bus_space_mmap() for IO

[Manuel Bouyer]

Hello,
in sys/arch/mips/mips/bus_space_alignstride_chipdep.c, mmap() for I/O
space is not supported:
__BS(mmap)(void *v, bus_addr_t addr, off_t off, int prot, int flags)
{
#ifdef CHIP_IO

/* Not supported for I/O space. */
return (-1);

Is there any reason to not remove this limitation ? I need this for X11
on the lemote fuulong (which has a SIS 315Pro graphic controller).
With the attached patch (and some other changes :) I could get
xf86-video-sis working on the fuulong.

This patch also add PGC_NOCACHE unless BUS_SPACE_MAP_CACHEABLE is requested.
It's probably a bug to always map cacheable here.