/* * Copyright (c) International Business Machines Corp., 2006 * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See * the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Authors: Artem B. Bityutskiy * 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_HEADER_H__ #define __UBI_HEADER_H__ #include /* The version of this UBI implementation */ #define UBI_VERSION 1 /* The highest erase counter value supported by this implementation of UBI */ #define UBI_MAX_ERASECOUNTER 0x7FFFFFFF /* The initial CRC32 value used when calculating CRC checksums */ #define UBI_CRC32_INIT 0xFFFFFFFFU /* * Magic numbers of the UBI headers. * * @UBI_EC_HDR_MAGIC: erase counter header magic number (ASCII "UBI#") * @UBI_VID_HDR_MAGIC: volume identifier header magic number (ASCII "UBI!") */ enum { UBI_EC_HDR_MAGIC = 0x55424923, UBI_VID_HDR_MAGIC = 0x55424921 }; /* * Molume type constants used in volume identifier headers. * * @UBI_VID_DYNAMIC: dynamic volume * @UBI_VID_STATIC: static volume */ enum { UBI_VID_DYNAMIC = 1, UBI_VID_STATIC = 2 }; /* * 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 unit 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 }; /* * ubi16_t/ubi32_t/ubi64_t - 16, 32, and 64-bit integers used in UBI on-flash * data structures. */ typedef struct { uint16_t int16; } __attribute__ ((packed)) ubi16_t; typedef struct { uint32_t int32; } __attribute__ ((packed)) ubi32_t; typedef struct { uint64_t int64; } __attribute__ ((packed)) ubi64_t; /* * In this implementation UBI uses the big-endian format for on-flash integers. * The below are the corresponding endianess conversion macros. */ #define cpu_to_ubi16(x) ((ubi16_t){cpu_to_be16(x)}) #define ubi16_to_cpu(x) ((uint16_t)be16_to_cpu((x).int16)) #define cpu_to_ubi32(x) ((ubi32_t){cpu_to_be32(x)}) #define ubi32_to_cpu(x) ((uint32_t)be32_to_cpu((x).int32)) #define cpu_to_ubi64(x) ((ubi64_t){cpu_to_be64(x)}) #define ubi64_to_cpu(x) ((uint64_t)be64_to_cpu((x).int64)) /* * 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(ubi32_t)) #define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(ubi32_t)) /* * How much private data may internal volumes store in the VID header. */ #define UBI_VID_HDR_IVOL_DATA_SIZE 12 /** * struct ubi_ec_hdr - UBI erase counter header. * * @magic: the erase counter header magic number (%UBI_EC_HDR_MAGIC) * @version: the version of UBI implementation which is supposed to accept this * UBI image (%UBI_VERSION) * @padding1: reserved for future, zeroes * @ec: the erase counter * @vid_hdr_offset: where the VID header begins * @data_offset: where the user data begins * @padding2: reserved for future, zeroes * @hdr_crc: the 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 then the current UBI * version, the image is rejecter. 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 the * volume identifier header and user data, relative to the beginning of the * eraseblock. These values have to be the same for all eraseblocks. */ struct ubi_ec_hdr { ubi32_t magic; uint8_t version; uint8_t padding1[3]; ubi64_t ec; /* Warning: the current limit is 31-bit anyway! */ ubi32_t vid_hdr_offset; ubi32_t data_offset; uint8_t padding2[36]; ubi32_t hdr_crc; } __attribute__ ((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: a flag indicating if this physical eraseblock was created by * means of copying an original physical eraseblock to ensure wear-leveling. * @compat: compatibility of this volume (%UBI_COMPAT_DELETE, * %UBI_COMPAT_IGNORE, %UBI_COMPAT_PRESERVE, or %UBI_COMPAT_REJECT) * @vol_id: volume ID * @lnum: logical eraseblock number * @leb_ver: eraseblock copy number * @data_size: how many bytes of data this eraseblock contains. * @used_ebs: total number of used logical eraseblocks in this volume * @data_pad: how many bytes at the end of this eraseblock are not used * @data_crc: CRC checksum of data containing in this eraseblock * @padding1: reserved for future, zeroes * @ivol_data: private data of internal volumes * @hdr_crc: volume identifier header CRC checksum * * The @leb_ver and the @copy_flag fields are used to distinguish between older * and newer copies of logical eraseblocks, as well as to guarantee robustness * to unclean reboots. As UBI erases logical eraseblocks asynchronously, it has * to distinguish between older and newer copies of eraseblocks. This is done * using the @version field. On the other hand, when UBI moves an eraseblock, * its version is also increased and the @copy_flag is set to 1. Additionally, * when moving eraseblocks, UBI calculates data CRC and stores it in the * @data_crc field, even for dynamic volumes. * * Thus, if there are 2 eraseblocks of the same volume and logical number, UBI * uses the following algorithm to pick one of them. It first picks the one * with larger version (say, A). If @copy_flag is not set, then A is picked. If * @copy_flag is set, UBI checks the CRC of the eraseblock (@data_crc). This is * needed to ensure that copying was finished. If the CRC is all right, A is * picked. If not, the older eraseblock is picked. * * Note, the @leb_ver