VehicleHal.java - fwk层对应VehicleService

android12-release
【IVI】VehicleService启动
【IVI】车载设备硬件抽象层VHAL
【IVI】CarService启动

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1、VehicleHal.java初始化

• CarService： 位于 /platform/packages/services/Car/。

1. 流程主要有两个，一是创建CarService.java#onCreate() -> ICarImpl.java#new -> VehicleHal.java#new，而是初始化CarService.java#onCreate() -> ICarImpl.java#init -> VehicleHal.java#init
2. android.hardware.automotive.vehicle.V2_0.IVehicle.getService(instanceName)获取底层服务VehicleService.cpp/IVehicle.hal
   
3. VehicleHal.java创建初始化，此类处理与本机HAL的接口，并对接收的数据进行基本解析（类型检查）。然后将每个事件发送到相应的HalServiceBase实现。HalServiceBase负责将数据转换为相应的Car*Service和Car*Manager API。
   

1.1 hal服务区分

1.2 简要时序图

2、PowerHalService为例

2.1 PowerHalService初始化和订阅

• VehicleHal.java#init -> PowerHalService#init订阅最终调用到mVehicle.subscribe()，并注册监听回调IVehicleCallback即VehicleHal extends IVehicleCallback.Stub
  
• IVehicleCallback.hal#onPropertyEvent -> VehicleHal.java#onPropertyEvent -> PowerHalService.java#onHalEvents -> PowerEventListener 属性监听最终传递给APP等注册的监听PowerEventListener
  

private void dispatchEvents(List<VehiclePropValue> values, PowerEventListener listener) {
    for (VehiclePropValue v : values) {
        switch (v.prop) {
            case AP_POWER_STATE_REPORT:
                // Ignore this property event. It was generated inside of CarService.
                break;
            case AP_POWER_STATE_REQ:
                int state = v.value.int32Values.get(VehicleApPowerStateReqIndex.STATE);
                int param = v.value.int32Values.get(VehicleApPowerStateReqIndex.ADDITIONAL);
                Slog.i(CarLog.TAG_POWER, "Received AP_POWER_STATE_REQ="
                        + powerStateReqName(state) + " param=" + param);
                listener.onApPowerStateChange(new PowerState(state, param));
                break;
            case DISPLAY_BRIGHTNESS:
            {
                int maxBrightness;
                synchronized (mLock) {
                    maxBrightness = mMaxDisplayBrightness;
                }
                int brightness = v.value.int32Values.get(0) * MAX_BRIGHTNESS / maxBrightness;
                if (brightness < 0) {
                    Slog.e(CarLog.TAG_POWER, "invalid brightness: " + brightness
                            + ", set to 0");
                    brightness = 0;
                } else if (brightness > MAX_BRIGHTNESS) {
                    Slog.e(CarLog.TAG_POWER, "invalid brightness: " + brightness + ", set to "
                            + MAX_BRIGHTNESS);
                    brightness = MAX_BRIGHTNESS;
                }
                Slog.i(CarLog.TAG_POWER, "Received DISPLAY_BRIGHTNESS=" + brightness);
                listener.onDisplayBrightnessChange(brightness);
            }
                break;
        }
    }
}
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2.2 简要时序图