mmap() device memory

After you made sure you've got the right device with the memory mappings you need, all you have to do is to call mmap() to map the device's memory to userspace.

The parameter offset of the mmap() call has a special meaning for UIO devices: It is used to select which mapping of your device you want to map. To map the memory of mapping N, you have to use N times the page size as your offset:

	offset = N * getpagesize();

N starts from zero, so if you've got only one memory range to map, set offset = 0. A drawback of this technique is that memory is always mapped beginning with its start address.