read_c0_pwctl
write_c0_pwctl(read_c0_pwctl() | \
write_c0_pwctl(read_c0_pwctl() & \
write_c0_pwctl(read_c0_pwctl() &
write_c0_pwctl(read_c0_pwctl() &
pr_info("PWCtl : %0x\n", read_c0_pwctl());
pwctl = read_c0_pwctl();