x86: More accurate PIT frequency estimation (1193182Hz)

In practice this has no impact since variance between crystals will be
substantially greater than 1-2ppm. But we may as well be as accurate
as possible.

From: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
This commit is contained in:
Keir Fraser committed 2008-07-21 09:46:17 +01:00
1 parent 9829c9f3ec
commit d84cb0723c
3 files changed
+3 -3

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@@ -411,7 +411,7 @@ void __init init_IRQ(void)
apic_intr_init();
/* Set the clock to HZ Hz */
#define CLOCK_TICK_RATE 1193180 /* crystal freq (Hz) */
#define CLOCK_TICK_RATE 1193182 /* crystal freq (Hz) */
#define LATCH (((CLOCK_TICK_RATE)+(HZ/2))/HZ)
outb_p(0x34, PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */
outb_p(LATCH & 0xff, PIT_CH0); /* LSB */
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@@ -214,7 +214,7 @@ static struct irqaction irq0 = { timer_interrupt, "timer", NULL };
* Return processor ticks per second / CALIBRATE_FRAC.
*/
#define CLOCK_TICK_RATE 1193180 /* system crystal frequency (Hz) */
#define CLOCK_TICK_RATE 1193182 /* system crystal frequency (Hz) */
#define CALIBRATE_FRAC 20 /* calibrate over 50ms */
#define CALIBRATE_LATCH ((CLOCK_TICK_RATE+(CALIBRATE_FRAC/2))/CALIBRATE_FRAC)
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@@ -95,7 +95,7 @@ struct periodic_time {
};
#define PIT_FREQ 1193181
#define PIT_FREQ 1193182
#define PIT_BASE 0x40
typedef struct PITState {
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