Re: [PATCH 2/4] ARM:boot:device tree: Merge specific atags into the device tree

On Mon, Feb 28, 2011 at 11:45 PM, Nicolas Pitre [off-list ref] wrote:

On Mon, 28 Feb 2011, John Bonesio wrote:

quoted

This patch is to merge in key atags into the appended device tree.  An appended
device tree is where the zImage has a dtb binary appended at the end of it. The
boot code looks for an appended device tree, then looks for a few key atags
passed in by the bootloader.

The bootargs and memory size settings, if they exist, override existing values
in the appended device tree. If these values don't currently exist in the
appended device tree, they are added.

Signed-off-by: John Bonesio <bones-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>

Is this really useful?

I understand this might be handy for testing purposes.  But if your
bootloader does ATAG only then your hardware is likely to have support
in the kernel without device tree support just fine.

IOW I don't think this would be of much value in upstream.

That's fine.  This feature was implemented to meet a client's
requirement and to experiment with manipulating the .dtb in the zimage
wrapper.  We're posting it here for completeness if anyone else wants
to play with it.  Same for the last patch that allows appending
multiple dtbs.

g.