1 /* 2 * Copyright (c) International Business Machines Corp., 2006 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 12 * the GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Authors: Artem Bityutskiy (Битюцкий Артём) 19 * Thomas Gleixner 20 * Frank Haverkamp 21 * Oliver Lohmann 22 * Andreas Arnez 23 */ 24 25 /* 26 * This file defines the layout of UBI headers and all the other UBI on-flash 27 * data structures. 28 */ 29 30 #ifndef __UBI_MEDIA_H__ 31 #define __UBI_MEDIA_H__ 32 33 #include <asm/byteorder.h> 34 35 /* The version of UBI images supported by this implementation */ 36 #define UBI_VERSION 1 37 38 /* The highest erase counter value supported by this implementation */ 39 #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF 40 41 /* The initial CRC32 value used when calculating CRC checksums */ 42 #define UBI_CRC32_INIT 0xFFFFFFFFU 43 44 /* Erase counter header magic number (ASCII "UBI#") */ 45 #define UBI_EC_HDR_MAGIC 0x55424923 46 /* Volume identifier header magic number (ASCII "UBI!") */ 47 #define UBI_VID_HDR_MAGIC 0x55424921 48 49 /* 50 * Volume type constants used in the volume identifier header. 51 * 52 * @UBI_VID_DYNAMIC: dynamic volume 53 * @UBI_VID_STATIC: static volume 54 */ 55 enum { 56 UBI_VID_DYNAMIC = 1, 57 UBI_VID_STATIC = 2 58 }; 59 60 /* 61 * Volume flags used in the volume table record. 62 * 63 * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume 64 * 65 * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume 66 * table. UBI automatically re-sizes the volume which has this flag and makes 67 * the volume to be of largest possible size. This means that if after the 68 * initialization UBI finds out that there are available physical eraseblocks 69 * present on the device, it automatically appends all of them to the volume 70 * (the physical eraseblocks reserved for bad eraseblocks handling and other 71 * reserved physical eraseblocks are not taken). So, if there is a volume with 72 * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical 73 * eraseblocks will be zero after UBI is loaded, because all of them will be 74 * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared 75 * after the volume had been initialized. 76 * 77 * The auto-resize feature is useful for device production purposes. For 78 * example, different NAND flash chips may have different amount of initial bad 79 * eraseblocks, depending of particular chip instance. Manufacturers of NAND 80 * chips usually guarantee that the amount of initial bad eraseblocks does not 81 * exceed certain percent, e.g. 2%. When one creates an UBI image which will be 82 * flashed to the end devices in production, he does not know the exact amount 83 * of good physical eraseblocks the NAND chip on the device will have, but this 84 * number is required to calculate the volume sized and put them to the volume 85 * table of the UBI image. In this case, one of the volumes (e.g., the one 86 * which will store the root file system) is marked as "auto-resizable", and 87 * UBI will adjust its size on the first boot if needed. 88 * 89 * Note, first UBI reserves some amount of physical eraseblocks for bad 90 * eraseblock handling, and then re-sizes the volume, not vice-versa. This 91 * means that the pool of reserved physical eraseblocks will always be present. 92 */ 93 enum { 94 UBI_VTBL_AUTORESIZE_FLG = 0x01, 95 }; 96 97 /* 98 * Compatibility constants used by internal volumes. 99 * 100 * @UBI_COMPAT_DELETE: delete this internal volume before anything is written 101 * to the flash 102 * @UBI_COMPAT_RO: attach this device in read-only mode 103 * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its 104 * physical eraseblocks, don't allow the wear-leveling 105 * sub-system to move them 106 * @UBI_COMPAT_REJECT: reject this UBI image 107 */ 108 enum { 109 UBI_COMPAT_DELETE = 1, 110 UBI_COMPAT_RO = 2, 111 UBI_COMPAT_PRESERVE = 4, 112 UBI_COMPAT_REJECT = 5 113 }; 114 115 /* Sizes of UBI headers */ 116 #define UBI_EC_HDR_SIZE sizeof(struct ubi_ec_hdr) 117 #define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr) 118 119 /* Sizes of UBI headers without the ending CRC */ 120 #define UBI_EC_HDR_SIZE_CRC (UBI_EC_HDR_SIZE - sizeof(__be32)) 121 #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32)) 122 123 /** 124 * struct ubi_ec_hdr - UBI erase counter header. 