aosp12/system/tools/hidl

hidl-gen

Full documentation can be found here: https://source.android.com/devices/architecture/hidl/

hidl-gen is a compiler for the HIDL (HAL Interface Design Language) which generates C++ and Java endpoints for RPC mechanisms. The main userspace libraries which this compiler uses can be found at system/libhidl.

1. Build

m hidl-gen

2. Run

Note that options for hidl-gen expected to be invoked by the build system are marked with 'internal' in the help menu.

hidl-gen -h

hidl-gen -o output -L c++-impl -r android.hardware:hardware/interfaces -r android.hidl:system/libhidl/transport android.hardware.nfc@1.0

Some defaults for package roots are also provided

hidl-gen -o output -L c++-impl android.hardware.nfc@1.0
hidl-gen -o output -L vts android.hardware.nfc@1.0
hidl-gen -L hash android.hardware.nfc@1.0

Example command for vendor project

hidl-gen -L c++-impl -r vendor.foo:vendor/foo/interfaces vendor.foo.nfc@1.0

See update-makefiles-helper.sh and update-all-google-makefiles.sh for examples of how to generate HIDL makefiles (using the -Landroidbp option).

NOTE: When using the -Landroidbp option, you can force generated modules to be installed in /system_ext rather than other partition by putting a marker file .hidl_for_system_ext alongside *.hal files.

NOTE: You can also install the vendor variant of the generated modules to be installed in /odm rather than /vendor by putting a marker file .hidl_for_odm alongside *.hal files.

c2hal

This is a helper tool to convert C headers to valid .hal files.

m c2hal && c2hal -h