diff options
Diffstat (limited to 'drivers/devfreq')
| -rw-r--r-- | drivers/devfreq/Kconfig | 75 | ||||
| -rw-r--r-- | drivers/devfreq/Makefile | 5 | ||||
| -rw-r--r-- | drivers/devfreq/devfreq.c | 601 | ||||
| -rw-r--r-- | drivers/devfreq/governor.h | 24 | ||||
| -rw-r--r-- | drivers/devfreq/governor_performance.c | 29 | ||||
| -rw-r--r-- | drivers/devfreq/governor_powersave.c | 29 | ||||
| -rw-r--r-- | drivers/devfreq/governor_simpleondemand.c | 88 | ||||
| -rw-r--r-- | drivers/devfreq/governor_userspace.c | 116 |
8 files changed, 967 insertions, 0 deletions
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig new file mode 100644 index 00000000000..643b055ed3c --- /dev/null +++ b/drivers/devfreq/Kconfig @@ -0,0 +1,75 @@ +config ARCH_HAS_DEVFREQ + bool + depends on ARCH_HAS_OPP + help + Denotes that the architecture supports DEVFREQ. If the architecture + supports multiple OPP entries per device and the frequency of the + devices with OPPs may be altered dynamically, the architecture + supports DEVFREQ. + +menuconfig PM_DEVFREQ + bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) support" + depends on PM_OPP && ARCH_HAS_DEVFREQ + help + With OPP support, a device may have a list of frequencies and + voltages available. DEVFREQ, a generic DVFS framework can be + registered for a device with OPP support in order to let the + governor provided to DEVFREQ choose an operating frequency + based on the OPP's list and the policy given with DEVFREQ. + + Each device may have its own governor and policy. DEVFREQ can + reevaluate the device state periodically and/or based on the + OPP list changes (each frequency/voltage pair in OPP may be + disabled or enabled). + + Like some CPUs with CPUFREQ, a device may have multiple clocks. + However, because the clock frequencies of a single device are + determined by the single device's state, an instance of DEVFREQ + is attached to a single device and returns a "representative" + clock frequency from the OPP of the device, which is also attached + to a device by 1-to-1. The device registering DEVFREQ takes the + responsiblity to "interpret" the frequency listed in OPP and + to set its every clock accordingly with the "target" callback + given to DEVFREQ. + +if PM_DEVFREQ + +comment "DEVFREQ Governors" + +config DEVFREQ_GOV_SIMPLE_ONDEMAND + bool "Simple Ondemand" + help + Chooses frequency based on the recent load on the device. Works + similar as ONDEMAND governor of CPUFREQ does. A device with + Simple-Ondemand should be able to provide busy/total counter + values that imply the usage rate. A device may provide tuned + values to the governor with data field at devfreq_add_device(). + +config DEVFREQ_GOV_PERFORMANCE + bool "Performance" + help + Sets the frequency at the maximum available frequency. + This governor always returns UINT_MAX as frequency so that + the DEVFREQ framework returns the highest frequency available + at any time. + +config DEVFREQ_GOV_POWERSAVE + bool "Powersave" + help + Sets the frequency at the minimum available frequency. + This governor always returns 0 as frequency so that + the DEVFREQ framework returns the lowest frequency available + at any time. + +config DEVFREQ_GOV_USERSPACE + bool "Userspace" + help + Sets the frequency at the user specified one. + This governor returns the user configured frequency if there + has been an input to /sys/devices/.../power/devfreq_set_freq. + Otherwise, the governor does not change the frequnecy + given at the initialization. + +comment "DEVFREQ Drivers" + +endif # PM_DEVFREQ diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile new file mode 100644 index 00000000000..4564a89e970 --- /dev/null +++ b/drivers/devfreq/Makefile @@ -0,0 +1,5 @@ +obj-$(CONFIG_PM_DEVFREQ) += devfreq.o +obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) += governor_simpleondemand.o +obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o +obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o +obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c new file mode 100644 index 00000000000..5d15b812377 --- /dev/null +++ b/drivers/devfreq/devfreq.c @@ -0,0 +1,601 @@ +/* + * 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/slab.h> +#include <linux/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" + +struct class *devfreq_class; + +/* + * devfreq_work periodically monitors every registered device. + * The minimum polling interval is one jiffy. The polling interval is + * determined by the minimum polling period among all polling devfreq + * devices. The resolution of polling interval is one jiffy. + */ +static bool polling; +static struct workqueue_struct *devfreq_wq; +static struct delayed_work devfreq_work; + +/* wait removing if this is to be removed */ +static struct devfreq *wait_remove_device; + +/* 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); +} + +/** + * 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; + + if (!mutex_is_locked(&devfreq->lock)) { + WARN(true, "devfreq->lock must be locked by the caller.\n"); + return -EINVAL; + } + + /* Reevaluate the proper frequency */ + err = devfreq->governor->get_target_freq(devfreq, &freq); + if (err) + return err; + + err = devfreq->profile->target(devfreq->dev.parent, &freq); + if (err) + return err; + + devfreq->previous_freq = freq; + return err; +} + +/** + * 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 device. + * @devfreq: the devfreq struct + * @skip: skip calling device_unregister(). + * + * Note that the caller should lock devfreq->lock before calling + * this. _remove_devfreq() will unlock it and free devfreq + * internally. devfreq_list_lock should be locked by the caller + * as well (not relased at return) + * + * Lock usage: + * devfreq->lock: locked before call. + * unlocked at return (and freed) + * devfreq_list_lock: locked before call. + * kept locked at return. + * if devfreq is centrally polled. + * + * Freed memory: + * devfreq + */ +static void _remove_devfreq(struct devfreq *devfreq, bool skip) +{ + if (!mutex_is_locked(&devfreq->lock)) { + WARN(true, "devfreq->lock must be locked by the caller.\n"); + return; + } + if (!devfreq->governor->no_central_polling && + !mutex_is_locked(&devfreq_list_lock)) { + WARN(true, "devfreq_list_lock must be locked by the caller.\n"); + return; + } + + if (devfreq->being_removed) + return; + + devfreq->being_removed = true; + + if (devfreq->profile->exit) + devfreq->profile->exit(devfreq->dev.parent); + + if (devfreq->governor->exit) + devfreq->governor->exit(devfreq); + + if (!skip && get_device(&devfreq->dev)) { + device_unregister(&devfreq->dev); + put_device(&devfreq->dev); + } + + if (!devfreq->governor->no_central_polling) + list_del(&devfreq->node); + + mutex_unlock(&devfreq->lock); + 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. + * Note that devfreq_dev_release() could be called by _remove_devfreq() as + * well as by others unregistering the device. + */ +static void devfreq_dev_release(struct device *dev) +{ + struct devfreq *devfreq = to_devfreq(dev); + bool central_polling = !devfreq->governor->no_central_polling; + + /* + * If devfreq_dev_release() was called by device_unregister() of + * _remove_devfreq(), we cannot mutex_lock(&devfreq->lock) and + * being_removed is already set. This also partially checks the case + * where devfreq_dev_release() is called from a thread other than + * the one called _remove_devfreq(); however, this case is + * dealt completely with another following being_removed check. + * + * Because being_removed is never being + * unset, we do not need to worry about race conditions