SM8250CAMERA流程分析原帖：https://blog.csdn.net/wjky2014/article/details/110212051

和你一起终身学习，这里是程序员Android

经典好文推荐，通过阅读本文，您将收获以下知识点:

1.app层 MainActivity.java CameraManager 可以直接调用 其openCamera 方法

getCameraIdList 用来存储可用Camera设备 list， openCamera 成功后会调用CameraDevice.StateCallback#onOpened，

然后会创建Session CameraDevice#createCaptureSession 以及拍照CameraDevice#createCaptureRequest等等。

1. public class MainActivity extends AppCompatActivity {

3. protected void onCreate(@Nullable Bundle savedInstanceState) {

5. ... ...

6. //

7. CameraManager mCameraManager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);

8. ... ...

10. }

2.CameraManager.java
(frameworks\base\core\java\android\hardware\camera2)

CameraManager 会根据传递过来的参数不同，调用不同的Opencamera 方法。

2. @RequiresPermission(android.Manifest.permission.CAMERA)

3. public void openCamera(@NonNull String cameraId,

4. @NonNull final CameraDevice.StateCallback callback, @Nullable Handler handler)

5. throws CameraAccessException {

7. openCameraForUid(cameraId, callback, CameraDeviceImpl.checkAndWrapHandler(handler),

8. USE_CALLING_UID);

9. }

10. // CameraDeviceImpl.checkAndWrapHandler 会将 Handler 封装成Executor 类型

11. public static Executor checkAndWrapHandler(Handler handler) {

12. return new CameraHandlerExecutor(checkHandler(handler));

13. }

15. @RequiresPermission(android.Manifest.permission.CAMERA)

16. public void openCamera(@NonNull String cameraId,

17. @NonNull @CallbackExecutor Executor executor,

18. @NonNull final CameraDevice.StateCallback callback)

19. throws CameraAccessException {

21. openCameraForUid(cameraId, callback, executor, USE_CALLING_UID);

22. }

从代码中看，openCamera 参数主要区别是 CallbackExecutor 、Handler 这两个，最终都会走到 openCameraForUid 方法。
openCameraForUid 主要是 根据 Camera id 打开一个Camera 连接。

1. public void openCameraForUid(@NonNull String cameraId,

2. @NonNull final CameraDevice.StateCallback callback, @NonNull Executor executor,

3. int clientUid)

4. throws CameraAccessException {

5. //

6. openCameraDeviceUserAsync(cameraId, callback, executor, clientUid);

8. }

openCameraForUid 会调用 openCameraDeviceUserAsync 方法去帮助opencamera 连接的创建

1. private CameraDevice openCameraDeviceUserAsync(String cameraId,

2. CameraDevice.StateCallback callback, Executor executor, final int uid)

3. throws CameraAccessException {

4. // 获取 特定camera的特性

5. CameraCharacteristics characteristics = getCameraCharacteristics(cameraId);

7. android.hardware.camera2.impl.CameraDeviceImpl deviceImpl = new CameraDeviceImpl();

8. ICameraDeviceCallbacks callbacks = deviceImpl.getCallbacks()

10. if (supportsCamera2ApiLocked(cameraId)) {

11. // Use cameraservice's cameradeviceclient implementation for HAL3.2+ devices

12. ICameraService cameraService = CameraManagerGlobal.get().getCameraService();

14. cameraService.connectDevice(callbacks, cameraId,mContext.getOpPackageName(), uid);

16. }else{

17. ... ...

18. }

19. // TODO: factor out callback to be non-nested, then move setter to constructor

20. // For now, calling setRemoteDevice will fire initial

21. // onOpened/onUnconfigured callbacks.

22. // This function call may post onDisconnected and throw CAMERA_DISCONNECTED if

23. // cameraUser dies during setup.

