a2dp
dfsdfsd
\external\bluetooth\bluedroid\audio_a2dp_hw\audio_a2dp_hw.cpp
编译生成audio.a2dp.default.so，主要实现a2dp做为设备的功能
struct audio_module HAL_MODULE_INFO_SYM = {
.common = {
.tag = HARDWARE_MODULE_TAG,
.version_major = 1,
.version_minor = 0,
.id = AUDIO_HARDWARE_MODULE_ID,
.name = "A2DP Audio HW HAL",
.author = "The Android Open Source Project",
.methods = &hal_module_methods,
},
};
\hardware\libhardware_legacy\audio\audio_policy_hal.cpp
编译生成libaudiohw_legacy.so,是audio_policy的HAL层，不同厂商可以有自己的audio_policy。
struct legacy_ap_module HAL_MODULE_INFO_SYM = {
module: {
common: {
tag: HARDWARE_MODULE_TAG,
version_major: 1,
version_minor: 0,
id: AUDIO_POLICY_HARDWARE_MODULE_ID,
name: "LEGACY Audio Policy HAL",
author: "The Android Open Source Project",
methods: &legacy_ap_module_methods,
dso : NULL,
reserved : {0},
},
},
};
audio_policy.conf
该文件最后放在/system/etc/ 下，其定义了系统的音频设备，其中AUDIO_HARDWARE_MODULE_ID =“a2dp”,AudioPolicyService中的load_audio_interface根据AUDIO_HARDWARE_MODULE_ID来加载对应的audio库。
audio_hw_modules {
primary {
outputs {
primary {
sampling_rates 44100
channel_masks AUDIO_CHANNEL_OUT_STEREO
formats AUDIO_FORMAT_PCM_16_BIT
devices AUDIO_DEVICE_OUT_EARPIECE|AUDIO_DEVICE_OUT_SPEAKER|AUDIO_DEVICE_OUT_WIRED_HEADSET|AUDIO_DEVICE_OUT_WIRED_HEADPHONE|AUDIO_DEVICE_OUT_ALL_SCO|AUDIO_DEVICE_OUT_AUX_DIGITAL|AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET
flags AUDIO_OUTPUT_FLAG_PRIMARY
}
}
inputs {
primary {
sampling_rates 8000|11025|16000|22050|32000|44100|48000
channel_masks AUDIO_CHANNEL_IN_MONO|AUDIO_CHANNEL_IN_STEREO
formats AUDIO_FORMAT_PCM_16_BIT
devices AUDIO_DEVICE_IN_BUILTIN_MIC|AUDIO_DEVICE_IN_BLUETOOTH_SCO_HEADSET|AUDIO_DEVICE_IN_WIRED_HEADSET
}
}
}
a2dp {
outputs {
a2dp {
sampling_rates 44100
channel_masks AUDIO_CHANNEL_OUT_STEREO
formats AUDIO_FORMAT_PCM_16_BIT
devices AUDIO_DEVICE_OUT_ALL_A2DP
}
}
}
}
下图是一张a2dp模块初始化的流程，其主要是加载了a2dp的audio库，并audio policy中注册了一个a2dp音频设备：
BluetoothManagerService绑定IBluetooth过程
public void getNameAndAddress() {
if (DBG) {
Log.d(TAG,"getNameAndAddress(): mBluetooth = " + mBluetooth +
" mBinding = " + mBinding);
}
Message msg = mHandler.obtainMessage(MESSAGE_GET_NAME_AND_ADDRESS);
mHandler.sendMessage(msg);
}
BluetoothHandler::handleMessage
case MESSAGE_GET_NAME_AND_ADDRESS: {
if (DBG) Log.d(TAG,"MESSAGE_GET_NAME_AND_ADDRESS");
synchronized(mConnection) {
//Start bind request
if ((mBluetooth == null) && (!mBinding)) {
if (DBG) Log.d(TAG, "Binding to service to get name and address");
mConnection.setGetNameAddressOnly(true);
//Start bind timeout and bind
Message timeoutMsg = mHandler.obtainMessage(MESSAGE_TIMEOUT_BIND);
mHandler.sendMessageDelayed(timeoutMsg,TIMEOUT_BIND_MS);
Intent i = new Intent(IBluetooth.class.getName());
if (!mContext.bindService(i, mConnection,
Context.BIND_AUTO_CREATE, UserHandle.USER_CURRENT)) {
mHandler.removeMessages(MESSAGE_TIMEOUT_BIND);
Log.e(TAG, "fail to bind to: " + IBluetooth.class.getName());
} else {
mBinding = true;
}
}
在这里调用了bindService来绑定服务，成功后调用mConnection的onServiceConnected
private BluetoothServiceConnection mConnection = new BluetoothServiceConnection();
private class BluetoothServiceConnection implements ServiceConnection {
private boolean mGetNameAddressOnly;
public void setGetNameAddressOnly(boolean getOnly) {
mGetNameAddressOnly = getOnly;
}
public boolean isGetNameAddressOnly() {
return mGetNameAddressOnly;
}
public void onServiceConnected(ComponentName className, IBinder service) {
if (DBG) Log.d(TAG, "BluetoothServiceConnection: connected to AdapterService className:"+className+" service:",service);
Message msg = mHandler.obtainMessage(MESSAGE_BLUETOOTH_SERVICE_CONNECTED);
msg.obj = service;
mHandler.sendMessage(msg);
}
public void onServiceDisconnected(ComponentName className) {
// Called if we unexpected disconnected.