on + * being_removed. + */ + if (devfreq->being_removed) + return; + + if (central_polling) + mutex_lock(&devfreq_list_lock); + + mutex_lock(&devfreq->lock); + + /* + * Check being_removed flag again for the case where + * devfreq_dev_release() was called in a thread other than the one + * possibly called _remove_devfreq(). + */ + if (devfreq->being_removed) { + mutex_unlock(&devfreq->lock); + goto out; + } + + /* devfreq->lock is unlocked and removed in _removed_devfreq() */ + _remove_devfreq(devfreq, true); + +out: + if (central_polling) + mutex_unlock(&devfreq_list_lock); +} + +/** + * devfreq_monitor() - Periodically poll devfreq objects. + * @work: the work struct used to run devfreq_monitor periodically. + * + */ +static void devfreq_monitor(struct work_struct *work) +{ + static unsigned long last_polled_at; + struct devfreq *devfreq, *tmp; + int error; + unsigned long jiffies_passed; + unsigned long next_jiffies = ULONG_MAX, now = jiffies; + struct device *dev; + + /* Initially last_polled_at = 0, polling every device at bootup */ + jiffies_passed = now - last_polled_at; + last_polled_at = now; + if (jiffies_passed == 0) + jiffies_passed = 1; + + mutex_lock(&devfreq_list_lock); + list_for_each_entry_safe(devfreq, tmp, &devfreq_list, node) { + mutex_lock(&devfreq->lock); + dev = devfreq->dev.parent; + + /* Do not remove tmp for a while */ + wait_remove_device = tmp; + + if (devfreq->governor->no_central_polling || + devfreq->next_polling == 0) { + mutex_unlock(&devfreq->lock); + continue; + } + mutex_unlock(&devfreq_list_lock); + + /* + * Reduce more next_polling if devfreq_wq took an extra + * delay. (i.e., CPU has been idled.) + */ + if (devfreq->next_polling <= jiffies_passed) { + error = update_devfreq(devfreq); + + /* Remove a devfreq with an error. */ + if (error && error != -EAGAIN) { + + dev_err(dev, "Due to update_devfreq error(%d), devfreq(%s) is removed from the device\n", + error, devfreq->governor->name); + + /* + * Unlock devfreq before locking the list + * in order to avoid deadlock with + * find_device_devfreq or others + */ + mutex_unlock(&devfreq->lock); + mutex_lock(&devfreq_list_lock); + /* Check if devfreq is already removed */ + if (IS_ERR(find_device_devfreq(dev))) + continue; + mutex_lock(&devfreq->lock); + /* This unlocks devfreq->lock and free it */ + _remove_devfreq(devfreq, false); + continue; + } + devfreq->next_polling = devfreq->polling_jiffies; + } else { + devfreq->next_polling -= jiffies_passed; + } + + if (devfreq->next_polling) + next_jiffies = (next_jiffies > devfreq->next_polling) ? + devfreq->next_polling : next_jiffies; + + mutex_unlock(&devfreq->lock); + mutex_lock(&devfreq_list_lock); + } + wait_remove_device = NULL; + mutex_unlock(&devfreq_list_lock); + + if (next_jiffies > 0 && next_jiffies < ULONG_MAX) { + polling = true; + queue_delayed_work(devfreq_wq, &devfreq_work, next_jiffies); + } else { + polling = false; + } +} + +/** + * devfreq_add_device() - Add devfreq feature to the device + * @dev: the device to add devfreq feature. + * @profile: device-specific profile to run devfreq. + * @governor: 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 struct devfreq_governor *governor, + void *data) +{ + struct devfreq *devfreq; + int err = 0; + + if (!dev || !profile || !governor) { + dev_err(dev, "%s: Invalid parameters.