24. deviceImpl.setRemoteDevice(cameraUser);

26. }

cameraService是通过Binder 继承 ICameraServiceListener.Stub

1. private static final class CameraManagerGlobal extends ICameraServiceListener.Stub

2. implements IBinder.DeathRecipient {

3. // This must match the ICameraService definition

4. private static final String CAMERA_SERVICE_BINDER_NAME = "media.camera";

6. public ICameraService getCameraService() {

8. synchronized(mLock) {

9. //

10. connectCameraServiceLocked();

11. return mCameraService;

12. }

13. }

15. private void connectCameraServiceLocked() {

16. IBinder cameraServiceBinder = ServiceManager.getService(CAMERA_SERVICE_BINDER_NAME);

18. ICameraService cameraService = ICameraService.Stub.asInterface(cameraServiceBinder);

20. for (CameraStatus c : cameraStatuses) {

21. onStatusChangedLocked(c.status, c.cameraId);

22. }

23. mCameraService = cameraService;

24. }

25. }

3.CameraService.cpp
(frameworks\av\services\camera\libcameraservice)

cameraService.connectDevice 通过AIDL 到用到 CameraService.cpp 中的connectDevice 方法。

1. Status CameraService::connectDevice(

2. const sp<hardware::camera2::ICameraDeviceCallbacks>& cameraCb,

3. const String16& cameraId,

4. const String16& clientPackageName,

5. int clientUid,

6. /*out*/

7. sp<hardware::camera2::ICameraDeviceUser>* device) {

8. //调用connectHelper 方法

9. ret = connectHelper<hardware::camera2::ICameraDeviceCallbacks,CameraDeviceClient>(cameraCb, id,

10. /*api1CameraId*/-1,

11. CAMERA_HAL_API_VERSION_UNSPECIFIED, clientPackageNameAdj,

12. clientUid, USE_CALLING_PID, API_2, /*shimUpdateOnly*/ false, /*out*/client);

14. }

connectDevice 会调用到 connectHelper 方法

2. Status CameraService::connectHelper(){

4. // 闪光灯进入预准备阶段

5. mFlashlight->prepareDeviceOpen(cameraId);

7. //获取当前设备的Version

8. int deviceVersion = getDeviceVersion(cameraId, /*out*/&facing);

11. // 初始化CameraproviderManager

12. err = client->initialize(mCameraProviderManager, mMonitorTags);

14. }

4.CameraProviderManager.cpp
(frameworks\av\services\camera\libcameraservice\common)

2. status_t CameraProviderManager::initialize(wp<CameraProviderManager::StatusListener> listener,

3. ServiceInteractionProxy* proxy) {

4. // 调用 addProviderLocked 方法

5. for (const auto& instance : mServiceProxy->listServices()) {

6. this->addProviderLocked(instance);

7. }

9. }

11. status_t CameraProviderManager::addProviderLocked(const std::string& newProvider) {

13. sp<ProviderInfo> providerInfo = new ProviderInfo(newProvider, this);

14. status_t res = providerInfo->initialize(interface, mDeviceState);

16. }

18. //ProviderInfo::initialize 初始化方法

19. status_t CameraProviderManager::ProviderInfo::initialize(){

22. status_t res = addDevice(device, common::V1_0::CameraDeviceStatus::PRESENT, &id);

24. }

27. status_t CameraProviderManager::ProviderInfo::addDevice(const std::string& name,

28. CameraDeviceStatus initialStatus, /*out*/ std::string* parsedId) {

30. //

31. deviceInfo = initializeDeviceInfo<DeviceInfo3>(name, mProviderTagid,

32. id, minor);

34. }

37. std::unique_ptr<CameraProviderManager::ProviderInfo::DeviceInfo>

38. CameraProviderManager::ProviderInfo::initializeDeviceInfo(){

39. // 后续调用待完善 如何 跳转到 Camera3device.cpp 的initialize 方法

40. return std::unique_ptr<DeviceInfo>(

41. new DeviceInfoT(name, tagId, id, minorVersion, resourceCost, this,

42. mProviderPublicCameraIds, cameraInterface));

43. }

5.Camera3Device.cpp
(frameworks\av\services\camera\libcameraservice\device3)

1. status_t Camera3Device::initialize(sp<CameraProviderManager> manager, const String8& monitorTags) {

3. // 调用 CameraProviderManager openSession

4. ATRACE_BEGIN("CameraHal::openSession");

5. status_t res = manager->openSession(mId.string(), this,

6. /*out*/ &session);

