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Commit c54a42b1 authored by Magnus Damm's avatar Magnus Damm Committed by Thomas Gleixner
Browse files

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: default avatarMagnus Damm <damm@opensource.se>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 17622339

include/linux/clocksource.h

+3 −0
Original line number Diff line number Diff line
@@ -154,6 +154,7 @@ extern u64 timecounter_cyc2time(struct timecounter *tc, 
 * @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 @@ struct clocksource { 
	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_unregister(struct clocksource*); 
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);

kernel/time/clocksource.c

+12 −0
Original line number Diff line number Diff line
@@ -440,6 +440,18 @@ static inline int clocksource_watchdog_kthread(void *data) { return 0; } 


#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)

 */

kernel/time/timekeeping.c

+1 −0
Original line number Diff line number Diff line
@@ -622,6 +622,7 @@ static int timekeeping_suspend(struct sys_device *dev, pm_message_t state) 
	write_sequnlock_irqrestore(&xtime_lock, flags);



	clockevents_notify(CLOCK_EVT_NOTIFY_SUSPEND, NULL);

	clocksource_suspend();



	return 0;

}