clockevents: Handle tick device's resume separately

Upcoming patch will redefine possible states of a clockevent
device. The RESUME mode is a special case only for tick's
clockevent devices. In future it can be replaced by ->resume()
callback already available for clockevent devices.

Lets handle it separately so that clockevents_set_mode() only
handles states valid across all devices. This also renames
set_mode_resume() to tick_resume() to make it more explicit.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: linaro-kernel@lists.linaro.org
Cc: linaro-networking@linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/c1b0112410870f49e7bf06958e1483eac6c15e20.1425037853.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/clockchips.h

@@ -87,7 +87,7 @@ enum clock_event_mode {
  * @set_mode_periodic:	switch mode to periodic, if !set_mode
  * @set_mode_oneshot:	switch mode to oneshot, if !set_mode
  * @set_mode_shutdown:	switch mode to shutdown, if !set_mode
- * @set_mode_resume:	resume clkevt device, if !set_mode
+ * @tick_resume:	resume clkevt device, if !set_mode
  * @broadcast:		function to broadcast events
  * @min_delta_ticks:	minimum delta value in ticks stored for reconfiguration
  * @max_delta_ticks:	maximum delta value in ticks stored for reconfiguration
@@ -125,7 +125,7 @@ struct clock_event_device {
 	int			(*set_mode_periodic)(struct clock_event_device *);
 	int			(*set_mode_oneshot)(struct clock_event_device *);
 	int			(*set_mode_shutdown)(struct clock_event_device *);
-	int			(*set_mode_resume)(struct clock_event_device *);
+	int			(*tick_resume)(struct clock_event_device *);
 
 	void			(*broadcast)(const struct cpumask *mask);
 	void			(*suspend)(struct clock_event_device *);

kernel/time/clockevents.c

@@ -100,7 +100,7 @@ static int __clockevents_set_mode(struct clock_event_device *dev,
 	/* Transition with legacy set_mode() callback */
 	if (dev->set_mode) {
 		/* Legacy callback doesn't support new modes */
-		if (mode > CLOCK_EVT_MODE_RESUME)
+		if (mode > CLOCK_EVT_MODE_ONESHOT)
 			return -ENOSYS;
 		dev->set_mode(mode, dev);
 		return 0;
@@ -133,13 +133,6 @@ static int __clockevents_set_mode(struct clock_event_device *dev,
 			return -ENOSYS;
 		return dev->set_mode_oneshot(dev);
 
-	case CLOCK_EVT_MODE_RESUME:
-		/* Optional callback */
-		if (dev->set_mode_resume)
-			return dev->set_mode_resume(dev);
-		else
-			return 0;
-
 	default:
 		return -ENOSYS;
 	}
@@ -184,6 +177,25 @@ void clockevents_shutdown(struct clock_event_device *dev)
 	dev->next_event.tv64 = KTIME_MAX;
 }
 
+/**
+ * clockevents_tick_resume -	Resume the tick device before using it again
+ * @dev:			device to resume
+ */
+int clockevents_tick_resume(struct clock_event_device *dev)
+{
+	int ret = 0;
+
+	if (dev->set_mode)
+		dev->set_mode(CLOCK_EVT_MODE_RESUME, dev);
+	else if (dev->tick_resume)
+		ret = dev->tick_resume(dev);
+
+	if (likely(!ret))
+		dev->mode = CLOCK_EVT_MODE_RESUME;
+
+	return ret;
+}
+
 #ifdef CONFIG_GENERIC_CLOCKEVENTS_MIN_ADJUST
 
 /* Limit min_delta to a jiffie */
@@ -433,7 +445,7 @@ static int clockevents_sanity_check(struct clock_event_device *dev)
 	if (dev->set_mode) {
 		/* We shouldn't be supporting new modes now */
 		WARN_ON(dev->set_mode_periodic || dev->set_mode_oneshot ||
-			dev->set_mode_shutdown || dev->set_mode_resume);
+			dev->set_mode_shutdown || dev->tick_resume);
 		return 0;
 	}
 

kernel/time/tick-broadcast.c

@@ -464,7 +464,7 @@ int tick_resume_broadcast(void)
 	bc = tick_broadcast_device.evtdev;
 
 	if (bc) {
-		clockevents_set_mode(bc, CLOCK_EVT_MODE_RESUME);
+		clockevents_tick_resume(bc);
 
 		switch (tick_broadcast_device.mode) {
 		case TICKDEV_MODE_PERIODIC:

kernel/time/tick-common.c

@@ -384,7 +384,7 @@ void tick_resume(void)
 	struct tick_device *td = this_cpu_ptr(&tick_cpu_device);
 	int broadcast = tick_resume_broadcast();
 
-	clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_RESUME);
+	clockevents_tick_resume(td->evtdev);
 
 	if (!broadcast) {
 		if (td->mode == TICKDEV_MODE_PERIODIC)

kernel/time/tick-internal.h

@@ -32,6 +32,7 @@ extern bool tick_check_replacement(struct clock_event_device *curdev,
 extern void tick_install_replacement(struct clock_event_device *dev);
 
 extern void clockevents_shutdown(struct clock_event_device *dev);
+extern int clockevents_tick_resume(struct clock_event_device *dev);
 
 extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt);
 

kernel/time/timer_list.c

@@ -251,9 +251,9 @@ print_tickdevice(struct seq_file *m, struct tick_device *td, int cpu)
 			SEQ_printf(m, "\n");
 		}
 
-		if (dev->set_mode_resume) {
+		if (dev->tick_resume) {
 			SEQ_printf(m, " resume:   ");
-			print_name_offset(m, dev->set_mode_resume);
+			print_name_offset(m, dev->tick_resume);
 			SEQ_printf(m, "\n");
 		}
 	}