Initial import

1 files changed, 294 insertions, 0 deletions

diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h
new file mode 100644
index 000000000..ce447f0f1
--- /dev/null
+++ b/include/linux/devfreq.h
@@ -0,0 +1,294 @@
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ *	    for Non-CPU Devices.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ *	MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __LINUX_DEVFREQ_H__
+#define __LINUX_DEVFREQ_H__
+
+#include <linux/device.h>
+#include <linux/notifier.h>
+#include <linux/pm_opp.h>
+
+#define DEVFREQ_NAME_LEN 16
+
+struct devfreq;
+
+/**
+ * struct devfreq_dev_status - Data given from devfreq user device to
+ *			     governors. Represents the performance
+ *			     statistics.
+ * @total_time:		The total time represented by this instance of
+ *			devfreq_dev_status
+ * @busy_time:		The time that the device was working among the
+ *			total_time.
+ * @current_frequency:	The operating frequency.
+ * @private_data:	An entry not specified by the devfreq framework.
+ *			A device and a specific governor may have their
+ *			own protocol with private_data. However, because
+ *			this is governor-specific, a governor using this
+ *			will be only compatible with devices aware of it.
+ */
+struct devfreq_dev_status {
+	/* both since the last measure */
+	unsigned long total_time;
+	unsigned long busy_time;
+	unsigned long current_frequency;
+	void *private_data;
+};
+
+/*
+ * The resulting frequency should be at most this. (this bound is the
+ * least upper bound; thus, the resulting freq should be lower or same)
+ * If the flag is not set, the resulting frequency should be at most the
+ * bound (greatest lower bound)
+ */
+#define DEVFREQ_FLAG_LEAST_UPPER_BOUND		0x1
+
+/**
+ * struct devfreq_dev_profile - Devfreq's user device profile
+ * @initial_freq:	The operating frequency when devfreq_add_device() is
+ *			called.
+ * @polling_ms:		The polling interval in ms. 0 disables polling.
+ * @target:		The device should set its operating frequency at
+ *			freq or lowest-upper-than-freq value. If freq is
+ *			higher than any operable frequency, set maximum.
+ *			Before returning, target function should set
+ *			freq at the current frequency.
+ *			The "flags" parameter's possible values are
+ *			explained above with "DEVFREQ_FLAG_*" macros.
+ * @get_dev_status:	The device should provide the current performance
+ *			status to devfreq, which is used by governors.
+ * @get_cur_freq:	The device should provide the current frequency
+ *			at which it is operating.
+ * @exit:		An optional callback that is called when devfreq
+ *			is removing the devfreq object due to error or
+ *			from devfreq_remove_device() call. If the user
+ *			has registered devfreq->nb at a notifier-head,
+ *			this is the time to unregister it.
+ * @freq_table:	Optional list of frequencies to support statistics.
+ * @max_state:	The size of freq_table.
+ */
+struct devfreq_dev_profile {
+	unsigned long initial_freq;
+	unsigned int polling_ms;
+
+	int (*target)(struct device *dev, unsigned long *freq, u32 flags);
+	int (*get_dev_status)(struct device *dev,
+			      struct devfreq_dev_status *stat);
+	int (*get_cur_freq)(struct device *dev, unsigned long *freq);
+	void (*exit)(struct device *dev);
+
+	unsigned int *freq_table;
+	unsigned int max_state;
+};
+
+/**
+ * struct devfreq_governor - Devfreq policy governor
+ * @node:		list node - contains registered devfreq governors
+ * @name:		Governor's name
+ * @get_target_freq:	Returns desired operating frequency for the device.
+ *			Basically, get_target_freq will run
+ *			devfreq_dev_profile.get_dev_status() to get the
+ *			status of the device (load = busy_time / total_time).
+ *			If no_central_polling is set, this callback is called
+ *			only with update_devfreq() notified by OPP.
+ * @event_handler:      Callback for devfreq core framework to notify events
+ *                      to governors. Events include per device governor
+ *                      init and exit, opp changes out of devfreq, suspend
+ *                      and resume of per device devfreq during device idle.
+ *
+ * Note that the callbacks are called with devfreq->lock locked by devfreq.
+ */
+struct devfreq_governor {
+	struct list_head node;
+
+	const char name[DEVFREQ_NAME_LEN];
+	int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
+	int (*event_handler)(struct devfreq *devfreq,
+				unsigned int event, void *data);
+};
+
+/**
+ * struct devfreq - Device devfreq structure
+ * @node:	list node - contains the devices with devfreq that have been
+ *		registered.
+ * @lock:	a mutex to protect accessing devfreq.
+ * @dev:	device registered by devfreq class. dev.parent is the device
+ *		using devfreq.
+ * @profile:	device-specific devfreq profile
+ * @governor:	method how to choose frequency based on the usage.
+ * @governor_name:	devfreq governor name for use with this devfreq
+ * @nb:		notifier block used to notify devfreq object that it should
+ *		reevaluate operable frequencies. Devfreq users may use
+ *		devfreq.nb to the corresponding register notifier call chain.
+ * @work:	delayed work for load monitoring.
+ * @previous_freq:	previously configured frequency value.
+ * @data:	Private data of the governor. The devfreq framework does not
+ *		touch this.
