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