if (DBG) Log.d(TAG, "BluetoothServiceConnection: disconnected from AdapterService");
Message msg = mHandler.obtainMessage(MESSAGE_BLUETOOTH_SERVICE_DISCONNECTED);
mHandler.sendMessage(msg);
}
onServiceConnected调用完成后再次到
BluetoothHandler::handleMessage，处理打开BT的消息
以下是BluetoothAdapter的构造过程，向RemoteCallbackList中注册了一个IBluetoothManagerCallback，用来与BluetoothManagerService通信。
E:\BOX_4.2\frameworks\base\core\java\android\bluetooth\BluetoothAdapter.cpp
BluetoothAdapter(IBluetoothManager managerService) {
if (managerService == null) {
throw new IllegalArgumentException("bluetooth manager service is null");
}
try {
mService = managerService.registerAdapter(mManagerCallback);
} catch (RemoteException e) {Log.e(TAG, "", e);}
mManagerService = managerService;
mServiceRecordHandler = null;
if (DBG) Log.d(TAG, "BluetoothAdapter" + ": mService ="+mService+ ": mManagerService ="+mManagerService+
": mManagerCallback ="+mManagerCallback);
}
final private IBluetoothManagerCallback mManagerCallback = new IBluetoothManagerCallback.Stub() { public void onBluetoothServiceUp(IBluetooth bluetoothService) { if (VDBG) Log.d(TAG, "onBluetoothServiceUp: " + bluetoothService); synchronized (mManagerCallback) { mService = bluetoothService; for (IBluetoothManagerCallback cb : mProxyServiceStateCallbacks ){ try { if (cb != null) { cb.onBluetoothServiceUp(bluetoothService); } else { Log.d(TAG, "onBluetoothServiceUp: cb is null!!!"); } } catch (Exception e) { Log.e(TAG,"",e);} } } }
public void onBluetoothServiceDown() { if (VDBG) Log.d(TAG, "onBluetoothServiceDown: " + mService); synchronized (mManagerCallback) { mService = null; for (IBluetoothManagerCallback cb : mProxyServiceStateCallbacks ){ try { if (cb != null) { cb.onBluetoothServiceDown(); } else { Log.d(TAG, "onBluetoothServiceDown: cb is null!!!"); } } catch (Exception e) { Log.e(TAG,"",e);} } } } }
\frameworks\base\services\java\com\android\server\BluetoothManagerService.cpp
public IBluetooth registerAdapter(IBluetoothManagerCallback callback){
Message msg = mHandler.obtainMessage(MESSAGE_REGISTER_ADAPTER);
msg.obj = callback;
mHandler.sendMessage(msg);
if (DBG) Log.d(TAG,"registerAdapter start");
synchronized(mConnection) {
if (DBG) Log.d(TAG,"registerAdapter end");
return mBluetooth;
}
}
BluetoothHandler-->handleMessage-->
case MESSAGE_REGISTER_ADAPTER:
{
IBluetoothManagerCallback callback = (IBluetoothManagerCallback) msg.obj;
boolean added = mCallbacks.register(callback);
}
最后注册到RemoteCallbackList中。
BT使能
BluetoothManagerService::
enable-->sendEnableMsg-->mHandler.sendMessage(mHandler.obtainMessage(MESSAGE_ENABLE,quietMode ? 1 : 0, 0)); BluetoothHandler handleMessage-->handleEnable(true)-->mBluetooth.registerCallback(mBluetoothCallback);
sendBluetoothServiceUpCallback();
mBluetooth.enable()
private final IBluetoothCallback mBluetoothCallback = new IBluetoothCallback.Stub() {
@Override
public void onBluetoothStateChange(int prevState, int newState) throws RemoteException {
Message msg = mHandler.obtainMessage(MESSAGE_BLUETOOTH_STATE_CHANGE,prevState,newState);
