1 files changed, 137 insertions, 0 deletions
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
new file mode 100644
index 00000000000..299d45c3bdd
--- /dev/null
+++ b/drivers/cpuidle/governors/menu.c
@@ -0,0 +1,137 @@
+/*
+ * menu.c - the menu idle governor
+ *
+ * Copyright (C) 2006-2007 Adam Belay <abelay@novell.com>
+ *
+ * This code is licenced under the GPL.
+ */
+
+#include <linux/kernel.h>
+#include <linux/cpuidle.h>
+#include <linux/latency.h>
+#include <linux/time.h>
+#include <linux/ktime.h>
+#include <linux/hrtimer.h>
+#include <linux/tick.h>
+
+#define BREAK_FUZZ	4	/* 4 us */
+
+struct menu_device {
+	int		last_state_idx;
+
+	unsigned int	expected_us;
+	unsigned int	predicted_us;
+	unsigned int	last_measured_us;
+	unsigned int	elapsed_us;
+};
+
+static DEFINE_PER_CPU(struct menu_device, menu_devices);
+
+/**
+ * menu_select - selects the next idle state to enter
+ * @dev: the CPU
+ */
+static int menu_select(struct cpuidle_device *dev)
+{
+	struct menu_device *data = &__get_cpu_var(menu_devices);
+	int i;
+
+	/* determine the expected residency time */
+	data->expected_us =
+		(u32) ktime_to_ns(tick_nohz_get_sleep_length()) / 1000;
+
+	/* find the deepest idle state that satisfies our constraints */
+	for (i = 1; i < dev->state_count; i++) {
+		struct cpuidle_state *s = &dev->states[i];
+
+		if (s->target_residency > data->expected_us)
+			break;
+		if (s->target_residency > data->predicted_us)
+			break;
+		if (s->exit_latency > system_latency_constraint())
+			break;
+	}
+
+	data->last_state_idx = i - 1;
+	return i - 1;
+}
+
+/**
+ * menu_reflect - attempts to guess what happened after entry
+ * @dev: the CPU
+ *
+ * NOTE: it's important to be fast here because this operation will add to
+ *       the overall exit latency.
+ */
+static void menu_reflect(struct cpuidle_device *dev)
+{
+	struct menu_device *data = &__get_cpu_var(menu_devices);
+	int last_idx = data->last_state_idx;
+	unsigned int measured_us =
+		cpuidle_get_last_residency(dev) + data->elapsed_us;
+	struct cpuidle_state *target = &dev->states[last_idx];
+
+	/*
+	 * Ugh, this idle state doesn't support residency measurements, so we
+	 * are basically lost in the dark.  As a compromise, assume we slept
+	 * for one full standard timer tick.  However, be aware that this
+	 * could potentially result in a suboptimal state transition.
+	 */
+	if (!(target->flags & CPUIDLE_FLAG_TIME_VALID))
+		measured_us = USEC_PER_SEC / HZ;
+
+	/* Predict time remaining until next break event */
+	if (measured_us + BREAK_FUZZ < data->expected_us - target->exit_latency) {
+		data->predicted_us = max(measured_us, data->last_measured_us);
+		data->last_measured_us = measured_us;
+		data->elapsed_us = 0;
+	} else {
+		if (data->elapsed_us < data->elapsed_us + measured_us)
+			data->elapsed_us = measured_us;
+		else
+			data->elapsed_us = -1;
+		data->predicted_us = max(measured_us, data->last_measured_us);
+	}
+}
+
+/**
+ * menu_enable_device - scans a CPU's states and does setup
+ * @dev: the CPU
+ */
+static int menu_enable_device(struct cpuidle_device *dev)
+{
+	struct menu_device *data = &per_cpu(menu_devices, dev->cpu);
+
+	memset(data, 0, sizeof(struct menu_device));
+
+	return 0;
+}
+
+static struct cpuidle_governor menu_governor = {
+	.name =		"menu",
+	.rating =	20,
+	.enable =	menu_enable_device,
+	.select =	menu_select,
+	.reflect =	menu_reflect,
+	.owner =	THIS_MODULE,
+};
+
+/**
+ * init_menu - initializes the governor
+ */
+static int __init init_menu(void)
+{
+	return cpuidle_register_governor(&menu_governor);
+}
+
+/**
+ * exit_menu - exits the governor
+ */
+static void __exit exit_menu(void)
+{
+	cpuidle_unregister_governor(&menu_governor);
+}
+
+MODULE_LICENSE("GPL");
+module_init(init_menu);
+module_exit(exit_menu);