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/*
* arch/arm/mach-iop33x/time.c
*
* Timer code for IOP331 based systems
*
* Author: Dave Jiang <dave.jiang@intel.com>
*
* Copyright 2003 Intel Corp.
*
* 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>
static inline unsigned long get_elapsed(void)
{
return LATCH - *IOP331_TU_TCR0;
}
static unsigned long iop331_gettimeoffset(void)
{
unsigned long elapsed, usec;
u32 tisr1, tisr2;
/*
* If an interrupt was pending before we read the timer,
* we've already wrapped. Factor this into the time.
* If an interrupt was pending after we read the timer,
* it may have wrapped between checking the interrupt
* status and reading the timer. Re-read the timer to
* be sure its value is after the wrap.
*/
asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr1));
elapsed = get_elapsed();
asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr2));
if(tisr1 & 1)
elapsed += LATCH;
else if (tisr2 & 1)
elapsed = LATCH + get_elapsed();
/*
* Now convert them to usec.
*/
usec = (unsigned long)(elapsed / (CLOCK_TICK_RATE/1000000));
return usec;
}
static irqreturn_t
iop331_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
u32 tisr;
write_seqlock(&xtime_lock);
asm volatile("mrc p6, 0, %0, c6, c1, 0" : "=r" (tisr));
tisr |= 1;
asm volatile("mcr p6, 0, %0, c6, c1, 0" : : "r" (tisr));
timer_tick(regs);
write_sequnlock(&xtime_lock);
return IRQ_HANDLED;
}
static struct irqaction iop331_timer_irq = {
.name = "IOP331 Timer Tick",
.handler = iop331_timer_interrupt,
.flags = IRQF_DISABLED | IRQF_TIMER,
};
static void __init iop331_timer_init(void)
{
u32 timer_ctl;
setup_irq(IRQ_IOP331_TIMER0, &iop331_timer_irq);
timer_ctl = IOP331_TMR_EN | IOP331_TMR_PRIVILEGED | IOP331_TMR_RELOAD |
IOP331_TMR_RATIO_1_1;
asm volatile("mcr p6, 0, %0, c4, c1, 0" : : "r" (LATCH));
asm volatile("mcr p6, 0, %0, c0, c1, 0" : : "r" (timer_ctl));
}
struct sys_timer iop331_timer = {
.init = iop331_timer_init,
.offset = iop331_gettimeoffset,
};
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