mHandler.sendMessage(msg);
}
};
mBluetoothCallback将消息交给BluetoothHandler的sendMessage来处理。
private void sendBluetoothServiceUpCallback() {
if (!mConnection.isGetNameAddressOnly()) {
int n = mCallbacks.beginBroadcast();
for (int i=0; i <n;i++) {
try {
mCallbacks.getBroadcastItem(i).onBluetoothServiceUp(mBluetooth);
} catch (RemoteException e) {
}
}
mCallbacks.finishBroadcast();
}
}
通知BluetoothAdapter，Adapter service is up
private void sendBluetoothServiceUpCallback() {
if (!mConnection.isGetNameAddressOnly()) {
int n = mCallbacks.beginBroadcast();
for (int i=0; i <n;i++) {
try {
mCallbacks.getBroadcastItem(i).onBluetoothServiceUp(mBluetooth);
} catch (RemoteException e) {
Log.e(TAG, "Unable to call onBluetoothServiceUp() on callback #" + i, e);
}
}
mCallbacks.finishBroadcast();
}
}
mCallbacks.getBroadcastItem(i)用来获取对对应IBluetoothManagerCallback，这是是指BluetoothAdapter::mManagerCallback,因此调用的是BluetoothAdapter的onBluetoothServiceUp：
public void onBluetoothServiceUp(IBluetooth bluetoothService) {
if (VDBG) Log.d(TAG, "onBluetoothServiceUp: " + bluetoothService);
synchronized (mManagerCallback) {
mService = bluetoothService;
for (IBluetoothManagerCallback cb : mProxyServiceStateCallbacks ){
try {
if (cb != null) {
cb.onBluetoothServiceUp(bluetoothService);
} else {
Log.d(TAG, "onBluetoothServiceUp: cb is null!!!");
}
} catch (Exception e) { Log.e(TAG,"",e);}
}
}
}
到此为止，还没有对BT硬件的操作，现在回到BluetoothManagerService的handleEnable，下一步调用了mBluetooth.enable()，最终是调用IBluetooth的enable。
以上我们只看到了IBluetooth的客户端代码，服务端在哪儿呢？看AdapterService的定义。
public class AdapterService extends Service{
static {
classInitNative();
}
private static class AdapterServiceBinder extends IBluetooth.Stub
}
classInitNative被声明成Native方法，直接调用com/android/bluetooth/btservice/AdapterService的classInitNative
\packages\apps\Bluetooth\jni\com_android_bluetooth_btservice_AdapterService.cpp
static void classInitNative(JNIEnv* env, jclass clazz) { int err; hw_module_t* module;
jclass jniCallbackClass = env->FindClass("com/android/bluetooth/btservice/JniCallbacks"); sJniCallbacksField = env->GetFieldID(clazz, "mJniCallbacks", "Lcom/android/bluetooth/btservice/JniCallbacks;");
method_stateChangeCallback = env->GetMethodID(jniCallbackClass, "stateChangeCallback", "(I)V");
method_adapterPropertyChangedCallback = env->GetMethodID(jniCallbackClass, "adapterPropertyChangedCallback", "([I[[B)V"); method_discoveryStateChangeCallback = env->GetMethodID(jniCallbackClass, "discoveryStateChangeCallback", "(I)V");
method_devicePropertyChangedCallback = env->GetMethodID(jniCallbackClass, "devicePropertyChangedCallback", "([B[I[[B)V"); method_deviceFoundCallback = env->GetMethodID(jniCallbackClass, "deviceFoundCallback", "([B)V"); method_pinRequestCallback = env->GetMethodID(jniCallbackClass, "pinRequestCallback", "([B[BI)V"); method_sspRequestCallback = env->GetMethodID(jniCallbackClass, "sspRequestCallback", "([B[BIII)V");
method_bondStateChangeCallback = env->GetMethodID(jniCallbackClass, "bondStateChangeCallback", "(I[BI)V");
