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Commit 3151520d authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Linus Torvalds
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rtc-stk17ta8: fix races around device registration 



- Call dev_set_drvdata before rtc device creation.

- Use its own spinlock instead of rtc->irq_lock.  Because pdata->rtc
  must be initialized to use the irq_lock (pdata->rtc->irq_lock).  There
  is a small window which rtc methods can be called before pdata->rtc is
  initialized.

  And there is no need use the irq_lock to protect hardware registers.
  The driver's own spinlock shoule be enough.

- 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: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Cc: Thomas Hommel <thomas.hommel@gefanuc.com>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ac18eb62

drivers/rtc/rtc-stk17ta8.c

+45 −69
Original line number Diff line number Diff line
@@ -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;

};



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_data *pdata) 
	unsigned long irqflags;

	u8 flags;



	spin_lock_irqsave(&pdata->rtc->irq_lock, irqflags);

	spin_lock_irqsave(&pdata->lock, irqflags);



	flags = readb(ioaddr + RTC_FLAGS);

	writeb(flags | RTC_WRITE, ioaddr + RTC_FLAGS);
@@ -162,7 +162,7 @@ static void stk17ta8_rtc_update_alarm(struct rtc_plat_data *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);

}



static int stk17ta8_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
@@ -202,39 +202,36 @@ static irqreturn_t stk17ta8_rtc_interrupt(int irq, void *dev_id) 
	struct platform_device *pdev = dev_id;

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);

	void __iomem *ioaddr = pdata->ioaddr;

	unsigned long events = RTC_IRQF;

	unsigned long events = 0;



	spin_lock(&pdata->lock);

	/* read and clear interrupt */

	if (!(readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF))

		return IRQ_NONE;

	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_AF) {

		events = RTC_IRQF;

		if (readb(ioaddr + RTC_SECONDS_ALARM) & 0x80)

			events |= RTC_UF;

		else

			events |= RTC_AF;

		if (likely(pdata->rtc))

			rtc_update_irq(pdata->rtc, 1, events);

	return IRQ_HANDLED;

	}

	spin_unlock(&pdata->lock);

	return events ? IRQ_HANDLED : IRQ_NONE;

}



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 = to_platform_device(dev);

	struct rtc_plat_data *pdata = platform_get_drvdata(pdev);



	if (pdata->irq <= 0)

		return -ENOIOCTLCMD; /* fall back into rtc-dev's emulation */

	switch (cmd) {

	case RTC_AIE_OFF:

		pdata->irqen &= ~RTC_AF;

		stk17ta8_rtc_update_alarm(pdata);

		break;

	case RTC_AIE_ON:

		return -EINVAL;

	if (enabled)

		pdata->irqen |= RTC_AF;

	else

		pdata->irqen &= ~RTC_AF;

	stk17ta8_rtc_update_alarm(pdata);

		break;

	default:

		return -ENOIOCTLCMD;

	}

	return 0;

}
@@ -243,7 +240,7 @@ static const struct rtc_class_ops stk17ta8_rtc_ops = { 
	.set_time		= stk17ta8_rtc_set_time,

	.read_alarm		= stk17ta8_rtc_read_alarm,

	.set_alarm		= stk17ta8_rtc_set_alarm,

	.ioctl		= stk17ta8_rtc_ioctl,

	.alarm_irq_enable	= stk17ta8_rtc_alarm_irq_enable,

};



static ssize_t stk17ta8_nvram_read(struct kobject *kobj,
@@ -292,26 +289,22 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) 
	unsigned int cal;

	unsigned int flags;

	struct rtc_plat_data *pdata;

	void __iomem *ioaddr = NULL;

	void __iomem *ioaddr;

	int ret = 0;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENODEV;



	pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);

	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);

	if (!pdata)

		return -ENOMEM;

	if (!request_mem_region(res->start, RTC_REG_SIZE, pdev->name)) {

		ret = -EBUSY;

		goto out;

	}

	pdata->baseaddr = res->start;

	ioaddr = ioremap(pdata->baseaddr, RTC_REG_SIZE);

	if (!ioaddr) {

		ret = -ENOMEM;

		goto out;

	}

	if (!devm_request_mem_region(&pdev->dev, res->start, RTC_REG_SIZE,

			pdev->name))

		return -EBUSY;

	ioaddr = devm_ioremap(&pdev->dev, res->start, RTC_REG_SIZE);

	if (!ioaddr)

		return -ENOMEM;

	pdata->ioaddr = ioaddr;

	pdata->irq = platform_get_irq(pdev, 0);
@@ -327,9 +320,13 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) 
	if (readb(ioaddr + RTC_FLAGS) & RTC_FLAGS_PF)

		dev_warn(&pdev->dev, "voltage-low detected.\n");



	spin_lock_init(&pdata->lock);

	pdata->last_jiffies = 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");
@@ -337,30 +334,14 @@ static int __devinit stk17ta8_rtc_probe(struct platform_device *pdev) 
		}

	}



	pdata->last_jiffies = jiffies;

	platform_set_drvdata(pdev, pdata);



	pdata->rtc = rtc_device_register(pdev->name, &pdev->dev,

				  &stk17ta8_rtc_ops, THIS_MODULE);

	if (IS_ERR(pdata->rtc)) {

		ret = PTR_ERR(pdata->rtc);

		goto out;

	}

	if (IS_ERR(pdata->rtc))

		return PTR_ERR(pdata->rtc);



	ret = sysfs_create_bin_file(&pdev->dev.kobj, &stk17ta8_nvram_attr);

	if (ret) {

	if (ret)

		rtc_device_unregister(pdata->rtc);

		goto out;

	}

	return 0;

 out:

	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);

	return ret;

}
@@ -370,13 +351,8 @@ static int __devexit stk17ta8_rtc_remove(struct platform_device *pdev) 


	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;

}