Commit 983bf125 authored by Gabriele Mazzotta's avatar Gabriele Mazzotta Committed by Alexandre Belloni
Browse files

rtc: cmos: Clear ACPI-driven alarms upon resume 

Currently ACPI-driven alarms are not cleared when they wake the
system. As consequence, expired alarms must be manually cleared to
program a new alarm. Fix this by correctly handling ACPI-driven
alarms.

More specifically, the ACPI specification [1] provides for two
alternative implementations of the RTC. Depending on the
implementation, the driver either clear the alarm from the resume
callback or from ACPI interrupt handler:

 - The platform has the RTC wakeup status fixed in hardware
   (ACPI_FADT_FIXED_RTC is 0). In this case the driver can determine
   if the RTC was the reason of the wakeup from the resume callback
   by reading the RTC status register.

 - The platform has no fixed hardware feature event bits. In this
   case a GPE is used to wake the system and the driver clears the
   alarm from its handler.

[1] http://www.acpi.info/DOWNLOADS/ACPI_5_Errata%20A.pdf



Signed-off-by: default avatarGabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
parent 97ea1906

drivers/rtc/rtc-cmos.c

+47 −0
Original line number Diff line number Diff line
@@ -899,6 +899,9 @@ static inline int cmos_poweroff(struct device *dev) 


#ifdef	CONFIG_PM_SLEEP



static void cmos_check_acpi_rtc_status(struct device *dev,

				       unsigned char *rtc_control);



static int cmos_resume(struct device *dev)

{

	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
@@ -938,6 +941,9 @@ static int cmos_resume(struct device *dev) 
			tmp &= ~RTC_AIE;

			hpet_mask_rtc_irq_bit(RTC_AIE);

		} while (mask & RTC_AIE);



		if (tmp & RTC_AIE)

			cmos_check_acpi_rtc_status(dev, &tmp);

	}

	spin_unlock_irq(&rtc_lock);
@@ -975,6 +981,20 @@ static SIMPLE_DEV_PM_OPS(cmos_pm_ops, cmos_suspend, cmos_resume); 
static u32 rtc_handler(void *context)

{

	struct device *dev = context;

	struct cmos_rtc *cmos = dev_get_drvdata(dev);

	unsigned char rtc_control = 0;

	unsigned char rtc_intr;



	spin_lock_irq(&rtc_lock);

	if (cmos_rtc.suspend_ctrl)

		rtc_control = CMOS_READ(RTC_CONTROL);

	if (rtc_control & RTC_AIE) {

		cmos_rtc.suspend_ctrl &= ~RTC_AIE;

		CMOS_WRITE(rtc_control, RTC_CONTROL);

		rtc_intr = CMOS_READ(RTC_INTR_FLAGS);

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

	}

	spin_unlock_irq(&rtc_lock);



	pm_wakeup_event(dev, 0);

	acpi_clear_event(ACPI_EVENT_RTC);
@@ -1041,12 +1061,39 @@ static void cmos_wake_setup(struct device *dev) 
	device_init_wakeup(dev, 1);

}



static void cmos_check_acpi_rtc_status(struct device *dev,

				       unsigned char *rtc_control)

{

	struct cmos_rtc *cmos = dev_get_drvdata(dev);

	acpi_event_status rtc_status;

	acpi_status status;



	if (acpi_gbl_FADT.flags & ACPI_FADT_FIXED_RTC)

		return;



	status = acpi_get_event_status(ACPI_EVENT_RTC, &rtc_status);

	if (ACPI_FAILURE(status)) {

		dev_err(dev, "Could not get RTC status\n");

	} else if (rtc_status & ACPI_EVENT_FLAG_SET) {

		unsigned char mask;

		*rtc_control &= ~RTC_AIE;

		CMOS_WRITE(*rtc_control, RTC_CONTROL);

		mask = CMOS_READ(RTC_INTR_FLAGS);

		rtc_update_irq(cmos->rtc, 1, mask);

	}

}



#else



static void cmos_wake_setup(struct device *dev)

{

}



static void cmos_check_acpi_rtc_status(struct device *dev,

				       unsigned char *rtc_control)

{

}



#endif



#ifdef	CONFIG_PNP

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