RSP_ENTRIES
if (txp_dma_malloc(sc, sizeof(struct txp_rsp_desc) * RSP_ENTRIES,
bzero(sc->sc_rspring_dma.dma_vaddr, sizeof(struct txp_rsp_desc) * RSP_ENTRIES);
sc->sc_rspring.size = RSP_ENTRIES * sizeof(struct txp_rsp_desc);