related to Android audio driver

Question

Hi, there

While I was diving into the Android kernel. I had a question about audio device driver.

People say that... - Android uses ALSA audio driver. - HAL layer is C/C++ library - ALSA driver runs in user space, not in kernel space

Then, questions: 1. What is the Audio Drivers(I guess it's ALSA driver) in the picture below? ALSA driver should exist in the library portion, isn't it? (http://developer.android.com/guide/basics/what-is-android.html)

2. There should be nothing about audio driver in Android Kernel, if it conforms to the ALSA driver?

1. I have a wm8994.c codec source file which drives codec h/w actually. who's going to call the functions in wm8994.c? I think ALSA HAL will. Am I wrong?

I'm very confused...

Thank you ilgimae