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/*
* System timer for Freescale i.MXS
*
* Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved.
* Copyright (C) 2009-2010 Freescale Semiconductor, 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/clocksource.h>
#include <linux/clockchips.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <asm/mach/time.h>
#include <mach/device.h>
#include <mach/regs-timrot.h>
static struct mxs_sys_timer *online_timer;
static irqreturn_t mxs_timer_handler(int irq, void *dev_id);
static cycle_t mxs_get_cycles(struct clocksource *cs)
{
return ~__raw_readl(online_timer->base +
HW_TIMROT_RUNNING_COUNTn(online_timer->id));
}
static int mxs_set_next_event(unsigned long delta,
struct clock_event_device *dev)
{
unsigned int match;
match = __raw_readl(online_timer->base +
HW_TIMROT_RUNNING_COUNTn(online_timer->id)) - delta;
__raw_writel(match, online_timer->base +
HW_TIMROT_MATCH_COUNTn(online_timer->id));
return (int)(match -
__raw_readl(online_timer->base +
HW_TIMROT_RUNNING_COUNTn(online_timer->id)))
> 0 ? -ETIME : 0;
}
static void mxs_set_mode(enum clock_event_mode mode,
struct clock_event_device *evt)
{
switch (mode) {
case CLOCK_EVT_MODE_SHUTDOWN:
__raw_writel(BM_TIMROT_TIMCTRLn_IRQ_EN | BM_TIMROT_TIMCTRLn_IRQ,
online_timer->base + HW_TIMROT_TIMCTRLn_CLR(0));
break;
case CLOCK_EVT_MODE_RESUME:
case CLOCK_EVT_MODE_ONESHOT:
__raw_writel(BM_TIMROT_ROTCTRL_SFTRST | BM_TIMROT_ROTCTRL_CLKGATE,
online_timer->base + HW_TIMROT_ROTCTRL_CLR);
__raw_writel(BF_TIMROT_TIMCTRLn_SELECT(online_timer->clk_sel) |
BM_TIMROT_TIMCTRLn_IRQ_EN |
BM_TIMROT_TIMCTRLn_MATCH_MODE,
online_timer->base + HW_TIMROT_TIMCTRLn(online_timer->id));
break;
default:
break;
}
}
static struct clock_event_device mxs_clockevent = {
.name = "mxs tick timer ",
.features = CLOCK_EVT_FEAT_ONESHOT,
.shift = 32,
.set_next_event = mxs_set_next_event,
.set_mode = mxs_set_mode,
.rating = 200,
};
static struct clocksource mxs_clocksource = {
.name = "mxs clock source",
.rating = 250,
.read = mxs_get_cycles,
.mask = CLOCKSOURCE_MASK(32),
.shift = 10,
.flags = CLOCK_SOURCE_IS_CONTINUOUS
};
static struct irqaction mxs_timer_irq = {
.name = "i.MX/mxs Timer Tick",
.flags = IRQF_DISABLED | IRQF_TIMER,
.handler = mxs_timer_handler,
.dev_id = &mxs_clockevent,
};
static int __init mxs_clocksource_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
mxs_clocksource.mult = clocksource_hz2mult(c, mxs_clocksource.shift);
clocksource_register(&mxs_clocksource);
return 0;
}
static int __init mxs_clockevent_init(struct clk *timer_clk)
{
unsigned int c = clk_get_rate(timer_clk);
mxs_clockevent.mult = div_sc(c, NSEC_PER_SEC, mxs_clockevent.shift);
mxs_clockevent.min_delta_ns = clockevent_delta2ns(0xF, &mxs_clockevent);
mxs_clockevent.max_delta_ns = clockevent_delta2ns(0xFFFFFFF0,
&mxs_clockevent);
mxs_clockevent.cpumask = cpumask_of(0);
clockevents_register_device(&mxs_clockevent);
return 0;
}
static irqreturn_t mxs_timer_handler(int irq, void *dev_id)
{
struct clock_event_device *c = dev_id;
if (__raw_readl(online_timer->base +
HW_TIMROT_TIMCTRLn(online_timer->id)) &
BM_TIMROT_TIMCTRLn_IRQ) {
__raw_writel(BM_TIMROT_TIMCTRLn_IRQ,
online_timer->base +
HW_TIMROT_TIMCTRLn_CLR(online_timer->id));
c->event_handler(c);
}
return IRQ_HANDLED;
}
void mxs_timer_init(struct mxs_sys_timer *timer)
{
if (!timer->base || !timer->clk || IS_ERR(timer->clk))
return;
if (online_timer)
return;
online_timer = timer;
clk_enable(online_timer->clk);
__raw_writel(BF_TIMROT_TIMCTRLn_SELECT(online_timer->clk_sel) |
BM_TIMROT_TIMCTRLn_IRQ_EN |
BM_TIMROT_TIMCTRLn_MATCH_MODE,
online_timer->base + HW_TIMROT_TIMCTRLn(online_timer->id));
mxs_clocksource_init(online_timer->clk);
mxs_clockevent_init(online_timer->clk);
setup_irq(online_timer->irq, &mxs_timer_irq);
}
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