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/*
* arch/arm/mach-iop13xx/time.c
*
* Timer code for IOP13xx (copied from IOP32x/IOP33x implementation)
*
* 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 <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
static unsigned long ticks_per_jiffy;
static unsigned long ticks_per_usec;
static unsigned long next_jiffy_time;
static inline u32 read_tcr1(void)
{
u32 val;
asm volatile("mrc p6, 0, %0, c3, c9, 0" : "=r" (val));
return val;
}
unsigned long iop13xx_gettimeoffset(void)
{
unsigned long offset;
u32 cp_flags;
cp_flags = iop13xx_cp6_save();
offset = next_jiffy_time - read_tcr1();
iop13xx_cp6_restore(cp_flags);
return offset / ticks_per_usec;
}
static irqreturn_t
iop13xx_timer_interrupt(int irq, void *dev_id)
{
u32 cp_flags = iop13xx_cp6_save();
write_seqlock(&xtime_lock);
asm volatile("mcr p6, 0, %0, c6, c9, 0" : : "r" (1));
while ((signed long)(next_jiffy_time - read_tcr1())
>= ticks_per_jiffy) {
timer_tick();
next_jiffy_time -= ticks_per_jiffy;
}
write_sequnlock(&xtime_lock);
iop13xx_cp6_restore(cp_flags);
return IRQ_HANDLED;
}
static struct irqaction iop13xx_timer_irq = {
.name = "IOP13XX Timer Tick",
.handler = iop13xx_timer_interrupt,
.flags = IRQF_DISABLED | IRQF_TIMER,
};
void __init iop13xx_init_time(unsigned long tick_rate)
{
u32 timer_ctl;
u32 cp_flags;
ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
ticks_per_usec = tick_rate / 1000000;
next_jiffy_time = 0xffffffff;
timer_ctl = IOP13XX_TMR_EN | IOP13XX_TMR_PRIVILEGED |
IOP13XX_TMR_RELOAD | IOP13XX_TMR_RATIO_1_1;
/*
* We use timer 0 for our timer interrupt, and timer 1 as
* monotonic counter for tracking missed jiffies.
*/
cp_flags = iop13xx_cp6_save();
asm volatile("mcr p6, 0, %0, c4, c9, 0" : : "r" (ticks_per_jiffy - 1));
asm volatile("mcr p6, 0, %0, c0, c9, 0" : : "r" (timer_ctl));
asm volatile("mcr p6, 0, %0, c5, c9, 0" : : "r" (0xffffffff));
asm volatile("mcr p6, 0, %0, c1, c9, 0" : : "r" (timer_ctl));
iop13xx_cp6_restore(cp_flags);
setup_irq(IRQ_IOP13XX_TIMER0, &iop13xx_timer_irq);
}
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