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Commit d11b3a60 authored by Richard Cochran's avatar Richard Cochran Committed by Ingo Molnar
Browse files

clocksource/exynos_mct: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: default avatarRichard Cochran <rcochran@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-samsung-soc@vger.kernel.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153338.147940411@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent b8a12296

drivers/clocksource/exynos_mct.c

+12 −34
Original line number Diff line number Diff line
@@ -443,10 +443,11 @@ static irqreturn_t exynos4_mct_tick_isr(int irq, void *dev_id) 
	return IRQ_HANDLED;

}



static int exynos4_local_timer_setup(struct mct_clock_event_device *mevt)

static int exynos4_mct_starting_cpu(unsigned int cpu)

{

	struct mct_clock_event_device *mevt =

		per_cpu_ptr(&percpu_mct_tick, cpu);

	struct clock_event_device *evt = &mevt->evt;

	unsigned int cpu = smp_processor_id();



	mevt->base = EXYNOS4_MCT_L_BASE(cpu);

	snprintf(mevt->name, sizeof(mevt->name), "mct_tick%d", cpu);
@@ -480,8 +481,10 @@ static int exynos4_local_timer_setup(struct mct_clock_event_device *mevt) 
	return 0;

}



static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt)

static int exynos4_mct_dying_cpu(unsigned int cpu)

{

	struct mct_clock_event_device *mevt =

		per_cpu_ptr(&percpu_mct_tick, cpu);

	struct clock_event_device *evt = &mevt->evt;



	evt->set_state_shutdown(evt);
@@ -491,39 +494,12 @@ static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt) 
	} else {

		disable_percpu_irq(mct_irqs[MCT_L0_IRQ]);

	}

	return 0;

}



static int exynos4_mct_cpu_notify(struct notifier_block *self,

					   unsigned long action, void *hcpu)

{

	struct mct_clock_event_device *mevt;



	/*

	 * Grab cpu pointer in each case to avoid spurious

	 * preemptible warnings

	 */

	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_STARTING:

		mevt = this_cpu_ptr(&percpu_mct_tick);

		exynos4_local_timer_setup(mevt);

		break;

	case CPU_DYING:

		mevt = this_cpu_ptr(&percpu_mct_tick);

		exynos4_local_timer_stop(mevt);

		break;

	}



	return NOTIFY_OK;

}



static struct notifier_block exynos4_mct_cpu_nb = {

	.notifier_call = exynos4_mct_cpu_notify,

};



static int __init exynos4_timer_resources(struct device_node *np, void __iomem *base)

{

	int err, cpu;

	struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick);

	struct clk *mct_clk, *tick_clk;



	tick_clk = np ? of_clk_get_by_name(np, "fin_pll") :
@@ -570,12 +546,14 @@ static int __init exynos4_timer_resources(struct device_node *np, void __iomem * 
		}

	}



	err = register_cpu_notifier(&exynos4_mct_cpu_nb);

	/* Install hotplug callbacks which configure the timer on this CPU */

	err = cpuhp_setup_state(CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,

				"AP_EXYNOS4_MCT_TIMER_STARTING",

				exynos4_mct_starting_cpu,

				exynos4_mct_dying_cpu);

	if (err)

		goto out_irq;



	/* Immediately configure the timer on the boot CPU */

	exynos4_local_timer_setup(mevt);

	return 0;



out_irq:

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ enum cpuhp_state { 
	CPUHP_AP_ARM_ARCH_TIMER_STARTING,

	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,

	CPUHP_AP_DUMMY_TIMER_STARTING,

	CPUHP_AP_EXYNOS4_MCT_TIMER_STARTING,

	CPUHP_AP_ARM_TWD_STARTING,

	CPUHP_AP_METAG_TIMER_STARTING,

	CPUHP_AP_QCOM_TIMER_STARTING,