int _bus_dmatag_subregion(bus_dma_tag_t tag,
bus_addr_t min_addr,
bus_addr_t max_addr,
bus_dma_tag_t *newtag,
int flags)
void _bus_dmatag_destroy(bus_dma_tag_t tag)
that allow a (normally broken/limited) device to restrict the bus address
range it can talk to. this is used by bce(4) to limit DMA addresses to
1GB range, the maximum the chip can address.
all this is from Yorick Hardy <yhardy@uj.ac.za> with input from several
people on tech-kern.
XXX: bus_dma(9) needs an update still.
4410329b87