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