CAS_CDRXADDR
KASSERT((CAS_CDRXADDR(sc, 0) & 0x1fff) == 0);
(((uint64_t)CAS_CDRXADDR(sc,0)) >> 32));
bus_space_write_4(t, h, CAS_RX_DRING_PTR_LO, CAS_CDRXADDR(sc, 0));