[PATCH][V3] cpuidle : use percpu cpuidle in the core code

[Daniel Lezcano <daniel.lezcano@linaro.org>]

The usual cpuidle initialization routines register the driver and
then register a cpuidle device per cpu.

By default, most drivers initialize the device state count with the
driver state count.

We can then add a new function 'cpuidle_register' where we register
the driver and the devices. These devices can be defined in a global
static variable in cpuidle.c. We will be able to factor out and
remove a lot of duplicate lines of code.

As we still have some drivers, with different initialization routines,
we keep 'cpuidle_register_driver' and 'cpuidle_register_device' as low
level initialization routines to do some specific operations on the
cpuidle devices.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/cpuidle/cpuidle.c |   42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/cpuidle.h   |    3 +++
 2 files changed, 45 insertions(+), 0 deletions(-)

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 87411ce..4d1f79b 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -23,6 +23,7 @@
 #include "cpuidle.h"
 
 DEFINE_PER_CPU(struct cpuidle_device *, cpuidle_devices);
+DEFINE_PER_CPU(struct cpuidle_device, cpuidle_device);
 
 DEFINE_MUTEX(cpuidle_lock);
 LIST_HEAD(cpuidle_detected_devices);
@@ -419,6 +420,47 @@ int cpuidle_register_device(struct cpuidle_device *dev)
 
 EXPORT_SYMBOL_GPL(cpuidle_register_device);
 
+/*
+ * cpuidle_register : register cpuidle driver and devices
+ * Note this function must be called after smp_init.
+ * @drv : the cpuidle driver
+ * Returns 0 on success, < 0 otherwise
+ */
+int cpuidle_register(struct cpuidle_driver *drv)
+{
+	int ret, cpu, i;
+	struct cpuidle_device *dev;
+
+	ret = cpuidle_register_driver(drv);
+	if (ret)
+		return ret;
+
+	for_each_online_cpu(cpu) {
+		dev = &per_cpu(cpuidle_device, cpu);
+		dev->cpu = cpu;
+
+		ret = cpuidle_register_device(dev);
+		if (ret)
+			goto out_unregister;
+	}
+
+out:
+	return ret;
+
+out_unregister:
+	for_each_online_cpu(i) {
+		if (i == cpu)
+			break;
+		dev = &per_cpu(cpuidle_device, i);
+		cpuidle_unregister_device(dev);
+	}
+
+	cpuidle_unregister_driver(drv);
+
+	goto out;
+}
+EXPORT_SYMBOL_GPL(cpuidle_register);
+
 /**
  * cpuidle_unregister_device - unregisters a CPU's idle PM feature
  * @dev: the cpu
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 6c26a3d..3475294 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -135,6 +135,7 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 extern int cpuidle_idle_call(void);
+extern int cpuidle_register(struct cpuidle_driver *drv);
 extern int cpuidle_register_driver(struct cpuidle_driver *drv);
 struct cpuidle_driver *cpuidle_get_driver(void);
 extern void cpuidle_unregister_driver(struct cpuidle_driver *drv);
@@ -154,6 +155,8 @@ extern int cpuidle_play_dead(void);
 #else
 static inline void disable_cpuidle(void) { }
 static inline int cpuidle_idle_call(void) { return -ENODEV; }
+static inline int cpuidle_register(struct cpuidle_driver *drv)
+{return -ENODEV; }
 static inline int cpuidle_register_driver(struct cpuidle_driver *drv)
 {return -ENODEV; }
 static inline struct cpuidle_driver *cpuidle_get_driver(void) {return NULL; }
-- 
1.7.5.4