root/arch/mips/kernel/i8253.c

DEFINITIONS

1. timer_interrupt
2. setup_pit_timer
3. init_pit_clocksource

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * i8253.c  8253/PIT functions
   4  *
   5  */
   6 #include <linux/clockchips.h>
   7 #include <linux/i8253.h>
   8 #include <linux/export.h>
   9 #include <linux/smp.h>
  10 #include <linux/irq.h>
  11 
  12 #include <asm/time.h>
  13 
  14 static irqreturn_t timer_interrupt(int irq, void *dev_id)
  15 {
  16         i8253_clockevent.event_handler(&i8253_clockevent);
  17 
  18         return IRQ_HANDLED;
  19 }
  20 
  21 static struct irqaction irq0  = {
  22         .handler = timer_interrupt,
  23         .flags = IRQF_NOBALANCING | IRQF_TIMER,
  24         .name = "timer"
  25 };
  26 
  27 void __init setup_pit_timer(void)
  28 {
  29         clockevent_i8253_init(true);
  30         setup_irq(0, &irq0);
  31 }
  32 
  33 static int __init init_pit_clocksource(void)
  34 {
  35         if (num_possible_cpus() > 1 || /* PIT does not scale! */
  36             !clockevent_state_periodic(&i8253_clockevent))
  37                 return 0;
  38 
  39         return clocksource_i8253_init();
  40 }
  41 arch_initcall(init_pit_clocksource);