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Release 4.14 drivers/devfreq/devfreq.c

Directory: drivers/devfreq
 * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
 *          for Non-CPU Devices.
 * Copyright (C) 2011 Samsung Electronics
 *      MyungJoo Ham <>
 * 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.

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/pm_opp.h>
#include <linux/devfreq.h>
#include <linux/workqueue.h>
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/printk.h>
#include <linux/hrtimer.h>
#include <linux/of.h>
#include "governor.h"

static struct class *devfreq_class;

 * devfreq core provides delayed work based load monitoring helper
 * functions. Governors can use these or can implement their own
 * monitoring mechanism.

static struct workqueue_struct *devfreq_wq;

/* The list of all device-devfreq governors */
static LIST_HEAD(devfreq_governor_list);
/* The list of all device-devfreq */
static LIST_HEAD(devfreq_list);
static DEFINE_MUTEX(devfreq_list_lock);

 * find_device_devfreq() - find devfreq struct using device pointer
 * @dev:        device pointer used to lookup device devfreq.
 * Search the list of device devfreqs and return the matched device's
 * devfreq info. devfreq_list_lock should be held by the caller.

static struct devfreq *find_device_devfreq(struct device *dev) { struct devfreq *tmp_devfreq; if (IS_ERR_OR_NULL(dev)) { pr_err("DEVFREQ: %s: Invalid parameters\n", __func__); return ERR_PTR(-EINVAL); } WARN(!mutex_is_locked(&devfreq_list_lock), "devfreq_list_lock must be locked."); list_for_each_entry(tmp_devfreq, &devfreq_list, node) { if (tmp_devfreq->dev.parent == dev) return tmp_devfreq; } return ERR_PTR(-ENODEV); }


MyungJoo Ham83100.00%1100.00%

/** * devfreq_get_freq_level() - Lookup freq_table for the frequency * @devfreq: the devfreq instance * @freq: the target frequency */
static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq) { int lev; for (lev = 0; lev < devfreq->profile->max_state; lev++) if (freq == devfreq->profile->freq_table[lev]) return lev; return -EINVAL; }


Jonghwa Lee3360.00%133.33%
MyungJoo Ham2240.00%266.67%

/** * devfreq_set_freq_table() - Initialize freq_table for the frequency * @devfreq: the devfreq instance */
static void devfreq_set_freq_table(struct devfreq *devfreq) { struct devfreq_dev_profile *profile = devfreq->profile; struct dev_pm_opp *opp; unsigned long freq; int i, count; /* Initialize the freq_table from OPP table */ count = dev_pm_opp_get_opp_count(devfreq->dev.parent); if (count <= 0) return; profile->max_state = count; profile->freq_table = devm_kcalloc(devfreq->dev.parent, profile->max_state, sizeof(*profile->freq_table), GFP_KERNEL); if (!profile->freq_table) { profile->max_state = 0; return; } for (i = 0, freq = 0; i < profile->max_state; i++, freq++) { opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq); if (IS_ERR(opp)) { devm_kfree(devfreq->dev.parent, profile->freq_table); profile->max_state = 0; return; } dev_pm_opp_put(opp); profile->freq_table[i] = freq; } }


Chanwoo Choi17897.27%150.00%
Viresh Kumar52.73%150.00%

/** * devfreq_update_status() - Update statistics of devfreq behavior * @devfreq: the devfreq instance * @freq: the update target frequency */
int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) { int lev, prev_lev, ret = 0; unsigned long cur_time; cur_time = jiffies; /* Immediately exit if previous_freq is not initialized yet. */ if (!devfreq->previous_freq) goto out; prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq); if (prev_lev < 0) { ret = prev_lev; goto out; } devfreq->time_in_state[prev_lev] += cur_time - devfreq->last_stat_updated; lev = devfreq_get_freq_level(devfreq, freq); if (lev < 0) { ret = lev; goto out; } if (lev != prev_lev) { devfreq->trans_table[(prev_lev * devfreq->profile->max_state) + lev]++; devfreq->total_trans++; } out: devfreq->last_stat_updated = cur_time; return ret; }


Jonghwa Lee5839.46%120.00%
Saravana Kannan4832.65%120.00%
MyungJoo Ham3020.41%240.00%
Tobias Jakobi117.48%120.00%

