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Commit bcd9b89c authored by David Brownell's avatar David Brownell Committed by Linus Torvalds
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[PATCH] rtc-cmos lockdep fix, irq updates 



Lockdep reported cmos_suspend() and cmos_resume() calling rtc_update_irq()
with IRQs enabled; not allowed.

Also fix problems seen on some hardware, whereby false alarm IRQs could be
reported (primarily to userspace); and update two comments to match changes
in ACPI.  Those make up most of this patch, by volume.

Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a2b091db

drivers/rtc/rtc-cmos.c

+33 −17
Original line number Diff line number Diff line
@@ -59,6 +59,19 @@ struct cmos_rtc { 


static const char driver_name[] = "rtc_cmos";



/* The RTC_INTR register may have e.g. RTC_PF set even if RTC_PIE is clear;

 * always mask it against the irq enable bits in RTC_CONTROL.  Bit values

 * are the same: PF==PIE, AF=AIE, UF=UIE; so RTC_IRQMASK works with both.

 */

#define	RTC_IRQMASK	(RTC_PF | RTC_AF | RTC_UF)



static inline int is_intr(u8 rtc_intr)

{

	if (!(rtc_intr & RTC_IRQF))

		return 0;

	return rtc_intr & RTC_IRQMASK;

}



/*----------------------------------------------------------------*/



static int cmos_read_time(struct device *dev, struct rtc_time *t)
@@ -188,7 +201,8 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) 
	rtc_control &= ~RTC_AIE;

	CMOS_WRITE(rtc_control, RTC_CONTROL);

	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);

	if (rtc_intr)

	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;

	if (is_intr(rtc_intr))

		rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);



	/* update alarm */
@@ -207,7 +221,8 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t) 
		rtc_control |= RTC_AIE;

		CMOS_WRITE(rtc_control, RTC_CONTROL);

		rtc_intr = CMOS_READ(RTC_INTR_FLAGS);

		if (rtc_intr)

		rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;

		if (is_intr(rtc_intr))

			rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);

	}
@@ -287,7 +302,8 @@ cmos_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) 
	}

	CMOS_WRITE(rtc_control, RTC_CONTROL);

	rtc_intr = CMOS_READ(RTC_INTR_FLAGS);

	if (rtc_intr)

	rtc_intr &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;

	if (is_intr(rtc_intr))

		rtc_update_irq(&cmos->rtc->class_dev, 1, rtc_intr);

	spin_unlock_irqrestore(&rtc_lock, flags);

	return 0;
@@ -353,12 +369,10 @@ static irqreturn_t cmos_interrupt(int irq, void *p) 


	spin_lock(&rtc_lock);

	irqstat = CMOS_READ(RTC_INTR_FLAGS);

	irqstat &= (CMOS_READ(RTC_CONTROL) & RTC_IRQMASK) | RTC_IRQF;

	spin_unlock(&rtc_lock);



	if (irqstat) {

		/* NOTE: irqstat may have e.g. RTC_PF set

		 * even when RTC_PIE is clear...

		 */

	if (is_intr(irqstat)) {

		rtc_update_irq(p, 1, irqstat);

		return IRQ_HANDLED;

	} else
@@ -525,24 +539,25 @@ static int cmos_suspend(struct device *dev, pm_message_t mesg) 
{

	struct cmos_rtc	*cmos = dev_get_drvdata(dev);

	int		do_wake = device_may_wakeup(dev);

	unsigned char	tmp, irqstat;

	unsigned char	tmp;



	/* only the alarm might be a wakeup event source */

	spin_lock_irq(&rtc_lock);

	cmos->suspend_ctrl = tmp = CMOS_READ(RTC_CONTROL);

	if (tmp & (RTC_PIE|RTC_AIE|RTC_UIE)) {

		unsigned char	irqstat;



		if (do_wake)

			tmp &= ~(RTC_PIE|RTC_UIE);

		else

			tmp &= ~(RTC_PIE|RTC_AIE|RTC_UIE);

		CMOS_WRITE(tmp, RTC_CONTROL);

		irqstat = CMOS_READ(RTC_INTR_FLAGS);

	} else

		irqstat = 0;

	spin_unlock_irq(&rtc_lock);



	if (irqstat)

		irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;

		if (is_intr(irqstat))

			rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat);

	}

	spin_unlock_irq(&rtc_lock);



	/* ACPI HOOK:  enable ACPI_EVENT_RTC when (tmp & RTC_AIE)

	 * ... it'd be best if we could do that under rtc_lock.
@@ -573,9 +588,10 @@ static int cmos_resume(struct device *dev) 
		spin_lock_irq(&rtc_lock);

		CMOS_WRITE(tmp, RTC_CONTROL);

		tmp = CMOS_READ(RTC_INTR_FLAGS);

		spin_unlock_irq(&rtc_lock);

		if (tmp)

		tmp &= (cmos->suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;

		if (is_intr(tmp))

			rtc_update_irq(&cmos->rtc->class_dev, 1, tmp);

		spin_unlock_irq(&rtc_lock);

	}



	pr_debug("%s: resume, ctrl %02x\n",
@@ -594,7 +610,7 @@ static int cmos_resume(struct device *dev) 
/*----------------------------------------------------------------*/



/* The "CMOS" RTC normally lives on the platform_bus.  On ACPI systems,

 * the device node may alternatively be created as a PNP device.

 * the device node will always be created as a PNPACPI device.

 */



#ifdef	CONFIG_PNPACPI
@@ -673,7 +689,7 @@ module_exit(cmos_exit); 
/*----------------------------------------------------------------*/



/* Platform setup should have set up an RTC device, when PNPACPI is

 * unavailable ... this is the normal case, common even on PCs.

 * unavailable ... this could happen even on (older) PCs.

 */



static int __init cmos_platform_probe(struct platform_device *pdev)