aplsmc_send_cmd
int aplsmc_send_cmd(struct aplsmc_softc *, uint16_t, uint32_t, uint16_t);
aplsmc_send_cmd(sc, SMC_GET_SRAM_ADDR, 0, 0);
aplsmc_send_cmd(sc, SMC_GET_KEY_INFO,
aplsmc_send_cmd(sc, SMC_READ_KEY, key, len);
aplsmc_send_cmd(sc, SMC_WRITE_KEY, key, len);