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_i...@mentor.com>
CC: Hollis Blanchard <hollis_blanch...@mentor.com>
---
Documentation/powerpc/dts-bindings/mpic.txt | 78
+++++++++++++++++++++++++++
1 files changed, 78 insertions(+), 0 deletions(-)
create mode 100644 Documentation/powerpc/dts-bindings/mpic.txt
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b/Documentation/powerpc/dts-bindings/mpic.txt
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+* 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 [1] and is a
superset
+of that binding.
+
+** Required properties:
+
+ NOTE: Many of these descriptions were paraphrased from [1] to aid
+ readability.
+
+ - name : Specifies the name of the MPIC.
+ - device_type : Specifies the device type of this MPIC. The value
of this
+ property shall be "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".
+ - 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.
+
+** 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.
+
+** Example:
+
+ mpic: pic@40000 {
+ // This is an interrupt controller node.
+ interrupt-controller;
+
+ // No address cells so that 'interrupt-map' nodes which reference
+ // this MPIC node do not need a parent address specifier.
+ #address-cells = <0>;
+
+ // Two cell to encode interrupt sources.
+ #interrupt-cells = <2>;
+
+ // Offset address of 0x40000 and size of 0x40000.
+ reg = <0x40000 0x40000>;
+
+ // Compatible with Open PIC.
+ compatible = "chrp,open-pic";
+
+ // An Open PIC device.
+ device_type = "open-pic";
+
+ // The sources 0xb1 and 0xb2 are off limits for use and should
not be
+ // initialized by the OS.
+ protected-sources = <0xb1 0xb2>;
+
+ // The MPIC should not be reset.
+ no-reset;
+ };
+
+* References
+
+[1] PowerPC Microprocessor Common Hardware Reference Platform (CHRP)
Binding,
+ Version 1.8, 1998. Published by the Open Firmware Working Group.
+ (http://playground.sun.com/1275/bindings/chrp/chrp1_8a.ps)
+[2] Open Firmware Recommended Practice: Interrupt Mapping, Version 0.9.
1996.
+ Published by the Open Firmware Working Group.
+ (http://playground.sun.com/1275/practice/imap/imap0_9d.pdf)
+
-- 1.6.3.3
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