[ECOS] Who have added PPP driver to ecos?

[joyee]

HI, all:

       I am  ready to  add PPP driver to our eCos to establish network
connection over Modem-serial-tcp/ip ,and I have modified the related 
source code 
provided in Linux.but I find it is a bit difficult for me  ,So  I want 
to know if anyone has done
it,  and  would like share me the source code of PPP or some related 
Documents.
and also welcome  any  advices !

  Many thanks in advance !