Developing your AOS project on Linux

Many students have Linux machines which they would like to be able to use to work away from the labs. The following is a guide as to how to set up the necessary drivers/software. These instructions will be debian specific in some spots (e.g. setting up the tftp server) but they should at least give you an idea of how to set up other distributions.

The components you will need to install are:

• Cross compilers
• Driver for the NSLU2's USB->serial converter
• A serial terminal program (we use minicom, conserver or seyon)
• TFTP server
• time server
• An NFS server/share
• netcat
• nslu2-util

Once installed, the installation can be tested by following the milestone 0 instructions. Some parts of this procedure are un-tested.

Cross compilers

Crosstool is a system which will automagically build cross-compilers. Prior to crosstool, building cross-compilers was a fairly horrible process.

You can either try using this pre-compiled cross-compiler tarball (built on a i386 Debian testing host, unpack into /opt/crosstool), or otherwise follow these steps:

1. Obtain the version 0.42 of crosstool (there are reports that the latest version doesn't work with these instructions): http://kegel.com/crosstool
2. gunzip and tar xvf: tar xvfz crossstool-0.42.tar.gz
3. Edit the build script: emacs demo-armv5b-softfloat.sh. Comment out the 'eval' lines and add: eval `cat armv5b-softfloat.dat gcc-3.4.5-glibc-2.3.5.dat` sh all.sh --notest
4. sudo mkdir crosstool; sudo chown $USER:$USER /opt/crosstool
5. Run the build script. ./demo-armv5b-softfloat.sh Go to bed.
6. When you get up, you should have a toolchain in /opt/crosstool/gcc-3.4.5-glibc-2.3.5/armv5b-softfloat-linux/bin/. Add this directory to your PATH.

Installing drivers

You need device drivers for the USB to Ethernet dongle, and the FT232RL USB-Serial converter. Fortunately, these drivers are in the linux kernel and are compiled by most modern distributions, so you should be able to plug them in and see messages from the drivers via dmesg.

The modules required are:

• asix : USB-to-Ethernet
• ftdi_sio : USB-to-Serial

If you don't have hotplug set up correctly, you may need to use use modprobe to load the modules. e.g. modprobe asix. You probably want to get this all working automatically, as it is in the labs.

At this stage, we assume a working serial converter and ethernet port. The serial converter is assumed to use device /dev/ttyUSB0 and the ethernet port is assumed to use eth1. Substitute below if your setup varies (e.g. if you are using a real Ethernet port or network).

Setting up the network

The AOS board expects to find a host at 192.168.0.1. You can change this temporarily in the bootloader, but its easiest to set up your host to be at this address. This is not a problem if you are using an independent network provided by the USB to Ethernet dongle.

If your USB to Ethernet dongle is using eth1 (note that it will simply get the next unused ethX interface - i.e. if your wired Ethernet is eth0, wireless is eth1, then the USB-Ethernet converter will be eth2. This should show up in the output of dmesg).

ifconfig eth1 192.168.0.1 up

Setting up the TFTP server

The bootloader will download your software image from a tftp server running on your host. So you need to set one up:

apt-get install tftpd

Edit your /etc/inetd.conf. Change the following line to reflect the location of the directory which you want to use as your tftp root. (In this case it is /tftpboot).

tftp            dgram   udp     wait    nobody  /usr/sbin/tcpd 
/usr/sbin/in.tftpd /tftpboot

You may need to restart inetd at this point using /etc/init.d/inetd restart

You will also need to adjust your handy Makefile if you want it to automatically copy the bootimg.bin file to the tftpboot directory. The variable to look for is: TFTPROOT

Setting up the time server

Uncomment the following line in /etc/inetd.conf :

#time           dgram   udp     wait    root    internal

Set up an NFS share

Install the NFS server:

daves@gedanken:~$ apt-get install nfs-kernel-server nfs-common portmap

/tftpboot 192.168.0.2(rw,no_root_squash,insecure)

Install the NSLU2 utility program

It is necessary to be able to control the NSLU2 using a utility program. It controls the reset line, allowing the NSLU2 to boot once a serial console has been opened.

Download the source code. Uncompress it, make, and copy the resulting executable to a directory in your $PATH (or add the nslu2-util directory to your $PATH).

Install other required software

Install the following packages:

apt-get install minicom netcat wireshark scons=0.96.93 make mercurial

Note on SCons versions

Note that you will need an old version of SCons, 0.96.93 (or probably something similar) to successfully build the project. If you can't find an appropriate package for your distribution, we suggest downloading this source and building it yourself.

Patches to fix the build with new versions of SCons will be happily accepted!