Android Camera CameraService启动流程 (androidP)

Posted 2021-12-06 we1less

cameraserver.rc

路径  frameworks/av/camera/cameraserver/cameraserver.rc

        CameraService是由这个.rc文件启动的关于rc文件参见流程1

service cameraserver /system/bin/cameraserver
    class main
    user cameraserver
    group audio camera input drmrpc readproc
    ioprio rt 4
    writepid /dev/cpuset/camera-daemon/tasks /dev/stune/top-app/tasks
    rlimit rtprio 10 10

---

main_cameraserver.cpp 

路径  frameworks/av/camera/cameraserver/main_cameraserver.cpp 

        CameraService::instantiate() 接口定义在 BinderService 中，CameraService继承它，instantiate() 函数定义在

路径  android/frameworks/native/libs/binder/include/binder/BinderService.h

创建一个new CameraService，名为media.camera并将其加入到 ServiceManager 中。

        getServiceName() = "media.camera"

        因为SP指针的原因下一步调用到的是CameraService::onFirstRef()

int main(int argc __unused, char** argv __unused)
{
    signal(SIGPIPE, SIG_IGN);

    // Set 3 threads for HIDL calls
    hardware::configureRpcThreadpool(3, /*willjoin*/ false);

    sp<ProcessState> proc(ProcessState::self());
    sp<IServiceManager> sm = defaultServiceManager();
    ALOGI("ServiceManager: %p", sm.get());
    CameraService::instantiate();
    ProcessState::self()->startThreadPool();
    IPCThreadState::self()->joinThreadPool();
}


//路径  android/frameworks/native/libs/binder/include/binder/BinderService.h

static void instantiate() { publish(); }

static status_t publish(bool allowIsolated = false,
                            int dumpFlags = IServiceManager::DUMP_FLAG_PRIORITY_DEFAULT) {
        sp<IServiceManager> sm(defaultServiceManager());
        return sm->addService(String16(SERVICE::getServiceName()), new SERVICE(), allowIsolated,
                              dumpFlags);
    }

//路径  frameworks/av/services/camera/libcameraservice/CameraService.h
static char const* getServiceName() { return "media.camera"; }

---

onFirstRef

路径  frameworks/av/services/camera/libcameraservice/CameraService.cpp

        在 CameraService::onFirstRef() 函数中，主要是调用 enumerateProviders() 函数获取CameraProvider信息

        new CameraProviderManager() 之后调用 initialize(), 并将CameraService作为 CameraProviderManager 的成员变量传递进去

void CameraService::onFirstRef()
{
    res = enumerateProviders();
    ...
}

status_t CameraService::enumerateProviders() {    
     ...
        if (nullptr == mCameraProviderManager.get()) {
            mCameraProviderManager = new CameraProviderManager();
            res = mCameraProviderManager->initialize(this);
            ...
        }
        ...
        deviceIds = mCameraProviderManager->getCameraDeviceIds();
    ...
    for (auto& cameraId : deviceIds) {
        String8 id8 = String8(cameraId.c_str());
        onDeviceStatusChanged(id8, CameraDeviceStatus::PRESENT);
    }

    return OK;
}

---

CameraProviderManager::initialize

路径

  frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.cpp

        将上文传递进来的CameraService作为监听保存在CameraProviderManager中，  

        mServiceProxy = sHardwareServiceInteractionProxy       

//路径  
//frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.h

status_t initialize(wp<StatusListener> listener,
            ServiceInteractionProxy *proxy = &sHardwareServiceInteractionProxy);

//路径  
//frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.cpp

const std::string kLegacyProviderName("legacy/0");
const std::string kExternalProviderName("external/0");

