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/*
* linux/arch/arm/mach-sa1100/time.c
*
* Copyright (C) 1998 Deborah Wallach.
* Twiddles (C) 1999 Hugo Fiennes <hugo@empeg.com>
*
* 2000/03/29 (C) Nicolas Pitre <nico@cam.org>
* Rewritten: big cleanup, much simpler, better HZ accuracy.
*
*/
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/timex.h>
#include <linux/clockchips.h>
#include <asm/mach/time.h>
#include <asm/hardware.h>
#define MIN_OSCR_DELTA 2
static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* Disarm the compare/match, signal the event. */
OIER &= ~OIER_E0;
OSSR = OSSR_M0;
c->event_handler(c);
return IRQ_HANDLED;
}
static int
sa1100_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
{
unsigned long flags, next, oscr;
raw_local_irq_save(flags);
OIER |= OIER_E0;
next = OSCR + delta;
OSMR0 = next;
oscr = OSCR;
raw_local_irq_restore(flags);
return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
static void
sa1100_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
{
unsigned long flags;
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
raw_local_irq_save(flags);
OIER &= ~OIER_E0;
OSSR = OSSR_M0;
raw_local_irq_restore(flags);
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
}
}
static struct clock_event_device ckevt_sa1100_osmr0 = {
.name = "osmr0",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.rating = 200,
.cpumask = CPU_MASK_CPU0,
.set_next_event = sa1100_osmr0_set_next_event,
.set_mode = sa1100_osmr0_set_mode,
};
static cycle_t sa1100_read_oscr(void)
{
return OSCR;
}
static struct clocksource cksrc_sa1100_oscr = {
.name = "oscr",
.rating = 200,
.read = sa1100_read_oscr,
.mask = CLOCKSOURCE_MASK(32),
.shift = 20,
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct irqaction sa1100_timer_irq = {
.name = "ost0",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = sa1100_ost0_interrupt,
.dev_id = &ckevt_sa1100_osmr0,
};
static void __init sa1100_timer_init(void)
{
OIER = 0; /* disable any timer interrupts */
OSSR = 0xf; /* clear status on all timers */
ckevt_sa1100_osmr0.mult =
div_sc(3686400, NSEC_PER_SEC, ckevt_sa1100_osmr0.shift);
ckevt_sa1100_osmr0.max_delta_ns =
clockevent_delta2ns(0x7fffffff, &ckevt_sa1100_osmr0);
ckevt_sa1100_osmr0.min_delta_ns =
clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_sa1100_osmr0) + 1;
cksrc_sa1100_oscr.mult =
clocksource_hz2mult(CLOCK_TICK_RATE, cksrc_sa1100_oscr.shift);
setup_irq(IRQ_OST0, &sa1100_timer_irq);
clocksource_register(&cksrc_sa1100_oscr);
clockevents_register_device(&ckevt_sa1100_osmr0);
}
#ifdef CONFIG_PM
unsigned long osmr[4], oier;
static void sa1100_timer_suspend(void)
{
osmr[0] = OSMR0;
osmr[1] = OSMR1;
osmr[2] = OSMR2;
osmr[3] = OSMR3;
oier = OIER;
}
static void sa1100_timer_resume(void)
{
OSSR = 0x0f;
OSMR0 = osmr[0];
OSMR1 = osmr[1];
OSMR2 = osmr[2];
OSMR3 = osmr[3];
OIER = oier;
/*
* OSMR0 is the system timer: make sure OSCR is sufficiently behind
*/
OSCR = OSMR0 - LATCH;
}
#else
#define sa1100_timer_suspend NULL
#define sa1100_timer_resume NULL
#endif
struct sys_timer sa1100_timer = {
.init = sa1100_timer_init,
.suspend = sa1100_timer_suspend,
.resume = sa1100_timer_resume,
};
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