[PATCH v2 02/11] dt-bindings: Add binding for gunyah hypervisor

[Dmitry Baryshkov]

On 02/08/2022 00:12, Elliot Berman wrote:
> When Linux is booted as a guest under the Gunyah hypervisor, Gunyah
> applies a devicetree overlay describing the virtual platform
> configuration of the guest VM, such as the message queue capability IDs
> for communicating with the Resource Manager. Add the DT bindings that
> Gunyah adheres for the hypervisor node and message queues.
> 
> Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
> ---
>   .../bindings/firmware/gunyah-hypervisor.yaml  | 84 +++++++++++++++++++
>   MAINTAINERS                                   |  1 +
>   2 files changed, 85 insertions(+)
>   create mode 100644 Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> new file mode 100644
> index 000000000000..e50d932e768c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
> @@ -0,0 +1,84 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/gunyah-hypervisor.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Gunyah Hypervisor
> +
> +maintainers:
> +  - Murali Nalajala <quic_mnalajal at quicinc.com>
> +  - Elliot Berman <quic_eberman at quicinc.com>
> +
> +description: |+
> +  On systems which support devicetree, Gunyah generates and overlays a deviceetree overlay which
> +  describes the basic configuration of the hypervisor. Virtual machines use this information for
> +  initial discovery that they are running as a Gunyah guest VM.
> +  See also: https://github.com/quic/gunyah-resource-manager/blob/develop/src/vm_creation/dto_construct.c
> +
> +properties:
> +  compatible:
> +    oneOf:
> +      - items:
> +          - const: gunyah-hypervisor-1.0
> +          - const: gunyah-hypervisor

Just:
  - items:
   - const: gunyah-hypervisor-1.0
   - const: gunyah-hypervisor

oneOf is not necessary

> +
> +  "#address-cells":
> +    description: Number of cells needed to represent 64-bit capability IDs.
> +    const: 2
> +  "#size-cells":
> +    description: must be 0, because capability IDs are not memory address
> +                  ranges and do not have a size.
> +    const: 0
> +
> +patternProperties:
> +  "^gunyah-resource-mgr(@.*)?":
> +    type: object
> +    description:
> +      Resource Manager node which is required to communicate to Resource
> +      Manager VM using Gunyah Message Queues.
> +
> +    properties:
> +      compatible:
> +        oneOf:

Again, please drop the oneOf.

> +          - items:
> +              - const: gunyah-resource-manager-1-0
> +              - const: gunyah-resource-manager
> +      reg:
> +        items:
> +          - description: Gunyah capability ID of the TX message queue
> +          - description: Gunyah capability ID of the RX message queue
> +      interrupts:
> +        items:
> +          - description: Interrupt for the TX message queue
> +          - description: Interrupt for the RX message queue
> +    additionalProperties: false
> +    required:
> +      - compatible
> +      - reg
> +      - interrupts
> +
> +additionalProperties: false
> +
> +required:
> +  - compatible
> +  - "#address-cells"
> +  - "#size-cells"
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    hypervisor {
> +        #address-cells = <2>;
> +        #size-cells = <0>;
> +        compatible = "gunyah-hypervisor-1.0", "gunyah-hypervisor";
> +
> +        gunyah-resource-mgr at 1 {
> +            compatible = "gunyah-resource-manager-1-0", "gunyah-resource-manager";
> +            interrupts = <GIC_SPI 3 IRQ_TYPE_EDGE_RISING>, /* TX full IRQ */
> +                         <GIC_SPI 4 IRQ_TYPE_EDGE_RISING>; /* RX empty IRQ */
> +            reg = <0x00000000 0x00000000>, <0x00000000 0x00000001>;
> +                  /* TX, RX cap ids */

Do these cap ids persist from platform to platform? Then you might want 
to define generic values for these caps.

Also it feels like you are misusing the #address-cells/reg properties. 
For example, the device should have its @NNNN to be equal to the first 
addres. But you are using the second reg.

I think that using a separate property with /bits/ 64 might be a better 
solution.

> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 18fb034526e1..0cd12ea6c11c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -8741,6 +8741,7 @@ M:	Elliot Berman <quic_eberman at quicinc.com>
>   M:	Murali Nalajala <quic_mnalajal at quicinc.com>
>   L:	linux-arm-msm at vger.kernel.org
>   S:	Maintained
> +F:	Documentation/devicetree/bindings/firmware/gunyah-hypervisor.yaml
>   F:	Documentation/virt/gunyah/
>   
>   HABANALABS PCI DRIVER


-- 
With best wishes
Dmitry