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+/*
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+ * linux/arch/arm/plat-mxc/time.c
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+ *
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+ * Copyright (C) 2000-2001 Deep Blue Solutions
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+ * Copyright (C) 2002 Shane Nay (shane@minirl.com)
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+ * Copyright (C) 2006-2007 Pavel Pisa (ppisa@pikron.com)
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+ * Copyright (C) 2008 Juergen Beisert (kernel@pengutronix.de)
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+ *
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+ * This program is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU General Public License
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+ * as published by the Free Software Foundation; either version 2
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+ * of the License, or (at your option) any later version.
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+ * This program is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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+ * GNU General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU General Public License
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+ * along with this program; if not, write to the Free Software
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+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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+ * MA 02110-1301, USA.
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+ */
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+
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+#include <linux/interrupt.h>
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+#include <linux/irq.h>
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+#include <linux/clockchips.h>
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+#include <linux/clk.h>
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+
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+#include <asm/hardware.h>
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+#include <asm/mach/time.h>
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+#include <asm/arch/common.h>
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+#include <asm/arch/mxc_timer.h>
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+
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+static struct clock_event_device clockevent_mxc;
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+static enum clock_event_mode clockevent_mode = CLOCK_EVT_MODE_UNUSED;
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+
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+/* clock source for the timer */
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+static struct clk *timer_clk;
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+
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+/* clock source */
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+
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+static cycle_t mxc_get_cycles(void)
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+{
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+ return __raw_readl(TIMER_BASE + MXC_TCN);
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+}
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+
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+static struct clocksource clocksource_mxc = {
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+ .name = "mxc_timer1",
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+ .rating = 200,
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+ .read = mxc_get_cycles,
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+ .mask = CLOCKSOURCE_MASK(32),
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+ .shift = 20,
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+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
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+};
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+
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+static int __init mxc_clocksource_init(void)
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+{
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+ unsigned int clock;
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+
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+ clock = clk_get_rate(timer_clk);
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+
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+ clocksource_mxc.mult = clocksource_hz2mult(clock,
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+ clocksource_mxc.shift);
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+ clocksource_register(&clocksource_mxc);
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+
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+ return 0;
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+}
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+
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+/* clock event */
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+
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+static int mxc_set_next_event(unsigned long evt,
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+ struct clock_event_device *unused)
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+{
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+ unsigned long tcmp;
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+
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+ tcmp = __raw_readl(TIMER_BASE + MXC_TCN) + evt;
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+ __raw_writel(tcmp, TIMER_BASE + MXC_TCMP);
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+
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+ return (int)(tcmp - __raw_readl(TIMER_BASE + MXC_TCN)) < 0 ?
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+ -ETIME : 0;
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+}
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+
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+#ifdef DEBUG
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+static const char *clock_event_mode_label[] = {
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+ [CLOCK_EVT_MODE_PERIODIC] = "CLOCK_EVT_MODE_PERIODIC",
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+ [CLOCK_EVT_MODE_ONESHOT] = "CLOCK_EVT_MODE_ONESHOT",
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+ [CLOCK_EVT_MODE_SHUTDOWN] = "CLOCK_EVT_MODE_SHUTDOWN",
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+ [CLOCK_EVT_MODE_UNUSED] = "CLOCK_EVT_MODE_UNUSED"
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+};
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+#endif /* DEBUG */
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+
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+static void mxc_set_mode(enum clock_event_mode mode,
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+ struct clock_event_device *evt)
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+{
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+ unsigned long flags;
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+
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+ /*
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+ * The timer interrupt generation is disabled at least
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+ * for enough time to call mxc_set_next_event()
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+ */
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+ local_irq_save(flags);
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+
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+ /* Disable interrupt in GPT module */
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+ gpt_irq_disable();
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+
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+ if (mode != clockevent_mode) {
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+ /* Set event time into far-far future */
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+ __raw_writel(__raw_readl(TIMER_BASE + MXC_TCN) - 3,
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+ TIMER_BASE + MXC_TCMP);
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+ /* Clear pending interrupt */
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+ gpt_irq_acknowledge();
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+ }
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+
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+#ifdef DEBUG
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+ printk(KERN_INFO "mxc_set_mode: changing mode from %s to %s\n",
