（1）架构介绍

（A）Camera的框架分为Kernel部分和Hal部分

Kernel部分：

• image sensor driver——负责具体型号的sensor的id检测，上电，以及在preview、capture、初始化、3A等等功能设定时的寄存器配置；
• ISP driver——通过DMA将sensor数据流上传；

Hal部分：

• imageio——主要负责数据buffer上传的pipe；
• drv——包含imgsensor和isp的hal层控制；
• feature io——包含各种3A等性能配置；

来看一张图，大致来了解一下Camera的整体架构。

（B）MiddleWare(MW)层

• ICameraProvider——向上暴露的接口调用，实现是在CameraProvider中；
• [email protected]——用于Camera Service去操作各个Camera device的操作，实现在CameraDevice3中；
• [email protected]——Camera会话的接口；
• ICameraDeviceCallBack——底层对上层的CallBack接口；
• CameraDeviceManager——用于管理CameraDevice，包括查找，打开，关闭等。

（C）Pipeline介绍

PipelineModel是HAL3核心架构，对上需要开放对Pipeline创建 / 操作的API，对下需要建立Pipeline / 管理Pipeline的生命周期。
PipelineModel会针对不同的场景创建不同的Pipeline和HWNode，HWNode向下传输APP层的命令，向上传递图形数据。

• P1Node——pipeline的root node，input app命令，output raw data to P2CaptureNode and P2StreamNode；
• P2CaptureNode——转换raw data to yuv，Support scale/crop；
• P2StreamingNode——和P2CaptureNode功能类似；
• JPEGNode——Convert YUV to Jpeg；
• FDNode——Generate the FD information；

（2）Camera Open流程（Hal-Sensor）

在APP层调用openCamera后会调用的CameraDevice层，最后调用到driver中，整体的调用流程如下：

先从CameraDevice3SessionImpl的open函数分析。

//vendor/mediatek/proprietary/hardware/mtkcam3/main/hal/device/3.x/device/CameraDevice3SessionImpl.cpp

auto ThisNamespace::open(
    const ::android::sp<V3_4::ICameraDeviceCallback>& callback) -> ::android::status_t
{
    
    auto pDeviceManager = mStaticInfo.mDeviceManager;
    auto const& instanceName = mStaticInfo.mStaticDeviceInfo->mInstanceName;
     
    status = pDeviceManager->startOpenDevice(instanceName);
     
    err = onOpenLocked(callback);
    pDeviceManager->updatePowerOnDone();
    status = pDeviceManager->finishOpenDevice(instanceName, false/*cancel*/);
}
     
auto ThisNamespace::onOpenLocked(
    const ::android::sp<V3_4::ICameraDeviceCallback>& callback
) -> ::android::status_t
{
    
    //--------------------------------------------------------------------------
    {
    
        Mutex::Autolock _l(mPipelineModelLock);
        auto pPipelineModelMgr = IPipelineModelManager::get();
        auto pPipelineModel = pPipelineModelMgr->getPipelineModel( getInstanceId() );
        ::android::status_t err = OK;
        err = pPipelineModel->open(getInstanceName().c_str(), this);
        mPipelineModel = pPipelineModel;
    }
    //--------------------------------------------------------------------------
    return OK;
}

//vendor/mediatek/proprietary/hardware/mtkcam3/pipeline/model/PipelineModelImpl.cpp

auto PipelineModelImpl::open(
    std::string const& userName,
    android::wp<IPipelineModelCallback> const& callback) -> int
{
    
    {
    
        std::lock_guard<std::timed_mutex> _l(mLock);
        mUserName = userName;
        mCallback = callback;
        mvOpenFutures.push_back(
            std::async(std::launch::async,
                [this]() {
    
                    return CC_LIKELY( mHalDeviceAdapter!=nullptr )
                        && CC_LIKELY( mHalDeviceAdapter->open() ) 
                        //android::sp<IHalDeviceAdapter> const    mHalDeviceAdapter;
                        && CC_LIKELY( mHalDeviceAdapter->powerOn() );
                }
            )
        ); 
    }
    return OK;
}

调用mHalDeviceAdapter的open用于初始化DeviceAdapter，这里重点看powerOn函数，这里的powerOn有另起一个线程去操作sensor，等待sensor上电完成后对3A进行powerOn操作。

