/* SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause) */ /* * Copyright (C) International Business Machines Corp., 2006 * Authors: Artem Bityutskiy (Битюцкий Артём) * Thomas Gleixner * Frank Haverkamp * Oliver Lohmann * Andreas Arnez * * This file defines the layout of UBI headers and all the other UBI on-flash * data structures. */ #ifndef __UBI_MEDIA_H__ #define __UBI_MEDIA_H__ #include <asm/byteorder.h> /* The version of UBI images supported by this implementation */ #define UBI_VERSION 1 /* The highest erase counter value supported by this implementation */ #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF /* The initial CRC32 value used when calculating CRC checksums */ #define UBI_CRC32_INIT 0xFFFFFFFFU /* Erase counter header magic number (ASCII "UBI#") */ #define UBI_EC_HDR_MAGIC 0x55424923 /* Volume identifier header magic number (ASCII "UBI!") */ #define UBI_VID_HDR_MAGIC 0x55424921 /* * Volume type constants used in the volume identifier header. * * @UBI_VID_DYNAMIC: dynamic volume * @UBI_VID_STATIC: static volume */ enum { UBI_VID_DYNAMIC = 1, UBI_VID_STATIC = 2 }; /* * Volume flags used in the volume table record. * * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at * open time. Should only be set on volumes that * are used by upper layers doing this kind of * check. Main use-case for this flag is * boot-time reduction * * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume * table. UBI automatically re-sizes the volume which has this flag and makes * the volume to be of largest possible size. This means that if after the * initialization UBI finds out that there are available physical eraseblocks * present on the device, it automatically appends all of them to the volume * (the physical eraseblocks reserved for bad eraseblocks handling and other * reserved physical eraseblocks are not taken). So, if there is a volume with * the %UBI_VTBL_AUTORESIZE_FLG flag set, the amount of available logical * eraseblocks will be zero after UBI is loaded, because all of them will be * reserved for this volume. Note, the %UBI_VTBL_AUTORESIZE_FLG bit is cleared * after the volume had been initialized. * * The auto-resize feature is useful for device production purposes. For * example, different NAND flash chips may have different amount of initial bad * eraseblocks, depending of particular chip instance. Manufacturers of NAND * chips usually guarantee that the amount of initial bad eraseblocks does not * exceed certain percent, e.g. 2%. When one creates an UBI image which will be * flashed to the end devices in production, he does not know the exact amount * of good physical eraseblocks the NAND chip on the device will have, but this * number is required to calculate the volume sized and put them to the volume * table of the UBI image. In this case, one of the volumes (e.g., the one * which will store the root file system) is marked as "auto-resizable", and * UBI will adjust its size on the first boot if needed. * * Note, first UBI reserves some amount of physical eraseblocks for bad * eraseblock handling, and then re-sizes the volume, not vice-versa. This * means that the pool of reserved physical eraseblocks will always be present. */ enum { UBI_VTBL_AUTORESIZE_FLG = 0x01, UBI_VTBL_SKIP_CRC_CHECK_FLG = 0x02, }; /* * Compatibility constants used by internal volumes. * * @UBI_COMPAT_DELETE: delete this internal volume before anything is written * to the flash * @UBI_COMPAT_RO: attach this device in read-only mode * @UBI_COMPAT_PRESERVE: preserve this internal volume - do not touch its * physical eraseblocks, don't allow the wear-leveling * sub-system to move them * @UBI_COMPAT_REJECT: reject this UBI image */ enum { UBI_COMPAT_DELETE = 1, UBI_COMPAT_RO = 2, UBI_COMPAT_PRESERVE = 4, UBI_COMPAT_REJECT = 5 }; /* Sizes of UBI headers */ #define UBI_EC_HDR_SIZE sizeof(struct ubi_ec_hdr) #define UBI_VID_HDR_SIZE sizeof(struct ubi_vid_hdr) /* Sizes of UBI headers