EXPORT_SYMBOL(devfreq_update_status); /** * find_devfreq_governor() - find devfreq governor from name * @name: name of the governor * * Search the list of devfreq governors and return the matched * governor's pointer. devfreq_list_lock should be held by the caller. */
static struct devfreq_governor *find_devfreq_governor(const char *name) { struct devfreq_governor *tmp_governor; if (IS_ERR_OR_NULL(name)) { pr_err("DEVFREQ: %s: Invalid parameters\n", __func__); return ERR_PTR(-EINVAL); } WARN(!mutex_is_locked(&devfreq_list_lock), "devfreq_list_lock must be locked."); list_for_each_entry(tmp_governor, &devfreq_governor_list, node) { if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN)) return tmp_governor; } return ERR_PTR(-ENODEV); }


Nishanth Menon7080.46%150.00%
MyungJoo Ham1719.54%150.00%

static int devfreq_notify_transition(struct devfreq *devfreq, struct devfreq_freqs *freqs, unsigned int state) { if (!devfreq) return -EINVAL; switch (state) { case DEVFREQ_PRECHANGE: srcu_notifier_call_chain(&devfreq->transition_notifier_list, DEVFREQ_PRECHANGE, freqs); break; case DEVFREQ_POSTCHANGE: srcu_notifier_call_chain(&devfreq->transition_notifier_list, DEVFREQ_POSTCHANGE, freqs); break; default: return -EINVAL; } return 0; }


Chanwoo Choi75100.00%1100.00%

/* Load monitoring helper functions for governors use */ /** * update_devfreq() - Reevaluate the device and configure frequency. * @devfreq: the devfreq instance. * * Note: Lock devfreq->lock before calling update_devfreq * This function is exported for governors. */
int update_devfreq(struct devfreq *devfreq) { struct devfreq_freqs freqs; unsigned long freq, cur_freq; int err = 0; u32 flags = 0; if (!mutex_is_locked(&devfreq->lock)) { WARN(true, "devfreq->lock must be locked by the caller.\n"); return -EINVAL; } if (!devfreq->governor) return -EINVAL; /* Reevaluate the proper frequency */ err = devfreq->governor->get_target_freq(devfreq, &freq); if (err) return err; /* * Adjust the frequency with user freq and QoS. * * List from the highest priority * max_freq * min_freq */ if (devfreq->min_freq && freq < devfreq->min_freq) { freq = devfreq->min_freq; flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */ } if (devfreq->max_freq && freq > devfreq->max_freq) { freq = devfreq->max_freq; flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */ } if (devfreq->profile->get_cur_freq) devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq); else cur_freq = devfreq->previous_freq; freqs.old = cur_freq; = freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE); err = devfreq->profile->target(devfreq->dev.parent, &freq, flags); if (err) { = cur_freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); return err; } = freq; devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE); if (devfreq->profile->freq_table) if (devfreq_update_status(devfreq, freq)) dev_err(&devfreq->dev, "Couldn't update frequency transition information.\n"); devfreq->previous_freq = freq; return err; }


MyungJoo Ham18062.28%228.57%
Chanwoo Choi9332.18%228.57%
Jonghwa Lee113.81%114.29%
Nishanth Menon41.38%114.29%
Javi Merino10.35%114.29%

EXPORT_SYMBOL(update_devfreq); /** * devfreq_monitor() - Periodically poll devfreq objects. * @work: the work struct used to run devfreq_monitor periodically. * */
static void devfreq_monitor(struct work_struct *work) { int err; struct devfreq *devfreq = container_of(work, struct devfreq,; mutex_lock(&devfreq->lock); err = update_devfreq(devfreq); if (err) dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err); queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); mutex_unlock(&devfreq->lock); }


MyungJoo Ham5662.92%150.00%
Rajagopal Venkat3337.08%150.00%

/** * devfreq_monitor_start() - Start load monitoring of devfreq instance * @devfreq: the devfreq instance. * * Helper function for starting devfreq device load monitoing. By * default delayed work based monitoring is supported. Function * to be called from governor in response to DEVFREQ_GOV_START * event when device is added to devfreq framework. */
void devfreq_monitor_start(struct devfreq *devfreq) { INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor); if (devfreq->profile->polling_ms) queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); }


