android6.0 Bluetooth蓝牙源码流程笔记

注:基于mtk平台的android6.0,由于我个人水平有限,代码细节不能详细说明,抱歉

参考文章:

http://blog.csdn.net/shichaog/article/details/52728684

http://blog.csdn.net/baimy1985/article/details/8922508
http://blog.csdn.net/yanli0084/article/details/51821064
谢谢以上大佬

首先从BluetoothAdapter.enable开始

frameworks/base/core/java/android/bluetooth.BluetoothAdapter.java 
   public boolean enable() {
        int state = STATE_OFF;
        if (isEnabled() == true){
            if (DBG) Log.d(TAG, "enable(): BT is already enabled..!");
            return true;
        }
        //Use service interface to get the exact state
        if (mService != null) {
            try {
               state = mService.getState();
            } catch (RemoteException e) {Log.e(TAG, "", e);}
        }

        if (state == BluetoothAdapter.STATE_BLE_ON) {
                Log.e(TAG, "BT is in BLE_ON State");
                notifyUserAction(true);
                return true;
        }
        try {
            if (DBG) Log.d(TAG, "enable");
            return mManagerService.enable();
        } catch (RemoteException e) {Log.e(TAG, "", e);}
        return false;
    }
这个mManagerService是构造函数传来的,再看看单例的getDefaultAdapter

    public static synchronized BluetoothAdapter getDefaultAdapter() {
        if (sAdapter == null) {
            IBinder b = ServiceManager.getService(BLUETOOTH_MANAGER_SERVICE);
            if (b != null) {
                IBluetoothManager managerService = IBluetoothManager.Stub.asInterface(b);
                sAdapter = new BluetoothAdapter(managerService);
            } else {
                Log.e(TAG, "Bluetooth binder is null");
            }
        }
        return sAdapter;
    }

看来有个地方把binder注册成了BLUETOOTH_MANAGER_SERVICE,搜索发现在BluetoothService中


    @Override
    public void onStart() {
        Log.d(TAG, "onStart: publishing BluetoothManagerService");
        publishBinderService(BluetoothAdapter.BLUETOOTH_MANAGER_SERVICE, mBluetoothManagerService);
    }
这个mBluetoothManagerService是BluetoothManagerService.java的实例。

扫描二维码关注公众号,回复: 3878446 查看本文章
    public boolean enable() {
        if ((Binder.getCallingUid() != Process.SYSTEM_UID) &&
            (!checkIfCallerIsForegroundUser())) {
            Log.w(TAG,"enable(): not allowed for non-active and non system user");
            return false;
        }

        mContext.enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,
                                                "Need BLUETOOTH ADMIN permission");
        if (DBG) {
            Log.d(TAG,"enable():  mBluetooth =" + mBluetooth +
                    " mBinding = " + mBinding);
        }
        /// M: MoMS permission check @{
        if (MobileManagerUtils.isSupported()) {
            checkEnablePermission();
            return true;
        }
        /// @}
        synchronized(mReceiver) {
            mQuietEnableExternal = false;
            mEnableExternal = true;
            // waive WRITE_SECURE_SETTINGS permission check
            sendEnableMsg(false);
        }
        if (DBG) Log.d(TAG, "enable returning");
        return true;
    }
    private void sendEnableMsg(boolean quietMode) {
        mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_ENABLE,
                             quietMode ? 1 : 0, 0));
    }
              case MESSAGE_ENABLE:
                    if (DBG) {
                        Log.d(TAG, "MESSAGE_ENABLE: mBluetooth = " + mBluetooth);
                    }
                    mHandler.removeMessages(MESSAGE_RESTART_BLUETOOTH_SERVICE);
                    mEnable = true;
                    handleEnable(msg.arg1 == 1);
                    break;
    private void handleEnable(boolean quietMode) {
        mQuietEnable = quietMode;

        synchronized(mConnection) {
            if (DBG) Log.d(TAG, "handleEnable: mBluetooth = " + mBluetooth +
                    ", mBinding = " + mBinding + "quietMode = " + quietMode);
            if ((mBluetooth == null) && (!mBinding)) {
                if (DBG) Log.d(TAG, "Bind AdapterService");
                //Start bind timeout and bind
                Message timeoutMsg=mHandler.obtainMessage(MESSAGE_TIMEOUT_BIND);
                mHandler.sendMessageDelayed(timeoutMsg,TIMEOUT_BIND_MS);
                mConnection.setGetNameAddressOnly(false);
                Intent i = new Intent(IBluetooth.class.getName());
                if (!doBind(i, mConnection,Context.BIND_AUTO_CREATE | Context.BIND_IMPORTANT,
                        UserHandle.CURRENT)) {
                    mHandler.removeMessages(MESSAGE_TIMEOUT_BIND);
                    Log.e(TAG, "Fail to bind to: " + IBluetooth.class.getName());
                } else {
                    mBinding = true;
                }
            } else if (mBluetooth != null) {
                if (mConnection.isGetNameAddressOnly()) {
                    // if GetNameAddressOnly is set, we can clear this flag,
                    // so the service won't be unbind
                    // after name and address are saved
                    mConnection.setGetNameAddressOnly(false);
                    //Register callback object
                    try {
                        mBluetooth.registerCallback(mBluetoothCallback);
                    } catch (RemoteException re) {
                        Log.e(TAG, "Unable to register BluetoothCallback",re);
                    }
                    //Inform BluetoothAdapter instances that service is up
                    sendBluetoothServiceUpCallback();
                }

                //Enable bluetooth
                try {
                    if (!mQuietEnable) {
                        if(!mBluetooth.enable()) {
                            Log.e(TAG,"IBluetooth.enable() returned false");
                        }
                    }
                    else {
                        if(!mBluetooth.enableNoAutoConnect()) {
                            Log.e(TAG,"IBluetooth.enableNoAutoConnect() returned false");
                        }
                    }
                } catch (RemoteException e) {
                    Log.e(TAG,"Unable to call enable()",e);
                }
            }
        }
    }
    boolean doBind(Intent intent, ServiceConnection conn, int flags, UserHandle user) {
        ComponentName comp = intent.resolveSystemService(mContext.getPackageManager(), 0);
        intent.setComponent(comp);
        if (comp == null || !mContext.bindServiceAsUser(intent, conn, flags, user)) {
            Log.e(TAG, "Fail to bind to: " + intent);
            return false;
        }
        return true;
    }
这个intent指向packages/apps/Bluetooth的AdapterService

