Boot BeagleBone black with NFS

Hi Foks.! Welcome to my blog.

To make this happen I have been through many blogs, some where help-full, out of my experimentation  here are the steps to boot kernel with NFS. This procedure is applicable to any board that can boot till u-boot prompt. I am using Beagle Bone Black as an example.

To get started we need the following:

• BeagleBoneBlack (BBB) board
• Linux distribution based host machine ( I have Ubuntu 14.04)
• CP2102 USB2.0 to TTL UART serial converter module.
• Ethernet cable
• 100-240V to 5V-1.0 or 2.0A  adapter/converter
• TFTP & NFS server 
• kernel & buildroot source
• I am using filesystem generated from buildroot

Serial Connection:

Locate the 6-pin header on BBB, written as "J1" below the first pin on the PCB as show in the below picture.

 

• J1 = GND (Ground)
• J4 = RXD (Receive Data)
• J5 = TXD (Transmit Data)

 

CP2102 USB2.0 to TTL UART serial converter

Connect J4 (RXD) to TXD line of  CP2102 USB2.0 to TTL UART serial converter
Connect J5 (TXD) to RXD line of  CP2102 USB2.0 to TTL UART serial converter
Connect J1 (GND) to GND line of  CP2102 USB2.0 to TTL UART serial converter

This makes the serial console setup ready.

Initialize Build Environment : 

gvk51@gvk:~$ sudo apt-get install git u-boot-tools g++ gawk lzop texinfo git-core build-essential libncurses5-dev gcc-arm-linux-gnueabi

Install all the mentioned packages for making build smooth.

Download Kernel Source :

gvk51@gvk:~$ cd src
gvk51@gvk:~/src$ git clone git://github.com/beagleboard/kernel.git
gvk51@gvk:~/src$ cd kernel
gvk51@gvk:~/src/kernle$ git checkout 3.8
gvk51@gvk:~/src/kernle$ ./patch.sh
gvk51@gvk:~/src/kernle$ cp configs/beaglebone kernel/arch/arm/configs/beaglebone_defconfig
gvk51@gvk:~/src/kernle$ wget http://arago-project.org/git/projects/?p=am33x-cm3.git\;a=blob_plain\;f=bin/am335x-pm-firmware.bin\;hb=HEAD -O kernel/firmware/am335x-pm-firmware.bin

Download Buildroot Source :

gvk51@gvk:~$ cd src
gvk51@gvk:~$ git clone git://git.buildroot.net/buildroot

Download the buildroot config from the below link, it is built for ARM-little endian-cortex-A8 choosing 3.8.13 kernel version headers, and build the cross compiler toolchain by itself, copy nfs_defconfing file to buildroot/configs folder

From buildroot disable the udhcp network utility of the busy-box, other wise while booting it tries to get a dynamic IP address causing the nfs failure. below are the steps to disable.

$ cd src/buildroot
$ make busybox-menuconfig

Goto "Networking Utilities  --->" & disable the following

• udhcp client for DHCPv6 (udhcpc6) 
• udhcp server (udhcpd)
• udhcp client (udhcpc) 

save & eixt
$ make busybox-update-config

Click to Download buildroot Config file nfs_defconfig

Building kernel & buildroot from source:

Assuming build environment is successfully done, we now start building the kernel & buildroot root file-system from source.

gvk51@gvk:~/src$ mkdir images
gvk51@gvk:~/src$ mkdir logs
gvk51@gvk:~/src$ cd kernel/kernel
gvk51@gvk:~/src/kernel/kernel$ make beaglebone_defconfig
gvk51@gvk:~/src/kernel/kernel$ make -j4 uImage dtbs 2>&1 | tee ~/src/logs/kernel.txt
gvk51@gvk:~/src/kernel/kernel$ make -j4 modules
gvk51@gvk:~/src/kernel/kernel$ make uImage-dtb.am335x-boneblack
gvk51@gvk:~/src/kernel/kernel$ cp ./arch/arm/boot/uImage-dtb.am335x-boneblack ~/src/images
gvk51@gvk:~/src/kernel/kernel$ cd ~/src/buildroot
gvk51@gvk:~/src/buildroot$ make nfs_defconfig 
gvk51@gvk:~/src/buildroot$ make 2>&1 | tee ~/src/logs/fs.txt
gvk51@gvk:~/src/buildroot$ cp ./output/images/rootfs.tar.gz ~/src/images

This completes the kernel & build root building, important files we need here are uImage-dtb.am335x-boneblack & rootfs.tar.gz

I assume that you have booted to u-boot prompt on BBB, the boot media can be either uSD or eMMC or UART. For booting from UART, check the link BBB booting from UART

Here we download the kernel image from tftp & rootfs is over the network.


