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Commit a9422a19 authored by Maxime Ripard's avatar Maxime Ripard Committed by Alexandre Belloni
Browse files

rtc: sun6i: Add some locking 



Some registers have a read-modify-write access pattern that are not atomic.

Add some locking to prevent from concurrent accesses.

Cc: stable@vger.kernel.org
Acked-by: default avatarChen-Yu Tsai <wens@csie.org>
Signed-off-by: default avatarMaxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 37539414

drivers/rtc/rtc-sun6i.c

+15 −2
Original line number Diff line number Diff line
@@ -114,13 +114,17 @@ struct sun6i_rtc_dev { 
	void __iomem *base;

	int irq;

	unsigned long alarm;



	spinlock_t lock;

};



static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id)

{

	struct sun6i_rtc_dev *chip = (struct sun6i_rtc_dev *) id;

	irqreturn_t ret = IRQ_NONE;

	u32 val;



	spin_lock(&chip->lock);

	val = readl(chip->base + SUN6I_ALRM_IRQ_STA);



	if (val & SUN6I_ALRM_IRQ_STA_CNT_IRQ_PEND) {
@@ -129,10 +133,11 @@ static irqreturn_t sun6i_rtc_alarmirq(int irq, void *id) 


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



		return IRQ_HANDLED;

		ret = IRQ_HANDLED;

	}

	spin_unlock(&chip->lock);



	return IRQ_NONE;

	return ret;

}



static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip)
@@ -140,6 +145,7 @@ static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip) 
	u32 alrm_val = 0;

	u32 alrm_irq_val = 0;

	u32 alrm_wake_val = 0;

	unsigned long flags;



	if (to) {

		alrm_val = SUN6I_ALRM_EN_CNT_EN;
@@ -150,9 +156,11 @@ static void sun6i_rtc_setaie(int to, struct sun6i_rtc_dev *chip) 
		       chip->base + SUN6I_ALRM_IRQ_STA);

	}



	spin_lock_irqsave(&chip->lock, flags);

	writel(alrm_val, chip->base + SUN6I_ALRM_EN);

	writel(alrm_irq_val, chip->base + SUN6I_ALRM_IRQ_EN);

	writel(alrm_wake_val, chip->base + SUN6I_ALARM_CONFIG);

	spin_unlock_irqrestore(&chip->lock, flags);

}



static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm)
@@ -191,11 +199,15 @@ static int sun6i_rtc_gettime(struct device *dev, struct rtc_time *rtc_tm) 
static int sun6i_rtc_getalarm(struct device *dev, struct rtc_wkalrm *wkalrm)

{

	struct sun6i_rtc_dev *chip = dev_get_drvdata(dev);

	unsigned long flags;

	u32 alrm_st;

	u32 alrm_en;



	spin_lock_irqsave(&chip->lock, flags);

	alrm_en = readl(chip->base + SUN6I_ALRM_IRQ_EN);

	alrm_st = readl(chip->base + SUN6I_ALRM_IRQ_STA);

	spin_unlock_irqrestore(&chip->lock, flags);



	wkalrm->enabled = !!(alrm_en & SUN6I_ALRM_EN_CNT_EN);

	wkalrm->pending = !!(alrm_st & SUN6I_ALRM_EN_CNT_EN);

	rtc_time_to_tm(chip->alarm, &wkalrm->time);
@@ -356,6 +368,7 @@ static int sun6i_rtc_probe(struct platform_device *pdev) 
	chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);

	if (!chip)

		return -ENOMEM;

	spin_lock_init(&chip->lock);



	platform_set_drvdata(pdev, chip);

	chip->dev = &pdev->dev;