timekeeping: Add suspend and resume of clock event devices

Some clock event devices, for example such that belong to PM domains,
need to be handled in a spcial way during the timekeeping suspend
and resume (which takes place in the system core, or "syscore",
stages of system power transitions) in analogy with clock sources.

Introduce .suspend() and .resume() callbacks for clock event devices
that will be executed by timekeeping_suspend/_resume(), respectively,
next the the clock sources' .suspend() and .resume() callbacks.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/include/linux/clockchips.h b/include/linux/clockchips.h
index acba894374a1537b4b961eee222e9c28b53845cf..8a7096fcb01ee1354e1d46c67d5d1ff9919bc742 100644 (file)
--- a/include/linux/clockchips.h
+++ b/include/linux/clockchips.h
@@ -97,6 +97,8 @@ struct clock_event_device {
        void                    (*broadcast)(const struct cpumask *mask);
        void                    (*set_mode)(enum clock_event_mode mode,
                                            struct clock_event_device *);
+       void                    (*suspend)(struct clock_event_device *);
+       void                    (*resume)(struct clock_event_device *);
        unsigned long           min_delta_ticks;
        unsigned long           max_delta_ticks;
 
@@ -156,6 +158,9 @@ clockevents_calc_mult_shift(struct clock_event_device *ce, u32 freq, u32 minsec)
                                      freq, minsec);
 }
 
+extern void clockevents_suspend(void);
+extern void clockevents_resume(void);
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 extern void clockevents_notify(unsigned long reason, void *arg);
 #else
@@ -164,6 +169,9 @@ extern void clockevents_notify(unsigned long reason, void *arg);
 
 #else /* CONFIG_GENERIC_CLOCKEVENTS_BUILD */
 
+static inline void clockevents_suspend(void) {}
+static inline void clockevents_resume(void) {}
+
 #define clockevents_notify(reason, arg) do { } while (0)
 
 #endif

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 7e1ce012a851351c10853fe732e714afa2bb8a5c..30b6de0d977c4734eb479d7489f61e56b35afaa8 100644 (file)
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -397,6 +397,30 @@ void clockevents_exchange_device(struct clock_event_device *old,
        local_irq_restore(flags);
 }
 
+/**
+ * clockevents_suspend - suspend clock devices
+ */
+void clockevents_suspend(void)
+{
+       struct clock_event_device *dev;
+
+       list_for_each_entry_reverse(dev, &clockevent_devices, list)
+               if (dev->suspend)
+                       dev->suspend(dev);
+}
+
+/**
+ * clockevents_resume - resume clock devices
+ */
+void clockevents_resume(void)
+{
+       struct clock_event_device *dev;
+
+       list_for_each_entry(dev, &clockevent_devices, list)
+               if (dev->resume)
+                       dev->resume(dev);
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS
 /**
  * clockevents_notify - notification about relevant events

diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 34e5eac81424d98738246415a85d1a98a042bef1..312a675cb240e4d607bfb24081bcc17ed0308230 100644 (file)
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -773,6 +773,7 @@ static void timekeeping_resume(void)
 
        read_persistent_clock(&ts);
 
+       clockevents_resume();
        clocksource_resume();
 
        write_seqlock_irqsave(&tk->lock, flags);
@@ -832,6 +833,7 @@ static int timekeeping_suspend(void)
 
        clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
        clocksource_suspend();
+       clockevents_suspend();
 
        return 0;
 }