嵌入式Linux之我行，主要讲述和总结了本人在学习嵌入式linux中的每个步骤。一为总结经验，二希望能给想入门嵌入式Linux的朋友提供方便。如有错误之处，谢请指正。

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一、移植环境

• 主  机：VMWare--Fedora 9
• 开发板：Mini2440--64MB Nand
• 编译器：arm-linux-gcc-4.3.2
• yaffs补丁：cvs-root.tar.gz 这里下载http://www.aleph1.co.uk/cgi-bin/viewcvs.cgi/
• Busybox：busybox-1.13.0.tar.tar
• yaffs制作工具：mkyaffs2image.tgz（友善提供）

二、移植步骤 1. 准备工作目录和进入工作目录 #mkdir my2440
#cd my2440 2. 给内核打上yaffs补丁，使内核对yaffs的支持 #tar -zxvf cvs-root.tar.gz
#cd cvs/yaffs2/
#./patch-ker.sh c /root/my2440/linux-2.6.30.4/
3. 配置内核，使其对yaffs2文件系统的支持。配置完后重新编译内核，下载到开发板上 File systems --->
    < > Second extended fs support
    < > Ext3 journalling file system support
    < > The Extended 4 (ext4) filesystem
    < > Reiserfs support
    < > JFS filesystem support
    < > XFS filesystem support
    < > OCFS2 file system support
    < > Btrfs filesystem (EXPERIMENTAL) Unstable disk format
    [*] Enable POSIX file locking API
    [*] Dnotify support
    [*] Inotify file change notification support
    [*] Inotify support for userspace
    [ ] Quota support
     Kernel automounter support
     Kernel automounter version 4 support (also supports v3)
     FUSE (Filesystem in Userspace) support
        Caches --->
        CD-ROM/DVD Filesystems --->
            <*> ISO 9660 CDROM file system support
            [ ] Microsoft Joliet CDROM extensions
            [ ] Transparent decompression extension
            < > UDF file system support
        DOS/FAT/NT Filesystems --->
            <*> MSDOS fs support
            <*> VFAT (Windows-95) fs support
            (437) Default codepage for FAT
            (iso8859-1) Default iocharset for FAT
            < > NTFS file system support
        Pseudo filesystems --->
    [*] Miscellaneous filesystems --->
        --- Miscellaneous filesystems
        < > ADFS file system support (EXPERIMENTAL)
        < > Amiga FFS file system support (EXPERIMENTAL)
        < > Apple Macintosh file system support (EXPERIMENTAL)
        < > Apple Extended HFS file system support
        < > BeOS file system (BeFS) support (read only) (EXPERIMENTAL)
        < > BFS file system support (EXPERIMENTAL)
        < > EFS file system support (read only) (EXPERIMENTAL)
        <*> YAFFS2 file system support
        -*- 512 byte / page devices
        [ ] Use older-style on-NAND data format with pageStatus byte
        [ ] Lets Yaffs do its own ECC
        -*- 2048 byte (or larger) / page devices
        [*] Autoselect yaffs2 format
        [ ] Disable lazy loading
        [ ] Turn off wide tnodes
        [ ] Force chunk erase check
        [*] Cache short names in RAM
        <*> Journalling Flash File System v2 (JFFS2) support
        (0) JFFS2 debugging verbosity (0 = quiet, 2 = noisy)
        [*] JFFS2 write-buffering support
        [ ] Verify JFFS2 write-buffer reads
        [*] JFFS2 summary support (EXPERIMENTAL)
        [ ] JFFS2 XATTR support (EXPERIMENTAL)
        [ ] Advanced compression options for JFFS2
        <*> Compressed ROM file system support (cramfs)
         SquashFS 4.0 - Squashed file system support
        [ ] Additional option for memory-constrained systems
        < > FreeVxFS file system support (VERITAS VxFS(TM) compatible)
        < > Minix file system support
        < > SonicBlue Optimized MPEG File System support
        < > OS/2 HPFS file system support
        < > QNX4 file system support (read only)
        <*> ROM file system support
        RomFS backing stores (Block device-backed ROM file system support) --
        < > System V/Xenix/V7/Coherent file system support
        < > UFS file system support (read only)
