From 1bd524f7e8d8f194cd94bc4535df91391d0f1dc8 Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Thu, 10 Feb 2022 11:19:46 +0530 Subject: [PATCH] dt-bindings: Add common bindings for ARM and RISC-V idle states The RISC-V CPU idle states will be described in under the /cpus/idle-states DT node in the same way as ARM CPU idle states. This patch adds common bindings documentation for both ARM and RISC-V idle states. Signed-off-by: Anup Patel Signed-off-by: Anup Patel Reviewed-by: Rob Herring Reviewed-by: Guo Ren Signed-off-by: Palmer Dabbelt --- .../bindings/arm/msm/qcom,idle-state.txt | 2 +- Documentation/devicetree/bindings/arm/psci.yaml | 2 +- .../bindings/{arm => cpu}/idle-states.yaml | 228 +++++++++++++++++++-- Documentation/devicetree/bindings/riscv/cpus.yaml | 6 + 4 files changed, 219 insertions(+), 19 deletions(-) rename Documentation/devicetree/bindings/{arm => cpu}/idle-states.yaml (74%) diff --git a/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt index 6ce0b21..606b4b1 100644 --- a/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt +++ b/Documentation/devicetree/bindings/arm/msm/qcom,idle-state.txt @@ -81,4 +81,4 @@ Example: }; }; -[1]. Documentation/devicetree/bindings/arm/idle-states.yaml +[1]. Documentation/devicetree/bindings/cpu/idle-states.yaml diff --git a/Documentation/devicetree/bindings/arm/psci.yaml b/Documentation/devicetree/bindings/arm/psci.yaml index 8b77cf8..dd83ef2 100644 --- a/Documentation/devicetree/bindings/arm/psci.yaml +++ b/Documentation/devicetree/bindings/arm/psci.yaml @@ -101,7 +101,7 @@ properties: bindings in [1]) must specify this property. [1] Kernel documentation - ARM idle states bindings - Documentation/devicetree/bindings/arm/idle-states.yaml + Documentation/devicetree/bindings/cpu/idle-states.yaml patternProperties: "^power-domain-": diff --git a/Documentation/devicetree/bindings/arm/idle-states.yaml b/Documentation/devicetree/bindings/cpu/idle-states.yaml similarity index 74% rename from Documentation/devicetree/bindings/arm/idle-states.yaml rename to Documentation/devicetree/bindings/cpu/idle-states.yaml index 52bce5d..95506ff 100644 --- a/Documentation/devicetree/bindings/arm/idle-states.yaml +++ b/Documentation/devicetree/bindings/cpu/idle-states.yaml @@ -1,25 +1,30 @@ # SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2 --- -$id: http://devicetree.org/schemas/arm/idle-states.yaml# +$id: http://devicetree.org/schemas/cpu/idle-states.yaml# $schema: http://devicetree.org/meta-schemas/core.yaml# -title: ARM idle states binding description +title: Idle states binding description maintainers: - Lorenzo Pieralisi + - Anup Patel description: |+ ========================================== 1 - Introduction ========================================== - ARM systems contain HW capable of managing power consumption dynamically, - where cores can be put in different low-power states (ranging from simple wfi - to power gating) according to OS PM policies. The CPU states representing the - range of dynamic idle states that a processor can enter at run-time, can be - specified through device tree bindings representing the parameters required to - enter/exit specific idle states on a given processor. + ARM and RISC-V systems contain HW capable of managing power consumption + dynamically, where cores can be put in different low-power states (ranging + from simple wfi to power gating) according to OS PM policies. The CPU states + representing the range of dynamic idle states that a processor can enter at + run-time, can be specified through device tree bindings representing the + parameters required to enter/exit specific idle states on a given processor. + + ========================================== + 2 - ARM idle states + ========================================== According to the Server Base System Architecture document (SBSA, [3]), the power states an ARM CPU can be put into are identified by the following list: @@ -43,8 +48,23 @@ description: |+ The device tree binding definition for ARM