diff options
Diffstat (limited to 'drivers/devfreq/devfreq.c')
| -rw-r--r-- | drivers/devfreq/devfreq.c | 1222 |
1 files changed, 1222 insertions, 0 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c new file mode 100644 index 00000000000..9f90369dd6b --- /dev/null +++ b/drivers/devfreq/devfreq.c @@ -0,0 +1,1222 @@ +/* + * 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. + */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/errno.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/module.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 "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 (unlikely(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); +} + +/** + * 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; +} + +/** + * devfreq_update_status() - Update statistics of devfreq behavior + * @devfreq: the devfreq instance + * @freq: the update target frequency + */ +static int devfreq_update_status(struct devfreq *devfreq, unsigned long freq) +{ + int lev, prev_lev, ret = 0; + unsigned long cur_time; + + cur_time = jiffies; + + 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; +} + +/** + * 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 (unlikely(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); +} + +/* 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) +{ + unsigned long 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 freuqency with user freq and QoS. + * + * List from the highest proiority + * max_freq (probably called by thermal when it's too hot) + * 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 */ + } + + err = devfreq->profile->target(devfreq->dev.parent, &freq, flags); + if (err) + return err; + + 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; +} +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, work.work); + + 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); +} + +/** + * 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)); +} +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); +} +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); +} +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); +} +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); +} +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; +} + +/** + * _remove_devfreq() - Remove devfreq from the list and release its resources. + * @devfreq: the devfreq struct + * @skip: skip calling device_unregister(). + */ +static void _remove_devfreq(struct devfreq *devfreq) +{ + 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); +} + +/** + * devfreq_dev_release() - Callback for struct device to release the device. + * @dev: the devfreq device + * + * This calls _remove_devfreq() if _remove_devfreq() is not called. + */ +static void devfreq_dev_release(struct device *dev) +{ + struct devfreq *devfreq = to_devfreq(dev); + + _remove_devfreq(devfreq); +} + +/** + * 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; + 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. It already has one.\n", __func__); + err = -EINVAL; + goto err_out; + } + + devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL); + if (!devfreq) { + dev_err(dev, "%s: Unable to create devfreq for the device\n", + __func__); + 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->data = data; + devfreq->nb.notifier_call = devfreq_notifier_call; + + devfreq->trans_table = devm_kzalloc(dev, sizeof(unsigned int) * + devfreq->profile->max_state * + devfreq->profile->max_state, + GFP_KERNEL); + devfreq->time_in_state = devm_kzalloc(dev, sizeof(unsigned int) * + devfreq->profile->max_state, + GFP_KERNEL); + devfreq->last_stat_updated = jiffies; + + dev_set_name(&devfreq->dev, "%s", dev_name(dev)); + err = device_register(&devfreq->dev); + if (err) { + put_device(&devfreq->dev); + mutex_unlock(&devfreq->lock); + goto err_dev; + } + + 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)) + devfreq->governor = governor; + if (devfreq->governor) + err = devfreq->governor->event_handler(devfreq, + DEVFREQ_GOV_START, NULL); + mutex_unlock(&devfreq_list_lock); + if (err) { + dev_err(dev, "%s: Unable to start governor for the device\n", + __func__); + goto err_init; + } + + return devfreq; + +err_init: + list_del(&devfreq->node); + device_unregister(&devfreq->dev); +err_dev: + kfree(devfreq); +err_out: + return ERR_PTR(err); +} +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); + put_device(&devfreq->dev); + + return 0; +} +EXPORT_SYMBOL(devfreq_remove_device); + +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; +} + +static void devm_devfreq_dev_release(struct device *dev, void *res) +{ + devfreq_remove_device(*(struct devfreq **)res); +} + +/** + * 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; +} +EXPORT_SYMBOL(devm_devfreq_add_device); + +/** + * 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)); +} +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); +} +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->governor->event_handler(devfreq, + DEVFREQ_GOV_RESUME, NULL); +} +EXPORT_SYMBOL(devfreq_resume_device); + +/** + * devfreq_add_governor() - Add devfreq governor + * @governor: the devfreq governor to be added + */ +int devfreq_add_governor(struct devfreq_governor *governor) +{ + struct devfreq_governor *g; + struct devfreq *devfreq; + int err = 0; + + if (!governor) { + pr_err("%s: Invalid parameters.