Manifest.xml
        <service
            android:process="@string/process"
            android:name = ".btservice.AdapterService">
            <intent-filter>
                <action android:name="android.bluetooth.IBluetooth" />
            </intent-filter>
        </service>
bindService的时候注意看这个mConnection,它是BluetoothServiceConnection的实例,在onServiceConnected里

        public void onServiceConnected(ComponentName className, IBinder service) {
            if (DBG) Log.d(TAG, "BluetoothServiceConnection: " + className.getClassName());
            Message msg = mHandler.obtainMessage(MESSAGE_BLUETOOTH_SERVICE_CONNECTED);
            // TBD if (className.getClassName().equals(IBluetooth.class.getName())) {
            if (className.getClassName().equals("com.android.bluetooth.btservice.AdapterService")) {
                msg.arg1 = SERVICE_IBLUETOOTH;
                // } else if (className.getClassName().equals(IBluetoothGatt.class.getName())) {
            } else if (className.getClassName().equals("com.android.bluetooth.gatt.GattService")) {
                msg.arg1 = SERVICE_IBLUETOOTHGATT;
            } else {
                Log.e(TAG, "Unknown service connected: " + className.getClassName());
                return;
            }
            msg.obj = service;
            mHandler.sendMessage(msg);
        }
                case MESSAGE_BLUETOOTH_SERVICE_CONNECTED:
                {
                    if (DBG) Log.d(TAG,"MESSAGE_BLUETOOTH_SERVICE_CONNECTED: " + msg.arg1);

                    IBinder service = (IBinder) msg.obj;
                    synchronized(mConnection) {
                        if (msg.arg1 == SERVICE_IBLUETOOTHGATT) {
                            mBluetoothGatt = IBluetoothGatt.Stub.asInterface(service);
                            onBluetoothGattServiceUp();
                            break;
                        } // else must be SERVICE_IBLUETOOTH

                        //Remove timeout
                        mHandler.removeMessages(MESSAGE_TIMEOUT_BIND);

                        mBinding = false;
                        mBluetooth = IBluetooth.Stub.asInterface(service);

                        try {
                            boolean enableHciSnoopLog = (Settings.Secure.getInt(mContentResolver,
                                Settings.Secure.BLUETOOTH_HCI_LOG, 0) == 1);
                            if (!mBluetooth.configHciSnoopLog(enableHciSnoopLog)) {
                                Log.e(TAG,"IBluetooth.configHciSnoopLog return false");
                            }
                        } catch (RemoteException e) {
                            Log.e(TAG,"Unable to call configHciSnoopLog", e);
                        }

                        if (mConnection.isGetNameAddressOnly()) {
                            //Request GET NAME AND ADDRESS
                            Message getMsg = mHandler.obtainMessage(MESSAGE_GET_NAME_AND_ADDRESS);
                            mHandler.sendMessage(getMsg);
                            if (!mEnable) return;
                        }

                        mConnection.setGetNameAddressOnly(false);
                        //Register callback object
                        try {
                            mBluetooth.registerCallback(mBluetoothCallback);
                        } catch (RemoteException re) {
                            Log.e(TAG, "Unable to register BluetoothCallback",re);
                        }
                        //Inform BluetoothAdapter instances that service is up
                        sendBluetoothServiceUpCallback();

                        //Do enable request
                        try {
                            if (mQuietEnable == false) {
                                if(!mBluetooth.enable()) {
                                    Log.e(TAG,"IBluetooth.enable() returned false");
                                }
                            }
                            else
                            {
                                if(!mBluetooth.enableNoAutoConnect()) {
                                    Log.e(TAG,"IBluetooth.enableNoAutoConnect() returned false");
                                }
                            }
                        } catch (RemoteException e) {
                            Log.e(TAG,"Unable to call enable()",e);
                        }
                    }

                    if (!mEnable) {
                        waitForOnOff(true, false);
                        handleDisable();
                        waitForOnOff(false, false);
                    }
                    break;
                }
看到没,刚才mBluetooth 为空才去bindService,这个bind完成也要调用mBluetooth.enable()

在AdapterService的onBind会返回AdapterServiceBinder,看下AdapterServiceBinder

        public boolean enable() {
            if ((Binder.getCallingUid() != Process.SYSTEM_UID) &&
                (!Utils.checkCaller())) {
                Log.w(TAG, "enable() - Not allowed for non-active user and non system user");
                return false;
            }
            AdapterService service = getService();
            if (service == null) return false;
            return service.enable();
        }
最终调用AdapterService的enable()

AdapterService
     public synchronized boolean enable(boolean quietMode) {
         enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM, "Need BLUETOOTH ADMIN permission");

         debugLog("enable() - Enable called with quiet mode status =  " + mQuietmode);
         mQuietmode = quietMode;
         Message m = mAdapterStateMachine.obtainMessage(AdapterState.BLE_TURN_ON);
         mAdapterStateMachine.sendMessage(m);
         return true;
     }
这里和android4.2的不太一样,打开了ble?先不管这个。看看AdapterState内部类OffState的处理

            switch(msg.what) {
               case BLE_TURN_ON:
                   notifyAdapterStateChange(BluetoothAdapter.STATE_BLE_TURNING_ON);
                   mPendingCommandState.setBleTurningOn(true);
                   transitionTo(mPendingCommandState);
                   sendMessageDelayed(BLE_START_TIMEOUT, BLE_START_TIMEOUT_DELAY);
                   adapterService.BleOnProcessStart();
                   break;
AdapterService.java
    void BleOnProcessStart() {
        debugLog("BleOnProcessStart()");
        Class[] supportedProfileServices = Config.getSupportedProfiles();
        //Initialize data objects
        debugLog("supportedProfileServices.length = " + supportedProfileServices.length);
        for (int i=0; i < supportedProfileServices.length;i++) {
            debugLog("supportedProfileServices[" + i + "]: " + supportedProfileServices[i].getName());
            mProfileServicesState.put(supportedProfileServices[i].getName(),BluetoothAdapter.STATE_OFF);
        }
        mRemoteDevices = new RemoteDevices(this);
        mAdapterProperties.init(mRemoteDevices);

        debugLog("BleOnProcessStart() - Make Bond State Machine");
        mBondStateMachine = BondStateMachine.make(this, mAdapterProperties, mRemoteDevices);

        mJniCallbacks.init(mBondStateMachine,mRemoteDevices);

        //FIXME: Set static instance here???
        setAdapterService(this);

