--- /dev/null
+/*
+ * 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;
+}
+
+/**
+ * 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);
+ }
+ 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");
git.openpandora.org / pandora-kernel.git / blobdiff