linux-imx

#define MTU_PCELL2  0xff8

#define MTU_PCELL3  0xffC

​

static void __iomem *mtu_base;

static bool clkevt_periodic;

static u32 clk_prescale;

static u32 nmdk_cycle;      /* write-once */

static struct delay_timer mtu_delay_timer;

​

/*

 * Override the global weak sched_clock symbol with this

 * local implementation which uses the clocksource to get some

 * better resolution when scheduling the kernel.

 */

static u64 notrace nomadik_read_sched_clock(void)

{

    if (unlikely(!mtu_base))

        return 0;

​

    return -readl(mtu_base + MTU_VAL(0));

}

​

static unsigned long nmdk_timer_read_current_timer(void)

{

    return ~readl_relaxed(mtu_base + MTU_VAL(0));

}

​

/* Clockevent device: use one-shot mode */

static int nmdk_clkevt_next(unsigned long evt, struct clock_event_device *ev)

{

    writel(1 << 1, mtu_base + MTU_IMSC);

    nmdk_clksrc_reset();

​

    ret = clocksource_mmio_init(mtu_base + MTU_VAL(0), "mtu_0",

                    rate, 200, 32, clocksource_mmio_readl_down);

    if (ret) {

        pr_err("timer: failed to initialize clock source %s\n", "mtu_0");

        return ret;

    }

​

    sched_clock_register(nomadik_read_sched_clock, 32, rate);

​

    /* Timer 1 is used for events, register irq and clockevents */

    setup_irq(irq, &nmdk_timer_irq);

    nmdk_clkevt.cpumask = cpumask_of(0);

    nmdk_clkevt.irq = irq;

    clockevents_config_and_register(&nmdk_clkevt, rate, 2, 0xffffffffU);

​

    mtu_delay_timer.read_current_timer = &nmdk_timer_read_current_timer;

    mtu_delay_timer.freq = rate;

    register_current_timer_delay(&mtu_delay_timer);