LinuxNfsRoot < DULG

%SECTION0{name=LinuxNfsRoot}% Networked Operation with Root Filesystem over NFS

This section will show how to boot the target into Linux with no more
than U-Boot residing on it.  For this we will use the =tftp= command
of U-Boot to transfer a Linux kernel and boot it with the NFS
rootfilesystem provided by the ELDK.

For this to work, we rely on some U-Boot environment variables to be
set up correctly, i.e. the network parameters, the names of files
to transfer via tftp and last but not least some scripts easing the
assembly of the Linux command line.  The whole process is packaged up
into one script shown before we actually execute it.

Note that the Linux kernel will also output the command line used, so
you can easily check if everything worked like expected.  The command
line in this example passes at least the following information to the:

   * =root<NOP>=/dev/nfs rw=: the root filesystem will be mounted
     using NFS, and it will be writable.

   * =nfsroot<NOP>=%SERVERIP%:%ROOTPATH%=: the NFS server has the
     IP address %SERVERIP%, and exports the directory
     _%ROOTPATH%_ for our system to use as root
     filesystem.

   * =ip<NOP>=%IPADDR%:%SERVERIP%:%GATEWAYIP%:%NETMASK%:%HOSTNAME%::off=: the
     target has the IP address =%IPADDR%=; the NFS server is
     =%SERVERIP%=; there is a gateway at IP address =%GATEWAYIP%=; the
     netmask is =%NETMASK%= and our hostname is =%HOSTNAME%=. The first
     ethernet interface (=eth0=) willbe used, and the Linux kernel
     will immediately use this network configuration and not try to
     re-negotiate it (IP autoconfiguration is =off=).

See _Documentation/nfsroot.txt_ in you Linux kernel
source directory for more information about these parameters and other
options.

%SECTION1{name=LinuxBootlog}% Bootlog of tftp'd Linux kernel with Root Filesystem over NFS

%INCLUDE{DULGData_%BOARD%.LinuxBootNetNfs}%
7.4. Boot Arguments Unleashed		1. Abstract		7.6. Boot from Flash Memory
Prev		Home		Next