Vendor Car

Generate VSS based OEM VHAL

The following will show how to generate OEM VHAL sources from VSS tree using VSS Tools.

Prerequisites

The below example assumes ANDROID_BUILD_TOP environment variable. Run the following commands to set ANDROID_BUILD_TOP:

cd <aosp_workspace>
source build/envsetup.sh
lunch sdk_car_x86_64-trunk_staging-userdebug

To get the latest vss-tools-*.whl clone vss-tools, then run the command:

# within cloned vss-tools
uv build # This will build the vss_tools-*.whl file under dist/
cp dist/vss_tools-*.whl <aosp_workspace>/vendor/car/tools/vss_tools/

or use the sources:

# within cloned vss-tools
python -m venv .venv
source .venv/bin/activate

For further information see: https://github.com/COVESA/vss-tools?tab=readme-ov-file#installation

Generating VSS based code

To (re-)generate VSS based AOSP sources run:

vspec export vhal --no-extend-new \
  --vspec path/to/vehicle_signal_specification/spec/VehicleSignalSpecification.vspec \
  --vhal-map $ANDROID_BUILD_TOP/device/generic/car/emulator/vhalmap/value_map.json \ 
  --aosp-workspace-path $ANDROID_BUILD_TOP

This will (re-)generate the following files:

<aosp_workspace>/device/generic/car/emulator/vhalmap/value_map.json
<aosp_workspace>/vendor/car/packages/services/Oem/oem-service/AndroidManifest.xml
<aosp_workspace>/vendor/car/packages/services/Oem/oem-service/res/values/strings.xml
<aosp_workspace>/vendor/car/packages/services/Car/car-lib/src/android/car/oem/OemPermissions.java
<aosp_workspace>/vendor/car/packages/services/Car/car-lib/src/android/car/oem/VehiclePropertyIdsOem.java
<aosp_workspace>/vendor/car/hardware/interfaces/automotive/vehicle/aidl_property/vendor/android/hardware/automotive/vehicle/VehiclePropertyOem.aidl

Generating annotation enums (post processing)

Running hardware/interfaces/automotive/vehicle/tools/generate_annotation_enums.py

python $ANDROID_BUILD_TOP/hardware/interfaces/automotive/vehicle/tools/generate_annotation_enums.py
cd $ANDROID_BUILD_TOP/hardware/interfaces/automotive/vehicle/
# Revert changes made by generate_annotation_enums.py to the Java files.
# These two files are used only by fakevhal, which is not used here.
# They contain a map with more than 1,400 entries, which exceeds the JVM bytecode size limit.
# This causes the runtime error "Cannot load updatable package code" when CarService starts.
git restore aidl/generated_lib/4/java/AccessForVehicleProperty.java
git restore aidl/generated_lib/4/java/ChangeModeForVehicleProperty.java

This will update the following files:

<aosp_workspace>/hardware/interfaces/automotive/vehicle/aidl/generated_lib/4/cpp/AccessForVehicleProperty.h
<aosp_workspace>/hardware/interfaces/automotive/vehicle/aidl/generated_lib/4/cpp/ChangeModeForVehicleProperty.h
<aosp_workspace>/hardware/interfaces/automotive/vehicle/aidl/generated_lib/4/cpp/VersionForVehicleProperty.h

VehiclePropertyIdsParser (post processing)

Running packages/services/Car/tools/vehiclepropertyidsparser/prebuilt/VehiclePropertyIdsParser.jar:

java -jar $ANDROID_BUILD_TOP/packages/services/Car/tools/vehiclepropertyidsparser/prebuilt/VehiclePropertyIdsParser.jar \
  $ANDROID_BUILD_TOP/packages/services/Car/car-lib/src \
  $ANDROID_BUILD_TOP/vendor/car/packages/services/Car/car-lib/src \
  $ANDROID_BUILD_TOP/packages/services/Car/car-lib/generated-prop-config/CarSvcProps.json

This will (re-) generate:

<aosp_workspace>/packages/services/Car/car-lib/generated-prop-config/CarSvcProps.json