[vc_row][vc_column][vc_column_text]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.[/vc_column_text][vc_tour][vc_tab title=”NFS Server” tab_id=”1396344123-1-77″][vc_column_text]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,

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

[/vc_column_text][/vc_tab][vc_tab title=”Modify Kernel” tab_id=”1396344123-2-51″][vc_column_text]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.[/vc_column_text][/vc_tab][vc_tab title=”Configure U-boot” tab_id=”1396346008260-2-7″][vc_column_text]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):

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:

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