Commit e005a9b3 authored by Doug Berger's avatar Doug Berger Committed by Alexandre Belloni
Browse files

rtc: brcmstb-waketimer: support level alarm_irq 



Some devices (e.g. BCM72112) use an alarm_irq interrupt that is
connected to a level interrupt controller rather than an edge
interrupt controller. In this case, the interrupt cannot be left
enabled by the irq handler while preserving the hardware wake-up
signal on wake capable devices or an interrupt storm will occur.

The alarm_expired flag is introduced to allow the disabling of
the interrupt when an alarm expires and to support balancing the
calls to disable_irq() and enable_irq() in accordance with the
existing design.

Fixes: 24304a87 ("rtc: brcmstb-waketimer: allow use as non-wake alarm")
Signed-off-by: default avatarDoug Berger <opendmb@gmail.com>
Reviewed-by: default avatarFlorian Fainelli <florian.fainelli@broadcom.com>
Link: https://lore.kernel.org/r/20230830224747.1663044-1-opendmb@gmail.com


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent d4277fa4

drivers/rtc/rtc-brcmstb-waketimer.c

+42 −5
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright © 2014-2017 Broadcom

 * Copyright © 2014-2023 Broadcom

 */



#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
@@ -34,6 +34,7 @@ struct brcmstb_waketmr { 
	u32 rate;

	unsigned long rtc_alarm;

	bool alarm_en;

	bool alarm_expired;

};



#define BRCMSTB_WKTMR_EVENT		0x00
@@ -64,6 +65,11 @@ static inline void brcmstb_waketmr_clear_alarm(struct brcmstb_waketmr *timer) 
	writel_relaxed(reg - 1, timer->base + BRCMSTB_WKTMR_ALARM);

	writel_relaxed(WKTMR_ALARM_EVENT, timer->base + BRCMSTB_WKTMR_EVENT);

	(void)readl_relaxed(timer->base + BRCMSTB_WKTMR_EVENT);

	if (timer->alarm_expired) {

		timer->alarm_expired = false;

		/* maintain call balance */

		enable_irq(timer->alarm_irq);

	}

}



static void brcmstb_waketmr_set_alarm(struct brcmstb_waketmr *timer,
@@ -105,10 +111,17 @@ static irqreturn_t brcmstb_alarm_irq(int irq, void *data) 
		return IRQ_HANDLED;



	if (timer->alarm_en) {

		if (!device_may_wakeup(timer->dev))

		if (device_may_wakeup(timer->dev)) {

			disable_irq_nosync(irq);

			timer->alarm_expired = true;

		} else {

			writel_relaxed(WKTMR_ALARM_EVENT,

				       timer->base + BRCMSTB_WKTMR_EVENT);

		}

		rtc_update_irq(timer->rtc, 1, RTC_IRQF | RTC_AF);

	} else {

		writel_relaxed(WKTMR_ALARM_EVENT,

			       timer->base + BRCMSTB_WKTMR_EVENT);

	}



	return IRQ_HANDLED;
@@ -221,8 +234,14 @@ static int brcmstb_waketmr_alarm_enable(struct device *dev, 
		    !brcmstb_waketmr_is_pending(timer))

			return -EINVAL;

		timer->alarm_en = true;

		if (timer->alarm_irq)

		if (timer->alarm_irq) {

			if (timer->alarm_expired) {

				timer->alarm_expired = false;

				/* maintain call balance */

				enable_irq(timer->alarm_irq);

			}

			enable_irq(timer->alarm_irq);

		}

	} else if (!enabled && timer->alarm_en) {

		if (timer->alarm_irq)

			disable_irq(timer->alarm_irq);
@@ -352,6 +371,17 @@ static int brcmstb_waketmr_suspend(struct device *dev) 
	return brcmstb_waketmr_prepare_suspend(timer);

}



static int brcmstb_waketmr_suspend_noirq(struct device *dev)

{

	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);



	/* Catch any alarms occurring prior to noirq */

	if (timer->alarm_expired && device_may_wakeup(dev))

		return -EBUSY;



	return 0;

}



static int brcmstb_waketmr_resume(struct device *dev)

{

	struct brcmstb_waketmr *timer = dev_get_drvdata(dev);
@@ -368,10 +398,17 @@ static int brcmstb_waketmr_resume(struct device *dev) 


	return ret;

}

#else

#define brcmstb_waketmr_suspend		NULL

#define brcmstb_waketmr_suspend_noirq	NULL

#define brcmstb_waketmr_resume		NULL

#endif /* CONFIG_PM_SLEEP */



static SIMPLE_DEV_PM_OPS(brcmstb_waketmr_pm_ops,

			 brcmstb_waketmr_suspend, brcmstb_waketmr_resume);

static const struct dev_pm_ops brcmstb_waketmr_pm_ops = {

	.suspend	= brcmstb_waketmr_suspend,

	.suspend_noirq	= brcmstb_waketmr_suspend_noirq,

	.resume		= brcmstb_waketmr_resume,

};



static const __maybe_unused struct of_device_id brcmstb_waketmr_of_match[] = {

	{ .compatible = "brcm,brcmstb-waketimer" },