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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: David Brownell <dbrownell@users.sourceforge.net>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Brownell 2007-04-01 23:49:47 -07:00 committed by Linus Torvalds
parent a2b091dbfb
commit bcd9b89c02
1 changed files with 33 additions and 17 deletions
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50
drivers/rtc/rtc-cmos.c
View File

@ -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
@ -525,25 +539,26 @@ 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;
irqstat &= (tmp & RTC_IRQMASK) | RTC_IRQF;
if (is_intr(irqstat))
rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat);
}
spin_unlock_irq(&rtc_lock);
if (irqstat)
rtc_update_irq(&cmos->rtc->class_dev, 1, irqstat);
/* 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)