User`s manual

Getting Started With Linux on the LPC3250 OEM Board Page 29
Copyright 2009 © Embedded Artists AB Rev A
In the default environment there is a variable named loadkernel_nand which illustrates how to
load the kernel from NAND flash.
loadkernel_nand=nboot.jffs2 $(loadaddr) 0x0 $(nand_kernel_off)
1. The nboot command is used to load the kernel from NAND device 0x0 and offset
nand_kernel_off to SDRAM at address loadaddr .
If you would like to load the kernel from NAND flash make sure that the loadkernel variable
contains the content of the loadkernel_nand variable.
uboot> setenv loadkernel $(loadkernel_nand)
uboot> saveenv
4.3.4 Root File System NFS Mounted
During the development phase of your Linux system it is convenient to be able to easily update the
root file system without having to transfer the file system to the development board. Using NFS
(Network File System) will allow you to do this.
1. Make sure you have NFS setup on your development computer as described in section 3.2.5
or section 3.3.5.
2. Set the rootpath variable in the u-boot environment to point to the location of your
exported root file system directory.
rootpath=/home/user/ltib/rootfs
3. Use the nfsboot variable to boot Linux. This variable will setup the bootargs variable in
a way where Linux use an NFS mounted root file system.
nfsboot=setenv bootargs root=/dev/nfs rw nfsroot=$(serverip):$(rootpath)
ip=$(ipaddr) ea_ethaddr=$(ethaddr) console=ttyS0,115200n8;run
loadkernel;bootm $(loadaddr)
4.3.5 Root File System in NAND Flash
The root file system can be stored in the large NAND flash available on the LPC3250 OEM Board. This
is typically the place where the root file system will be placed after the development phase, allowing
the Linux system to be more stand-alone.
1. The first step is to update the NAND flash with the root file system. Two variables have been
setup to load the root file system from either a TFTP server or from a USB memory stick. If
you have problems loading the file system image from a USB memory stick, please read
section 4.5.1 to see if this solves your problem.
loadrootfs_tftp=tftpboot $(loadaddr) rootfs.jffs2
loadrootfs_usb=usb start;fatload usb 0 $(loadaddr) rootfs.jffs2;usb stop
2. Set the loadrootfs variable to the content of either the loadrootfs_tftp or
loadrootfs_usb variable as in the example below.
uboot> setenv loadrootfs $(loadrootfs_usb)
uboot> saveenv