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/*
* This file is part of the coreboot project.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <cpu/x86/tsc.h>
#include <pc80/i8254.h>
#include <smp/spinlock.h>
#include <delay.h>
#include <thread.h>
void init_timer(void)
{
(void)tsc_freq_mhz();
}
void udelay(unsigned int us)
{
unsigned long long start;
unsigned long long current;
unsigned long long clocks;
if (!thread_yield_microseconds(us))
return;
start = rdtscll();
clocks = us;
clocks *= tsc_freq_mhz();
current = rdtscll();
while ((current - start) < clocks) {
cpu_relax();
current = rdtscll();
}
}
#if CONFIG(TSC_MONOTONIC_TIMER)
#include <timer.h>
static struct monotonic_counter {
int initialized;
struct mono_time time;
uint64_t last_value;
} mono_counter;
void timer_monotonic_get(struct mono_time *mt)
{
uint64_t current_tick;
uint64_t ticks_elapsed;
unsigned long ticks_per_usec;
if (!mono_counter.initialized) {
init_timer();
mono_counter.last_value = rdtscll();
mono_counter.initialized = 1;
}
current_tick = rdtscll();
ticks_elapsed = current_tick - mono_counter.last_value;
ticks_per_usec = tsc_freq_mhz();
/* Update current time and tick values only if a full tick occurred. */
if (ticks_elapsed >= ticks_per_usec) {
uint64_t usecs_elapsed;
usecs_elapsed = ticks_elapsed / ticks_per_usec;
mono_time_add_usecs(&mono_counter.time, (long)usecs_elapsed);
mono_counter.last_value = current_tick;
}
/* Save result. */
*mt = mono_counter.time;
}
#endif
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