        < > NILFS2 file system support (EXPERIMENTAL)
    [*] Network File Systems --->
        Partition Types --->
    -*- Native language support --->
    < > Distributed Lock Manager (DLM) ---> 4. 编译busybox生成文件系统所需要的应用程序    1)解压busybox源码，修改Makefile使之编译成ARM平台: #tar -jxvf busybox-1.13.0.tar.tar
#cd busybox-1.13.0
#gedit Makefile 大概164行改成CROSS_COMPILE = arm-linux- ，189行改成ARCH = arm    2)配置busybox选项，下面只列出了要注意的地方，没有列出的默认即可 #make menuconfig Busybox Settings --->
    General Configuration --->
            Buffer allocation policy (Allocate with Malloc) --->
        [*] Show verbose applet usage messages
        [*] Store applet usage messages in compressed form
        [*] Support --install [-s] to install applet links at runtime
        [*] Enable locale support (system needs locale for this to work)
        [*] Support for --long-options
        [*] Use the devpts filesystem for Unix98 PTYs
        [*] Support writing pidfiles
        [*] Runtime SUID/SGID configuration via /etc/busybox.conf
        [*] Suppress warning message if /etc/busybox.conf is not readable
        (/proc/self/exe) Path to BusyBox executable
    Build Options --->
        [*] Build BusyBox as a static binary (no shared libs)
        [*] Build with Large File Support (for accessing files > 2 GB)
    Installation Options --->
        [ ] Don't use /usr
            Applets links (as soft-links) --->
        (./_install) BusyBox installation prefix
    Busybox Library Tuning --->
        (6) Minimum password length
        (2) MD5: Trade Bytes for Speed
        [*] Faster /proc scanning code (+100 bytes)
        [*] Command line editing
        (1024) Maximum length of input
        [*] vi-style line editing commands
        (15) History size
        [*] History saving
        [*] Tab completion
        [*] Fancy shell prompts
        (4) Copy buffer size, in kilobytes
        [*] Use ioctl names rather than hex values in error messages
        [*] Support infiniband HW
Linux Module Utilities --->
    (/lib/modules) Default directory containing modules
    (modules.dep) Default name of modules.dep
    [*] insmod
    [*] rmmod
    [*] lsmod
    [*] modprobe
    --- Options common to multiple modutils
    [ ] Support version 2.2/2.4 Linux kernels
    [*] Support tainted module checking with new kernels
    [*] Support for module.aliases file
    [*] Support for module.symbols fileLinux System Utilities --->
   3)编译和安装busybox，安装完后会在busybox-1.13.0/_install/目录下生成：bin、linuxrc、sbin、usr #make
#make install 5. 开始构建文件系统    1)新建一个目录root-2.6.30.4，把busybox-1.13.0/_install/目录下生成：bin、linuxrc、sbin、usr复制过来，并且在该目录下创建文件系统所需要的其他目录 #mkdir root-2.6.30.4
#cp -rf busybox-1.13.0/_install/* root-2.6.30.4/
#cd root-2.6.30.4/
#mkdir dev etc home lib mnt opt proc tmp var www    2)向各目录中添加文件系统所需要的目录或文件，没有提到的就不用添加。这里要注意各种文件的权限，建议都改为777，命令：#chmod 777 文件名 "dev"目录，创建两个设备文件： #mknod console c 5 1
#mknod null c 1 3 "etc"目录，创建各种配置文件并向里面添加内容，没有列出的就不用添加： boa/boa.conf: boa WEB服务器配置文件，暂时为空。 group: 系统用户组配置文件，内容如下： root:*:0:
daemon:*:1:
bin:*:2:
sys:*:3:
adm:*:4:
tty:*:5:
disk:*:6:
lp:*:7:lp
mail:*:8:
news:*:9:
uucp:*:10:
proxy:*:13:
kmem:*:15:
dialout:*:20:
fax:*:21:
voice:*:22:
cdrom:*:24:
floppy:*:25:
tape:*:26:
sudo:*:27:
audio:*:29:
ppp:x:99:
500:x:500:plg
501:x:501:fa inittab: 系统init进程配置文件，内容如下： # /etc/inittab
::sysinit:/etc/init.d/rcS
console::askfirst:-/bin/sh
::ctrlaltdel:/sbin/reboot
::shutdown:/bin/umount -a -r mime.types: 暂时为空。 passwd: 系统密码文件，内容如下： root::0:0:root:/:/bin/sh
ftp::14:50:FTP User:/var/ftp:
bin:*:1:1:bin:/bin:
daemon:*:2:2:daemon:/sbin:
nobody:*:99:99:Nobody:/:
sky::502:502:Linux User,,,:/home/sky:/bin/sh rc.d/init.d/httpd: 内容如下： #!/bin/sh

