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Diffstat (limited to 'include/mtd/ubi-header.h')
| -rw-r--r-- | include/mtd/ubi-header.h | 372 |
1 files changed, 0 insertions, 372 deletions
diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h deleted file mode 100644 index 386fa3c..0000000 --- a/include/mtd/ubi-header.h +++ /dev/null @@ -1,372 +0,0 @@ -/* - * 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 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. May be included by user-space. - */ - -#ifndef __UBI_HEADER_H__ -#define __UBI_HEADER_H__ - -#include <stdint.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_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, -}; - -/* - * 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 -}; - -/* 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(uint32_t)) -#define UBI_VID_HDR_SIZE_CRC (UBI_VID_HDR_SIZE - sizeof(uint32_t)) - -/** - * 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 - * @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 then 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 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. - */ -struct ubi_ec_hdr { - uint32_t magic; - uint8_t version; - uint8_t padding1[3]; - uint64_t ec; /* Warning: the current limit is 31-bit anyway! */ - uint32_t vid_hdr_offset; - uint32_t data_offset; - uint8_t padding2[36]; - uint32_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: 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 - * @leb_ver: version of this logical eraseblock (IMPORTANT: obsolete, to be - * removed, kept only for not breaking older UBI users) - * @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 - * @padding1: reserved for future, zeroes - * @sqnum: sequence number - * @padding2: 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 then 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. - * - * Note, there is an obsolete @leb_ver field which was used instead of @sqnum - * in the past. But it is not used anymore and we keep it in order to be able - * to deal with old UBI images. It will be removed at some point. - * - * 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 unit, then - * the wear-leveling unit 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 { - uint32_t magic; - uint8_t version; - uint8_t vol_type; - uint8_t copy_flag; - uint8_t compat; - uint32_t vol_id; - uint32_t lnum; - uint32_t leb_ver; /* obsolete, to be removed, don't use */ - uint32_t data_size; - uint32_t used_ebs; - uint32_t data_pad; - uint32_t data_crc; - uint8_t padding1[4]; - uint64_t sqnum; - uint8_t padding2[12]; - uint32_t hdr_crc; -} __attribute__ ((packed)); - -/* Internal UBI volumes count */ -#define UBI_INT_VOL_COUNT 1 - -/* - * Starting ID of internal volumes. 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(uint32_t)) - -/** - * 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 { - uint32_t reserved_pebs; - uint32_t alignment; - uint32_t data_pad; - uint8_t vol_type; - uint8_t upd_marker; - uint16_t name_len; - uint8_t name[UBI_VOL_NAME_MAX+1]; - uint8_t flags; - uint8_t padding[23]; - uint32_t crc; -} __attribute__ ((packed)); - -#endif /* !__UBI_HEADER_H__ */ |