On 01/18/2011 02:21 PM, Yoder Stuart-B08248 wrote:
Documentation/powerpc/dts-bindings/mpic.txt | 78
This is really the binding for an open-pic interrupt controller
and I think the name should reflect that-- open-pic.txt.
Yup, agreed.
+This binding specifies what properties and child nodes must be
+available on the device tree representation of the "MPIC" interrupt
+controller. This binding is based on the binding defined for Open PIC
+in [1] and is a superset of that binding.
I think it would be better to base this on the ePAPR binding which
was based on the original chrp binding. Properties like "name"
and "device_type" are deprecated not being used in flat device trees.
<http://www.power.org/resources/downloads/Power_ePAPR_APPROVED_v1.0.pdf>
The proposed new properties really should go back into the ePAPR.
I read portions of ePAPR while writing this binding and considered that.
My only worry was that ePAPR is focused on embedded systems and this
binding will have to cover non-embedded systems that exist in the
kernel. However, perhaps that is not a legitimate concern?
+
+** Required properties:
+
+ NOTE: Many of these descriptions were paraphrased from [1] to aid
+ readability.
+
+ - name : Specifies the name of the MPIC.
Drop this. No DTS files use it.
Done.
+ - device_type : Specifies the device type of this MPIC. The value
+ of this
+ property shall be "open-pic".
device_type is deprecated, since this is not real open-firmware. In
practice the kernel is matching on device_type, but we want to move
away from that to match on "compatible", just hasn't been implemented
yet.
I will drop this property with the expectation that the kernel will be
fixed. From a quick grep of '.../arch/powerpc' it looks like most uses
are of the form:
np = of_find_node_by_type(NULL, "open-pic");
if (np == NULL)
return;
In most of these cases I suppose the 'of_find_node_by_type' calls could
just be replaced with calls to 'of_find_compatible_node(NULL, "open-pic")'.
+ - reg : Specifies the base physical address(s) and size(s) of this
+ MPIC's
+ addressable register space.
+ - compatible : Specifies the compatibility list for the MPIC. The
+ property
+ value shall include "chrp,open-pic".
In the ePAPR we modified this to just "open-pic", because this has
nothing to do with chrp anymore. I think just "open-pic" is
what we want.
OK, but as a migration path we should allow the kernel to accept both
(Scott mentioned this in another reply), but "open-pic" is the
documented correct way.
+ - interrupt-controller : The presence of this property identifies
+ the node
+ as a MPIC. No property value should be
defined.
+ - #address-cells : Specifies the number of cells needed to encode an
+ address. The value of this property shall always
+ be 0
+ so that 'interrupt-map' nodes do not have to
+ specify a
+ parent unit address.
+ - #interrupt-cells : Specifies the number of cells needed to encode
+ an
+ interrupt source.
Should be 2, correct?
Yup.
+** Optional properties:
+
+ - no-reset : The presence of this property indicates that the MPIC
+ should not be reset during runtime initialization.
+ - protected-sources : Specifies a list of interrupt sources that are
+ not
+ available for use and whose corresponding
+ vectors
+ should not be initialized. A typical use case
+ for
+ this property is in AMP systems where multiple
+ independent operating systems need to share
+ the MPIC
+ without clobbering each other.
I do think you need to include the definition of interrupt
specifiers here. Feel free to cut/paste text from my
Freescale mpic binding.
OK, I will look into that. Thanks.
--
Meador Inge | meador_inge AT mentor.com
Mentor Embedded | http://www.mentor.com/embedded-software
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