\n", __func__); + return -EINVAL; + } + + mutex_lock(&devfreq_list_lock); + g = find_devfreq_governor(governor->name); + if (!IS_ERR(g)) { + pr_err("%s: governor %s already registered\n", __func__, + g->name); + err = -EINVAL; + goto err_out; + } + + list_add(&governor->node, &devfreq_governor_list); + + list_for_each_entry(devfreq, &devfreq_list, node) { + int ret = 0; + struct device *dev = devfreq->dev.parent; + + if (!strncmp(devfreq->governor_name, governor->name, + DEVFREQ_NAME_LEN)) { + /* The following should never occur */ + if (devfreq->governor) { + dev_warn(dev, + "%s: Governor %s already present\n", + __func__, devfreq->governor->name); + ret = devfreq->governor->event_handler(devfreq, + DEVFREQ_GOV_STOP, NULL); + if (ret) { + dev_warn(dev, + "%s: Governor %s stop = %d\n", + __func__, + devfreq->governor->name, ret); + } + /* Fall through */ + } + devfreq->governor = governor; + ret = devfreq->governor->event_handler(devfreq, + DEVFREQ_GOV_START, NULL); + if (ret) { + dev_warn(dev, "%s: Governor %s start=%d\n", + __func__, devfreq->governor->name, + ret); + } + } + } + +err_out: + mutex_unlock(&devfreq_list_lock); + + return err; +} +EXPORT_SYMBOL(devfreq_add_governor); + +/** + * devfreq_remove_device() - Remove devfreq feature from a device. + * @governor: the devfreq governor to be removed + */ +int devfreq_remove_governor(struct devfreq_governor *governor) +{ + struct devfreq_governor *g; + struct devfreq *devfreq; + int err = 0; + + if (!governor) { + pr_err("%s: Invalid parameters.\n", __func__); + return -EINVAL; + } + + mutex_lock(&devfreq_list_lock); + g = find_devfreq_governor(governor->name); + if (IS_ERR(g)) { + pr_err("%s: governor %s not registered\n", __func__, + governor->name); + err = PTR_ERR(g); + goto err_out; + } + list_for_each_entry(devfreq, &devfreq_list, node) { + int ret; + struct device *dev = devfreq->dev.parent; + + if (!strncmp(devfreq->governor_name, governor->name, + DEVFREQ_NAME_LEN)) { + /* we should have a devfreq governor! */ + if (!devfreq->governor) { + dev_warn(dev, "%s: Governor %s NOT present\n", + __func__, governor->name); + continue; + /* Fall through */ + } + ret = devfreq->governor->event_handler(devfreq, + DEVFREQ_GOV_STOP, NULL); + if (ret) { + dev_warn(dev, "%s: Governor %s stop=%d\n", + __func__, devfreq->governor->name, + ret); + } + devfreq->governor = NULL; + } + } + + list_del(&governor->node); +err_out: + mutex_unlock(&devfreq_list_lock); + + return err; +} +EXPORT_SYMBOL(devfreq_remove_governor); + +static ssize_t governor_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + if (!to_devfreq(dev)->governor) + return -EINVAL; + + return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name); +} + +static ssize_t governor_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + int ret; + char str_governor[DEVFREQ_NAME_LEN + 1]; + struct devfreq_governor *governor; + + ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor); + if (ret != 1) + return -EINVAL; + + mutex_lock(&devfreq_list_lock); + governor = find_devfreq_governor(str_governor); + if (IS_ERR(governor)) { + ret = PTR_ERR(governor); + goto out; + } + if (df->governor == governor) + goto out; + + if (df->governor) { + ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL); + if (ret) { + dev_warn(dev, "%s: Governor %s not stopped(%d)\n", + __func__, df->governor->name, ret); + goto out; + } + } + df->governor = governor; + strncpy(df->governor_name, governor->name, DEVFREQ_NAME_LEN); + ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL); + if (ret) + dev_warn(dev, "%s: Governor %s not started(%d)\n", + __func__, df->governor->name, ret); +out: + mutex_unlock(&devfreq_list_lock); + + if (!ret) + ret = count; + return ret; +} +static DEVICE_ATTR_RW(governor); + +static ssize_t available_governors_show(struct device *d, + struct device_attribute *attr, + char *buf) +{ + struct devfreq_governor *tmp_governor; + ssize_t count = 0; + + mutex_lock(&devfreq_list_lock); + list_for_each_entry(tmp_governor, &devfreq_governor_list, node) + count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), + "%s ", tmp_governor->name); + mutex_unlock(&devfreq_list_lock); + + /* Truncate the trailing space */ + if (count) + count--; + + count += sprintf(&buf[count], "\n"); + + return count; +} +static DEVICE_ATTR_RO(available_governors); + +static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + unsigned long freq; + struct devfreq *devfreq = to_devfreq(dev); + + if (devfreq->profile->get_cur_freq && + !