How to Remotely Boot PcDuino From a NFS Server

In cases, we would like pcDuino to boot from a network hosted file
system. In this tutorial, we will explain how to make this happen.

We will first set up a NFS server. The following command will be used on a X86 server, and starts with the character ‘#’.
To install NFS server, we type the following command:

#sudo apt-get install nfs-kernel-server

Configure the root directory of the network file system:

#sudo vim /etc/exports

The following is the content:

# /etc/exports: the access control list for filesystems which may be exported
#       to NFS clients.  See exports(5).
#
# Example for NFSv2 and NFSv3:
# /srv/homes       hostname1(rw,sync,no_subtree_check) hostname2(ro,sync,no_subtree_check)
#
# Example for NFSv4:
# /srv/nfs4        gss/krb5i(rw,sync,fsid=0,crossmnt,no_subtree_check)
# /srv/nfs4/homes  gss/krb5i(rw,sync,no_subtree_check)
#
/home/pillar/rootfs *(rw,sync,no_root_squash,no_subtree_check)

In the above, we set the directory ‘/home/pillar/rootfs’ as the root directory of the file system.
To make the setting valid, we need to the following:

#sudo /etc/init.d/portmap restart
#sudo /etc/init.d/nfs-kernel-server restart

We can use the following command to show the shared directory:

#showmount -e

To mount the rootfs, we need to copy the pcDuino rootfs file
“pcduino_ubuntu_20131126.img” or new rootfs image to the nfs server, and mount the image to rootfs:

#sudo mount -t ext3 -o loop pcduino_ubuntu_20131126.img  rootfs/

To check the mounted content,

To see photo:

When we reboot the ubuntu nfs server, it will get IP address by DHCP. As
pcDuino replies on the server to boot, we need to configure a static IP address:

#sudo vim rootfs/etc/network/interfaces

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback
auto eth0
iface eth0 inet static

We need to modify the kernel in two places to support nfs.
1. Uncheck initramfs:

General setup  --->
        [ ] Initial RAM filesystem and RAM disk (initramfs/initrd) support

2. Check NSF support:

File systems  --->
    [*] Network File Systems  --->
        [*]   Root file system on NFS

After finishing the build process, flash the kernel to the board. We don’t need to flash the rootfs.
We provide a copy of finished kernel. The built kernel can be downloaded at here.

We also need to configure u-boot to support network boot. After reboot,
the booting information will be displayed on the debug terminal (which is accessed from the debug serial port using a serial USB debug cable):

to see photo:

When the uboot is starting, we need to press any key, and stop the booting. Then we type the following:

>setenv setargs setenv bootargs  root=/dev/nfs ip=192.168.2.7:196.168.2.1:255.255.255.0:::eth0 nfsroot=192.168.2.19:/home/pillar/rootfs console=${console}  init=${init} loglevel=${loglevel}
>saveenv 
>printenv
sun4i#printenv 
boot_fastboot=fastboot
boot_normal=fatload nand 0 0x48000000 uImage; bootm 0x48000000
boot_recovery=nand read 40007800 recovery;boota 40007800
bootcmd=run setargs load_script boot_normal
bootdelay=1
console=ttyS0,115200
ethact=emac
ethaddr=00:11:22:33:44:55
fastboot_key_value_max=0x8
fastboot_key_value_min=0x2
init=/init
load_script=fatload nand 0 43000000 script.bin
loglevel=8
mmc_root=/dev/mmcblk0p7
nand_root=/dev/nandd
recovery_key_value_max=0x13
recovery_key_value_min=0x10
setargs=setenv bootargs root=/dev/nfs ip=192.168.2.7:196.168.2.1:255.255.255.0:::eth0 nfsroot=192.168.2.19:/home/pillar/rootfs console=ttyS0,115200 init=/init loglevel=8
stderr=serial
stdin=serial
stdout=serial
 
Environment size: 736/131068 bytes

192.168.2.19 is the IP of the NFS server.
Reboot the board, we can see the board boots from the server:

to see photo

via :

http://learn.linksprite.com/pcduino/pcduino-embedd...