@@ -4,5 +4,6 @@ obj-$(CONFIG_PM_RUNTIME) += runtime.o
obj-$(CONFIG_PM_TRACE_RTC) += trace.o
obj-$(CONFIG_PM_OPP) += opp.o
obj-$(CONFIG_HAVE_CLK) += clock_ops.o
+obj-$(CONFIG_PM_DEVFREQ) += devfreq.o
ccflags-$(CONFIG_DEBUG_DRIVER) := -DDEBUG
\ No newline at end of file
new file mode 100644
@@ -0,0 +1,397 @@
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ * for Non-CPU Devices Based on OPP.
+ *
+ * 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/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>
+
+/*
+ * devfreq polling interval in ms.
+ * It is recommended to be "jiffy_in_ms" * n, where n is an integer >= 1.
+ */
+#define DEVFREQ_INTERVAL 20
+
+/*
+ * devfreq_work periodically (given by DEVFREQ_INTERVAL) monitors every
+ * registered device.
+ */
+static bool polling;
+static struct workqueue_struct *devfreq_wq;
+static struct delayed_work devfreq_work;
+
+/* 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("%s: Invalid parameters\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
+ if (tmp_devfreq->dev == dev)
+ return tmp_devfreq;
+ }
+
+ return ERR_PTR(-ENODEV);
+}
+
+/**
+ * devfreq_do() - Check the usage profile of a given device and configure
+ * frequency and voltage accordingly
+ * @devfreq: devfreq info of the given device
+ */
+static int devfreq_do(struct devfreq *devfreq)
+{
+ struct opp *opp;
+ unsigned long freq;
+ int err;
+
+ err = devfreq->governor->get_target_freq(devfreq, &freq);
+ if (err)
+ return err;
+
+ opp = opp_find_freq_ceil(devfreq->dev, &freq);
+ if (opp == ERR_PTR(-ENODEV))
+ opp = opp_find_freq_floor(devfreq->dev, &freq);
+
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ if (devfreq->previous_freq == freq)
+ return 0;
+
+ err = devfreq->profile->target(devfreq->dev, opp);
+ if (err)
+ return err;
+
+ devfreq->previous_freq = freq;
+ return 0;
+}
+
+/**
+ * devfreq_monitor() - Periodically run devfreq_do() and support
+ * device devfreq tickle.
+ * @work: the work struct used to run devfreq_monitor periodically.
+ *
+ * Tickle is to force a device to operate at its maximum operable frequency
+ * for a while temporarily. Look at devfreq_tickle_device() for more
+ * information about tickle.
+ */
+static void devfreq_monitor(struct work_struct *work)
+{
+ struct devfreq *devfreq, *tmp;
+ int error;
+
+ mutex_lock(&devfreq_list_lock);
+
+ polling = false;
+
+ list_for_each_entry_safe(devfreq, tmp, &devfreq_list, node) {
+ /*
+ * If the device is tickled and the tickle duration is left,
+ * do not change the frequency for a while
+ */
+ if (devfreq->tickle) {
+ polling = true;
+ devfreq->tickle--;
+
+ /*
+ * If tickling is ending and the device is not going
+ * to poll, force the device to poll next time so that
+ * it can return to the original frequency.
+ * However, as a non-polling device has 0 polling_ms,
+ * it will not poll again later.
+ */
+ if (devfreq->tickle == 0 && devfreq->next_polling == 0)
+ devfreq->next_polling = 1;
+
+ continue;
+ }
+
+ if (devfreq->next_polling == 0)
+ continue;
+
+ polling = true;
+
+ if (devfreq->next_polling-- == 1) {
+ error = devfreq_do(devfreq);
+
+ /* Remove a devfreq with an error. */
+ if (error && error != -EAGAIN) {
+ dev_err(devfreq->dev, "devfreq_do error(%d). "
+ "devfreq is removed from the device\n",
+ error);
+
+ list_del(&devfreq->node);
+ kfree(devfreq);
+
+ continue;
+ }
+ devfreq->next_polling = DIV_ROUND_UP(
+ devfreq->profile->polling_ms,
+ DEVFREQ_INTERVAL);
+ }
+ }
+
+ if (polling)
+ queue_delayed_work(devfreq_wq, &devfreq_work,
+ msecs_to_jiffies(DEVFREQ_INTERVAL));
+
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * 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.