125 * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC) 126 * @version: version of UBI implementation which is supposed to accept this 127 * UBI image 128 * @padding1: reserved for future, zeroes 129 * @ec: the erase counter 130 * @vid_hdr_offset: where the VID header starts 131 * @data_offset: where the user data start 132 * @image_seq: image sequence number 133 * @padding2: reserved for future, zeroes 134 * @hdr_crc: erase counter header CRC checksum 135 * 136 * The erase counter header takes 64 bytes and has a plenty of unused space for 137 * future usage. The unused fields are zeroed. The @version field is used to 138 * indicate the version of UBI implementation which is supposed to be able to 139 * work with this UBI image. If @version is greater than the current UBI 140 * version, the image is rejected. This may be useful in future if something 141 * is changed radically. This field is duplicated in the volume identifier 142 * header. 143 * 144 * The @vid_hdr_offset and @data_offset fields contain the offset of the the 145 * volume identifier header and user data, relative to the beginning of the 146 * physical eraseblock. These values have to be the same for all physical 147 * eraseblocks. 148 * 149 * The @image_seq field is used to validate a UBI image that has been prepared 150 * for a UBI device. The @image_seq value can be any value, but it must be the 151 * same on all eraseblocks. UBI will ensure that all new erase counter headers 152 * also contain this value, and will check the value when attaching the flash. 153 * One way to make use of @image_seq is to increase its value by one every time 154 * an image is flashed over an existing image, then, if the flashing does not 155 * complete, UBI will detect the error when attaching the media. 156 */ 157 struct ubi_ec_hdr { 158 __be32 magic; 159 __u8 version; 160 __u8 padding1[3]; 161 __be64 ec; /* Warning: the current limit is 31-bit anyway! */ 162 __be32 vid_hdr_offset; 163 __be32 data_offset; 164 __be32 image_seq; 165 __u8 padding2[32]; 166 __be32 hdr_crc; 167 } __packed; 168 169 /** 170 * struct ubi_vid_hdr - on-flash UBI volume identifier header. 171 * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC) 172 * @version: UBI implementation version which is supposed to accept this UBI 173 * image (%UBI_VERSION) 174 * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC) 175 * @copy_flag: if this logical eraseblock was copied from another physical 176 * eraseblock (for wear-leveling reasons) 177 * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE, 178 * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT) 179 * @vol_id: ID of this volume 180 * @lnum: logical eraseblock number 181 * @padding1: reserved for future, zeroes 182 * @data_size: how many bytes of data this logical eraseblock contains 183 * @used_ebs: total number of used logical eraseblocks in this volume 184 * @data_pad: how many bytes at the end of this physical eraseblock are not 185 * used 186 * @data_crc: CRC checksum of the data stored in this logical eraseblock 187 * @padding2: reserved for future, zeroes 188 * @sqnum: sequence number 189 * @padding3: reserved for future, zeroes 190 * @hdr_crc: volume identifier header CRC checksum 191 * 192 * The @sqnum is the value of the global sequence counter at the time when this 193 * VID header was created. The global sequence counter is incremented each time 194 * UBI writes a new VID header to the flash, i.e. when it maps a logical 195 * eraseblock to a new physical eraseblock. The global sequence counter is an 196 * unsigned 64-bit integer and we assume it never overflows. The @sqnum 197 * (sequence number) is used to distinguish between older and newer versions of 198 * logical eraseblocks. 199 * 200 * There are 2 situations when there may be more than one physical eraseblock 201 * corresponding to the same logical eraseblock, i.e., having the same @vol_id 202 * and @lnum values in the volume identifier header. Suppose we have a logical 203 * eraseblock L and it is mapped to the physical eraseblock P. 204 * 205 * 1. Because UBI may erase physical eraseblocks asynchronously, the following 206 * situation is possible: L is asynchronously erased, so P is scheduled for 207 * erasure, then L is written to,i.e. mapped to another physical eraseblock P1, 208 * so P1 is written to, then an unclean reboot happens. Result - there are 2 209 * physical eraseblocks P and P1 corresponding to the same logical eraseblock 210 * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the 211 * flash. 