nes-proj/cpu/arm/at91sam7s/clock.c

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2009-07-11 14:22:45 +00:00
#include <sys/clock.h>
#include <sys/cc.h>
#include <sys/etimer.h>
#include <debug-uart.h>
#include <AT91SAM7S64.h>
#include <sys-interrupt.h>
#define PIV ((MCK/CLOCK_SECOND/16)-1)
static volatile clock_time_t current_clock = 0;
static volatile unsigned long current_seconds = 0;
static unsigned int second_countdown = CLOCK_SECOND;
static int pit_handler_func()
{
if (!(*AT91C_PITC_PISR & AT91C_PITC_PITS)) return 0; /* Check PIT
Interrupt */
current_clock++;
if(etimer_pending() && etimer_next_expiration_time() <= current_clock) {
etimer_request_poll();
/* dbg_printf("%d,%d\n", clock_time(),etimer_next_expiration_time ()); */
}
if (--second_countdown == 0) {
current_seconds++;
second_countdown = CLOCK_SECOND;
}
(void)*AT91C_PITC_PIVR;
return 1;
}
static SystemInterruptHandler pit_handler = {NULL, pit_handler_func};
void
clock_init()
{
sys_interrupt_append_handler(&pit_handler);
*AT91C_PITC_PIMR = (AT91C_PITC_PITIEN | /* PIT Interrupt Enable */
AT91C_PITC_PITEN | /* PIT Enable */
PIV);
sys_interrupt_enable();
}
clock_time_t
clock_time(void)
{
return current_clock;
}
/* The inner loop takes 4 cycles. The outer 5+SPIN_COUNT*4. */
#define SPIN_TIME 2 /* us */
#define SPIN_COUNT (((MCK*SPIN_TIME/1000000)-5)/4)
#ifndef __MAKING_DEPS__
void
clock_delay(unsigned int t)
{
#ifdef __THUMBEL__
asm volatile("1: mov r1,%2\n2:\tsub r1,#1\n\tbne 2b\n\tsub %0,#1\n\tbne 1b\n":"=l"(t):"0"(t),"l"(SPIN_COUNT));
#else
#error Must be compiled in thumb mode
#endif
}
unsigned long
clock_seconds(void)
{
return current_seconds;
}
#endif /* __MAKING_DEPS__ */