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From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
To: Alessandro Zummo <alessandro.zummo@towertech.it>
CC: "Sharp, Andy" <Andy.Sharp@lsi.com>, Thomas Hommel
	<thomas.hommel@gefanuc.com>, "rtc-linux@googlegroups.com"
	<rtc-linux@googlegroups.com>, "linux-kernel@vger.kernel.org"
	<linux-kernel@vger.kernel.org>, "akpm@linux-foundation.org"
	<akpm@linux-foundation.org>
Date: Sun, 11 Oct 2009 11:50:45 -0600
Subject: [PATCH 2/2] rtc-stk17ta8: Fix races around device registration
Thread-Topic: [PATCH 2/2] rtc-stk17ta8: Fix races around device registration
Thread-Index: AcpKm2McEUEHOLT9Sa+AT1+XvFobFQ==
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* Call dev_set_drvdata before rtc device creation
* Use its own spinlock instead of rtc->irq_lock
* Check pdata->rtc before calling rtc_update_irq
* Use alarm_irq_enable and remove ioctl routine
* Use devres APIs and simplify error/remove path

These fixes are ported from ds1553 driver and just compile-tested only.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
---
 drivers/rtc/rtc-stk17ta8.c |  113 +++++++++++++++++-----------------------=
---
 1 files changed, 45 insertions(+), 68 deletions(-)

diff --git a/drivers/rtc/rtc-stk17ta8.c b/drivers/rtc/rtc-stk17ta8.c
index 7d1547b..944e989 100644
--- a/drivers/rtc/rtc-stk17ta8.c
+++ b/drivers/rtc/rtc-stk17ta8.c
@@ -62,7 +62,6 @@
 struct rtc_plat_data {
 	struct rtc_device *rtc;
 	void __iomem *ioaddr;
-	unsigned long baseaddr;
 	unsigned long last_jiffies;
 	int irq;
 	unsigned int irqen;
@@ -70,6 +69,7 @@ struct rtc_plat_data {
 	int alrm_min;
 	int alrm_hour;
 	int alrm_mday;
+	spinlock_t lock;
 };
=20
 static int stk17ta8_rtc_set_time(struct device *dev, struct rtc_time *tm)
@@ -142,7 +142,7 @@ static void stk17ta8_rtc_update_alarm(struct rtc_plat_d=
ata *pdata)
 	unsigned long irqflags;
 	u8 flags;
=20
-	spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags);
+	spin_lock_irqsave(&pdata->lock, irqflags);
=20
 	flags =3D readb(ioaddr + RTC_FLAGS);
 	writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
@@ -162,7 +162,7 @@ static void stk17ta8_rtc_update_alarm(struct rtc_plat_d=
ata *pdata)
 	writeb(pdata->irqen ? RTC_INTS_AIE : 0, ioaddr + RTC_INTERRUPTS);
 	readb(ioaddr + RTC_FLAGS);	/* clear interrupts */
 	writeb(flags & ~RTC_WRITE, ioaddr + RTC_FLAGS);
-	spin_unlock_irqrestore(&pdata->rtc->irq_lock, irqflags);
+	spin_unlock_irqrestore(&pdata->lock, irqflags);
 }
=20
 static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *a=
lrm)
@@ -202,48 +202,45 @@ static irqreturn_t stk17ta8_rtc_interrupt(int irq, vo=
id *dev_id)
 	struct platform_device *pdev =3D dev_id;
 	struct rtc_plat_data *pdata =3D platform_get_drvdata(pdev);
 	void __iomem *ioaddr =3D pdata->ioaddr;
-	unsigned long events =3D RTC_IRQF;
+	unsigned long events =3D 0;
=20
+	spin_lock(&pdata->lock);
 	/* read and clear interrupt */
-	if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))
-		return IRQ_NONE;
-	if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
-		events |=3D RTC_UF;
-	else
-		events |=3D RTC_AF;
-	rtc_update_irq(pdata->rtc, 1, events);
-	return IRQ_HANDLED;
+	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {
+		events =3D RTC_IRQF;
+		if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)
+			events |=3D RTC_UF;
+		else
+			events |=3D RTC_AF;
+		if (likely(pdata->rtc))
+			rtc_update_irq(pdata->rtc, 1, events);
+	}
+	spin_unlock(&pdata->lock);
+	return events ? IRQ_HANDLED : IRQ_NONE;
 }
=20
-static int stk17ta8_rtc_ioctl(struct device *dev, unsigned int cmd,
-			    unsigned long arg)
+static int stk17ta8_rtc_alarm_irq_enable(struct device *dev,
+	unsigned int enabled)
 {
 	struct platform_device *pdev =3D to_platform_device(dev);
 	struct rtc_plat_data *pdata =3D platform_get_drvdata(pdev);
=20