MyungJoo Ham3472.34%150.00%
Rajagopal Venkat1327.66%150.00%

EXPORT_SYMBOL(devfreq_monitor_start); /** * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance * @devfreq: the devfreq instance. * * Helper function to stop devfreq device load monitoing. Function * to be called from governor in response to DEVFREQ_GOV_STOP * event when device is removed from devfreq framework. */
void devfreq_monitor_stop(struct devfreq *devfreq) { cancel_delayed_work_sync(&devfreq->work); }


MyungJoo Ham1372.22%150.00%
Rajagopal Venkat527.78%150.00%

EXPORT_SYMBOL(devfreq_monitor_stop); /** * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance * @devfreq: the devfreq instance. * * Helper function to suspend devfreq device load monitoing. Function * to be called from governor in response to DEVFREQ_GOV_SUSPEND * event or when polling interval is set to zero. * * Note: Though this function is same as devfreq_monitor_stop(), * intentionally kept separate to provide hooks for collecting * transition statistics. */
void devfreq_monitor_suspend(struct devfreq *devfreq) { mutex_lock(&devfreq->lock); if (devfreq->stop_polling) { mutex_unlock(&devfreq->lock); return; } devfreq_update_status(devfreq, devfreq->previous_freq); devfreq->stop_polling = true; mutex_unlock(&devfreq->lock); cancel_delayed_work_sync(&devfreq->work); }


MyungJoo Ham4263.64%133.33%
Rajagopal Venkat2436.36%266.67%

EXPORT_SYMBOL(devfreq_monitor_suspend); /** * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance * @devfreq: the devfreq instance. * * Helper function to resume devfreq device load monitoing. Function * to be called from governor in response to DEVFREQ_GOV_RESUME * event or when polling interval is set to non-zero. */
void devfreq_monitor_resume(struct devfreq *devfreq) { unsigned long freq; mutex_lock(&devfreq->lock); if (!devfreq->stop_polling) goto out; if (!delayed_work_pending(&devfreq->work) && devfreq->profile->polling_ms) queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); devfreq->last_stat_updated = jiffies; devfreq->stop_polling = false; if (devfreq->profile->get_cur_freq && !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq)) devfreq->previous_freq = freq; out: mutex_unlock(&devfreq->lock); }


Rajagopal Venkat7360.33%266.67%
MyungJoo Ham4839.67%133.33%

EXPORT_SYMBOL(devfreq_monitor_resume); /** * devfreq_interval_update() - Update device devfreq monitoring interval * @devfreq: the devfreq instance. * @delay: new polling interval to be set. * * Helper function to set new load monitoring polling interval. Function * to be called from governor in response to DEVFREQ_GOV_INTERVAL event. */
void devfreq_interval_update(struct devfreq *devfreq, unsigned int *delay) { unsigned int cur_delay = devfreq->profile->polling_ms; unsigned int new_delay = *delay; mutex_lock(&devfreq->lock); devfreq->profile->polling_ms = new_delay; if (devfreq->stop_polling) goto out; /* if new delay is zero, stop polling */ if (!new_delay) { mutex_unlock(&devfreq->lock); cancel_delayed_work_sync(&devfreq->work); return; } /* if current delay is zero, start polling with new delay */ if (!cur_delay) { queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); goto out; } /* if current delay is greater than new delay, restart polling */ if (cur_delay > new_delay) { mutex_unlock(&devfreq->lock); cancel_delayed_work_sync(&devfreq->work); mutex_lock(&devfreq->lock); if (!devfreq->stop_polling) queue_delayed_work(devfreq_wq, &devfreq->work, msecs_to_jiffies(devfreq->profile->polling_ms)); } out: mutex_unlock(&devfreq->lock); }


Rajagopal Venkat10356.91%150.00%
MyungJoo Ham7843.09%150.00%

EXPORT_SYMBOL(devfreq_interval_update); /** * devfreq_notifier_call() - Notify that the device frequency requirements * has been changed out of devfreq framework. * @nb: the notifier_block (supposed to be devfreq->nb) * @type: not used * @devp: not used * * Called by a notifier that uses devfreq->nb. */
static int devfreq_notifier_call(struct notifier_block *nb, unsigned long type, void *devp) { struct devfreq *devfreq = container_of(nb, struct devfreq, nb); int ret; mutex_lock(&devfreq->lock); ret = update_devfreq(devfreq); mutex_unlock(&devfreq->lock); return ret; }


