HAL Feature Profile (HFP)

The HAL Feature Profile (HFP) is a YAML-based declaration provided by OEMs to define the capabilities of their vendor layer implementation. It serves critical functions:

• Test Driver Configuration: Enables the vendor test suite to perform targeted testing based on the declared feature set.
• Capability Declaration: Provides a comprehensive list of supported HAL features for verification against product requirements.

Each HAL component defines its own hfp_xxx.yaml within the vendor layer deliverables, typically located in a configuration directory (e.g., vendor/<vendor_name>/<platform>/config/).

File Syntax and Schema

The HFP utilizes YAML syntax for structured data representation, this is an example format the actual format is defined with the components.

hal:
  profile: "TV" # Profile Type
  platform: "Sky Glass" # Platform Identifier
  schema_version: "1.2.0" # HFP Schema Version

  components:
    kernel:
      version: "5.15.164"

    av_buffer:
      non_secure_heap_bytes: 1048576 # 1MB
      secure_heap_bytes: 524288 # 512KB

    video_decoder:
      resources:
        - id: 0
          codecs: ["H264", "HEVC"]
          max_resolution: "4K"
          max_fps: 60
          bit_depth: 10
        - id: 1
          codecs: ["MPEG2", "AV1"]
          max_resolution: "1080p"
          max_fps: 30
          bit_depth: 8

    cdm:
      mandatory: true
      resources:
        PlayReady:
          version: "4.4"
          mandatory: true
          secure_storage: true
          concurrent_sessions: 2
        WideVine:
          version: "L3"
          mandatory: false
          secure_storage: false
          concurrent_sessions: 1
        FairPlay:
          version: "4.0"
          mandatory: false

    audio_decoder:
      supported_formats: ["AAC", "MP3", "AC3", "DTS", "Dolby Digital"]
      max_channels: 8
      sample_rate: 192000

    tuner:
      type: "dvb-c"
      frequency_range: "50-860 MHz"
      modulation: ["QAM16", "QAM64", "QAM256"]
      bandwidth: 8

    display:
      resolution: "1920x1080"
      hdr_support: true
      interfaces: ["HDMI", "DisplayPort"]
      refresh_rate: 60
      color_space: "BT.2020"

    network:
      interfaces: ["Ethernet", "WiFi"]
      wifi_standards: ["802.11a", "802.11b", "802.11g", "802.11n", "802.11ac", "802.11ax"]
      ethernet_speed: "1Gbps"
      ipv6_support: true

    bluetooth:
      version: "5.2"
      profiles: ["A2DP", "HFP", "AVRCP", "BLE"]
      le_coded_phy: true

    input:
      devices:
        - name: "Remote Control"
          types: ["IR", "Bluetooth", "RF4CE"]
          features: ["Voice Control", "Navigation"]
        - name: "Keyboard"
          types: ["Bluetooth"]
          features: ["Text Input"]

    camera:
      resolution: "1920x1080"
      fps: 30
      auto_focus: true
      hdr: true

    mic:
      channels: 2
      noise_cancellation: true
      echo_cancellation: true

    graphics_compositor:
      layers: 4
      alpha_blending: true
      scaling: true
      rotation: true

    power_management:
      states: ["On", "Standby", "Deep Sleep"]
      wake_sources: ["Remote", "Network", "Timer"]
      power_consumption:
        standby: "0.5W"
        deep_sleep: "0.1W"

    telemetry:
      supported_metrics: ["CPU Usage", "Memory Usage", "Network Throughput", "Temperature"]
      reporting_interval: 60 # seconds
      logging_levels: ["Error", "Warning", "Info", "Debug"]

    drm_session_management:
      max_concurrent_sessions: 4
      secure_storage_types: ["TEE", "Secure Flash"]
      persistent_sessions: true

Mandatory and Optional HALs and Features

The HFP explicitly lists all supported HAL components. Components or specific features within them can be marked as mandatory to indicate their requirement status. Any field not defined can be assumed to be false but for clarity can also be stated e.g. mandatory: false.

hal:
  components:
    cdm:
      mandatory: true
      resources:
        PlayReady:
          version: "4.4"
          mandatory: true
        WideVine:
          version: "L3"
          mandatory: false

HFP Versioning

The schema_version field adheres to semantic versioning (major.minor.patch) to ensure backward compatibility as the HFP schema evolves.

Tooling

Dedicated tools are essential for creating and validating the HFP will be created:

• Schema Validation: Implements robust validation against a defined schema (e.g., JSON Schema).
• HFP Generator: Tool to help create HFP files.