without the ending CRC */ #define UBI_EC_HDR_SIZE_CRC (UBI_EC_HDR_SIZE - sizeof(__be32)) #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(__be32)) /** * struct ubi_ec_hdr - UBI erase counter header. * @magic: erase counter header magic number (%UBI_EC_HDR_MAGIC) * @version: version of UBI implementation which is supposed to accept this * UBI image * @padding1: reserved for future, zeroes * @ec: the erase counter * @vid_hdr_offset: where the VID header starts * @data_offset: where the user data start * @image_seq: image sequence number * @padding2: reserved for future, zeroes * @hdr_crc: erase counter header CRC checksum * * The erase counter header takes 64 bytes and has a plenty of unused space for * future usage. The unused fields are zeroed. The @version field is used to * indicate the version of UBI implementation which is supposed to be able to * work with this UBI image. If @version is greater than the current UBI * version, the image is rejected. This may be useful in future if something * is changed radically. This field is duplicated in the volume identifier * header. * * The @vid_hdr_offset and @data_offset fields contain the offset of the * volume identifier header and user data, relative to the beginning of the * physical eraseblock. These values have to be the same for all physical * eraseblocks. * * The @image_seq field is used to validate a UBI image that has been prepared * for a UBI device. The @image_seq value can be any value, but it must be the * same on all eraseblocks. UBI will ensure that all new erase counter headers * also contain this value, and will check the value when attaching the flash. * One way to make use of @image_seq is to increase its value by one every time * an image is flashed over an existing image, then, if the flashing does not * complete, UBI will detect the error when attaching the media. */ struct ubi_ec_hdr { __be32 magic; __u8 version; __u8 padding1[3]; __be64 ec; /* Warning: the current limit is 31-bit anyway! */ __be32 vid_hdr_offset; __be32 data_offset; __be32 image_seq; __u8 padding2[32]; __be32 hdr_crc; } __packed; /** * struct ubi_vid_hdr - on-flash UBI volume identifier header. * @magic: volume identifier header magic number (%UBI_VID_HDR_MAGIC) * @version: UBI implementation version which is supposed to accept this UBI * image (%UBI_VERSION) * @vol_type: volume type (%UBI_VID_DYNAMIC or %UBI_VID_STATIC) * @copy_flag: if this logical eraseblock was copied from another physical * eraseblock (for wear-leveling reasons) * @compat: compatibility of this volume (%0, %UBI_COMPAT_DELETE, * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT) * @vol_id: ID of this volume * @lnum: logical eraseblock number * @padding1: reserved for future, zeroes * @data_size: how many bytes of data this logical eraseblock contains * @used_ebs: total number of used logical eraseblocks in this volume * @data_pad: how many bytes at the end of this physical eraseblock are not * used * @data_crc: CRC checksum of the data stored in this logical eraseblock * @padding2: reserved for future, zeroes * @sqnum: sequence number * @padding3: reserved for future, zeroes * @hdr_crc: volume identifier header CRC checksum * * The @sqnum is the value of the global sequence counter at the time when this * VID header was created. The global sequence counter is incremented each time * UBI writes a new VID header to the flash, i.e. when it maps a logical * eraseblock to a new physical eraseblock. The global sequence counter is an * unsigned 64-bit integer and we assume it never overflows. The @sqnum * (sequence number) is used to distinguish between older and newer versions of * logical eraseblocks. * * There are 2 situations when there may be more than one physical eraseblock * corresponding to the same logical eraseblock, i.e., having the same @vol_id * and @lnum values in the volume identifier header. Suppose we have a logical * eraseblock L and it is