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ARM/N900/Install/NFS

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(Instructions fixed and somewhat restructured)
Line 1: Line 1:
 +
This page describes howto make N900 boot a MeeGo root filesystem from your host (PC) using USB networking. Two different approaches are described:
 +
* using initrd (no compilation of any sw components required)
 +
* using customized kernel (requires kernel recompilation)
 +
Initrd is the preferred method.
 +
== Requirements ==  
== Requirements ==  
-
* Environment for building ARM binaries
 
* USB networking
* USB networking
 +
* a MeeGo rootfs image extracted
-
== Steps for NFS-root ==
+
== Preparing the root filesystem ==
First, you have to get/make a MeeGo rootfs image. You can download a pre-built image ([[ARM/Meego_images_for_N900]]) or create your own ([[ARM/Creating ARM image using MeeGo Image Creator]]). Then you must make the (unpacked) rootfs available in a suitable location on your host system (e.g. /home/nfs/rootfs).
First, you have to get/make a MeeGo rootfs image. You can download a pre-built image ([[ARM/Meego_images_for_N900]]) or create your own ([[ARM/Creating ARM image using MeeGo Image Creator]]). Then you must make the (unpacked) rootfs available in a suitable location on your host system (e.g. /home/nfs/rootfs).
 +
 +
If you're creating your own rootfs image, you might want to install busybox there. So that you can easily get busybox for your initrd.
Next, make sure you have NFS server installed on your host and export the rootfs. In Ubuntu:
Next, make sure you have NFS server installed on your host and export the rootfs. In Ubuntu:
Line 12: Line 19:
  exportfs -v -a
  exportfs -v -a
 +
Currently, one hack for the (readymade) N900 rootfs image is needed. The nokia-usb-networking (provided by nokia-n900-configs package) messes up the networking when trying to use nfsroot. Simply remove it from the current default runlevel of the MeeGo rootfs:
 +
rm /home/nfs/rootfs/etc/rc.d/rc3.d/S50nokia-usb-networking
-
Then, you have to recompile kernel for N900. You must enable (built inside kernel, thus select '*', not 'M'):
+
== Method 1: NFS-Root with initrd ==
-
* USB Gadget support (Device drivers -> USB Support -> USB Gadget support)
+
This method involves using busybox from MeeGo and does not require kernel recompilation. You can more easily keep in sync with the MeeGo kernel.
-
  * USB Gadget drivers (Device drivers -> USB Support -> USB Gadget support -> USB Gadget drivers)
+
-
    * Ethernet gadget
+
-
  * RNDIS Support (Device drivers -> USB support -> USB Gadget support -> RNDIS support)
+
-
* NFS support (File systems -> Network File systems -> NFS client support)
+
-
  * NFS-Root support (File systems -> Network File systems -> NFS client support -> Root file system on NFS)
+
-
* IP kernel autoconf (Networking support -> Networking options -> IP: kernel level autoconfiguration)
+
-
  * all sub-options
+
-
 
+
-
Compile and install modules
+
-
make
+
-
make modules_install INSTALL_MOD_PATH=/home/nfs/rootfs
+
-
 
+
-
 
+
-
After compilation is finished you can boot the new kernel with (assuming 192.168.2.14 is your host)
+
-
flasher -k arch/arm/boot/zImage -l -b"init=/sbin/preinit ip=192.168.2.15::192.168.2.14 root=/dev/nfs nfsroot=192.168.2.14:/home/nfs/rootfs rootdelay=2 rw console=ttyMTD console=tty0"
+
-
 
+
-
 
+
-
You can also hard code the kernel command line options as default when recompiling the kernel (Boot options -> default kernel command string). And further, you can of course flash the new kernel to the device. But still, you have to override the Nolo command line options with flasher
+
-
 
+
-
flasher -b
+
-
 
+
-
== NFS-Root with initrd ==
+
-
'''OBS: the switch_root step in the script in the end does not seem to work with the latest kernel, you could try it though. Pivot root seems to work.'''
+
-
 
+
-
This method involves using busybox and does not require kernel recompilation. You can more easily keep in sync with the MeeGo kernel.
+
-
 
+
-
=== Busybox ===
+
-
The easiest way to make it working is to build a static binary. Get Busybox sources:
+
-
 
+
-
wget http://busybox.net/downloads/busybox-1.16.0.tar.bz2
+
-
 
+
-
or
+
-
 
+
-
git clone git://git.busybox.net/busybox
+
-
 
+
-
 
+
-
Unpack/go to busybox source directory. And edit configuration and compile.
+
-
 
