EDMA_CHAN_TX
sc->sc_edma_chan[EDMA_CHAN_TX] = be32toh(dmas[1]);
sc->sc_edma_chan[EDMA_CHAN_TX] = be32toh(dmas[1]);
sc->sc_edma_chan[EDMA_CHAN_TX] = -1;
const int tx_chan = sc->sc_edma_chan[EDMA_CHAN_TX];