SCA_DSR0
dsr = dmac_read_1(scp, SCA_DSR0);
dmac_write_1(scp, SCA_DSR0, dsr | SCA_DSR_DEWD);
sca_write_1(sc, SCA_DSR0 + SCA_DMAC_OFF_0, 0);
sca_write_1(sc, SCA_DSR0 + SCA_DMAC_OFF_1, 0);
dmac_write_1(scp, SCA_DSR0, 0); /* disable DMA */
dmac_write_1(scp, SCA_DSR0, SCA_DSR_DE);