+
-
cd  busybox
+
-
make defconfig
+
-
make menuconfig
+
-
+
-
# Enable static build (Busybox settings -> Build options -> Buidld BusyBox as a static binary)
+
-
make CROSS_COMPILE=arm-linux-
+
-
make install CROSS_COMPILE=arm-linux- CONFIG_PREFIX=./initrd
+
-
Now you have an initial busybox environment installed in busybox/initrd.
+
=== Preparing initrd directory ===
 +
First, you have to create a directory for preparing initrd. We'll create that under the rootfs directory (but you could create it anywhere you like, of course).
 +
  mkdir /home/nfs/rootfs/initrd
-
=== Preparing initrd ===
+
You need some initial directories:
-
To make the initrd bootable and usable you need some preparations. First, make some
+
  cd /home/nfs/rootfs/initrd
-
Initial directories:
+
mkdir bin
-
  cd initrd
+
mkdir sbin
  mkdir proc
  mkdir proc
  mkdir sys
  mkdir sys
Line 80: Line 46:
  cp -a /dev/tty0 dev/
  cp -a /dev/tty0 dev/
  cp -a /dev/zero dev/
  cp -a /dev/zero dev/
-
 
Copy kernel modules from your rootfs to the initrd (be sure to use correct kernel version):
Copy kernel modules from your rootfs to the initrd (be sure to use correct kernel version):
  cp -r /home/nfs/rootfs/lib/modules/2.6.28-19.1-n900/ lib/modules/
  cp -r /home/nfs/rootfs/lib/modules/2.6.28-19.1-n900/ lib/modules/
 +
=== Installing Busybox ===
 +
As the next step, you need Busybox. If you have busybox installed in you rootfs, you can simply:
 +
cp /home/nfs/rootfs/sbin/busybox bin/
 +
If you don't, you can get the binary e.g. by fetching the busybox rpm package and extracting the binary from there
 +
mkdir tmp
 +
cd tmp
 +
wget http://repo.meego.com/MeeGo/devel/trunk/repo/arm/os/armv5tel/busybox-1.16.0-2.5.armv5tel.rpm
 +
rpm2cpio busybox-1.16.0-2.5.armv5tel.rpm | cpio -id
 +
cp sbin/busybox /home/nfs/rootfs/initrd/bin/
 +
cd ..
 +
rm -rf tmp
 +
 +
Now, you have the busybox binary installed. Currently, MeeGo does not have a statically compiled version of Busybox. Thus, you need some libraries as well:
 +
cp /home/nfs/rootfs/lib/ld-linux.so.3 lib/
 +
cp /home/nfs/rootfs/lib/libc.so.6 lib/
 +
cp /home/nfs/rootfs/lib/libm.so.6 lib/
 +
 +
Last, you need to set up some links to the busybox binary:
 +
cd bin
 +
ln -s busybox sh
 +
ln -s busybox mount
 +
ln -s busybox modprobe
 +
ln -s busybox sleep
 +
ln -s busybox ifconfig
 +
ln -s busybox echo
 +
ln -s busybox umount
 +
ln -s busybox pivot_root
 +
ln -s busybox exec
 +
ln -s busybox cd
 +
ln -s busybox ls
 +
ln -s busybox chroot
 +
cd ..
 +
 +
Now, you're done with Busybox.
 +
=== Making initrd to boot automatically ===
Next, make a script for doing the actual NFS-rooting and :
Next, make a script for doing the actual NFS-rooting and :
  vim autonfsroot.sh
  vim autonfsroot.sh
Line 93: Line 93:
  ln -s ../autonfsroot.sh sbin/init
  ln -s ../autonfsroot.sh sbin/init
-
 
+
Here's a simple example of autonfsroot.sh
-
Here's my autonfsroot.sh
+
  #!/bin/sh
  #!/bin/sh
  echo "Doing mounts..."
  echo "Doing mounts..."
Line 121: Line 120:
   
