UBI: make ubi-header.h local
Linux-MTD Mailing List
linux-mtd at lists.infradead.org
Wed Apr 23 05:59:01 EDT 2008
Gitweb: http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=92a74f1c1c9ca4d8009bfdea1c5febb7c0674f15
Commit: 92a74f1c1c9ca4d8009bfdea1c5febb7c0674f15
Parent: a4f0fcdfb2397e81d22446bb364dc190bf16b25a
Author: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
AuthorDate: Sat Feb 16 15:42:52 2008 +0200
Committer: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
CommitDate: Thu Apr 17 11:31:58 2008 +0300
UBI: make ubi-header.h local
The new trend in linux is not to store headers which define
on-media format in the include/ directory, but instead, store
them locally. This is because these headers "do not define any
kernel<->userspace interface".
Do so for UBI as well.
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy at nokia.com>
---
drivers/mtd/ubi/ubi-media.h | 372 +++++++++++++++++++++++++++++++++++++++++++
drivers/mtd/ubi/ubi.h | 3 +-
include/mtd/Kbuild | 1 -
include/mtd/ubi-header.h | 372 -------------------------------------------
4 files changed, 373 insertions(+), 375 deletions(-)
diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
new file mode 100644
index 0000000..c3185d9
--- /dev/null
+++ b/drivers/mtd/ubi/ubi-media.h
@@ -0,0 +1,372 @@
+/*
+ * 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.
+ */
+
+#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_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(__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
+ * @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 {
+ __be32 magic;
+ __u8 version;
+ __u8 padding1[3];
+ __be64 ec; /* Warning: the current limit is 31-bit anyway! */
+ __be32 vid_hdr_offset;
+ __be32 data_offset;
+ __u8 padding2[36];
+ __be32 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 {
+ __be32 magic;
+ __u8 version;
+ __u8 vol_type;
+ __u8 copy_flag;
+ __u8 compat;
+ __be32 vol_id;
+ __be32 lnum;
+ __be32 leb_ver; /* obsolete, to be removed, don't use */
+ __be32 data_size;
+ __be32 used_ebs;
+ __be32 data_pad;
+ __be32 data_crc;
+ __u8 padding1[4];
+ __be64 sqnum;
+ __u8 padding2[12];
+ __be32 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(__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;
+} __attribute__ ((packed));
+
+#endif /* !__UBI_MEDIA_H__ */
diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
index a548c1d..28de80f 100644
--- a/drivers/mtd/ubi/ubi.h
+++ b/drivers/mtd/ubi/ubi.h
@@ -37,10 +37,9 @@
#include <linux/string.h>
#include <linux/vmalloc.h>
#include <linux/mtd/mtd.h>
-
-#include <mtd/ubi-header.h>
#include <linux/mtd/ubi.h>
+#include "ubi-media.h"
#include "scan.h"
#include "debug.h"
diff --git a/include/mtd/Kbuild b/include/mtd/Kbuild
index 4d46b3b..8eb018f 100644
--- a/include/mtd/Kbuild
+++ b/include/mtd/Kbuild
@@ -3,5 +3,4 @@ header-y += jffs2-user.h
header-y += mtd-abi.h
header-y += mtd-user.h
header-y += nftl-user.h
-header-y += ubi-header.h
header-y += ubi-user.h
diff --git a/include/mtd/ubi-header.h b/include/mtd/ubi-header.h
deleted file mode 100644
index 292f916..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 <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_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(__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
- * @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 {
- __be32 magic;
- __u8 version;
- __u8 padding1[3];
- __be64 ec; /* Warning: the current limit is 31-bit anyway! */
- __be32 vid_hdr_offset;
- __be32 data_offset;
- __u8 padding2[36];
- __be32 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 {
- __be32 magic;
- __u8 version;
- __u8 vol_type;
- __u8 copy_flag;
- __u8 compat;
- __be32 vol_id;
- __be32 lnum;
- __be32 leb_ver; /* obsolete, to be removed, don't use */
- __be32 data_size;
- __be32 used_ebs;
- __be32 data_pad;
- __be32 data_crc;
- __u8 padding1[4];
- __be64 sqnum;
- __u8 padding2[12];
- __be32 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(__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;
-} __attribute__ ((packed));
-
-#endif /* !__UBI_HEADER_H__ */
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