simple mmap problem on at91sam9263

[Phillip Liang]

Hi,
I am trying GPIO on at91sam9263 with 2.6.21.1 Kernel using uclibc 0.9.29.
The simple mmap always return -1. errno = 22, EINVAL.
How do I debug the problem?
thanks.

#define MAP_SIZE 4096UL
#define MAP_MASK (MAP_SIZE - 1)
#define AT91_SYS        0xFFFFE000


  map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, AT91_SYS & ~MAP_MASK);

the same error from :
 map_base = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0xffffe000);