[PATCH v2] Documentation: DT: arm: Add topology property to define package boundaries
Lorenzo Pieralisi
lorenzo.pieralisi at arm.com
Fri Feb 9 04:00:34 PST 2018
The current ARM DT topology description provides the operating system
with a topological view of the system that is based on leaf nodes
representing either cores or threads (in an SMT system) and a
hierarchical set of cluster nodes that creates a hierarchical topology
view of how those cores and threads are grouped.
As opposed to the ACPI topology description ([1], PPTT table), this
hierarchical representation of clusters does not allow to describe what
topology level actually represents the physical package boundary, which
is a key piece of information to be used by an operating system to
optimize resource allocation and scheduling.
Define an optional, backward compatible boolean property for cluster
nodes that, by reusing the ACPI nomenclature, add to the ARM DT
topological description a binding to define what cluster level
represents a physical package boundary.
[1] http://www.uefi.org/sites/default/files/resources/ACPI_6_2.pdf
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi at arm.com>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Sudeep Holla <sudeep.holla at arm.com>
Cc: Jeremy Linton <jeremy.linton at arm.com>
Cc: Morten Rasmussen <morten.rasmussen at arm.com>
Cc: Frank Rowand <frowand.list at gmail.com>
Cc: Mark Rutland <mark.rutland at arm.com>
---
v1->v2:
- Added dual-package example
- Improved physical-package property description according to review
- Dropped RFC tag
v1: https://marc.info/?l=linux-arm-kernel&m=151664137216555&w=2
Documentation/devicetree/bindings/arm/topology.txt | 432 +++++++++++++++++++++
1 file changed, 432 insertions(+)
diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/arm/topology.txt
index de9eb0486630..09b3b22e57c1 100644
--- a/Documentation/devicetree/bindings/arm/topology.txt
+++ b/Documentation/devicetree/bindings/arm/topology.txt
@@ -109,6 +109,21 @@ Bindings for cluster/cpu/thread nodes are defined as follows:
The cluster node name must be "clusterN" as described in 2.1 above.
A cluster node can not be a leaf node.
+ Properties for cluster nodes:
+
+ - physical-package
+ Usage: optional
+ Value type: <empty>
+ Definition: if present the cluster node represents the
+ boundary of a physical package, whether socketed
+ or surface mounted.
+ The cluster node itself and all its children nodes
+ represent a single distinct physical-package unit.
+ The cluster node parent and sibling cluster nodes
+ (if any) must therefore be considered part of
+ separate physical package units in multi
+ physical-package systems.
+
A cluster node's child nodes must be:
- one or more cluster nodes; or
@@ -470,6 +485,423 @@ cpus {
};
};
+Example 3 (ARM 64-bit, 32-cpu system, 2 packages):
+
+cpus {
+ #size-cells = <0>;
+ #address-cells = <2>;
+
+ cpu-map {
+ cluster0 {
+ physical-package;
+
+ cluster0 {
+ core0 {
+ cpu = <&CPU0>;
+ };
+
+ core1 {
+ cpu = <&CPU1>;
+ };
+
+ core2 {
+ cpu = <&CPU2>;
+ };
+
+ core3 {
+ cpu = <&CPU3>;
+ };
+ };
+
+ cluster1 {
+ core0 {
+ cpu = <&CPU4>;
+ };
+
+ core1 {
+ cpu = <&CPU5>;
+ };
+
+ core2 {
+ cpu = <&CPU6>;
+ };
+
+ core3 {
+ cpu = <&CPU7>;
+ };
+ };
+
+ cluster2 {
+ core0 {
+ cpu = <&CPU8>;
+ };
+
+ core1 {
+ cpu = <&CPU9>;
+ };
+
+ core2 {
+ cpu = <&CPU10>;
+ };
+
+ core3 {
+ cpu = <&CPU11>;
+ };
+ };
+
+ cluster3 {
+ core0 {
+ cpu = <&CPU12>;
+ };
+
+ core1 {
+ cpu = <&CPU13>;
+ };
+
+ core2 {
+ cpu = <&CPU14>;
+ };
+
+ core3 {
+ cpu = <&CPU15>;
+ };
+ };
+ };
+
+ cluster1 {
+ physical-package;
+
+ cluster0 {
+ core0 {
+ cpu = <&CPU16>;
+ };
+
+ core1 {
+ cpu = <&CPU17>;
+ };
+
+ core2 {
+ cpu = <&CPU18>;
+ };
+
+ core3 {
+ cpu = <&CPU19>;
+ };
+ };
+
+ cluster1 {
+ core0 {
+ cpu = <&CPU20>;
+ };
+
+ core1 {
+ cpu = <&CPU21>;
+ };
+
+ core2 {
+ cpu = <&CPU22>;
+ };
+
+ core3 {
+ cpu = <&CPU23>;
+ };
+ };
+
+ cluster2 {
+ core0 {
+ cpu = <&CPU24>;
+ };
+
+ core1 {
+ cpu = <&CPU25>;
+ };
+
+ core2 {
+ cpu = <&CPU26>;
+ };
+
+ core3 {
+ cpu = <&CPU27>;
+ };
+ };
+
+ cluster3 {
+ core0 {
+ cpu = <&CPU28>;
+ };
+
+ core1 {
+ cpu = <&CPU29>;
+ };
+
+ core2 {
+ cpu = <&CPU30>;
+ };
+
+ core3 {
+ cpu = <&CPU31>;
+ };
+ };
+ };
+ };
+
+ CPU0: cpu at 0 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x0>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU1: cpu at 1 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x1>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU2: cpu at 2 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x2>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU3: cpu at 3 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x3>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU4: cpu at 100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU5: cpu at 101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU6: cpu at 102 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x102>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU7: cpu at 103 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x103>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU8: cpu at 200 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00200>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU9: cpu at 201 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00201>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU10: cpu at 202 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00202>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU11: cpu at 203 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00203>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU12: cpu at 300 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00300>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU13: cpu at 301 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00301>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU14: cpu at 302 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00302>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU15: cpu at 303 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x00303>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU16: cpu at 10000 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10000>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU17: cpu at 10001 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10001>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU18: cpu at 10002 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10002>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU19: cpu at 10003 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10003>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU20: cpu at 10100 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10100>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU21: cpu at 10101 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10101>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU22: cpu at 10102 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10102>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU23: cpu at 10103 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10103>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU24: cpu at 10200 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10200>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU25: cpu at 10201 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10201>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU26: cpu at 10202 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10202>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU27: cpu at 10203 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10203>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU28: cpu at 10300 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10300>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU29: cpu at 10301 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10301>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU30: cpu at 10302 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10302>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+
+ CPU31: cpu at 10303 {
+ device_type = "cpu";
+ compatible = "arm,cortex-a72";
+ reg = <0x0 0x10303>;
+ enable-method = "spin-table";
+ cpu-release-addr = <0 0x20000000>;
+ };
+};
+
===============================================================================
[1] ARM Linux kernel documentation
Documentation/devicetree/bindings/arm/cpus.txt
--
2.15.0
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