linux/arch/unicore32/kernel/time.c

137 lines
3.3 KiB
C

/*
* linux/arch/unicore32/kernel/time.c
*
* Code specific to PKUnity SoC and UniCore ISA
*
* Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
* Copyright (C) 2001-2010 Guan Xuetao
*
* 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/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/timex.h>
#include <linux/clockchips.h>
#include <mach/hardware.h>
#define MIN_OSCR_DELTA 2
static irqreturn_t puv3_ost0_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* Disarm the compare/match, signal the event. */
writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
c->event_handler(c);
return IRQ_HANDLED;
}
static int
puv3_osmr0_set_next_event(unsigned long delta, struct clock_event_device *c)
{
unsigned long next, oscr;
writel(readl(OST_OIER) | OST_OIER_E0, OST_OIER);
next = readl(OST_OSCR) + delta;
writel(next, OST_OSMR0);
oscr = readl(OST_OSCR);
return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
static int puv3_osmr0_shutdown(struct clock_event_device *evt)
{
writel(readl(OST_OIER) & ~OST_OIER_E0, OST_OIER);
writel(readl(OST_OSSR) & ~OST_OSSR_M0, OST_OSSR);
return 0;
}
static struct clock_event_device ckevt_puv3_osmr0 = {
.name = "osmr0",
.features = CLOCK_EVT_FEAT_ONESHOT,
.rating = 200,
.set_next_event = puv3_osmr0_set_next_event,
.set_state_shutdown = puv3_osmr0_shutdown,
.set_state_oneshot = puv3_osmr0_shutdown,
};
static u64 puv3_read_oscr(struct clocksource *cs)
{
return readl(OST_OSCR);
}
static struct clocksource cksrc_puv3_oscr = {
.name = "oscr",
.rating = 200,
.read = puv3_read_oscr,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static struct irqaction puv3_timer_irq = {
.name = "ost0",
.flags = IRQF_TIMER | IRQF_IRQPOLL,
.handler = puv3_ost0_interrupt,
.dev_id = &ckevt_puv3_osmr0,
};
void __init time_init(void)
{
writel(0, OST_OIER); /* disable any timer interrupts */
writel(0, OST_OSSR); /* clear status on all timers */
clockevents_calc_mult_shift(&ckevt_puv3_osmr0, CLOCK_TICK_RATE, 5);
ckevt_puv3_osmr0.max_delta_ns =
clockevent_delta2ns(0x7fffffff, &ckevt_puv3_osmr0);
ckevt_puv3_osmr0.max_delta_ticks = 0x7fffffff;
ckevt_puv3_osmr0.min_delta_ns =
clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_puv3_osmr0) + 1;
ckevt_puv3_osmr0.min_delta_ticks = MIN_OSCR_DELTA * 2;
ckevt_puv3_osmr0.cpumask = cpumask_of(0);
setup_irq(IRQ_TIMER0, &puv3_timer_irq);
clocksource_register_hz(&cksrc_puv3_oscr, CLOCK_TICK_RATE);
clockevents_register_device(&ckevt_puv3_osmr0);
}
#ifdef CONFIG_PM
unsigned long osmr[4], oier;
void puv3_timer_suspend(void)
{
osmr[0] = readl(OST_OSMR0);
osmr[1] = readl(OST_OSMR1);
osmr[2] = readl(OST_OSMR2);
osmr[3] = readl(OST_OSMR3);
oier = readl(OST_OIER);
}
void puv3_timer_resume(void)
{
writel(0, OST_OSSR);
writel(osmr[0], OST_OSMR0);
writel(osmr[1], OST_OSMR1);
writel(osmr[2], OST_OSMR2);
writel(osmr[3], OST_OSMR3);
writel(oier, OST_OIER);
/*
* OSMR0 is the system timer: make sure OSCR is sufficiently behind
*/
writel(readl(OST_OSMR0) - LATCH, OST_OSCR);
}
#else
void puv3_timer_suspend(void) { };
void puv3_timer_resume(void) { };
#endif