TWS_I2O0_CTL
reg = tws_read_reg(sc, TWS_I2O0_CTL, 4);
TWS_TRACE_DEBUG(sc, "i20 ctl", reg, TWS_I2O0_CTL);
tws_write_reg(sc, TWS_I2O0_CTL, reg | TWS_BIT1, 4);
TWS_TRACE_DEBUG(sc, "dma_mem_phys", sc->dma_mem_phys, TWS_I2O0_CTL);