   
  echo "Switching to nfsroot..."
  echo "Switching to nfsroot..."
-
  # MLE: switch_root not working for me currently, for some reason
+
  # switch_root does not seem to be working with cramfs
  #exec switch_root /mnt /sbin/init
  #exec switch_root /mnt /sbin/init
  cd /mnt
  cd /mnt
Line 127: Line 126:
  exec chroot . /sbin/init
  exec chroot . /sbin/init
 +
Of course, you could do more elaborate scripting, e.g. add automatic kernel command line parsing/analysis, but that's not covered here.
-
=== Making initrd and booting ===
+
=== Making initrd image and booting ===
N900 requires cramfs initrd images. This is a bootloader restriction. Go back to the directory containing the initrd dir and then:
N900 requires cramfs initrd images. This is a bootloader restriction. Go back to the directory containing the initrd dir and then:
  cd ..
  cd ..
Line 137: Line 137:
Voilá, you should see MeeGo booting.
Voilá, you should see MeeGo booting.
 +
 +
 +
 +
== Method 2: NFS-Root with custom kernel ==
 +
As a pre-requisite, you have to have environment for cross-building ARM binaries.
 +
 +
Then, you have to recompile kernel for N900. You must enable (built inside kernel, thus select '*', not 'M'):
 +
* USB Gadget support (Device drivers -> USB Support -> USB Gadget support)
 +
  * USB Gadget drivers (Device drivers -> USB Support -> USB Gadget support -> USB Gadget drivers)
 +
    * Ethernet gadget
 +
  * RNDIS Support (Device drivers -> USB support -> USB Gadget support -> RNDIS support)
 +
* NFS support (File systems -> Network File systems -> NFS client support)
 +
  * NFS-Root support (File systems -> Network File systems -> NFS client support -> Root file system on NFS)
 +
* IP kernel autoconf (Networking support -> Networking options -> IP: kernel level autoconfiguration)
 +
  * all sub-options
 +
 +
Compile and install modules
 +
make
 +
make modules_install INSTALL_MOD_PATH=/home/nfs/rootfs
 +
 +
 +
After compilation is finished you can boot the new kernel with (assuming 192.168.2.14 is your host)
 +
flasher -k arch/arm/boot/zImage -l -b"init=/sbin/preinit ip=192.168.2.15::192.168.2.14 root=/dev/nfs nfsroot=192.168.2.14:/home/nfs/rootfs rootdelay=2 rw console=ttyMTD console=tty0"
 +
 +
 +
You can also hard code the kernel command line options as default when recompiling the kernel (Boot options -> default kernel command string). And further, you can of course flash the new kernel to the device. But still, you have to override the Nolo command line options with flasher
 +
 +
flasher -b

Revision as of 08:25, 21 April 2010

This page describes howto make N900 boot a MeeGo root filesystem from your host (PC) using USB networking. Two different approaches are described:

  • using initrd (no compilation of any sw components required)
  • using customized kernel (requires kernel recompilation)

Initrd is the preferred method.

Contents

Requirements

  • USB networking
  • a MeeGo rootfs image extracted

Preparing the root filesystem

First, you have to get/make a MeeGo rootfs image. You can download a pre-built image (ARM/Meego_images_for_N900) or create your own (ARM/Creating ARM image using MeeGo Image Creator). Then you must make the (unpacked) rootfs available in a suitable location on your host system (e.g. /home/nfs/rootfs).

If you're creating your own rootfs image, you might want to install busybox there. So that you can easily get busybox for your initrd.

Next, make sure you have NFS server installed on your host and export the rootfs. In Ubuntu: 

apt-get install nfs-kernel-server
echo '/home/nfs      192.168.*(rw,no_root_squash,no_subtree_check)' >> /etc/exports
exportfs -v -a

Currently, one hack for the (readymade) N900 rootfs image is needed. The nokia-usb-networking (provided by nokia-n900-configs package) messes up the networking when trying to use nfsroot. Simply remove it from the current default runlevel of the MeeGo rootfs: 

rm /home/nfs/rootfs/etc/rc.d/rc3.d/S50nokia-usb-networking

Method 1: NFS-Root with initrd

This method involves using busybox from MeeGo and does not require kernel recompilation. You can more easily keep in sync with the MeeGo kernel.

Preparing initrd directory

First, you have to create a directory for preparing initrd. We'll create that under the rootfs directory (but you could create it anywhere you like, of course). 

 mkdir /home/nfs/rootfs/initrd

You need some initial directories: 

cd /home/nfs/rootfs/initrd
mkdir bin
mkdir sbin
mkdir proc
mkdir sys
mkdir dev
mkdir mnt
mkdir -p lib/modules

Some device nodes are needed by the kernel (note, these must be run as root to preserve device node properties): 

cp -a /dev/console dev/
cp -a /dev/null dev/
cp -a /dev/ram0 dev
cp -a /dev/tty dev/
cp -a /dev/tty0 dev/
cp -a /dev/zero dev/

