Qualcomm KPSS Watchdog Timer

Qualcomm KPSS 워치독

GPL-2.0-only 또는 BSD-2-Clause로 배포되는 이 스키마는 Qualcomm Krait Processor Sub-system(KPSS) Watchdog Timer를 정의합니다. 관리자는 Rajendra Nayak입니다.

노드 이름과 APSS·KPSS 호환 계열

노드 이름은 `watchdog@주소` 또는 `timer@주소` 형식이어야 합니다. 현대 계열은 SoC별 문자열 뒤에 `qcom,kpss-wdt`를 fallback으로 둡니다.

SoC별 문자열에는 `qcom,kpss-wdt-ipq4019`와 IPQ5018·IPQ5332·IPQ5424·IPQ9574, MSM8226·MSM8974·MSM8994, QCM2290, QCS404·QCS615·QCS8300, SA8255P·SA8775P, SC7180·SC7280·SC8180X·SC8280XP, SDM845, SDX55·SDX65, SM6115·SM6350·SM8150·SM8250의 `qcom,apss-wdt-*` 문자열이 포함됩니다.

단독 `qcom,kpss-wdt`는 deprecated입니다. SCSS timer는 `qcom,scss-timer`와 `qcom,msm-timer`를 함께 사용합니다. APQ8064, IPQ8064, MDM9615, MSM8960용 legacy KPSS는 SoC별 `qcom,kpss-wdt-*` 뒤에 `qcom,kpss-timer`, `qcom,msm-timer`를 차례로 나열합니다.

properties:
  $nodename:
    pattern: "^(watchdog|timer)@[0-9a-f]+$"

  compatible:
    oneOf:
      - items:
          - enum:
              - qcom,kpss-wdt-ipq4019
              - qcom,apss-wdt-ipq5018
              - qcom,apss-wdt-ipq5332
              - qcom,apss-wdt-ipq5424
              - qcom,apss-wdt-ipq9574
              - qcom,apss-wdt-msm8226
              - qcom,apss-wdt-msm8974
              - qcom,apss-wdt-msm8994
              - qcom,apss-wdt-qcm2290
              - qcom,apss-wdt-qcs404
              - qcom,apss-wdt-qcs615
              - qcom,apss-wdt-qcs8300
              - qcom,apss-wdt-sa8255p
              - qcom,apss-wdt-sa8775p
              - qcom,apss-wdt-sc7180
              - qcom,apss-wdt-sc7280
              - qcom,apss-wdt-sc8180x
              - qcom,apss-wdt-sc8280xp
              - qcom,apss-wdt-sdm845
              - qcom,apss-wdt-sdx55
              - qcom,apss-wdt-sdx65
              - qcom,apss-wdt-sm6115
              - qcom,apss-wdt-sm6350
              - qcom,apss-wdt-sm8150
              - qcom,apss-wdt-sm8250
          - const: qcom,kpss-wdt
      - const: qcom,kpss-wdt
        deprecated: true
      - items:
          - const: qcom,scss-timer
          - const: qcom,msm-timer
      - items:
          - enum:
              - qcom,kpss-wdt-apq8064
              - qcom,kpss-wdt-ipq8064
              - qcom,kpss-wdt-mdm9615
              - qcom,kpss-wdt-msm8960
          - const: qcom,kpss-timer
          - const: qcom,msm-timer

클록·CPU offset·interrupt 수

`reg`와 `clocks`는 각각 항목 하나만 받습니다. `clock-names`의 이름은 `sleep`이고, `clock-frequency`는 general purpose timer 주파수를 Hz 단위로 지정합니다.

`cpu-offset`은 CPU remapping 기능 없이 timer에 접근할 때 쓰는 per-CPU offset입니다. 실제 offset은 `cpu-offset + (0x10000 * cpu-nr)`로 계산합니다. `interrupts`는 최소 1개, 최대 5개입니다.

`compatible`, `reg`, `clocks`가 필수입니다.

  reg:
    maxItems: 1

  clocks:
    maxItems: 1

  clock-names:
    items:
      - const: sleep

  clock-frequency:
    description:
      The frequency of the general purpose timer in Hz.

  cpu-offset:
    $ref: /schemas/types.yaml#/definitions/uint32
    description:
      Per-CPU offset used when the timer is accessed without the CPU remapping
      facilities. The offset is cpu-offset + (0x10000 * cpu-nr).

  interrupts:
    minItems: 1
    maxItems: 5

required:
  - compatible
  - reg
  - clocks

KPSS Bark·Bite와 legacy timer 조건

공통 `watchdog.yaml`을 상속합니다. `compatible` 목록에 `qcom,kpss-wdt`가 있으면 `clock-frequency`와 `cpu-offset`을 사용할 수 없습니다. 이 경우 interrupt는 Bark와 Bite 순서이며 최소 한 항목을 제공합니다.

그 밖의 legacy timer 형식은 interrupt가 최소 3개 필요하고, 순서는 Debug, 첫 번째 general purpose timer, 두 번째 general purpose timer, 첫 번째 watchdog, 두 번째 watchdog입니다. 이 형식에서는 `clock-frequency`가 필수입니다. 평가되지 않은 속성은 허용하지 않습니다.

allOf:
  - $ref: watchdog.yaml#

  - if:
      properties:
        compatible:
          contains:
            const: qcom,kpss-wdt
    then:
      properties:
        clock-frequency: false
        cpu-offset: false
        interrupts:
          minItems: 1
          items:
            - description: Bark
            - description: Bite

    else:
      properties:
        interrupts:
          minItems: 3
          items:
            - description: Debug
            - description: First general purpose timer
            - description: Second general purpose timer
            - description: First watchdog
            - description: Second watchdog
      required:
        - clock-frequency

unevaluatedProperties: false

SM8150 APSS 예제

첫 번째 예제는 SM8150 APSS 워치독에 `qcom,kpss-wdt` fallback을 지정하고 주소 `0x17c10000`, sleep clock, rising-edge GIC SPI 0, timeout 10초를 설정합니다.

examples:
  - |
    #include <dt-bindings/interrupt-controller/arm-gic.h>

    watchdog@17c10000 {
        compatible = "qcom,apss-wdt-sm8150", "qcom,kpss-wdt";
        reg = <0x17c10000 0x1000>;
        clocks = <&sleep_clk>;
        interrupts = <GIC_SPI 0 IRQ_TYPE_EDGE_RISING>;
        timeout-sec = <10>;
    };

IPQ8064 legacy timer 예제

두 번째 예제는 IPQ8064 legacy KPSS timer에 다섯 GIC PPI를 순서대로 연결합니다. register는 `0x0200a000`, timer 주파수는 25MHz, clock 이름은 `sleep`, per-CPU offset은 `0x80000`입니다.

- |
  #include <dt-bindings/interrupt-controller/arm-gic.h>

  watchdog@200a000 {
      compatible = "qcom,kpss-wdt-ipq8064", "qcom,kpss-timer", "qcom,msm-timer";
      interrupts = <GIC_PPI 1 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>,
                   <GIC_PPI 2 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>,
                   <GIC_PPI 3 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>,
                   <GIC_PPI 4 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>,
                   <GIC_PPI 5 (GIC_CPU_MASK_SIMPLE(2) | IRQ_TYPE_EDGE_RISING)>;
      reg = <0x0200a000 0x100>;
      clock-frequency = <25000000>;
      clocks = <&sleep_clk>;
      clock-names = "sleep";
      cpu-offset = <0x80000>;
  };