From mboxrd@z Thu Jan  1 00:00:00 1970
From: Segher Boessenkool <segher-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH 0/3] GIC OF bindings
Date: Wed, 21 Sep 2011 07:16:52 +0200
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To: David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>
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> Just out of curiosity where does this "interrupt-parent" property
> come from?
>
> On platforms I am familiar with, the parent path is walked to the root
> and we stop at device nodes that have "interrupt-map" and
> "interrupt-map-mask" properties.

"interrupt-parent" is defined in the Open Firmware "interrupt mapping"
recommended practice, the same place as "interrupt-map" etc. are.

> The mechanism shown here seems overly simplistic and not able to  
> handle
> the cases handled by existing OF property schemes in use for several
> years on real systems.

"interrupt-parent" is only meant to be used for the simple cases.  It's
quite handy there.  It is also required in all "interrupt-controller"
nodes that aren't the root of the interrupt tree.


Segher