+ */
+int devfreq_add_device(struct device *dev, struct devfreq_dev_profile *profile,
+ struct devfreq_governor *governor)
+{
+ struct devfreq *new_devfreq, *devfreq;
+ int err = 0;
+
+ if (!dev || !profile || !governor) {
+ dev_err(dev, "%s: Invalid parameters.\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&devfreq_list_lock);
+
+ devfreq = find_device_devfreq(dev);
+ 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;
+ }
+
+ new_devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
+ if (!new_devfreq) {
+ dev_err(dev, "%s: Unable to create devfreq for the device\n",
+ __func__);
+ err = -ENOMEM;
+ goto out;
+ }
+
+ new_devfreq->dev = dev;
+ new_devfreq->profile = profile;
+ new_devfreq->governor = governor;
+ new_devfreq->next_polling = DIV_ROUND_UP(profile->polling_ms,
+ DEVFREQ_INTERVAL);
+ new_devfreq->previous_freq = profile->initial_freq;
+
+ list_add(&new_devfreq->node, &devfreq_list);
+
+ if (devfreq_wq && new_devfreq->next_polling && !polling) {
+ polling = true;
+ queue_delayed_work(devfreq_wq, &devfreq_work,
+ msecs_to_jiffies(DEVFREQ_INTERVAL));
+ }
+out:
+ mutex_unlock(&devfreq_list_lock);
+
+ return err;
+}
+
+/**
+ * devfreq_remove_device() - Remove devfreq feature from a device.
+ * @device: the device to remove devfreq feature.
+ */
+int devfreq_remove_device(struct device *dev)
+{
+ struct devfreq *devfreq;
+
+ if (!dev)
+ return -EINVAL;
+
+ mutex_lock(&devfreq_list_lock);
+ devfreq = find_device_devfreq(dev);
+ if (IS_ERR(devfreq)) {
+ dev_err(dev, "%s: Unable to find devfreq entry for the device.\n",
+ __func__);
+ mutex_unlock(&devfreq_list_lock);
+ return -EINVAL;
+ }
+
+ list_del(&devfreq->node);
+
+ kfree(devfreq);
+
+ mutex_unlock(&devfreq_list_lock);
+
+ return 0;
+}
+
+/**
+ * devfreq_update() - Notify that the device OPP has been changed.
+ * @dev: the device whose OPP has been changed.
+ */
+int devfreq_update(struct device *dev)
+{
+ struct devfreq *devfreq;
+ int err = 0;
+
+ mutex_lock(&devfreq_list_lock);
+
+ devfreq = find_device_devfreq(dev);
+ if (IS_ERR(devfreq)) {
+ err = PTR_ERR(devfreq);
+ goto out;
+ }
+
+ /*
+ * If the maximum frequency available is changed either by
+ * enabling higher frequency or disabling the current
+ * maximum frequency, we need to adjust the frequency
+ * (tickle) again if the device has been being tickled.
+ */
+ if (devfreq->tickle) {
+ unsigned long freq = devfreq->profile->max_freq;
+ struct opp *opp = opp_find_freq_floor(devfreq->dev, &freq);
+
+ if (IS_ERR(opp)) {
+ err = PTR_ERR(opp);
+ goto out;
+ }
+
+ /* Max freq available is not changed */
+ if (devfreq->previous_freq == freq)
+ goto out;
+
+ /* Tickle again. Max freq available is changed */
+ err = devfreq->profile->target(devfreq->dev, opp);
+ if (!err)
+ devfreq->previous_freq = freq;
+ } else {
+ /* Reevaluate the proper frequency */
+ err = devfreq_do(devfreq);
+ }
+
+out:
+ mutex_unlock(&devfreq_list_lock);
+ return err;
+}
+
+/**
+ * _devfreq_tickle_device() - Adjust operating frequency at maximum and
+ * keep the frequency for the designiated delay.
+ * @df: devfreq entry of the device being tickled.
+ * @delay: duration of tickle effect in the number of polling.
+ */
+static int _devfreq_tickle_device(struct devfreq *df, unsigned long delay)
+{
+ int err = 0;
+ unsigned long freq;
+ struct opp *opp;
+
+ freq = df->profile->max_freq;
+ opp = opp_find_freq_floor(df->dev, &freq);
+ if (IS_ERR(opp))
+ return PTR_ERR(opp);
+
+ if (df->previous_freq != freq) {
+ err = df->profile->target(df->dev, opp);
+ if (!err)
+ df->previous_freq = freq;
+ }
+ if (err) {
+ dev_err(df->dev, "%s: Cannot set frequency.\n", __func__);
+ } else {
+ /* Do not shorten tickle duration with a new tickle call */
+ if (df->tickle < delay)
+ df->tickle = delay;
+
+ df->num_tickle++;
+ }
+
+ if (devfreq_wq && !polling) {
+ polling = true;
+ queue_delayed_work(devfreq_wq, &devfreq_work,
+ msecs_to_jiffies(DEVFREQ_INTERVAL));
+ }
+
+ return err;
+}
+
+/**
+ * devfreq_tickle_device() - Guarantee maximum operation speed for a while
+ * instaneously.
+ * @dev: the device to be tickled.
+ * @duration_ms: the duration of tickle effect.
+ *
+ * Tickle sets the device at the maximum frequency instaneously and
+ * the maximum frequency is guaranteed to be used for the given duration.
+ * For faster user reponse time, an input event may tickle a related device
+ * so that the input event does not need to wait for the devfreq to react with
+ * normal interval.
+ *
+ * _devfreq_tickle_device() is used as a helper function for tickling.
