DW_IATU_VIEWPORT
return (DBI_RD4(sc, DW_IATU_VIEWPORT) == 0xFFFFFFFFU);
DBI_WR4(sc, DW_IATU_VIEWPORT, IATU_REGION_INDEX(~0U));
reg = DBI_RD4(sc, DW_IATU_VIEWPORT);
DBI_WR4(sc, DW_IATU_VIEWPORT, IATU_REGION_INDEX(i));
DBI_WR4(sc, DW_IATU_VIEWPORT, IATU_REGION_INDEX(idx));