diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-class-devfreq | 52 | ||||
| -rw-r--r-- | drivers/Kconfig | 2 | ||||
| -rw-r--r-- | drivers/Makefile | 2 | ||||
| -rw-r--r-- | drivers/base/power/opp.c | 30 | ||||
| -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 | ||||
| -rw-r--r-- | include/linux/devfreq.h | 238 | ||||
| -rw-r--r-- | include/linux/opp.h | 12 |
14 files changed, 1303 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-class-devfreq b/Documentation/ABI/testing/sysfs-class-devfreq new file mode 100644 index 00000000000..23d78b5aab1 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-class-devfreq @@ -0,0 +1,52 @@ +What: /sys/class/devfreq/.../ +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + Provide a place in sysfs for the devfreq objects. + This allows accessing various devfreq specific variables. + The name of devfreq object denoted as ... is same as the + name of device using devfreq. + +What: /sys/class/devfreq/.../governor +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../governor shows the name of the + governor used by the corresponding devfreq object. + +What: /sys/class/devfreq/.../cur_freq +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../cur_freq shows the current + frequency of the corresponding devfreq object. + +What: /sys/class/devfreq/.../central_polling +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../central_polling shows whether + the devfreq ojbect is using devfreq-provided central + polling mechanism or not. + +What: /sys/class/devfreq/.../polling_interval +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../polling_interval shows and sets + the requested polling interval of the corresponding devfreq + object. The values are represented in ms. If the value is + less than 1 jiffy, it is considered to be 0, which means + no polling. This value is meaningless if the governor is + not polling; thus. If the governor is not using + devfreq-provided central polling + (/sys/class/devfreq/.../central_polling is 0), this value + may be useless. + +What: /sys/class/devfreq/.../userspace/set_freq +Date: September 2011 +Contact: MyungJoo Ham <myungjoo.ham@samsung.com> +Description: + The /sys/class/devfreq/.../userspace/set_freq shows and + sets the requested frequency for the devfreq object if + userspace governor is in effect. diff --git a/drivers/Kconfig b/drivers/Kconfig index 95b9e7eefad..a1efd75070a 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -130,4 +130,6 @@ source "drivers/iommu/Kconfig" source "drivers/virt/Kconfig" +source "drivers/devfreq/Kconfig" + endmenu diff --git a/drivers/Makefile b/drivers/Makefile index 7fa433a7030..97c957b5081 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -127,3 +127,5 @@ obj-$(CONFIG_IOMMU_SUPPORT) += iommu/ # Virtualization drivers obj-$(CONFIG_VIRT_DRIVERS) += virt/ + +obj-$(CONFIG_PM_DEVFREQ) += devfreq/ diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index b23de185cb0..434a6c01167 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -73,6 +73,7 @@ struct opp { * RCU usage: nodes are not modified in the list of device_opp, * however addition is possible and is secured by dev_opp_list_lock * @dev: device pointer + * @head: notifier head to notify the OPP availability changes. * @opp_list: list of opps * * This is an internal data structure maintaining the link to opps attached to @@ -83,6 +84,7 @@ struct device_opp { struct list_head node; struct device *dev; + struct srcu_notifier_head head; struct list_head opp_list; }; @@ -404,6 +406,7 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) } dev_opp->dev = dev; + srcu_init_notifier_head(&dev_opp->head); INIT_LIST_HEAD(&dev_opp->opp_list); /* Secure the device list modification */ @@ -428,6 +431,11 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) list_add_rcu(&new_opp->node, head); mutex_unlock(&dev_opp_list_lock); + /* + * Notify the changes in the availability of the operable + * frequency/voltage list. + */ + srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ADD, new_opp); return 0; } @@ -504,6 +512,14 @@ static int opp_set_availability(struct device *dev, unsigned long freq, mutex_unlock(&dev_opp_list_lock); synchronize_rcu(); + /* Notify the change of the OPP availability */ + if (availability_req) + srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_ENABLE, + new_opp); + else + srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE, + new_opp); + /* clean up old opp */ new_opp = opp; goto out; @@ -643,3 +659,17 @@ void opp_free_cpufreq_table(struct device *dev, *table = NULL; } #endif /* CONFIG_CPU_FREQ */ + +/** + * opp_get_notifier() - find notifier_head of the device with opp + * @dev: device pointer used to lookup device OPPs. + */ +struct srcu_notifier_head *opp_get_notifier(struct device *dev) +{ + struct device_opp *dev_opp = find_device_opp(dev); + + if (IS_ERR(dev_opp)) + return ERR_PTR(PTR_ERR(dev_opp)); /* matching type */ + + return &dev_opp->head; +} 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, +}; diff --git a/include/linux/devfreq.h b/include/linux/devfreq.h new file mode 100644 index 00000000000..afb94583960 --- /dev/null +++ b/include/linux/devfreq.h @@ -0,0 +1,238 @@ +/* + * 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/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_date; +}; + +/** + * 