smu_get_datablock
int smu_get_datablock(struct smu_softc *sc, u_int8_t, u_int8_t *, size_t);
smu_get_datablock(sc, 0x18, data, sizeof data);
smu_get_datablock(sc, 0x21, data, sizeof data);
smu_get_datablock(sc, 0x78, data, sizeof data);