FEC_NTXDESC
sc->sc_pa + FEC_TFIFO_DATA, FEC_NTXDESC, MCLBYTES, 4,
for (i = 0; i < FEC_NTXDESC; i++) {
for (i = 0; i < FEC_NTXDESC; i++) {
while (sc->sc_txbusy < FEC_NTXDESC) {
sc->sc_txnext = (idx + 1) % FEC_NTXDESC;
if (sc->sc_txbusy == FEC_NTXDESC)
sc->sc_txdirty = (idx + 1) % FEC_NTXDESC;
struct mbuf *sc_txmbuf[FEC_NTXDESC];
bus_dmamap_t sc_txmap[FEC_NTXDESC];