\n", __func__); + return ERR_PTR(-EINVAL); + } + + + if (!governor->no_central_polling) { + 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 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 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; + devfreq->governor = governor; + devfreq->previous_freq = profile->initial_freq; + devfreq->data = data; + devfreq->next_polling = devfreq->polling_jiffies + = msecs_to_jiffies(devfreq->profile->polling_ms); + devfreq->nb.notifier_call = devfreq_notifier_call; + + dev_set_name(&devfreq->dev, dev_name(dev)); + err = device_register(&devfreq->dev); + if (err) { + put_device(&devfreq->dev); + goto err_dev; + } + + if (governor->init) + err = governor->init(devfreq); + if (err) + goto err_init; + + mutex_unlock(&devfreq->lock); + + if (governor->no_central_polling) + goto out; + + mutex_lock(&devfreq_list_lock); + + list_add(&devfreq->node, &devfreq_list); + + if (devfreq_wq && devfreq->next_polling && !polling) { + polling = true; + queue_delayed_work(devfreq_wq, &devfreq_work, + devfreq->next_polling); + } + mutex_unlock(&devfreq_list_lock); + goto out; +err_init: + device_unregister(&devfreq->dev); +err_dev: + mutex_unlock(&devfreq->lock); + kfree(devfreq); +out: + if (err) + return ERR_PTR(err); + else + return devfreq; +} + +/** + * devfreq_remove_device() - Remove devfreq feature from a device. + * @devfreq the devfreq instance to be removed + */ +int devfreq_remove_device(struct devfreq *devfreq) +{ + if (!devfreq) + return -EINVAL; + + if (!devfreq->governor->no_central_polling) { + mutex_lock(&devfreq_list_lock); + while (wait_remove_device == devfreq) { + mutex_unlock(&devfreq_list_lock); + schedule(); + mutex_lock(&devfreq_list_lock); + } + } + + mutex_lock(&devfreq->lock); + _remove_devfreq(devfreq, false); /* it unlocks devfreq->lock */ + + if (!devfreq->governor->no_central_polling) + mutex_unlock(&devfreq_list_lock); + + return 0; +} + +static ssize_t show_governor(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%s\n", to_devfreq(dev)->governor->name); +} + +static ssize_t show_freq(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%lu\n", to_devfreq(dev)->previous_freq); +} + +static ssize_t show_polling_interval(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", to_devfreq(dev)->profile->polling_ms); +} + +static ssize_t store_polling_interval(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *df = to_devfreq(dev); + unsigned int value; + int ret; + + ret = sscanf(buf, "%u", &value); + if (ret != 1) + goto out; + + mutex_lock(&df->lock); + df->profile->polling_ms = value; + df->next_polling = df->polling_jiffies + = msecs_to_jiffies(value); + mutex_unlock(&df->lock); + + ret = count; + + if (df->governor->no_central_polling) + goto out; + + mutex_lock(&devfreq_list_lock); + if (df->next_polling > 0 && !polling) { + polling = true; + queue_delayed_work(devfreq_wq, &devfreq_work, + df->next_polling); + } + mutex_unlock(&devfreq_list_lock); +out: + return ret; +} + +static ssize_t show_central_polling(struct device *dev, + struct device_attribute *attr, char *buf) +{ + return sprintf(buf, "%d\n", + !to_devfreq(dev)->governor->no_central_polling); +} + +static struct device_attribute devfreq_attrs[] = { + __ATTR(governor, S_IRUGO, show_governor, NULL), + __ATTR(cur_freq, S_IRUGO, show_freq, NULL), + __ATTR(central_polling, S_IRUGO, show_central_polling, NULL), + __ATTR(polling_interval, S_IRUGO | S_IWUSR, show_polling_interval, + store_polling_interval), + { }, +}; + +/** + * devfreq_start_polling() - Initialize data structure for devfreq framework and + * start polling registered devfreq devices. + */ +static int __init devfreq_start_polling(void) +{ + mutex_lock(&devfreq_list_lock); + polling = false; + devfreq_wq = create_freezable_workqueue("devfreq_wq"); + INIT_DELAYED_WORK_DEFERRABLE(&devfreq_work, devfreq_monitor); + mutex_unlock(&devfreq_list_lock); + + devfreq_monitor(&devfreq_work.work); + return 0; +} +late_initcall(devfreq_start_polling); + +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_class->dev_attrs = devfreq_attrs; + return 0; +} +subsys_initcall(devfreq_init); + +static void __exit devfreq_exit(void) +{ + class_destroy(devfreq_class); +} +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 + * + */ +struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq) +{ + struct opp *opp = opp_find_freq_ceil(dev, freq); + + if (opp == ERR_PTR(-ENODEV)) + opp = 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 = opp_get_notifier(dev); + + if (IS_ERR(nh)) + return PTR_ERR(nh); + return srcu_notifier_chain_register(nh, &devfreq->nb); +} + +/** + * 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 = opp_get_notifier(dev); + + if (IS_ERR(nh)) + return PTR_ERR(nh); + return srcu_notifier_chain_unregister(nh, &devfreq->nb); +} + +MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>"); +MODULE_DESCRIPTION("devfreq class support"); +MODULE_LICENSE("GPL"); diff --git a/drivers/devfreq/governor.h b/drivers/devfreq/governor.h new file mode 100644 index 00000000000..ea7f13c58de --- /dev/null +++ b/drivers/devfreq/governor.h @@ -0,0 +1,24 @@ +/* + * governor.h - internal header for devfreq governors. + * + * 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. + * + * This header is for devfreq governors in drivers/devfreq/ + */ + +#ifndef _GOVERNOR_H +#define _GOVERNOR_H + +#include <linux/devfreq.h> + +#define to_devfreq(DEV) container_of((DEV), struct devfreq, dev) + +/* Caution: devfreq->lock must be locked before calling update_devfreq */ +extern int update_devfreq(struct devfreq *devfreq); + +#endif /* _GOVERNOR_H */ diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c new file mode 100644 index 00000000000..c0596b29176 --- /dev/null +++ b/drivers/devfreq/governor_performance.c @@ -0,0 +1,29 @@ +/* + * linux/drivers/devfreq/governor_performance.c + * + * 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/devfreq.h> + +static int devfreq_performance_func(struct devfreq *df, + unsigned long *freq) +{ + /* + * target callback should be able to get floor value as + * said in devfreq.h + */ + *freq = UINT_MAX; + return 0; +} + +const struct devfreq_governor devfreq_performance = { + .name = "performance", + .get_target_freq = devfreq_performance_func, + .no_central_polling = true, +}; diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c new file mode 100644 index 00000000000..2483a85a266 --- /dev/null +++ b/drivers/devfreq/governor_powersave.c @@ -0,0 +1,29 @@ +/* + * linux/drivers/devfreq/governor_powersave.c + * + * 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/devfreq.h> + +static int devfreq_powersave_func(struct devfreq *df, + unsigned long *freq) +{ + /* + * target callback should be able to get ceiling value as + * said in devfreq.h + */ + *freq = 0; + return 0; +} + +const struct devfreq_governor devfreq_powersave = { + .name = "powersave", + .get_target_freq = devfreq_powersave_func, + .no_central_polling = true, +}; diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c new file mode 100644 index 00000000000..efad8dcf902 --- /dev/null +++ b/drivers/devfreq/governor_simpleondemand.c @@ -0,0 +1,88 @@ +/* + * linux/drivers/devfreq/governor_simpleondemand.c + * + * 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/errno.h> +#include <linux/devfreq.h> +#include <linux/math64.h> + +/* Default constants for DevFreq-Simple-Ondemand (DFSO) */ +#define DFSO_UPTHRESHOLD (90) +#define DFSO_DOWNDIFFERENCTIAL (5) +static int devfreq_simple_ondemand_func(struct devfreq *df, + unsigned long *freq) +{ + struct devfreq_dev_status stat; + int err = df->profile->get_dev_status(df->dev.parent, &stat); + unsigned long long a, b; + unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD; + unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL; + struct devfreq_simple_ondemand_data *data = df->data; + + if (err) + return err; + + if (data) { + if (data->upthreshold) + dfso_upthreshold = data->upthreshold; + if (data->downdifferential) + dfso_downdifferential = data->downdifferential; + } + if (dfso_upthreshold > 100 || + dfso_upthreshold < dfso_downdifferential) + return -EINVAL; + + /* Assume MAX if it is going to be divided by zero */ + if (stat.total_time == 0) { + *freq = UINT_MAX; + return 0; + } + + /* Prevent overflow */ + if (stat.busy_time >= (1 << 24) || stat.total_time >= (1 << 24)) { + stat.busy_time >>= 7; + stat.total_time >>= 7; + } + + /* Set MAX if it's busy enough */ + if (stat.busy_time * 100 > + stat.total_time * dfso_upthreshold) { + *freq = UINT_MAX; + return 0; + } + + /* Set MAX if we do not know the initial frequency */ + if (stat.current_frequency == 0) { + *freq = UINT_MAX; + return 0; + } + + /* Keep the current frequency */ + if (stat.busy_time * 100 > + stat.total_time * (dfso_upthreshold - dfso_downdifferential)) { + *freq = stat.current_frequency; + return 0; + } + + /* Set the desired frequency based on the load */ + a = stat.busy_time; + a *= stat.current_frequency; + b = div_u64(a, stat.total_time); + b *= 100; + b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2)); + *freq = (unsigned long) b; + + return 0; +} + +const struct devfreq_governor devfreq_simple_ondemand = { + .name = "simple_ondemand", + .get_target_freq = devfreq_simple_ondemand_func, +}; diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c new file mode 100644 index 00000000000..4f8b563da78 --- /dev/null +++ b/drivers/devfreq/governor_userspace.c @@ -0,0 +1,116 @@ +/* + * linux/drivers/devfreq/governor_simpleondemand.c + * + * 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/slab.h> +#include <linux/device.h> +#include <linux/devfreq.h> +#include <linux/pm.h> +#include <linux/mutex.h> +#include "governor.h" + +struct userspace_data { + unsigned long user_frequency; + bool valid; +}; + +static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq) +{ + struct userspace_data *data = df->data; + + if (!data->valid) + *freq = df->previous_freq; /* No user freq specified yet */ + else + *freq = data->user_frequency; + return 0; +} + +static ssize_t store_freq(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + struct devfreq *devfreq = to_devfreq(dev); + struct userspace_data *data; + unsigned long wanted; + int err = 0; + + + mutex_lock(&devfreq->lock); + data = devfreq->data; + + sscanf(buf, "%lu", &wanted); + data->user_frequency = wanted; + data->valid = true; + err = update_devfreq(devfreq); + if (err == 0) + err = count; + mutex_unlock(&devfreq->lock); + return err; +} + +static ssize_t show_freq(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct devfreq *devfreq = to_devfreq(dev); + struct userspace_data *data; + int err = 0; + + mutex_lock(&devfreq->lock); + data = devfreq->data; + + if (data->valid) + err = sprintf(buf, "%lu\n", data->user_frequency); + else + err = sprintf(buf, "undefined\n"); + mutex_unlock(&devfreq->lock); + return err; +} + +static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq); +static struct attribute *dev_entries[] = { + &dev_attr_set_freq.attr, + NULL, +}; +static struct attribute_group dev_attr_group = { + .name = "userspace", + .attrs = dev_entries, +}; + +static int userspace_init(struct devfreq *devfreq) +{ + int err = 0; + struct userspace_data *data = kzalloc(sizeof(struct userspace_data), + GFP_KERNEL); + + if (!data) { + err = -ENOMEM; + goto out; + } + data->valid = false; + devfreq->data = data; + + err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group); +out: + return err; +} + +static void userspace_exit(struct devfreq *devfreq) +{ + sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group); + kfree(devfreq->data); + devfreq->data = NULL; +} + +const struct devfreq_governor devfreq_userspace = { + .name = "userspace", + .get_target_freq = devfreq_userspace_func, + .init = userspace_init, + .exit = userspace_exit, + .no_central_polling = true, +}; |