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/*
* arch/ubicom32/kernel/timer_tick.c
* Impelemets a perodic timer.
*
* (C) Copyright 2009, Ubicom, Inc.
* Copyright (C) 1991, 1992, 1995 Linus Torvalds
*
* This file is part of the Ubicom32 Linux Kernel Port.
*
* The Ubicom32 Linux Kernel Port 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.
*
* The Ubicom32 Linux Kernel Port is distributed in the hope that it
* will be useful, but WITHOUT ANY WARRANTY; without even the implied
* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with the Ubicom32 Linux Kernel Port. If not,
* see <http://www.gnu.org/licenses/>.
*
* Ubicom32 implementation derived from (with many thanks):
* arch/m68knommu
* arch/blackfin
* arch/parisc
*/
#include <linux/profile.h>
#include <asm/ip5000.h>
#include <asm/machdep.h>
#if defined(CONFIG_SMP)
#include <asm/smp.h>
#endif
static unsigned int timervector;
static unsigned int frequency;
/*
* timer_tick()
* Kernel system timer support. Needs to keep up the real-time clock,
* as well as call the "do_timer()" routine every clocktick.
*/
static irqreturn_t timer_tick(int irq, void *dummy)
{
int ticks;
BUG_ON(!irqs_disabled());
ticks = timer_reset(timervector, frequency);
write_seqlock(&xtime_lock);
do_timer(ticks);
write_sequnlock(&xtime_lock);
update_process_times(user_mode(get_irq_regs()));
profile_tick(CPU_PROFILING);
#if defined(CONFIG_SMP)
smp_send_timer_all();
#endif
return(IRQ_HANDLED);
}
/*
* Data used by setup_irq for the timer.
*/
static struct irqaction timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = timer_tick,
};
/*
* timer_tick_init()
* Implements a periodic timer
*
* This implementation directly calls the timer_tick() and move
* the Linux kernel forward. This is used when the user has not
* selected GENERIC_CLOCKEVENTS.
*/
void timer_tick_init(void)
{
/*
* Now allocate a timer to ourselves.
*/
timervector = timer_alloc();
if (timervector == -1) {
printk(KERN_WARNING "where did the timer go?\n");
return;
}
setup_irq(timervector, &timer_irq);
/*
* Get the frequency from the processor device tree node or use
* the default if not available. We will store this as the frequency
* of the timer to avoid future calculations.
*/
frequency = processor_frequency();
if (frequency == 0) {
frequency = CLOCK_TICK_RATE;
}
frequency /= CONFIG_HZ;
printk(KERN_NOTICE "timer will interrupt every: %d cycles\n", frequency);
timer_set(timervector, frequency);
}
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