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq)) + return sprintf(buf, "%lu\n", freq); + + return sprintf(buf, "%lu\n", devfreq->previous_freq); +} +static DEVICE_ATTR_RO(cur_freq); + +static ssize_t target_freq_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq); +} +static DEVICE_ATTR_RO(target_freq); + +static ssize_t polling_interval_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms); +} + +static ssize_t polling_interval_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned int value; + int ret; + + if (!df->governor) + return -EINVAL; + + ret = sscanf(buf, "%u", &value); + if (ret != 1) + return -EINVAL; + + df->governor->event_handler(df, DEVFREQ_GOV_INTERVAL, &value); + ret = count; + + return ret; +} +static DEVICE_ATTR_RW(polling_interval); + +static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long value; + int ret; + unsigned long max; + + ret = sscanf(buf, "%lu", &value); + if (ret != 1) + return -EINVAL; + + mutex_lock(&df->lock); + max = df->max_freq; + if (value && max && value > max) { + ret = -EINVAL; + goto unlock; + } + + df->min_freq = value; + update_devfreq(df); + ret = count; +unlock: + mutex_unlock(&df->lock); + return ret; +} + +static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%lu\n", to_devfreq(dev)->min_freq); +} + +static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned long value; + int ret; + unsigned long min; + + ret = sscanf(buf, "%lu", &value); + if (ret != 1) + return -EINVAL; + + mutex_lock(&df->lock); + min = df->min_freq; + if (value && min && value < min) { + ret = -EINVAL; + goto unlock; + } + + df->max_freq = value; + update_devfreq(df); + ret = count; +unlock: + mutex_unlock(&df->lock); + return ret; +} +static DEVICE_ATTR_RW(min_freq); + +static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + return sprintf(buf, "%lu\n", to_devfreq(dev)->max_freq); +} +static DEVICE_ATTR_RW(max_freq); + +static ssize_t available_frequencies_show(struct device *d, + struct device_attribute *attr, + char *buf) +{ + struct devfreq *df = to_devfreq(d); + struct device *dev = df->dev.parent; + struct dev_pm_opp *opp; + ssize_t count = 0; + unsigned long freq = 0; + + rcu_read_lock(); + do { + opp = dev_pm_opp_find_freq_ceil(dev, &freq); + if (IS_ERR(opp)) + break; + + count += scnprintf(&buf[count], (PAGE_SIZE - count - 2), + "%lu ", freq); + freq++; + } while (1); + rcu_read_unlock(); + + /* Truncate the trailing space */ + if (count) + count--; + + count += sprintf(&buf[count], "\n"); + + return count; +} +static DEVICE_ATTR_RO(available_frequencies); + +static ssize_t trans_stat_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct devfreq *devfreq = to_devfreq(dev); + ssize_t len; + int i, j; + unsigned int max_state = devfreq->profile->max_state; + + if (!devfreq->stop_polling && + devfreq_update_status(devfreq, devfreq->previous_freq)) + return 0; + + len = sprintf(buf, " From : To\n"); + len += sprintf(buf + len, " :"); + for (i = 0; i < max_state; i++) + len += sprintf(buf + len, "%8u", + devfreq->profile->freq_table[i]); + + len += sprintf(buf + len, " time(ms)\n"); + + for (i = 0; i < max_state; i++) { + if (devfreq->profile->freq_table[i] + == devfreq->previous_freq) { + len += sprintf(buf + len, "*"); + } else { + len += sprintf(buf + len, " "); + } + len += sprintf(buf + len, "%8u:", + devfreq->profile->freq_table[i]); + for (j = 0; j < max_state; j++) + len += sprintf(buf + len, "%8u", + devfreq->trans_table[(i * max_state) + j]); + len += sprintf(buf + len, "%10u\n", + jiffies_to_msecs(devfreq->time_in_state[i])); + } + + len += sprintf(buf + len, "Total transition : %u\n", + devfreq->total_trans); + return len; +} +static DEVICE_ATTR_RO(trans_stat); + +static struct attribute *devfreq_attrs[] = { + &dev_attr_governor.attr, + &dev_attr_available_governors.attr, + &dev_attr_cur_freq.attr, + &dev_attr_available_frequencies.attr, + &dev_attr_target_freq.attr, + &dev_attr_polling_interval.attr, + &dev_attr_min_freq.attr, + &dev_attr_max_freq.attr, + &dev_attr_trans_stat.attr, + NULL, +}; +ATTRIBUTE_GROUPS(devfreq); + +static int __init devfreq_init(void) +{ + devfreq_class = class_create(THIS_MODULE, "devfreq"); + if (IS_ERR(devfreq_class)) { + pr_err("%s: couldn't create class\n", __FILE__); + return PTR_ERR(devfreq_class); + } + + devfreq_wq = create_freezable_workqueue("devfreq_wq"); + if (!devfreq_wq) { + class_destroy(devfreq_class); + pr_err("%s: couldn't create workqueue\n", __FILE__); + return -ENOMEM; + } + devfreq_class->dev_groups = devfreq_groups; + + return 0; +} +subsys_initcall(devfreq_init); + +static void __exit devfreq_exit(void) +{ + class_destroy(devfreq_class); + destroy_workqueue(devfreq_wq); +} +module_exit(devfreq_exit); + +/* + * The followings are helper functions for devfreq user device drivers with + * OPP framework. + */ + +/** + * devfreq_recommended_opp() - Helper function to get proper OPP for the + * freq value given to target callback. + * @dev: The devfreq user device. (parent of devfreq) + * @freq: The frequency given to target function + * @flags: Flags handed from devfreq framework. + * + * Locking: This function must be called under rcu_read_lock(). opp is a rcu + * protected pointer. The reason for the same is that the opp pointer which is + * returned will remain valid for use with opp_get_{voltage, freq} only while + * under the locked area. The pointer returned must be used prior to unlocking + * with rcu_read_unlock() to maintain the integrity of the pointer. + */ +struct dev_pm_opp *devfreq_recommended_opp(struct device *dev, + unsigned long *freq, + u32 flags) +{ + struct dev_pm_opp *opp; + + if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) { + /* The freq is an upper bound. opp should be lower */ + opp = dev_pm_opp_find_freq_floor(dev, freq); + + /* If not available, use the closest opp */ + if (opp == ERR_PTR(-ERANGE)) + opp = dev_pm_opp_find_freq_ceil(dev, freq); + } else { + /* The freq is an lower bound. opp should be higher */ + opp = dev_pm_opp_find_freq_ceil(dev, freq); + + /* If not available, use the closest opp */ + if (opp == ERR_PTR(-ERANGE)) + opp = dev_pm_opp_find_freq_floor(dev, freq); + } + + return opp; +} + +/** + * devfreq_register_opp_notifier() - Helper function to get devfreq notified + * for any changes in the OPP availability + * changes + * @dev: The devfreq user device. (parent of devfreq) + * @devfreq: The devfreq object. + */ +int devfreq_register_opp_notifier(struct device *dev, struct devfreq *devfreq) +{ + struct srcu_notifier_head *nh; + int ret = 0; + + rcu_read_lock(); + nh = dev_pm_opp_get_notifier(dev); + if (IS_ERR(nh)) + ret = PTR_ERR(nh); + rcu_read_unlock(); + if (!ret) + ret = srcu_notifier_chain_register(nh, &devfreq->nb); + + return ret; +} + +/** + * devfreq_unregister_opp_notifier() - Helper function to stop getting devfreq + * notified for any changes in the OPP + * availability changes anymore. + * @dev: The devfreq user device. (parent of devfreq) + * @devfreq: The devfreq object. + * + * At exit() callback of devfreq_dev_profile, this must be included if + * devfreq_recommended_opp is used. + */ +int devfreq_unregister_opp_notifier(struct device *dev, struct devfreq *devfreq) +{ + struct srcu_notifier_head *nh; + int ret = 0; + + rcu_read_lock(); + nh = dev_pm_opp_get_notifier(dev); + if (IS_ERR(nh)) + ret = PTR_ERR(nh); + rcu_read_unlock(); + if (!ret) + ret = srcu_notifier_chain_unregister(nh, &devfreq->nb); + + return ret; +} + +static void devm_devfreq_opp_release(struct device *dev, void *res) +{ + devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res); +} + +/** + * devm_ devfreq_register_opp_notifier() + * - Resource-managed devfreq_register_opp_notifier() + * @dev: The devfreq user device. (parent of devfreq) + * @devfreq: The devfreq object. + */ +int devm_devfreq_register_opp_notifier(struct device *dev, + struct devfreq *devfreq) +{ + struct devfreq **ptr; + int ret; + + ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL); + if (!ptr) + return -ENOMEM; + + ret = devfreq_register_opp_notifier(dev, devfreq); + if (ret) { + devres_free(ptr); + return ret; + } + + *ptr = devfreq; + devres_add(dev, ptr); + + return 0; +} +EXPORT_SYMBOL(devm_devfreq_register_opp_notifier); + +/** + * devm_devfreq_unregister_opp_notifier() + * - Resource-managed devfreq_unregister_opp_notifier() + * @dev: The devfreq user device. (parent of devfreq) + * @devfreq: The devfreq object. + */ +void devm_devfreq_unregister_opp_notifier(struct device *dev, + struct devfreq *devfreq) +{ + WARN_ON(devres_release(dev, devm_devfreq_opp_release, + devm_devfreq_dev_match, devfreq)); +} +EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier); + +MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); +MODULE_DESCRIPTION("devfreq class support"); +MODULE_LICENSE("GPL"); |