linux-zen-server/Documentation/devicetree/bindings/firmware/nvidia,tegra186-bpmp.yaml

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

title: NVIDIA Tegra Boot and Power Management Processor (BPMP)

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

description: |
  The BPMP is a specific processor in Tegra chip, which is designed for
  booting process handling and offloading the power management, clock
  management, and reset control tasks from the CPU. The binding document
  defines the resources that would be used by the BPMP firmware driver,
  which can create the interprocessor communication (IPC) between the
  CPU and BPMP.

  This node is a mailbox consumer. See the following files for details
  of the mailbox subsystem, and the specifiers implemented by the
  relevant provider(s):

    - .../mailbox/mailbox.txt
    - .../mailbox/nvidia,tegra186-hsp.yaml

  This node is a clock, power domain, and reset provider. See the
  following files for general documentation of those features, and the
  specifiers implemented by this node:

    - .../clock/clock-bindings.txt
    - <dt-bindings/clock/tegra186-clock.h>
    - ../power/power-domain.yaml
    - <dt-bindings/power/tegra186-powergate.h>
    - .../reset/reset.txt
    - <dt-bindings/reset/tegra186-reset.h>

  The BPMP implements some services which must be represented by
  separate nodes. For example, it can provide access to certain I2C
  controllers, and the I2C bindings represent each I2C controller as a
  device tree node. Such nodes should be nested directly inside the main
  BPMP node.

  Software can determine whether a child node of the BPMP node
  represents a device by checking for a compatible property. Any node
  with a compatible property represents a device that can be
  instantiated. Nodes without a compatible property may be used to
  provide configuration information regarding the BPMP itself, although
  no such configuration nodes are currently defined by this binding.

  The BPMP firmware defines no single global name-/numbering-space for
  such services. Put another way, the numbering scheme for I2C buses is
  distinct from the numbering scheme for any other service the BPMP may
  provide (e.g. a future hypothetical SPI bus service). As such, child
  device nodes will have no reg property, and the BPMP node will have no
  "#address-cells" or "#size-cells" property.

  The shared memory area for the IPC TX and RX between CPU and BPMP are
  predefined and work on top of sysram, which is an SRAM inside the
  chip. See ".../sram/sram.yaml" for the bindings.  

properties:
  compatible:
    oneOf:
      - items:
          - enum:
              - nvidia,tegra194-bpmp
              - nvidia,tegra234-bpmp
          - const: nvidia,tegra186-bpmp
      - const: nvidia,tegra186-bpmp

  mboxes:
    description: A phandle and channel specifier for the mailbox used to
      communicate with the BPMP.
    maxItems: 1

  shmem:
    description: List of the phandle to the TX and RX shared memory area
      that the IPC between CPU and BPMP is based on.
    minItems: 2
    maxItems: 2

  "#clock-cells":
    const: 1

  "#power-domain-cells":
    const: 1

  "#reset-cells":
    const: 1

  interconnects:
    items:
      - description: memory read client
      - description: memory write client
      - description: DMA read client
      - description: DMA write client

  interconnect-names:
    items:
      - const: read
      - const: write
      - const: dma-mem # dma-read
      - const: dma-write

  iommus:
    maxItems: 1

  i2c:
    type: object

  thermal:
    type: object

additionalProperties: false

required:
  - compatible
  - mboxes
  - shmem
  - "#clock-cells"
  - "#power-domain-cells"
  - "#reset-cells"

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

    sram@30000000 {
        compatible = "nvidia,tegra186-sysram", "mmio-sram";
        reg = <0x30000000 0x50000>;
        #address-cells = <1>;
        #size-cells = <1>;
        ranges = <0x0 0x30000000 0x50000>;

        cpu_bpmp_tx: sram@4e000 {
            reg = <0x4e000 0x1000>;
            label = "cpu-bpmp-tx";
            pool;
        };

        cpu_bpmp_rx: sram@4f000 {
            reg = <0x4f000 0x1000>;
            label = "cpu-bpmp-rx";
            pool;
        };
    };

    bpmp {
        compatible = "nvidia,tegra186-bpmp";
        interconnects = <&mc TEGRA186_MEMORY_CLIENT_BPMPR &emc>,
                        <&mc TEGRA186_MEMORY_CLIENT_BPMPW &emc>,
                        <&mc TEGRA186_MEMORY_CLIENT_BPMPDMAR &emc>,
                        <&mc TEGRA186_MEMORY_CLIENT_BPMPDMAW &emc>;
        interconnect-names = "read", "write", "dma-mem", "dma-write";
        iommus = <&smmu TEGRA186_SID_BPMP>;
        mboxes = <&hsp_top0 TEGRA_HSP_MBOX_TYPE_DB
                            TEGRA_HSP_DB_MASTER_BPMP>;
        shmem = <&cpu_bpmp_tx>, <&cpu_bpmp_rx>;
        #clock-cells = <1>;
        #power-domain-cells = <1>;
        #reset-cells = <1>;

        i2c {
            compatible = "nvidia,tegra186-bpmp-i2c";
            nvidia,bpmp-bus-id = <5>;
            #address-cells = <1>;
            #size-cells = <0>;
        };

        thermal {
            compatible = "nvidia,tegra186-bpmp-thermal";
            #thermal-sensor-cells = <1>;
        };
    };