GENET_TX_DMA_PROD_INDEX
printf("TX PIDX = %08x\n", RD4(sc, GENET_TX_DMA_PROD_INDEX(qid)));
WR4(sc, GENET_TX_DMA_PROD_INDEX(qid), 0);
sc->sc_tx.queued = (RD4(sc, GENET_TX_DMA_PROD_INDEX(qid))
WR4(sc, GENET_TX_DMA_PROD_INDEX(qid), sc->sc_tx.pidx);