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. + * @get_dev_status The device should provide the current performance + * status to devfreq, which is used by governors. + * @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. + */ +struct devfreq_dev_profile { + unsigned long initial_freq; + unsigned int polling_ms; + + int (*target)(struct device *dev, unsigned long *freq); + int (*get_dev_status)(struct device *dev, + struct devfreq_dev_status *stat); + void (*exit)(struct device *dev); +}; + +/** + * struct devfreq_governor - Devfreq policy governor + * @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. + * @init Called when the devfreq is being attached to a device + * @exit Called when the devfreq is being removed from a + * device. Governor should stop any internal routines + * before return because related data may be + * freed after exit(). + * @no_central_polling Do not use devfreq's central polling mechanism. + * When this is set, devfreq will not call + * get_target_freq with devfreq_monitor(). However, + * devfreq will call get_target_freq with + * devfreq_update() notified by OPP framework. + * + * Note that the callbacks are called with devfreq->lock locked by devfreq. + */ +struct devfreq_governor { + const char name[DEVFREQ_NAME_LEN]; + int (*get_target_freq)(struct devfreq *this, unsigned long *freq); + int (*init)(struct devfreq *this); + void (*exit)(struct devfreq *this); + const bool no_central_polling; +}; + +/** + * 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. + * @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. + * @polling_jiffies interval in jiffies. + * @previous_freq previously configured frequency value. + * @next_polling the number of remaining jiffies to poll with + * "devfreq_monitor" executions to reevaluate + * frequency/voltage of the device. Set by + * profile's polling_ms interval. + * @data Private data of the governor. The devfreq framework does not + * touch this. + * @being_removed a flag to mark that this object is being removed in + * order to prevent trying to remove the object multiple times. + * + * 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; + struct notifier_block nb; + + unsigned long polling_jiffies; + unsigned long previous_freq; + unsigned int next_polling; + + void *data; /* private data for governors */ + + bool being_removed; +}; + +#if defined(CONFIG_PM_DEVFREQ) +extern struct devfreq *devfreq_add_device(struct device *dev, + struct devfreq_dev_profile *profile, + const struct devfreq_governor *governor, + void *data); +extern int devfreq_remove_device(struct devfreq *devfreq); + +/* Helper functions for devfreq user device driver with OPP. */ +extern struct opp *devfreq_recommended_opp(struct device *dev, + unsigned long *freq); +extern int devfreq_register_opp_notifier(struct device *dev, + struct devfreq *devfreq); +extern int devfreq_unregister_opp_notifier(struct device *dev, + struct devfreq *devfreq); + +#ifdef CONFIG_DEVFREQ_GOV_POWERSAVE +extern const struct devfreq_governor devfreq_powersave; +#endif +#ifdef CONFIG_DEVFREQ_GOV_PERFORMANCE +extern const struct devfreq_governor devfreq_performance; +#endif +#ifdef CONFIG_DEVFREQ_GOV_USERSPACE +extern const struct devfreq_governor devfreq_userspace; +#endif +#ifdef CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND +extern const struct devfreq_governor devfreq_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 struct devfreq *devfreq_add_device(struct device *dev, + struct devfreq_dev_profile *profile, + struct devfreq_governor *governor, + void *data); +{ + return NULL; +} + +static int devfreq_remove_device(struct devfreq *devfreq); +{ + return 0; +} + +static struct opp *devfreq_recommended_opp(struct device *dev, + unsigned long *freq) +{ + return -EINVAL; +} + +static int devfreq_register_opp_notifier(struct device *dev, + struct devfreq *devfreq) +{ + return -EINVAL; +} + +static int devfreq_unregister_opp_notifier(struct device *dev, + struct devfreq *devfreq) +{ + return -EINVAL; +} + +#define devfreq_powersave NULL +#define devfreq_performance NULL +#define devfreq_userspace NULL +#define devfreq_simple_ondemand NULL + +#endif /* CONFIG_PM_DEVFREQ */ + +#endif /* __LINUX_DEVFREQ_H__ */ diff --git a/include/linux/opp.h b/include/linux/opp.h index 7020e9736fc..87a9208f8ae 100644 --- a/include/linux/opp.h +++ b/include/linux/opp.h @@ -16,9 +16,14 @@ #include <linux/err.h> #include <linux/cpufreq.h> +#include <linux/notifier.h> struct opp; +enum opp_event { + OPP_EVENT_ADD, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE, +}; + #if defined(CONFIG_PM_OPP) unsigned long opp_get_voltage(struct opp *opp); @@ -40,6 +45,8 @@ int opp_enable(struct device *dev, unsigned long freq); int opp_disable(struct device *dev, unsigned long freq); +struct srcu_notifier_head *opp_get_notifier(struct device *dev); + #else static inline unsigned long opp_get_voltage(struct opp *opp) { @@ -89,6 +96,11 @@ static inline int opp_disable(struct device *dev, unsigned long freq) { return 0; } + +struct srcu_notifier_head *opp_get_notifier(struct device *dev) +{ + return ERR_PTR(-EINVAL); +} #endif /* CONFIG_PM */ #if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP) |