padding3[12]; 287 __be32 hdr_crc; 288 } __packed; 289 290 /* Internal UBI volumes count */ 291 #define UBI_INT_VOL_COUNT 1 292 293 /* 294 * Starting ID of internal volumes: 0x7fffefff. 295 * There is reserved room for 4096 internal volumes. 296 */ 297 #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096) 298 299 /* The layout volume contains the volume table */ 300 301 #define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START 302 #define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC 303 #define UBI_LAYOUT_VOLUME_ALIGN 1 304 #define UBI_LAYOUT_VOLUME_EBS 2 305 #define UBI_LAYOUT_VOLUME_NAME "layout volume" 306 #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT 307 308 /* The maximum number of volumes per one UBI device */ 309 #define UBI_MAX_VOLUMES 128 310 311 /* The maximum volume name length */ 312 #define UBI_VOL_NAME_MAX 127 313 314 /* Size of the volume table record */ 315 #define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record) 316 317 /* Size of the volume table record without the ending CRC */ 318 #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32)) 319 320 /** 321 * struct ubi_vtbl_record - a record in the volume table. 322 * @reserved_pebs: how many physical eraseblocks are reserved for this volume 323 * @alignment: volume alignment 324 * @data_pad: how many bytes are unused at the end of the each physical 325 * eraseblock to satisfy the requested alignment 326 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) 327 * @upd_marker: if volume update was started but not finished 328 * @name_len: volume name length 329 * @name: the volume name 330 * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG) 331 * @padding: reserved, zeroes 332 * @crc: a CRC32 checksum of the record 333 * 334 * The volume table records are stored in the volume table, which is stored in 335 * the layout volume. The layout volume consists of 2 logical eraseblock, each 336 * of which contains a copy of the volume table (i.e., the volume table is 337 * duplicated). The volume table is an array of &struct ubi_vtbl_record 338 * objects indexed by the volume ID. 339 * 340 * If the size of the logical eraseblock is large enough to fit 341 * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES 342 * records. Otherwise, it contains as many records as it can fit (i.e., size of 343 * logical eraseblock divided by sizeof(struct ubi_vtbl_record)). 344 * 345 * The @upd_marker flag is used to implement volume update. It is set to %1 346 * before update and set to %0 after the update. So if the update operation was 347 * interrupted, UBI knows that the volume is corrupted. 348 * 349 * The @alignment field is specified when the volume is created and cannot be 350 * later changed. It may be useful, for example, when a block-oriented file 351 * system works on top of UBI. The @data_pad field is calculated using the 352 * logical eraseblock size and @alignment. The alignment must be multiple to the 353 * minimal flash I/O unit. If @alignment is 1, all the available space of 354 * the physical eraseblocks is used. 355 * 356 * Empty records contain all zeroes and the CRC checksum of those zeroes. 357 */ 358 struct ubi_vtbl_record { 359 __be32 reserved_pebs; 360 __be32 alignment; 361 __be32 data_pad; 362 __u8 vol_type; 363 __u8 upd_marker; 364 __be16 name_len; 365 #ifndef __UBOOT__ 366 __u8 name[UBI_VOL_NAME_MAX+1]; 367 #else 368 char name[UBI_VOL_NAME_MAX+1]; 369 #endif 370 __u8 flags; 371 __u8 padding[23]; 372 __be32 crc; 373 } __packed; 374 375 /* UBI fastmap on-flash data structures */ 376 377 #define UBI_FM_SB_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 1) 378 #define UBI_FM_DATA_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 2) 379 380 /* fastmap on-flash data structure format version */ 381 #define UBI_FM_FMT_VERSION 1 382 383 #define UBI_FM_SB_MAGIC 0x7B11D69F 384 #define UBI_FM_HDR_MAGIC 0xD4B82EF7 385 #define UBI_FM_VHDR_MAGIC 0xFA370ED1 386 #define UBI_FM_POOL_MAGIC 0x67AF4D08 387 #define UBI_FM_EBA_MAGIC 0xf0c040a8 388 389 /* A fastmap supber block can be located between PEB 0 and 390 * UBI_FM_MAX_START */ 391 #define UBI_FM_MAX_START 64 392 393 /* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */ 394 #define UBI_FM_MAX_BLOCKS 32 395 396 /* 5% of the total number of PEBs have to be scanned while attaching 397 * from a fastmap. 