ACPI: intel_idle : break dependency between modules

When the system is booted with some cpus offline, the idle
driver is not initialized. When a cpu is set online, the
acpi code call the intel idle init function. Unfortunately
this code introduce a dependency between intel_idle and acpi.

This patch is intended to remove this dependency by using the
notifier of intel_idle. This patch has the benefit of
encapsulating the intel_idle driver and remove some exported
functions.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index 0734086537b89732ba805158389b904e94ae7ecf..8648b29f6eec1be303f4e17d3fc21c4fa69e2f99 100644 (file)
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -427,18 +427,11 @@ static int acpi_cpu_soft_notify(struct notifier_block *nfb,
                 * Initialize missing things
                 */
                if (pr->flags.need_hotplug_init) {
-                       struct cpuidle_driver *idle_driver =
-                               cpuidle_get_driver();
-
                        printk(KERN_INFO "Will online and init hotplugged "
                               "CPU: %d\n", pr->id);
                        WARN(acpi_processor_start(pr), "Failed to start CPU:"
                                " %d\n", pr->id);
                        pr->flags.need_hotplug_init = 0;
-                       if (idle_driver && !strcmp(idle_driver->name,
-                                                  "intel_idle")) {
-                               intel_idle_cpu_init(pr->id);
-                       }
                /* Normal CPU soft online event */
                } else {
                        acpi_processor_ppc_has_changed(pr, 0);

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index d0f59c3f87eff08c9af04bd7d13f2b91e6f3ea17..fe95d5464a0251470cb9f094f4e7bc5922f1e3c8 100644 (file)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -96,6 +96,7 @@ static const struct idle_cpu *icpu;
 static struct cpuidle_device __percpu *intel_idle_cpuidle_devices;
 static int intel_idle(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;
 
@@ -302,22 +303,35 @@ static void __setup_broadcast_timer(void *arg)
        clockevents_notify(reason, &cpu);
 }
 
-static int setup_broadcast_cpuhp_notify(struct notifier_block *n,
-               unsigned long action, void *hcpu)
+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 & 0xf) {
        case CPU_ONLINE:
-               smp_call_function_single(hotcpu, __setup_broadcast_timer,
-                       (void *)true, 1);
+
+               if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
+                       smp_call_function_single(hotcpu, __setup_broadcast_timer,
+                                                (void *)true, 1);
+
+               /*
+                * 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)
+                       intel_idle_cpu_init(hotcpu);
+
                break;
        }
        return NOTIFY_OK;
 }
 
-static struct notifier_block setup_broadcast_notifier = {
-       .notifier_call = setup_broadcast_cpuhp_notify,
+static struct notifier_block cpu_hotplug_notifier = {
+       .notifier_call = cpu_hotplug_notify,
 };
 
 static void auto_demotion_disable(void *dummy)
@@ -405,10 +419,10 @@ static int intel_idle_probe(void)
 
        if (boot_cpu_has(X86_FEATURE_ARAT))     /* Always Reliable APIC Timer */
                lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
-       else {
+       else
                on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
-               register_cpu_notifier(&setup_broadcast_notifier);
-       }
+
+       register_cpu_notifier(&cpu_hotplug_notifier);
 
        pr_debug(PREFIX "v" INTEL_IDLE_VERSION
                " model 0x%X\n", boot_cpu_data.x86_model);
@@ -494,7 +508,7 @@ static int intel_idle_cpuidle_driver_init(void)
  * allocate, initialize, register cpuidle_devices
  * @cpu: cpu/core to initialize
  */
-int intel_idle_cpu_init(int cpu)
+static int intel_idle_cpu_init(int cpu)
 {
        int cstate;
        struct cpuidle_device *dev;
@@ -539,7 +553,6 @@ int intel_idle_cpu_init(int cpu)
 
        return 0;
 }
-EXPORT_SYMBOL_GPL(intel_idle_cpu_init);
 
 static int __init intel_idle_init(void)
 {
@@ -581,10 +594,10 @@ static void __exit intel_idle_exit(void)
        intel_idle_cpuidle_devices_uninit();
        cpuidle_unregister_driver(&intel_idle_driver);
 
-       if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
+
+       if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE)
                on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
-               unregister_cpu_notifier(&setup_broadcast_notifier);
-       }
+       unregister_cpu_notifier(&cpu_hotplug_notifier);
 
        return;
 }

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 27cfced7b57bac1c00e5e538d2f62dcbf4a50907..524bb6f3b6c49611ccb4ccb37d711b52649a8ecb 100644 (file)
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -206,14 +206,7 @@ struct cpuidle_governor {
 extern int cpuidle_register_governor(struct cpuidle_governor *gov);
 extern void cpuidle_unregister_governor(struct cpuidle_governor *gov);
 
-#ifdef CONFIG_INTEL_IDLE
-extern int intel_idle_cpu_init(int cpu);
 #else
-static inline int intel_idle_cpu_init(int cpu) { return -1; }
-#endif
-
-#else
-static inline int intel_idle_cpu_init(int cpu) { return -1; }
 
 static inline int cpuidle_register_governor(struct cpuidle_governor *gov)
 {return 0;}