ipw_hdr
sizeof (struct ipw_hdr), NULL, BUS_DMA_NOWAIT);
sbd->bd->len = htole32(sizeof (struct ipw_hdr));
bus_dmamap_sync(sc->sc_dmat, shdr->map, 0, sizeof (struct ipw_hdr),
error = bus_dmamap_create(sc->sc_dmat, sizeof (struct ipw_hdr),
1, sizeof (struct ipw_hdr), 0, BUS_DMA_NOWAIT, &shdr->map);
struct ipw_hdr hdr;