Documentation/devicetree/bindings/mailbox/nvidia,tegra186-hsp.yaml

# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
%YAML 1.2
---
$id: http://devicetree.org/schemas/mailbox/nvidia,tegra186-hsp.yaml#
$schema: http://devicetree.org/meta-schemas/core.yaml#

title: NVIDIA Tegra Hardware Synchronization Primitives (HSP)

maintainers:
  - Thierry Reding <thierry.reding@gmail.com>
  - Jon Hunter <jonathanh@nvidia.com>

description: |
  The HSP modules are used for the processors to share resources and
  communicate together. It provides a set of hardware synchronization
  primitives for interprocessor communication. So the interprocessor
  communication (IPC) protocols can use hardware synchronization
  primitives, when operating between two processors not in an SMP
  relationship.

  The features that HSP supported are shared mailboxes, shared
  semaphores, arbitrated semaphores and doorbells.

  The mbox specifier of the "mboxes" property in the client node should
  contain two cells. The first cell determines the HSP type and the
  second cell is used to identify the mailbox that the client is going
  to use.

  For shared mailboxes, the first cell composed of two fields:
    - bits 15..8:
        A bit mask of flags that further specifies the type of shared
        mailbox to be used (based on the data size). If no flag is
        specified then, 32-bit shared mailbox is used.
    - bits 7..0:
        Defines the type of the mailbox to be used. This field should be
        TEGRA_HSP_MBOX_TYPE_SM for shared mailboxes.

  For doorbells, the second cell specifies the index of the doorbell to
  use.

  For shared mailboxes, the second cell is composed of two fields:
    - bits 31..24:
        A bit mask of flags that further specify how the shared mailbox
        will be used. Valid flags are:
          - bit 31:
              Defines the direction of the mailbox. If set, the mailbox
              will be used as a producer (i.e. used to send data). If
              cleared, the mailbox is the consumer of data sent by a
              producer.

    - bits 23..0:
        The index of the shared mailbox to use. The number of available
        mailboxes may vary by instance of the HSP block and SoC
        generation.

    The following file contains definitions that can be used to
    construct mailbox specifiers:

        <dt-bindings/mailbox/tegra186-hsp.h>

properties:
  $nodename:
    pattern: "^hsp@[0-9a-f]+$"

  compatible:
    oneOf:
      - const: nvidia,tegra186-hsp
      - const: nvidia,tegra194-hsp
      - items:
          - const: nvidia,tegra234-hsp
          - const: nvidia,tegra194-hsp

  reg:
    maxItems: 1

  interrupts:
    minItems: 1
    maxItems: 9

  interrupt-names:
    oneOf:
      # shared interrupts are optional
      - items:
          - const: doorbell

      - items:
          - const: doorbell
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"

      - items:
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"
          - pattern: "^shared[0-7]$"

  "#mbox-cells":
    const: 2

additionalProperties: false

examples:
  - |
    #include <dt-bindings/interrupt-controller/arm-gic.h>
    #include <dt-bindings/mailbox/tegra186-hsp.h>

    hsp_top0: hsp@3c00000 {
        compatible = "nvidia,tegra186-hsp";
        reg = <0x03c00000 0xa0000>;
        interrupts = <GIC_SPI 176 IRQ_TYPE_LEVEL_HIGH>;
        interrupt-names = "doorbell";
        #mbox-cells = <2>;
    };

    client {
        mboxes = <&hsp_top0 TEGRA_HSP_MBOX_TYPE_DB TEGRA_HSP_DB_MASTER_CCPLEX>;
    };