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Date:   Wed, 14 Sep 2022 07:08:40 -0500
From:   Rob Herring <robh@kernel.org>
To:     Mikko Perttunen <cyndis@kapsi.fi>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        devicetree@vger.kernel.org, Sameer Pujar <spujar@nvidia.com>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Mikko Perttunen <mperttunen@nvidia.com>,
        linux-tegra@vger.kernel.org, Ashish Mhetre <amhetre@nvidia.com>
Subject: Re: [PATCH v2 3/8] dt-bindings: Add bindings for Tegra234 NVDEC
Message-ID: <20220914120840.GA1837218-robh@kernel.org>
References: <20220913131447.2877280-1-cyndis@kapsi.fi>
 <20220913131447.2877280-4-cyndis@kapsi.fi>
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On Tue, Sep 13, 2022 at 04:14:41PM +0300, Mikko Perttunen wrote:
> From: Mikko Perttunen <mperttunen@nvidia.com>
> 
> Update NVDEC bindings for Tegra234. This new engine version only has
> two memory clients, but now requires three clocks, and as a bigger
> change the engine loads firmware from a secure carveout configured by
> the bootloader.
> 
> For the latter, we need to add a phandle to the memory controller
> to query the location of this carveout, and several other properties
> containing offsets into the firmware inside the carveout. These
> properties are intended to be populated through a device tree overlay
> configured at flashing time, so that the values correspond to the
> flashed NVDEC firmware.
> 
> As the binding was getting large with many conditional properties,
> also split the Tegra234 version out into a separate file.
> 
> Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
> ---
> v2:
> - Split out into separate file to avoid complexity with
>   conditionals etc.
> ---
>  .../gpu/host1x/nvidia,tegra234-nvdec.yaml     | 154 ++++++++++++++++++
>  1 file changed, 154 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpu/host1x/nvidia,tegra234-nvdec.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpu/host1x/nvidia,tegra234-nvdec.yaml b/Documentation/devicetree/bindings/gpu/host1x/nvidia,tegra234-nvdec.yaml
> new file mode 100644
> index 000000000000..eab0475ca983
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpu/host1x/nvidia,tegra234-nvdec.yaml
> @@ -0,0 +1,154 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/gpu/host1x/nvidia,tegra234-nvdec.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Device tree binding for NVIDIA Tegra234 NVDEC
> +
> +description: |
> +  NVDEC is the hardware video decoder present on NVIDIA Tegra210
> +  and newer chips. It is located on the Host1x bus and typically
> +  programmed through Host1x channels.
> +
> +maintainers:
> +  - Thierry Reding <treding@gmail.com>
> +  - Mikko Perttunen <mperttunen@nvidia.com>
> +
> +properties:
> +  $nodename:
> +    pattern: "^nvdec@[0-9a-f]*$"
> +
> +  compatible:
> +    enum:
> +      - nvidia,tegra234-nvdec
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 3
> +
> +  clock-names:
> +    items:
> +      - const: nvdec
> +      - const: fuse
> +      - const: tsec_pka
> +
> +  resets:
> +    maxItems: 1
> +
> +  reset-names:
> +    items:
> +      - const: nvdec
> +
> +  power-domains:
> +    maxItems: 1
> +
> +  iommus:
> +    maxItems: 1
> +
> +  dma-coherent: true
> +
> +  interconnects:
> +    items:
> +      - description: DMA read memory client
> +      - description: DMA write memory client
> +
> +  interconnect-names:
> +    items:
> +      - const: dma-mem
> +      - const: write
> +
> +  nvidia,memory-controller:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      phandle to the memory controller for determining carveout information.
> +
> +  nvidia,bl-manifest-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to bootloader manifest from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.
> +
> +  nvidia,bl-code-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to bootloader code section from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.
> +
> +  nvidia,bl-data-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to bootloader data section from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.
> +
> +  nvidia,os-manifest-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to operating system manifest from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.
> +
> +  nvidia,os-code-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to operating system code section from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.
> +
> +  nvidia,os-data-offset:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description:
> +      Offset to operating system data section from beginning of firmware. Typically set as
> +      part of a device tree overlay corresponding to flashed firmware.

I don't think DT is the place for describing your runtime loaded 
firmware layout.

Rob