cpufreq: Move get_cpu_idle_time() to cpufreq.c

Governors other than ondemand and conservative can also use
get_cpu_idle_time() and they aren't required to compile
cpufreq_governor.c. So, move these independent routines to
cpufreq.c instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 3faf62b..c6ab218 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -17,7 +17,9 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <asm/cputime.h>
 #include <linux/kernel.h>
+#include <linux/kernel_stat.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/notifier.h>
@@ -25,6 +27,7 @@
 #include <linux/delay.h>
 #include <linux/interrupt.h>
 #include <linux/spinlock.h>
+#include <linux/tick.h>
 #include <linux/device.h>
 #include <linux/slab.h>
 #include <linux/cpu.h>
@@ -143,6 +146,41 @@
 }
 EXPORT_SYMBOL_GPL(get_governor_parent_kobj);
 
+static inline u64 get_cpu_idle_time_jiffy(unsigned int cpu, u64 *wall)
+{
+	u64 idle_time;
+	u64 cur_wall_time;
+	u64 busy_time;
+
+	cur_wall_time = jiffies64_to_cputime64(get_jiffies_64());
+
+	busy_time = kcpustat_cpu(cpu).cpustat[CPUTIME_USER];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SYSTEM];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_IRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_SOFTIRQ];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_STEAL];
+	busy_time += kcpustat_cpu(cpu).cpustat[CPUTIME_NICE];
+
+	idle_time = cur_wall_time - busy_time;
+	if (wall)
+		*wall = cputime_to_usecs(cur_wall_time);
+
+	return cputime_to_usecs(idle_time);
+}
+
+u64 get_cpu_idle_time(unsigned int cpu, u64 *wall, int io_busy)
+{
+	u64 idle_time = get_cpu_idle_time_us(cpu, io_busy ? wall : NULL);
+
+	if (idle_time == -1ULL)
+		return get_cpu_idle_time_jiffy(cpu, wall);
+	else if (!io_busy)
+		idle_time += get_cpu_iowait_time_us(cpu, wall);
+
+	return idle_time;
+}
+EXPORT_SYMBOL_GPL(get_cpu_idle_time);
+
 static struct cpufreq_policy *__cpufreq_cpu_get(unsigned int cpu, bool sysfs)
 {
 	struct cpufreq_policy *data;