I'm writing for an atmel at91sam9260 arm 9 cored single board computer [glomation gesbc9260]

Using request_mem_region(0xFFFFFC00,0x100,"name"); //port range runs from fc00 to fcff

that works fine and shows up in /proc/iomem

then i try to write to the last bit of the port at fc20 with

writel(0x1, 0xFFFFFC20);

and i segfault...specifically "unable to handle kernel paging request at virtual address fffffc20.

I'm of the mind that i'm not allocating the right memory space...

any helpful insight would be great...