IO address acess on L4linux for ARM

   IO peripheral Address region in my platform is 0xfffb0000 - 0xfffeffff    I want to add device driver in L4linux.    in L4linux device driver  ...  *(volatile unsigned char *)0xfffb0000 = 'c';  ...    following case made error result error e0 l4lx    | Invalid source for request: 2f.3f result error e0 l4lx    | Invalid source for request: 2f.3f result error e0 l4lx    | Invalid source for request: 2f.3f result error e0 l4lx    | Invalid source for request: 2f.3f result error e0 l4lx    | Invalid source for request: 2f.3f 0000003600000037 failed CLI: 0000000c.00000004    How can I access IO Address?