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drivers/rtc/rtc-cmos.c: work around bios clearing rtc control

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The bios may clear the rtc control register when resuming the system. Since the
cmos interrupt handler may now be run before the rtc_cmos is resumed, this can
cause the interrupt handler to ignore an alarm since the alarm bit is not set in
the rtc control register. To work around this, check if the rtc_cmos is
suspended and use the stored value for the rtc control register.

Signed-off-by: Derek Basehore <dbasehore@chromium.org>
Reviewed-by: Sameer Nanda <snanda@chromium.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Jingoo Han <jg1.han@samsung.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Derek Basehore 2013-07-03 15:07:54 -07:00 committed by Linus Torvalds
parent ae8458949a
commit 998a06051a
1 changed files with 22 additions and 13 deletions
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23
drivers/rtc/rtc-cmos.c
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@ -556,17 +556,24 @@ static irqreturn_t cmos_interrupt(int irq, void *p)
rtc_control = CMOS_READ(RTC_CONTROL);
if (is_hpet_enabled())
irqstat = (unsigned long)irq & 0xF0;
/* If we were suspended, RTC_CONTROL may not be accurate since the
* bios may have cleared it.
*/
if (!cmos_rtc.suspend_ctrl)
irqstat &= (rtc_control & RTC_IRQMASK) | RTC_IRQF;
else
irqstat &= (cmos_rtc.suspend_ctrl & RTC_IRQMASK) | RTC_IRQF;
/* All Linux RTC alarms should be treated as if they were oneshot.
* Similar code may be needed in system wakeup paths, in case the
* alarm woke the system.
*/
if (irqstat & RTC_AIE) {
cmos_rtc.suspend_ctrl &= ~RTC_AIE;
rtc_control &= ~RTC_AIE;
CMOS_WRITE(rtc_control, RTC_CONTROL);
hpet_mask_rtc_irq_bit(RTC_AIE);
CMOS_READ(RTC_INTR_FLAGS);
}
spin_unlock(&rtc_lock);
@ -839,11 +846,7 @@ static inline int cmos_poweroff(struct device *dev)
static int cmos_resume(struct device *dev)
{
struct cmos_rtc *cmos = dev_get_drvdata(dev);
unsigned char tmp = cmos->suspend_ctrl;
/* re-enable any irqs previously active */
if (tmp & RTC_IRQMASK) {
unsigned char mask;
unsigned char tmp;
if (cmos->enabled_wake) {
if (cmos->wake_off)
@ -854,6 +857,12 @@ static int cmos_resume(struct device *dev)
}
spin_lock_irq(&rtc_lock);
tmp = cmos->suspend_ctrl;
cmos->suspend_ctrl = 0;
/* re-enable any irqs previously active */
if (tmp & RTC_IRQMASK) {
unsigned char mask;
if (device_may_wakeup(dev))
hpet_rtc_timer_init();
@ -873,8 +882,8 @@ static int cmos_resume(struct device *dev)
tmp &= ~RTC_AIE;
hpet_mask_rtc_irq_bit(RTC_AIE);
} while (mask & RTC_AIE);
spin_unlock_irq(&rtc_lock);
}
spin_unlock_irq(&rtc_lock);
dev_dbg(dev, "resume, ctrl %02x\n", tmp);