linux-kernel - [PATCH v2 2/2] rtc: asm9260: rework locking

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Message-Id: <20160831161528.11217-2-alexandre.belloni@free-electrons.com>
Date:   Wed, 31 Aug 2016 18:15:28 +0200
From:   Alexandre Belloni <alexandre.belloni@...e-electrons.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>
Cc:     Oleksij Rempel <linux@...pel-privat.de>,
        rtc-linux@...glegroups.com, linux-kernel@...r.kernel.org,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>
Subject: [PATCH v2 2/2] rtc: asm9260: rework locking

The rtc-asm9260 driver uses a discrete spinlock (wrongly uninitialized).
Use the rtc mutex to lock mmio accesses instead.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...e-electrons.com>
---
 drivers/rtc/rtc-asm9260.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/drivers/rtc/rtc-asm9260.c b/drivers/rtc/rtc-asm9260.c
index 5219916ce11d..18a93d3e3f93 100644
--- a/drivers/rtc/rtc-asm9260.c
+++ b/drivers/rtc/rtc-asm9260.c
@@ -112,8 +112,6 @@ struct asm9260_rtc_priv {
 	void __iomem		*iobase;
 	struct rtc_device	*rtc;
 	struct clk		*clk;
-	/* io lock */
-	spinlock_t		lock;
 };
 
 static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
@@ -122,11 +120,15 @@ static irqreturn_t asm9260_rtc_irq(int irq, void *dev_id)
 	u32 isr;
 	unsigned long events = 0;
 
+	mutex_lock(&priv->rtc->ops_lock);
 	isr = ioread32(priv->iobase + HW_CIIR);
-	if (!isr)
+	if (!isr) {
+		mutex_unlock(&priv->rtc->ops_lock);
 		return IRQ_NONE;
+	}
 
 	iowrite32(0, priv->iobase + HW_CIIR);
+	mutex_unlock(&priv->rtc->ops_lock);
 
 	events |= RTC_AF | RTC_IRQF;
 
@@ -139,9 +141,7 @@ static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
 	u32 ctime0, ctime1, ctime2;
-	unsigned long irq_flags;
 
-	spin_lock_irqsave(&priv->lock, irq_flags);
 	ctime0 = ioread32(priv->iobase + HW_CTIME0);
 	ctime1 = ioread32(priv->iobase + HW_CTIME1);
 	ctime2 = ioread32(priv->iobase + HW_CTIME2);
@@ -155,7 +155,6 @@ static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
 		ctime1 = ioread32(priv->iobase + HW_CTIME1);
 		ctime2 = ioread32(priv->iobase + HW_CTIME2);
 	}
-	spin_unlock_irqrestore(&priv->lock, irq_flags);
 
 	tm->tm_sec  = (ctime0 >> BM_CTIME0_SEC_S)  & BM_CTIME0_SEC_M;
 	tm->tm_min  = (ctime0 >> BM_CTIME0_MIN_S)  & BM_CTIME0_MIN_M;
@@ -174,9 +173,7 @@ static int asm9260_rtc_read_time(struct device *dev, struct rtc_time *tm)
 static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
-	unsigned long irq_flags;
 
-	spin_lock_irqsave(&priv->lock, irq_flags);
 	/*
 	 * make sure SEC counter will not flip other counter on write time,
 	 * real value will be written at the enf of sequence.
@@ -191,7 +188,6 @@ static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	iowrite32(tm->tm_hour, priv->iobase + HW_HOUR);
 	iowrite32(tm->tm_min,  priv->iobase + HW_MIN);
 	iowrite32(tm->tm_sec,  priv->iobase + HW_SEC);
-	spin_unlock_irqrestore(&priv->lock, irq_flags);
 
 	return 0;
 }
@@ -199,9 +195,7 @@ static int asm9260_rtc_set_time(struct device *dev, struct rtc_time *tm)
 static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
-	unsigned long irq_flags;
 
-	spin_lock_irqsave(&priv->lock, irq_flags);
 	alrm->time.tm_year = ioread32(priv->iobase + HW_ALYEAR);
 	alrm->time.tm_mon  = ioread32(priv->iobase + HW_ALMON);
 	alrm->time.tm_mday = ioread32(priv->iobase + HW_ALDOM);
@@ -213,7 +207,6 @@ static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 
 	alrm->enabled = ioread32(priv->iobase + HW_AMR) ? 1 : 0;
 	alrm->pending = ioread32(priv->iobase + HW_CIIR) ? 1 : 0;
-	spin_unlock_irqrestore(&priv->lock, irq_flags);
 
 	return rtc_valid_tm(&alrm->time);
 }
@@ -221,9 +214,7 @@ static int asm9260_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
 	struct asm9260_rtc_priv *priv = dev_get_drvdata(dev);
-	unsigned long irq_flags;
 
-	spin_lock_irqsave(&priv->lock, irq_flags);
 	iowrite32(alrm->time.tm_year, priv->iobase + HW_ALYEAR);
 	iowrite32(alrm->time.tm_mon,  priv->iobase + HW_ALMON);
 	iowrite32(alrm->time.tm_mday, priv->iobase + HW_ALDOM);
@@ -234,7 +225,6 @@ static int asm9260_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 	iowrite32(alrm->time.tm_sec,  priv->iobase + HW_ALSEC);
 
 	iowrite32(alrm->enabled ? 0 : BM_AMR_OFF, priv->iobase + HW_AMR);
-	spin_unlock_irqrestore(&priv->lock, irq_flags);
 
 	return 0;
 }
-- 
2.9.3