Subject: Re: Could the DTS experts look at this?

From: Arnd Bergmann <[email-masked]>
Date: Tue, 12 Feb 2008 01:21:44 +0100

On Tuesday 12 February 2008, David Gibson wrote:
> Or to expand. =A0It's relatively easy now to just include multiple nodes
> in the tree and either delete or nop some of them out conditionally
> using libfdt. =A0But the conditional logic should be in the manipulating
> agent (u-boot or bootwrapper or whatever), there's no way we're going
> to require a conditional expression parser to interpret the device
> tree blob itself.

How about making the logic to nop out nodes a little more generic
without changes to the binary format?
E.g. you could have a "linux,conditional-node" property in the device
tree whose value is compared to a HW configuration specific string.
In Sean's example, you can have linux,conditional-node=3D"Rev.A" in
some nodes and linux,conditional-node=3D"Rev.B" in others, then
knock out all devices that have a non-matching linux,conditional-node
property, and finally remove the properties themselves before starting
the kernel.

	Arnd <><