 	if (pdata->irq <=3D 0)
-		return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */
-	switch (cmd) {
-	case RTC_AIE_OFF:
+		return -EINVAL;
+	if (enabled)
+ 		pdata->irqen |=3D RTC_AF;
+	else
 		pdata->irqen &=3D ~RTC_AF;
-		stk17ta8_rtc_update_alarm(pdata);
-		break;
-	case RTC_AIE_ON:
-		pdata->irqen |=3D RTC_AF;
-		stk17ta8_rtc_update_alarm(pdata);
-		break;
-	default:
-		return -ENOIOCTLCMD;
-	}
+	stk17ta8_rtc_update_alarm(pdata);
 	return 0;
 }
=20
 static const struct rtc_class_ops stk17ta8_rtc_ops =3D {
-	.read_time	=3D stk17ta8_rtc_read_time,
-	.set_time	=3D stk17ta8_rtc_set_time,
-	.read_alarm	=3D stk17ta8_rtc_read_alarm,
-	.set_alarm	=3D stk17ta8_rtc_set_alarm,
-	.ioctl		=3D stk17ta8_rtc_ioctl,
+	.read_time		=3D stk17ta8_rtc_read_time,
+	.set_time		=3D stk17ta8_rtc_set_time,
+	.read_alarm		=3D stk17ta8_rtc_read_alarm,
+	.set_alarm		=3D stk17ta8_rtc_set_alarm,
+	.alarm_irq_enable	=3D stk17ta8_rtc_alarm_irq_enable,
 };
=20
 static ssize_t stk17ta8_nvram_read(struct kobject *kobj,
@@ -293,26 +290,22 @@ static int __init stk17ta8_rtc_probe(struct platform_=
device *pdev)
 	unsigned int cal;
 	unsigned int flags;
 	struct rtc_plat_data *pdata;
-	void __iomem *ioaddr =3D NULL;
+	void __iomem *ioaddr;
 	int ret =3D 0;
=20
 	res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENODEV;
=20
-	pdata =3D kzalloc(sizeof(*pdata), GFP_KERNEL);
+	pdata =3D devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
-	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {
-		ret =3D -EBUSY;
-		goto out;
-	}
-	pdata->baseaddr =3D res->start;
-	ioaddr =3D ioremap(pdata->baseaddr, RTC_REG_SIZE);
-	if (!ioaddr) {
-		ret =3D -ENOMEM;
-		goto out;
-	}
+	if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,
+			pdev->name))
+		return -EBUSY;
+	ioaddr =3D devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);
+	if (!ioaddr)
+		return -ENOMEM;
 	pdata->ioaddr =3D ioaddr;
 	pdata->irq =3D platform_get_irq(pdev, 0);
=20
@@ -328,9 +321,13 @@ static int __init stk17ta8_rtc_probe(struct platform_d=
evice *pdev)
 	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)
 		dev_warn(&pdev->dev, "voltage-low detected.\n");
=20
+	spin_lock_init(&pdata->lock);
+	pdata->last_jiffies =3D jiffies;
+	platform_set_drvdata(pdev, pdata);
 	if (pdata->irq > 0) {
 		writeb(0, ioaddr + RTC_INTERRUPTS);
-		if (request_irq(pdata->irq, stk17ta8_rtc_interrupt,
+		if (devm_request_irq(&pdev->dev, pdata->irq,
+				stk17ta8_rtc_interrupt,
 				IRQF_DISABLED | IRQF_SHARED,
 				pdev->name, pdev) < 0) {
 			dev_warn(&pdev->dev, "interrupt not available.\n");
@@ -340,27 +337,12 @@ static int __init stk17ta8_rtc_probe(struct platform_=
device *pdev)
=20
 	rtc =3D rtc_device_register(pdev->name, &pdev->dev,
 				  &stk17ta8_rtc_ops, THIS_MODULE);
-	if (IS_ERR(rtc)) {
-		ret =3D PTR_ERR(rtc);
-		goto out;
-	}
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
 	pdata->rtc =3D rtc;
-	pdata->last_jiffies =3D jiffies;
-	platform_set_drvdata(pdev, pdata);
 	ret =3D sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 	if (ret)
-		goto out;
-	return 0;
- out:
-	if (pdata->rtc)
-		rtc_device_unregister(pdata->rtc);
-	if (pdata->irq > 0)
-		free_irq(pdata->irq, pdev);
-	if (ioaddr)
-		iounmap(ioaddr);
-	if (pdata->baseaddr)
-		release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
-	kfree(pdata);
+		rtc_device_unregister(rtc);
 	return ret;
 }
=20
@@ -370,13 +352,8 @@ static int __devexit stk17ta8_rtc_remove(struct platfo=
rm_device *pdev)
=20
 	sysfs_remove_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);
 	rtc_device_unregister(pdata->rtc);
-	if (pdata->irq > 0) {
+	if (pdata->irq > 0)
 		writeb(0, pdata->ioaddr + RTC_INTERRUPTS);
-		free_irq(pdata->irq, pdev);
-	}
-	iounmap(pdata->ioaddr);
-	release_mem_region(pdata->baseaddr, RTC_REG_SIZE);
-	kfree(pdata);
 	return 0;
 }
=20
--=20
1.5.6.5

