cevt-gt641xx.c

Go to the documentation of this file.

/*
 *  GT641xx clockevent routines.
 *
 *  Copyright (C) 2007  Yoichi Yuasa <[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, write to the Free Software
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
#include <linux/clockchips.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/irq.h>

#include <asm/gt64120.h>
#include <asm/time.h>

static DEFINE_RAW_SPINLOCK(gt641xx_timer_lock);
static unsigned int gt641xx_base_clock;

void gt641xx_set_base_clock(unsigned int clock)
{
    gt641xx_base_clock = clock;
}

int gt641xx_timer0_state(void)
{
    if (GT_READ(GT_TC0_OFS))
        return 0;

    GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);
    GT_WRITE(GT_TC_CONTROL_OFS, GT_TC_CONTROL_ENTC0_MSK);

    return 1;
}

static int gt641xx_timer0_set_next_event(unsigned long delta,
                     struct clock_event_device *evt)
{
    u32 ctrl;

    raw_spin_lock(&gt641xx_timer_lock);

    ctrl = GT_READ(GT_TC_CONTROL_OFS);
    ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);
    ctrl |= GT_TC_CONTROL_ENTC0_MSK;

    GT_WRITE(GT_TC0_OFS, delta);
    GT_WRITE(GT_TC_CONTROL_OFS, ctrl);

    raw_spin_unlock(&gt641xx_timer_lock);

    return 0;
}

static void gt641xx_timer0_set_mode(enum clock_event_mode mode,
                    struct clock_event_device *evt)
{
    u32 ctrl;

    raw_spin_lock(&gt641xx_timer_lock);

    ctrl = GT_READ(GT_TC_CONTROL_OFS);
    ctrl &= ~(GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK);

    switch (mode) {
    case CLOCK_EVT_MODE_PERIODIC:
        ctrl |= GT_TC_CONTROL_ENTC0_MSK | GT_TC_CONTROL_SELTC0_MSK;
        break;
    case CLOCK_EVT_MODE_ONESHOT:
        ctrl |= GT_TC_CONTROL_ENTC0_MSK;
        break;
    default:
        break;
    }

    GT_WRITE(GT_TC_CONTROL_OFS, ctrl);

    raw_spin_unlock(&gt641xx_timer_lock);
}

static void gt641xx_timer0_event_handler(struct clock_event_device *dev)
{
}

static struct clock_event_device gt641xx_timer0_clockevent = {
    .name       = "gt641xx-timer0",
    .features   = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
    .irq        = GT641XX_TIMER0_IRQ,
    .set_next_event = gt641xx_timer0_set_next_event,
    .set_mode   = gt641xx_timer0_set_mode,
    .event_handler  = gt641xx_timer0_event_handler,
};

static irqreturn_t gt641xx_timer0_interrupt(int irq, void *dev_id)
{
    struct clock_event_device *cd = &gt641xx_timer0_clockevent;

    cd->event_handler(cd);

    return IRQ_HANDLED;
}

static struct irqaction gt641xx_timer0_irqaction = {
    .handler    = gt641xx_timer0_interrupt,
    .flags      = IRQF_PERCPU | IRQF_TIMER,
    .name       = "gt641xx_timer0",
};

static int __init gt641xx_timer0_clockevent_init(void)
{
    struct clock_event_device *cd;

    if (!gt641xx_base_clock)
        return 0;

    GT_WRITE(GT_TC0_OFS, gt641xx_base_clock / HZ);

    cd = &gt641xx_timer0_clockevent;
    cd->rating = 200 + gt641xx_base_clock / 10000000;
    clockevent_set_clock(cd, gt641xx_base_clock);
    cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
    cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
    cd->cpumask = cpumask_of(0);

    clockevents_register_device(&gt641xx_timer0_clockevent);

    return setup_irq(GT641XX_TIMER0_IRQ, &gt641xx_timer0_irqaction);
}
arch_initcall(gt641xx_timer0_clockevent_init);