clocksource: add suspend callback
Add a clocksource suspend callback. This callback can be used by the
clocksource driver to shutdown and perform any kind of late suspend
activities even though the clocksource driver itself is a non-sysdev
driver.
One example where this is useful is to fix the sh_cmt.c platform driver
that today suspends using the platform bus and shuts down the clocksource
too early.
With this callback in place the sh_cmt driver will suspend using the
clocksource and clockevent hooks and leave the platform device pm
callbacks unused.
Signed-off-by: Magnus Damm <damm@opensource.se>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 0de7e72..4bca8b6 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -154,6 +154,7 @@
* @max_idle_ns: max idle time permitted by the clocksource (nsecs)
* @flags: flags describing special properties
* @vread: vsyscall based read
+ * @suspend: suspend function for the clocksource, if necessary
* @resume: resume function for the clocksource, if necessary
*/
struct clocksource {
@@ -172,6 +173,7 @@
u64 max_idle_ns;
unsigned long flags;
cycle_t (*vread)(void);
+ void (*suspend)(struct clocksource *cs);
void (*resume)(struct clocksource *cs);
#ifdef CONFIG_IA64
void *fsys_mmio; /* used by fsyscall asm code */
@@ -277,6 +279,7 @@
extern void clocksource_touch_watchdog(void);
extern struct clocksource* clocksource_get_next(void);
extern void clocksource_change_rating(struct clocksource *cs, int rating);
+extern void clocksource_suspend(void);
extern void clocksource_resume(void);
extern struct clocksource * __init __weak clocksource_default_clock(void);
extern void clocksource_mark_unstable(struct clocksource *cs);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 08adacb..bd24666 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -441,6 +441,18 @@
#endif /* CONFIG_CLOCKSOURCE_WATCHDOG */
/**
+ * clocksource_suspend - suspend the clocksource(s)
+ */
+void clocksource_suspend(void)
+{
+ struct clocksource *cs;
+
+ list_for_each_entry_reverse(cs, &clocksource_list, list)
+ if (cs->suspend)
+ cs->suspend(cs);
+}
+
+/**
* clocksource_resume - resume the clocksource(s)
*/
void clocksource_resume(void)
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 7faaa32..843d8a7 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -622,6 +622,7 @@
write_sequnlock_irqrestore(&xtime_lock, flags);
clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);
+ clocksource_suspend();
return 0;
}
