一、整體介紹

首先看下mtkcam的整體框架圖如下包含了很多的內(nèi)容，其中camera的打開流程也貫穿在其中，從Camera APK 一層層的系統(tǒng)調(diào)用到driver再到Hardware層，這篇文章主要從Pipeline開始介紹打開camera的流程，JAVA/Cameraservice/MiddleWare層后續(xù)再進行介紹：

1、MiddleWare(MW)層介紹

ICameraProvider：向上暴露的接口調(diào)用，實現(xiàn)是在CameraProverideer中；
[email protected]：用于Camera Service去操作各個Camera device的操作，實現(xiàn)在CameraDevice3中；
[email protected]： Camera會話的接口；
ICameraDeviceCallBack：底層對上層的CallBack接口；
CameraDeviceManager：用于管理CameraDevice，包括查找，打開，關(guān)閉等。

2、Pipeline介紹

PipelineModel是HAL3核心架構(gòu)，對上需要開放對Pipeline創(chuàng)建 & 操作的API，對下需要建立Pipeline & 管理Pipeline的生命周期。PipelineModel會針對不同的場景創(chuàng)建不同的Pipeline和HWNode，HWNode向下傳輸APP層的命令，向上傳遞圖形數(shù)據(jù)：
P1Node： pipeline的root node，input app命令，output raw data to P2CaptureNode and P2StreamNode；
P2CaptureNode：轉(zhuǎn)換raw data to yuvs，Support scale/crop；
P2StreamingNode：和P2CaptureNode功能類似；
*JPEGNode： Convert YUV to Jpeg；
FDNode： Generate the FD information；

二、Camera Open流程

1、在APP層調(diào)用openCam后會調(diào)用的CameraDevice層，最后調(diào)用到driver中，整體的調(diào)用流程如下：

程序員Android 轉(zhuǎn)于網(wǎng)絡(luò)

文件位置：
./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;
}

這里主要看PipelineModel的Open函數(shù)如下：
文件位置：
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;
}

再調(diào)用mHalDeviceAdapter的Open用于初始化DeviceAdapter，這里重點看powerOn接口，這里的powerOn有另起一個線程去操作sensor，等待sensor上電完成后對3A進行powerOn操作：
文件位置：
vendor/mediatek/proprietary/hardware/mtkcam3/pipeline/model/adapter/HalDeviceAdapter.cpp

virtual auto powerOn() -> bool override
{
    //1.調(diào)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();
        }
    }
}

這里繼續(xù)跟蹤mvHalSensor[i]->powerOn，會調(diào)用到HalSensor.cpp中，這里到了和Driver交互的部分：

(1) 初始化SeninfDrv；

(2) 初始化SensorDrv；

(3) setSensorMclk和setSensorMclkDrivingCurrent；

(4) 最后通過mpSensorDrv->open；

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);
            }
        }
    }
}

mpSensorDrv->open會調(diào)用如下，到此featureControl調(diào)用到驅(qū)動的SENSOR_FEATURE_OPEN：
文件位置：
vendor/mediatek/proprietary/hardware/mtkcam/drv/src/sensor/mt6765/../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);
}

友情推薦：

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MTK Camera Open 流程

一、整體介紹

1、MiddleWare(MW)層介紹

2、Pipeline介紹

二、Camera Open流程

一、整體介紹

二、Camera Open流程