Panda How to kernel 2 6 38

-Kernel building for kernel 2.6.38.

Newer kernels require that you use a more recent MLO (x-loader) and u-boot than described in previous How-To's.

You can build these from source, or try to find binaries. One issue with the binary route is that you might want to alter the kernel command line embedded inside u-boot. Such as for experimenting with different partition formats, or different filesystem types (ext3 vs ext2), etc. Of course you could stop the autoboot and type it in yourself, but we will build from source.

For this How-to, we will use the Code Sourcery G++ version arm-2009q3. It should already be installed on your system. Kernels have also been successfully built with arm-2010q1.

First, let's get the x-loader source code and build it.

git clone git://gitorious.org/x-loader/x-loader.git

cd to the x-loader directory

Then using git or gitk make and check out a new branch at the commit "6f3a261 omap1: remove support for 1710 and 1510"

Next, select the panda config:

make CROSS_COMPILE=Path_to_your/arm-2009q3/bin/arm-none-linux-gnueabi- omap4430panda_config

Now compile MLO:

make CROSS_COMPILE=Path_to_your/arm-2009q3/bin/arm-none-linux-gnueabi- ift

This should produce the MLO file in the x-loader directory.

Now for U-boot:

git clone git://git.denx.de/u-boot.git

cd to the u-boot directory

Then using git or gitk make and check out a new branch at tag: v2010.12

Next, select the panda config:

make CROSS_COMPILE=Path_to_your/arm-2009q3/bin/arm-none-linux-gnueabi- omap4_panda_config

Change ttyS2 to ttyO2 in the u-boot kernel command line in: u-boot/include/configs/omap4_panda.h

Now compile U-boot:

make USE_PRIVATE_LIBGG=yes CROSS_COMPILE=Path_to_your/arm-2009q3/bin/arm-none-linux-gnueabi-

This should produce u-boot.bin in the u-boot directory

Now for the kernel:

Either download http://www.kernel.org/pub/linux/kernel/v2.6/testing/linux-2.6.38.tar.bz2

or

git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git

-Warning- this will be a really big download

cd to the appropriate root directory

If you downloaded the .tar.bz2 file you can skip this step.

Using git or gitk make and check out a new branch at tag: v2.6.38

Next, select the panda config:

make ARCH=arm omap2plus_defconfig

Dave Anders figured out what the problem that some users had been seeing with an over current condition shutting the board down. He has produced a patch that appears to resolve this issue. Here is his description:

"The pandaboard does not use the VUSIM or VAUX1 power regulators on the TWL6030 and are left floating. if the VUSIM and VAUX1 power regulators are initilized, noise on the unloaded regulators generates an overcurrent interrupt causing the system to power down. this patch removes the initialization of the unused power regulators of VUSIM and VAUX1."

This patch can be applied to 2.6.37 and the 2.6.38-rcx series with a bit of fuzz and maybe a few lines of offset, as well as 2.6.38.

Get a copy of the patch [[Media:dave_reg.patch|dave_reg.patch]]

Apply it

patch -p1 < dave_reg.patch

It should apply to the vanilla sources without problems.

Now compile the kernel:

make -j10 V=99 ARCH=arm CROSS_COMPILE=Path_to_your/arm-2009q3/bin/arm-none-linux-gnueabi- uImage

In these newer kernels the ttyOx serial ports are given dynamic major minor node numbers, it is important to have your rootfs use udev or mdev to figure out which ones they are.

Put the MLO, uboot.bin and uImage on your vfat partion of your SD card, insert into your trusty pandaboard and power it up. Depending on your rootfs and whether your udev/mdev is setup and working, the kernel should boot. udev/mdev problems will occur when init tries to run inittab.

Once you have the kernel booting, go back and

make ARCH=arm menuconfig

and turn on the usb networking, EHCI and whatever else you might want to play with, then rebuild the kernel.

Or, just use this config [[Media:config.2.6.38|config.2.6.38]] as it has only the changes needed for the pandaboard's usb networking and EHCI.

-Note- Remember to run make ARCH=arm oldconfig to update things that were changed in the new release.

USB and ethernet work, but hdmi video does not as of 3/15/2011.

Here is what should come out the serial port during bootup: http://pastebin.com/jYRs95MH

Of course that is my rootfs, which was built here: http://elinux.org/Panda_How_to_buildroot

With the sysinit part of inittab looking like this:

::sysinit:/bin/mount -o remount,rw / ::sysinit:/bin/mount -t tmpfs -o size=64k,mode=0755 tmpfs /dev ::sysinit:/bin/mkdir /dev/pts ::sysinit:/bin/mount -t devpts devpts /dev/pts ::sysinit:/bin/mknod -m 660 /dev/console c 5 1 ::sysinit:/bin/mknod -m 660 /dev/null c 1 3 ::sysinit:/bin/mount -t sysfs sysfs /sys null::sysinit:/bin/echo /sbin/mdev > /proc/sys/kernel/hotplug null::sysinit:/sbin/mdev -s null::sysinit:/bin/mount -a null::sysinit:/bin/hostname -F /etc/hostname ::sysinit:/etc/init.d/rcS
 * 1) Startup the system
 * 1) now run any rc scripts