bcm2835_rng_read4
val = bcm2835_rng_read4(sc, sc->conf->control_reg);
val = bcm2835_rng_read4(sc, sc->conf->status_reg);
val = bcm2835_rng_read4(sc, RNG_FF_THRES);
val = bcm2835_rng_read4(sc, sc->conf->intr_mask_reg);
mask = bcm2835_rng_read4(sc, sc->conf->intr_mask_reg);
ctrl = bcm2835_rng_read4(sc, sc->conf->control_reg);
ctrl = bcm2835_rng_read4(sc, sc->conf->control_reg);
hwcount = bcm2835_rng_read4(sc, sc->conf->count_reg);