移植ubuntu core到Arm开发板

最初是想把整个ubuntu移植到MX51开发板,因为项目不需要运行桌面系统,所以只移植了一个基本的ubuntu core系统

 1. 下载ubuntu core rootfs,关于ubuntu core参考https://wiki.ubuntu.com/Core

http://cdimage.ubuntu.com/ubuntu-core/releases/12.04/release/ubuntu-core-12.04.3-core-armhf.tar.gz

这个镜像就是一个rootfs,可以作为根文件系统使用。


2. 把镜像烧写到开发板的一个分区上

  • adb shell进入开发板,busybox mkfs.ext2 /dev/block/mmcblk0p1
  • adb shell进入开发板,mount -t ext2 /dev/block/mmcblk0p1 /mnt
  • adb push ubuntu-core-12.04.3-core-armhf.tar.gz /mnt/
  • adb shell进入开发板,cd /mnt; busybox tar ubuntu-core-12.04.3-core-armhf.tar.gz. 在/dev/block/mmcblk0p1这个分区上建立了一个完整的rootfs,文件系统类型为ext2


3. 我的arm开发板是mx51,修改uboot启动参数如下:

set bootargs_android 'setenv bootargs ${bootargs_base} init=/init rdinit=asdf root=b301 rootfs=ext2 di0_primary video=mxcdi0fb:RGB24,CLAA-WVGA'

粗体是我增加的参数,解释下增加的几个参数:

  • rdinit=asdf,rdinit=后的asdf是胡乱写的,这样会设置ramdisk_execute_command为asdf,就导致内核代码
    if (sys_access((const char __user *) ramdisk_execute_command, 0) != 0) {
    sys_access访问失败,调用prepare_namespace 从mmcblk0p1安装根文件系统
  • root=b301,是/dev/block/mmcblk0p1的16进制主设备号b3和从设备号01
  • rootfs=ext2,文件系统类型

4. 启动开发板,会打印出如下信息:

VFS: Mounted root (ext2 filesystem) on device 179:1.

表示已经mount 根文件系统成功。

这一步可能会出现如下错误:

udevd[123]: unable to receive ctrl connection: Function not implemented
udevd[123]: unable to receive ctrl connection: Function not implemented
udevd[123]: unable to receive ctrl connection: Function not implemented
udevd[123]: unable to receive ctrl connection: Function not implemented
udevd[123]: unable to receive ctrl connection: Function not implemented
udevd[123]: unable to receive ctrl connection: Function not implemented
如果你出现了,那么执行第5步


5. 按链接给的patch, 修改内核

https://github.com/genesi/linux-legacy/commit/a84fac75f38de592e530a2f9f982d7aafec6c288


6. 编译内核并烧写到开发板上,重启系统后,不会再打印step4的错误


7. 支持LCD console,修改内核配置文件如下

@@ -1228,8 +1228,14 @@ CONFIG_FB_MXC_SYNC_PANEL=y
 # Console display driver support
 #
 # CONFIG_VGA_CONSOLE is not set
+# CONFIG_VGACON_SOFT_SCROLLBACK is not set
 CONFIG_DUMMY_CONSOLE=y
-# CONFIG_FRAMEBUFFER_CONSOLE is not set
+CONFIG_FRAMEBUFFER_CONSOLE=y
+# CONFIG_FRAMEBUFFER_CONSOLE_DETECT_PRIMARY is not set
+# CONFIG_FRAMEBUFFER_CONSOLE_ROTATION is not set
+# CONFIG_FONTS is not set
+CONFIG_FONT_8x8=y
+CONFIG_FONT_8x16=y

重新编译内核,重启系统后,可在LCD看到ubuntu的登录console


8 支持serial console,我的开发板没有usbhost,不能接usb键盘,所以需要用serial console控制

  • 在/etc/init.d增加文件/etc/init/ttymxc.conf
  • # console - getty
    #
    # This service maintains a getty on console from the point the system is
    # started until it is shut down again.
    
    start on stopped rc RUNLEVEL=[2345] and container CONTAINER=lxc
    
    stop on runlevel [!2345]
    
    respawn
    exec /sbin/getty -L 115200 ttymxc0 vt102
    

  • 修改rootfs的文件/etc/rc.local,如下
  • #!/bin/sh -e
    #
    # rc.local
    #
    # This script is executed at the end of each multiuser runlevel.
    # Make sure that the script will "exit 0" on success or any other
    # value on error.
    #
    # In order to enable or disable this script just change the execution
    # bits.
    #
    # By default this script does nothing.
    start ttymxc0
    exit 0
    

重新启动后,即可在串口得到控制台信息。




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