Re: [RFC PATCH v4 1/8] dt-bindings: bus: add CDX bus device tree bindings

[Rob Herring]

On Fri, Oct 14, 2022 at 10:10:42AM +0530, Nipun Gupta wrote:
> This patch adds a devicetree binding documentation for CDX
> bus.

Please read submitting-patches.rst and what it says about commit 
messages.

> 
> Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
> ---
>  .../devicetree/bindings/bus/xlnx,cdx.yaml     | 65 +++++++++++++++++++
>  MAINTAINERS                                   |  6 ++
>  2 files changed, 71 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
> 
> diff --git a/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml b/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
> new file mode 100644
> index 000000000000..984ff65b668a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
> @@ -0,0 +1,65 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/bus/xlnx,cdx.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: AMD CDX bus controller
> +
> +description: |
> +  CDX bus controller detects CDX devices using CDX firmware and
> +  add those to cdx bus. The CDX bus manages multiple FPGA based
> +  hardware devices, which can support network, crypto or any other
> +  specialized type of devices. These FPGA based devices can be
> +  added/modified dynamically on run-time.
> +
> +  All devices on the CDX bus will have a unique streamid (for IOMMU)
> +  and a unique device ID (for MSI) corresponding to a requestor ID
> +  (one to one associated with the device). The streamid and deviceid
> +  are used to configure SMMU and GIC-ITS respectively.
> +
> +  iommu-map property is used to define the set of stream ids
> +  corresponding to each device and the associated IOMMU.
> +
> +  The MSI writes are accompanied by sideband data (Device ID).
> +  The msi-map property is used to associate the devices with the
> +  device ID as well as the associated ITS controller.
> +
> +maintainers:
> +  - Nipun Gupta <nipun.gupta@xxxxxxx>
> +  - Nikhil Agarwal <nikhil.agarwal@xxxxxxx>
> +
> +properties:
> +  compatible:
> +    const: xlnx,cdxbus-controller-1.0

Where does 1.0 come from?

> +
> +  reg:
> +    maxItems: 1
> +
> +  iommu-map: true
> +
> +  msi-map: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - iommu-map
> +  - msi-map
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        cdx: cdx@4000000 {

bus@...

> +            compatible = "xlnx,cdxbus-controller-1.0";
> +            reg = <0x00000000 0x04000000 0 0x1000>;
> +            /* define map for RIDs 250-259 */
> +            iommu-map = <250 &smmu 250 10>;
> +            /* define msi map for RIDs 250-259 */
> +            msi-map = <250 &its 250 10>;
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index f5ca4aefd184..5f48f11fe0c3 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -935,6 +935,12 @@ S:	Supported
>  F:	drivers/crypto/ccp/
>  F:	include/linux/ccp.h
>  
> +AMD CDX BUS DRIVER
> +M:	Nipun Gupta <nipun.gupta@xxxxxxx>
> +M:	Nikhil Agarwal <nikhil.agarwal@xxxxxxx>
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/bus/xlnx,cdx.yaml
> +
>  AMD CRYPTOGRAPHIC COPROCESSOR (CCP) DRIVER - SEV SUPPORT
>  M:	Brijesh Singh <brijesh.singh@xxxxxxx>
>  M:	Tom Lendacky <thomas.lendacky@xxxxxxx>
> -- 
> 2.25.1
> 
>