intel_idle: Convert to hotplug state machine

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

The two smp_call_function_single() invocations in intel_idle_cpu_init() have
been removed because intel_idle_cpu_init() is now invoked via the hotplug
callback which runs on the target CPU. The IRQ-off calling convention for
auto_demotion_disable() and c1e_promotion_disable() has not been preserved
because only those two modify the MSR during CPU intialization.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 39 insertions, 64 deletions

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 3828babfb77b..7d8ea3d5fda6 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -98,8 +98,6 @@ static int intel_idle(struct cpuidle_device *dev,
                         struct cpuidle_driver *drv, int index);
 static void intel_idle_freeze(struct cpuidle_device *dev,
                               struct cpuidle_driver *drv, int index);
-static int intel_idle_cpu_init(int cpu);
-
 static struct cpuidle_state *cpuidle_state_table;
 
 /*
@@ -951,50 +949,15 @@ static void intel_idle_freeze(struct cpuidle_device *dev,
         mwait_idle_with_hints(eax, ecx);
 }
 
-static void __setup_broadcast_timer(void *arg)
+static void __setup_broadcast_timer(bool on)
 {
-        unsigned long on = (unsigned long)arg;
-
         if (on)
                 tick_broadcast_enable();
         else
                 tick_broadcast_disable();
 }
 
-static int cpu_hotplug_notify(struct notifier_block *n,
-                              unsigned long action, void *hcpu)
-{
-        int hotcpu = (unsigned long)hcpu;
-        struct cpuidle_device *dev;
-
-        switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_ONLINE:
-
-                if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
-                        __setup_broadcast_timer((void *)true);
-
-                /*
-                 * Some systems can hotplug a cpu at runtime after
-                 * the kernel has booted, we have to initialize the
-                 * driver in this case
-                 */
-                dev = per_cpu_ptr(intel_idle_cpuidle_devices, hotcpu);
-                if (dev->registered)
-                        break;
-
-                if (intel_idle_cpu_init(hotcpu))
-                        return NOTIFY_BAD;
-
-                break;
-        }
-        return NOTIFY_OK;
-}
-
-static struct notifier_block cpu_hotplug_notifier = {
-        .notifier_call = cpu_hotplug_notify,
-};
-
-static void auto_demotion_disable(void *dummy)
+static void auto_demotion_disable(void)
 {
         unsigned long long msr_bits;
 
@@ -1002,7 +965,7 @@ static void auto_demotion_disable(void *dummy)
         msr_bits &= ~(icpu->auto_demotion_disable_flags);
         wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
 }
-static void c1e_promotion_disable(void *dummy)
+static void c1e_promotion_disable(void)
 {
         unsigned long long msr_bits;
 
@@ -1422,12 +1385,11 @@ static void __init intel_idle_cpuidle_driver_init(void)
  * allocate, initialize, register cpuidle_devices
  * @cpu: cpu/core to initialize
  */
-static int intel_idle_cpu_init(int cpu)
+static int intel_idle_cpu_init(unsigned int cpu)
 {
         struct cpuidle_device *dev;
 
         dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
-
         dev->cpu = cpu;
 
         if (cpuidle_register_device(dev)) {
@@ -1436,17 +1398,36 @@ static int intel_idle_cpu_init(int cpu)
         }
 
         if (icpu->auto_demotion_disable_flags)
-                smp_call_function_single(cpu, auto_demotion_disable, NULL, 1);
+                auto_demotion_disable();
 
         if (icpu->disable_promotion_to_c1e)
-                smp_call_function_single(cpu, c1e_promotion_disable, NULL, 1);
+                c1e_promotion_disable();
+
+        return 0;
+}
+
+static int intel_idle_cpu_online(unsigned int cpu)
+{
+        struct cpuidle_device *dev;
+
+        if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
+                __setup_broadcast_timer(true);
+
+        /*
+         * Some systems can hotplug a cpu at runtime after
+         * the kernel has booted, we have to initialize the
+         * driver in this case
+         */
+        dev = per_cpu_ptr(intel_idle_cpuidle_devices, cpu);
+        if (!dev->registered)
+                return intel_idle_cpu_init(cpu);
 
         return 0;
 }
 
 static int __init intel_idle_init(void)
 {
-        int retval, i;
+        int retval;
 
         /* Do not load intel_idle at all for now if idle= is passed */
         if (boot_option_idle_override != IDLE_NO_OVERRIDE)
@@ -1466,35 +1447,29 @@ static int __init intel_idle_init(void)
                 struct cpuidle_driver *drv = cpuidle_get_driver();
                 printk(KERN_DEBUG PREFIX "intel_idle yielding to %s",
                         drv ? drv->name : "none");
-                free_percpu(intel_idle_cpuidle_devices);
-                return retval;
+                goto init_driver_fail;
         }
 
-        cpu_notifier_register_begin();
-
-        for_each_online_cpu(i) {
-                retval = intel_idle_cpu_init(i);
-                if (retval) {
-                        intel_idle_cpuidle_devices_uninit();
-                        cpu_notifier_register_done();
-                        cpuidle_unregister_driver(&intel_idle_driver);
-                        free_percpu(intel_idle_cpuidle_devices);
-                        return retval;
-                }
-        }
-        __register_cpu_notifier(&cpu_hotplug_notifier);
-
         if (boot_cpu_has(X86_FEATURE_ARAT))     /* Always Reliable APIC Timer */
                 lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
-        else
-                on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
 
-        cpu_notifier_register_done();
+        retval = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "idle/intel:online",
+                                   intel_idle_cpu_online, NULL);
+        if (retval < 0)
+                goto hp_setup_fail;
 
         pr_debug(PREFIX "lapic_timer_reliable_states 0x%x\n",
                 lapic_timer_reliable_states);
 
         return 0;
+
+hp_setup_fail:
+        intel_idle_cpuidle_devices_uninit();
+        cpuidle_unregister_driver(&intel_idle_driver);
+init_driver_fail:
+        free_percpu(intel_idle_cpuidle_devices);
+        return retval;
+
 }
 device_initcall(intel_idle_init);