        //Start Gatt service
        setGattProfileServiceState(supportedProfileServices,BluetoothAdapter.STATE_ON);
    }
这个把声明支持的profile加载进来,具体不分析了,只上xml配置

config.xml
<resources>
    <bool name="profile_supported_a2dp">true</bool>
    <bool name="profile_supported_a2dp_sink">false</bool>
    <bool name="profile_supported_hdp">true</bool>
    <bool name="profile_supported_hs_hfp">true</bool>
    <bool name="profile_supported_hfpclient">false</bool>
    <bool name="profile_supported_hid">true</bool>
    <bool name="profile_supported_opp">true</bool>
    <bool name="profile_supported_pan">true</bool>
    <bool name="profile_supported_pbap">true</bool>
    <bool name="profile_supported_gatt">true</bool>
    <bool name="pbap_include_photos_in_vcard">false</bool>
    <bool name="pbap_use_profile_for_owner_vcard">true</bool>
    <bool name="profile_supported_map">true</bool>
    <bool name="profile_supported_avrcp_controller">false</bool>
    <bool name="profile_supported_sap">false</bool>
再看看setGattProfileServiceState
AdapterService.java
    private void setGattProfileServiceState(Class[] services, int state) {
        if (state != BluetoothAdapter.STATE_ON && state != BluetoothAdapter.STATE_OFF) {
            Log.w(TAG,"setGattProfileServiceState(): invalid state...Leaving...");
            return;
        }

        int expectedCurrentState= BluetoothAdapter.STATE_OFF;
        int pendingState = BluetoothAdapter.STATE_TURNING_ON;

        if (state == BluetoothAdapter.STATE_OFF) {
            expectedCurrentState= BluetoothAdapter.STATE_ON;
            pendingState = BluetoothAdapter.STATE_TURNING_OFF;
        }

        for (int i=0; i <services.length;i++) {
            String serviceName = services[i].getName();
            String simpleName = services[i].getSimpleName();

            if (simpleName.equals("GattService")) {
                Integer serviceState = mProfileServicesState.get(serviceName);

                if(serviceState != null && serviceState != expectedCurrentState) {
                    debugLog("setProfileServiceState() - Unable to "
                        + (state == BluetoothAdapter.STATE_OFF ? "start" : "stop" )
                        + " service " + serviceName
                        + ". Invalid state: " + serviceState);
                        continue;
                }
                debugLog("setProfileServiceState() - "
                    + (state == BluetoothAdapter.STATE_OFF ? "Stopping" : "Starting")
                    + " service " + serviceName);

                mProfileServicesState.put(serviceName,pendingState);
                Intent intent = new Intent(this,services[i]);
                intent.putExtra(EXTRA_ACTION,ACTION_SERVICE_STATE_CHANGED);
                intent.putExtra(BluetoothAdapter.EXTRA_STATE,state);
                startService(intent);
                return;
            }
        }
    }
打开了GattService.java,GattService继承了ProfileService,在ProfileService的onStartCommand中

调用了notifyProfileServiceStateChanged(BluetoothAdapter.STATE_ON);

    protected void notifyProfileServiceStateChanged(int state) {
        //Notify adapter service
        if (mAdapterService != null) {
            mAdapterService.onProfileServiceStateChanged(getClass().getName(), state);
        }
    }

AdapterService.java
    public void onProfileServiceStateChanged(String serviceName, int state) {
        Message m = mHandler.obtainMessage(MESSAGE_PROFILE_SERVICE_STATE_CHANGED);
        m.obj=serviceName;
        m.arg1 = state;
        mHandler.sendMessage(m);
    }
            switch (msg.what) {
                case MESSAGE_PROFILE_SERVICE_STATE_CHANGED: {
                    debugLog("handleMessage() - MESSAGE_PROFILE_SERVICE_STATE_CHANGED");
                    processProfileServiceStateChanged((String) msg.obj, msg.arg1);
                }
                    break;
    private void processProfileServiceStateChanged(String serviceName, int state) {
...
        if (isBleTurningOn) {
            if (serviceName.equals("com.android.bluetooth.gatt.GattService")) {
                debugLog("GattService is started");
                mAdapterStateMachine.sendMessage(mAdapterStateMachine.obtainMessage(AdapterState.BLE_STARTED));
                return;
            }

        } 
还是在OffState中

                case BLE_STARTED:
                    //Remove start timeout
                    removeMessages(BLE_START_TIMEOUT);

                    //Enable
                    boolean isGuest = UserManager.get(mAdapterService).isGuestUser();
                    if (!adapterService.enableNative(isGuest)) {
                        errorLog("Error while turning Bluetooth on");
                        notifyAdapterStateChange(BluetoothAdapter.STATE_OFF);
                        transitionTo(mOffState);
                    } else {
                        sendMessageDelayed(ENABLE_TIMEOUT, ENABLE_TIMEOUT_DELAY);
                    }
                    break;
调用了AdapterService的enableNative方法,这是个jni调用,在com_android_bluetooth_btservice_AdapterService.cpp中声明了该方法

static jboolean enableNative(JNIEnv* env, jobject obj, jboolean isGuest) {
    ALOGV("%s:",__FUNCTION__);

    jboolean result = JNI_FALSE;
    if (!sBluetoothInterface) return result;

    int ret = sBluetoothInterface->enable(isGuest == JNI_TRUE ? 1 : 0);
    result = (ret == BT_STATUS_SUCCESS || ret == BT_STATUS_DONE) ? JNI_TRUE : JNI_FALSE;
    return result;
}

调用了sBluetoothInterface->enable,这个 sBluetoothInterface在classInitNative中初始化了

static void classInitNative(JNIEnv* env, jclass clazz) {
    int err;
    hw_module_t* module;
...
   char value[PROPERTY_VALUE_MAX];
    property_get("bluetooth.mock_stack", value, "");

    const char *id = (strcmp(value, "1")? BT_STACK_MODULE_ID : BT_STACK_TEST_MODULE_ID);

    err = hw_get_module(id, (hw_module_t const**)&module);

    if (err == 0) {
        hw_device_t* abstraction;
        err = module->methods->open(module, id, &abstraction);
        if (err == 0) {
            bluetooth_module_t* btStack = (bluetooth_module_t *)abstraction;
            sBluetoothInterface = btStack->get_bluetooth_interface();
        } else {
           ALOGE("Error while opening Bluetooth library");
        }
    } else {
        ALOGE("No Bluetooth Library found");
    }
hw_get_module是定义在hardware/libhardware/Hardware.c中的方法,jni文件的.mk中声明了LOCAL_SHARED_LIBRARIES+=libhardware,所以ok

int hw_get_module(const char *id, const struct hw_module_t **module)
{
    return hw_get_module_by_class(id, NULL, module);
}
static int hw_module_exists(char *path, size_t path_len, const char *name,
                            const char *subname)
{
...
    return load(class_id, path, module);
}
static int load(const char *id,
        const char *path,
        const struct hw_module_t **pHmi)
{
    int status = -EINVAL;
    void *handle = NULL;
    struct hw_module_t *hmi = NULL;

