ncr_dma_intr
add_sicallback((si_farg)ncr_dma_intr, (void *)cur_softc, 0);
rem_sicallback((si_farg)ncr_dma_intr);
add_sicallback((si_farg)ncr_dma_intr,
add_sicallback((si_farg)ncr_dma_intr, (void *)cur_softc, 0);
static void ncr_dma_intr(struct ncr_softc *);