void rthal_setup_8254_tsc(void)
{
unsigned long flags;
int count;
#ifdef CONFIG_IPIPE_CORE
if (cpu_has_tsc)
printk("Xenomai: your configuration has tsc disabled while "
"your cpu has a tsc\nYou would get better performances "
"by enabling tsc in kernel configuration.\n");
#endif
rthal_local_irq_save_hw(flags);
outb_p(0x0, PIT_MODE);
count = inb_p(PIT_CH0);
count |= inb_p(PIT_CH0) << 8;
outb_p(0xb4, PIT_MODE);
outb_p(RTHAL_8254_COUNT2LATCH & 0xff, PIT_CH2);
outb_p(RTHAL_8254_COUNT2LATCH >> 8, PIT_CH2);
rthal_tsc_8254 = count + LATCH * jiffies;
rthal_last_8254_counter2 = 0;
/* Gate high, disable speaker */
outb_p((inb_p(0x61) & ~0x2) | 1, 0x61);
rthal_local_irq_restore_hw(flags);
}
static void rthal_timer_set_oneshot(void)
{
unsigned long flags;
int count;
rthal_local_irq_save_hw(flags);
/*
* We should be running in rate generator mode (M2) on entry,
* so read the current latch value, in order to roughly
* restart the timing where we left it, after the switch to
* software strobe mode.
*/
outb_p(0x00, PIT_MODE);
count = inb_p(PIT_CH0);
count |= inb_p(PIT_CH0) << 8;
if (count > LATCH) /* For broken VIA686a hardware. */
count = LATCH - 1;
/*
* Force software triggered strobe mode (M4) on PIT channel
* #0. We also program an initial shot at a sane value to
* restart the timing cycle.
*/
udelay(10);
outb_p(0x38, PIT_MODE);
outb(count & 0xff, PIT_CH0);
outb(count >> 8, PIT_CH0);
rthal_local_irq_restore_hw(flags);
}
static void rthal_timer_set_periodic(void)
{
unsigned long flags;
rthal_local_irq_save_hw(flags);
outb_p(0x34, PIT_MODE);
outb(LATCH & 0xff, PIT_CH0);
outb(LATCH >> 8, PIT_CH0);
rthal_local_irq_restore_hw(flags);
}
rthal_time_t rthal_get_8254_tsc(void)
{
unsigned long flags;
int delta, count;
rthal_time_t t;
rthal_local_irq_save_hw(flags);
outb(0xd8, PIT_MODE);
count = inb(PIT_CH2);
delta = rthal_last_8254_counter2 - (count |= (inb(PIT_CH2) << 8));
rthal_last_8254_counter2 = count;
rthal_tsc_8254 += (delta > 0 ? delta : delta + RTHAL_8254_COUNT2LATCH);
t = rthal_tsc_8254;
rthal_local_irq_restore_hw(flags);
return t;
}
unsigned long rthal_timer_calibrate(void)
{
unsigned long flags;
rthal_time_t t, dt;
int i, count;
rthal_local_irq_save_hw(flags);
/* Read the current latch value, whatever the current mode is. */
outb_p(0x00, PIT_MODE);
count = inb_p(PIT_CH0);
count |= inb_p(PIT_CH0) << 8;
if (count > LATCH) /* For broken VIA686a hardware. */
count = LATCH - 1;
/*
* We only want to measure the average time needed to program
* the next shot, so we basically don't care about the current
* PIT mode. We just rewrite the original latch value at each
* iteration.
*/
t = rthal_rdtsc();
for (i = 0; i < 20; i++) {
outb(count & 0xff, PIT_CH0);
outb(count >> 8, PIT_CH0);
}
dt = rthal_rdtsc() - t;
rthal_local_irq_restore_hw(flags);
#ifdef CONFIG_IPIPE_TRACE_IRQSOFF
/* Reset the max trace, since it contains the calibration time now. */
rthal_trace_max_reset();
#endif /* CONFIG_IPIPE_TRACE_IRQSOFF */
return rthal_ulldiv(dt, i, NULL);
}
unsigned long rthal_timer_calibrate(void)
{
unsigned long flags, freq;
u64 t, v;
u32 d;
int n;
rthal_local_irq_save_hw(flags);
rthal_read_tsc(t);
barrier();
for (n = 1; n < 100; n++)
rthal_read_tsc(v);
rthal_local_irq_restore_hw(flags);
d = (u32)(v - t);
freq = rthal_get_clockfreq();
return ((1000000000 / freq) * (d / n));
}