idle states is the subject of this document. + ========================================== + 3 - RISC-V idle states + ========================================== + + On RISC-V systems, the HARTs (or CPUs) [6] can be put in platform specific + suspend (or idle) states (ranging from simple WFI, power gating, etc). The + RISC-V SBI v0.3 (or higher) [7] hart state management extension provides a + standard mechanism for OS to request HART state transitions. + + The platform specific suspend (or idle) states of a hart can be either + retentive or non-rententive in nature. A retentive suspend state will + preserve HART registers and CSR values for all privilege modes whereas + a non-retentive suspend state will not preserve HART registers and CSR + values. + =========================================== - 2 - idle-states definitions + 4 - idle-states definitions =========================================== Idle states are characterized for a specific system through a set of @@ -211,10 +231,10 @@ description: |+ properties specification that is the subject of the following sections. =========================================== - 3 - idle-states node + 5 - idle-states node =========================================== - ARM processor idle states are defined within the idle-states node, which is + The processor idle states are defined within the idle-states node, which is a direct child of the cpus node [1] and provides a container where the processor idle states, defined as device tree nodes, are listed. @@ -223,7 +243,7 @@ description: |+ just supports idle_standby, an idle-states node is not required. =========================================== - 4 - References + 6 - References =========================================== [1] ARM Linux Kernel documentation - CPUs bindings @@ -238,9 +258,15 @@ description: |+ [4] ARM Architecture Reference Manuals http://infocenter.arm.com/help/index.jsp - [6] ARM Linux Kernel documentation - Booting AArch64 Linux + [5] ARM Linux Kernel documentation - Booting AArch64 Linux Documentation/arm64/booting.rst + [6] RISC-V Linux Kernel documentation - CPUs bindings + Documentation/devicetree/bindings/riscv/cpus.yaml + + [7] RISC-V Supervisor Binary Interface (SBI) + http://github.com/riscv/riscv-sbi-doc/riscv-sbi.adoc + properties: $nodename: const: idle-states @@ -253,7 +279,7 @@ properties: On ARM 32-bit systems this property is optional This assumes that the "enable-method" property is set to "psci" in the cpu - node[6] that is responsible for setting up CPU idle management in the OS + node[5] that is responsible for setting up CPU idle management in the OS implementation. const: psci @@ -265,8 +291,8 @@ patternProperties: as follows. The idle state entered by executing the wfi instruction (idle_standby - SBSA,[3][4]) is considered standard on all ARM platforms and therefore - must not be listed. + SBSA,[3][4]) is considered standard on all ARM and RISC-V platforms and + therefore must not be listed. In addition to the properties listed above, a state node may require additional properties specific to the entry-method defined in the @@ -275,7 +301,27 @@ patternProperties: properties: compatible: - const: arm,idle-state + enum: + - arm,idle-state + - riscv,idle-state + + arm,psci-suspend-param: + $ref: /schemas/types.yaml#/definitions/uint32 + description: | + power_state parameter to pass to the ARM PSCI suspend call. + + Device tree nodes that require usage of PSCI CPU_SUSPEND function + (i.e. idle states node with entry-method property is set to "psci") + must specify this property. + + riscv,sbi-suspend-param: + $ref: /schemas/types.yaml#/definitions/uint32 + description: | + suspend_type parameter to pass to the RISC-V SBI HSM suspend call. + + This property is required in idle state nodes of device tree meant + for RISC-V systems. For more details on the suspend_type parameter + refer the SBI specifiation v0.3 (or higher) [7]. local-timer-stop: description: @@ -317,6 +363,8 @@ patternProperties: description: A string