sc_cdaddr
cdmac_rx_start(sc, sc->sc_cdaddr + TEMAC_RXDOFF(0));
cdmac_tx_start(sc, sc->sc_cdaddr + TEMAC_TXDOFF(sc->sc_txreap));
sc->sc_txdescs[i].desc_next = sc->sc_cdaddr +
sc->sc_rxdescs[i].desc_next = sc->sc_cdaddr +
cdmac_rx_start(sc, sc->sc_cdaddr + TEMAC_RXDOFF(0));