7. ATRACE_END();

9. return initializeCommonLocked();

10. }

6.CameraProviderManager.cpp
(frameworks\av\services\camera\libcameraservice\common)

1. status_t CameraProviderManager::openSession(const std::string &id,

2. const sp<device::V3_2::ICameraDeviceCallback>& callback,

3. /*out*/

4. sp<device::V3_2::ICameraDeviceSession> *session) {

6. auto interface = deviceInfo3->startDeviceInterface<

7. CameraProviderManager::ProviderInfo::DeviceInfo3::InterfaceT>();

9. ret = interface->open(callback, [&status, &session]

10. (Status s, const sp<device::V3_2::ICameraDeviceSession>& cameraSession) {

11. status = s;

12. if (status == Status::OK) {

13. *session = cameraSession;

14. }

15. });

18. }

7.ICameraDevice.hal
(hardware\interfaces\camera\device\3.2)

1. //Power on and initialize this camera device for active use, returning a

2. //session handle for active operations.

3. open(ICameraDeviceCallback callback) generates

4. (Status status, ICameraDeviceSession session);

8.CameraDevice.cpp
(hardware\interfaces\camera\device\3.2\default)

1. Return<void> CameraDevice::open(const sp<ICameraDeviceCallback>& callback,

2. ICameraDevice::open_cb _hidl_cb) {

5. /** Open HAL device */

6. status_t res;

7. camera3_device_t *device;

8. // 1. 开始 open Hal Device

9. ATRACE_BEGIN("camera3->open");

10. res = mModule->open(mCameraId.c_str(),

11. reinterpret_cast<hw_device_t**>(&device));

12. ATRACE_END();

14. // 2. 获取Camera 信息

15. res = mModule->getCameraInfo(mCameraIdInt, &info);

17. // 3. 创建 CameraDeviceSession

18. session = createSession(device, info.static_camera_characteristics, callback);

19. }

1. CameraModule.cpp
   (hardware\interfaces\camera\common\1.0\default)

1. int CameraModule::open(const char* id, struct hw_device_t** device) {

2. int res;

3. ATRACE_BEGIN("camera_module->open");

4. res = filterOpenErrorCode(mModule->common.methods->open(&mModule->common, id, device));

5. ATRACE_END();

6. return res;

7. }

10.Camxhal3entry.cpp
(vendor\qcom\proprietary\camx\src\core\hal)

1. int open(

2. const struct hw_module_t* pHwModuleAPI,

3. const char* pCameraIdAPI,

4. struct hw_device_t** ppHwDeviceAPI)

5. {

6. /// @todo (CAMX-43) - Reload Jumptable from settings

7. JumpTableHAL3* pHAL3 = static_cast<JumpTableHAL3*>(g_dispatchHAL3.GetJumpTable());

9. return pHAL3->open(pHwModuleAPI, pCameraIdAPI, ppHwDeviceAPI);

10. }

11.Camxhal3.cpp
(vendor\qcom\proprietary\camx\src\core\hal)

1. static int open(){

2. // 检查CameraId 是否有效

3. cameraId = OsUtils::StrToUL(pCameraIdAPI, &pNameEnd, 10);

5. // 检查闪光灯状态，如果 on 状态，需要off

6. HAL3Module::GetInstance()->ReserveTorchForCamera(

7. GetCHIAppCallbacks()->chi_remap_camera_id(cameraId, IdRemapTorch), cameraId);

9. // 调用 Camxhal3module ProcessCameraOpen 方法

10. result = HAL3Module::GetInstance()->ProcessCameraOpen(logicalCameraId, &extend);

12. // 创建HalDevice 实例并初始化

13. pHALDevice = HALDevice::Create(pHwModule, logicalCameraId, cameraId);

14. }

12.Camxhal3module.cpp
(vendor\qcom\proprietary\camx\src\core\hal)

1. CamxResult HAL3Module::ProcessCameraOpen(){

3. result = m_ChiAppCallbacks.chi_extend_open(logicalCameraId, pPriv);

4. }

13.Chxextensioninterface.cpp
(vendor\qcom\proprietary\chi-cdk\core\chiframework)