    /*
     * load the symbols resolving undefined symbols before
     * dlopen returns. Since RTLD_GLOBAL is not or'd in with
     * RTLD_NOW the external symbols will not be global
     */
    handle = dlopen(path, RTLD_NOW);
    if (handle == NULL) {
        char const *err_str = dlerror();
        ALOGE("load: module=%s\n%s", path, err_str?err_str:"unknown");
        status = -EINVAL;
        goto done;
    }

    /* Get the address of the struct hal_module_info. */
    const char *sym = HAL_MODULE_INFO_SYM_AS_STR;
    hmi = (struct hw_module_t *)dlsym(handle, sym);
    if (hmi == NULL) {
        ALOGE("load: couldn't find symbol %s", sym);
        status = -EINVAL;
        goto done;
    }

    /* Check that the id matches */
    if (strcmp(id, hmi->id) != 0) {
        ALOGE("load: id=%s != hmi->id=%s", id, hmi->id);
        status = -EINVAL;
        goto done;
    }

    hmi->dso = handle;

    /* success */
    status = 0;

    done:
    if (status != 0) {
        hmi = NULL;
        if (handle != NULL) {
            dlclose(handle);
            handle = NULL;
        }
    } else {
        ALOGV("loaded HAL id=%s path=%s hmi=%p handle=%p",
                id, path, *pHmi, handle);
    }

    *pHmi = hmi;

    return status;
}
这段代码不太懂,感觉就是打开一个c文件,传入id是BT_STACK_MODULE_ID,因为const char *id = (strcmp(value, "1")? BT_STACK_MODULE_ID : BT_STACK_TEST_MODULE_ID);后面那个明显是test的啊

至于BT_STACK_MODULE_ID,在hardware/libhardware/include/hardware/Bluetooth.h中定义了

#define BT_STACK_MODULE_ID "bluetooth"

看下system/bt/btif/src/Bluetooth.c,果然找到相关方法

const bt_interface_t* bluetooth__get_bluetooth_interface ()
{
    /* fixme -- add property to disable bt interface ? */

    return &bluetoothInterface;
}
static const bt_interface_t bluetoothInterface = {
    sizeof(bluetoothInterface),
    init,
    enable,
    disable,
    cleanup,
    get_adapter_properties,
    get_adapter_property,
    set_adapter_property,
    get_remote_device_properties,
    get_remote_device_property,
    set_remote_device_property,
    get_remote_service_record,
    get_remote_services,
    start_discovery,
    cancel_discovery,
    create_bond,
    remove_bond,
    cancel_bond,
    get_connection_state,
    pin_reply,
    ssp_reply,
    get_profile_interface,
    dut_mode_configure,
    dut_mode_send,
#if BLE_INCLUDED == TRUE
    le_test_mode,
#else
    NULL,
#endif
    config_hci_snoop_log,
    set_os_callouts,
    read_energy_info,
    dump,
    config_clear
};
static int enable(bool start_restricted) {
  LOG_INFO(LOG_TAG, "%s: start restricted = %d", __func__, start_restricted);

  restricted_mode = start_restricted;

  if (!interface_ready())
    return BT_STATUS_NOT_READY;
 stack_manager_get_interface()->start_up_stack_async();
  return BT_STATUS_SUCCESS;
}


 stack_manager_get_interface在stack_manager.c中 
 

const stack_manager_t *stack_manager_get_interface() {
  ensure_manager_initialized();
  return &interface;
}
static const stack_manager_t interface = {
  init_stack,
  start_up_stack_async,
  shut_down_stack_async,
  clean_up_stack_async,

  get_stack_is_running
};
static void start_up_stack_async(void) {
  thread_post(management_thread, event_start_up_stack, NULL);
}
static void event_start_up_stack(UNUSED_ATTR void *context) {
  if (stack_is_running) {
    LOG_DEBUG("%s stack already brought up.", __func__);
    return;
  }

  ensure_stack_is_initialized();

  LOG_DEBUG("%s is bringing up the stack.", __func__);
  hack_future = future_new();

  // Include this for now to put btif config into a shutdown-able state
  module_start_up(get_module(BTIF_CONFIG_MODULE));
  bte_main_enable();

  if (future_await(hack_future) != FUTURE_SUCCESS) {
    stack_is_running = true; // So stack shutdown actually happens
    event_shut_down_stack(NULL);
    return; }  stack_is_running = true;  LOG_DEBUG("%s finished", __func__);    btif_thread_post(event_signal_stack_up, NULL);}
Bte_main.c

void bte_main_enable()
{
    APPL_TRACE_DEBUG("%s", __FUNCTION__);

    module_start_up(get_module(BTSNOOP_MODULE));
    module_start_up(get_module(HCI_MODULE));

    BTU_StartUp();
}
Btu_init.c

void BTU_StartUp(void)
{
    memset (&btu_cb, 0, sizeof (tBTU_CB));
    btu_cb.trace_level = HCI_INITIAL_TRACE_LEVEL;

    btu_bta_msg_queue = fixed_queue_new(SIZE_MAX);
    if (btu_bta_msg_queue == NULL)
        goto error_exit;

    btu_general_alarm_hash_map = hash_map_new(BTU_GENERAL_ALARM_HASH_MAP_SIZE,
            hash_function_pointer, NULL, (data_free_fn)alarm_free, NULL);
    if (btu_general_alarm_hash_map == NULL)
        goto error_exit;

    if (pthread_mutex_init(&btu_general_alarm_lock, NULL))
        goto error_exit;

    btu_general_alarm_queue = fixed_queue_new(SIZE_MAX);
    if (btu_general_alarm_queue == NULL)
        goto error_exit;

    btu_oneshot_alarm_hash_map = hash_map_new(BTU_ONESHOT_ALARM_HASH_MAP_SIZE,
            hash_function_pointer, NULL, (data_free_fn)alarm_free, NULL);
    if (btu_oneshot_alarm_hash_map == NULL)
        goto error_exit;

    if (pthread_mutex_init(&btu_oneshot_alarm_lock, NULL))
        goto error_exit;

    btu_oneshot_alarm_queue = fixed_queue_new(SIZE_MAX);
    if (btu_oneshot_alarm_queue == NULL)
        goto error_exit;

    btu_l2cap_alarm_hash_map = hash_map_new(BTU_L2CAP_ALARM_HASH_MAP_SIZE,
            hash_function_pointer, NULL, (data_free_fn)alarm_free, NULL);
    if (btu_l2cap_alarm_hash_map == NULL)
        goto error_exit;

    if (pthread_mutex_init(&btu_l2cap_alarm_lock, NULL))
        goto error_exit;

    btu_l2cap_alarm_queue = fixed_queue_new(SIZE_MAX);
    if (btu_l2cap_alarm_queue == NULL)
         goto error_exit;

    bt_workqueue_thread = thread_new(BT_WORKQUEUE_NAME);
    if (bt_workqueue_thread == NULL)
        goto error_exit;

