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Subject: RE: [PATCH 15/16] Add device tree for Ebony
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yoder Stuart-B08248 <stuart.yoder@freescale.com>
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Date: Fri, 16 Feb 2007 08:41:08 +1100
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Cc: linuxppc-dev@ozlabs.org, Heiko Schick <SCHICKHJ@de.ibm.com>,
	Hartmut Penner <HPENNER@de.ibm.com>,
	David Gibson <david@gibson.dropbear.id.au>
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> Is there a DCR binding?  Are the dcr-* properties documented 
> anywhere:
> 
> dcr-reg         // what do these fields mean?
> dcr-parent      // in case there is more than one controller??
> dcr-controller
> dcr-access-method = "native"   // what are the other options?

Yes, we wrote a binding document though I can't find it now. Hartmut or
Heiko, do you have the latest DCR binding document at hand ?

dcr-reg is akin to "reg", it is a list of [dcr numbers, number of dcr]
for a device.

dcr-parent is a phandle to the dcr "controller" or "master" that
generate the DCR cycles

dcr-controller is like "interrupt-controller", it's a property to slap
into any node that is also a dcr-controller. Typically, this can be the
core for a 4xx processor or a separate device for Axon

dcr-access-method can be "native" for 4xx or "mmio" for Axon-type MMIO
mapped DCR bus.

The parent linkage is necessary when using things ike Axon since more
than one Axon can be present in a system, thus more than one MMIO->DCR
"converters" providing each a separate DCR space for controller a
separate set of devices.

Ben