212 * 213 * 2. From time to time UBI moves logical eraseblocks to other physical 214 * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P 215 * to P1, and an unclean reboot happens before P is physically erased, there 216 * are two physical eraseblocks P and P1 corresponding to L and UBI has to 217 * select one of them when the flash is attached. The @sqnum field says which 218 * PEB is the original (obviously P will have lower @sqnum) and the copy. But 219 * it is not enough to select the physical eraseblock with the higher sequence 220 * number, because the unclean reboot could have happen in the middle of the 221 * copying process, so the data in P is corrupted. It is also not enough to 222 * just select the physical eraseblock with lower sequence number, because the 223 * data there may be old (consider a case if more data was added to P1 after 224 * the copying). Moreover, the unclean reboot may happen when the erasure of P 225 * was just started, so it result in unstable P, which is "mostly" OK, but 226 * still has unstable bits. 227 * 228 * UBI uses the @copy_flag field to indicate that this logical eraseblock is a 229 * copy. UBI also calculates data CRC when the data is moved and stores it at 230 * the @data_crc field of the copy (P1). So when UBI needs to pick one physical 231 * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is 232 * examined. If it is cleared, the situation* is simple and the newer one is 233 * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC 234 * checksum is correct, this physical eraseblock is selected (P1). Otherwise 235 * the older one (P) is selected. 236 * 237 * There are 2 sorts of volumes in UBI: user volumes and internal volumes. 238 * Internal volumes are not seen from outside and are used for various internal 239 * UBI purposes. In this implementation there is only one internal volume - the 240 * layout volume. Internal volumes are the main mechanism of UBI extensions. 241 * For example, in future one may introduce a journal internal volume. Internal 242 * volumes have their own reserved range of IDs. 243 * 244 * The @compat field is only used for internal volumes and contains the "degree 245 * of their compatibility". It is always zero for user volumes. This field 246 * provides a mechanism to introduce UBI extensions and to be still compatible 247 * with older UBI binaries. For example, if someone introduced a journal in 248 * future, he would probably use %UBI_COMPAT_DELETE compatibility for the 249 * journal volume. And in this case, older UBI binaries, which know nothing 250 * about the journal volume, would just delete this volume and work perfectly 251 * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image 252 * - it just ignores the Ext3fs journal. 253 * 254 * The @data_crc field contains the CRC checksum of the contents of the logical 255 * eraseblock if this is a static volume. In case of dynamic volumes, it does 256 * not contain the CRC checksum as a rule. The only exception is when the 257 * data of the physical eraseblock was moved by the wear-leveling sub-system, 258 * then the wear-leveling sub-system calculates the data CRC and stores it in 259 * the @data_crc field. And of course, the @copy_flag is %in this case. 260 * 261 * The @data_size field is used only for static volumes because UBI has to know 262 * how many bytes of data are stored in this eraseblock. For dynamic volumes, 263 * this field usually contains zero. The only exception is when the data of the 264 * physical eraseblock was moved to another physical eraseblock for 265 * wear-leveling reasons. In this case, UBI calculates CRC checksum of the 266 * contents and uses both @data_crc and @data_size fields. In this case, the 267 * @data_size field contains data size. 268 * 269 * The @used_ebs field is used only for static volumes and indicates how many 270 * eraseblocks the data of the volume takes. For dynamic volumes this field is 271 * not used and always contains zero. 272 * 273 * The @data_pad is calculated when volumes are created using the alignment 274 * parameter. So, effectively, the @data_pad field reduces the size of logical 275 * eraseblocks of this volume. This is very handy when one uses block-oriented 276 * software (say, cramfs) on top of the UBI volume. 