What types are the parameters of memcpy_toio?

[Roland Dreier <roland@topspin.com>]

This may be a silly question, but what are the types of the parameters
of memcpy_toio and memcpy_fromio?  I was under the impression that IO
addresses are "cookies" and not pointers, and hence should be kept as
unsigned long.

However, <asm-x86_64/io.h> declares them as

void *memcpy_fromio(void*,const void*,unsigned); 
void *memcpy_toio(void*,const void*,unsigned); 

which means my code (which uses unsigned long) gets warnings like

warning: passing arg 1 of `memcpy_toio' makes pointer from integer without a cast

Other architectures seem to expect the IO address to be unsigned long
and explicitly cast it to a pointer.

Thanks,
  Roland