CameraProviderManager::sHardwareServiceInteractionProxy{};

status_t CameraProviderManager::initialize(wp<CameraProviderManager::StatusListener> listener,
        ServiceInteractionProxy* proxy) {
    ...
    mListener = listener;
    mServiceProxy = proxy;
    ...
    bool success = mServiceProxy->registerForNotifications(
        /* instance name, empty means no filter */ "",
        this);
    ...
    addProviderLocked(kLegacyProviderName, /*expected*/ false);
    addProviderLocked(kExternalProviderName, /*expected*/ false);

    return OK;
}

 addProviderLocked

路径  

frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.cpp

        newProvider 参数分别是 "legacy/0" 和 "external/0"

        expected = false

        mServiceProxy = sHardwareServiceInteractionProxy

        getService() 在路径为

frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.h
     getService()将会调用         hardware::camera::provider::V2_4::ICameraProvider::getService(serviceName)

        ICameraProvider::getService流程在这篇分析过Android Camera(一) Provider启动流程 (androidP)(HIDL)_we1less的博客-CSDN博客
       所以  interface = CameraProvider 代理(通过ServiceManager获得的)

        在获得CameraProvider代理之后，将会根据 ICameraProvider 填充相应的 providerInfo

status_t CameraProviderManager::addProviderLocked(const std::string& newProvider, bool expected) {
    //循环判断是否已经添加provider
    for (const auto& providerInfo : mProviders) {
     ...
    }
    
    sp<provider::V2_4::ICameraProvider> interface;
    interface = mServiceProxy->getService(newProvider);
    ...
    sp<ProviderInfo> providerInfo =
            new ProviderInfo(newProvider, interface, this);
    status_t res = providerInfo->initialize();
    ...
    mProviders.push_back(providerInfo);

    return OK;
}

//路径
//frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.h

// Standard use case - call into the normal generated static methods which invoke
    // the real hardware service manager
    struct HardwareServiceInteractionProxy : public ServiceInteractionProxy {
        virtual bool registerForNotifications(
                const std::string &serviceName,
                const sp<hidl::manager::V1_0::IServiceNotification>
                &notification) override {
            return hardware::camera::provider::V2_4::ICameraProvider::registerForNotifications(
                    serviceName, notification);
        }
        virtual sp<hardware::camera::provider::V2_4::ICameraProvider> getService(
                const std::string &serviceName) override {
            return hardware::camera::provider::V2_4::ICameraProvider::getService(serviceName);
        }
    };

---

hardware::camera::provider::V2_4::ICameraProvider::getService(serviceName)

路径  

out/soong/.intermediates/hardware/interfaces/camera/provider/2.4/android.hardware.camera.provider@2.4_genc++/gen/android/hardware/camera/provider/2.4/CameraProviderAll.cpp

        getStub = false 时，走此流程，拿到 cameraprovider  一般用于其他服务获取cameraprovider服务，此部分在Android Camera(一) Provider启动流程 (androidP)(HIDL)_we1less的博客-CSDN博客这篇已经分析过所以此处就做个结论：此处的 getRawServiceInternal() 调用参数为 false，getRawServiceInternal() 函数在 CameraProvider 注册为服务的时候调用了，只是调用参数不一致，所以，这里返回的将会是 CameraProvider 代理。

//在路径
/* out/soong/.intermediates/hardware/interfaces/camera/provider/2.4/android.hardware.camera.provider@2.4_genc++_headers/gen/android/hardware/camera/provider/2.4/ICameraProvider.h
中有定义*/

static ::android::sp<ICameraProvider> getService(const ::android::hardware::hidl_string& serviceName, bool getStub=false)  { std::string str(serviceName.c_str());      return getService(str, getStub); }


//调用的则是  注意此时  getStub=false

::android::sp<ICameraProvider> ICameraProvider::getService(const std::string &serviceName, const bool getStub) {
    return ::android::hardware::details::getServiceInternal<BpHwCameraProvider>(serviceName, true, getStub);
}

---

CameraProviderManager::ProviderInfo::initialize

CameraProviderManager::ProviderInfo::ProviderInfo

路径  

frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.cpp

        可以从上文new ProviderInfo(newProvider, interface, this);中看出

        ProviderInfo::mInterface =  CameraProviderManager::interface = CameraProvider 代理

        providerName 分别为  "legacy/0" 和 "external/0"

