Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992563AbXBQRAT (ORCPT ); Sat, 17 Feb 2007 12:00:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992695AbXBQRAS (ORCPT ); Sat, 17 Feb 2007 12:00:18 -0500 Received: from smtp.nokia.com ([131.228.20.170]:52880 "EHLO mgw-ext11.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992563AbXBQQ7z (ORCPT ); Sat, 17 Feb 2007 11:59:55 -0500 From: Artem Bityutskiy To: Linux Kernel Mailing List Cc: Christoph Hellwig , Artem Bityutskiy , Frank Haverkamp , Thomas Gleixner , David Woodhouse , Josh Boyer Date: Sat, 17 Feb 2007 18:54:34 +0200 Message-Id: <20070217165434.5845.54262.sendpatchset@localhost.localdomain> In-Reply-To: <20070217165424.5845.4390.sendpatchset@localhost.localdomain> References: <20070217165424.5845.4390.sendpatchset@localhost.localdomain> Subject: [PATCH 02/44 take 2] [UBI] on-flash data structures header X-OriginalArrivalTime: 17 Feb 2007 16:54:01.0931 (UTC) FILETIME=[39B829B0:01C752B4] X-eXpurgate-Category: 1/0 X-eXpurgate-ID: 149371::070217185101-5EAE2BB0-7403EFAC/0-0/0-1 X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13866 Lines: 346 diff -auNrp tmp-from/include/mtd/ubi-header.h tmp-to/include/mtd/ubi-header.h --- tmp-from/include/mtd/ubi-header.h 1970-01-01 02:00:00.000000000 +0200 +++ tmp-to/include/mtd/ubi-header.h 2007-02-17 18:07:26.000000000 +0200 @@ -0,0 +1,337 @@ +/* + * 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 +}; + +/* + * 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: 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 starts + * @data_offset: where the user data starts + * @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 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 + * 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: ID of this volume + * @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 the data stored in this eraseblock + * @padding1: reserved for future, zeroes + * @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 the logical eraseblock, as well as to guarantee + * robustness against unclean reboots. As UBI erases logical eraseblocks + * asynchronously, in background, it has to distinguish between older and newer + * copies of logical eraseblocks. This is done using the @version field. On the + * other hand, when UBI moves data of an eraseblock, its version is also + * increased and the @copy_flag is set to 1. Additionally, when moving data of + * eraseblocks, UBI calculates data CRC and stores it in the @data_crc field, + * even for dynamic volumes. + * + * Thus, if there are 2 physical eraseblocks belonging to the logical + * eraseblock (same volume ID and logical eraseblock 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 data of this physical eraseblock (@data_crc). + * This is needed to ensure that the copying was finished. If the CRC is all + * right, A is picked. If not, the older physical eraseblock is picked. + * + * Note, the @leb_ver field may overflow. Thus, if you have 2 versions X and Y, + * then X > Y if abs(X-Y) < 0x7FFFFFFF, otherwise X < Y. + * + * 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 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 + * 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; + ubi32_t data_size; + ubi32_t used_ebs; + ubi32_t data_pad; + ubi32_t data_crc; + uint8_t padding1[24]; + ubi32_t hdr_crc; +} __attribute__ ((packed)); + +/* Count of internal UBI volumes */ +#define UBI_INT_VOL_COUNT 1 + +/* + * IDs of internal volumes start from this digit. There is a 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, +}; + +#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 eraseblock to + * satisfy the requested alignment + * @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME) + * @upd_marker: the update marker flag + * @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 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. + * + * 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 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__ */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/