Difference between revisions of "EBC Exercise 08a Cross-Compiling"
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(→Step 3 - Setting up for the BeagleBoard: Added threads information) |
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== Step 3 - Setting up for the BeagleBoard == | == Step 3 - Setting up for the BeagleBoard == | ||
− | We need a small script to setup the environment, so download | + | We need a small script to setup the environment, so download [http://www.rose-hulman.edu/~yoder/eLinux/files/source-me.txt source-me.txt] to ${OETREE}. |
Now let's setup <code>local.conf</code> for our needs: | Now let's setup <code>local.conf</code> for our needs: | ||
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MACHINE ?= "beagleboard" | MACHINE ?= "beagleboard" | ||
</pre> | </pre> | ||
+ | Also, look at this block of lines: | ||
+ | <pre> | ||
+ | # Make use of SMP and fast disks | ||
+ | PARALLEL_MAKE = "-j4" | ||
+ | BB_NUMBER_THREADS = "4" | ||
+ | </pre> | ||
+ | Here you can tell it how many parallel threads to run. If you have several cores on your machine, make this number big. If you have only one core, you might be better performance setting it to 1. | ||
+ | {{Give | ||
+ | |title=Keep track of you running times and configurations. | ||
+ | |tip=We'll use this data to see what the best settings are. | ||
+ | }} | ||
== Step 4 - Start building == | == Step 4 - Start building == |
Revision as of 10:49, 4 March 2010
This page isn't finished yet, please wait before doing it.
This class is about developing software for embedded Linux. The eLinux site [1] is a good source for embedded Linux in general. There are many on going embedded efforts going on many platforms. Poke around the site a while to get a feel for what's happening.
We are going to use the Ångström Distribution [2]. It's available many platforms. Look around the site, you may recognize some of them.
Instructions for building Ångström are given here [3]; however I'm going to present a Beagle-tuned version of those instructions on this page.
Contents
Step 1 - get Open Embedded metadata
First install git
by running the following on your host computer.
sudo apt-get install git-core
Then run the following to load the meta data.
export OETREE="${HOME}/oe" mkdir -p ${OETREE} && cd ${OETREE} git clone git://git.openembedded.org/openembedded.git openembedded cd openembedded git checkout origin/stable/2009 -b stable/2009
The first git transfers some 336,000 object and takes about 18 minutes with the network running at 600 some KiB/s. Keep an eye on it, mine stopped about 23% in and I had to restart it. The second git takes almost no time.
Now run the following to update the metadata:
cd ${OETREE}/openembedded git pull
You've created a directory called oe
. Go explore around it to see what is there. Be sure to look in oe/openembedded/recipes
. These folders contain instructions on where to get and how to build various things. Look in recipes/Linux
. Here are instructions for building various Linux kernels. We'll be using linux-omap-2.6.*
. What's the highest version you can find?
Step 2 - Installing bitbake and friends
bitbake is the workhorse that knows where to get everything and how to compile it. The following will install bitbake and additional programs that bitbake needs. This may take 5 minutes.
sudo apt-get install bitbake sudo apt-get install g++ sudo apt-get install help2man diffstat texi2html cvs texinfo subversion gawk sudo apt-get autoremove
If you are running Ubuntu you will have to also do the following:
cd /bin sudo mv sh sh.old sudo ln -s bash sh sudo sh -c "echo 0 > /proc/sys/vm/mmap_min_addr"
Finally edit the file /etc/sysctl.conf
using:
sudo gedit /etc/sysctl.conf
Add the following at the end and save.
# This is for bitbake vm.mmap_min_addr = 0
Now you should be ready to run bitbake.
Step 3 - Setting up for the BeagleBoard
We need a small script to setup the environment, so download source-me.txt to ${OETREE}.
Now let's setup local.conf
for our needs:
mkdir -p ${OETREE}/build/conf cp ${OETREE}/openembedded/contrib/angstrom/local.conf ${OETREE}/build/conf/
Open ${OETREE}/build/conf/local.conf
in your favourite editor and add the following to the end of the file.
MACHINE ?= "beagleboard"
Also, look at this block of lines:
# Make use of SMP and fast disks PARALLEL_MAKE = "-j4" BB_NUMBER_THREADS = "4"
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.
Give to the community: Keep track of you running times and configurations. We'll use this data to see what the best settings are. |
Step 4 - Start building
Do the following...
# set environment variables cd ${OETREE} source source-me.txt #Go to the OE tree cd ${OETREE}/openembedded #Make sure it's up to date git pull --rebase #Start building bikebake nano
Give to the community: Psyco JIT compiler bitbake suggest loading a compiler. Load and test the compiler. If it's worth using, write instructions. |
This will take a while. bitbake is installing everything that is needed to compile the system. This includes cross compilers, assemblers, source, everything. I started at 10am and ended around 5:30pm. It was running on just one of the two cores on my laptop. How long did it take on your machine? I notice that an additional 600M of disk space is being used.
Up to this point all we have done is load all the infrastructure needed and compiled the simple nano text editor. We don't even have the kernel yet. Do this to build a basic console image:
bitbake console-image
How did I know to use console-image? I ran the following to find what images were out there:
locate image | grep /oe/
This found every file with image in the name it that also had /oe/ in the path. From this I see that oe/openbmebeed/recipes/images has a bunch of files ending in -image. Take a look at console-image.bb and see what you can figure out.
Step 5 Loading your SD card
Check here for details of where to find the build and what to do with it.