MyungJoo Ham3758.73%150.00%
Rajagopal Venkat2641.27%150.00%

/** * devfreq_dev_release() - Callback for struct device to release the device. * @dev: the devfreq device * * Remove devfreq from the list and release its resources. */
static void devfreq_dev_release(struct device *dev) { struct devfreq *devfreq = to_devfreq(dev); mutex_lock(&devfreq_list_lock); if (IS_ERR(find_device_devfreq(devfreq->dev.parent))) { mutex_unlock(&devfreq_list_lock); dev_warn(&devfreq->dev, "releasing devfreq which doesn't exist\n"); return; } list_del(&devfreq->node); mutex_unlock(&devfreq_list_lock); if (devfreq->governor) devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_STOP, NULL); if (devfreq->profile->exit) devfreq->profile->exit(devfreq->dev.parent); mutex_destroy(&devfreq->lock); kfree(devfreq); }


MyungJoo Ham6752.76%125.00%
Rajagopal Venkat4333.86%125.00%
Chanwoo Choi1310.24%125.00%
Nishanth Menon43.15%125.00%

/** * devfreq_add_device() - Add devfreq feature to the device * @dev: the device to add devfreq feature. * @profile: device-specific profile to run devfreq. * @governor_name: name of the policy to choose frequency. * @data: private data for the governor. The devfreq framework does not * touch this value. */
struct devfreq *devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, const char *governor_name, void *data) { struct devfreq *devfreq; struct devfreq_governor *governor; static atomic_t devfreq_no = ATOMIC_INIT(-1); int err = 0; if (!dev || !profile || !governor_name) { dev_err(dev, "%s: Invalid parameters.\n", __func__); return ERR_PTR(-EINVAL); } mutex_lock(&devfreq_list_lock); devfreq = find_device_devfreq(dev); mutex_unlock(&devfreq_list_lock); if (!IS_ERR(devfreq)) { dev_err(dev, "%s: Unable to create devfreq for the device.\n", __func__); err = -EINVAL; goto err_out; } devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL); if (!devfreq) { err = -ENOMEM; goto err_out; } mutex_init(&devfreq->lock); mutex_lock(&devfreq->lock); devfreq->dev.parent = dev; devfreq->dev.class = devfreq_class; devfreq->dev.release = devfreq_dev_release; devfreq->profile = profile; strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN); devfreq->previous_freq = profile->initial_freq; devfreq->last_status.current_frequency = profile->initial_freq; devfreq->data = data; devfreq->nb.notifier_call = devfreq_notifier_call; if (!devfreq->profile->max_state && !devfreq->profile->freq_table) { mutex_unlock(&devfreq->lock); devfreq_set_freq_table(devfreq); mutex_lock(&devfreq->lock); } dev_set_name(&devfreq->dev, "devfreq%d", atomic_inc_return(&devfreq_no)); err = device_register(&devfreq->dev); if (err) { mutex_unlock(&devfreq->lock); goto err_dev; } devfreq->trans_table = devm_kzalloc(&devfreq->dev, sizeof(unsigned int) * devfreq->profile->max_state * devfreq->profile->max_state, GFP_KERNEL); devfreq->time_in_state = devm_kzalloc(&devfreq->dev, sizeof(unsigned long) * devfreq->profile->max_state, GFP_KERNEL); devfreq->last_stat_updated = jiffies; srcu_init_notifier_head(&devfreq->transition_notifier_list); mutex_unlock(&devfreq->lock); mutex_lock(&devfreq_list_lock); list_add(&devfreq->node, &devfreq_list); governor = find_devfreq_governor(devfreq->governor_name); if (IS_ERR(governor)) { dev_err(dev, "%s: Unable to find governor for the device\n", __func__); err = PTR_ERR(governor); goto err_init; } devfreq->governor = governor; err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START, NULL); if (err) { dev_err(dev, "%s: Unable to start governor for the device\n", __func__); goto err_init; } mutex_unlock(&devfreq_list_lock); return devfreq; err_init: list_del(&devfreq->node); mutex_unlock(&devfreq_list_lock); device_unregister(&devfreq->dev); err_dev: if (devfreq) kfree(devfreq); err_out: return ERR_PTR(err); }


MyungJoo Ham30555.45%213.33%
Chanwoo Choi9517.27%640.00%
Jonghwa Lee5710.36%16.67%
Nishanth Menon346.18%16.67%
Rajagopal Venkat305.45%16.67%
Axel Lin183.27%213.33%
Lukasz Luba101.82%16.67%
Xiaolong Ye10.18%16.67%

