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Date: Fri, 18 Nov 2011 12:06:51 -0600
From: Scott Wood <scottwood@freescale.com>
To: Timur Tabi <timur@freescale.com>
Subject: Re: [PATCH 2/2] powerpc/85xx: p1022ds: enable monitor switching via
 pixis indirect mode
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On Fri, Nov 18, 2011 at 11:00:04AM -0600, Timur Tabi wrote:
> Scott Wood wrote:
> >> > How do I update the device tree from platform code?
> 
> > prom_update_property()
> 
> I assume this needs to be called after the DT has been unflattened,
> since it takes a device_node* as a parameter.  Is there any way I can
> modify the tree before it's unflattened?  I'd like to fixup the tree in
> an early_param() function.

What's wrong with doing it in setup_arch()?

Modifying a flat device tree is a more complicated task, and the kernel's
code is read-only.  It's not worth bringing libfdt or similar complexity
in for this, when there are other alternatives.

If it really needs to be done early, consider doing it from U-Boot.  The
bootwrapper would be a decent place as well, but we probably shouldn't
require its use just for this.

-Scott