398 * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and 399 * UBI_FM_MAX_POOL_SIZE */ 400 #define UBI_FM_MIN_POOL_SIZE 8 401 #define UBI_FM_MAX_POOL_SIZE 256 402 403 /** 404 * struct ubi_fm_sb - UBI fastmap super block 405 * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC) 406 * @version: format version of this fastmap 407 * @data_crc: CRC over the fastmap data 408 * @used_blocks: number of PEBs used by this fastmap 409 * @block_loc: an array containing the location of all PEBs of the fastmap 410 * @block_ec: the erase counter of each used PEB 411 * @sqnum: highest sequence number value at the time while taking the fastmap 412 * 413 */ 414 struct ubi_fm_sb { 415 __be32 magic; 416 __u8 version; 417 __u8 padding1[3]; 418 __be32 data_crc; 419 __be32 used_blocks; 420 __be32 block_loc[UBI_FM_MAX_BLOCKS]; 421 __be32 block_ec[UBI_FM_MAX_BLOCKS]; 422 __be64 sqnum; 423 __u8 padding2[32]; 424 } __packed; 425 426 /** 427 * struct ubi_fm_hdr - header of the fastmap data set 428 * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC) 429 * @free_peb_count: number of free PEBs known by this fastmap 430 * @used_peb_count: number of used PEBs known by this fastmap 431 * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap 432 * @bad_peb_count: number of bad PEBs known by this fastmap 433 * @erase_peb_count: number of bad PEBs which have to be erased 434 * @vol_count: number of UBI volumes known by this fastmap 435 */ 436 struct ubi_fm_hdr { 437 __be32 magic; 438 __be32 free_peb_count; 439 __be32 used_peb_count; 440 __be32 scrub_peb_count; 441 __be32 bad_peb_count; 442 __be32 erase_peb_count; 443 __be32 vol_count; 444 __u8 padding[4]; 445 } __packed; 446 447 /* struct ubi_fm_hdr is followed by two struct ubi_fm_scan_pool */ 448 449 /** 450 * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching 451 * @magic: pool magic numer (%UBI_FM_POOL_MAGIC) 452 * @size: current pool size 453 * @max_size: maximal pool size 454 * @pebs: an array containing the location of all PEBs in this pool 455 */ 456 struct ubi_fm_scan_pool { 457 __be32 magic; 458 __be16 size; 459 __be16 max_size; 460 __be32 pebs[UBI_FM_MAX_POOL_SIZE]; 461 __be32 padding[4]; 462 } __packed; 463 464 /* ubi_fm_scan_pool is followed by nfree+nused struct ubi_fm_ec records */ 465 466 /** 467 * struct ubi_fm_ec - stores the erase counter of a PEB 468 * @pnum: PEB number 469 * @ec: ec of this PEB 470 */ 471 struct ubi_fm_ec { 472 __be32 pnum; 473 __be32 ec; 474 } __packed; 475 476 /** 477 * struct ubi_fm_volhdr - Fastmap volume header 478 * it identifies the start of an eba table 479 * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC) 480 * @vol_id: volume id of the fastmapped volume 481 * @vol_type: type of the fastmapped volume 482 * @data_pad: data_pad value of the fastmapped volume 483 * @used_ebs: number of used LEBs within this volume 484 * @last_eb_bytes: number of bytes used in the last LEB 485 */ 486 struct ubi_fm_volhdr { 487 __be32 magic; 488 __be32 vol_id; 489 __u8 vol_type; 490 __u8 padding1[3]; 491 __be32 data_pad; 492 __be32 used_ebs; 493 __be32 last_eb_bytes; 494 __u8 padding2[8]; 495 } __packed; 496 497 /* struct ubi_fm_volhdr is followed by one struct ubi_fm_eba records */ 498 499 /** 500 * struct ubi_fm_eba - denotes an association beween a PEB and LEB 501 * @magic: EBA table magic number 502 * @reserved_pebs: number of table entries 503 * @pnum: PEB number of LEB (LEB is the index) 504 */ 505 struct ubi_fm_eba { 506 __be32 magic; 507 __be32 reserved_pebs; 508 __be32 pnum[0]; 509 } __packed; 510 #endif /* !__UBI_MEDIA_H__ */ 511