Merge tag 'rtc-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

Pull RTC updates from Alexandre Belloni:
 "This cycle, we have a new RTC driver, for the SpacemiT P1. The optee
  driver gets alarm support. We also get a fix for a race condition that
  was fairly rare unless while stress testing the alarms.

  Subsystem:
   - Fix race when setting alarm
   - Ensure alarm irq is enabled when UIE is enabled
   - remove unneeded 'fast_io' parameter in regmap_config

  New driver:
   - SpacemiT P1 RTC

  Drivers:
   - efi: Remove wakeup functionality
   - optee: add alarms support
   - s3c: Drop support for S3C2410
   - zynqmp: Restore alarm functionality after kexec transition"

* tag 'rtc-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux: (29 commits)
  rtc: interface: Ensure alarm irq is enabled when UIE is enabled
  rtc: tps6586x: Fix initial enable_irq/disable_irq balance
  rtc: cpcap: Fix initial enable_irq/disable_irq balance
  rtc: isl12022: Fix initial enable_irq/disable_irq balance
  rtc: interface: Fix long-standing race when setting alarm
  rtc: pcf2127: fix watchdog interrupt mask on pcf2131
  rtc: zynqmp: Restore alarm functionality after kexec transition
  rtc: amlogic-a4: Optimize global variables
  rtc: sd2405al: Add I2C address.
  rtc: Kconfig: move symbols to proper section
  rtc: optee: make optee_rtc_pm_ops static
  rtc: optee: Fix error code in optee_rtc_read_alarm()
  rtc: optee: fix error code in probe()
  dt-bindings: rtc: Convert apm,xgene-rtc to DT schema
  rtc: spacemit: support the SpacemiT P1 RTC
  rtc: optee: add alarm related rtc ops to optee rtc driver
  rtc: optee: remove unnecessary memory operations
  rtc: optee: fix memory leak on driver removal
  rtc: x1205: Fix Xicor X1205 vendor prefix
  dt-bindings: rtc: Fix Xicor X1205 vendor prefix
  ...

1 files changed, 27 insertions, 0 deletions

diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c
index dc741ba29fa3..b8b298efd9a9 100644
--- a/drivers/rtc/interface.c
+++ b/drivers/rtc/interface.c
@@ -443,6 +443,29 @@ static int __rtc_set_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm)
 	else
 		err = rtc->ops->set_alarm(rtc->dev.parent, alarm);
 
+	/*
+	 * Check for potential race described above. If the waiting for next
+	 * second, and the second just ticked since the check above, either
+	 *
+	 * 1) It ticked after the alarm was set, and an alarm irq should be
+	 *    generated.
+	 *
+	 * 2) It ticked before the alarm was set, and alarm irq most likely will
+	 * not be generated.
+	 *
+	 * While we cannot easily check for which of these two scenarios we
+	 * are in, we can return -ETIME to signal that the timer has already
+	 * expired, which is true in both cases.
+	 */
+	if ((scheduled - now) <= 1) {
+		err = __rtc_read_time(rtc, &tm);
+		if (err)
+			return err;
+		now = rtc_tm_to_time64(&tm);
+		if (scheduled <= now)
+			return -ETIME;
+	}
+
 	trace_rtc_set_alarm(rtc_tm_to_time64(&alarm->time), err);
 	return err;
 }
@@ -594,6 +617,10 @@ int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled)
 		rtc->uie_rtctimer.node.expires = ktime_add(now, onesec);
 		rtc->uie_rtctimer.period = ktime_set(1, 0);
 		err = rtc_timer_enqueue(rtc, &rtc->uie_rtctimer);
+		if (!err && rtc->ops && rtc->ops->alarm_irq_enable)
+			err = rtc->ops->alarm_irq_enable(rtc->dev.parent, 1);
+		if (err)
+			goto out;
 	} else {
 		rtc_timer_remove(rtc, &rtc->uie_rtctimer);
 	}