Re: [PATCH v3 1/2] dt-bindings: remoteproc: add Microchip IPC remoteproc

[Rob Herring <robh@kernel.org>]

On Mon, Jan 26, 2026 at 12:06:57PM +0000, Valentina Fernandez wrote:
> Microchip RISC-V SoCs typically contain one or more clusters. Clusters
> can operate in Asymmetric Multi-Processing (AMP) mode, where individual
> cores or groups of cores run as independent software contexts.
> 
> The compatible is intentionally generic, representing a “generic” SBI
> ecall interface to a set of remote processors, with the platform
> abstracted  via SBI ecalls. The IPC/IHC (named differently depending on
> whether it is RTL for the FPGA fabric or a hardened version) is
> intended for Asymmetric Multiprocessing, where a set of cores or
> clusters can run other firmware, such as Zephyr.
> 
> Unlike platforms with a fixed DSP, the configuration here is variable
> even for a single SoC. For example, which memory regions are used for
> the remote cluster or which mailbox channel is selected. This binding
> documents that firmware interface.
> 
> Signed-off-by: Valentina Fernandez <valentina.fernandezalanis@microchip.com>
> ---
>  .../microchip,ipc-sbi-remoteproc.yaml         | 131 ++++++++++++++++++
>  1 file changed, 131 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/remoteproc/microchip,ipc-sbi-remoteproc.yaml
> 
> diff --git a/Documentation/devicetree/bindings/remoteproc/microchip,ipc-sbi-remoteproc.yaml b/Documentation/devicetree/bindings/remoteproc/microchip,ipc-sbi-remoteproc.yaml
> new file mode 100644
> index 000000000000..6fc0ab7f3ffb
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/remoteproc/microchip,ipc-sbi-remoteproc.yaml
> @@ -0,0 +1,131 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/remoteproc/microchip,ipc-sbi-remoteproc.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Microchip IPC Remote Processor
> +
> +description:

Need '>' to maintain paragraph formatting.

> +  Microchip RISC-V SoCs typically contain one or more clusters. Clusters can
> +  operate in Asymmetric Multi-Processing (AMP) mode, where individual cores
> +  or groups of cores run as independent software contexts.
> +
> +  The configuration is flexible, as the set of cores or clusters that can be
> +  controlled as remote processors may vary, and memory regions used for
> +  firmware as well as mailbox assignments depend on the system design.
> +
> +  Communication with remote cores or clusters is abstracted using ecalls
> +  to the platform's Supervisor Binary Interface (SBI) firmware, through
> +  which the state of remote cores or clusters are controlled. This binding
> +  documents that firmware interface.
> +
> +maintainers:
> +  - Valentina Fernandez <valentina.fernandezalanis@microchip.com>
> +
> +properties:
> +  compatible:
> +    const: microchip,ipc-sbi-remoteproc
> +
> +  cpu:
> +    description:
> +      phandles to the CPUs comprising the remote cluster

More than 1? Then should be 'cpus'.

> +    $ref: /schemas/types.yaml#/definitions/phandle-array

Already has a type. Drop.

> +
> +  mboxes:
> +    description:
> +      Microchip IPC mailbox specifier. Used for communication with
> +      a remote cluster. For HSS versions prior to v2026.04, it is also
> +      used for controlling the life cycle of a remote cluster. The
> +      specifier format is as per the bindings in
> +      Documentation/devicetree/bindings/mailbox/microchip,sbi-ipc.yaml
> +    maxItems: 1
> +
> +  memory-region:
> +    minItems: 1
> +    maxItems: 5
> +    description:
> +      List of phandles to the reserved memory regions associated wih the
> +      remoteproc device. This is variable and describes the memories shared
> +      with the remote cluster (e.g. firmware, resource table, rpmsg vrings)
> +    items:
> +      anyOf:
> +        - description: resource table when firmware is started by the bootloader
> +        - description: remote cluster firmware image section
> +        - description: virtio device (vdev) buffer
> +        - description: vring0
> +        - description: vring1
> +
> +  memory-region-names:
> +    minItems: 1
> +    maxItems: 5
> +    items:
> +      anyOf:

Use 'enum'

> +        - const: rsc-table
> +        - const: firmware
> +        - const: buffer
> +        - const: vring0
> +        - const: vring1
> +
> +required:
> +  - compatible
> +
> +# Remote Cluster ID is derived either from the CPU phandle or
> +# from the mailbox specifier prior to HSS v2026.04
> +anyOf:
> +  - required:
> +      - cpu
> +  - required:
> +      - mboxes
> +
> +allOf:
> +  - if:
> +      properties:
> +        memory-region-names:
> +          contains:
> +            enum:
> +              - vring0
> +              - vring1
> +    then:
> +      properties:
> +        memory-region-names:
> +          contains:
> +            const: buffer
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    // Early boot mode example - firmware started by bootloader
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        remoteproc {
> +            compatible = "microchip,ipc-sbi-remoteproc";
> +            cpu = <&cpu4>;
> +            mboxes= <&ihc 8>;
> +            memory-region = <&rsctable>, <&vdev0buffer>,
> +                            <&vdev0vring0>, <&vdev0vring1>;
> +            memory-region-names = "rsc-table", "buffer",
> +                                  "vring0", "vring1";
> +        };
> +    };
> +
> +  - |
> +    // Late boot mode example - firmware started by Linux (remoteproc)
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        remoteproc {
> +            compatible = "microchip,ipc-sbi-remoteproc";
> +            cpu = <&cpu4>;
> +            mboxes= <&ihc 8>;
> +            memory-region = <&cluster_firmware>, <&vdev0buffer>,
> +                            <&vdev0vring0>, <&vdev0vring1>;
> +            memory-region-names = "firmware", "buffer",
> +                                  "vring0", "vring1";
> +        };
> +    };
> +...
> -- 
> 2.34.1
>