Re: [PATCH 0/3] GIC OF bindings

From: Segher Boessenkool
Date: Wed Sep 21 2011 - 01:19:09 EST


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

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