PMU_PWRDN_CON
val = bus_space_read_4(fdtbus_bs_tag, pmu, PMU_PWRDN_CON);
bus_space_write_4(fdtbus_bs_tag, pmu, PMU_PWRDN_CON, val);
val = bus_space_read_4(fdtbus_bs_tag, pmu, PMU_PWRDN_CON);
bus_space_write_4(fdtbus_bs_tag, pmu, PMU_PWRDN_CON, val);