    // Continue startup on bt workqueue thread.
    thread_post(bt_workqueue_thread, btu_task_start_up, NULL);
    return;

  error_exit:;
    LOG_ERROR("%s Unable to allocate resources for bt_workqueue", __func__);
    BTU_ShutDown();
}
前面的都是错误判断,只看thread_post(bt_workqueue_thread, btu_task_start_up, NULL);就行了
Btu_task.c

void btu_task_start_up(UNUSED_ATTR void *context) {
  BT_TRACE(TRACE_LAYER_BTU, TRACE_TYPE_API,
      "btu_task pending for preload complete event");

  LOG_INFO("Bluetooth chip preload is complete");

  BT_TRACE(TRACE_LAYER_BTU, TRACE_TYPE_API,
      "btu_task received preload complete event");

  /* Initialize the mandatory core stack control blocks
     (BTU, BTM, L2CAP, and SDP)
   */
  btu_init_core();

  /* Initialize any optional stack components */
  BTE_InitStack();

  bta_sys_init();

  /* Initialise platform trace levels at this point as BTE_InitStack() and bta_sys_init()
   * reset the control blocks and preset the trace level with XXX_INITIAL_TRACE_LEVEL
   */
#if ( BT_USE_TRACES==TRUE )
  module_init(get_module(BTE_LOGMSG_MODULE));
#endif

  // Inform the bt jni thread initialization is ok.
  btif_transfer_context(btif_init_ok, 0, NULL, 0, NULL);

  fixed_queue_register_dequeue(btu_bta_msg_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_bta_msg_ready,
      NULL);

  fixed_queue_register_dequeue(btu_hci_msg_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_hci_msg_ready,
      NULL);

  fixed_queue_register_dequeue(btu_general_alarm_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_general_alarm_ready,
      NULL);

  fixed_queue_register_dequeue(btu_oneshot_alarm_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_oneshot_alarm_ready,
      NULL);

  fixed_queue_register_dequeue(btu_l2cap_alarm_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_l2cap_alarm_ready,
      NULL);
}

Btif_core.c

void btif_init_ok(UNUSED_ATTR uint16_t event, UNUSED_ATTR char *p_param) {
  BTIF_TRACE_DEBUG("btif_task: received trigger stack init event");
#if (BLE_INCLUDED == TRUE)
  btif_dm_load_ble_local_keys();
#endif
  BTA_EnableBluetooth(bte_dm_evt);
}
system/bt/bta/dm/Bta_dm_api.c
tBTA_STATUS BTA_EnableBluetooth(tBTA_DM_SEC_CBACK *p_cback)
{

    tBTA_DM_API_ENABLE    *p_msg;

    /* Bluetooth disabling is in progress */
    if (bta_dm_cb.disabling)
        return BTA_FAILURE;

    memset(&bta_dm_cb, 0, sizeof(bta_dm_cb));

    bta_sys_register (BTA_ID_DM, &bta_dm_reg );
    bta_sys_register (BTA_ID_DM_SEARCH, &bta_dm_search_reg );

    /* if UUID list is not provided as static data */
    bta_sys_eir_register(bta_dm_eir_update_uuid);

    if ((p_msg = (tBTA_DM_API_ENABLE *) GKI_getbuf(sizeof(tBTA_DM_API_ENABLE))) != NULL)
    {
        p_msg->hdr.event = BTA_DM_API_ENABLE_EVT;
        p_msg->p_sec_cback = p_cback;
        bta_sys_sendmsg(p_msg);
        return BTA_SUCCESS;
    }
    return BTA_FAILURE;

}
这里看看这个BTA_DM_API_ENABLE_EVT是什么,首先看看Bta_dm_int.h声明了一组枚举类型
enum
{
    /* device manager local device API events */
    BTA_DM_API_ENABLE_EVT = BTA_SYS_EVT_START(BTA_ID_DM),
    BTA_DM_API_DISABLE_EVT,
这个BTA_SYS_EVT_START又是什么?通过搜索在Bta_sys.h中找到了这个宏,这里先标志一下
#define BTA_SYS_EVT_START(id)       ((id) << 8) 
system/bt/gki/common/Gki_buffer.c
void *GKI_getbuf (UINT16 size)
{
  BUFFER_HDR_T *header = osi_malloc(size + BUFFER_HDR_SIZE);
  header->status  = BUF_STATUS_UNLINKED;
  header->p_next  = NULL;
  header->Type    = 0;
  header->size = size;
  return header + 1;
}

system/bt/bta/sys/Bta_sys_main.c
void bta_sys_sendmsg(void *p_msg)
{
    // There is a race condition that occurs if the stack is shut down while
    // there is a procedure in progress that can schedule a task via this
    // message queue. This causes |btu_bta_msg_queue| to get cleaned up before
    // it gets used here; hence we check for NULL before using it.
    if (btu_bta_msg_queue)
        fixed_queue_enqueue(btu_bta_msg_queue, p_msg);
}
向消息队列发送msg,这个 btu_bta_msg_queue 是在Btu_init.c里面创建的

system/bt/stack/btu/Btu_init.c
void BTU_StartUp(void)
{
    memset (&btu_cb, 0, sizeof (tBTU_CB));
    btu_cb.trace_level = HCI_INITIAL_TRACE_LEVEL;

    btu_bta_msg_queue = fixed_queue_new(SIZE_MAX);
    if (btu_bta_msg_queue == NULL)
        goto error_exit;
......
相关处理函数在Btu_task.c里注册
system/bt/stack/btu/Btu_task.c
void btu_task_start_up(UNUSED_ATTR void *context) {
......
  fixed_queue_register_dequeue(btu_bta_msg_queue,
      thread_get_reactor(bt_workqueue_thread),
      btu_bta_msg_ready,
      NULL);
void btu_bta_msg_ready(fixed_queue_t *queue, UNUSED_ATTR void *context) {
  BT_HDR *p_msg = (BT_HDR *)fixed_queue_dequeue(queue);
   bta_sys_event(p_msg);
}


system/bt/bta/sys/Bta_sys_main.c

void bta_sys_event(BT_HDR *p_msg)
{
    UINT8       id;
    BOOLEAN     freebuf = TRUE;

    APPL_TRACE_EVENT("BTA got event 0x%x", p_msg->event);

    /* get subsystem id from event */
    id = (UINT8) (p_msg->event >> 8);

