ALTERA_TIMER_PERIODH_REG  151 arch/nios2/kernel/time.c 	timer_writew(timer, period >> 16, ALTERA_TIMER_PERIODH_REG);
ALTERA_TIMER_PERIODH_REG  300 arch/nios2/kernel/time.c 	timer_writew(&nios2_cs.timer, USHRT_MAX, ALTERA_TIMER_PERIODH_REG);