277 */ 278 struct ubi_vid_hdr { 279 __be32 magic; 280 __u8 version; 281 __u8 vol_type; 282 __u8 copy_flag; 283 __u8 compat; 284 __be32 vol_id; 285 __be32 lnum; 286 __u8 padding1[4]; 287 __be32 data_size; 288 __be32 used_ebs; 289 __be32 data_pad; 290 __be32 data_crc; 291 __u8 padding2[4]; 292 __be64 sqnum; 293 __u8 padding3[12]; 294 __be32 hdr_crc; 295 } __packed; 296 297 /* Internal UBI volumes count */ 298 #define UBI_INT_VOL_COUNT 1 299 300 /* 301 * Starting ID of internal volumes: 0x7fffefff. 302 * There is reserved room for 4096 internal volumes. 303 */ 304 #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096) 305 306 /* The layout volume contains the volume table */ 307 308 #define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START 309 #define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC 310 #define UBI_LAYOUT_VOLUME_ALIGN 1 311 #define UBI_LAYOUT_VOLUME_EBS 2 312 #define UBI_LAYOUT_VOLUME_NAME "layout volume" 313 #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT 314 315 /* The maximum number of volumes per one UBI device */ 316 #define UBI_MAX_VOLUMES 128 317 318 /* The maximum volume name length */ 319 #define UBI_VOL_NAME_MAX 127 320 321 /* Size of the volume table record */ 322 #define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record) 323 324 /* Size of the volume table record without the ending CRC */ 325 #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32)) 326 327 /** 328 * struct ubi_vtbl_record - a record in the volume table. 329 * @reserved_pebs: how many physical eraseblocks are reserved for this volume 330 * @alignment: volume alignment 331 * @data_pad: how many bytes are unused at the end of the each physical 332 * eraseblock to satisfy the requested alignment 333 * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) 334 * @upd_marker: if volume update was started but not finished 335 * @name_len: volume name length 336 * @name: the volume name 337 * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG) 338 * @padding: reserved, zeroes 339 * @crc: a CRC32 checksum of the record 340 * 341 * The volume table records are stored in the volume table, which is stored in 342 * the layout volume. The layout volume consists of 2 logical eraseblock, each 343 * of which contains a copy of the volume table (i.e., the volume table is 344 * duplicated). The volume table is an array of &struct ubi_vtbl_record 345 * objects indexed by the volume ID. 346 * 347 * If the size of the logical eraseblock is large enough to fit 348 * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES 349 * records. Otherwise, it contains as many records as it can fit (i.e., size of 350 * logical eraseblock divided by sizeof(struct ubi_vtbl_record)). 351 * 352 * The @upd_marker flag is used to implement volume update. It is set to %1 353 * before update and set to %0 after the update. So if the update operation was 354 * interrupted, UBI knows that the volume is corrupted. 355 * 356 * The @alignment field is specified when the volume is created and cannot be 357 * later changed. It may be useful, for example, when a block-oriented file 358 * system works on top of UBI. The @data_pad field is calculated using the 359 * logical eraseblock size and @alignment. The alignment must be multiple to the 360 * minimal flash I/O unit. If @alignment is 1, all the available space of 361 * the physical eraseblocks is used. 362 * 363 * Empty records contain all zeroes and the CRC checksum of those zeroes. 