diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/mtd/ubi-header.h | 368 | ||||
| -rw-r--r-- | include/mtd/ubi-user.h | 161 |
2 files changed, 529 insertions, 0 deletions
diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h new file mode 100644 index 0000000..c003d98 --- /dev/null +++ b/include/mtd/ubi-header.h @@ -0,0 +1,368 @@ +/* + * 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. May be included by user-space. + */ + +#ifndef __UBI_HEADER_H__ +#define __UBI_HEADER_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 +}; + +/* + * 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 of UBI uses the big-endian format for on-flash + * integers. The below are the corresponding 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)) + +/** + * 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 { + 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: 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 { + 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; /* obsolete, to be removed, don't use */ + ubi32_t data_size; + ubi32_t used_ebs; + ubi32_t data_pad; + ubi32_t data_crc; + uint8_t padding1[4]; + ubi64_t sqnum; + uint8_t padding2[12]; + ubi32_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) + +/* + * IDs of internal UBI volumes. + * + * %UBI_LAYOUT_VOL_ID: layout volume ID + */ +enum { + UBI_LAYOUT_VOL_ID = UBI_INTERNAL_VOL_START, +}; + +/* The layout volume contains the volume table */ + +#define UBI_LAYOUT_VOLUME_EBS 2 +#define UBI_LAYOUT_VOLUME_NAME "The 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_vol_tbl_record) + +/* Size of the volume table record 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 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 + * @padding2: 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_vol_tbl_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_vol_tbl_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_vol_tbl_record { + ubi32_t reserved_pebs; + ubi32_t alignment; + ubi32_t data_pad; + uint8_t vol_type; + uint8_t upd_marker; + 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__ */ diff --git a/include/mtd/ubi-user.h b/include/mtd/ubi-user.h new file mode 100644 index 0000000..bb0aca6 --- /dev/null +++ b/include/mtd/ubi-user.h @@ -0,0 +1,161 @@ +/* + * 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 + * + * Author: Artem B. Bityutskiy + */ + +#ifndef __UBI_USER_H__ +#define __UBI_USER_H__ + +/* + * UBI volume creation + * ~~~~~~~~~~~~~~~~~~~ + * + * UBI volumes are created via the %UBI_IOCMKVOL IOCTL command of UBI character + * device. A &struct ubi_mkvol_req object has to be properly filled and a + * pointer to it has to be passed to the IOCTL. + * + * UBI volume deletion + * ~~~~~~~~~~~~~~~~~~~ + * + * To delete a volume, the %UBI_IOCRMVOL IOCTL command of the UBI character + * device should be used. A pointer to the 32-bit volume ID hast to be passed + * to the IOCTL. + * + * UBI volume re-size + * ~~~~~~~~~~~~~~~~~~ + * + * To re-size a volume, the %UBI_IOCRSVOL IOCTL command of the UBI character + * device should be used. A &struct ubi_rsvol_req object has to be properly + * filled and a pointer to it has to be passed to the IOCTL. + * + * UBI volume update + * ~~~~~~~~~~~~~~~~~ + * + * Volume update should be done via the %UBI_IOCVOLUP IOCTL command of the + * corresponding UBI volume character device. A pointer to a 64-bit update + * size should be passed to the IOCTL. After then, UBI expects user to write + * this number of bytes to the volume character device. The update is finished + * when the claimed number of bytes is passed. So, the volume update sequence + * is something like: + * + * fd = open("/dev/my_volume"); + * ioctl(fd, UBI_IOCVOLUP, &image_size); + * write(fd, buf, image_size); + * close(fd); + */ + +/* + * When a new volume is created, users may either specify the volume number they + * want to create or to let UBI automatically assign a volume number using this + * constant. + */ +#define UBI_VOL_NUM_AUTO (-1) + +/* Maximum volume name length */ +#define UBI_MAX_VOLUME_NAME 127 + +/* IOCTL commands of UBI character devices */ + +#define UBI_IOC_MAGIC 'o' + +/* Create an UBI volume */ +#define UBI_IOCMKVOL _IOW(UBI_IOC_MAGIC, 0, struct ubi_mkvol_req) +/* Remove an UBI volume */ +#define UBI_IOCRMVOL _IOW(UBI_IOC_MAGIC, 1, int32_t) +/* Re-size an UBI volume */ +#define UBI_IOCRSVOL _IOW(UBI_IOC_MAGIC, 2, struct ubi_rsvol_req) + +/* IOCTL commands of UBI volume character devices */ + +#define UBI_VOL_IOC_MAGIC 'O' + +/* Start UBI volume update */ +#define UBI_IOCVOLUP _IOW(UBI_VOL_IOC_MAGIC, 0, int64_t) +/* An eraseblock erasure command, used for debugging, disabled by default */ +#define UBI_IOCEBER _IOW(UBI_VOL_IOC_MAGIC, 1, int32_t) + +/* + * UBI volume type constants. + * + * @UBI_DYNAMIC_VOLUME: dynamic volume + * @UBI_STATIC_VOLUME: static volume + */ +enum { + UBI_DYNAMIC_VOLUME = 3, + UBI_STATIC_VOLUME = 4 +}; + +/** + * struct ubi_mkvol_req - volume description data structure used in + * volume creation requests. + * @vol_id: volume number + * @alignment: volume alignment + * @bytes: volume size in bytes + * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) + * @padding1: reserved for future, not used + * @name_len: volume name length + * @padding2: reserved for future, not used + * @name: volume name + * + * This structure is used by userspace programs when creating new volumes. The + * @used_bytes field is only necessary when creating static volumes. + * + * The @alignment field specifies the required alignment of the volume logical + * eraseblock. This means, that the size of logical eraseblocks will be aligned + * to this number, i.e., + * (UBI device logical eraseblock size) mod (@alignment) = 0. + * + * To put it differently, the logical eraseblock of this volume may be slightly + * shortened in order to make it properly aligned. The alignment has to be + * multiple of the flash minimal input/output unit, or %1 to utilize the entire + * available space of logical eraseblocks. + * + * The @alignment field may be useful, for example, when one wants to maintain + * a block device on top of an UBI volume. In this case, it is desirable to fit + * an integer number of blocks in logical eraseblocks of this UBI volume. With + * alignment it is possible to update this volume using plane UBI volume image + * BLOBs, without caring about how to properly align them. + */ +struct ubi_mkvol_req { + int32_t vol_id; + int32_t alignment; + int64_t bytes; + int8_t vol_type; + int8_t padding1; + int16_t name_len; + int8_t padding2[4]; + char name[UBI_MAX_VOLUME_NAME+1]; +} __attribute__ ((packed)); + +/** + * struct ubi_rsvol_req - a data structure used in volume re-size requests. + * @vol_id: ID of the volume to re-size + * @bytes: new size of the volume in bytes + * + * Re-sizing is possible for both dynamic and static volumes. But while dynamic + * volumes may be re-sized arbitrarily, static volumes cannot be made to be + * smaller then the number of bytes they bear. To arbitrarily shrink a static + * volume, it must be wiped out first (by means of volume update operation with + * zero number of bytes). + */ +struct ubi_rsvol_req { + int64_t bytes; + int32_t vol_id; +} __attribute__ ((packed)); + +#endif /* __UBI_USER_H__ */ |