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MIPS: JZ4740: Add clocksource/clockevent support. 

Add clocksource and clockevent support for the timer/counter unit on
JZ4740 SoCs.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1397/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Lars-Peter Clausen 2010-06-19 04:08:10 +00:00 committed by Ralf Baechle
parent 544a732419
commit b200eff6d1
1 changed files with 144 additions and 0 deletions
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arch/mips/jz4740/time.c Normal file
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/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
* JZ4740 platform time support
*
* 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.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/time.h>
#include <linux/clockchips.h>
#include <asm/mach-jz4740/irq.h>
#include <asm/time.h>
#include "clock.h"
#include "timer.h"
#define TIMER_CLOCKEVENT 0
#define TIMER_CLOCKSOURCE 1
static uint16_t jz4740_jiffies_per_tick;
static cycle_t jz4740_clocksource_read(struct clocksource *cs)
{
return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
}
static struct clocksource jz4740_clocksource = {
.name = "jz4740-timer",
.rating = 200,
.read = jz4740_clocksource_read,
.mask = CLOCKSOURCE_MASK(16),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
{
struct clock_event_device *cd = devid;
jz4740_timer_ack_full(TIMER_CLOCKEVENT);
if (cd->mode != CLOCK_EVT_MODE_PERIODIC)
jz4740_timer_disable(TIMER_CLOCKEVENT);
cd->event_handler(cd);
return IRQ_HANDLED;
}
static void jz4740_clockevent_set_mode(enum clock_event_mode mode,
struct clock_event_device *cd)
{
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
case CLOCK_EVT_MODE_RESUME:
jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
jz4740_timer_enable(TIMER_CLOCKEVENT);
break;
case CLOCK_EVT_MODE_ONESHOT:
case CLOCK_EVT_MODE_SHUTDOWN:
jz4740_timer_disable(TIMER_CLOCKEVENT);
break;
default:
break;
}
}
static int jz4740_clockevent_set_next(unsigned long evt,
struct clock_event_device *cd)
{
jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
jz4740_timer_enable(TIMER_CLOCKEVENT);
return 0;
}
static struct clock_event_device jz4740_clockevent = {
.name = "jz4740-timer",
.features = CLOCK_EVT_FEAT_PERIODIC,
.set_next_event = jz4740_clockevent_set_next,
.set_mode = jz4740_clockevent_set_mode,
.rating = 200,
.irq = JZ4740_IRQ_TCU0,
};
static struct irqaction timer_irqaction = {
.handler = jz4740_clockevent_irq,
.flags = IRQF_PERCPU | IRQF_TIMER,
.name = "jz4740-timerirq",
.dev_id = &jz4740_clockevent,
};
void __init plat_time_init(void)
{
int ret;
uint32_t clk_rate;
uint16_t ctrl;
jz4740_timer_init();
clk_rate = jz4740_clock_bdata.ext_rate >> 4;
jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
clockevent_set_clock(&jz4740_clockevent, clk_rate);
jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
jz4740_clockevent.cpumask = cpumask_of(0);
clockevents_register_device(&jz4740_clockevent);
clocksource_set_clock(&jz4740_clocksource, clk_rate);
ret = clocksource_register(&jz4740_clocksource);
if (ret)
printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
setup_irq(JZ4740_IRQ_TCU0, &timer_irqaction);
ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
jz4740_timer_enable(TIMER_CLOCKEVENT);
jz4740_timer_enable(TIMER_CLOCKSOURCE);
}