Re: [PATCH v6] dt-bindings: iommu: Convert msm,iommu-v0 to yaml

[Rob Herring <robh@kernel.org>]

On Tue, Dec 19, 2023 at 09:28:27PM +0100, David Heidelberg wrote:
> Convert Qualcomm IOMMU v0 implementation to yaml format.
> 
> iommus part being ommited for the other bindings, as mdp4 one.
> 
> Signed-off-by: David Heidelberg <david@ixit.cz>
> ---
> v6:
>  - clean iommu-cells description (thx @Robin)
> v5:
>  - updated example (thx @Konrad)
>  - ordering of requirements + dropped > and | and reformatted (thx @Konrad)
> v4:
>  - renamed to qcom,apq8064-iommu as Rob requested
>  - changed title to Qualcomm APQ8064 IOMMU
>  - dropped quotes around URLs
>  - dropped mdp node
>  - dropped unused mdp_port0 label
> 
> v3:
>  - I kept the name as -v0, since we have other binding -v1 and it look
>    good, I can change thou in v4 if requested.
>  - dropped non-existent smmu_clk part (and adjusted example, which was
>    using it)
>  - dropped iommu description
>  - moved iommu-cells description to the property #iommu-cells
> 
> v2:
>  - fix wrong path in binding $id
>  - comment qcom,mdp4 node example (we don't want to validate it yet)
> Signed-off-by: David Heidelberg <david@ixit.cz>
> 
>  .../bindings/iommu/msm,iommu-v0.txt           | 64 ----------------
>  .../bindings/iommu/qcom,apq8064-iommu.yaml    | 76 +++++++++++++++++++
>  2 files changed, 76 insertions(+), 64 deletions(-)
>  delete mode 100644 Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
>  create mode 100644 Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt b/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
> deleted file mode 100644
> index 20236385f26e..000000000000
> --- a/Documentation/devicetree/bindings/iommu/msm,iommu-v0.txt
> +++ /dev/null
> @@ -1,64 +0,0 @@
> -* QCOM IOMMU
> -
> -The MSM IOMMU is an implementation compatible with the ARM VMSA short
> -descriptor page tables. It provides address translation for bus masters outside
> -of the CPU, each connected to the IOMMU through a port called micro-TLB.
> -
> -Required Properties:
> -
> -  - compatible: Must contain "qcom,apq8064-iommu".
> -  - reg: Base address and size of the IOMMU registers.
> -  - interrupts: Specifiers for the MMU fault interrupts. For instances that
> -    support secure mode two interrupts must be specified, for non-secure and
> -    secure mode, in that order. For instances that don't support secure mode a
> -    single interrupt must be specified.
> -  - #iommu-cells: The number of cells needed to specify the stream id. This
> -		  is always 1.
> -  - qcom,ncb:	  The total number of context banks in the IOMMU.
> -  - clocks	: List of clocks to be used during SMMU register access. See
> -		  Documentation/devicetree/bindings/clock/clock-bindings.txt
> -		  for information about the format. For each clock specified
> -		  here, there must be a corresponding entry in clock-names
> -		  (see below).
> -
> -  - clock-names	: List of clock names corresponding to the clocks specified in
> -		  the "clocks" property (above).
> -		  Should be "smmu_pclk" for specifying the interface clock
> -		  required for iommu's register accesses.
> -		  Should be "smmu_clk" for specifying the functional clock
> -		  required by iommu for bus accesses.
> -
> -Each bus master connected to an IOMMU must reference the IOMMU in its device
> -node with the following property:
> -
> -  - iommus: A reference to the IOMMU in multiple cells. The first cell is a
> -	    phandle to the IOMMU and the second cell is the stream id.
> -	    A single master device can be connected to more than one iommu
> -	    and multiple contexts in each of the iommu. So multiple entries
> -	    are required to list all the iommus and the stream ids that the
> -	    master is connected to.
> -
> -Example: mdp iommu and its bus master
> -
> -                mdp_port0: iommu@7500000 {
> -			compatible = "qcom,apq8064-iommu";
> -			#iommu-cells = <1>;
> -			clock-names =
> -			    "smmu_pclk",
> -			    "smmu_clk";
> -			clocks =
> -			    <&mmcc SMMU_AHB_CLK>,
> -			    <&mmcc MDP_AXI_CLK>;
> -			reg = <0x07500000 0x100000>;
> -			interrupts =
> -			    <GIC_SPI 63 0>,
> -			    <GIC_SPI 64 0>;
> -			qcom,ncb = <2>;
> -		};
> -
> -		mdp: qcom,mdp@5100000 {
> -			compatible = "qcom,mdp";
> -			...
> -			iommus = <&mdp_port0 0
> -				  &mdp_port0 2>;
> -		};
> diff --git a/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml b/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
> new file mode 100644
> index 000000000000..b9a2d02ed2e6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iommu/qcom,apq8064-iommu.yaml
> @@ -0,0 +1,76 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +
> +$id: http://devicetree.org/schemas/iommu/qcom,apq8064-iommu.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm APQ8064 IOMMU
> +
> +maintainers:
> +  - Will Deacon <will@kernel.org>

This should be someone from QCom or that otherwise cares about this 
device.

> +
> +description:
> +  The MSM IOMMU is an implementation compatible with the ARM VMSA short
> +  descriptor page tables. It provides address translation for bus masters
> +  outside of the CPU, each connected to the IOMMU through a port called micro-TLB.
> +
> +properties:
> +  compatible:
> +    const: qcom,apq8064-iommu
> +
> +  clocks:
> +    items:
> +      - description: interface clock for register accesses
> +      - description: functional clock for bus accesses
> +
> +  clock-names:
> +    items:
> +      - const: smmu_pclk
> +      - const: iommu_clk
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    description: Specifiers for the MMU fault interrupts.
> +    minItems: 1
> +    items:
> +      - description: non-secure mode interrupt
> +      - description: secure mode interrupt (for instances which supports it)
> +
> +  "#iommu-cells":
> +    const: 1
> +    description: Each IOMMU specifier describes a single Stream ID.
> +
> +  qcom,ncb:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: The total number of context banks in the IOMMU.

Is there a maximum? I assume it is not 2^32.

> +
> +required:
> +  - reg
> +  - interrupts
> +  - clocks
> +  - clock-names
> +  - qcom,ncb
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/clock/qcom,mmcc-msm8960.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +
> +    iommu@7500000 {
> +            compatible = "qcom,apq8064-iommu";
> +            reg = <0x07500000 0x100000>;
> +            interrupts = <GIC_SPI 63 IRQ_TYPE_LEVEL_HIGH>,
> +                         <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
> +            clocks = <&clk SMMU_AHB_CLK>,
> +                     <&clk MDP_AXI_CLK>;
> +            clock-names = "smmu_pclk",
> +                          "iommu_clk";
> +            #iommu-cells = <1>;
> +            qcom,ncb = <2>;
> +    };
> -- 
> 2.43.0
>