How to Install RTAI on Axis ETRAX 100LX

There already exists a document describing in detail how to install the Developer Board LX Software. It can be found at http://developer.axis.com/doc/software/devboard_lx/install-howto.html. You can also take a look at the Getting Started Guide if your bord is not up and running yet.

This document describes how to set up RTAI on ETRAX 100LX and the documents can therefore differ in som details, particularly the kernel version used. If you run into problems that relate to setting up the card or booting it, then you can consult the above document. But otherwise this one should be ok.

Note

Install the compiler

• cris-dist-1.25-1.i386.rpm
• cris-dist_1.25-1_i386.deb
• cris-dist-1.25.tar.gz

Install the software and compile a normal Linux kernel

• devboard_lx-R2_1_0.tgz from http://developer.axis.com/download/devboard_lx/latest/
• linux-2.4.19.tar.gz from http://developer.axis.com/download/linux/linux-2.4.19.tar.gz
• linux.2.4.19-diff.tgz from http://developer.axis.com/download/linux/linux.2.4.19-diff.tgz

Do not try to run ./install, the script assumes that you have a 2.4.14 kernel which you do not have.

cd ~
tar xvzf devboard_lx-R2_1_0.tgz
cd axis/devboard_lx/os
tar xvzf linux-2.4.19.tar.gz
mv linux-2.4.19 linux
cd ~
tar xvzf linux.2.4.19-diff.tgz
cp linux-2_4_19.diff axis/devboard_lx
cp kernelconfig axis/devboard_lx/kernelconfig
cd axis/devboard_lx
cat linux-2_4_19.diff | patch -d os/linux -Np1
rm kernelconfig.latest
cp kernelconfig os/linux/.config

You have now set up everything you need to be able to compile your own Linux kernel and flash the board with it. If you want you can now configure your linux kernel in the normal way or use the default configuration. To compile the tools and kernel perform the following steps:

. ./init_env
make tools
make kernel
make cris-axis-linux-gnu
make install
make images

If everything is ok, you should now be able to flash the board with the new kernel. Remember to put your board in flash mode by pressing the reboot button while holding down the boot button. Look at this image if you are in doubt. A describtion of the network boot process can be found at http://developer.axis.com/doc/software/tools/network_boot.html.

./flashit

In the future when recompiling the kernel, you do not have to perform all of the above steps. It is sufficient if you do like this.

cd os/linux
make menuconfig
cd ..
cd ..
. ./init_env
make kernel
make images
./flashit

RTAI

• Download rtai from http://www.efd.lth.se/~d98mad/rtai-24.1.9-cris.tar.gz and unpack it.
  
  tar xvzf rtai-24.1.9-cris.tar.gz
• Apply the kernel patch.
  $RTAIDIR is the directory where you have extracted your RTAI sources.
  $KERNELDIR is the directory where you have extracted your kernel sources.
  
  cd $KERNELDIR
  patch -p1 < $RTAIDIR/rtai-24.1.9/patches/patch-2.4.19-cris-rthal
  
• Configure the kernel. Remember to enable RTHAL, the Real-Time Hardware Abstraction Layer.
  
  make menuconfig
• Configure RTAI.
  
  cd $RTAIDIR
  make menuconfig
  
  Enter the location of your patched kernel source and press enter.
  A working configuration could for example look like this:

  #    [ ] Prompt for experimental code
  #    --- Schedulers
  #    <M> UP scheduler
  #    --- Features
  #    [ ] Enable floating point support
  #    --- Subsystems
  #    <M> POSIX API
  #    <*> RT memory manager
  #    <M> FIFOs
  #    --- Communication
  #    [ ] Real-Time serial driver (rt_com)
  #    --- Tests and Examples 
  #    [*] Compile tests
  #    [*] Compile examples
  

• Build the RTAI modules
  
  make dep && make
• Make sure that rtai.o will be linked into the Linux kernel.
  

  cd $KERNELDIR
  mkdir rtai
  cd rtai
  cp $RTAIDIR/rtaidir/rtai.o
  

  If you get an error when running make kernel saying that no such file exists, even though you have copied it, then you have run make clean either explicitly or implicitly. One workaround is to copy the file again, wait for the scripts to remove it and then copy it before the linking starts.
• Compile the kernel, make the images and flash the card with the RTAI enabled kernel.

  cd ~/axis/devboard_lx/
  make kernel
  make images
  . ./init_env
  ./flashit
  

• RTAI will not be enabled if no module using it is loaded. Look at the examples to see how to enable RTAI.

Kernel config options to be able to work with RTAI

• "Enable loadable module support" must be set to Yes
  
• "Real-Time Hardware Abstraction Layer" must be set to Yes.
• "Disable cascaded-mode timers in RTAI" should be set to No
• "Enable ETRAX fast timer API" should be set to No.
• "Etrax-100-LX-v2" should be enabled if you have a v2 card (which you probably have).

insmod, rmmod and lsmod

Related manuals from Axis