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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>
#include <asm/arch/time.h>
static unsigned long ticks_per_jiffy;
static unsigned long ticks_per_usec;
static unsigned long next_jiffy_time;
unsigned long iop_gettimeoffset(void)
{
unsigned long offset, temp;
/* enable cp6, if necessary, to avoid taking the overhead of an
* undefined instruction trap
*/
asm volatile (
"mrc p15, 0, %0, c15, c1, 0\n\t"
"tst %0, #(1 << 6)\n\t"
"orreq %0, %0, #(1 << 6)\n\t"
"mcreq p15, 0, %0, c15, c1, 0\n\t"
#ifdef CONFIG_CPU_XSCALE
"mrceq p15, 0, %0, c15, c1, 0\n\t"
"moveq %0, %0\n\t"
"subeq pc, pc, #4\n\t"
#endif
: "=r"(temp) : : "cc");
offset = next_jiffy_time - read_tcr1();
return offset / ticks_per_usec;
}
static irqreturn_t
iop_timer_interrupt(int irq, void *dev_id)
{
write_seqlock(&xtime_lock);
write_tisr(1);
while ((signed long)(next_jiffy_time - read_tcr1())
>= ticks_per_jiffy) {
timer_tick();
next_jiffy_time -= ticks_per_jiffy;
}
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction iop_timer_irq = {
.name = "IOP Timer Tick",
.handler = iop_timer_interrupt,
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
};
void __init iop_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 = IOP_TMR_EN | IOP_TMR_PRIVILEGED |
IOP_TMR_RELOAD | IOP_TMR_RATIO_1_1;
/*
* We use timer 0 for our timer interrupt, and timer 1 as
* monotonic counter for tracking missed jiffies.
*/
write_trr0(ticks_per_jiffy - 1);
write_tmr0(timer_ctl);
write_trr1(0xffffffff);
write_tmr1(timer_ctl);
setup_irq(IRQ_IOP_TIMER0, &iop_timer_irq);
}
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