mapped to the physical eraseblock P. * * 1. Because UBI may erase physical eraseblocks asynchronously, the following * situation is possible: L is asynchronously erased, so P is scheduled for * erasure, then L is written to,i.e. mapped to another physical eraseblock P1, * so P1 is written to, then an unclean reboot happens. Result - there are 2 * physical eraseblocks P and P1 corresponding to the same logical eraseblock * L. But P1 has greater sequence number, so UBI picks P1 when it attaches the * flash. * * 2. From time to time UBI moves logical eraseblocks to other physical * eraseblocks for wear-leveling reasons. If, for example, UBI moves L from P * to P1, and an unclean reboot happens before P is physically erased, there * are two physical eraseblocks P and P1 corresponding to L and UBI has to * select one of them when the flash is attached. The @sqnum field says which * PEB is the original (obviously P will have lower @sqnum) and the copy. But * it is not enough to select the physical eraseblock with the higher sequence * number, because the unclean reboot could have happen in the middle of the * copying process, so the data in P is corrupted. It is also not enough to * just select the physical eraseblock with lower sequence number, because the * data there may be old (consider a case if more data was added to P1 after * the copying). Moreover, the unclean reboot may happen when the erasure of P * was just started, so it result in unstable P, which is "mostly" OK, but * still has unstable bits. * * UBI uses the @copy_flag field to indicate that this logical eraseblock is a * copy. UBI also calculates data CRC when the data is moved and stores it at * the @data_crc field of the copy (P1). So when UBI needs to pick one physical * eraseblock of two (P or P1), the @copy_flag of the newer one (P1) is * examined. If it is cleared, the situation is simple and the newer one is * picked. If it is set, the data CRC of the copy (P1) is examined. If the CRC * checksum is correct, this physical eraseblock is selected (P1). Otherwise * the older one (P) is selected. * * There are 2 sorts of volumes in UBI: user volumes and internal volumes. * Internal volumes are not seen from outside and are used for various internal * UBI purposes. In this implementation there is only one internal volume - the * layout volume. Internal volumes are the main mechanism of UBI extensions. * For example, in future one may introduce a journal internal volume. Internal * volumes have their own reserved range of IDs. * * The @compat field is only used for internal volumes and contains the "degree * of their compatibility". It is always zero for user volumes. This field * provides a mechanism to introduce UBI extensions and to be still compatible * with older UBI binaries. For example, if someone introduced a journal in * future, he would probably use %UBI_COMPAT_DELETE compatibility for the * journal volume. And in this case, older UBI binaries, which know nothing * about the journal volume, would just delete this volume and work perfectly * fine. This is similar to what Ext2fs does when it is fed by an Ext3fs image * - it just ignores the Ext3fs journal. * * The @data_crc field contains the CRC checksum of the contents of the logical * eraseblock if this is a static volume. In case of dynamic volumes, it does * not contain the CRC checksum as a rule. The only exception is when the * data of the physical eraseblock was moved by the wear-leveling sub-system, * then the wear-leveling sub-system calculates the data CRC and stores it in * the @data_crc field. And of course, the @copy_flag is %in this case. * * The @data_size field is used only for static volumes because UBI has to know * how many bytes of data are stored in this eraseblock. For dynamic volumes, * this field usually contains zero. The only exception is when the data of the * physical eraseblock was moved to another physical eraseblock for * wear-leveling reasons. In this case, UBI calculates CRC checksum of the * contents and uses both @data_crc and @data_size fields. In this case, the * @data_size field contains data size. * * The @used_ebs field is used only for static volumes and indicates how many * eraseblocks the data of the volume takes. For dynamic volumes this field is * not used and always contains zero. * * The @data_pad is calculated when volumes are created using the alignment * parameter. So, effectively, the @data_pad field reduces the size of logical * eraseblocks of this volume. This is very handy when one uses block-oriented * software (say, cramfs) on top of the UBI volume. */ struct ubi_vid_hdr { __be32 magic; __u8 version; __u8 vol_type; __u8 copy_flag; __u8 compat; __be32 vol_id; __be32 lnum; __u8 padding1[4]; __be32 data_size; __be32 used_ebs; __be32 data_pad; __be32 data_crc; __u8 padding2[4]; __be64 sqnum; __u8 padding3[12]; __be32 hdr_crc; } __packed; /* Internal UBI volumes count */ #define UBI_INT_VOL_COUNT 1 /* * Starting ID of internal volumes: 0x7fffefff. * There is reserved room for 4096 internal volumes. */ #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096) /* The layout volume contains the volume table */ #define UBI_LAYOUT_VOLUME_ID UBI_INTERNAL_VOL_START #define UBI_LAYOUT_VOLUME_TYPE UBI_VID_DYNAMIC #define UBI_LAYOUT_VOLUME_ALIGN 1 #define UBI_LAYOUT_VOLUME_EBS 2 #define UBI_LAYOUT_VOLUME_NAME "layout volume" #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT /* The maximum number of volumes per one UBI device */ #define UBI_MAX_VOLUMES 128 /* The maximum volume name length */ #define UBI_VOL_NAME_MAX 127 /* Size of the volume table record */ #define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vtbl_record) /* Size of the volume table record without the ending CRC */ #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(__be32)) /** * struct ubi_vtbl_record - a record in the volume table. * @reserved_pebs: how many physical eraseblocks are reserved for this volume * @alignment: volume alignment * @data_pad: how many bytes are unused at the end of the each physical * eraseblock to satisfy the requested alignment * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) * @upd_marker: if volume update was started but not finished * @name_len: volume name length * @name: the volume name * @flags: volume flags (%UBI_VTBL_AUTORESIZE_FLG) * @padding: reserved, zeroes * @crc: a CRC32 checksum of the record * * The volume table records are stored in the volume table, which is stored in * the layout volume. The layout volume consists of 2 logical eraseblock, each * of which contains a copy of the volume table (i.e., the volume table is * duplicated). The volume table is an array of &struct ubi_vtbl_record * objects indexed by the volume ID. * * If the size of the logical eraseblock is large enough to fit * %UBI_MAX_VOLUMES records, the volume table contains %UBI_MAX_VOLUMES * records. Otherwise, it contains as many records as it can fit (i.e., size of * logical eraseblock divided by sizeof(struct ubi_vtbl_record)). * * The @upd_marker flag is used to implement volume update. It is set to %1 * before update and set to %0 after the update. So if the update operation was * interrupted, UBI knows that the volume is corrupted. * * The @alignment field is specified when the volume is created and cannot be * later changed. It may be useful, for example, when a block-oriented file * system works on top of UBI. The @data_pad field is calculated using the * logical eraseblock size and @alignment. The alignment must be multiple to the * minimal flash I/O unit. If @alignment is 1, all the available space of * the physical eraseblocks is used. * * Empty records contain all zeroes and the CRC checksum of those zeroes. */ struct ubi_vtbl_record { __be32 reserved_pebs; __be32 alignment; __be32 data_pad; __u8 vol_type; __u8 upd_marker; __be16 name_len; __u8 name[UBI_VOL_NAME_MAX+1]; __u8 