What is HAL?
The Hardware Abstraction Layer (HAL) in Android provides a standard interface for hardware vendors to implement, allowing Android OS to communicate with device hardware without knowing the hardware specifics. HAL modules act as a bridge between the Android system and hardware drivers.
Role in Android
- Enables Android to support a wide range of hardware with minimal changes to the OS.
- Vendors implement HAL modules for their hardware, which the Android system calls via defined interfaces.
- Ensures modularity and easier updates for both hardware and software.
Architecture
HAL sits between the Android Framework and the Linux kernel drivers. The typical stack is:
Android App
Android Framework
JNI (Java Native Interface)
HAL
Linux Kernel Driver
Hardware
Examples of HAL Modules
Camera HAL
Manages camera hardware interfaces and image processing.
Audio HAL
Handles audio input/output and audio processing.
Bluetooth HAL
Manages Bluetooth connectivity and protocols.
Wi-Fi HAL
Controls Wi-Fi hardware and network management.
Sensor HAL
Manages various device sensors (accelerometer, gyroscope, etc.).
Learn More
Explore the official Android HAL documentation for detailed implementation guides.
Official Documentation