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linux-next/arch/unicore32/kernel/time.c
GuanXuetao 02b2ee16cc unicore32 core architecture: timer and time handling
This patch implements timer and time.
RTC and PWM device drivers are also here.

Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
2011-03-17 09:19:10 +08:00

149 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. */
OST_OIER &= ~OST_OIER_E0;
OST_OSSR &= ~OST_OSSR_M0;
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;
OST_OIER |= OST_OIER_E0;
next = OST_OSCR + delta;
OST_OSMR0 = next;
oscr = OST_OSCR;
return (signed)(next - oscr) <= MIN_OSCR_DELTA ? -ETIME : 0;
}
static void
puv3_osmr0_set_mode(enum clock_event_mode mode, struct clock_event_device *c)
{
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
OST_OIER &= ~OST_OIER_E0;
OST_OSSR &= ~OST_OSSR_M0;
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
}
}
static struct clock_event_device ckevt_puv3_osmr0 = {
.name = "osmr0",
.features = CLOCK_EVT_FEAT_ONESHOT,
#ifdef CONFIG_ARCH_FPGA
.shift = 18, /* correct shift val: 16, but warn_on_slowpath */
#else
.shift = 30,
#endif
.rating = 200,
.set_next_event = puv3_osmr0_set_next_event,
.set_mode = puv3_osmr0_set_mode,
};
static cycle_t puv3_read_oscr(struct clocksource *cs)
{
return 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_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = puv3_ost0_interrupt,
.dev_id = &ckevt_puv3_osmr0,
};
void __init time_init(void)
{
OST_OIER = 0; /* disable any timer interrupts */
OST_OSSR = 0; /* clear status on all timers */
ckevt_puv3_osmr0.mult =
div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt_puv3_osmr0.shift);
ckevt_puv3_osmr0.max_delta_ns =
clockevent_delta2ns(0x7fffffff, &ckevt_puv3_osmr0);
ckevt_puv3_osmr0.min_delta_ns =
clockevent_delta2ns(MIN_OSCR_DELTA * 2, &ckevt_puv3_osmr0) + 1;
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] = OST_OSMR0;
osmr[1] = OST_OSMR1;
osmr[2] = OST_OSMR2;
osmr[3] = OST_OSMR3;
oier = OST_OIER;
}
void puv3_timer_resume(void)
{
OST_OSSR = 0;
OST_OSMR0 = osmr[0];
OST_OSMR1 = osmr[1];
OST_OSMR2 = osmr[2];
OST_OSMR3 = osmr[3];
OST_OIER = oier;
/*
* OSMR0 is the system timer: make sure OSCR is sufficiently behind
*/
OST_OSCR = OST_OSMR0 - LATCH;
}
#else
void puv3_timer_suspend(void) { };
void puv3_timer_resume(void) { };
#endif