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/*
* linux/arch/arm/mach-mmp/time.c
*
* Support for clocksource and clockevents
*
* Copyright (C) 2008 Marvell International Ltd.
* All rights reserved.
*
* 2008-04-11: Jason Chagas <Jason.chagas@marvell.com>
* 2008-10-08: Bin Yang <bin.yang@marvell.com>
*
* The timers module actually includes three timers, each timer with upto
* three match comparators. Timer #0 is used here in free-running mode as
* the clock source, and match comparator #1 used as clock event device.
*
* 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/init.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/sched.h>
#include <linux/cnt32_to_63.h>
#include <mach/addr-map.h>
#include <mach/regs-timers.h>
#include <mach/irqs.h>
#include "clock.h"
#define TIMERS_VIRT_BASE TIMERS1_VIRT_BASE
#define MAX_DELTA (0xfffffffe)
#define MIN_DELTA (16)
#define TCR2NS_SCALE_FACTOR 10
static unsigned long tcr2ns_scale;
static void __init set_tcr2ns_scale(unsigned long tcr_rate)
{
unsigned long long v = 1000000000ULL << TCR2NS_SCALE_FACTOR;
do_div(v, tcr_rate);
tcr2ns_scale = v;
/*
* We want an even value to automatically clear the top bit
* returned by cnt32_to_63() without an additional run time
* instruction. So if the LSB is 1 then round it up.
*/
if (tcr2ns_scale & 1)
tcr2ns_scale++;
}
/*
* FIXME: the timer needs some delay to stablize the counter capture
*/
static inline uint32_t timer_read(void)
{
int delay = 100;
__raw_writel(1, TIMERS_VIRT_BASE + TMR_CVWR(0));
while (delay--)
cpu_relax();
return __raw_readl(TIMERS_VIRT_BASE + TMR_CVWR(0));
}
unsigned long long sched_clock(void)
{
unsigned long long v = cnt32_to_63(timer_read());
return (v * tcr2ns_scale) >> TCR2NS_SCALE_FACTOR;
}
static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
/* disable and clear pending interrupt status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
__raw_writel(0x1, TIMERS_VIRT_BASE + TMR_ICR(0));
c->event_handler(c);
return IRQ_HANDLED;
}
static int timer_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
unsigned long flags, next;
local_irq_save(flags);
/* clear pending interrupt status and enable */
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_ICR(0));
__raw_writel(0x01, TIMERS_VIRT_BASE + TMR_IER(0));
next = timer_read() + delta;
__raw_writel(next, TIMERS_VIRT_BASE + TMR_TN_MM(0, 0));
local_irq_restore(flags);
return 0;
}
static void timer_set_mode(enum clock_event_mode mode,
struct clock_event_device *dev)
{
unsigned long flags;
local_irq_save(flags);
switch (mode) {
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_UNUSED:
case CLOCK_EVT_MODE_SHUTDOWN:
/* disable the matching interrupt */
__raw_writel(0x00, TIMERS_VIRT_BASE + TMR_IER(0));
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_PERIODIC:
break;
}
local_irq_restore(flags);
}
static struct clock_event_device ckevt = {
.name = "clockevent",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.rating = 200,
.set_next_event = timer_set_next_event,
.set_mode = timer_set_mode,
};
static cycle_t clksrc_read(struct clocksource *cs)
{
return timer_read();
}
static struct clocksource cksrc = {
.name = "clocksource",
.shift = 20,
.rating = 200,
.read = clksrc_read,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init timer_config(void)
{
uint32_t ccr = __raw_readl(TIMERS_VIRT_BASE + TMR_CCR);
uint32_t cer = __raw_readl(TIMERS_VIRT_BASE + TMR_CER);
uint32_t cmr = __raw_readl(TIMERS_VIRT_BASE + TMR_CMR);
__raw_writel(cer & ~0x1, TIMERS_VIRT_BASE + TMR_CER); /* disable */
ccr &= TMR_CCR_CS_0(0x3);
__raw_writel(ccr, TIMERS_VIRT_BASE + TMR_CCR);
/* free-running mode */
__raw_writel(cmr | 0x01, TIMERS_VIRT_BASE + TMR_CMR);
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_PLCR(0)); /* free-running */
__raw_writel(0x7, TIMERS_VIRT_BASE + TMR_ICR(0)); /* clear status */
__raw_writel(0x0, TIMERS_VIRT_BASE + TMR_IER(0));
/* enable timer counter */
__raw_writel(cer | 0x01, TIMERS_VIRT_BASE + TMR_CER);
}
static struct irqaction timer_irq = {
.name = "timer",
.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = timer_interrupt,
.dev_id = &ckevt,
};
void __init timer_init(int irq)
{
timer_config();
set_tcr2ns_scale(CLOCK_TICK_RATE);
ckevt.mult = div_sc(CLOCK_TICK_RATE, NSEC_PER_SEC, ckevt.shift);
ckevt.max_delta_ns = clockevent_delta2ns(MAX_DELTA, &ckevt);
ckevt.min_delta_ns = clockevent_delta2ns(MIN_DELTA, &ckevt);
ckevt.cpumask = cpumask_of(0);
cksrc.mult = clocksource_hz2mult(CLOCK_TICK_RATE, cksrc.shift);
setup_irq(irq, &timer_irq);
clocksource_register(&cksrc);
clockevents_register_device(&ckevt);
}
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