time.c

Go to the documentation of this file.

/*
 * arch/score/kernel/time.c
 *
 * Score Processor version.
 *
 * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
 *  Chen Liqin <[email protected]>
 *  Lennox Wu <[email protected]>
 *
 * 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, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include <linux/clockchips.h>
#include <linux/interrupt.h>

#include <asm/scoreregs.h>

static irqreturn_t timer_interrupt(int irq, void *dev_id)
{
    struct clock_event_device *evdev = dev_id;

    /* clear timer interrupt flag */
    outl(1, P_TIMER0_CPP_REG);
    evdev->event_handler(evdev);

    return IRQ_HANDLED;
}

static struct irqaction timer_irq = {
    .handler = timer_interrupt,
    .flags = IRQF_DISABLED | IRQF_TIMER,
    .name = "timer",
};

static int score_timer_set_next_event(unsigned long delta,
        struct clock_event_device *evdev)
{
    outl((TMR_M_PERIODIC | TMR_IE_ENABLE), P_TIMER0_CTRL);
    outl(delta, P_TIMER0_PRELOAD);
    outl(inl(P_TIMER0_CTRL) | TMR_ENABLE, P_TIMER0_CTRL);

    return 0;
}

static void score_timer_set_mode(enum clock_event_mode mode,
        struct clock_event_device *evdev)
{
    switch (mode) {
    case CLOCK_EVT_MODE_PERIODIC:
        outl((TMR_M_PERIODIC | TMR_IE_ENABLE), P_TIMER0_CTRL);
        outl(SYSTEM_CLOCK/HZ, P_TIMER0_PRELOAD);
        outl(inl(P_TIMER0_CTRL) | TMR_ENABLE, P_TIMER0_CTRL);
        break;
    case CLOCK_EVT_MODE_ONESHOT:
    case CLOCK_EVT_MODE_SHUTDOWN:
    case CLOCK_EVT_MODE_RESUME:
    case CLOCK_EVT_MODE_UNUSED:
        break;
    default:
        BUG();
    }
}

static struct clock_event_device score_clockevent = {
    .name       = "score_clockevent",
    .features   = CLOCK_EVT_FEAT_PERIODIC,
    .shift      = 16,
    .set_next_event = score_timer_set_next_event,
    .set_mode   = score_timer_set_mode,
};

void __init time_init(void)
{
    timer_irq.dev_id = &score_clockevent;
    setup_irq(IRQ_TIMER , &timer_irq);

    /* setup COMPARE clockevent */
    score_clockevent.mult = div_sc(SYSTEM_CLOCK, NSEC_PER_SEC,
                    score_clockevent.shift);
    score_clockevent.max_delta_ns = clockevent_delta2ns((u32)~0,
                    &score_clockevent);
    score_clockevent.min_delta_ns = clockevent_delta2ns(50,
                        &score_clockevent) + 1;
    score_clockevent.cpumask = cpumask_of(0);
    clockevents_register_device(&score_clockevent);
}