[PATCH 10/16 v2] cpuidle: pseries: Convert to hotplug state machine

[Sebastian Andrzej Siewior]

Install the callbacks via the state machine.

v1…v2: Use only CPUHP_CPUIDLE_DEAD (requested by Daniel Lezcano)

Cc: "Rafael J. Wysocki" <r...@rjwysocki.net>
Cc: Daniel Lezcano <daniel.lezc...@linaro.org>
Cc: linux...@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
 drivers/cpuidle/cpuidle-pseries.c | 53 ++++++++++++++++++---------------------
 include/linux/cpuhotplug.h        |  1 +
 2 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/drivers/cpuidle/cpuidle-pseries.c 
b/drivers/cpuidle/cpuidle-pseries.c
index 07135e009d8b..abbce8f96d93 100644
--- a/drivers/cpuidle/cpuidle-pseries.c
+++ b/drivers/cpuidle/cpuidle-pseries.c
@@ -171,39 +171,29 @@ static struct cpuidle_state shared_states[] = {
                .enter = &shared_cede_loop },
 };
 
-static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,
-                       unsigned long action, void *hcpu)
+static int pseries_cpuidle_cpu_online(unsigned int cpu)
 {
-       int hotcpu = (unsigned long)hcpu;
-       struct cpuidle_device *dev =
-                               per_cpu(cpuidle_devices, hotcpu);
+       struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
 
        if (dev && cpuidle_get_driver()) {
-               switch (action) {
-               case CPU_ONLINE:
-               case CPU_ONLINE_FROZEN:
-                       cpuidle_pause_and_lock();
-                       cpuidle_enable_device(dev);
-                       cpuidle_resume_and_unlock();
-                       break;
-
-               case CPU_DEAD:
-               case CPU_DEAD_FROZEN:
-                       cpuidle_pause_and_lock();
-                       cpuidle_disable_device(dev);
-                       cpuidle_resume_and_unlock();
-                       break;
-
-               default:
-                       return NOTIFY_DONE;
-               }
+               cpuidle_pause_and_lock();
+               cpuidle_enable_device(dev);
+               cpuidle_resume_and_unlock();
        }
-       return NOTIFY_OK;
+       return 0;
 }
 
-static struct notifier_block setup_hotplug_notifier = {
-       .notifier_call = pseries_cpuidle_add_cpu_notifier,
-};
+static int pseries_cpuidle_cpu_dead(unsigned int cpu)
+{
+       struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
+
+       if (dev && cpuidle_get_driver()) {
+               cpuidle_pause_and_lock();
+               cpuidle_disable_device(dev);
+               cpuidle_resume_and_unlock();
+       }
+       return 0;
+}
 
 /*
  * pseries_cpuidle_driver_init()
@@ -273,7 +263,14 @@ static int __init pseries_processor_idle_init(void)
                return retval;
        }
 
-       register_cpu_notifier(&setup_hotplug_notifier);
+       retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+                                          "CPUIDLE_PSERIES_ONLINE",
+                                          pseries_cpuidle_cpu_online, NULL);
+       WARN_ON(retval < 0);
+       retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD,
+                                          "CPUIDLE_PSERIES_DEAD", NULL,
+                                          pseries_cpuidle_cpu_dead);
+       WARN_ON(retval < 0);
        printk(KERN_DEBUG "pseries_idle_driver registered\n");
        return 0;
 }
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 5811954809af..14b58a9d1450 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -19,6 +19,7 @@ enum cpuhp_state {
        CPUHP_MM_WRITEBACK_DEAD,
        CPUHP_SOFTIRQ_DEAD,
        CPUHP_NET_MVNETA_DEAD,
+       CPUHP_CPUIDLE_DEAD,
        CPUHP_WORKQUEUE_PREP,
        CPUHP_POWER_NUMA_PREPARE,
        CPUHP_HRTIMERS_PREPARE,
-- 
2.9.3