    /* verify id and call subsystem event handler */
    if ((id < BTA_ID_MAX) && (bta_sys_cb.reg[id] != NULL))
    {
        freebuf = (*bta_sys_cb.reg[id]->evt_hdlr)(p_msg);
    }
    else
    {
        APPL_TRACE_WARNING("BTA got unregistered event id %d", id);
    }

    if (freebuf)
    {
        GKI_freebuf(p_msg);
    }

}

关键在于freebuf = (*bta_sys_cb.reg[id]->evt_hdlr)(p_msg);这个reg的赋值在

void bta_sys_register(UINT8 id, const tBTA_SYS_REG *p_reg)
{
    bta_sys_cb.reg[id] = (tBTA_SYS_REG *) p_reg;
    bta_sys_cb.is_reg[id] = TRUE;
}
那么,这个id是什么呢,就是上面我们标志的BTA_ID_DM

搜索bta_sys_register (BTA_ID_DM发现是在Bta_dm_api.c有调用

tBTA_STATUS BTA_EnableBluetooth(tBTA_DM_SEC_CBACK *p_cback)
{

    tBTA_DM_API_ENABLE    *p_msg;

    /* Bluetooth disabling is in progress */
    if (bta_dm_cb.disabling)
        return BTA_FAILURE;

    memset(&bta_dm_cb, 0, sizeof(bta_dm_cb));

    bta_sys_register (BTA_ID_DM, &bta_dm_reg );
    bta_sys_register (BTA_ID_DM_SEARCH, &bta_dm_search_reg );

    /* if UUID list is not provided as static data */
    bta_sys_eir_register(bta_dm_eir_update_uuid);

    if ((p_msg = (tBTA_DM_API_ENABLE *) GKI_getbuf(sizeof(tBTA_DM_API_ENABLE))) != NULL)
    {
        p_msg->hdr.event = BTA_DM_API_ENABLE_EVT;
        p_msg->p_sec_cback = p_cback;
        bta_sys_sendmsg(p_msg);
        return BTA_SUCCESS;
    }
    return BTA_FAILURE;
static const tBTA_SYS_REG bta_dm_reg =
{
    bta_dm_sm_execute,
    bta_dm_sm_disable
};

然后在Bta_dm_main.c中

system/bt/bta/dm/Bta_dm_main.c
BOOLEAN bta_dm_sm_execute(BT_HDR *p_msg)
{
    UINT16  event = p_msg->event & 0x00ff;

    APPL_TRACE_EVENT("bta_dm_sm_execute event:0x%x", event);

    /* execute action functions */
    if(event < BTA_DM_NUM_ACTIONS)
    {
        (*bta_dm_action[event])( (tBTA_DM_MSG*) p_msg);
    }

    return TRUE;
}

还记得吗,event=1<<8也就是256,化成二进制就是100000000(1和八个零),而0x00ff是011111111(0和八个一),两个&运算等于0,bta_dm_action的定义也在这个文件中

/* action function list */
const tBTA_DM_ACTION bta_dm_action[] =
{

    /* device manager local device API events */
    bta_dm_enable,            /* 0  BTA_DM_API_ENABLE_EVT */
    bta_dm_disable,           /* 1  BTA_DM_API_DISABLE_EVT */
    bta_dm_set_dev_name,      /* 2  BTA_DM_API_SET_NAME_EVT */
    bta_dm_set_visibility,    /* 3  BTA_DM_API_SET_VISIBILITY_EVT */
    bta_dm_acl_change,        /* 8  BTA_DM_ACL_CHANGE_EVT */
    bta_dm_add_device,        /* 9  BTA_DM_API_ADD_DEVICE_EVT */
    bta_dm_close_acl,        /* 10  BTA_DM_API_ADD_DEVICE_EVT */

    /* security API events */
    bta_dm_bond,              /* 11  BTA_DM_API_BOND_EVT */
    bta_dm_bond_cancel,       /* 12  BTA_DM_API_BOND_CANCEL_EVT */
    bta_dm_pin_reply,         /* 13 BTA_DM_API_PIN_REPLY_EVT */

bta_dm_enable的实现在Bta_dm_act中

void bta_dm_enable(tBTA_DM_MSG *p_data)
{
    tBTA_SYS_HW_MSG *sys_enable_event;
    tBTA_DM_ENABLE enable_event;

    /* if already in use, return an error */
    if( bta_dm_cb.is_bta_dm_active == TRUE  )
    {
        APPL_TRACE_WARNING("%s Device already started by another application", __func__);
        memset(&enable_event, 0, sizeof(tBTA_DM_ENABLE));
        enable_event.status = BTA_FAILURE;
        if (p_data->enable.p_sec_cback != NULL)
            p_data->enable.p_sec_cback(BTA_DM_ENABLE_EVT, (tBTA_DM_SEC *)&enable_event);
        return;
    }

    /* first, register our callback to SYS HW manager */
    bta_sys_hw_register( BTA_SYS_HW_BLUETOOTH, bta_dm_sys_hw_cback );

    /* make sure security callback is saved - if no callback, do not erase the previous one,
    it could be an error recovery mechanism */
    if( p_data->enable.p_sec_cback != NULL  )
    bta_dm_cb.p_sec_cback = p_data->enable.p_sec_cback;
    /* notify BTA DM is now active */
    bta_dm_cb.is_bta_dm_active = TRUE;

    /* send a message to BTA SYS */
    if ((sys_enable_event = (tBTA_SYS_HW_MSG *) GKI_getbuf(sizeof(tBTA_SYS_HW_MSG))) != NULL)
    {
        sys_enable_event->hdr.event = BTA_SYS_API_ENABLE_EVT;
        sys_enable_event->hw_module = BTA_SYS_HW_BLUETOOTH;

        bta_sys_sendmsg(sys_enable_event);
    }
}
看注释应该没错了,前面通过 bta_dm_cb.is_bta_dm_active == TRUE判断是不是正在使用,后面有个 bta_dm_cb.is_bta_dm_active == TRUE,那么中间就应该是打开操作咯,
    /* first, register our callback to SYS HW manager */
    bta_sys_hw_register( BTA_SYS_HW_BLUETOOTH, bta_dm_sys_hw_cback );

    /* make sure security callback is saved - if no callback, do not erase the previous one,
    it could be an error recovery mechanism */
    if( p_data->enable.p_sec_cback != NULL  )
    bta_dm_cb.p_sec_cback = p_data->enable.p_sec_cback;

-_-!这不就两个注册回调函数吗!?我们再回头看看

看来  bta_sys_sendmsg(sys_enable_event)才是处理,这个和之前分析的一样,我们只要找到BTA_SYS_API_ENABLE_EVT的值,再找到对应的注册,就可以知道在哪处理的了

enum
{
    /* device manager local device API events */
    BTA_SYS_API_ENABLE_EVT = BTA_SYS_EVT_START(BTA_ID_SYS),
    BTA_SYS_EVT_ENABLED_EVT,
    BTA_SYS_EVT_STACK_ENABLED_EVT,
    BTA_SYS_API_DISABLE_EVT,
    BTA_SYS_EVT_DISABLED_EVT,
    BTA_SYS_ERROR_EVT,

