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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 CPUs
maintainers:
- Paul Walmsley <paul.walmsley@sifive.com>
- Palmer Dabbelt <palmer@sifive.com>
- Conor Dooley <conor@kernel.org>
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:
- andestech,ax45mp
- canaan,k210
- sifive,bullet0
- sifive,e5
- sifive,e7
- sifive,e71
- sifive,rocket0
- sifive,s7
- sifive,u5
- sifive,u54
- sifive,u7
- sifive,u74
- sifive,u74-mc
- thead,c906
- thead,c910
- const: riscv
- items:
- enum:
- sifive,e51
- sifive,u54-mc
- const: sifive,rocket0
- 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,sv57
- riscv,none
riscv,cbom-block-size:
$ref: /schemas/types.yaml#/definitions/uint32
description:
The blocksize in bytes for the Zicbom cache operations.
riscv,cboz-block-size:
$ref: /schemas/types.yaml#/definitions/uint32
description:
The blocksize in bytes for the Zicboz cache operations.
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/
Due to revisions of the ISA specification, some deviations
have arisen over time.
Notably, riscv,isa was defined prior to the creation of the
Zicsr and Zifencei extensions and thus "i" implies
"zicsr_zifencei".
While the isa strings in ISA specification are case
insensitive, letters in the riscv,isa string must be all
lowercase to simplify parsing.
$ref: "/schemas/types.yaml#/definitions/string"
pattern: ^rv(?:64|32)imaf?d?q?c?b?k?j?p?v?h?(?:[hsxz](?:[a-z])+)?(?:_[hsxz](?:[a-z])+)*$
# 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
cpu-idle-states:
$ref: '/schemas/types.yaml#/definitions/phandle-array'
items:
maxItems: 1
description: |
List of phandles to idle state nodes supported
by this hart (see ./idle-states.yaml).
capacity-dmips-mhz:
description:
u32 value representing CPU capacity (see ../cpu/cpu-capacity.txt) in
DMIPS/MHz, relative to highest capacity-dmips-mhz
in the system.
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";
};
};
};
...
|
