[RFC PATCH v2 2/4] Documentation: arm64/arm: dt bindings for numa.

[Ganapatrao Kulkarni]

DT bindings for numa map for memory, cores to node and
proximity distance matrix of nodes to each other.

Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni at caviumnetworks.com>
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 Documentation/devicetree/bindings/arm/numa.txt | 103 +++++++++++++++++++++++++
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+==============================================================================
+NUMA binding description.
+==============================================================================
+
+==============================================================================
+1 - Introduction
+==============================================================================
+
+Systems employing a Non Uniform Memory Access (NUMA) architecture contain
+collections of hardware resources including processors, memory, and I/O buses,
+that comprise what is commonly known as a “NUMA node”. Processor
+accesses to memory within the local NUMA node is
+generally faster than processor accesses to memory outside of the local
+NUMA node. DT defines interfaces that allow the platform to convey NUMA node
+topology information to OS.
+
+==============================================================================
+2 - numa-map node
+==============================================================================
+
+DT Binding for NUMA can be defined for memory and CPUs to map them to
+respective NUMA nodes.
+
+The DT binding can defined using numa-map node.
+The numa-map will have following properties to define NUMA topology.
+
+- mem-map:	This property defines the association between a range of
+		memory and the proximity domain/numa node to which it belongs.
+
+note: memory range address is passed using either memory node of
+DT or UEFI system table and should match to the address defined in mem-map.
+
+- cpu-map:	This property defines the association of range of processors
+		(range of cpu ids) and the proximity domain to which
+		the processor belongs.
+
+- node-matrix:	This table provides a matrix that describes the relative
+		distance (memory latency) between all System Localities.
+		The value of each Entry[i j distance] in node-matrix table,
+		where i represents a row of a matrix and j represents a
+		column of a matrix, indicates the relative distances
+		from Proximity Domain/Numa node i to every other
+		node j in the system (including itself).
+
+The numa-map node must contain the appropriate #address-cells,
+#size-cells and #node-count properties.
+
+
+==============================================================================
+4 - Example dts
+==============================================================================
+
+Example 1: 2 Node system each having 8 CPUs and a Memory.
+
+	numa-map {
+		#address-cells = <2>;
+		#size-cells = <1>;
+		#node-count = <2>;
+		mem-map =  <0x0 0x00000000 0>,
+		           <0x100 0x00000000 1>;
+
+		cpu-map = <0 7 0>,
+			  <8 15 1>;
+
+		node-matrix = <0 0 10>,
+			      <0 1 20>,
+			      <1 0 20>,
+			      <1 1 10>;
+	};
+
+Example 2: 4 Node system each having 4 CPUs and a Memory.
+
+	numa-map {
+		#address-cells = <2>;
+		#size-cells = <1>;
+		#node-count = <2>;
+		mem-map =  <0x0 0x00000000 0>,
+		           <0x100 0x00000000 1>,
+		           <0x200 0x00000000 2>,
+		           <0x300 0x00000000 3>;
+
+		cpu-map = <0 7 0>,
+			  <8 15 1>,
+			  <16 23 2>,
+			  <24 31 3>;
+
+		node-matrix = <0 0 10>,
+			      <0 1 20>,
+			      <0 2 20>,
+			      <0 3 20>,
+			      <1 0 20>,
+			      <1 1 10>,
+			      <1 2 20>,
+			      <1 3 20>,
+			      <2 0 20>,
+			      <2 1 20>,
+			      <2 2 10>,
+			      <2 3 20>,
+			      <3 0 20>,
+			      <3 1 20>,
+			      <3 2 20>,
+			      <3 3 10>;
+	};
-- 
1.8.1.4