field may overflow. Thus, if you have 2 versions A and B, * then A > B if abs(A-B) < 0x7FFFFFFF, and A < B otherwise. * * There are 2 sorts of volumes in UBI: user volumes and internal volumes. * Internal volumes are not seen from outside and are used for different * internal UBI purposes. In this implementation there are only two internal * volumes: the layout volume and the update volume. Internal volumes are the * main mechanism of UBI extensions. For example, in future one may introduce a * journal internal volume. * * The @compat field is only used for internal volumes and contains the degree * of their compatibility. This field 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 an * journal internal volume in future, he would probably use %UBI_COMPAT_DELETE * compatibility. And in this case, older UBI binaries, which know nothing * about the journal volume, would just delete this and work perfectly fine. * This is somewhat 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 * logical eraseblock was moved by the wear-leveling unit, then the * wear-leveling unit calculates the eraseblocks' CRC and stores it at * @data_crc. * * The @data_size field is always used for static volumes because we want to * know about how many bytes of data are stored in this eraseblock. For * dynamic eraseblocks, this field usually contains zero. The only exception is * when the logical eraseblock is moved to another physical eraseblock due to * 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 the size of logical eraseblock of this volume * (which may vary owing to @alignment). * * 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. * * The @ivol_data contains private data of internal volumes. This might be very * handy to store data in the VID header, not in the eraseblock's contents. For * example it may make life of simple boot-loaders easier. The @ivol_data field * contains zeroes for user volumes. */ struct ubi_vid_hdr { ubi32_t magic; uint8_t version; uint8_t vol_type; uint8_t copy_flag; uint8_t compat; ubi32_t vol_id; ubi32_t lnum; ubi32_t leb_ver; ubi32_t data_size; ubi32_t used_ebs; ubi32_t data_pad; ubi32_t data_crc; uint8_t padding1[12]; uint8_t ivol_data[UBI_VID_HDR_IVOL_DATA_SIZE]; ubi32_t hdr_crc; } __attribute__ ((packed)); /** * struct ubi_vid_hdr_upd_vol - private data of the update internal volume * stored in volume identifier headers. * * @vol_id: volume ID of the volume under update * @padding: zeroes */ struct ubi_vid_hdr_upd_vol { ubi32_t vol_id; uint8_t padding[UBI_VID_HDR_IVOL_DATA_SIZE-4]; } __attribute__ ((packed)); /* * Count of internal UBI volumes. */ #define UBI_INT_VOL_COUNT 2 /* * Internal volume IDs start from this digit. There is a reserved room for 4096 * internal volumes. */ #define UBI_INTERNAL_VOL_START (0x7FFFFFFF - 4096) /* * enum ubi_internal_volume_numbers - volume IDs of internal UBI volumes. * * %UBI_LAYOUT_VOL_ID: volume ID of the layout volume * %UBI_UPDATE_VOL_ID: volume ID of the update volume */ enum { UBI_LAYOUT_VOL_ID = UBI_INTERNAL_VOL_START, UBI_UPDATE_VOL_ID = UBI_INTERNAL_VOL_START + 1 }; /* * Number of logical eraseblocks reserved for internal volumes. */ #define UBI_LAYOUT_VOLUME_EBS 2 #define UBI_UPDATE_VOLUME_EBS 1 /* * Names of internal volumes */ #define UBI_LAYOUT_VOLUME_NAME "The layout volume" #define UBI_UPDATE_VOLUME_NAME "The update volume" /* * Compatibility flags of internal volumes. */ #define UBI_LAYOUT_VOLUME_COMPAT UBI_COMPAT_REJECT #define UBI_UPDATE_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 volume table records. */ #define UBI_VTBL_RECORD_SIZE sizeof(struct ubi_vol_tbl_record) /* * Size of volume table records without the ending CRC. */ #define UBI_VTBL_RECORD_SIZE_CRC (UBI_VTBL_RECORD_SIZE - sizeof(ubi32_t)) /** * struct ubi_vol_tbl_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 not used at the end of the eraseblocks to * satisfy the requested alignment * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) * @padding1: reserved, zeroes * @name_len: the volume name length * @name: the volume name * @padding2: reserved, zeroes * @crc: a CRC32 checksum of the record * * The layout volume consists of 2 logical eraseblock, each of which contains * the volume table (i.e., the volume table is duplicated). The volume table is * an array of &struct ubi_vol_tbl_record objects indexed by the volume ID. * * If the size of the logical eraseblock is large enough to fit * %UBI_MAX_VOLUMES, the volume table contains %UBI_MAX_VOLUMES records. * Otherwise, it contains as much records as can be fit (i.e., size of logical * eraseblock divided by sizeof(struct ubi_vol_tbl_record)). * * 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 * eraseblocks is used. * * Empty records contain all zeroes and the CRC checksum of those zeroes. */ struct ubi_vol_tbl_record { ubi32_t reserved_pebs; ubi32_t alignment; ubi32_t data_pad; uint8_t vol_type; uint8_t padding1; ubi16_t name_len; uint8_t name[UBI_VOL_NAME_MAX+1]; uint8_t padding2[24]; ubi32_t crc; } __attribute__ ((packed)); #endif /* !__UBI_HEADER_H__ */