used as a descriptive name for the idle state. + additionalProperties: false + required: - compatible - entry-latency-us @@ -658,4 +706,150 @@ examples: }; }; + - | + // Example 3 (RISC-V 64-bit, 4-cpu systems, two clusters): + + cpus { + #size-cells = <0>; + #address-cells = <1>; + + cpu@0 { + device_type = "cpu"; + compatible = "riscv"; + reg = <0x0>; + riscv,isa = "rv64imafdc"; + mmu-type = "riscv,sv48"; + cpu-idle-states = <&CPU_RET_0_0 &CPU_NONRET_0_0 + &CLUSTER_RET_0 &CLUSTER_NONRET_0>; + + cpu_intc0: interrupt-controller { + #interrupt-cells = <1>; + compatible = "riscv,cpu-intc"; + interrupt-controller; + }; + }; + + cpu@1 { + device_type = "cpu"; + compatible = "riscv"; + reg = <0x1>; + riscv,isa = "rv64imafdc"; + mmu-type = "riscv,sv48"; + cpu-idle-states = <&CPU_RET_0_0 &CPU_NONRET_0_0 + &CLUSTER_RET_0 &CLUSTER_NONRET_0>; + + cpu_intc1: interrupt-controller { + #interrupt-cells = <1>; + compatible = "riscv,cpu-intc"; + interrupt-controller; + }; + }; + + cpu@10 { + device_type = "cpu"; + compatible = "riscv"; + reg = <0x10>; + riscv,isa = "rv64imafdc"; + mmu-type = "riscv,sv48"; + cpu-idle-states = <&CPU_RET_1_0 &CPU_NONRET_1_0 + &CLUSTER_RET_1 &CLUSTER_NONRET_1>; + + cpu_intc10: interrupt-controller { + #interrupt-cells = <1>; + compatible = "riscv,cpu-intc"; + interrupt-controller; + }; + }; + + cpu@11 { + device_type = "cpu"; + compatible = "riscv"; + reg = <0x11>; + riscv,isa = "rv64imafdc"; + mmu-type = "riscv,sv48"; + cpu-idle-states = <&CPU_RET_1_0 &CPU_NONRET_1_0 + &CLUSTER_RET_1 &CLUSTER_NONRET_1>; + + cpu_intc11: interrupt-controller { + #interrupt-cells = <1>; + compatible = "riscv,cpu-intc"; + interrupt-controller; + }; + }; + + idle-states { + CPU_RET_0_0: cpu-retentive-0-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x10000000>; + entry-latency-us = <20>; + exit-latency-us = <40>; + min-residency-us = <80>; + }; + + CPU_NONRET_0_0: cpu-nonretentive-0-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x90000000>; + entry-latency-us = <250>; + exit-latency-us = <500>; + min-residency-us = <950>; + }; + + CLUSTER_RET_0: cluster-retentive-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x11000000>; + local-timer-stop; + entry-latency-us = <50>; + exit-latency-us = <100>; + min-residency-us = <250>; + wakeup-latency-us = <130>; + }; + + CLUSTER_NONRET_0: cluster-nonretentive-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x91000000>; + local-timer-stop; + entry-latency-us = <600>; + exit-latency-us = <1100>; + min-residency-us = <2700>; + wakeup-latency-us = <1500>; + }; + + CPU_RET_1_0: cpu-retentive-1-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x10000010>; + entry-latency-us = <20>; + exit-latency-us = <40>; + min-residency-us = <80>; + }; + + CPU_NONRET_1_0: cpu-nonretentive-1-0 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x90000010>; + entry-latency-us = <250>; + exit-latency-us = <500>; + min-residency-us = <950>; + }; + + CLUSTER_RET_1: cluster-retentive-1 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x11000010>; + local-timer-stop; + entry-latency-us = <50>; + exit-latency-us = <100>; + min-residency-us = <250>; + wakeup-latency-us = <130>; + }; + + CLUSTER_NONRET_1: cluster-nonretentive-1 { + compatible = "riscv,idle-state"; + riscv,sbi-suspend-param = <0x91000010>; + local-timer-stop; + entry-latency-us = <600>; + exit-latency-us = <1100>; + min-residency-us = <2700>; + wakeup-latency-us = <1500>; + }; + }; + }; + ... diff --git a/Documentation/devicetree/bindings/riscv/cpus.yaml b/Documentation/devicetree/bindings/riscv/cpus.yaml index aa5fb64..f62f646 100644 --- a/Documentation/devicetree/bindings/riscv/cpus.yaml +++ b/Documentation/devicetree/bindings/riscv/cpus.yaml @@ -99,6 +99,12 @@ properties: - compatible - interrupt-controller + cpu-idle-states: + $ref: '/schemas/types.yaml#/definitions/phandle-array' + description: | + List of phandles to idle state nodes supported + by this hart (see ./idle-states.yaml). + required: - riscv,isa - interrupt-controller -- 2.7.4