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authorGanapatrao Kulkarni <gkulkarni@caviumnetworks.com>2016-04-08 15:50:24 -0700
committerGraeme Gregory <graeme.gregory@linaro.org>2016-05-17 12:03:36 +0100
commite10c5dce05982e386b8998cc7065c8b01c4248f1 (patch)
treecd48e386c02954b93413e1572c8cc22127f9bbaa /Documentation
parentdd89c004e2b70e97eef19886e74a0c4464302b78 (diff)
downloadleg-kernel-e10c5dce05982e386b8998cc7065c8b01c4248f1.tar.gz
Documentation, dt, numa: dt bindings for NUMA.
Add DT bindings for numa mapping of memory, CPUs and IOs. Reviewed-by: Robert Richter <rrichter@cavium.com> Signed-off-by: Ganapatrao Kulkarni <gkulkarni@caviumnetworks.com> Signed-off-by: David Daney <david.daney@cavium.com> Acked-by: Rob Herring <robh@kernel.org>
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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-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 - 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>;
+ };