1. App/UI part
packages/apps/Bluetooth (bpp,findme,ftp,map,opp,pbap,proximity, thermometer)
packages/apps/Settings/src/com/android/settings/bluetooth
A2dpProfile.java,DUNProfile.java, HeadsetProfile.java, HidProfile.java, OppProfile.java, PanProfile.java, SapProfile.java,
LocalBluetoothProfile.java, LocalBluetoothProfileManager.java, BluetoothEnabler.java,BluetoothSettings.java,CachedBluetoothDevice.java
2. Frameworks/base part
frameworks/base/core/java/android/bluetooth
frameworks/base/core/java/android/server
(BluetoothA2dpService.java, BluetoothAdapterProperties.java, BluetoothAdapterStateMachine.java, BluetoothBondState.java
BluetoothDeviceProperties.java, BluetoothEventLoop.java, BluetoothGattProfileHandler.java,BluetoothHealthProfileHandler.java,
BluetoothInputProfileHandler.java, BluetoothPanProfileHandler.java, BluetoothService.java)
frameworks/base/core/jni
(android_bluetooth_*.c, android_server_BluetoothService.cpp, android_server_BluetoothEventLoop.cpp, android_server_BluetoothA2dpService.cpp)
3. Native C part
system/bluetooth
external/bluetooth/bluez
#define LOG_TAG "A2DP"
#define LOG_NDEBUG 0
#include <utils/Log.h>
4. Kernel part
kernel/net/bluetooth
(hci_core.c,hci_event.c,l2cap_core.c, sco.c)
kernel/drivers/bluetooth/
bluetooth-power.c, bluesleep.c, btuart/sdio/usb/smd