//vendor/mediatek/proprietary/hardware/mtkcam3/pipeline/model/adapter/HalDeviceAdapter.cpp

virtual auto powerOn() -> bool override
{
    
    //1.调用HalSensor的powerOn
    std::future<bool> future_initSensor =
        std::async(std::launch::async,
            [ this ]() {
    
                    if (CC_UNLIKELY( !mvHalSensor[i]->powerOn(mName.c_str(), 1, &sensorIndex) ))
        }
     
    //2.init 3A and poweron 3A
    bool success_sensorPowerOn = false;
    bool success_init3A = true;
    for (size_t i = 0; i < mvPhySensorId.size(); i++)
    {
    
        mvHal3A.push_back(IHal3AAdapter::create(mvPhySensorId[i], mName.c_str()));
        mvHalIsp.push_back(MAKE_HalISP(mvPhySensorId[i], mName.c_str()));
    }
     
    //3.Wait for Sensor PowerOn
    {
    
        success_sensorPowerOn = future_initSensor.get();
        if  ( ! success_sensorPowerOn ) {
    
            return false;
        }
    }
        
    //4.Notify 3A of Power On
    for (size_t i = 0; i < mvHal3A.size(); i++){
    
       if (mvHal3A[i] != nullptr){
    
           mvHal3A[i]->notifyPowerOn();
        }
    }
}

这里继续跟踪mvHalSensor[i]->powerOn，会调用到HalSensor.cpp中，这里到了和Driver交互的部分：

• 初始化SeninfDrv和SensorDrv；
• setSensorMclk和setSensorMclkDrivingCurrent；
• 最后通过mpSensorDrv->open；

//vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensor.cpp
MBOOL HalSensor:: powerOn(){
    
     
    mpSeninfDrv->init();
    mpSensorDrv->init();
    for (MUINT i = 0; i < uCountOfIndex; i++)
    {
    
        setSensorMclk(sensorIdx, 1)
        setSensorMclkDrivingCurrent(sensorIdx)
     
        // Open sensor, try to open 3 time
        for (int i =0; i < 3; i++) {
    
            if ((ret = mpSensorDrv->open(sensorIdx)) != SENSOR_NO_ERROR) {
    
                MY_LOGE("pSensorDrv->open fail, retry = %d ", i);
            }
        }
    }
}

接下来会调用到imgsensor_drv的open函数，到此featureControl调用到驱动的SENSOR_FEATURE_OPEN。

//vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/imgsensor_drv.cpp
MINT32
ImgSensorDrv::open(IMGSENSOR_SENSOR_IDX sensorIdx)
{
    
    MUINT32                           featureParaLen = sizeof(MUINT32);
    MUINT32                           featurePara;

    return featureControl(sensorIdx, SENSOR_FEATURE_OPEN, (MUINT8 *)&featurePara, &featureParaLen);
}

MINT32  ImgSensorDrv::featureControl(
    IMGSENSOR_SENSOR_IDX sensorIdx,
    ACDK_SENSOR_FEATURE_ENUM FeatureId,
    MUINT8 *pFeaturePara,
    MUINT32 *pFeatureParaLen
)
{
    

	ACDK_SENSOR_FEATURECONTROL_STRUCT featureCtrl;
	
    //结构ACDK_SENSOR_FEATURECONTROL_STRUCT和kernel中一致
    featureCtrl.InvokeCamera = sensorIdx;
    featureCtrl.FeatureId = FeatureId;//SENSOR_FEATURE_SET_DRIVER
    featureCtrl.pFeaturePara = pFeaturePara;
    featureCtrl.pFeatureParaLen = pFeatureParaLen;
    	
    if (ioctl(m_fdSensor, KDIMGSENSORIOC_X_FEATURECONCTROL , &featureCtrl) < 0) {
    
    	LOG_ERR("[featureControl] Err-ctrlCode (%s)", strerror(errno));
        return -errno;
    }
  	
    return SENSOR_NO_ERROR;
}

（3）Sensor Search流程

CameraService是在开机时启动的，启动后进行searchSensor的操作，会search系统有多少camera，开机时的search操作，只进行camera支持数量的遍历，以及sensor ID的读取操作。

HalSensorList：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.enumList.cpp
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.cpp

SeninfDrv：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/mt6765/seninf_drv.cpp

