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-rw-r--r--drivers/cpuidle/governor.c119
1 files changed, 119 insertions, 0 deletions
diff --git a/drivers/cpuidle/governor.c b/drivers/cpuidle/governor.c
new file mode 100644
index 000000000..0d0f9751f
--- /dev/null
+++ b/drivers/cpuidle/governor.c
@@ -0,0 +1,119 @@
+/*
+ * 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/cpu.h>
+#include <linux/cpuidle.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/pm_qos.h>
+
+#include "cpuidle.h"
+
+char param_governor[CPUIDLE_NAME_LEN];
+
+LIST_HEAD(cpuidle_governors);
+struct cpuidle_governor *cpuidle_curr_governor;
+struct cpuidle_governor *cpuidle_prev_governor;
+
+/**
+ * cpuidle_find_governor - finds a governor of the specified name
+ * @str: the name
+ *
+ * Must be called with cpuidle_lock acquired.
+ */
+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
+ * Must be called with cpuidle_lock acquired.
+ */
+int cpuidle_switch_governor(struct cpuidle_governor *gov)
+{
+ struct cpuidle_device *dev;
+
+ if (!gov)
+ return -EINVAL;
+
+ 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);
+ }
+
+ cpuidle_curr_governor = gov;
+
+ list_for_each_entry(dev, &cpuidle_detected_devices, device_list)
+ cpuidle_enable_device(dev);
+
+ cpuidle_install_idle_handler();
+ pr_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 ||
+ !strncasecmp(param_governor, gov->name, CPUIDLE_NAME_LEN) ||
+ (cpuidle_curr_governor->rating < gov->rating &&
+ strncasecmp(param_governor, cpuidle_curr_governor->name,
+ CPUIDLE_NAME_LEN)))
+ cpuidle_switch_governor(gov);
+ }
+ mutex_unlock(&cpuidle_lock);
+
+ return ret;
+}
+
+/**
+ * cpuidle_governor_latency_req - Compute a latency constraint for CPU
+ * @cpu: Target CPU
+ */
+s64 cpuidle_governor_latency_req(unsigned int cpu)
+{
+ struct device *device = get_cpu_device(cpu);
+ int device_req = dev_pm_qos_raw_resume_latency(device);
+ int global_req = cpu_latency_qos_limit();
+
+ if (device_req > global_req)
+ device_req = global_req;
+
+ return (s64)device_req * NSEC_PER_USEC;
+}