Difference between revisions of "EBC Exercise 25 Configuring U-boot"

Revision as of 20:17, 28 March 2010

This follows the approach taken in ECE597 Configuring the Kernel. We'll use bitbake to get the source files for U-boot and then we'll edit them.

bitbake

When you did ECE597 Installing The Ångström Distribution you used bitbake to build console-image. During that build the kernel was downloaded and compiled. If you used the default configure, the source code was removed once it was done. Check and see:

$ cd ${OETREE}/angstrom-dev/work/beagleboard-angstrom-linux-gnueabi
$ ls

You should see a directory starting with u-boot-. The rest of the name tells what version you have. Change to that directory and see what's there:

$ cd u-boot-*
$ ls

If you see a git directory, you are in luck. If you see just a temp directory you need to do the following to reload the sources:

$ cd ${OETREE}/build/conf
$ gedit local.conf

Find the line near the top that says INHERIT += " rm_work " and comment it out.

# INHERIT += " rm_work "

Save the file and then:

 cd ${OETREE}/openembedded
$ bitbake -c clean u-boot
$ bitbake -f -c compile u-boot

• The first bitbake command tells bitbake to remove the previously made binary file for that package (think "make clean"), which will force it to re-do what it previously did with the console-image build.
• The second bitbake line forces bitbake to rebuild the u-boot package, which will require re-extracting the previously deleted source code, and apply the relevant OE related patches.

This took 4 minutes on my machine.

Once done go back to

$ cd ${OETREE}/angstrom-dev/work/beagleboard-angstrom-linux-gnueabi/u-boot-*
$ ls

You should now see the git directory. cd to it and look around.

Compiling U-boot

You can now compile U-boot. Make the following file called source-me.txt.

export OETREE="${HOME}/oe"
export ARCH=arm
export CROSS_COMPILE=arm-angstrom-linux-gnueabi-

PATH=${OETREE}/angstrom-dev/staging/i686-linux/usr/bin/:${PATH}
PATH=${OETREE}/angstrom-dev/cross/armv7a/bin/:${PATH}

Save the file and enter:

$ source source-me.txt

Now a simple make should compile U-boot.

Assignment: Modify u-boot to include your initials in the prompt.

Hint: Look for the omap3_beagle.h file.