364 */ 365 struct ubi_vtbl_record { 366 __be32 reserved_pebs; 367 __be32 alignment; 368 __be32 data_pad; 369 __u8 vol_type; 370 __u8 upd_marker; 371 __be16 name_len; 372 __u8 name[UBI_VOL_NAME_MAX+1]; 373 __u8 flags; 374 __u8 padding[23]; 375 __be32 crc; 376 } __packed; 377 378 /* UBI fastmap on-flash data structures */ 379 380 #define UBI_FM_SB_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 1) 381 #define UBI_FM_DATA_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 2) 382 383 /* fastmap on-flash data structure format version */ 384 #define UBI_FM_FMT_VERSION 1 385 386 #define UBI_FM_SB_MAGIC 0x7B11D69F 387 #define UBI_FM_HDR_MAGIC 0xD4B82EF7 388 #define UBI_FM_VHDR_MAGIC 0xFA370ED1 389 #define UBI_FM_POOL_MAGIC 0x67AF4D08 390 #define UBI_FM_EBA_MAGIC 0xf0c040a8 391 392 /* A fastmap supber block can be located between PEB 0 and 393 * UBI_FM_MAX_START */ 394 #define UBI_FM_MAX_START 64 395 396 /* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */ 397 #define UBI_FM_MAX_BLOCKS 32 398 399 /* 5% of the total number of PEBs have to be scanned while attaching 400 * from a fastmap. 401 * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and 402 * UBI_FM_MAX_POOL_SIZE */ 403 #define UBI_FM_MIN_POOL_SIZE 8 404 #define UBI_FM_MAX_POOL_SIZE 256 405 406 #define UBI_FM_WL_POOL_SIZE 25 407 408 /** 409 * struct ubi_fm_sb - UBI fastmap super block 410 * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC) 411 * @version: format version of this fastmap 412 * @data_crc: CRC over the fastmap data 413 * @used_blocks: number of PEBs used by this fastmap 414 * @block_loc: an array containing the location of all PEBs of the fastmap 415 * @block_ec: the erase counter of each used PEB 416 * @sqnum: highest sequence number value at the time while taking the fastmap 417 * 418 */ 419 struct ubi_fm_sb { 420 __be32 magic; 421 __u8 version; 422 __u8 padding1[3]; 423 __be32 data_crc; 424 __be32 used_blocks; 425 __be32 block_loc[UBI_FM_MAX_BLOCKS]; 426 __be32 block_ec[UBI_FM_MAX_BLOCKS]; 427 __be64 sqnum; 428 __u8 padding2[32]; 429 } __packed; 430 431 /** 432 * struct ubi_fm_hdr - header of the fastmap data set 433 * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC) 434 * @free_peb_count: number of free PEBs known by this fastmap 435 * @used_peb_count: number of used PEBs known by this fastmap 436 * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap 437 * @bad_peb_count: number of bad PEBs known by this fastmap 438 * @erase_peb_count: number of bad PEBs which have to be erased 439 * @vol_count: number of UBI volumes known by this fastmap 440 */ 441 struct ubi_fm_hdr { 442 __be32 magic; 443 __be32 free_peb_count; 444 __be32 used_peb_count; 445 __be32 scrub_peb_count; 446 __be32 bad_peb_count; 447 __be32 erase_peb_count; 448 __be32 vol_count; 449 __u8 padding[4]; 450 } __packed; 451 452 /* struct ubi_fm_hdr is followed by two struct ubi_fm_scan_pool */ 453 454 /** 455 * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching 456 * @magic: pool magic numer (%UBI_FM_POOL_MAGIC) 457 * @size: current pool size 458 * @max_size: maximal pool size 459 * @pebs: an array containing the location of all PEBs in this pool 460 */ 461 struct ubi_fm_scan_pool { 462 __be32 magic; 463 __be16 size; 464 __be16 max_size; 465 __be32 pebs[UBI_FM_MAX_POOL_SIZE]; 466 __be32 padding[4]; 467 } __packed; 468 469 /* ubi_fm_scan_pool is followed by nfree+nused struct ubi_fm_ec records */ 470 471 /** 472 * struct ubi_fm_ec - stores the erase counter of a PEB 473 * @pnum: PEB number 474 * @ec: ec of this PEB 475 */ 476 struct ubi_fm_ec { 477 __be32 pnum; 478 __be32 ec; 479 } __packed; 480 481 /** 482 * struct ubi_fm_volhdr - Fastmap volume header 483 * it identifies the start of an eba table 484 * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC) 485 * @vol_id: volume id of the fastmapped volume 486 * @vol_type: type of the fastmapped volume 487 * @data_pad: data_pad value of the fastmapped volume 488 * @used_ebs: number of used LEBs within this volume 489 * @last_eb_bytes: number of bytes used in the last LEB 490 */ 491 struct ubi_fm_volhdr { 492 __be32 magic; 493 __be32 vol_id; 494 __u8 vol_type; 495 __u8 padding1[3]; 496 __be32 data_pad; 497 __be32 used_ebs; 498 __be32 last_eb_bytes; 499 __u8 padding2[8]; 500 } __packed; 501 502 /* struct ubi_fm_volhdr is followed by one struct ubi_fm_eba records */ 503 504 /** 505 * struct ubi_fm_eba - denotes an association beween a PEB and LEB 506 * @magic: EBA table magic number 507 * @reserved_pebs: number of table entries 508 * @pnum: PEB number of LEB (LEB is the index) 509 */ 510 struct ubi_fm_eba { 511 __be32 magic; 512 __be32 reserved_pebs; 513 __be32 pnum[0]; 514 } __packed; 515 #endif /* !__UBI_MEDIA_H__ */ 516