175 lines
4.5 KiB
C
175 lines
4.5 KiB
C
/*
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* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
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* JZ4740 platform time support
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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*/
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#include <linux/clk.h>
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#include <linux/clk-provider.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/clockchips.h>
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#include <linux/sched_clock.h>
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#include <asm/mach-jz4740/clock.h>
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#include <asm/mach-jz4740/irq.h>
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#include <asm/mach-jz4740/timer.h>
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#include <asm/time.h>
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#include "clock.h"
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#define TIMER_CLOCKEVENT 0
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#define TIMER_CLOCKSOURCE 1
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static uint16_t jz4740_jiffies_per_tick;
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static cycle_t jz4740_clocksource_read(struct clocksource *cs)
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{
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return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
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}
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static struct clocksource jz4740_clocksource = {
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.name = "jz4740-timer",
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.rating = 200,
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.read = jz4740_clocksource_read,
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.mask = CLOCKSOURCE_MASK(16),
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.flags = CLOCK_SOURCE_IS_CONTINUOUS,
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};
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static u64 notrace jz4740_read_sched_clock(void)
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{
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return jz4740_timer_get_count(TIMER_CLOCKSOURCE);
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}
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static irqreturn_t jz4740_clockevent_irq(int irq, void *devid)
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{
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struct clock_event_device *cd = devid;
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jz4740_timer_ack_full(TIMER_CLOCKEVENT);
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if (!clockevent_state_periodic(cd))
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jz4740_timer_disable(TIMER_CLOCKEVENT);
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cd->event_handler(cd);
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return IRQ_HANDLED;
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}
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static int jz4740_clockevent_set_periodic(struct clock_event_device *evt)
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{
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jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
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jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
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jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
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jz4740_timer_enable(TIMER_CLOCKEVENT);
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return 0;
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}
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static int jz4740_clockevent_resume(struct clock_event_device *evt)
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{
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jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
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jz4740_timer_enable(TIMER_CLOCKEVENT);
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return 0;
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}
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static int jz4740_clockevent_shutdown(struct clock_event_device *evt)
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{
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jz4740_timer_disable(TIMER_CLOCKEVENT);
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return 0;
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}
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static int jz4740_clockevent_set_next(unsigned long evt,
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struct clock_event_device *cd)
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{
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jz4740_timer_set_count(TIMER_CLOCKEVENT, 0);
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jz4740_timer_set_period(TIMER_CLOCKEVENT, evt);
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jz4740_timer_enable(TIMER_CLOCKEVENT);
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return 0;
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}
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static struct clock_event_device jz4740_clockevent = {
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.name = "jz4740-timer",
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.set_next_event = jz4740_clockevent_set_next,
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.set_state_shutdown = jz4740_clockevent_shutdown,
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.set_state_periodic = jz4740_clockevent_set_periodic,
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.set_state_oneshot = jz4740_clockevent_shutdown,
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.tick_resume = jz4740_clockevent_resume,
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.rating = 200,
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#ifdef CONFIG_MACH_JZ4740
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.irq = JZ4740_IRQ_TCU0,
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#endif
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#ifdef CONFIG_MACH_JZ4780
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.irq = JZ4780_IRQ_TCU2,
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#endif
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};
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static struct irqaction timer_irqaction = {
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.handler = jz4740_clockevent_irq,
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.flags = IRQF_PERCPU | IRQF_TIMER,
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.name = "jz4740-timerirq",
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.dev_id = &jz4740_clockevent,
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};
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void __init plat_time_init(void)
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{
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int ret;
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uint32_t clk_rate;
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uint16_t ctrl;
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struct clk *ext_clk;
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of_clk_init(NULL);
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jz4740_timer_init();
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ext_clk = clk_get(NULL, "ext");
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if (IS_ERR(ext_clk))
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panic("unable to get ext clock");
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clk_rate = clk_get_rate(ext_clk) >> 4;
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clk_put(ext_clk);
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jz4740_jiffies_per_tick = DIV_ROUND_CLOSEST(clk_rate, HZ);
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clockevent_set_clock(&jz4740_clockevent, clk_rate);
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jz4740_clockevent.min_delta_ns = clockevent_delta2ns(100, &jz4740_clockevent);
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jz4740_clockevent.max_delta_ns = clockevent_delta2ns(0xffff, &jz4740_clockevent);
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jz4740_clockevent.cpumask = cpumask_of(0);
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clockevents_register_device(&jz4740_clockevent);
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ret = clocksource_register_hz(&jz4740_clocksource, clk_rate);
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if (ret)
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printk(KERN_ERR "Failed to register clocksource: %d\n", ret);
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sched_clock_register(jz4740_read_sched_clock, 16, clk_rate);
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setup_irq(jz4740_clockevent.irq, &timer_irqaction);
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ctrl = JZ_TIMER_CTRL_PRESCALE_16 | JZ_TIMER_CTRL_SRC_EXT;
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jz4740_timer_set_ctrl(TIMER_CLOCKEVENT, ctrl);
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jz4740_timer_set_ctrl(TIMER_CLOCKSOURCE, ctrl);
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jz4740_timer_set_period(TIMER_CLOCKEVENT, jz4740_jiffies_per_tick);
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jz4740_timer_irq_full_enable(TIMER_CLOCKEVENT);
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jz4740_timer_set_period(TIMER_CLOCKSOURCE, 0xffff);
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jz4740_timer_enable(TIMER_CLOCKEVENT);
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jz4740_timer_enable(TIMER_CLOCKSOURCE);
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}
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