[tip:smp/hotplug] ARC/time: Convert to hotplug state machine

From: tip-bot for Anna-Maria Gleixner
Date: Tue Jul 19 2016 - 03:33:13 EST


Commit-ID: ecd8081f6fb9032c41e5c38885f06836da6ab455
Gitweb: http://git.kernel.org/tip/ecd8081f6fb9032c41e5c38885f06836da6ab455
Author: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
AuthorDate: Wed, 13 Jul 2016 17:17:07 +0000
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 15 Jul 2016 10:41:46 +0200

ARC/time: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Anna-Maria Gleixner <anna-maria@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx
Cc: rt@xxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20160713153338.391826254@xxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/arc/kernel/time.c | 48 +++++++++++++++++-----------------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 19 insertions(+), 30 deletions(-)

diff --git a/arch/arc/kernel/time.c b/arch/arc/kernel/time.c
index 98f22d2..f927b8d 100644
--- a/arch/arc/kernel/time.c
+++ b/arch/arc/kernel/time.c
@@ -296,30 +296,23 @@ static irqreturn_t timer_irq_handler(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static int arc_timer_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
+
+static int arc_timer_starting_cpu(unsigned int cpu)
{
struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);

evt->cpumask = cpumask_of(smp_processor_id());

- switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_STARTING:
- clockevents_config_and_register(evt, arc_timer_freq,
- 0, ULONG_MAX);
- enable_percpu_irq(arc_timer_irq, 0);
- break;
- case CPU_DYING:
- disable_percpu_irq(arc_timer_irq);
- break;
- }
-
- return NOTIFY_OK;
+ clockevents_config_and_register(evt, arc_timer_freq, 0, ARC_TIMER_MAX);
+ enable_percpu_irq(arc_timer_irq, 0);
+ return 0;
}

-static struct notifier_block arc_timer_cpu_nb = {
- .notifier_call = arc_timer_cpu_notify,
-};
+static int arc_timer_dying_cpu(unsigned int cpu)
+{
+ disable_percpu_irq(arc_timer_irq);
+ return 0;
+}

/*
* clockevent setup for boot CPU
@@ -329,12 +322,6 @@ static int __init arc_clockevent_setup(struct device_node *node)
struct clock_event_device *evt = this_cpu_ptr(&arc_clockevent_device);
int ret;

- ret = register_cpu_notifier(&arc_timer_cpu_nb);
- if (ret) {
- pr_err("Failed to register cpu notifier");
- return ret;
- }
-
arc_timer_irq = irq_of_parse_and_map(node, 0);
if (arc_timer_irq <= 0) {
pr_err("clockevent: missing irq");
@@ -347,11 +334,6 @@ static int __init arc_clockevent_setup(struct device_node *node)
return ret;
}

- evt->irq = arc_timer_irq;
- evt->cpumask = cpumask_of(smp_processor_id());
- clockevents_config_and_register(evt, arc_timer_freq,
- 0, ARC_TIMER_MAX);
-
/* Needs apriori irq_set_percpu_devid() done in intc map function */
ret = request_percpu_irq(arc_timer_irq, timer_irq_handler,
"Timer0 (per-cpu-tick)", evt);
@@ -360,8 +342,14 @@ static int __init arc_clockevent_setup(struct device_node *node)
return ret;
}

- enable_percpu_irq(arc_timer_irq, 0);
-
+ ret = cpuhp_setup_state(CPUHP_AP_ARC_TIMER_STARTING,
+ "AP_ARC_TIMER_STARTING",
+ arc_timer_starting_cpu,
+ arc_timer_dying_cpu);
+ if (ret) {
+ pr_err("Failed to setup hotplug state");
+ return ret;
+ }
return 0;
}

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 5ac59f7..09ef54b 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -56,6 +56,7 @@ enum cpuhp_state {
CPUHP_AP_ARMADA_TIMER_STARTING,
CPUHP_AP_MARCO_TIMER_STARTING,
CPUHP_AP_MIPS_GIC_TIMER_STARTING,
+ CPUHP_AP_ARC_TIMER_STARTING,
CPUHP_AP_KVM_STARTING,
CPUHP_AP_KVM_ARM_VGIC_INIT_STARTING,
CPUHP_AP_KVM_ARM_VGIC_STARTING,