metalsvm/arch/x86/kernel/timer.c
2011-08-02 15:58:20 +02:00

135 lines
3.2 KiB
C

/*
* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
* RWTH Aachen University
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is part of MetalSVM.
*/
#include <metalsvm/stdio.h>
#include <metalsvm/string.h>
#include <metalsvm/tasks.h>
#include <metalsvm/time.h>
#include <metalsvm/processor.h>
#include <metalsvm/errno.h>
#include <asm/irq.h>
#include <asm/irqflags.h>
#include <asm/gdt.h>
#include <asm/tss.h>
#include <asm/vga.h>
/*
* This will keep track of how many ticks the system
* has been running for
*/
static volatile uint64_t timer_ticks __attribute__ ((aligned (CACHE_LINE))) = 0;
uint64_t get_clock_tick(void)
{
return timer_ticks;
}
int sys_times(struct tms* buffer, clock_t* clock)
{
if (BUILTIN_EXPECT(!buffer, 0))
return -EINVAL;
if (BUILTIN_EXPECT(!clock, 0))
return -EINVAL;
memset(buffer, 0x00, sizeof(struct tms));
*clock = buffer->tms_utime = (clock_t) ((timer_ticks - per_core(current_task)->start_tick) * CLOCKS_PER_SEC / TIMER_FREQ);
return 0;
}
/*
* Handles the timer. In this case, it's very simple: We
* increment the 'timer_ticks' variable every time the
* timer fires.
*/
static void timer_handler(struct state *s)
{
/* Increment our 'tick counter' */
#if MAX_CORES > 1
if (smp_id() == 0)
timer_ticks++;
#else
timer_ticks++;
#endif
/*
* Every TIMER_FREQ clocks (approximately 1 second), we will
* display a message on the screen
*/
/*if (timer_ticks % TIMER_FREQ == 0) {
vga_puts("One second has passed\n");
}*/
}
/*
* This will continuously loop until the given time has
* been reached
*/
void timer_wait(unsigned int ticks)
{
uint64_t eticks = timer_ticks + ticks;
while (timer_ticks < eticks) {
check_workqueues();
// recheck break condition
if (timer_ticks >= eticks)
break;
reschedule();
}
}
#define LATCH(f) ((CLOCK_TICK_RATE + f/2) / f)
/*
* Sets up the system clock by installing the timer handler
* into IRQ0
*/
int timer_init(void)
{
uint64_t start;
/*
* Installs 'timer_handler' for the PIC and APIC timer,
* only one handler will be later used.
*/
irq_install_handler(32, timer_handler);
irq_install_handler(123, timer_handler);
/*
* The Rock Creek processor doesn't posseess an tradional PIC.
* Therefore, we have not to configure the PIC timer.
*/
#ifndef CONFIG_ROCKCREEK
outportb(0x43, 0x34);
/* before we write to 0x40, we wait some time */
start = rdtsc();
while(rdtsc() - start < 1000000)
;
outportb(0x40, LATCH(TIMER_FREQ) & 0xFF); /* low byte */
/* before we write to 0x40, we wait some time */
start = rdtsc();
while(rdtsc() - start < 1000000)
;
outportb(0x40, LATCH(TIMER_FREQ) >> 8); /* high byte */
#endif
return 0;
}