Re: [PATCH 0/3] patches to allow DTB to be appended to the ARM zImage

On Sun, Jun 12, 2011 at 10:21:31AM +0100, Russell King - ARM Linux wrote:

On Sun, Jun 12, 2011 at 04:34:15PM +0800, Shawn Guo wrote:

quoted

On Sun, Jun 12, 2011 at 09:15:41AM +0100, Russell King - ARM Linux wrote:

quoted

On Sun, Jun 12, 2011 at 02:06:37AM -0400, Nicolas Pitre wrote:

quoted

This is a resend of those patches with fixups after the latest changes
in mainline.

[PATCH 1/3] ARM: zImage: ensure it is always a multiple of 64 bits in size
This one is new and trivial.

[PATCH 2/3] ARM: zImage: Allow the appending of a device tree binary
Mostly John Bonesio's version with some adjustments and cleanups.

[PATCH 3/3] ARM: zImage: make sure appended DTB doesn't get overwritten by kernel .bss
New, simpler alternative to Tony Lindgren's version.

One thing which has been bugging me for some time is that the DT stuff
completely overrides the ATAGs.  This is wrong with solutions like this.

We have a set of perfectly good boot loaders which provide correct
information to the kernel via ATAGs.  If we start moving everything
over to DT, then we run into a problem because the ATAGs are ignored -
stuff such as the RAM size and command line passed from the boot loader
will be entirely ignored, instead these having to be encoded into the
kernel at build time.

What u-boot does right now is replacing the parameters in dtb with
its for those it's interested in, for example command line is one,
before it passes dtb to kernel.

What if your platform doesn't use uboot?

Add dtb parsing support with the help from libfdt, I guess.  It is
some amount of work, but it's not a rewrite of bootloader, IMHO.

-- 
Regards,
Shawn