Documentation/devicetree/bindings/soc/qcom/qcom,smsm.yaml

# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
%YAML 1.2
---
$id: http://devicetree.org/schemas/soc/qcom/qcom,smsm.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: Qualcomm Shared Memory State Machine

maintainers:
  - Andy Gross <agross@kernel.org>
  - Bjorn Andersson <bjorn.andersson@linaro.org>
  - Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

description:
  The Shared Memory State Machine facilitates broadcasting of single bit state
  information between the processors in a Qualcomm SoC. Each processor is
  assigned 32 bits of state that can be modified. A processor can through a
  matrix of bitmaps signal subscription of notifications upon changes to a
  certain bit owned by a certain remote processor.

properties:
  compatible:
    const: qcom,smsm

  '#address-cells':
    const: 1

  qcom,local-host:
    $ref: /schemas/types.yaml#/definitions/uint32
    default: 0
    description:
      Identifier of the local processor in the list of hosts, or in other words
      specifier of the column in the subscription matrix representing the local
      processor.

  '#size-cells':
    const: 0

patternProperties:
  "^qcom,ipc-[1-4]$":
    $ref: /schemas/types.yaml#/definitions/phandle-array
    items:
      - items:
          - description: phandle to a syscon node representing the APCS registers
          - description: u32 representing offset to the register within the syscon
          - description: u32 representing the ipc bit within the register
    description:
      Three entries specifying the outgoing ipc bit used for signaling the N:th
      remote processor.

  "@[0-9a-f]$":
    type: object
    description:
      Each processor's state bits are described by a subnode of the SMSM device
      node.  Nodes can either be flagged as an interrupt-controller to denote a
      remote processor's state bits or the local processors bits.  The node
      names are not important.

    properties:
      reg:
        maxItems: 1

      interrupt-controller:
        description:
          Marks the entry as a interrupt-controller and the state bits to
          belong to a remote processor.

      '#interrupt-cells':
        const: 2

      interrupts:
        maxItems: 1
        description:
          One entry specifying remote IRQ used by the remote processor to
          signal changes of its state bits.

      '#qcom,smem-state-cells':
        $ref: /schemas/types.yaml#/definitions/uint32
        const: 1
        description:
          Required for local entry. Denotes bit number.

    required:
      - reg

    oneOf:
      - required:
          - '#qcom,smem-state-cells'
      - required:
          - interrupt-controller
          - '#interrupt-cells'
          - interrupts

    additionalProperties: false

required:
  - compatible
  - '#address-cells'
  - '#size-cells'

anyOf:
  - required:
      - qcom,ipc-1
  - required:
      - qcom,ipc-2
  - required:
      - qcom,ipc-3
  - required:
      - qcom,ipc-4

additionalProperties: false

examples:
  # The following example shows the SMEM setup for controlling properties of
  # the wireless processor, defined from the 8974 apps processor's
  # point-of-view. It encompasses one outbound entry and the outgoing interrupt
  # for the wireless processor.
  - |
    #include <dt-bindings/interrupt-controller/arm-gic.h>

    shared-memory {
        compatible = "qcom,smsm";
        #address-cells = <1>;
        #size-cells = <0>;
        qcom,ipc-3 = <&apcs 8 19>;

        apps_smsm: apps@0 {
            reg = <0>;
            #qcom,smem-state-cells = <1>;
        };

        wcnss_smsm: wcnss@7 {
            reg = <7>;
            interrupts = <GIC_SPI 144 IRQ_TYPE_EDGE_RISING>;
            interrupt-controller;
            #interrupt-cells = <2>;
        };
    };