Commit 3efe7a87 authored by Tony Lindgren's avatar Tony Lindgren Committed by Daniel Lezcano
Browse files

clocksource/drivers/timer-ti-dm: Prepare to handle dra7 timer wrap issue 



There is a timer wrap issue on dra7 for the ARM architected timer.
In a typical clock configuration the timer fails to wrap after 388 days.

To work around the issue, we need to use timer-ti-dm timers instead.

Let's prepare for adding support for percpu timers by adding a common
dmtimer_clkevt_init_common() and call it from dmtimer_clockevent_init().
This patch makes no intentional functional changes.

Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210323074326.28302-2-tony@atomide.com
parent 397dc6f7

drivers/clocksource/timer-ti-dm-systimer.c

+43 −23
Original line number Diff line number Diff line
@@ -530,17 +530,17 @@ static void omap_clockevent_unidle(struct clock_event_device *evt) 
	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);

}



static int __init dmtimer_clockevent_init(struct device_node *np)

static int __init dmtimer_clkevt_init_common(struct dmtimer_clockevent *clkevt,

					     struct device_node *np,

					     unsigned int features,

					     const struct cpumask *cpumask,

					     const char *name,

					     int rating)

{

	struct dmtimer_clockevent *clkevt;

	struct clock_event_device *dev;

	struct dmtimer_systimer *t;

	int error;



	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);

	if (!clkevt)

		return -ENOMEM;



	t = &clkevt->t;

	dev = &clkevt->dev;
@@ -548,25 +548,23 @@ static int __init dmtimer_clockevent_init(struct device_node *np) 
	 * We mostly use cpuidle_coupled with ARM local timers for runtime,

	 * so there's probably no use for CLOCK_EVT_FEAT_DYNIRQ here.

	 */

	dev->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;

	dev->rating = 300;

	dev->features = features;

	dev->rating = rating;

	dev->set_next_event = dmtimer_set_next_event;

	dev->set_state_shutdown = dmtimer_clockevent_shutdown;

	dev->set_state_periodic = dmtimer_set_periodic;

	dev->set_state_oneshot = dmtimer_clockevent_shutdown;

	dev->set_state_oneshot_stopped = dmtimer_clockevent_shutdown;

	dev->tick_resume = dmtimer_clockevent_shutdown;

	dev->cpumask = cpu_possible_mask;

	dev->cpumask = cpumask;



	dev->irq = irq_of_parse_and_map(np, 0);

	if (!dev->irq) {

		error = -ENXIO;

		goto err_out_free;

	}

	if (!dev->irq)

		return -ENXIO;



	error = dmtimer_systimer_setup(np, &clkevt->t);

	if (error)

		goto err_out_free;

		return error;



	clkevt->period = 0xffffffff - DIV_ROUND_CLOSEST(t->rate, HZ);
@@ -578,32 +576,54 @@ static int __init dmtimer_clockevent_init(struct device_node *np) 
	writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl);



	error = request_irq(dev->irq, dmtimer_clockevent_interrupt,

			    IRQF_TIMER, "clockevent", clkevt);

			    IRQF_TIMER, name, clkevt);

	if (error)

		goto err_out_unmap;



	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->irq_ena);

	writel_relaxed(OMAP_TIMER_INT_OVERFLOW, t->base + t->wakeup);



	pr_info("TI gptimer clockevent: %s%lu Hz at %pOF\n",

		of_find_property(np, "ti,timer-alwon", NULL) ?

	pr_info("TI gptimer %s: %s%lu Hz at %pOF\n",

		name, of_find_property(np, "ti,timer-alwon", NULL) ?

		"always-on " : "", t->rate, np->parent);



	clockevents_config_and_register(dev, t->rate,

	return 0;



err_out_unmap:

	iounmap(t->base);



	return error;

}



static int __init dmtimer_clockevent_init(struct device_node *np)

{

	struct dmtimer_clockevent *clkevt;

	int error;



	clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);

	if (!clkevt)

		return -ENOMEM;



	error = dmtimer_clkevt_init_common(clkevt, np,

					   CLOCK_EVT_FEAT_PERIODIC |

					   CLOCK_EVT_FEAT_ONESHOT,

					   cpu_possible_mask, "clockevent",

					   300);

	if (error)

		goto err_out_free;



	clockevents_config_and_register(&clkevt->dev, clkevt->t.rate,

					3, /* Timer internal resync latency */

					0xffffffff);



	if (of_machine_is_compatible("ti,am33xx") ||

	    of_machine_is_compatible("ti,am43")) {

		dev->suspend = omap_clockevent_idle;

		dev->resume = omap_clockevent_unidle;

		clkevt->dev.suspend = omap_clockevent_idle;

		clkevt->dev.resume = omap_clockevent_unidle;

	}



	return 0;



err_out_unmap:

	iounmap(t->base);



err_out_free:

	kfree(clkevt);