    BTA_SYS_MAX_EVT
};
现在可以搜索注册bta_sys_register(BTA_ID_SYS 了,在Bta_sys_main中找到了

void bta_sys_init(void)
{
    memset(&bta_sys_cb, 0, sizeof(tBTA_SYS_CB));

    pthread_mutex_init(&bta_alarm_lock, NULL);

    bta_alarm_hash_map = hash_map_new(BTA_ALARM_HASH_MAP_SIZE,
            hash_function_pointer, NULL, (data_free_fn)alarm_free, NULL);
    btu_bta_alarm_queue = fixed_queue_new(SIZE_MAX);

    fixed_queue_register_dequeue(btu_bta_alarm_queue,
        thread_get_reactor(bt_workqueue_thread),
        btu_bta_alarm_ready,
        NULL);

    appl_trace_level = APPL_INITIAL_TRACE_LEVEL;

    /* register BTA SYS message handler */
    bta_sys_register( BTA_ID_SYS,  &bta_sys_hw_reg);

    /* register for BTM notifications */
    BTM_RegisterForDeviceStatusNotif ((tBTM_DEV_STATUS_CB*)&bta_sys_hw_btm_cback );

#if( defined BTA_AR_INCLUDED ) && (BTA_AR_INCLUDED == TRUE)
    bta_ar_init();
#endif

}

static const tBTA_SYS_REG bta_sys_hw_reg =
{
    bta_sys_sm_execute,
    NULL
};

BOOLEAN bta_sys_sm_execute(BT_HDR *p_msg)
{
    BOOLEAN freebuf = TRUE;
    tBTA_SYS_ST_TBL      state_table;
    UINT8               action;
    int                 i;

    APPL_TRACE_EVENT("bta_sys_sm_execute state:%d, event:0x%x",  bta_sys_cb.state, p_msg->event);

    /* look up the state table for the current state */
    state_table = bta_sys_st_tbl[bta_sys_cb.state];
    /* update state */
    bta_sys_cb.state = state_table[p_msg->event & 0x00ff][BTA_SYS_NEXT_STATE];

    /* execute action functions */
    for (i = 0; i < BTA_SYS_ACTIONS; i++)
    {
        if ((action = state_table[p_msg->event & 0x00ff][i]) != BTA_SYS_IGNORE)
        {
            (*bta_sys_action[action])( (tBTA_SYS_HW_MSG*) p_msg);
        }
        else
        {
            break;
        }
    }
    return freebuf;

}

这里是状态模式了,状态模式的特点是不同状态响应命令有不同操作。首先BTA_ID_SYS=0,所以BTA_SYS_API_ENABLE_EVT=0<<8=0;

bta_sys_cb.state=bta_sys_hw_off,所以state_table = bta_sys_st_tbl[bta_sys_cb.state]

--》state_table = 
const UINT8 bta_sys_hw_off[][BTA_SYS_NUM_COLS] =
{
/* Event                    Action 1               Action 2             Next State */
/* API_ENABLE    */  {BTA_SYS_HW_API_ENABLE,    BTA_SYS_IGNORE,     BTA_SYS_HW_STARTING},
/* EVT_ENABLED   */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_STARTING},
/* STACK_ENABLED */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_ON},
/* API_DISABLE   */  {BTA_SYS_HW_EVT_DISABLED,  BTA_SYS_IGNORE,     BTA_SYS_HW_OFF},
/* EVT_DISABLED  */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_OFF},
/* EVT_ERROR     */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_OFF}
};

bta_sys_cb.state = state_table[p_msg->event & 0x00ff][BTA_SYS_NEXT_STATE]——》bta_sys_cb.state =BTA_SYS_HW_STARTING,下个状态是starting,进入循环,state_table【0】【0】=BTA_SYS_HW_API_ENABLE(下一次循环就break了),所以执行bta_sys_hw_api_enable

附:

/* state table */
const tBTA_SYS_ST_TBL bta_sys_st_tbl[] = {
    bta_sys_hw_off,
    bta_sys_hw_starting,
    bta_sys_hw_on,
    bta_sys_hw_stopping
};
/* state table for OFF state */
const UINT8 bta_sys_hw_off[][BTA_SYS_NUM_COLS] =
{
/* Event                    Action 1               Action 2             Next State */
/* API_ENABLE    */  {BTA_SYS_HW_API_ENABLE,    BTA_SYS_IGNORE,     BTA_SYS_HW_STARTING},
/* EVT_ENABLED   */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_STARTING},
/* STACK_ENABLED */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_ON},
/* API_DISABLE   */  {BTA_SYS_HW_EVT_DISABLED,  BTA_SYS_IGNORE,     BTA_SYS_HW_OFF},
/* EVT_DISABLED  */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_OFF},
/* EVT_ERROR     */  {BTA_SYS_IGNORE,           BTA_SYS_IGNORE,     BTA_SYS_HW_OFF}
};

const UINT8 bta_sys_hw_starting[][BTA_SYS_NUM_COLS] =
{
/* Event                    Action 1                   Action 2               Next State */
/* API_ENABLE    */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_STARTING}, /* wait for completion event */
/* EVT_ENABLED   */  {BTA_SYS_HW_EVT_ENABLED,       BTA_SYS_IGNORE,         BTA_SYS_HW_STARTING},
/* STACK_ENABLED */  {BTA_SYS_HW_EVT_STACK_ENABLED, BTA_SYS_IGNORE,         BTA_SYS_HW_ON},
/* API_DISABLE   */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_STOPPING}, /* successive disable/enable: change state wait for completion to disable */
/* EVT_DISABLED  */  {BTA_SYS_HW_EVT_DISABLED,      BTA_SYS_HW_API_ENABLE,  BTA_SYS_HW_STARTING}, /* successive enable/disable: notify, then restart HW */
/* EVT_ERROR */      {BTA_SYS_HW_ERROR,             BTA_SYS_IGNORE,         BTA_SYS_HW_ON}
};

const UINT8 bta_sys_hw_on[][BTA_SYS_NUM_COLS] =
{
/* Event                    Action 1                   Action 2               Next State */
/* API_ENABLE    */  {BTA_SYS_HW_API_ENABLE,        BTA_SYS_IGNORE,         BTA_SYS_HW_ON},
/* EVT_ENABLED   */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_ON},
/* STACK_ENABLED */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_ON},
/* API_DISABLE   */  {BTA_SYS_HW_API_DISABLE,       BTA_SYS_IGNORE,         BTA_SYS_HW_ON}, /* don't change the state here, as some other modules might be active */
/* EVT_DISABLED */   {BTA_SYS_HW_ERROR,             BTA_SYS_IGNORE,         BTA_SYS_HW_ON},
/* EVT_ERROR */      {BTA_SYS_HW_ERROR,             BTA_SYS_IGNORE,         BTA_SYS_HW_ON}
};

