diff mbox

[06/41] clocksource: exynos_mct: Migrate to new 'set-state' interface

Message ID a1d7ad942bfc08b91b7ae0d9ba3b19b579f469c9.1434622147.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar June 18, 2015, 10:54 a.m. UTC 
Migrate exynos_mct driver to the new 'set-state' interface provided by
clockevents core, the earlier 'set-mode' interface is marked obsolete
now.

This also enables us to implement callbacks for new states of clockevent
devices, for example: ONESHOT_STOPPED.

Cc: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/clocksource/exynos_mct.c | 85 +++++++++++++++++++---------------------
 1 file changed, 40 insertions(+), 45 deletions(-)

Comments

Viresh Kumar June 19, 2015, 2:14 a.m. UTC | #1 
Hi Alexey,

On 18-06-15, 19:38, Alexey Klimov wrote:
> (adding samsung list and Krzysztof to c/c)

Thanks.

> Please don't forget to send patches to platform list and platform maintainers.

Hmmm, I cc'd Kukjin on this patch as he was the one Acking most of the
patches on this driver recently (had a look at git log). Also looked
at MAINTAINERS and the driver itself to look for maintainers, and
kukjin was all I can find. Yes, get_maintainers gave the two names you
added, but many a times it generates list longer than required and so
I don't completely depend on that.

Anyway, thanks.

> On Thu, Jun 18, 2015 at 1:54 PM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> > +static int set_state_shutdown(struct clock_event_device *evt)
> > +{
> > +       exynos4_mct_tick_stop(this_cpu_ptr(&percpu_mct_tick));

Let me clarify the purpose of this patch and the series.

Its only about breaking the older ->set_mode() callback into state
based callbacks and not change the way things were done. And so no
improvements in this patch. If there are improvements possible on the
driver, then they must be done separately.

> Passed evt pointer isn't used

Its a callback from clockevents core, and we can't get rid of the
argument. :)

> and instead you're going to locate
> percpu_mct_tick struct knowing current cpu number offset.

That's the way ->set_mode() was doing it and so I didn't touched it to
keep this patch simple.

> What do you think, since evt is embedded into percpu_mct_tick
> structure then maybe it will be cheaper to calculate percpu_mct_tick
> using container_of()?
> 
> struct mct_clock_event_device *mevt;
> mevt = container_of(evt, struct mct_clock_event_device, evt);

Ofcourse, but that has to be fixed for many routines and should be
done in a separate patch. It doesn't belong to this one.
 
> > @@ -455,7 +447,10 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt)
> >         evt->name = mevt->name;
> >         evt->cpumask = cpumask_of(cpu);
> >         evt->set_next_event = exynos4_tick_set_next_event;
> > -       evt->set_mode = exynos4_tick_set_mode;
> > +       evt->set_state_periodic = set_state_periodic;
> > +       evt->set_state_shutdown = set_state_shutdown;
> > +       evt->set_state_oneshot = set_state_shutdown;
> > +       evt->tick_resume = set_state_shutdown;
> 
> Do i correctly understand that during massive hot-plug cpu events (i
> guess that will lead to CPU_STARING notification) on power management
> this *_timer_setup() function will be called?

I hope so.

> And here code performs setting of rather constant values and copying.
> You're going to increase number of such strange assignments.
> 
> Well, just lazy-thinking. Can we do something like this:
> 
> for_each_possible_cpu(cpu) {
>           exynos4_local_timer_setup_prepare(&per_cpu(percpu_mct_tick,
> cpu).evt, cpu);
> }
> 
> somewhere in exynos_mct init functions and assign most of these values
> for each evt structure?
> And make *_timer_setup() function lighter moving some code to
> prepare/init functions.

I agree.. But again, that has to be done in a separate patch.

> If it makes any sense i can take a look and try to prepare patch.

Sure..

> Do you need testers? I can test it on odroid-xu3.

That will be good.

> Can't find in emails similar patch for ARM arch timer. Any plans about
> it? Or if it's already converted to 'set-state' then could you please
> share a link?

https://git.linaro.org/people/daniel.lezcano/linux.git/shortlog/refs/heads/clockevents/4.3
diff mbox

Patch

diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c
index 935b05936dbd..82e060cb7b95 100644
--- a/drivers/clocksource/exynos_mct.c
+++ b/drivers/clocksource/exynos_mct.c
@@ -257,15 +257,14 @@  static void exynos4_mct_comp0_stop(void)
 	exynos4_mct_write(0, EXYNOS4_MCT_G_INT_ENB);
 }
 
-static void exynos4_mct_comp0_start(enum clock_event_mode mode,
-				    unsigned long cycles)
+static void exynos4_mct_comp0_start(bool periodic, unsigned long cycles)
 {
 	unsigned int tcon;
 	cycle_t comp_cycle;
 
 	tcon = readl_relaxed(reg_base + EXYNOS4_MCT_G_TCON);
 
