Documentation/devicetree/bindings/timer/arm,arch_timer.yaml

Source file repositories/reference/linux-study-clean/Documentation/devicetree/bindings/timer/arm,arch_timer.yaml

File Facts

System
Linux kernel
Corpus path
Documentation/devicetree/bindings/timer/arm,arch_timer.yaml
Extension
.yaml
Size
3919 bytes
Lines
124
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: configuration, schema, or hardware description
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

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Annotated Snippet

# SPDX-License-Identifier: GPL-2.0
%YAML 1.2
---
$id: http://devicetree.org/schemas/timer/arm,arch_timer.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: ARM architected timer

maintainers:
  - Marc Zyngier <marc.zyngier@arm.com>
  - Mark Rutland <mark.rutland@arm.com>
description: |+
  The per-core architected timer is expected to deliver per-CPU interrupts
  (commonly to a GIC to deliver its per-processor interrupts as PPIs).

properties:
  compatible:
    oneOf:
      - items:
          - const: arm,cortex-a15-timer
          - const: arm,armv7-timer
      - items:
          - enum:
              - arm,armv7-timer
              - arm,armv8-timer
      - items:
          - const: arm,armv8-timer
          - const: arm,armv7-timer

  interrupts:
    minItems: 2
    items:
      - description: EL1 secure physical timer irq, if EL3 is implemented
      - description: EL1 non-secure physical timer irq
      - description: EL1 virtual timer irq
      - description: EL2 physical timer irq, if EL2 is implemented
      - description: EL2 virtual timer irq, if FEAT_VHE is implemented

  interrupt-names:
    oneOf:
      - minItems: 2
        items:
          - const: phys
          - const: virt
          - const: hyp-phys
          - const: hyp-virt
      - minItems: 3
        items:
          - const: sec-phys
          - const: phys
          - const: virt
          - const: hyp-phys
          - const: hyp-virt

  clock-frequency:
    description: The frequency of the main counter, in Hz. Should be present
      only where necessary to work around broken firmware which does not configure
      CNTFRQ on all CPUs to a uniform correct value. Use of this property is
      strongly discouraged; fix your firmware unless absolutely impossible.

  always-on:
    type: boolean
    description: If present, the timer is powered through an always-on power
      domain, therefore it never loses context.

  allwinner,erratum-unknown1:
    type: boolean
    description: Indicates the presence of an erratum found in Allwinner SoCs,
      where reading certain values from the counter is unreliable. This also
      affects writes to the tval register, due to the implicit counter read.

Annotation

Implementation Notes