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authorMaxime Ripard <maxime.ripard@free-electrons.com>2017-01-23 11:41:47 +0100
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2017-02-01 12:42:39 +0100
commita9422a19ce270a22fc520f2278fb7e80c58be508 (patch)
tree6507b1553c16b5b20a87eed7b7015e3b07cfa910 /drivers/rtc/rtc-sun6i.c
parent3753941475ae6501dcd1e41832bd0e6c35247d6a (diff)
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: Chen-Yu Tsai <wens@csie.org> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'drivers/rtc/rtc-sun6i.c')
-rw-r--r--drivers/rtc/rtc-sun6i.c17
1 files changed, 15 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-sun6i.c b/drivers/rtc/rtc-sun6i.c
index a6136cb99851..72086f0c0782 100644
--- a/drivers/rtc/rtc-sun6i.c
+++ b/drivers/rtc/rtc-sun6i.c
@@ -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;