const UINT8 bta_sys_hw_stopping[][BTA_SYS_NUM_COLS] =
{
/* Event                    Action 1                   Action 2               Next State */
/* API_ENABLE    */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_STARTING}, /* change state, and wait for completion event to enable */
/* EVT_ENABLED   */  {BTA_SYS_HW_EVT_ENABLED,       BTA_SYS_IGNORE,         BTA_SYS_HW_STOPPING}, /* successive enable/disable: finish the enable before disabling */
/* STACK_ENABLED */  {BTA_SYS_HW_EVT_STACK_ENABLED, BTA_SYS_HW_API_DISABLE, BTA_SYS_HW_STOPPING}, /* successive enable/disable: notify, then stop */
/* API_DISABLE   */  {BTA_SYS_IGNORE,               BTA_SYS_IGNORE,         BTA_SYS_HW_STOPPING}, /* wait for completion event */
/* EVT_DISABLED  */  {BTA_SYS_HW_EVT_DISABLED,      BTA_SYS_IGNORE,         BTA_SYS_HW_OFF},
/* EVT_ERROR     */  {BTA_SYS_HW_API_DISABLE,       BTA_SYS_IGNORE,         BTA_SYS_HW_STOPPING}
};

我们看下bta_sys_hw_api_enable方法


/*******************************************************************************
**
** Function         bta_sys_hw_enable
**
** Description     this function is called after API enable and HW has been turned on
**
**
** Returns          success or failure
**
*******************************************************************************/

void bta_sys_hw_api_enable( tBTA_SYS_HW_MSG *p_sys_hw_msg )
{
    if ((!bta_sys_cb.sys_hw_module_active) && (bta_sys_cb.state != BTA_SYS_HW_ON))
    {
        /* register which HW module was turned on */
        bta_sys_cb.sys_hw_module_active |=  ((UINT32)1 << p_sys_hw_msg->hw_module );

        tBTA_SYS_HW_MSG *p_msg;
        if ((p_msg = (tBTA_SYS_HW_MSG *) GKI_getbuf(sizeof(tBTA_SYS_HW_MSG))) != NULL)
        {
            p_msg->hdr.event = BTA_SYS_EVT_ENABLED_EVT;
            p_msg->hw_module = p_sys_hw_msg->hw_module;

            bta_sys_sendmsg(p_msg);
        }
    }
    else
    {
        /* register which HW module was turned on */
        bta_sys_cb.sys_hw_module_active |=  ((UINT32)1 << p_sys_hw_msg->hw_module );

        /* HW already in use, so directly notify the caller */
        if (bta_sys_cb.sys_hw_cback[p_sys_hw_msg->hw_module ]!= NULL )
            bta_sys_cb.sys_hw_cback[p_sys_hw_msg->hw_module ](  BTA_SYS_HW_ON_EVT   );
    }

    APPL_TRACE_EVENT ("bta_sys_hw_api_enable for %d, active modules 0x%04X",
                    p_sys_hw_msg->hw_module, bta_sys_cb.sys_hw_module_active);

}
-_-!这注释不是说已经打开了吗,莫非这状态机是为了回调,之前已经打开了?

网上查了很多,发现漏了一个很重要的地方,在bte_main.c的bte_main_enable()方法中,有句module_start_up(get_module(HCI_MODULE)),这个HCI_MODULE就是hci_layer.c,再看看module_start_up()方法,

bool module_start_up(const module_t *module) {
  assert(metadata != NULL);
  assert(module != NULL);
  // TODO(zachoverflow): remove module->init check once automagic order/call is in place.
  // This hack is here so modules which don't require init don't have to have useless calls
  // as we're converting the startup sequence.
  assert(get_module_state(module) == MODULE_STATE_INITIALIZED || module->init == NULL);

  if (!call_lifecycle_function(module->start_up)) {
    LOG_ERROR("%s failed to start up \"%s\"", __func__, module->name);
    return false;
  }

  set_module_state(module, MODULE_STATE_STARTED);
  return true;
}
会调用modle的start_up方法

static future_t *start_up(void) {
 ......

  packet_fragmenter->init(&packet_fragmenter_callbacks);

  fixed_queue_register_dequeue(command_queue, thread_get_reactor(thread), event_command_ready, NULL);
  fixed_queue_register_dequeue(packet_queue, thread_get_reactor(thread), event_packet_ready, NULL);

  vendor->open(btif_local_bd_addr.address, &interface);
  hal->init(&hal_callbacks, thread);
  low_power_manager->init(thread);

  vendor->set_callback(VENDOR_CONFIGURE_FIRMWARE, firmware_config_callback);
  vendor->set_callback(VENDOR_CONFIGURE_SCO, sco_config_callback);
  vendor->set_callback(VENDOR_DO_EPILOG, epilog_finished_callback);

  if (!hci_inject->open(&interface)) {
    // TODO(sharvil): gracefully propagate failures from this layer.
  }

  int power_state = BT_VND_PWR_OFF;
#if (defined (BT_CLEAN_TURN_ON_DISABLED) && BT_CLEAN_TURN_ON_DISABLED == TRUE)
  LOG_WARN("%s not turning off the chip before turning on.", __func__);
  // So apparently this hack was needed in the past because a Wingray kernel driver
  // didn't handle power off commands in a powered off state correctly.

  // The comment in the old code said the workaround should be removed when the
  // problem was fixed. Sadly, I have no idea if said bug was fixed or if said
  // kernel is still in use, so we must leave this here for posterity. #sadpanda
#else
  // cycle power on the chip to ensure it has been reset
  vendor->send_command(VENDOR_CHIP_POWER_CONTROL, &power_state);
#endif
  power_state = BT_VND_PWR_ON;
  vendor->send_command(VENDOR_CHIP_POWER_CONTROL, &power_state);

  startup_future = future_new();
  LOG_DEBUG("%s starting async portion", __func__);
  thread_post(thread, event_finish_startup, NULL);
  return startup_future;
error:;
  shut_down(); // returns NULL so no need to wait for it
  return future_new_immediate(FUTURE_FAIL);
}
vendor->open调用vendor.c的vendor_open(),调用厂商的open接口,后面vendor->send_command应该是上电操作。

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转载自blog.csdn.net/ccc905341846/article/details/79009200