wm_cdrxsync
wm_cdrxsync(rxq, idx, BUS_DMASYNC_PREREAD);
wm_cdrxsync(rxq, i,
wm_cdrxsync(rxq, start, BUS_DMASYNC_PREREAD | BUS_DMASYNC_PREWRITE);
static inline void wm_cdrxsync(struct wm_rxqueue *, int, int);