Document:	NFS root filesystem

Copyright (c) 2007, Voipac Technologies a.s.


In this example assume that:

192.168.1.65 is NFS server address
192.168.1.49 is address assigned to vpac270 device

You should have enabled "IP: kernel level autoconfiguration"
CONFIG_IP_PNP and "IP: DHCP support" CONFIG_IP_PNP_DHCP.

Additionally it is required to enable "NFS file system support"
CONFIG_NFS_FS and "Root file system on NFS" CONFIG_ROOT_NFS.

You should setup your DHCP server to assign valid IP address, 
boot server address, and root path and image file name.

An example configuration for dnsmasq DNS/DHCP server:

> dhcp-host=00:01:02:03:04:05,net:devel,devel,192.168.1.49
> dhcp-boot=net:devel,zImage,etch,192.168.1.65            
> dhcp-option=net:devel,17,/tftpboot/rootfs

Alternatively you can assign IP addresses statically using u-boot 
"bootargs" environment variable and passing it to Linux kernel.

u-boot> set bootargs root=/dev/nfs rw nfsroot=192.168.1.65:/tftpboot/rootfs ip=192.168.1.49::::::

To setup NFS server install nfs-kernel-server package and create /etc/exports file.
Please check out manual for your preferred Linux distribution as it can be specific.

# /etc/exports: the access control list for filesystems which may be exported
#               to NFS clients.  See exports(5).
#
/tftpboot/rootfs	192.168.1.0/255.255.255.0(rw,sync,no_root_squash,no_subtree_check)

Unpack http://voipac.com/downloads/pxa/270/dimm/bin/linux/rootfs-mini1.tar.gz
to /tftpboot/rootfs and comment out eth0 interface configuration
in /tftpboot/rootfs/etc/network/interfaces, it will be already
configured by DHCP or assigned by kernel command line argument.

Download your compiled kernel image via TFTP, set "bootargs" variable 
(use "wtags" to pass "bootargs" to Linux kernel) and start the kernel.