89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
|
/*
|
||
|
|
* arch/arm/mach-ns9xxx/time.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 2006 by Digi International Inc.
|
||
|
|
* All rights reserved.
|
||
|
|
*
|
||
|
|
* This program is free software; you can redistribute it and/or modify it
|
||
|
|
* under the terms of the GNU General Public License version 2 as published by
|
||
|
|
* the Free Software Foundation.
|
||
|
|
*/
|
||
|
|
#include <linux/jiffies.h>
|
||
|
|
#include <linux/interrupt.h>
|
||
|
|
#include <linux/irq.h>
|
||
|
|
#include <asm/arch-ns9xxx/regs-sys.h>
|
||
|
|
#include <asm/arch-ns9xxx/clock.h>
|
||
|
|
#include <asm/arch-ns9xxx/irqs.h>
|
||
|
|
#include <asm/arch/system.h>
|
||
|
|
#include "generic.h"
|
||
|
|
|
||
|
|
#define TIMERCLOCKSELECT 64
|
||
|
|
|
||
|
|
static u32 usecs_per_tick;
|
||
|
|
|
||
|
|
static irqreturn_t
|
||
|
|
ns9xxx_timer_interrupt(int irq, void *dev_id)
|
||
|
|
{
|
||
|
|
write_seqlock(&xtime_lock);
|
||
|
|
timer_tick();
|
||
|
|
write_sequnlock(&xtime_lock);
|
||
|
|
|
||
|
|
return IRQ_HANDLED;
|
||
|
|
}
|
||
|
|
|
||
|
|
static unsigned long ns9xxx_timer_gettimeoffset(void)
|
||
|
|
{
|
||
|
|
/* return the microseconds which have passed since the last interrupt
|
||
|
|
* was _serviced_. That is, if an interrupt is pending or the counter
|
||
|
|
* reloads, return one periode more. */
|
||
|
|
|
||
|
|
u32 counter1 = SYS_TR(0);
|
||
|
|
int pending = SYS_ISR & (1 << IRQ_TIMER0);
|
||
|
|
u32 counter2 = SYS_TR(0);
|
||
|
|
u32 elapsed;
|
||
|
|
|
||
|
|
if (pending || counter2 > counter1)
|
||
|
|
elapsed = 2 * SYS_TRC(0) - counter2;
|
||
|
|
else
|
||
|
|
elapsed = SYS_TRC(0) - counter1;
|
||
|
|
|
||
|
|
return (elapsed * usecs_per_tick) >> 16;
|
||
|
|
|
||
|
|
}
|
||
|
|
|
||
|
|
static struct irqaction ns9xxx_timer_irq = {
|
||
|
|
.name = "NS9xxx Timer Tick",
|
||
|
|
.flags = IRQF_DISABLED | IRQF_TIMER,
|
||
|
|
.handler = ns9xxx_timer_interrupt,
|
||
|
|
};
|
||
|
|
|
||
|
|
static void __init ns9xxx_timer_init(void)
|
||
|
|
{
|
||
|
|
int tc;
|
||
|
|
|
||
|
|
usecs_per_tick =
|
||
|
|
SH_DIV(1000000 * TIMERCLOCKSELECT, ns9xxx_cpuclock(), 16);
|
||
|
|
|
||
|
|
/* disable timer */
|
||
|
|
if ((tc = SYS_TC(0)) & SYS_TCx_TEN)
|
||
|
|
SYS_TC(0) = tc & ~SYS_TCx_TEN;
|
||
|
|
|
||
|
|
SYS_TRC(0) = SH_DIV(ns9xxx_cpuclock(), (TIMERCLOCKSELECT * HZ), 0);
|
||
|
|
|
||
|
|
REGSET(tc, SYS_TCx, TEN, EN);
|
||
|
|
REGSET(tc, SYS_TCx, TLCS, DIV64); /* This must match TIMERCLOCKSELECT */
|
||
|
|
REGSET(tc, SYS_TCx, INTS, EN);
|
||
|
|
REGSET(tc, SYS_TCx, UDS, DOWN);
|
||
|
|
REGSET(tc, SYS_TCx, TDBG, STOP);
|
||
|
|
REGSET(tc, SYS_TCx, TSZ, 32);
|
||
|
|
REGSET(tc, SYS_TCx, REN, EN);
|
||
|
|
SYS_TC(0) = tc;
|
||
|
|
|
||
|
|
setup_irq(IRQ_TIMER0, &ns9xxx_timer_irq);
|
||
|
|
}
|
||
|
|
|
||
|
|
struct sys_timer ns9xxx_timer = {
|
||
|
|
.init = ns9xxx_timer_init,
|
||
|
|
.offset = ns9xxx_timer_gettimeoffset,
|
||
|
|
};
|