dt-bindings: csky CPU Bindings

This patch adds the documentation to describe that how to add cpu nodes in
dts for SMP.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Rob Herring <robh@kernel.org>

diff --git a/Documentation/devicetree/bindings/csky/cpus.txt b/Documentation/devicetree/bindings/csky/cpus.txt
new file mode 100644 (file)
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+==================
+C-SKY CPU Bindings
+==================
+
+The device tree allows to describe the layout of CPUs in a system through
+the "cpus" node, which in turn contains a number of subnodes (ie "cpu")
+defining properties for every cpu.
+
+Only SMP system need to care about the cpus node and single processor
+needn't define cpus node at all.
+
+=====================================
+cpus and cpu node bindings definition
+=====================================
+
+- cpus node
+
+       Description: Container of cpu nodes
+
+       The node name must be "cpus".
+
+       A cpus node must define the following properties:
+
+       - #address-cells
+               Usage: required
+               Value type: <u32>
+               Definition: must be set to 1
+       - #size-cells
+               Usage: required
+               Value type: <u32>
+               Definition: must be set to 0
+
+- cpu node
+
+       Description: Describes one of SMP cores
+
+       PROPERTIES
+
+       - device_type
+               Usage: required
+               Value type: <string>
+               Definition: must be "cpu"
+       - reg
+               Usage: required
+               Value type: <u32>
+               Definition: CPU index
+       - compatible:
+               Usage: required
+               Value type: <string>
+               Definition: must contain "csky", eg:
+                       "csky,610"
+                       "csky,807"
+                       "csky,810"
+                       "csky,860"
+
+Example:
+--------
+
+       cpus {
+               #address-cells = <1>;
+               #size-cells = <0>;
+               cpu@0 {
+                       device_type = "cpu";
+                       reg = <0>;
+                       status = "ok";
+               };
+
+               cpu@1 {
+                       device_type = "cpu";
+                       reg = <1>;
+                       status = "ok";
+               };
+       };