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/*
* Copyright (c) 2009 Corey Tabaka
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#include <sys/types.h>
#include <err.h>
#include <reg.h>
#include <debug.h>
#include <kernel/thread.h>
#include <kernel/spinlock.h>
#include <platform.h>
#include <platform/interrupts.h>
#include <platform/console.h>
#include <platform/timer.h>
#include <platform/pc.h>
#include "platform_p.h"
#include <arch/x86.h>
static platform_timer_callback t_callback;
static void *callback_arg;
static spin_lock_t lock;
static uint64_t next_trigger_time;
static uint64_t next_trigger_delta;
static uint64_t ticks_per_ms;
static uint64_t timer_delta_time;
static volatile uint64_t timer_current_time;
static uint16_t divisor;
#define INTERNAL_FREQ 1193182ULL
#define INTERNAL_FREQ_3X 3579546ULL
/* Maximum amount of time that can be program on the timer to schedule the next
* interrupt, in miliseconds */
#define MAX_TIMER_INTERVAL 55
status_t platform_set_periodic_timer(platform_timer_callback callback, void *arg, lk_time_t interval)
{
t_callback = callback;
callback_arg = arg;
next_trigger_delta = (uint64_t) interval << 32;
next_trigger_time = timer_current_time + next_trigger_delta;
return NO_ERROR;
}
lk_time_t current_time(void)
{
lk_time_t time;
// XXX slight race
time = (lk_time_t) (timer_current_time >> 32);
return time;
}
lk_bigtime_t current_time_hires(void)
{
lk_bigtime_t time;
// XXX slight race
time = (lk_bigtime_t) ((timer_current_time >> 22) * 1000) >> 10;
return time;
}
static enum handler_return os_timer_tick(void *arg)
{
uint64_t delta;
timer_current_time += timer_delta_time;
lk_time_t time = current_time();
//lk_bigtime_t btime = current_time_hires();
//printf_xy(71, 0, WHITE, "%08u", (uint32_t) time);
//printf_xy(63, 1, WHITE, "%016llu", (uint64_t) btime);
if (t_callback && timer_current_time >= next_trigger_time) {
delta = timer_current_time - next_trigger_time;
next_trigger_time = timer_current_time + next_trigger_delta - delta;
return t_callback(callback_arg, time);
} else {
return INT_NO_RESCHEDULE;
}
}
static void set_pit_frequency(uint32_t frequency)
{
uint32_t count, remainder;
/* figure out the correct divisor for the desired frequency */
if (frequency <= 18) {
count = 0xffff;
} else if (frequency >= INTERNAL_FREQ) {
count = 1;
} else {
count = INTERNAL_FREQ_3X / frequency;
remainder = INTERNAL_FREQ_3X % frequency;
if (remainder >= INTERNAL_FREQ_3X / 2) {
count += 1;
}
count /= 3;
remainder = count % 3;
if (remainder >= 1) {
count += 1;
}
}
divisor = count & 0xffff;
/*
* funky math that i don't feel like explaining. essentially 32.32 fixed
* point representation of the configured timer delta.
*/
timer_delta_time = (3685982306ULL * count) >> 10;
//dprintf(DEBUG, "set_pit_frequency: dt=%016llx\n", timer_delta_time);
//dprintf(DEBUG, "set_pit_frequency: divisor=%04x\n", divisor);
/*
* setup the Programmable Interval Timer
* timer 0, mode 2, binary counter, LSB followed by MSB
*/
outp(I8253_CONTROL_REG, 0x34);
outp(I8253_DATA_REG, divisor & 0xff); // LSB
outp(I8253_DATA_REG, divisor >> 8); // MSB
}
void platform_init_timer(void)
{
timer_current_time = 0;
ticks_per_ms = INTERNAL_FREQ/1000;
set_pit_frequency(1000); // ~1ms granularity
register_int_handler(INT_PIT, &os_timer_tick, NULL);
unmask_interrupt(INT_PIT);
}
void platform_halt_timers(void)
{
mask_interrupt(INT_PIT);
}
status_t platform_set_oneshot_timer(platform_timer_callback callback,
void *arg, lk_time_t interval)
{
uint32_t count;
spin_lock_saved_state_t state;
spin_lock_irqsave(&lock, state);
t_callback = callback;
callback_arg = arg;
if (interval > MAX_TIMER_INTERVAL)
interval = MAX_TIMER_INTERVAL;
if (interval < 1) interval = 1;
count = ticks_per_ms * interval;
divisor = count & 0xffff;
timer_delta_time = (3685982306ULL * count) >> 10;
/* Program PIT in teh software strobe configuration, to send one pulse
* after the count reach 0 */
outp(I8253_CONTROL_REG, 0x38);
outp(I8253_DATA_REG, divisor & 0xff); // LSB
outp(I8253_DATA_REG, divisor >> 8); // MSB
unmask_interrupt(INT_PIT);
spin_unlock_irqrestore(&lock, state);
return NO_ERROR;
}
void platform_stop_timer(void)
{
/* Enable interrupt mode that will stop the decreasing counter of the PIT */
outp(I8253_CONTROL_REG, 0x30);
return;
}
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