-	if (mode == CLOCK_EVT_MODE_PERIODIC) {
+	if (periodic) {
 		tcon |= MCT_G_TCON_COMP0_AUTO_INC;
 		exynos4_mct_write(cycles, EXYNOS4_MCT_G_COMP0_ADD_INCR);
 	}
@@ -283,38 +282,38 @@  static void exynos4_mct_comp0_start(enum clock_event_mode mode,
 static int exynos4_comp_set_next_event(unsigned long cycles,
 				       struct clock_event_device *evt)
 {
-	exynos4_mct_comp0_start(evt->mode, cycles);
+	exynos4_mct_comp0_start(false, cycles);
 
 	return 0;
 }
 
-static void exynos4_comp_set_mode(enum clock_event_mode mode,
-				  struct clock_event_device *evt)
+static int mct_set_state_shutdown(struct clock_event_device *evt)
 {
-	unsigned long cycles_per_jiffy;
 	exynos4_mct_comp0_stop();
+	return 0;
+}
 
-	switch (mode) {
-	case CLOCK_EVT_MODE_PERIODIC:
-		cycles_per_jiffy =
-			(((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
-		exynos4_mct_comp0_start(mode, cycles_per_jiffy);
-		break;
+static int mct_set_state_periodic(struct clock_event_device *evt)
+{
+	unsigned long cycles_per_jiffy;
 
-	case CLOCK_EVT_MODE_ONESHOT:
-	case CLOCK_EVT_MODE_UNUSED:
-	case CLOCK_EVT_MODE_SHUTDOWN:
-	case CLOCK_EVT_MODE_RESUME:
-		break;
-	}
+	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
+			    >> evt->shift);
+	exynos4_mct_comp0_stop();
+	exynos4_mct_comp0_start(true, cycles_per_jiffy);
+	return 0;
 }
 
 static struct clock_event_device mct_comp_device = {
-	.name		= "mct-comp",
-	.features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
-	.rating		= 250,
-	.set_next_event	= exynos4_comp_set_next_event,
-	.set_mode	= exynos4_comp_set_mode,
+	.name			= "mct-comp",
+	.features		= CLOCK_EVT_FEAT_PERIODIC |
+				  CLOCK_EVT_FEAT_ONESHOT,
+	.rating			= 250,
+	.set_next_event		= exynos4_comp_set_next_event,
+	.set_state_periodic	= mct_set_state_periodic,
+	.set_state_shutdown	= mct_set_state_shutdown,
+	.set_state_oneshot	= mct_set_state_shutdown,
+	.tick_resume		= mct_set_state_shutdown,
 };
 
 static irqreturn_t exynos4_mct_comp_isr(int irq, void *dev_id)
@@ -390,39 +389,32 @@  static int exynos4_tick_set_next_event(unsigned long cycles,
 	return 0;
 }
 
-static inline void exynos4_tick_set_mode(enum clock_event_mode mode,
-					 struct clock_event_device *evt)
+static int set_state_shutdown(struct clock_event_device *evt)
+{
+	exynos4_mct_tick_stop(this_cpu_ptr(&percpu_mct_tick));
+	return 0;
+}
+
+static int set_state_periodic(struct clock_event_device *evt)
 {
 	struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);
 	unsigned long cycles_per_jiffy;
 
+	cycles_per_jiffy = (((unsigned long long)NSEC_PER_SEC / HZ * evt->mult)
+			    >> evt->shift);
 	exynos4_mct_tick_stop(mevt);
-
-	switch (mode) {
-	case CLOCK_EVT_MODE_PERIODIC:
-		cycles_per_jiffy =
-			(((unsigned long long) NSEC_PER_SEC / HZ * evt->mult) >> evt->shift);
-		exynos4_mct_tick_start(cycles_per_jiffy, mevt);
-		break;
-
-	case CLOCK_EVT_MODE_ONESHOT:
-	case CLOCK_EVT_MODE_UNUSED:
-	case CLOCK_EVT_MODE_SHUTDOWN:
-	case CLOCK_EVT_MODE_RESUME:
-		break;
-	}
+	exynos4_mct_tick_start(cycles_per_jiffy, mevt);
+	return 0;
 }
 
 static void exynos4_mct_tick_clear(struct mct_clock_event_device *mevt)
 {
-	struct clock_event_device *evt = &mevt->evt;
-
 	/*
 	 * This is for supporting oneshot mode.
 	 * Mct would generate interrupt periodically
 	 * without explicit stopping.
 	 */
-	if (evt->mode != CLOCK_EVT_MODE_PERIODIC)
+	if (!clockevent_state_periodic(&mevt->evt))
 		exynos4_mct_tick_stop(mevt);
 
 	/* Clear the MCT tick interrupt */
@@ -455,7 +447,10 @@  static int exynos4_local_timer_setup(struct clock_event_device *evt)
 	evt->name = mevt->name;
 	evt->cpumask = cpumask_of(cpu);
 	evt->set_next_event = exynos4_tick_set_next_event;
-	evt->set_mode = exynos4_tick_set_mode;
+	evt->set_state_periodic = set_state_periodic;
+	evt->set_state_shutdown = set_state_shutdown;
+	evt->set_state_oneshot = set_state_shutdown;
+	evt->tick_resume = set_state_shutdown;
 	evt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
 	evt->rating = 450;
 
@@ -482,7 +477,7 @@  static int exynos4_local_timer_setup(struct clock_event_device *evt)
 
 static void exynos4_local_timer_stop(struct clock_event_device *evt)
 {
-	evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt);
+	evt->set_state_shutdown(evt);
 	if (mct_int_type == MCT_INT_SPI)
 		free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick));
 	else