time.c
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/*
* arch/arm/plat-iop/time.c
*
* Timer code for IOP32x and IOP33x based systems
*
* Author: Deepak Saxena <dsaxena@mvista.com>
*
* Copyright 2002-2003 MontaVista Software Inc.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/init.h>
#include <linux/timex.h>
#include <linux/io.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/export.h>
#include <linux/sched_clock.h>
#include <mach/hardware.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#include <mach/time.h>
/*
* Minimum clocksource/clockevent timer range in seconds
*/
#define IOP_MIN_RANGE 4
/*
* IOP clocksource (free-running timer 1).
*/
static cycle_t notrace iop_clocksource_read(struct clocksource *unused)
{
return 0xffffffffu - read_tcr1();
}
static struct clocksource iop_clocksource = {
.name = "iop_timer1",
.rating = 300,
.read = iop_clocksource_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
/*
* IOP sched_clock() implementation via its clocksource.
*/
static u64 notrace iop_read_sched_clock(void)
{
return 0xffffffffu - read_tcr1();
}
/*
* IOP clockevents (interrupting timer 0).
*/
static int iop_set_next_event(unsigned long delta,
struct clock_event_device *unused)
{
u32 tmr = IOP_TMR_PRIVILEGED | IOP_TMR_RATIO_1_1;
BUG_ON(delta == 0);
write_tmr0(tmr & ~(IOP_TMR_EN | IOP_TMR_RELOAD));
write_tcr0(delta);
write_tmr0((tmr & ~IOP_TMR_RELOAD) | IOP_TMR_EN);
return 0;
}
static unsigned long ticks_per_jiffy;
static void iop_set_mode(enum clock_event_mode mode,
struct clock_event_device *unused)
{
u32 tmr = read_tmr0();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
write_tmr0(tmr & ~IOP_TMR_EN);
write_tcr0(ticks_per_jiffy - 1);
write_trr0(ticks_per_jiffy - 1);
tmr |= (IOP_TMR_RELOAD | IOP_TMR_EN);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* ->set_next_event sets period and enables timer */
tmr &= ~(IOP_TMR_RELOAD | IOP_TMR_EN);
break;
case CLOCK_EVT_MODE_RESUME:
tmr |= IOP_TMR_EN;
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
default:
tmr &= ~IOP_TMR_EN;
break;
}
write_tmr0(tmr);
}
static struct clock_event_device iop_clockevent = {
.name = "iop_timer0",
.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
.rating = 300,
.set_next_event = iop_set_next_event,
.set_mode = iop_set_mode,
};
static irqreturn_t
iop_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
write_tisr(1);
evt->event_handler(evt);
return IRQ_HANDLED;
}
static struct irqaction iop_timer_irq = {
.name = "IOP Timer Tick",
.handler = iop_timer_interrupt,
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.dev_id = &iop_clockevent,
};
static unsigned long iop_tick_rate;
unsigned long get_iop_tick_rate(void)
{
return iop_tick_rate;
}
EXPORT_SYMBOL(get_iop_tick_rate);
void __init iop_init_time(unsigned long tick_rate)
{
u32 timer_ctl;
sched_clock_register(iop_read_sched_clock, 32, tick_rate);
ticks_per_jiffy = DIV_ROUND_CLOSEST(tick_rate, HZ);
iop_tick_rate = tick_rate;
timer_ctl = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
/*
* Set up interrupting clockevent timer 0.
*/
write_tmr0(timer_ctl & ~IOP_TMR_EN);
write_tisr(1);
setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
iop_clockevent.cpumask = cpumask_of(0);
clockevents_config_and_register(&iop_clockevent, tick_rate,
0xf, 0xfffffffe);
/*
* Set up free-running clocksource timer 1.
*/
write_trr1(0xffffffff);
write_tcr1(0xffffffff);
write_tmr1(timer_ctl);
clocksource_register_hz(&iop_clocksource, tick_rate);
}