EBC Exercise 08 Installing Development Tools

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Early in the class most of the exercises we will do will all run on the BeagleBoard. You'll be able to edit (gedit), compile (gcc) and run all on the Beagle. Later, when we start compiling the kernel [1] or the boot loader, (U-boot) you will need to cross compile on a Linux machine and copy the results to the Beagle.

The purpose of this exercise is to install all the tools needed for compiling on your host so they will be ready when you need them.

Instructions for building Ångström are given here; however there are a few changes you have to make. Here's what I did.

Install development environment

The step is to get the crosscompilers, etc. installed.

Get the setup scripts

First install git by running the following on your host computer.

$ sudo apt-get install git-core

(Here is a nice git tutorial. Take a look at it if you want to understand the commands that follow. We'll explore it in more depth in a later exercise.)

Then run the following to load the meta data.

I have everything in a ~/BeagleBoard, so here is how I setup things:

$ cd
$ mkdir -p BeagleBoard
$ cd BeagleBoard
$ git clone git://git.angstrom-distribution.org/setup-scripts oe
$ cd oe

(The git took 4.5 seconds.) This creates a directory for open embedded (oe) and gets the script to download Ångström. What files do you see?

Setting up for the BeagleBoard

Now let's setup local.conf for our needs:

$ gedit conf/local.conf

Add the following to the end of the file.

MACHINE ?= "beagleboard" 

Look at this block of lines:

# Make use of SMP and fast disks
PARALLEL_MAKE = "-j2"
BB_NUMBER_THREADS = "2"

Here you can tell it how many parallel threads to run. If you have several cores on your machine, make this number big. If you have only one core, you might be better performance setting it to 1. If you have no clue which value to pick, Gentoo users suggest 1 more than the number of cores in your computer. More details are here.

  • PARALLEL_MAKE sets the number "gcc" threads (same as make -j4 at compile time
  • BB_NUMBER_THREADS sets the number of bitbake threads, (one thread can be downloading, while another compiles)

To save you a lot of time, it is useful to disable locale generation for all but the one you need. Add this to local.conf

GLIBC_GENERATE_LOCALES = "en_US.UTF-8 en_GB.UTF-8 de_DE.UTF-8 fr_FR.UTF-8 pt_BR.UTF-8 es_ES.UTF-8 kn_IN.UTF-8 ml_IN.UTF-8 ta_IN.UTF-8"

Now run:

$ ./oebb.sh config beagleboard
$ ./oebb.sh update

This will bring in all the tools you need. The config took about 3.5 minutes on my machine, update took about 1 minute.

Build a small program

Before the first time you run bitbake you need to do the following to set up the environmental variables:

$ source ~/.oe/environment-oecore

Take a look in the file and see what it is doing.

$ less ~/.oe/environment-oecore

To see if everything is ready, run the following

$ bitbake nano

nano is a small editor. We really don't need nano, but if it can be compiled we know we have everything in place. I get the following error when I run the bitbake:

Pseudo is not present but is required, building this first before the main build
.
.
.
ERROR:  Poky's config sanity checker detected a potential misconfiguration.
    Either fix the cause of this error or at your own risk disable the checker (see sanity.conf).
    Following is the list of potential problems / advisories:

    Please install following missing utilities: C++ Compiler (g++),diffstat,texi2html,makeinfo,cvs,svn,chrpath

ERROR: Execution of event handler 'check_sanity_eventhandler' failed

So, some programs are missing. Install them with:

$ sudo apt-get install g++ diffstat texi2html texinfo cvs subversion chrpath help2man diffstat texi2html cvs texinfo subversion gawk

This took just a few minutes.

Now run:

$ bitbake nano

This will take a while. Mine first said it has 77 tasks to do. Once those were done it had 1113 tasks.

Below is a table of the times from last year. Add your bitbake time to this year's table.

Initial bitbake nano Winter 2011-2012 runtimes
Processor Settings Run Time
8 Core virtual machine PARALLEL_MAKE = "-j8"
BB_NUMBER_THREADS = "8"
2.5 hours
Intel Core 2 Duo T7800, 2.60 GHz PARALLEL_MAKE = "-j2"
BB_NUMBER_THREADS = "2"
1:55
Initial bitbake nano 2011 runtimes
Processor Settings Run Time
Dell E521 with AMD Athlon 64 dual-core PARALLEL_MAKE = "-j4"
BB_NUMBER_THREADS = "4"
Psyco? Yes.
1.5 hours
Intel Core 2 Duo T7800, 2.60 GHz PARALLEL_MAKE = "-j1"
BB_NUMBER_THREADS = "1"
Psyco? No.
1:46
Intel Core 2 Duo T7800, 2.60 GHz PARALLEL_MAKE = "-j4"
BB_NUMBER_THREADS = "3"
Psyco? Yes.
Ubuntu 10.04 Running in VMWare Workstation 7.1.3 Under Windows 7 32-bit
1:42

Once nano is done building you can find it with:

$ find . -name nano

Can you figure out which one is the nano that will run on your Beagle?

Download and Compile the Kernel

The next step is to download and compile the kernel.

We want to keep the kernel source code around so we can experiment with it. Do this:

$ gedit conf/local.conf

Find the line near the top that says INHERIT += " rm_work " and comment it out. This will save the source code.

# INHERIT += " rm_work

Exit gedit and do the following:

$ source ~/.oe/environment-oecore
$ cd ~/BeagleBoard/oe
$ bitbake virtual/kernel

Mine says it has 1032 tasks to do. It took about XX hours to do them. Once done you should get a kernel that will work.

If you accidentally run bitbake without commenting out the above line, after it runs you can comment out the INHERIT line and then run

$ bitbake -c clean virtual/kernel
$ bitbake -f -c compile virtual/kernel

This second run should take less time (one timing: first run took 3.5 hours; the recompiling took 25 minutes).

Download and Compile U-boot

While were' at it, let's get the boot loader we'll be using...

$ bitbake u-boot

I think this took a half hour or so.

Once installed you are ready for kernel work.