+ * @min_freq:	Limit minimum frequency requested by user (0: none)
+ * @max_freq:	Limit maximum frequency requested by user (0: none)
+ * @stop_polling:	 devfreq polling status of a device.
+ * @total_trans:	Number of devfreq transitions
+ * @trans_table:	Statistics of devfreq transitions
+ * @time_in_state:	Statistics of devfreq states
+ * @last_stat_updated:	The last time stat updated
+ *
+ * This structure stores the devfreq information for a give device.
+ *
+ * Note that when a governor accesses entries in struct devfreq in its
+ * functions except for the context of callbacks defined in struct
+ * devfreq_governor, the governor should protect its access with the
+ * struct mutex lock in struct devfreq. A governor may use this mutex
+ * to protect its own private data in void *data as well.
+ */
+struct devfreq {
+	struct list_head node;
+
+	struct mutex lock;
+	struct device dev;
+	struct devfreq_dev_profile *profile;
+	const struct devfreq_governor *governor;
+	char governor_name[DEVFREQ_NAME_LEN];
+	struct notifier_block nb;
+	struct delayed_work work;
+
+	unsigned long previous_freq;
+
+	void *data; /* private data for governors */
+
+	unsigned long min_freq;
+	unsigned long max_freq;
+	bool stop_polling;
+
+	/* information for device frequency transition */
+	unsigned int total_trans;
+	unsigned int *trans_table;
+	unsigned long *time_in_state;
+	unsigned long last_stat_updated;
+};
+
+#if defined(CONFIG_PM_DEVFREQ)
+extern struct devfreq *devfreq_add_device(struct device *dev,
+				  struct devfreq_dev_profile *profile,
+				  const char *governor_name,
+				  void *data);
+extern int devfreq_remove_device(struct devfreq *devfreq);
+extern struct devfreq *devm_devfreq_add_device(struct device *dev,
+				  struct devfreq_dev_profile *profile,
+				  const char *governor_name,
+				  void *data);
+extern void devm_devfreq_remove_device(struct device *dev,
+				  struct devfreq *devfreq);
+
+/* Supposed to be called by PM callbacks */
+extern int devfreq_suspend_device(struct devfreq *devfreq);
+extern int devfreq_resume_device(struct devfreq *devfreq);
+
+/* Helper functions for devfreq user device driver with OPP. */
+extern struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
+					   unsigned long *freq, u32 flags);
+extern int devfreq_register_opp_notifier(struct device *dev,
+					 struct devfreq *devfreq);
+extern int devfreq_unregister_opp_notifier(struct device *dev,
+					   struct devfreq *devfreq);
+extern int devm_devfreq_register_opp_notifier(struct device *dev,
+					      struct devfreq *devfreq);
+extern void devm_devfreq_unregister_opp_notifier(struct device *dev,
+						struct devfreq *devfreq);
+
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND)
+/**
+ * struct devfreq_simple_ondemand_data - void *data fed to struct devfreq
+ *	and devfreq_add_device
+ * @upthreshold:	If the load is over this value, the frequency jumps.
+ *			Specify 0 to use the default. Valid value = 0 to 100.
+ * @downdifferential:	If the load is under upthreshold - downdifferential,
+ *			the governor may consider slowing the frequency down.
+ *			Specify 0 to use the default. Valid value = 0 to 100.
+ *			downdifferential < upthreshold must hold.
+ *
+ * If the fed devfreq_simple_ondemand_data pointer is NULL to the governor,
+ * the governor uses the default values.
+ */
+struct devfreq_simple_ondemand_data {
+	unsigned int upthreshold;
+	unsigned int downdifferential;
+};
+#endif
+
+#else /* !CONFIG_PM_DEVFREQ */
+static inline struct devfreq *devfreq_add_device(struct device *dev,
+					  struct devfreq_dev_profile *profile,
+					  const char *governor_name,
+					  void *data)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline int devfreq_remove_device(struct devfreq *devfreq)
+{
+	return 0;
+}
+
+static inline struct devfreq *devm_devfreq_add_device(struct device *dev,
+					struct devfreq_dev_profile *profile,
+					const char *governor_name,
+					void *data)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
+static inline void devm_devfreq_remove_device(struct device *dev,
+					struct devfreq *devfreq)
+{
+}
+
+static inline int devfreq_suspend_device(struct devfreq *devfreq)
+{
+	return 0;
+}
+
+static inline int devfreq_resume_device(struct devfreq *devfreq)
+{
+	return 0;
+}
+
+static inline struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
+					   unsigned long *freq, u32 flags)
+{
+	return ERR_PTR(-EINVAL);
+}
+
+static inline int devfreq_register_opp_notifier(struct device *dev,
+					 struct devfreq *devfreq)
+{
+	return -EINVAL;
+}
+
+static inline int devfreq_unregister_opp_notifier(struct device *dev,
+					   struct devfreq *devfreq)
+{
+	return -EINVAL;
+}
+
+static inline int devm_devfreq_register_opp_notifier(struct device *dev,
+						     struct devfreq *devfreq)
+{
+	return -EINVAL;
+}
+
+static inline void devm_devfreq_unregister_opp_notifier(struct device *dev,
+							struct devfreq *devfreq)
+{
+}
+#endif /* CONFIG_PM_DEVFREQ */
+
+#endif /* __LINUX_DEVFREQ_H__ */