Copy kernel modules from your rootfs to the initrd (be sure to use correct kernel version): 

cp -r /home/nfs/rootfs/lib/modules/2.6.28-19.1-n900/ lib/modules/

Installing Busybox

As the next step, you need Busybox. If you have busybox installed in you rootfs, you can simply: 

cp /home/nfs/rootfs/sbin/busybox bin/

If you don't, you can get the binary e.g. by fetching the busybox rpm package and extracting the binary from there 

mkdir tmp
cd tmp
wget http://repo.meego.com/MeeGo/devel/trunk/repo/arm/os/armv5tel/busybox-1.16.0-2.5.armv5tel.rpm
rpm2cpio busybox-1.16.0-2.5.armv5tel.rpm | cpio -id
cp sbin/busybox /home/nfs/rootfs/initrd/bin/
cd ..
rm -rf tmp

Now, you have the busybox binary installed. Currently, MeeGo does not have a statically compiled version of Busybox. Thus, you need some libraries as well: 

cp /home/nfs/rootfs/lib/ld-linux.so.3 lib/
cp /home/nfs/rootfs/lib/libc.so.6 lib/
cp /home/nfs/rootfs/lib/libm.so.6 lib/

Last, you need to set up some links to the busybox binary: 

cd bin
ln -s busybox sh
ln -s busybox mount
ln -s busybox modprobe
ln -s busybox sleep
ln -s busybox ifconfig
ln -s busybox echo
ln -s busybox umount
ln -s busybox pivot_root
ln -s busybox exec
ln -s busybox cd
ln -s busybox ls
ln -s busybox chroot
cd ..

Now, you're done with Busybox.

Making initrd to boot automatically

Next, make a script for doing the actual NFS-rooting and : 

vim autonfsroot.sh
# edit the script, an example is found below
chmod a+x autonfsroot.sh
rm sbin/init
ln -s ../autonfsroot.sh sbin/init

Here's a simple example of autonfsroot.sh 

#!/bin/sh
echo "Doing mounts..."
mount -t proc proc /proc
mount -t sysfs sysfs /sys

echo "Loading modules..."
modprobe sunrpc
modprobe auth_rpcgss
modprobe rpcsec_gss_krb5
modprobe nfs
modprobe phonet
modprobe g_nokia

sleep 2

echo "Configuring network interface..."
ifconfig usb0 192.168.2.15

echo "Mounting NFS..."
mount -t nfs -o nolock 192.168.2.14:/home/nfs/rootfs /mnt

echo "Unmounting proc and sys..."
umount /proc
umount /sys

echo "Switching to nfsroot..."
# switch_root does not seem to be working with cramfs
#exec switch_root /mnt /sbin/init
cd /mnt
pivot_root . mnt
exec chroot . /sbin/init

Of course, you could do more elaborate scripting, e.g. add automatic kernel command line parsing/analysis, but that's not covered here.

Making initrd image and booting

N900 requires cramfs initrd images. This is a bootloader restriction. Go back to the directory containing the initrd dir and then: 

cd ..
mkfs.cramfs -b 4096 -n meego_initrd ./initrd/ initrd.img

Now you can load your initrd with flasher and boot to nfs-root: 

flasher -n initrd.img -l -b"root=/dev/ram0"

Voilá, you should see MeeGo booting.


Method 2: NFS-Root with custom kernel

As a pre-requisite, you have to have environment for cross-building ARM binaries.

Then, you have to recompile kernel for N900. You must enable (built inside kernel, thus select '*', not 'M'): 

* USB Gadget support (Device drivers -> USB Support -> USB Gadget support)
  * USB Gadget drivers (Device drivers -> USB Support -> USB Gadget support -> USB Gadget drivers)
    * Ethernet gadget
  * RNDIS Support (Device drivers -> USB support -> USB Gadget support -> RNDIS support)
* NFS support (File systems -> Network File systems -> NFS client support)
  * NFS-Root support (File systems -> Network File systems -> NFS client support -> Root file system on NFS)
* IP kernel autoconf (Networking support -> Networking options -> IP: kernel level autoconfiguration)
  * all sub-options

Compile and install modules 

make
make modules_install INSTALL_MOD_PATH=/home/nfs/rootfs


After compilation is finished you can boot the new kernel with (assuming 192.168.2.14 is your host) 

flasher -k arch/arm/boot/zImage -l -b"init=/sbin/preinit ip=192.168.2.15::192.168.2.14 root=/dev/nfs nfsroot=192.168.2.14:/home/nfs/rootfs rootdelay=2 rw console=ttyMTD console=tty0"


You can also hard code the kernel command line options as default when recompiling the kernel (Boot options -> default kernel command string). And further, you can of course flash the new kernel to the device. But still, you have to override the Nolo command line options with flasher 

flasher -b
Retrieved from "http://wiki.meego.com/ARM/N900/Install/NFS"
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