EDMA_CHAN_RX
sc->sc_edma_chan[EDMA_CHAN_RX] = be32toh(dmas[4]);
sc->sc_edma_chan[EDMA_CHAN_RX] = be32toh(dmas[5]);
sc->sc_edma_chan[EDMA_CHAN_RX] = -1;
const int rx_chan = sc->sc_edma_chan[EDMA_CHAN_RX];