void
hpet_init(void)
{
uint64_t reg;
uint64_t s1, s2;
int same = 0;
/* Disable the counter. */
reg = hpet_read(HPET_REG_CONFIG);
reg &= ~(HPET_LEG_RT_CNF|HPET_ENABLE_CNF);
hpet_write(HPET_REG_CONFIG, reg);
/* Reset the counter value. */
hpet_write(HPET_REG_COUNTER, 0);
/* Re-enable the counter. */
reg |= HPET_ENABLE_CNF;
hpet_write(HPET_REG_CONFIG, reg);
/* See whether the hardware actually works. */
s1 = hpet_read(HPET_REG_COUNTER);
for (;;) {
s2 = hpet_read(HPET_REG_COUNTER);
if (s1 != s2)
break;
if (++same == 1000)
panic("HPET timer missing");
}
}
static int hpet_set_state_periodic(struct clock_event_device *evt)
{
int cfg;
spin_lock(&hpet_lock);
pr_info("set clock event to periodic mode!\n");
/* stop counter */
hpet_stop_counter();
/* enables the timer0 to generate a periodic interrupt */
cfg = hpet_read(HPET_T0_CFG);
cfg &= ~HPET_TN_LEVEL;
cfg |= HPET_TN_ENABLE | HPET_TN_PERIODIC | HPET_TN_SETVAL |
HPET_TN_32BIT;
hpet_write(HPET_T0_CFG, cfg);
/* set the comparator */
hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL);
udelay(1);
hpet_write(HPET_T0_CMP, HPET_COMPARE_VAL);
/* start counter */
hpet_start_counter();
spin_unlock(&hpet_lock);
return 0;
}
static void hpet_stop_counter(void)
{
unsigned int cfg = hpet_read(HPET_CFG);
cfg &= ~HPET_CFG_ENABLE;
hpet_write(HPET_CFG, cfg);
}
static int hpet_set_state_shutdown(struct clock_event_device *evt)
{
int cfg;
spin_lock(&hpet_lock);
cfg = hpet_read(HPET_T0_CFG);
cfg &= ~HPET_TN_ENABLE;
hpet_write(HPET_T0_CFG, cfg);
spin_unlock(&hpet_lock);
return 0;
}
static int hpet_next_event(unsigned long delta,
struct clock_event_device *evt)
{
u32 cnt;
s32 res;
cnt = hpet_read(HPET_COUNTER);
cnt += (u32) delta;
hpet_write(HPET_T0_CMP, cnt);
res = (s32)(cnt - hpet_read(HPET_COUNTER));
return res < HPET_MIN_CYCLES ? -ETIME : 0;
}
static irqreturn_t hpet_irq_handler(int irq, void *data)
{
int is_irq;
struct clock_event_device *cd;
unsigned int cpu = smp_processor_id();
is_irq = hpet_read(HPET_STATUS);
if (is_irq & HPET_T0_IRS) {
/* clear the TIMER0 irq status register */
hpet_write(HPET_STATUS, HPET_T0_IRS);
cd = &per_cpu(hpet_clockevent_device, cpu);
cd->event_handler(cd);
return IRQ_HANDLED;
}
return IRQ_NONE;
}
static int hpet_set_state_oneshot(struct clock_event_device *evt)
{
int cfg;
spin_lock(&hpet_lock);
pr_info("set clock event to one shot mode!\n");
cfg = hpet_read(HPET_T0_CFG);
/*
* set timer0 type
* 1 : periodic interrupt
* 0 : non-periodic(oneshot) interrupt
*/
cfg &= ~HPET_TN_PERIODIC;
cfg |= HPET_TN_ENABLE | HPET_TN_32BIT;
hpet_write(HPET_T0_CFG, cfg);
spin_unlock(&hpet_lock);
return 0;
}
static void hpet_reset_counter(void)
{
hpet_write(HPET_COUNTER, 0);
hpet_write(HPET_COUNTER + 4, 0);
}