blob: be65e9c95ffdd7e26c9d2250d85169a002d33c96 [file] [log] [blame]
/*
* Copyright (c) 2008 Travis Geiselbrecht
*
* 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 <err.h>
#include <debug.h>
#include <sys/types.h>
#include <kernel/thread.h>
#include <platform/timer.h>
#include <platform/interrupts.h>
#include <platform/debug.h>
#include <platform/at91sam7.h>
#define FIXED_1KHZ_TIMER 0
static platform_timer_callback timer_func;
static volatile time_t ticks = 0;
#if FIXED_1KHZ_TIMER
static volatile int timer_interval;
static volatile int timer_downcount;
#else
static int timer_ms_per_tick;
#endif
time_t current_time(void)
{
return ticks;
}
static enum handler_return pit_irq_handler(void *arg)
{
AT91PIT *pit = AT91PIT_ADDR;
unsigned n = PIT_PICNT(pit->PIVR);
#if FIXED_1KHZ_TIMER
ticks += n;
timer_downcount -= n;
if(timer_downcount <= 0) {
timer_downcount = timer_interval;
return timer_func(0, ticks);
} else {
return INT_NO_RESCHEDULE;
}
#else
ticks += (n * timer_ms_per_tick);
return timer_func(0, ticks);
#endif
}
status_t platform_set_periodic_timer(platform_timer_callback callback,
void *arg, time_t interval)
{
unsigned n;
AT91PIT *pit = AT91PIT_ADDR;
n = AT91_MCK_MHZ / 16 / 1000;
dprintf(INFO, "timer: MCK=%dKHz, n=%d\n", AT91_MCK_MHZ / 1000, n);
enter_critical_section();
timer_func = callback;
#if FIXED_1KHZ_TIMER
timer_interval = interval;
timer_downcount = interval;
#else
timer_ms_per_tick = interval;
n *= interval;
#endif
pit->MR = PIT_PITEN | PIT_PITIEN | (n & 0xfffff);
register_int_handler(PID_SYSIRQ, pit_irq_handler, 0);
unmask_interrupt(PID_SYSIRQ);
exit_critical_section();
return NO_ERROR;
}