+ */
+int devfreq_tickle_device(struct device *dev, unsigned long duration_ms)
+{
+ struct devfreq *devfreq;
+ int err = 0;
+ unsigned long delay; /* in # of DEVFREQ_INTERVAL */
+
+ mutex_lock(&devfreq_list_lock);
+ devfreq = find_device_devfreq(dev);
+ delay = DIV_ROUND_UP(duration_ms, DEVFREQ_INTERVAL);
+
+ if (IS_ERR(devfreq))
+ err = PTR_ERR(devfreq);
+ else
+ err = _devfreq_tickle_device(devfreq, delay);
+
+ mutex_unlock(&devfreq_list_lock);
+
+ return err;
+}
+
+/**
+ * devfreq_init() - Initialize data structure for devfreq framework and
+ * start polling registered devfreq devices.
+ */
+static int __init devfreq_init(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_init);
@@ -21,6 +21,7 @@
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/opp.h>
+#include <linux/devfreq.h>
/*
* Internal data structure organization with the OPP layer library is as
@@ -428,6 +429,11 @@ 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 generic dvfs for the change and ignore error
+ * because the device may not have a devfreq entry
+ */
+ devfreq_update(dev);
return 0;
}
@@ -512,6 +518,9 @@ unlock:
mutex_unlock(&dev_opp_list_lock);
out:
kfree(new_opp);
+
+ /* Notify generic dvfs for the change and ignore error */
+ devfreq_update(dev);
return r;
}
new file mode 100644
@@ -0,0 +1,111 @@
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ * for Non-CPU Devices Based on OPP.
+ *
+ * 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__
+
+#define DEVFREQ_NAME_LEN 16
+
+struct devfreq;
+struct devfreq_dev_status {
+ /* both since the last measure */
+ unsigned long total_time;
+ unsigned long busy_time;
+ unsigned long current_frequency;
+};
+
+struct devfreq_dev_profile {
+ unsigned long max_freq; /* may be larger than the actual value */
+ unsigned long initial_freq;
+ int polling_ms; /* 0 for at opp change only */
+
+ int (*target)(struct device *dev, struct opp *opp);
+ int (*get_dev_status)(struct device *dev,
+ struct devfreq_dev_status *stat);
+};
+
+/**
+ * struct devfreq_governor - DEVFREQ Policy Governor
+ * @data Governor's internal data. The framework does not care of it.
+ * @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).
+ */
+struct devfreq_governor {
+ char name[DEVFREQ_NAME_LEN];
+ void *data; /* private data for get_target_freq */
+ int (*get_target_freq)(struct devfreq *this, unsigned long *freq);
+};
+
+/**
+ * struct devfreq - Device DEVFREQ structure
+ * @node list node - contains the devices with DEVFREQ that have been
+ * registered.
+ * @dev device pointer
+ * @profile device-specific devfreq profile
+ * @governor method how to choose frequency based on the usage.
+ * @previous_freq previously configured frequency value.
+ * @next_polling the number of remaining "devfreq_monitor" executions to
+ * reevaluate frequency/voltage of the device. Set by
+ * profile's polling_ms interval.
+ * @tickle positive if DEVFREQ-tickling is activated for the device.
+ * at each executino of devfreq_monitor, tickle is decremented.
+ * User may tickle a device-devfreq in order to set maximum
+ * frequency instaneously with some guaranteed duration.
+ *
+ * This structure stores the DEVFREQ information for a give device.
+ */
+struct devfreq {
+ struct list_head node;
+
+ struct device *dev;
+ struct devfreq_dev_profile *profile;
+ struct devfreq_governor *governor;
+
+ unsigned long previous_freq;
+ unsigned int next_polling;
+ unsigned int tickle;
+};
+
+#if defined(CONFIG_PM_DEVFREQ)
+extern int devfreq_add_device(struct device *dev,
+ struct devfreq_dev_profile *profile,
+ struct devfreq_governor *governor);
+extern int devfreq_remove_device(struct device *dev);
+extern int devfreq_update(struct device *dev);
+extern int devfreq_tickle_device(struct device *dev, unsigned long duration_ms);
+#else /* !CONFIG_PM_DEVFREQ */
+static int devfreq_add_device(struct device *dev,
+ struct devfreq_dev_profile *profile,
+ struct devfreq_governor *governor)
+{
+ return 0;
+}
+
+static int devfreq_remove_device(struct device *dev)
+{
+ return 0;
+}
+
+static int devfreq_update(struct device *dev)
+{
+ return 0;
+}
+
+static int devfreq_tickle_device(struct device *dev, unsigned long duration_ms)
+{
+ return 0;
+}
+#endif /* CONFIG_PM_DEVFREQ */
+
+#endif /* __LINUX_DEVFREQ_H__ */
@@ -227,3 +227,37 @@ config PM_OPP
config PM_RUNTIME_CLK
def_bool y
depends on PM_RUNTIME && HAVE_CLK
+
+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.
+
+config PM_DEVFREQ
+ bool "Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework"
+ 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.