DMAC_REG_CCR
bus_space_write_1(dmac->sc_bst, chan->ch_bht, DMAC_REG_CCR, go);
DMAC_REG_CCR, DMAC_CCR_STR|DMAC_CCR_INT);
bus_space_write_1(dmac->sc_bst, chan->ch_bht, DMAC_REG_CCR,
bus_space_read_1(sc->sc_bst, chan->ch_bht, DMAC_REG_CCR),