Installing TFTP server on u-buntu:

To install the tftpd package, run the following: 

gvk51@gvk:~$ sudo apt-get install tftpd

To configure the TFTP server, create /etc/xinetd.d/tftp with the following contents: 

service tftp
{
protocol        = udp
port            = 69
socket_type     = dgram
wait            = yes
user            = nobody
server          = /usr/sbin/in.tftpd
server_args     = /tftpboot
disable         = no
}

Run the following to create the TFTP server's base directory and allow anyone to access it:

gvk51@gvk:~# sudo mkdir /tftpboot
gvk51@gvk:~# sudo chmod -R 777 tftpboot
gvk51@gvk:~# sudo chown -R nobody /tftpboot

copy the uImage-dtb.am335x-boneblack to /tftpboot

gvk51@gvk:~$ cp ~/src/images/uImage-dtb.am335x-boneblack

Restart xinetd deamon to enable the server:

gvk51@gvk:~$ sudo /etc/init.d/xinetd restart

Installing NFS services & Tools:

On Ubuntu, Debian, and similar systems, the services and tools required by an NFS server can be installed with the following command:

gvk51@gvk:~$ sudo apt-get install nfs-kernel-server nfs-common portmap

setup the network file system

gvk51@gvk:~# sudo mkdir /srv/nfs/bbb
gvk51@gvk:~# sudo tar -C /srv/nfs/bbb -xzf ~/src/images/rootfs.tar.gz
gvk51@gvk:~# cd /srv/nfs/bbb
gvk51@gvk:/srv/nfs/bb# sudo ln -s bin/busybox init

Add the below line to /etc/exports file, assuming BBB is having a static IP say 192.168.19.112

/srv/nfs/bbb 192.168.19.112(rw,sync,no_root_squash,no_subtree_check)

gvk51@gvk:~# sudo gedit /etc/exports

export the NFS directories and restart the service

gvk51@gvk:~# sudo exportfs -a
gvk51@gvk:~# sudo exportfs -rv
gvk51@gvk:~# sudo service nfs-kernel-server start

 for more details about tftp, nfs  check these links LINK1 LINK2 LINK3

Assuming you are at the u-boot prompt.

IP address of the Ubuntu host machine running tftp & nfs is 192.168.19.144

Hit any key to stop autoboot:  0
U-Boot#
U-Boot# setenv ipaddr 192.168.19.112
U-Boot# ping 192.168.19.144
link up on port 0, speed 100, full duplex
Using cpsw device
host 192.168.19.144 is alive
U-Boot# setenv serverip 192.168.19.144
U-Boot# tftpboot ${kloadaddr} uImage-dtb.am335x-boneblack
link up on port 0, speed 100, full duplex
Using cpsw device
TFTP from server 192.168.19.144; our IP address is 192.168.19.112
Filename 'uImage-dtb.'.
Load address: 0x82000000
Loading: #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     #################################################################
     ###########
     911.1 KiB/s
done
Bytes transferred = 4382407 (42dec7 hex)
U-Boot# setenv bootargs console=ttyO0,115200n8 root=/dev/nfs rw nfsroot=192.168.19.144:/srv/nfs/bbb/,nolock, wsize=1024, rsize=1024 rootwait init=/linuxrc rootdelay=5 ip=192.168.19.112
U-Boot# bootm ${kloadaddr}
## Booting kernel from Legacy Image at 82000000 ...
   Image Name:   Linux-3.8.13-00770-gc0eeacb-dirt
   Created:      2015-08-06   6:27:40 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    4382343 Bytes = 4.2 MiB
   Load Address: 80008000
   Entry Point:  80008000
   Verifying Checksum ... OK
   Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0x0
.
.
.
.
[    9.742832] Freeing init memory: 216K
Starting logging: OK
Initializing random number generator... done.
Starting network...
ifup: applet not found
Starting dropbear sshd: OK

Welcome to Buildroot over NFS
root login:

Click to Download BBB NFS Kernel Boot Log

Please leave your comments, that will be encouraging :)