flags; __u8 padding[23]; __be32 crc; } __packed; /* UBI fastmap on-flash data structures */ #define UBI_FM_SB_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 1) #define UBI_FM_DATA_VOLUME_ID (UBI_LAYOUT_VOLUME_ID + 2) /* fastmap on-flash data structure format version */ #define UBI_FM_FMT_VERSION 1 #define UBI_FM_SB_MAGIC 0x7B11D69F #define UBI_FM_HDR_MAGIC 0xD4B82EF7 #define UBI_FM_VHDR_MAGIC 0xFA370ED1 #define UBI_FM_POOL_MAGIC 0x67AF4D08 #define UBI_FM_EBA_MAGIC 0xf0c040a8 /* A fastmap super block can be located between PEB 0 and * UBI_FM_MAX_START */ #define UBI_FM_MAX_START 64 /* A fastmap can use up to UBI_FM_MAX_BLOCKS PEBs */ #define UBI_FM_MAX_BLOCKS 32 /* 5% of the total number of PEBs have to be scanned while attaching * from a fastmap. * But the size of this pool is limited to be between UBI_FM_MIN_POOL_SIZE and * UBI_FM_MAX_POOL_SIZE */ #define UBI_FM_MIN_POOL_SIZE 8 #define UBI_FM_MAX_POOL_SIZE 256 /** * struct ubi_fm_sb - UBI fastmap super block * @magic: fastmap super block magic number (%UBI_FM_SB_MAGIC) * @version: format version of this fastmap * @data_crc: CRC over the fastmap data * @used_blocks: number of PEBs used by this fastmap * @block_loc: an array containing the location of all PEBs of the fastmap * @block_ec: the erase counter of each used PEB * @sqnum: highest sequence number value at the time while taking the fastmap * */ struct ubi_fm_sb { __be32 magic; __u8 version; __u8 padding1[3]; __be32 data_crc; __be32 used_blocks; __be32 block_loc[UBI_FM_MAX_BLOCKS]; __be32 block_ec[UBI_FM_MAX_BLOCKS]; __be64 sqnum; __u8 padding2[32]; } __packed; /** * struct ubi_fm_hdr - header of the fastmap data set * @magic: fastmap header magic number (%UBI_FM_HDR_MAGIC) * @free_peb_count: number of free PEBs known by this fastmap * @used_peb_count: number of used PEBs known by this fastmap * @scrub_peb_count: number of to be scrubbed PEBs known by this fastmap * @bad_peb_count: number of bad PEBs known by this fastmap * @erase_peb_count: number of bad PEBs which have to be erased * @vol_count: number of UBI volumes known by this fastmap */ struct ubi_fm_hdr { __be32 magic; __be32 free_peb_count; __be32 used_peb_count; __be32 scrub_peb_count; __be32 bad_peb_count; __be32 erase_peb_count; __be32 vol_count; __u8 padding[4]; } __packed; /* struct ubi_fm_hdr is followed by two struct ubi_fm_scan_pool */ /** * struct ubi_fm_scan_pool - Fastmap pool PEBs to be scanned while attaching * @magic: pool magic numer (%UBI_FM_POOL_MAGIC) * @size: current pool size * @max_size: maximal pool size * @pebs: an array containing the location of all PEBs in this pool */ struct ubi_fm_scan_pool { __be32 magic; __be16 size; __be16 max_size; __be32 pebs[UBI_FM_MAX_POOL_SIZE]; __be32 padding[4]; } __packed; /* ubi_fm_scan_pool is followed by nfree+nused struct ubi_fm_ec records */ /** * struct ubi_fm_ec - stores the erase counter of a PEB * @pnum: PEB number * @ec: ec of this PEB */ struct ubi_fm_ec { __be32 pnum; __be32 ec; } __packed; /** * struct ubi_fm_volhdr - Fastmap volume header * it identifies the start of an eba table * @magic: Fastmap volume header magic number (%UBI_FM_VHDR_MAGIC) * @vol_id: volume id of the fastmapped volume * @vol_type: type of the fastmapped volume * @data_pad: data_pad value of the fastmapped volume * @used_ebs: number of used LEBs within this volume * @last_eb_bytes: number of bytes used in the last LEB */ struct ubi_fm_volhdr { __be32 magic; __be32 vol_id; __u8 vol_type; __u8 padding1[3]; __be32 data_pad; __be32 used_ebs; __be32 last_eb_bytes; __u8 padding2[8]; } __packed; /* struct ubi_fm_volhdr is followed by one struct ubi_fm_eba records */ /** * struct ubi_fm_eba - denotes an association between a PEB and LEB * @magic: EBA table magic number * @reserved_pebs: number of table entries * @pnum: PEB number of LEB (LEB is the index) */ struct ubi_fm_eba { __be32 magic; __be32 reserved_pebs; __be32 pnum[]; } __packed; #endif /* !__UBI_MEDIA_H__ */