int register_refined_jiffies(long cycles_per_second)
{
u64 nsec_per_tick, shift_hz;
long cycles_per_tick;
refined_jiffies = clocksource_jiffies;
refined_jiffies.name = "refined-jiffies";
refined_jiffies.rating++;
/* Calc cycles per tick */
cycles_per_tick = (cycles_per_second + HZ/2)/HZ;
/* shift_hz stores hz<<8 for extra accuracy */
shift_hz = (u64)cycles_per_second << 8;
shift_hz += cycles_per_tick/2;
do_div(shift_hz, cycles_per_tick);
/* Calculate nsec_per_tick using shift_hz */
nsec_per_tick = (u64)NSEC_PER_SEC << 8;
nsec_per_tick += (u32)shift_hz/2;
do_div(nsec_per_tick, (u32)shift_hz);
refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT;
__clocksource_register(&refined_jiffies);
return 0;
}
/*
* Initialize the TOD clock and the CPU timer of
* the boot cpu.
*/
void __init time_init(void)
{
/* Reset time synchronization interfaces. */
stp_reset();
/* request the clock comparator external interrupt */
if (register_external_irq(EXT_IRQ_CLK_COMP, clock_comparator_interrupt))
panic("Couldn't request external interrupt 0x1004");
/* request the timing alert external interrupt */
if (register_external_irq(EXT_IRQ_TIMING_ALERT, timing_alert_interrupt))
panic("Couldn't request external interrupt 0x1406");
if (__clocksource_register(&clocksource_tod) != 0)
panic("Could not register TOD clock source");
/* Enable TOD clock interrupts on the boot cpu. */
init_cpu_timer();
/* Enable cpu timer interrupts on the boot cpu. */
vtime_init();
}
static int __init init_jiffies_clocksource(void)
{
return __clocksource_register(&clocksource_jiffies);
}