        在初始化initialize的过程中 调用了mInterface的

                setCallback(this)

                linkToDeath

                getCameraIdList 

                实际上就是调用了HAL层的CameraProvider中的相关函数，关于这个在上一篇说到过，在路径

hardware/interfaces/camera/provider/2.4/ICameraProvider.hal

中有定义 getCameraIdList() generates (Status status, vec<string> cameraDeviceNames);

返回一个由cameraDeviceNames组成的列表，将返回的设备填装到devices中，载将这个取得到的camera信息保存到 mDevices中，至此，CameraService与CameraProvider已经关联起来。
        device的值一般类似以下： device@3.3/legacy/0
        device的值是CameraProvider服务获取device之后，添加 mCameraDeviceNames，
        该变量的含义如下：@3.3  第一个 3 是与camera HAL的版本号相关，只要不是 CAMERA_DEVICE_API_VERSION_1_0，都是3
                                                   第二个 3 是从系统属性 ro.vendor.camera.wrapper.hal3TrebleMinorVersion 获取的，没有则是3
                                         legacy/0 : 则与 CameraProvider 服务相关

//构造器
CameraProviderManager::ProviderInfo::ProviderInfo(
        const std::string &providerName,
        sp<provider::V2_4::ICameraProvider>& interface,
        CameraProviderManager *manager) :
        mProviderName(providerName),
        mInterface(interface),
        mProviderTagid(generateVendorTagId(providerName)),
        mUniqueDeviceCount(0),
        mManager(manager) {
    (void) mManager;
}

status_t CameraProviderManager::ProviderInfo::initialize() {
    status_t res = parseProviderName(mProviderName, &mType, &mId);
    ...
    hardware::Return<Status> status = mInterface->setCallback(this);
    ...
    hardware::Return<bool> linked = mInterface->linkToDeath(this, /*cookie*/ mId);
    ...
    std::vector<std::string> devices;
    hardware::Return<void> ret = mInterface->getCameraIdList([&status, &devices](
            Status idStatus,
            const hardware::hidl_vec<hardware::hidl_string>& cameraDeviceNames) {
        status = idStatus;
        if (status == Status::OK) {
            for (size_t i = 0; i < cameraDeviceNames.size(); i++) {
                //将返回的设备填装到devices中
                devices.push_back(cameraDeviceNames[i]);
            }
        } });
    ...

    sp<StatusListener> listener = mManager->getStatusListener();
    for (auto& device : devices) {
        std::string id;
        status_t res = addDevice(device,
                hardware::camera::common::V1_0::CameraDeviceStatus::PRESENT, &id);
        ...
    }
    ...
    mInitialized = true;
    return OK;
}

---

CameraProviderManager::ProviderInfo::addDevice

 路径  frameworks/av/services/camera/libcameraservice/common/CameraProviderManager.cpp

        根据HAL版本，创建相应的 DeviceInfo

        将上述获取得到的camera信息保存到 mDevices中

status_t CameraProviderManager::ProviderInfo::addDevice(const std::string& name,
        CameraDeviceStatus initialStatus, /*out*/ std::string* parsedId) {
    ...
    uint16_t major, minor;
    std::string type, id;

    status_t res = parseDeviceName(name, &major, &minor, &type, &id);
    ...
    std::unique_ptr<DeviceInfo> deviceInfo;
    switch (major) {
        case 1:
            deviceInfo = initializeDeviceInfo<DeviceInfo1>(name, mProviderTagid,
                    id, minor);
            break;
        case 3:
            deviceInfo = initializeDeviceInfo<DeviceInfo3>(name, mProviderTagid,
                    id, minor);
            break;
        ...
    mDevices.push_back(std::move(deviceInfo));

    mUniqueCameraIds.insert(id);
    ...
    return OK;
}