Add documentation to describe device tree bindings for QCOM's platform-parts-info node. Firmware populates these nodes to pass the information to kernel regarding the subset of hardware blocks and features like Camera, Modem, Display present in a product. This is to support that the same software image runs seamlessly on different platforms where one or more HW blocks are not supported or if some sub parts for a particular block are not supported. Purpose of these definitions is to allow clients to know about this, and thus, handle these cases gracefully. For eg: Camera drivers and user space daemons can use this to know if camera is not supported on the device, or some particular HW blocks inside a camera are not supported. Signed-off-by: Naman Jain <quic_namajain@xxxxxxxxxxx> --- .../firmware/qcom,platform-parts-info.yaml | 88 +++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 Documentation/devicetree/bindings/firmware/qcom,platform-parts-info.yaml diff --git a/Documentation/devicetree/bindings/firmware/qcom,platform-parts-info.yaml b/Documentation/devicetree/bindings/firmware/qcom,platform-parts-info.yaml new file mode 100644 index 000000000000..64e085d3ea88 --- /dev/null +++ b/Documentation/devicetree/bindings/firmware/qcom,platform-parts-info.yaml @@ -0,0 +1,88 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/firmware/qcom,platform-parts-info.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: QCOM Platform's Parts Information + +description: + Qualcomm platforms support a feature where a subset of hardware blocks + like Camera, GPU, Display, Modem, CPUs are available in a product, + based on features selected for a particular Stock keeping unit (SKU) + and the same software images are supposed to work seamlessly with these. + This is to support usecases where lets say a software image running on handset + device which supports display and camera, can work just fine on another + IoT product which doesn't need these. This also enables usecases, where certain + sub parts for a HW block are not supported. + + Firmware (bootloader), reads the parts related information from lower + layers and passes this information to kernel via this device tree interface, + so that the respective clients are aware of it. + For example, Camera drivers and its user space daemons can use this interface + to know if camera is not supported on the device or if certain sub feature inside + camera is not supported. + +maintainers: + - Naman Jain <quic_namajain@xxxxxxxxxxx> + +properties: + $nodename: + const: qcom,platform-parts-info + + qcom,subset-parts-names: + description: + List of part name strings, sorted in same order as the subset-parts property. + Parts here can be modem, camera, display etc. which are either partially supported + or not supported at all. + $ref: /schemas/types.yaml#/definitions/string-array + minItems: 1 + maxItems: 13 + items: + enum: [gpu, video, camera, display, audio, wlan, compute, sensors, npu, spss, nav, nsp, eva] + + qcom,subset-parts: + description: + A matrix, with each row corresponding to a specific part type (GPU, Camera etc) mentioned + in subset-parts-names property. The number of rows here are expected to be same as number of + subset-parts-names provided. A row can contain multiple bitmask values representing + multiple parts of the same type, if supported on a platform, like 2 display panels, or + 3 cameras for example. + Each bitmask value, has its 0th bit set if that part is completely not supported. + Otherwise, rest of the bits will correspond to specific functionalities + of that part not supported. + If the bitmask is 0xffff, i.e. all bits set, then that value is invalid and not to be + considered. + $ref: /schemas/types.yaml#/definitions/uint32-matrix + minItems: 1 + maxItems: 13 + items: + maxItems: 3 + items: + description: + Bitmask value corresponding to a part of a specific part type, or 0xffff if data is + invalid and not to be considered. + + qcom,subset-cores: + description: + A bitmask value, encoded from LSB with a set bit corresponding to actual physical CPU + not supported on the SoC. + $ref: /schemas/types.yaml#/definitions/uint32 + +required: + - qcom,subset-cores + +additionalProperties: false + +examples: + - | + firmware { + qcom,platform-parts-info { /* populated by firmware */ + qcom,subset-parts-names = "gpu", "display", "camera"; + qcom,subset-parts = <0x1 0xffff 0xffff>, /* GPU 1 is completely not supported */ + <0x0 0x1 0xffff>, /* Display 2 is fully not supported */ + <0x30 0xffff 0xffff>; /* Camera 1 is partially supported */ + qcom,subset-cores = <0x90>; /* CPU 4 and 7 are not supported */ + }; + }; +... -- 2.17.1
