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[patch 39/66] clocksource/dummy_timer: Convert to hotplug state machine

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

Signed-off-by: Richard Cochran <rcochran@linutronix.de>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
 drivers/clocksource/dummy_timer.c |   36 ++++++------------------------------
 include/linux/cpuhotplug.h        |    1 +
 2 files changed, 7 insertions(+), 30 deletions(-)

--- a/drivers/clocksource/dummy_timer.c
+++ b/drivers/clocksource/dummy_timer.c
@@ -16,10 +16,9 @@
 
 static DEFINE_PER_CPU(struct clock_event_device, dummy_timer_evt);
 
-static void dummy_timer_setup(void)
+static int dummy_timer_starting_cpu(unsigned int cpu)
 {
-	int cpu = smp_processor_id();
-	struct clock_event_device *evt = raw_cpu_ptr(&dummy_timer_evt);
+	struct clock_event_device *evt = per_cpu_ptr(&dummy_timer_evt, cpu);
 
 	evt->name	= "dummy_timer";
 	evt->features	= CLOCK_EVT_FEAT_PERIODIC |
@@ -29,36 +28,13 @@ static void dummy_timer_setup(void)
 	evt->cpumask	= cpumask_of(cpu);
 
 	clockevents_register_device(evt);
+	return 0;
 }
 
-static int dummy_timer_cpu_notify(struct notifier_block *self,
-				      unsigned long action, void *hcpu)
-{
-	if ((action & ~CPU_TASKS_FROZEN) == CPU_STARTING)
-		dummy_timer_setup();
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block dummy_timer_cpu_nb = {
-	.notifier_call = dummy_timer_cpu_notify,
-};
-
 static int __init dummy_timer_register(void)
 {
-	int err = 0;
-
-	cpu_notifier_register_begin();
-	err = __register_cpu_notifier(&dummy_timer_cpu_nb);
-	if (err)
-		goto out;
-
-	/* We won't get a call on the boot CPU, so register immediately */
-	if (num_possible_cpus() > 1)
-		dummy_timer_setup();
-
-out:
-	cpu_notifier_register_done();
-	return err;
+	return cpuhp_setup_state(CPUHP_AP_DUMMY_TIMER_STARTING,
+				 "AP_DUMMY_TIMER_STARTING",
+				 dummy_timer_starting_cpu, NULL);
 }
 early_initcall(dummy_timer_register);
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -39,6 +39,7 @@ enum cpuhp_state {
 	CPUHP_AP_PERF_ARM_STARTING,
 	CPUHP_AP_ARM_ARCH_TIMER_STARTING,
 	CPUHP_AP_ARM_GLOBAL_TIMER_STARTING,
+	CPUHP_AP_DUMMY_TIMER_STARTING,
 	CPUHP_AP_KVM_STARTING,
 	CPUHP_AP_NOTIFY_STARTING,
 	CPUHP_AP_ONLINE,

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[patch 00/66] cpuhotplug: Convert all priority notifiers to the state  machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 29/66] powerpc: numa: Convert to hotplug state machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 27/66] workqueue: Convert to state machine callbacks Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
    Re: [patch 27/66] workqueue: Convert to state machine callbacks Ingo Molnar <mingo@kernel.org> - 2016-07-11 16:40 +0200
      Re: [patch 27/66] workqueue: Convert to state machine callbacks Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 17:00 +0200
    Re: [patch 27/66] workqueue: Convert to state machine callbacks Tejun Heo <tj@kernel.org> - 2016-07-12 16:40 +0200
  [patch 37/66] clocksource/arm_arch_timer: Convert to hotplug state  machine. Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 39/66] clocksource/dummy_timer: Convert to hotplug state  machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 32/66] x86/apb_timer: Convert to hotplug state machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 20/66] sh: perf: Convert the hotplug notifiers to state  machine callbacks Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 16/66] blackfin: perf: Convert hotplug notifier to state  machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 11/66] perf/x86/amd/uncore: Convert to hotplug state machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 14/66] perf/x86/intel/cqm: Convert Intel CQM to hotplug state  machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
  [patch 01/66] x86/vdso: Convert to hotplug state machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200
    Re: [patch 01/66] x86/vdso: Convert to hotplug state machine Andy Lutomirski <luto@amacapital.net> - 2016-07-11 21:00 +0200
  [patch 08/66] perf: Convert to hotplug state machine Anna-Maria Gleixner <anna-maria@linutronix.de> - 2016-07-11 14:50 +0200

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