HawkView ISP library document for CMOS image tunning

Hi all:
I want to porting different CMOS sensor with Bayer RGB on A83T, so I want to know how the HawkView ISP library works. In A83T Linux kernel (drivers/media/video/sunxi-vfe/lib/libisp), there is a library but I cannot find any document about this library. Please tell me where to find the document.
Thank you
-Jack