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diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt new file mode 100644 index 0000000000..42f282c2f3 --- /dev/null +++ b/Documentation/devicetree/bindings/numa.txt @@ -0,0 +1,319 @@ +============================================================================== +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-node-id +============================================================================== + +For the purpose of identification, each NUMA node is associated with a unique +token known as a node id. For the purpose of this binding +a node id is a 32-bit integer. + +A device node is associated with a NUMA node by the presence of a +numa-node-id property which contains the node id of the device. + +Example: + /* numa node 0 */ + numa-node-id = <0>; + + /* numa node 1 */ + numa-node-id = <1>; + +============================================================================== +3 - distance-map +============================================================================== + +The optional device tree node distance-map describes the relative +distance (memory latency) between all numa nodes. + +- compatible : Should at least contain "numa-distance-map-v1". + +- distance-matrix + This property defines a matrix to describe the relative distances + between all numa nodes. + It is represented as a list of node pairs and their relative distance. + + Note: + 1. Each entry represents distance from first node to second node. + The distances are equal in either direction. + 2. The distance from a node to self (local distance) is represented + with value 10 and all internode distance should be represented with + a value greater than 10. + 3. distance-matrix should have entries in lexicographical ascending + order of nodes. + 4. There must be only one device node distance-map which must + reside in the root node. + 5. If the distance-map node is not present, a default + distance-matrix is used. + +Example: + 4 nodes connected in mesh/ring topology as below, + + 0_______20______1 + | | + | | + 20 20 + | | + | | + |_______________| + 3 20 2 + + if relative distance for each hop is 20, + then internode distance would be, + 0 -> 1 = 20 + 1 -> 2 = 20 + 2 -> 3 = 20 + 3 -> 0 = 20 + 0 -> 2 = 40 + 1 -> 3 = 40 + + and dt presentation for this distance matrix is, + + distance-map { + compatible = "numa-distance-map-v1"; + distance-matrix = <0 0 10>, + <0 1 20>, + <0 2 40>, + <0 3 20>, + <1 0 20>, + <1 1 10>, + <1 2 20>, + <1 3 40>, + <2 0 40>, + <2 1 20>, + <2 2 10>, + <2 3 20>, + <3 0 20>, + <3 1 40>, + <3 2 20>, + <3 3 10>; + }; + +============================================================================== +4 - Empty memory nodes +============================================================================== + +Empty memory nodes, which no memory resides in, are allowed. There are no +device nodes for these empty memory nodes. However, the NUMA node IDs and +distance maps are still valid and memory may be added into them through +hotplug afterwards. + +Example: + + memory@0 { + device_type = "memory"; + reg = <0x0 0x0 0x0 0x80000000>; + numa-node-id = <0>; + }; + + memory@80000000 { + device_type = "memory"; + reg = <0x0 0x80000000 0x0 0x80000000>; + numa-node-id = <1>; + }; + + /* Empty memory node 2 and 3 */ + distance-map { + compatible = "numa-distance-map-v1"; + distance-matrix = <0 0 10>, + <0 1 20>, + <0 2 40>, + <0 3 20>, + <1 0 20>, + <1 1 10>, + <1 2 20>, + <1 3 40>, + <2 0 40>, + <2 1 20>, + <2 2 10>, + <2 3 20>, + <3 0 20>, + <3 1 40>, + <3 2 20>, + <3 3 10>; + }; + +============================================================================== +5 - Example dts +============================================================================== + +Dual socket system consists of 2 boards connected through ccn bus and +each board having one socket/soc of 8 cpus, memory and pci bus. + + memory@c00000 { + device_type = "memory"; + reg = <0x0 0xc00000 0x0 0x80000000>; + /* node 0 */ + numa-node-id = <0>; + }; + + memory@10000000000 { + device_type = "memory"; + reg = <0x100 0x0 0x0 0x80000000>; + /* node 1 */ + numa-node-id = <1>; + }; + + cpus { + #address-cells = <2>; + #size-cells = <0>; + + cpu@0 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x0>; + enable-method = "psci"; + /* node 0 */ + numa-node-id = <0>; + }; + cpu@1 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x1>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@2 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x2>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@3 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x3>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@4 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x4>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@5 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x5>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@6 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x6>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@7 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x7>; + enable-method = "psci"; + numa-node-id = <0>; + }; + cpu@8 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x8>; + enable-method = "psci"; + /* node 1 */ + numa-node-id = <1>; + }; + cpu@9 { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0x9>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@a { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xa>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@b { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xb>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@c { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xc>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@d { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xd>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@e { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xe>; + enable-method = "psci"; + numa-node-id = <1>; + }; + cpu@f { + device_type = "cpu"; + compatible = "arm,armv8"; + reg = <0x0 0xf>; + enable-method = "psci"; + numa-node-id = <1>; + }; + }; + + pcie0: pcie0@848000000000 { + compatible = "arm,armv8"; + device_type = "pci"; + bus-range = <0 255>; + #size-cells = <2>; + #address-cells = <3>; + reg = <0x8480 0x00000000 0 0x10000000>; /* Configuration space */ + ranges = <0x03000000 0x8010 0x00000000 0x8010 0x00000000 0x70 0x00000000>; + /* node 0 */ + numa-node-id = <0>; + }; + + pcie1: pcie1@948000000000 { + compatible = "arm,armv8"; + device_type = "pci"; + bus-range = <0 255>; + #size-cells = <2>; + #address-cells = <3>; + reg = <0x9480 0x00000000 0 0x10000000>; /* Configuration space */ + ranges = <0x03000000 0x9010 0x00000000 0x9010 0x00000000 0x70 0x00000000>; + /* node 1 */ + numa-node-id = <1>; + }; + + distance-map { + compatible = "numa-distance-map-v1"; + distance-matrix = <0 0 10>, + <0 1 20>, + <1 1 10>; + }; |