ar_tx_status
struct ar_tx_status *ds;
ds = &((struct ar_tx_status *)sc->sc_txsring)[sc->sc_txscur];
size = AR9003_NTXSTATUS * sizeof(struct ar_tx_status);
AR9003_NTXSTATUS * sizeof(struct ar_tx_status));
memset(sc->sc_txsring, 0, AR9003_NTXSTATUS * sizeof(struct ar_tx_status));