Files
hardware_interfaces/audio
Mikhail Naganov d21b0e7e55 audio: Simplify and extend alsa::Mixer
Remove alsa::MixerControl. tinyALSA contains utility
functions for setting values in percents, they use
the same logic as used to be there for handling
the "volume" control. Use access serialization at
the mixer level, rather than for each control.

Move the call to 'mixer_open' to alsa::Mixer.

Add controls for capture (mic) mute and gain. They
will be used by the primary HAL.

Bug: 264712385
Test: atest VtsHalAudioCoreTargetTest
Change-Id: I0fad994153de96aceec3eb8f2fec19805ec912f8
(cherry picked from commit f12d4a1ef8)
Merged-In: I0fad994153de96aceec3eb8f2fec19805ec912f8
2023-08-01 14:31:01 -07:00
..
2022-12-29 23:22:02 +00:00
2022-12-29 23:22:02 +00:00

Audio HAL

Directory structure of the audio HAL related code.

Directory Structure for AIDL audio HAL

The AIDL version is located inside aidl directory. The tree below explains the role of each subdirectory:

  • aidl_api — snapshots of the API created each Android release. Every release, the current version of the API becomes "frozen" and gets assigned the next version number. If the API needs further modifications, they are made on the "current" version. After making modifications, run m <package name>-update-api to update the snapshot of the "current" version.
  • android/hardware/audio/common — data structures and interfaces shared between various HALs: BT HAL, core and effects audio HALs.
  • android/hardware/audio/core — data structures and interfaces of the core audio HAL.
  • default — the default, reference implementation of the audio HAL service.
  • vts — VTS tests for the AIDL HAL.

Directory Structure for HIDL audio HAL

Run common/all-versions/copyHAL.sh to create a new version of the HIDL audio HAL based on an existing one. Note that this isn't possible since Android T release. Android U and above uses AIDL audio HAL.

  • 2.0 — version 2.0 of the core HIDL API. Note that .hal files can not be moved into the core directory because that would change its namespace and include path.
    • config — the XSD schema for the Audio Policy Manager configuration file.
  • 4.0 — version 4.0 of the core HIDL API.
  • ...
  • common — common types for audio core and effect HIDL API.
    • 2.0 — version 2.0 of the common types HIDL API.
    • 4.0 — version 4.0.
    • ...
    • 7.0 — version 7.0.
      • example — example implementation of the core and effect V7.0 API. It represents a "fake" audio HAL that doesn't actually communicate with hardware.
    • all-versions — code common to all version of both core and effect API.
      • default — shared code of the default implementation.
        • service — vendor HAL service for hosting the default implementation.
      • test — utilities used by tests.
      • util — utilities used by both implementation and tests.
  • core — VTS tests and the default implementation of the core API (not HIDL API, it's in audio/N.M).
    • 7.0 — code specific to version V7.0 of the core HIDL API
    • all-versions — the code is common between all versions, version-specific parts are enclosed into conditional directives of preprocessor or reside in dedicated files.
      • default — code that wraps the legacy API (from hardware/libhardware).
        • util — utilities for the default implementation.
      • vts VTS tests for the core HIDL API.
  • effect — same for the effect HIDL API.
    • 2.0
      • config — the XSD schema for the Audio Effects configuration file.
    • 4.0
    • ...
    • all-versions
      • default — code that wraps the legacy API (from hardware/libhardware).
        • util — utilities for the default implementation.
      • vts VTS tests for the effect HIDL API.
  • policy — Configurable Audio Policy schemes.
    • 1.0 — note that versions of CAP are not linked to the versions of audio HAL.
      • vts — VTS tests for validating actual configuration files.
      • xml — XSD schemas for CAP configuration files.