SensorDrv：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/imgsensor_drv.cpp

//vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.cpp

MUINT
HalSensorList::
searchSensors()
{
    
    Mutex::Autolock _l(mEnumSensorMutex);

    MY_LOGD("searchSensors");
    return  enumerateSensor_Locked();
}

MUINT
HalSensorList::
queryNumberOfSensors() const
{
    
    Mutex::Autolock _l(mEnumSensorMutex);

    return  mEnumSensorList.size();
}

IMetadata const&
HalSensorList::
queryStaticInfo(MUINT const index) const
{
    
    EnumInfo const* pInfo = queryEnumInfoByIndex(index);
    MY_LOGF_IF(pInfo==NULL, "NULL EnumInfo for sensor %d", index);

    return  pInfo->mMetadata;
}

searchSensors()会调用enumerateSensor_Locked()。

//vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/HalSensorList.enumList.cpp

MUINT HalSensorList::enumerateSensor_Locked()
{
    
    SensorDrv *const pSensorDrv = SensorDrv::get();
    SeninfDrv *const pSeninfDrv = SeninfDrv::createInstance();
    //初始化seninf,配置ISP相关内容
    pSeninfDrv->init();
     
    //将所有的clk全部打开
    pSeninfDrv->setAllMclkOnOff(ISP_DRIVING_8MA, TRUE);
        
    pSensorDrv->init();
    for (MUINT i = IMGSENSOR_SENSOR_IDX_MIN_NUM; i <= max_index_of_camera; i++) {
    
        if((ret = pSensorDrv->searchSensor((IMGSENSOR_SENSOR_IDX)i)) == SENSOR_NO_ERROR){
    
            //query sensorinfo
           querySensorDrvInfo((IMGSENSOR_SENSOR_IDX)i);
           //fill in metadata
           buildSensorMetadata((IMGSENSOR_SENSOR_IDX)i);
           pSensorInfo = pSensorDrv->getSensorInfo((IMGSENSOR_SENSOR_IDX)i);
           addAndInitSensorEnumInfo_Locked(
                (IMGSENSOR_SENSOR_IDX)i,
                mapToSensorType(pSensorInfo->GetType()),
                pSensorInfo->getDrvMacroName());
        }
    }     
}

下面看下pSensorDrv->getSensorInfo的流程，这里有去获取sensorList的内容。

//vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/common/v1/imgsensor_drv.cpp
MINT32 ImgSensorDrv::searchSensor(IMGSENSOR_SENSOR_IDX sensorIdx)
{
    
    GetSensorInitFuncList(&pSensorInitFunc);
     
    featureControl(sensorIdx, SENSOR_FEATURE_SET_DRIVER, (MUINT8 *)&idx, &featureParaLen);
     
    NSFeature::SensorInfoBase* pSensorInfo = pSensorInitFunc[idx].pSensorInfo;
}

（A）GetSensorInitFuncList是获取到配置的sensorList的内容，此sensorList需要与kernel层配置的一致，不一致的话在打开camera时会出现异常。

//vendor/mediatek/proprietary/custom/mtxxxx/hal/imgsensor_src/sensorlist.cpp

MSDK_SENSOR_INIT_FUNCTION_STRUCT SensorList[] =
{
    
/*IMX*/
#if defined(IMX586_MIPI_RAW)
    RAW_INFO_M(IMX586_SENSOR_ID, DEFAULT_MODULE_INDEX, DEFAULT_MODULE_ID, SENSOR_DRVNAME_IMX586_MIPI_RAW, CAM_CALGetCalData),
#endif
#if defined(IMX519_MIPI_RAW)
    RAW_INFO_M(IMX519_SENSOR_ID, DEFAULT_MODULE_INDEX, DEFAULT_MODULE_ID, SENSOR_DRVNAME_IMX519_MIPI_RAW, CAM_CALGetCalData),
#endif
//...
};

UINT32 GetSensorInitFuncList(MSDK_SENSOR_INIT_FUNCTION_STRUCT **ppSensorList)
{
    
    if (NULL == ppSensorList) {
    
        ALOGE("ERROR: NULL pSensorList\n");
        return MHAL_UNKNOWN_ERROR;
    }
    *ppSensorList = &SensorList[0];
	return MHAL_NO_ERROR;
}

（B）featureControl的setDriver流程同上面的一致。