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+# SPDX-License-Identifier: (GPL-2.0 OR MIT)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/riscv/cpus.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V bindings for 'cpus' DT nodes
+
+maintainers:
+ - Paul Walmsley <paul.walmsley@sifive.com>
+ - Palmer Dabbelt <palmer@sifive.com>
+
+description: |
+ This document uses some terminology common to the RISC-V community
+ that is not widely used, the definitions of which are listed here:
+
+ hart: A hardware execution context, which contains all the state
+ mandated by the RISC-V ISA: a PC and some registers. This
+ terminology is designed to disambiguate software's view of execution
+ contexts from any particular microarchitectural implementation
+ strategy. For example, an Intel laptop containing one socket with
+ two cores, each of which has two hyperthreads, could be described as
+ having four harts.
+
+properties:
+ compatible:
+ oneOf:
+ - items:
+ - enum:
+ - sifive,rocket0
+ - sifive,e5
+ - sifive,e51
+ - sifive,u54-mc
+ - sifive,u54
+ - sifive,u5
+ - const: riscv
+ - const: riscv # Simulator only
+ description:
+ Identifies that the hart uses the RISC-V instruction set
+ and identifies the type of the hart.
+
+ mmu-type:
+ description:
+ Identifies the MMU address translation mode used on this
+ hart. These values originate from the RISC-V Privileged
+ Specification document, available from
+ https://riscv.org/specifications/
+ $ref: "/schemas/types.yaml#/definitions/string"
+ enum:
+ - riscv,sv32
+ - riscv,sv39
+ - riscv,sv48
+
+ riscv,isa:
+ description:
+ Identifies the specific RISC-V instruction set architecture
+ supported by the hart. These are documented in the RISC-V
+ User-Level ISA document, available from
+ https://riscv.org/specifications/
+
+ While the isa strings in ISA specification are case
+ insensitive, letters in the riscv,isa string must be all
+ lowercase to simplify parsing.
+ $ref: "/schemas/types.yaml#/definitions/string"
+ enum:
+ - rv64imac
+ - rv64imafdc
+
+ # RISC-V requires 'timebase-frequency' in /cpus, so disallow it here
+ timebase-frequency: false
+
+ interrupt-controller:
+ type: object
+ description: Describes the CPU's local interrupt controller
+
+ properties:
+ '#interrupt-cells':
+ const: 1
+
+ compatible:
+ const: riscv,cpu-intc
+
+ interrupt-controller: true
+
+ required:
+ - '#interrupt-cells'
+ - compatible
+ - interrupt-controller
+
+required:
+ - riscv,isa
+ - interrupt-controller
+
+additionalProperties: true
+
+examples:
+ - |
+ // Example 1: SiFive Freedom U540G Development Kit
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ timebase-frequency = <1000000>;
+ cpu@0 {
+ clock-frequency = <0>;
+ compatible = "sifive,rocket0", "riscv";
+ device_type = "cpu";
+ i-cache-block-size = <64>;
+ i-cache-sets = <128>;
+ i-cache-size = <16384>;
+ reg = <0>;
+ riscv,isa = "rv64imac";
+ cpu_intc0: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+ cpu@1 {
+ clock-frequency = <0>;
+ compatible = "sifive,rocket0", "riscv";
+ d-cache-block-size = <64>;
+ d-cache-sets = <64>;
+ d-cache-size = <32768>;
+ d-tlb-sets = <1>;
+ d-tlb-size = <32>;
+ device_type = "cpu";
+ i-cache-block-size = <64>;
+ i-cache-sets = <64>;
+ i-cache-size = <32768>;
+ i-tlb-sets = <1>;
+ i-tlb-size = <32>;
+ mmu-type = "riscv,sv39";
+ reg = <1>;
+ riscv,isa = "rv64imafdc";
+ tlb-split;
+ cpu_intc1: interrupt-controller {
+ #interrupt-cells = <1>;
+ compatible = "riscv,cpu-intc";
+ interrupt-controller;
+ };
+ };
+ };
+
+ - |
+ // Example 2: Spike ISA Simulator with 1 Hart
+ cpus {
+ #address-cells = <1>;
+ #size-cells = <0>;
+ cpu@0 {
+ device_type = "cpu";
+ reg = <0>;
+ compatible = "riscv";
+ riscv,isa = "rv64imafdc";
+ mmu-type = "riscv,sv48";
+ interrupt-controller {
+ #interrupt-cells = <1>;
+ interrupt-controller;
+ compatible = "riscv,cpu-intc";
+ };
+ };
+ };
+...