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    Subject[RFC][PATCH 05/26] MIPS: JZ4740: Add clocksource/clockevent support.
    Date
    This patch add clocksource and clockevent support for the timer/counter unit on
    JZ4740 SoCs.

    Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    ---
    arch/mips/jz4740/time.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++
    1 files changed, 144 insertions(+), 0 deletions(-)
    create mode 100644 arch/mips/jz4740/time.c

    diff --git a/arch/mips/jz4740/time.c b/arch/mips/jz4740/time.c
    new file mode 100644
    index 0000000..da8183f
    --- /dev/null
    +++ b/arch/mips/jz4740/time.c
    @@ -0,0 +1,144 @@
    +/*
    + * 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 | IRQF_DISABLED,
    + .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);
    +}
    --
    1.5.6.5


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