2006-12-01 16:04:47 +08:00
|
|
|
/*
|
2007-02-05 18:42:07 +08:00
|
|
|
* linux/arch/arm/mach-at91/at91sam926x_time.c
|
2006-12-01 16:04:47 +08:00
|
|
|
*
|
|
|
|
* Copyright (C) 2005-2006 M. Amine SAYA, ATMEL Rousset, France
|
|
|
|
* Revision 2005 M. Nicolas Diremdjian, ATMEL Rousset, France
|
|
|
|
*
|
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
|
|
* published by the Free Software Foundation.
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/init.h>
|
|
|
|
#include <linux/interrupt.h>
|
|
|
|
#include <linux/irq.h>
|
|
|
|
#include <linux/kernel.h>
|
|
|
|
#include <linux/sched.h>
|
|
|
|
#include <linux/time.h>
|
|
|
|
|
|
|
|
#include <asm/hardware.h>
|
|
|
|
#include <asm/io.h>
|
|
|
|
#include <asm/mach/time.h>
|
|
|
|
|
|
|
|
#include <asm/arch/at91_pit.h>
|
|
|
|
|
|
|
|
|
|
|
|
#define PIT_CPIV(x) ((x) & AT91_PIT_CPIV)
|
|
|
|
#define PIT_PICNT(x) (((x) & AT91_PIT_PICNT) >> 20)
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Returns number of microseconds since last timer interrupt. Note that interrupts
|
|
|
|
* will have been disabled by do_gettimeofday()
|
|
|
|
* 'LATCH' is hwclock ticks (see CLOCK_TICK_RATE in timex.h) per jiffy.
|
|
|
|
*/
|
|
|
|
static unsigned long at91sam926x_gettimeoffset(void)
|
|
|
|
{
|
|
|
|
unsigned long elapsed;
|
|
|
|
unsigned long t = at91_sys_read(AT91_PIT_PIIR);
|
|
|
|
|
|
|
|
elapsed = (PIT_PICNT(t) * LATCH) + PIT_CPIV(t); /* hardware clock cycles */
|
|
|
|
|
2007-02-08 18:04:19 +08:00
|
|
|
return (unsigned long)(elapsed * jiffies_to_usecs(1)) / LATCH;
|
2006-12-01 16:04:47 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* IRQ handler for the timer.
|
|
|
|
*/
|
|
|
|
static irqreturn_t at91sam926x_timer_interrupt(int irq, void *dev_id)
|
|
|
|
{
|
|
|
|
volatile long nr_ticks;
|
|
|
|
|
|
|
|
if (at91_sys_read(AT91_PIT_SR) & AT91_PIT_PITS) { /* This is a shared interrupt */
|
|
|
|
/* Get number to ticks performed before interrupt and clear PIT interrupt */
|
|
|
|
nr_ticks = PIT_PICNT(at91_sys_read(AT91_PIT_PIVR));
|
|
|
|
do {
|
|
|
|
timer_tick();
|
|
|
|
nr_ticks--;
|
|
|
|
} while (nr_ticks);
|
|
|
|
|
|
|
|
return IRQ_HANDLED;
|
|
|
|
} else
|
|
|
|
return IRQ_NONE; /* not handled */
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct irqaction at91sam926x_timer_irq = {
|
|
|
|
.name = "at91_tick",
|
2007-05-08 15:35:39 +08:00
|
|
|
.flags = IRQF_SHARED | IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
|
2006-12-01 16:04:47 +08:00
|
|
|
.handler = at91sam926x_timer_interrupt
|
|
|
|
};
|
|
|
|
|
|
|
|
void at91sam926x_timer_reset(void)
|
|
|
|
{
|
|
|
|
/* Disable timer */
|
|
|
|
at91_sys_write(AT91_PIT_MR, 0);
|
|
|
|
|
|
|
|
/* Clear any pending interrupts */
|
|
|
|
(void) at91_sys_read(AT91_PIT_PIVR);
|
|
|
|
|
|
|
|
/* Set Period Interval timer and enable its interrupt */
|
|
|
|
at91_sys_write(AT91_PIT_MR, (LATCH & AT91_PIT_PIV) | AT91_PIT_PITIEN | AT91_PIT_PITEN);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Set up timer interrupt.
|
|
|
|
*/
|
|
|
|
void __init at91sam926x_timer_init(void)
|
|
|
|
{
|
|
|
|
/* Initialize and enable the timer */
|
|
|
|
at91sam926x_timer_reset();
|
|
|
|
|
|
|
|
/* Make IRQs happen for the system timer. */
|
|
|
|
setup_irq(AT91_ID_SYS, &at91sam926x_timer_irq);
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_PM
|
|
|
|
static void at91sam926x_timer_suspend(void)
|
|
|
|
{
|
|
|
|
/* Disable timer */
|
|
|
|
at91_sys_write(AT91_PIT_MR, 0);
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
#define at91sam926x_timer_suspend NULL
|
|
|
|
#endif
|
|
|
|
|
|
|
|
struct sys_timer at91sam926x_timer = {
|
|
|
|
.init = at91sam926x_timer_init,
|
|
|
|
.offset = at91sam926x_gettimeoffset,
|
|
|
|
.suspend = at91sam926x_timer_suspend,
|
|
|
|
.resume = at91sam926x_timer_reset,
|
|
|
|
};
|
|
|
|
|