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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 <asm/hardware.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>
#ifdef CONFIG_ARCH_IOP32X
#define IRQ_IOP3XX_TIMER0 IRQ_IOP321_TIMER0
#else
#ifdef CONFIG_ARCH_IOP33X
#define IRQ_IOP3XX_TIMER0 IRQ_IOP331_TIMER0
#endif
#endif
static unsigned long ticks_per_jiffy;
static unsigned long ticks_per_usec;
static unsigned long next_jiffy_time;
unsigned long iop3xx_gettimeoffset(void)
{
unsigned long offset;
offset = next_jiffy_time - *IOP3XX_TU_TCR1;
return offset / ticks_per_usec;
}
static irqreturn_t
iop3xx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
write_seqlock(&xtime_lock);
iop3xx_cp6_enable();
asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (1));
iop3xx_cp6_disable();
while ((signed long)(next_jiffy_time - *IOP3XX_TU_TCR1)
>= ticks_per_jiffy) {
timer_tick(regs);
next_jiffy_time -= ticks_per_jiffy;
}
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction iop3xx_timer_irq = {
.name = "IOP3XX Timer Tick",
.handler = iop3xx_timer_interrupt,
.flags = IRQF_DISABLED | IRQF_TIMER,
};
void __init iop3xx_init_time(unsigned long tick_rate)
{
u32 timer_ctl;
ticks_per_jiffy = (tick_rate + HZ/2) / HZ;
ticks_per_usec = tick_rate / 1000000;
next_jiffy_time = 0xffffffff;
timer_ctl = IOP3XX_TMR_EN | IOP3XX_TMR_PRIVILEGED |
IOP3XX_TMR_RELOAD | IOP3XX_TMR_RATIO_1_1;
/*
* We use timer 0 for our timer interrupt, and timer 1 as
* monotonic counter for tracking missed jiffies.
*/
iop3xx_cp6_enable();
asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (ticks_per_jiffy - 1));
asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
asm volatile("mcr p6, 0, %0, c5, c1, 0" : : "r" (0xffffffff));
asm volatile("mcr p6, 0, %0, c1, c1, 0" : : "r" (timer_ctl));
iop3xx_cp6_disable();
setup_irq(IRQ_IOP3XX_TIMER0, &iop3xx_timer_irq);
}
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