method_aclStateChangeCallback = env->GetMethodID(jniCallbackClass, "aclStateChangeCallback", "(I[BI)V"); 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"); } }
这里主要是得到了sBluetoothInterface
AdapterService继承至Service，有一个内部类继承IBluetooth.Stub，这便是Bluetooth的服务端了。因此在AdapterService中必定有Bluetooth的服务端的具体实现。
AdapterServiceBinder::enable
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();
}
再看一下AdapterService的onCreate,这里调用了AdapterServiceBinder的构造
public void onCreate() {
super.onCreate();
mBinder = new AdapterServiceBinder(this);
mAdapterProperties = new AdapterProperties(this);
mAdapterStateMachine = AdapterState.make(this, mAdapterProperties);
mJniCallbacks = new JniCallbacks(mAdapterStateMachine, mAdapterProperties);
initNative();
mNativeAvailable=true;
mCallbacks = new RemoteCallbackList<IBluetoothCallback>();
//Load the name and address
getAdapterPropertyNative(AbstractionLayer.BT_PROPERTY_BDADDR);
getAdapterPropertyNative(AbstractionLayer.BT_PROPERTY_BDNAME);
}
service.enable()的的service是AdapterService，下一步是AdapterService的enable
public synchronized boolean enable(boolean quietMode) {
enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,
"Need BLUETOOTH ADMIN permission");
if (DBG)debugLog("Enable called with quiet mode status = " + mQuietmode);
mQuietmode = quietMode;
Message m =
mAdapterStateMachine.obtainMessage(AdapterState.USER_TURN_ON);
mAdapterStateMachine.sendMessage(m);
return true;
}
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mAdapterStateMachine.sendMessage(m)
状态转换：
OffState::USER_TURN_ON ---> processMessage::STARTED ---> processMessage::ENABLED_READY
在processMessage::STARTED 状态时调用mAdapterService.enableNative--》调用JNI方法
static jboolean enableNative(JNIEnv* env, jobject obj) {
jboolean result = JNI_FALSE;
if (!sBluetoothInterface) return result;
int ret = sBluetoothInterface->enable();
result = (ret == BT_STATUS_SUCCESS) ? JNI_TRUE : JNI_FALSE;
return result;
}
struct hw_module_t HAL_MODULE_INFO_SYM = {
.tag = HARDWARE_MODULE_TAG,
.version_major = 1,
.version_minor = 0,
.id = BT_HARDWARE_MODULE_ID,
.name = "Bluetooth Stack",
.author = "The Android Open Source Project",
.methods = &bt_stack_module_methods
};
static int enable( void )
{
/* sanity check */
if (interface_ready() == FALSE)
return BT_STATUS_NOT_READY;
return btif_enable_bluetooth();
}
E:\BOX_4.2\external\bluetooth\bluedroid\btif\src\btif_core.c
bt_status_t btif_enable_bluetooth(void)
{
BTIF_TRACE_DEBUG0("BTIF ENABLE BLUETOOTH");
if (btif_core_state != BTIF_CORE_STATE_DISABLED)
{
ALOGD("not disabled\n");
return BT_STATUS_DONE;
}
btif_core_state = BTIF_CORE_STATE_ENABLING;
/* Create the GKI tasks and run them */
bte_main_enable(btif_local_bd_addr.address);
return BT_STATUS_SUCCESS;
}
\external\bluetooth\bluedroid\main\bte_main.c
bte_main_enable-->bt_hc_if->set_power
bt_hc_if是HCI层接口
\external\bluetooth\bluedroid\hci\src\bt_hci_bdroid.c
static const bt_hc_interface_t bluetoothHCLibInterface = {
sizeof(bt_hc_interface_t),
init,
set_power,
lpm,
preload,
postload,
transmit_buf,
set_rxflow,
logging,
cleanup
};
