Bluedroid: Handsfree Sound Decoding Source Code

I'm trying to find a place in cyanogenmod source code, where sound, received from handsfree during a call, is decoded before directing it to phone line. And I need help with it. As

Solution 1:

As I know SCO link data is not transfered through HCI interface in many Bluetooth controller chips. Most of these chips has a dedicated audio interface (like PCM/I2S etc.) and SCO data will be send to host through the interface. Host then receive SCO audio data and process them in its audio subsystem. You can refer to Android audio system related source files like audio manager/audio policy/audio HAL.