[PATCH 1/2] powerpc: document the MPIC device tree binding
B08248 at freescale.com
Wed Jan 19 07:21:33 EST 2011
> From: Meador Inge <meador_inge at mentor.com>
> Date: Mon, Jan 17, 2011 at 6:52 PM
> Subject: [PATCH 1/2] powerpc: document the MPIC device tree binding
> To: linuxppc-dev at lists.ozlabs.org
> Cc: minge <meador_inge at mentor.com>,
> devicetree-discuss at lists.ozlabs.org, "Blanchard, Hollis"
> <Hollis_Blanchard at mentor.com>
> This binding documents several properties that have been in use for quite
> some time, and adds one new property 'no-reset', which controls whether the
> MPIC should be reset during runtime initialization.
> Signed-off-by: Meador Inge <meador_inge at mentor.com>
> CC: Hollis Blanchard <hollis_blanchard at mentor.com>
> 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.
> 1 files changed, 78 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/powerpc/dts-bindings/mpic.txt
> diff --git a/Documentation/powerpc/dts-bindings/mpic.txt
> new file mode 100644
> index 0000000..3a67919
> --- /dev/null
> +++ b/Documentation/powerpc/dts-bindings/mpic.txt
> @@ -0,0 +1,78 @@
> +* MPIC Binding
> +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  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.
The proposed new properties really should go back into the ePAPR.
> +** Required properties:
> + NOTE: Many of these descriptions were paraphrased from  to aid
> + readability.
> + - name : Specifies the name of the MPIC.
Drop this. No DTS files use it.
> + - 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
> + - 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.
> + - interrupt-controller : The presence of this property identifies
> + the node
> + as a MPIC. No property value should be
> + - #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?
> +** 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.
More information about the Linuxppc-dev