Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / drivers / cpuidle / governor.c

diff --git a/kernel/drivers/cpuidle/governor.c b/kernel/drivers/cpuidle/governor.c
new file mode 100644 (file)
index 0000000..fb9f511
--- /dev/null
+++ b/kernel/drivers/cpuidle/governor.c
@@ -0,0 +1,98 @@
+/*
+ * governor.c - governor support
+ *
+ * (C) 2006-2007 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ *               Shaohua Li <shaohua.li@intel.com>
+ *               Adam Belay <abelay@novell.com>
+ *
+ * This code is licenced under the GPL.
+ */
+
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/cpuidle.h>
+
+#include "cpuidle.h"
+
+LIST_HEAD(cpuidle_governors);
+struct cpuidle_governor *cpuidle_curr_governor;
+
+/**
+ * __cpuidle_find_governor - finds a governor of the specified name
+ * @str: the name
+ *
+ * Must be called with cpuidle_lock acquired.
+ */
+static struct cpuidle_governor * __cpuidle_find_governor(const char *str)
+{
+       struct cpuidle_governor *gov;
+
+       list_for_each_entry(gov, &cpuidle_governors, governor_list)
+               if (!strncasecmp(str, gov->name, CPUIDLE_NAME_LEN))
+                       return gov;
+
+       return NULL;
+}
+
+/**
+ * cpuidle_switch_governor - changes the governor
+ * @gov: the new target governor
+ *
+ * NOTE: "gov" can be NULL to specify disabled
+ * Must be called with cpuidle_lock acquired.
+ */
+int cpuidle_switch_governor(struct cpuidle_governor *gov)
+{
+       struct cpuidle_device *dev;
+
+       if (gov == cpuidle_curr_governor)
+               return 0;
+
+       cpuidle_uninstall_idle_handler();
+
+       if (cpuidle_curr_governor) {
+               list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
+                       cpuidle_disable_device(dev);
+               module_put(cpuidle_curr_governor->owner);
+       }
+
+       cpuidle_curr_governor = gov;
+
+       if (gov) {
+               if (!try_module_get(cpuidle_curr_governor->owner))
+                       return -EINVAL;
+               list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
+                       cpuidle_enable_device(dev);
+               cpuidle_install_idle_handler();
+               printk(KERN_INFO "cpuidle: using governor %s\n", gov->name);
+       }
+
+       return 0;
+}
+
+/**
+ * cpuidle_register_governor - registers a governor
+ * @gov: the governor
+ */
+int cpuidle_register_governor(struct cpuidle_governor *gov)
+{
+       int ret = -EEXIST;
+
+       if (!gov || !gov->select)
+               return -EINVAL;
+
+       if (cpuidle_disabled())
+               return -ENODEV;
+
+       mutex_lock(&cpuidle_lock);
+       if (__cpuidle_find_governor(gov->name) == NULL) {
+               ret = 0;
+               list_add_tail(&gov->governor_list, &cpuidle_governors);
+               if (!cpuidle_curr_governor ||
+                   cpuidle_curr_governor->rating < gov->rating)
+                       cpuidle_switch_governor(gov);
+       }
+       mutex_unlock(&cpuidle_lock);
+
+       return ret;
+}