Commit af69a180 authored by Atsushi Nemoto's avatar Atsushi Nemoto Committed by Linus Torvalds
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rtc-tx4939: fix races around device registration 



* Use its own spinlock instead of rtc->irq_lock
* Check pdata->rtc before calling rtc_update_irq
* Disable interrupt after rtc_device_unregister

Signed-off-by: default avatarAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: default avatarAlessandro Zummo <a.zummo@towertech.it>
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 ba4f3e47

drivers/rtc/rtc-tx4939.c

+26 −25
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
struct tx4939rtc_plat_data {

	struct rtc_device *rtc;

	struct tx4939_rtc_reg __iomem *rtcreg;

	spinlock_t lock;

};



static struct tx4939rtc_plat_data *get_tx4939rtc_plat_data(struct device *dev)
@@ -52,14 +53,14 @@ static int tx4939_rtc_set_mmss(struct device *dev, unsigned long secs) 
	buf[3] = secs >> 8;

	buf[4] = secs >> 16;

	buf[5] = secs >> 24;

	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	__raw_writel(0, &rtcreg->adr);

	for (i = 0; i < 6; i++)

		__raw_writel(buf[i], &rtcreg->dat);

	ret = tx4939_rtc_cmd(rtcreg,

			     TX4939_RTCCTL_COMMAND_SETTIME |

			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	return ret;

}
@@ -71,18 +72,18 @@ static int tx4939_rtc_read_time(struct device *dev, struct rtc_time *tm) 
	unsigned long sec;

	unsigned char buf[6];



	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	ret = tx4939_rtc_cmd(rtcreg,

			     TX4939_RTCCTL_COMMAND_GETTIME |

			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));

	if (ret) {

		spin_unlock_irq(&pdata->rtc->irq_lock);

		spin_unlock_irq(&pdata->lock);

		return ret;

	}

	__raw_writel(2, &rtcreg->adr);

	for (i = 2; i < 6; i++)

		buf[i] = __raw_readl(&rtcreg->dat);

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];

	rtc_time_to_tm(sec, tm);

	return rtc_valid_tm(tm);
@@ -110,13 +111,13 @@ static int tx4939_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) 
	buf[3] = sec >> 8;

	buf[4] = sec >> 16;

	buf[5] = sec >> 24;

	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	__raw_writel(0, &rtcreg->adr);

	for (i = 0; i < 6; i++)

		__raw_writel(buf[i], &rtcreg->dat);

	ret = tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_SETALARM |

			     (alrm->enabled ? TX4939_RTCCTL_ALME : 0));

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	return ret;

}
@@ -129,12 +130,12 @@ static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 
	unsigned char buf[6];

	u32 ctl;



	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	ret = tx4939_rtc_cmd(rtcreg,

			     TX4939_RTCCTL_COMMAND_GETALARM |

			     (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALME));

	if (ret) {

		spin_unlock_irq(&pdata->rtc->irq_lock);

		spin_unlock_irq(&pdata->lock);

		return ret;

	}

	__raw_writel(2, &rtcreg->adr);
@@ -143,7 +144,7 @@ static int tx4939_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) 
	ctl = __raw_readl(&rtcreg->ctl);

	alrm->enabled = (ctl & TX4939_RTCCTL_ALME) ? 1 : 0;

	alrm->pending = (ctl & TX4939_RTCCTL_ALMD) ? 1 : 0;

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	sec = (buf[5] << 24) | (buf[4] << 16) | (buf[3] << 8) | buf[2];

	rtc_time_to_tm(sec, &alrm->time);

	return rtc_valid_tm(&alrm->time);
@@ -153,11 +154,11 @@ static int tx4939_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) 
{

	struct tx4939rtc_plat_data *pdata = get_tx4939rtc_plat_data(dev);



	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	tx4939_rtc_cmd(pdata->rtcreg,

		       TX4939_RTCCTL_COMMAND_NOP |

		       (enabled ? TX4939_RTCCTL_ALME : 0));

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	return 0;

}
@@ -167,12 +168,13 @@ static irqreturn_t tx4939_rtc_interrupt(int irq, void *dev_id) 
	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;

	unsigned long events = RTC_IRQF;



	spin_lock(&pdata->rtc->irq_lock);

	spin_lock(&pdata->lock);

	if (__raw_readl(&rtcreg->ctl) & TX4939_RTCCTL_ALMD) {

		events |= RTC_AF;

		tx4939_rtc_cmd(rtcreg, TX4939_RTCCTL_COMMAND_NOP);

	}

	spin_unlock(&pdata->rtc->irq_lock);

	spin_unlock(&pdata->lock);

	if (likely(pdata->rtc))

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

	return IRQ_HANDLED;

}
@@ -194,13 +196,13 @@ static ssize_t tx4939_rtc_nvram_read(struct kobject *kobj, 
	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;

	ssize_t count;



	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;

	     count++, size--) {

		__raw_writel(pos++, &rtcreg->adr);

		*buf++ = __raw_readl(&rtcreg->dat);

	}

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	return count;

}
@@ -213,13 +215,13 @@ static ssize_t tx4939_rtc_nvram_write(struct kobject *kobj, 
	struct tx4939_rtc_reg __iomem *rtcreg = pdata->rtcreg;

	ssize_t count;



	spin_lock_irq(&pdata->rtc->irq_lock);

	spin_lock_irq(&pdata->lock);

	for (count = 0; size > 0 && pos < TX4939_RTC_REG_RAMSIZE;

	     count++, size--) {

		__raw_writel(pos++, &rtcreg->adr);

		__raw_writel(*buf++, &rtcreg->dat);

	}

	spin_unlock_irq(&pdata->rtc->irq_lock);

	spin_unlock_irq(&pdata->lock);

	return count;

}
@@ -259,6 +261,7 @@ static int __init tx4939_rtc_probe(struct platform_device *pdev) 
	if (!pdata->rtcreg)

		return -EBUSY;



	spin_lock_init(&pdata->lock);

	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);

	if (devm_request_irq(&pdev->dev, irq, tx4939_rtc_interrupt,

			     IRQF_DISABLED, pdev->name, &pdev->dev) < 0)
@@ -277,14 +280,12 @@ static int __init tx4939_rtc_probe(struct platform_device *pdev) 
static int __exit tx4939_rtc_remove(struct platform_device *pdev)

{

	struct tx4939rtc_plat_data *pdata = platform_get_drvdata(pdev);

	struct rtc_device *rtc = pdata->rtc;



	spin_lock_irq(&rtc->irq_lock);

	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);

	spin_unlock_irq(&rtc->irq_lock);

	sysfs_remove_bin_file(&pdev->dev.kobj, &tx4939_rtc_nvram_attr);

	rtc_device_unregister(rtc);

	platform_set_drvdata(pdev, NULL);

	rtc_device_unregister(pdata->rtc);

	spin_lock_irq(&pdata->lock);

	tx4939_rtc_cmd(pdata->rtcreg, TX4939_RTCCTL_COMMAND_NOP);

	spin_unlock_irq(&pdata->lock);

	return 0;

}

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