1. static CDKResult chi_extend_open(){

3. ExtensionModule* pExtensionModule = ExtensionModule::GetInstance();

4. CHX_LOG_DEBUG("[OP_EXT] OPEN_CAMERA E cameraId %d", cameraId);

5. CDKResult result = pExtensionModule->ExtendOpen(cameraId, priv);

6. CHX_LOG_DEBUG("[OP_EXT] OPEN_CAMERA X");

7. }

14.Chxextensionmodule.cpp
(vendor\qcom\proprietary\chi-cdk\core\chiframework)

1. CDKResult ExtensionModule::ExtendOpen(){

3. // 调用 Perflock 提高 opencamera 性能

4. m_pPerfLockManager[logicalCameraId] = PerfLockManager::Create();

6. if (PERF_LOCK_OPEN_CAMERA != m_previousPowerHint)

7. {

9. m_pPerfLockManager[logicalCameraId]->ReleasePerfLock(m_previousPowerHint);

10. m_pPerfLockManager[logicalCameraId]->AcquirePerfLock(PERF_LOCK_OPEN_CAMERA, 10000);

11. m_previousPowerHint = PERF_LOCK_OPEN_CAMERA;

12. }

13. // open 结束返回到 camxhal3.cpp

14. }

15.Camxhal3.cpp
(vendor\qcom\proprietary\camx\src\core\hal)

1. static int open(){

2. // 检查CameraId 是否有效

3. cameraId = OsUtils::StrToUL(pCameraIdAPI, &pNameEnd, 10);

5. // 检查闪光灯状态，如果 on 状态，需要off

6. HAL3Module::GetInstance()->ReserveTorchForCamera(

7. GetCHIAppCallbacks()->chi_remap_camera_id(cameraId, IdRemapTorch), cameraId);

9. // 调用 Camxhal3module ProcessCameraOpen 方法

10. result = HAL3Module::GetInstance()->ProcessCameraOpen(logicalCameraId, &extend);

12. // 创建HalDevice 实例并初始化

13. pHALDevice = HALDevice::Create(pHwModule, logicalCameraId, cameraId);

14. }

16.Camxhaldevice.cpp
(vendor\qcom\proprietary\camx\src\core\hal)

2. HALDevice* HALDevice::Create(){

4. result = pHALDevice->Initialize(pHwModule, cameraId);

6. }

8. CamxResult HALDevice::Initialize(){

9. ... ...

11. // 初始化完成后，需要返回 CameraDevice.cpp 中继续执行 open 中的方法

12. }

17.CameraDevice.cpp
(hardware\interfaces\camera\device\3.2\default)

1. Return<void> CameraDevice::open(const sp<ICameraDeviceCallback>& callback,

2. ICameraDevice::open_cb _hidl_cb) {

5. /** Open HAL device */

6. status_t res;

7. camera3_device_t *device;

8. // 1. 开始 open Hal Device

9. ATRACE_BEGIN("camera3->open");

10. res = mModule->open(mCameraId.c_str(),

11. reinterpret_cast<hw_device_t**>(&device));

12. ATRACE_END();

14. // 2. 获取Camera 信息

15. res = mModule->getCameraInfo(mCameraIdInt, &info);

17. // 3. 创建 CameraDeviceSession

18. session = createSession(device, info.static_camera_characteristics, callback);

19. }

21. //3. 创建 CameraDeviceSession 方法实现

22. sp<CameraDeviceSession> CameraDevice::createSession(camera3_device_t* device,

23. const camera_metadata_t* deviceInfo,

24. const sp<ICameraDeviceCallback>& callback) {

25. return new CameraDeviceSession(device, deviceInfo, callback);

26. }

18.CameraDeviceSession.cpp
(hardware\interfaces\camera\device\3.2\default) 62313 2020/8/11

1. CameraDeviceSession::CameraDeviceSession(){

3. //调用 initialize 方法

4. mInitFail = initialize();

6. }

8. bool CameraDeviceSession::initialize() {

10. // 初始化完成之后返回 CameraProviderManager

11. }

CamxOpen流程（参考网络）

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