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+ clock_event_mode_label[clockevent_mode],
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+ clock_event_mode_label[mode]);
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+#endif /* DEBUG */
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+
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+ /* Remember timer mode */
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+ clockevent_mode = mode;
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+ local_irq_restore(flags);
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+
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+ switch (mode) {
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+ case CLOCK_EVT_MODE_PERIODIC:
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+ printk(KERN_ERR"mxc_set_mode: Periodic mode is not "
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+ "supported for i.MX\n");
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+ break;
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+ case CLOCK_EVT_MODE_ONESHOT:
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+ /*
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+ * Do not put overhead of interrupt enable/disable into
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+ * mxc_set_next_event(), the core has about 4 minutes
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+ * to call mxc_set_next_event() or shutdown clock after
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+ * mode switching
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+ */
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+ local_irq_save(flags);
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+ gpt_irq_enable();
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+ local_irq_restore(flags);
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+ break;
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+ case CLOCK_EVT_MODE_SHUTDOWN:
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+ case CLOCK_EVT_MODE_UNUSED:
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+ case CLOCK_EVT_MODE_RESUME:
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+ /* Left event sources disabled, no more interrupts appear */
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+ break;
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+ }
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+}
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+
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+/*
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+ * IRQ handler for the timer
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+ */
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+static irqreturn_t mxc_timer_interrupt(int irq, void *dev_id)
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+{
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+ struct clock_event_device *evt = &clockevent_mxc;
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+ uint32_t tstat;
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+
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+ tstat = __raw_readl(TIMER_BASE + MXC_TSTAT);
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+
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+ gpt_irq_acknowledge();
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+
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+ evt->event_handler(evt);
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+
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+ return IRQ_HANDLED;
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+}
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+
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+static struct irqaction mxc_timer_irq = {
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+ .name = "i.MX Timer Tick",
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+ .flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
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+ .handler = mxc_timer_interrupt,
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+};
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+
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+static struct clock_event_device clockevent_mxc = {
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+ .name = "mxc_timer1",
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+ .features = CLOCK_EVT_FEAT_ONESHOT,
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+ .shift = 32,
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+ .set_mode = mxc_set_mode,
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+ .set_next_event = mxc_set_next_event,
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+ .rating = 200,
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+};
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+
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+static int __init mxc_clockevent_init(void)
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+{
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+ unsigned int clock;
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+
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+ clock = clk_get_rate(timer_clk);
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+
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+ clockevent_mxc.mult = div_sc(clock, NSEC_PER_SEC,
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+ clockevent_mxc.shift);
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+ clockevent_mxc.max_delta_ns =
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+ clockevent_delta2ns(0xfffffffe, &clockevent_mxc);
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+ clockevent_mxc.min_delta_ns =
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+ clockevent_delta2ns(0xff, &clockevent_mxc);
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+
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+ clockevent_mxc.cpumask = cpumask_of_cpu(0);
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+
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+ clockevents_register_device(&clockevent_mxc);
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+
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+ return 0;
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+}
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+
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+void __init mxc_timer_init(const char *clk_timer)
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+{
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+ timer_clk = clk_get(NULL, clk_timer);
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+ if (!timer_clk) {
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+ printk(KERN_ERR"Cannot determine timer clock. Giving up.\n");
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+ return;
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+ }
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+
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+ clk_enable(timer_clk);
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+
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+ /*
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+ * Initialise to a known state (all timers off, and timing reset)
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+ */
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+ __raw_writel(0, TIMER_BASE + MXC_TCTL);
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+ __raw_writel(0, TIMER_BASE + MXC_TPRER); /* see datasheet note */
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+
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+ __raw_writel(TCTL_FRR | /* free running */
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+ TCTL_VAL | /* set clocksource and arch specific bits */
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+ TCTL_TEN, /* start the timer */
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+ TIMER_BASE + MXC_TCTL);
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+
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+ /* init and register the timer to the framework */
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+ mxc_clocksource_init();
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+ mxc_clockevent_init();
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+
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+ /* Make irqs happen */
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+ setup_irq(TIMER_INTERRUPT, &mxc_timer_irq);
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+}
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+
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