Netsilicon's NS7520 port

[Shreeranganath Gupta B B V]

Hi ,
     I'm very new to this Freebsd and i would like to know is there any
source code which is ported to Netsilicon (Now called 'Digi') ARM7
controller NS7520. If it is already ported, please let me know where i can
get the source code and tool chain.
      If there is no port for this controller, please let me know which
version of the freebsd source code and toolchaing that i may need to take
start my work. If any body can give some initial steps to be followed for
starting this porting activity will be of great help.

Thanks in advance.
Regards
Gupta