EXPORT_SYMBOL(devfreq_add_device); /** * devfreq_remove_device() - Remove devfreq feature from a device. * @devfreq: the devfreq instance to be removed * * The opposite of devfreq_add_device(). */
int devfreq_remove_device(struct devfreq *devfreq) { if (!devfreq) return -EINVAL; device_unregister(&devfreq->dev); return 0; }


Rajagopal Venkat1653.33%133.33%
MyungJoo Ham826.67%133.33%
Chanwoo Choi620.00%133.33%

static int devm_devfreq_dev_match(struct device *dev, void *res, void *data) { struct devfreq **r = res; if (WARN_ON(!r || !*r)) return 0; return *r == data; }


Chanwoo Choi48100.00%1100.00%

static void devm_devfreq_dev_release(struct device *dev, void *res) { devfreq_remove_device(*(struct devfreq **)res); }


Chanwoo Choi27100.00%1100.00%

/** * devm_devfreq_add_device() - Resource-managed devfreq_add_device() * @dev: the device to add devfreq feature. * @profile: device-specific profile to run devfreq. * @governor_name: name of the policy to choose frequency. * @data: private data for the governor. The devfreq framework does not * touch this value. * * This function manages automatically the memory of devfreq device using device * resource management and simplify the free operation for memory of devfreq * device. */
struct devfreq *devm_devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile, const char *governor_name, void *data) { struct devfreq **ptr, *devfreq; ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL); if (!ptr) return ERR_PTR(-ENOMEM); devfreq = devfreq_add_device(dev, profile, governor_name, data); if (IS_ERR(devfreq)) { devres_free(ptr); return ERR_PTR(-ENOMEM); } *ptr = devfreq; devres_add(dev, ptr); return devfreq; }


Chanwoo Choi111100.00%1100.00%

EXPORT_SYMBOL(devm_devfreq_add_device); #ifdef CONFIG_OF /* * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree * @dev - instance to the given device * @index - index into list of devfreq * * return the instance of devfreq device */
struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index) { struct device_node *node; struct devfreq *devfreq; if (!dev) return ERR_PTR(-EINVAL); if (!dev->of_node) return ERR_PTR(-EINVAL); node = of_parse_phandle(dev->of_node, "devfreq", index); if (!node) return ERR_PTR(-ENODEV); mutex_lock(&devfreq_list_lock); list_for_each_entry(devfreq, &devfreq_list, node) { if (devfreq->dev.parent && devfreq->dev.parent->of_node == node) { mutex_unlock(&devfreq_list_lock); of_node_put(node); return devfreq; } } mutex_unlock(&devfreq_list_lock); of_node_put(node); return ERR_PTR(-EPROBE_DEFER); }


Chanwoo Choi13493.06%150.00%
Peter Chen106.94%150.00%

struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev, int index) { return ERR_PTR(-ENODEV); }


Chanwoo Choi22100.00%1100.00%

#endif /* CONFIG_OF */ EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle); /** * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device() * @dev: the device to add devfreq feature. * @devfreq: the devfreq instance to be removed */
void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq) { WARN_ON(devres_release(dev, devm_devfreq_dev_release, devm_devfreq_dev_match, devfreq)); }


Chanwoo Choi29100.00%1100.00%

EXPORT_SYMBOL(devm_devfreq_remove_device); /** * devfreq_suspend_device() - Suspend devfreq of a device. * @devfreq: the devfreq instance to be suspended * * This function is intended to be called by the pm callbacks * (e.g., runtime_suspend, suspend) of the device driver that * holds the devfreq. */
int devfreq_suspend_device(struct devfreq *devfreq) { if (!devfreq) return -EINVAL; if (!devfreq->governor) return 0; return devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_SUSPEND, NULL); }


Rajagopal Venkat3376.74%150.00%
Nishanth Menon1023.26%150.00%

EXPORT_SYMBOL(devfreq_suspend_device); /** * devfreq_resume_device() - Resume devfreq of a device. * @devfreq: the devfreq instance to be resumed * * This function is intended to be called by the pm callbacks * (e.g., runtime_resume, resume) of the device driver that * holds the devfreq. */
int devfreq_resume_device(struct devfreq *devfreq) { if (!devfreq) return -EINVAL; if (!devfreq->governor) return 0; return devfreq