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rtc: cmos: Clear ACPI-driven alarms upon resume

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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: Gabriele Mazzotta <gabriele.mzt@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Gabriele Mazzotta 2016-09-20 01:12:43 +02:00 committed by Alexandre Belloni
parent 97ea1906b3
commit 983bf1256e
1 changed files with 47 additions and 0 deletions
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47
drivers/rtc/rtc-cmos.c
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@ -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