DMAC_DINT
dmac_reg_write(sc, DMAC_DINT, (1u << channel));
rv = dmac_reg_read(sc, DMAC_DINT);
dmac_reg_write(sc, DMAC_DINT,
dmac_reg_read(sc, DMAC_DINT) & DMAC_DINT_MASK);