base=boa

# See how we were called.
case "$1" in
  start)
        /usr/sbin/$base
        ;;
  stop)
    pid=`/bin/pidof $base`
    if [ -n "$pid" ]; then
        kill -9 $pid
    fi
        ;;
esac

exit 0 sysconfig/HOSTNAME: 主机名称文件，内容如下： MY2440 fstab: 系统挂载文件系统列表，内容如下： # device  mount-point   type     options     dump   fsck order
none      /proc         proc     defaults    0      0
none      /dev/pts      devpts   mode=0622   0      0
tmpfs     /dev/shm      tmpfs    defaults    0      0 init.d/rcS: 系统启动加载项，内容如下： #!/bin/sh

PATH=/sbin:/bin:/usr/sbin:/usr/bin
runlevel=S
prevlevel=N
umask 022
export PATH runlevel prevlevel

#
#    Trap CTRL-C &c only in this shell so we can interrupt subprocesses.
#
/bin/mount -t proc none /proc
/bin/mount -t tmpfs none /tmp
/bin/mount -t tmpfs none /var

/bin/mkdir -p /var/log

/bin/hostname -F /etc/sysconfig/HOSTNAME mdev.conf: mdev设备配置文件，暂时为空。 net.conf: 网络配置文件，暂时为空。 profile: 用户环境配置文件，内容如下： # Ash profile
# vim: syntax=sh

# No core files by default
#ulimit -S -c 0 > /dev/null 2>&1

USER="`id -un`"
LOGNAME=$USER
PS1='[u@h W]# '
PATH=$PATH:/usr/local/bin
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib
HOSTNAME=`/bin/hostname`

export USER LOGNAME PS1 PATH LD_LIBRARY_PATH resolv.conf: DNS配置文件，内容如下： nameserver 61.144.56.100
"home"目录：创建一个sky目录，与etc目录passwd文件中的sky相对应 "lib"目录：这个里面放的都是库文件，直接从交叉编译器的库文件目录中拷贝过来： #cp -f /usr/local/arm/4.3.2/arm-none-linux-gnueabi/libc/armv4t/lib/*so* lib/ -a

6. 使用yaffs制作工具编译构建好的文件系统。先解压mkyaffs2image.tgz（这个工具是友善提供的，可以在他们的网站上下载），会自动解压到开发主机的/usr/sbin/目录下。编译后生成的文件系统镜像root-2.6.30.4.bin也在这个目录下
#tar -zxvf mkyaffs2image.tgz
#mkyaffs2image root-2.6.30.4/ root-2.6.30.4.bin 7. 下载文件系统镜像到开发板上测试，使用情况如下： 三、结束语     现在文件系统成功移植上去了，加上上一篇章的内核移植，至此开发板可以运行起来了。但是各种外设还不能正常使用，后续的篇章将逐步移植各种设备的驱动，使之完善。