Re: [PATCH v3 1/2] dt-bindings: interrupt-controller: Add Xilinx Versal NET SMMU CSR

[Conor Dooley <conor@kernel.org>]

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On Wed, Sep 23, 2026 at 12:46:31PM +0530, Tushar Nimkar wrote:
> From: Anirudha Sarangi <anirudha.sarangi@amd.com>
> 
> Add a device tree binding schema for the Xilinx Versal NET SMMU CSR
> (Control and Status Register) interrupt controller.

This sounds like a very odd name for an interrupt controller.
What else does this block do?

You've actually got a 0x1000 carve out in the example, starting at a
round number, so I suspect this is "fine" and if there's other features
required later you've not painted yourself into a corner by defining a
device for one register. The driver having a starting offset of 0x24 is
another point in your favour.

I'm inclined to ack this, I just want to see an answer first.

Cheers,
Conor.
> 
> The SMMU CSR block acts as a vendor-specific interrupt controller
> in front of the ARM SMMUv3, providing registers to enable and clear
> standard SMMU interrupts such as EVENTQ, CMDQ_SYNC, GERROR and PRIQ.
> Interrupts must be acknowledged in this block before being forwarded
> to the parent interrupt controller (e.g. GIC).
> 
> Signed-off-by: Anirudha Sarangi <anirudha.sarangi@amd.com>
> Co-developed-by: Tushar Nimkar <tushar.nimkar@amd.com>
> Signed-off-by: Tushar Nimkar <tushar.nimkar@amd.com>
> ---
>  .../xlnx,versal-net-smmu-csr.yaml                  | 75 ++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/xlnx,versal-net-smmu-csr.yaml b/Documentation/devicetree/bindings/interrupt-controller/xlnx,versal-net-smmu-csr.yaml
> new file mode 100644
> index 000000000000..38b63e51b732
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/xlnx,versal-net-smmu-csr.yaml
> @@ -0,0 +1,75 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/interrupt-controller/xlnx,versal-net-smmu-csr.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Xilinx Versal NET SMMU CSR Interrupt Controller
> +
> +maintainers:
> +  - Anirudha Sarangi <anirudha.sarangi@amd.com>
> +  - Tushar Nimkar <tushar.nimkar@amd.com>
> +
> +description: |
> +  The Versal NET platform includes a Xilinx-specific SMMU CSR (Control and
> +  Status Register) block that acts as an intermediate interrupt controller
> +  for ARM SMMUv3.
> +
> +  The block provides registers to enable, disable and clear the
> +  standard SMMUv3 interrupt sources (EVENTQ, CMDQ_SYNC, GERROR and PRIQ)
> +  before forwarding them to the parent interrupt controller,
> +  typically a GIC.
> +
> +  The controller receives one parent interrupt and demultiplexes CSR
> +  status bits into the following child interrupt identifiers
> +    0 - EVENTQ
> +    1 - CMDQ_SYNC
> +    2 - GERROR (GLOBAL)
> +    3 - PRIQ
> +
> +allOf:
> +  - $ref: /schemas/interrupt-controller.yaml#
> +
> +properties:
> +  compatible:
> +    const: xlnx,versal-net-smmu-csr
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupt-controller: true
> +
> +  "#interrupt-cells":
> +    const: 1
> +    description: |
> +     Single cell containing the child interrupt identifier
> +      0 - EVENTQ
> +      1 - CMDQ_SYNC
> +      2 - GERROR (GLOBAL)
> +      3 - PRIQ
> +
> +  interrupts:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupt-controller
> +  - "#interrupt-cells"
> +  - interrupts
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    interrupt-controller@eca10000 {
> +        compatible = "xlnx,versal-net-smmu-csr";
> +        reg = <0xeca10000 0x1000>;
> +        interrupt-controller;
> +        #interrupt-cells = <1>;
> +        interrupt-parent = <&gic>;
> +        interrupts = <GIC_SPI 169 IRQ_TYPE_LEVEL_HIGH>;
> +    };
> 
> -- 
> 2.34.1
> 

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