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-rw-r--r--drivers/devfreq/devfreq.c2275
1 files changed, 2275 insertions, 0 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
new file mode 100644
index 000000000..2951a87cc
--- /dev/null
+++ b/drivers/devfreq/devfreq.c
@@ -0,0 +1,2275 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * devfreq: Generic Dynamic Voltage and Frequency Scaling (DVFS) Framework
+ * for Non-CPU Devices.
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@samsung.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/kmod.h>
+#include <linux/sched.h>
+#include <linux/debugfs.h>
+#include <linux/devfreq_cooling.h>
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/stat.h>
+#include <linux/pm_opp.h>
+#include <linux/devfreq.h>
+#include <linux/workqueue.h>
+#include <linux/platform_device.h>
+#include <linux/list.h>
+#include <linux/printk.h>
+#include <linux/hrtimer.h>
+#include <linux/of.h>
+#include <linux/pm_qos.h>
+#include <linux/units.h>
+#include "governor.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/devfreq.h>
+
+#define IS_SUPPORTED_FLAG(f, name) ((f & DEVFREQ_GOV_FLAG_##name) ? true : false)
+#define IS_SUPPORTED_ATTR(f, name) ((f & DEVFREQ_GOV_ATTR_##name) ? true : false)
+
+static struct class *devfreq_class;
+static struct dentry *devfreq_debugfs;
+
+/*
+ * devfreq core provides delayed work based load monitoring helper
+ * functions. Governors can use these or can implement their own
+ * monitoring mechanism.
+ */
+static struct workqueue_struct *devfreq_wq;
+
+/* The list of all device-devfreq governors */
+static LIST_HEAD(devfreq_governor_list);
+/* The list of all device-devfreq */
+static LIST_HEAD(devfreq_list);
+static DEFINE_MUTEX(devfreq_list_lock);
+
+static const char timer_name[][DEVFREQ_NAME_LEN] = {
+ [DEVFREQ_TIMER_DEFERRABLE] = { "deferrable" },
+ [DEVFREQ_TIMER_DELAYED] = { "delayed" },
+};
+
+/**
+ * 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;
+
+ lockdep_assert_held(&devfreq_list_lock);
+
+ if (IS_ERR_OR_NULL(dev)) {
+ pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ list_for_each_entry(tmp_devfreq, &devfreq_list, node) {
+ if (tmp_devfreq->dev.parent == dev)
+ return tmp_devfreq;
+ }
+
+ return ERR_PTR(-ENODEV);
+}
+
+static unsigned long find_available_min_freq(struct devfreq *devfreq)
+{
+ struct dev_pm_opp *opp;
+ unsigned long min_freq = 0;
+
+ opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &min_freq);
+ if (IS_ERR(opp))
+ min_freq = 0;
+ else
+ dev_pm_opp_put(opp);
+
+ return min_freq;
+}
+
+static unsigned long find_available_max_freq(struct devfreq *devfreq)
+{
+ struct dev_pm_opp *opp;
+ unsigned long max_freq = ULONG_MAX;
+
+ opp = dev_pm_opp_find_freq_floor(devfreq->dev.parent, &max_freq);
+ if (IS_ERR(opp))
+ max_freq = 0;
+ else
+ dev_pm_opp_put(opp);
+
+ return max_freq;
+}
+
+/**
+ * devfreq_get_freq_range() - Get the current freq range
+ * @devfreq: the devfreq instance
+ * @min_freq: the min frequency
+ * @max_freq: the max frequency
+ *
+ * This takes into consideration all constraints.
+ */
+void devfreq_get_freq_range(struct devfreq *devfreq,
+ unsigned long *min_freq,
+ unsigned long *max_freq)
+{
+ unsigned long *freq_table = devfreq->freq_table;
+ s32 qos_min_freq, qos_max_freq;
+
+ lockdep_assert_held(&devfreq->lock);
+
+ /*
+ * Initialize minimum/maximum frequency from freq table.
+ * The devfreq drivers can initialize this in either ascending or
+ * descending order and devfreq core supports both.
+ */
+ if (freq_table[0] < freq_table[devfreq->max_state - 1]) {
+ *min_freq = freq_table[0];
+ *max_freq = freq_table[devfreq->max_state - 1];
+ } else {
+ *min_freq = freq_table[devfreq->max_state - 1];
+ *max_freq = freq_table[0];
+ }
+
+ /* Apply constraints from PM QoS */
+ qos_min_freq = dev_pm_qos_read_value(devfreq->dev.parent,
+ DEV_PM_QOS_MIN_FREQUENCY);
+ qos_max_freq = dev_pm_qos_read_value(devfreq->dev.parent,
+ DEV_PM_QOS_MAX_FREQUENCY);
+ *min_freq = max(*min_freq, (unsigned long)HZ_PER_KHZ * qos_min_freq);
+ if (qos_max_freq != PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE)
+ *max_freq = min(*max_freq,
+ (unsigned long)HZ_PER_KHZ * qos_max_freq);
+
+ /* Apply constraints from OPP interface */
+ *min_freq = max(*min_freq, devfreq->scaling_min_freq);
+ *max_freq = min(*max_freq, devfreq->scaling_max_freq);
+
+ if (*min_freq > *max_freq)
+ *min_freq = *max_freq;
+}
+EXPORT_SYMBOL(devfreq_get_freq_range);
+
+/**
+ * devfreq_get_freq_level() - Lookup freq_table for the frequency
+ * @devfreq: the devfreq instance
+ * @freq: the target frequency
+ */
+static int devfreq_get_freq_level(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev;
+
+ for (lev = 0; lev < devfreq->max_state; lev++)
+ if (freq == devfreq->freq_table[lev])
+ return lev;
+
+ return -EINVAL;
+}
+
+static int set_freq_table(struct devfreq *devfreq)
+{
+ struct dev_pm_opp *opp;
+ unsigned long freq;
+ int i, count;
+
+ /* Initialize the freq_table from OPP table */
+ count = dev_pm_opp_get_opp_count(devfreq->dev.parent);
+ if (count <= 0)
+ return -EINVAL;
+
+ devfreq->max_state = count;
+ devfreq->freq_table = devm_kcalloc(devfreq->dev.parent,
+ devfreq->max_state,
+ sizeof(*devfreq->freq_table),
+ GFP_KERNEL);
+ if (!devfreq->freq_table)
+ return -ENOMEM;
+
+ for (i = 0, freq = 0; i < devfreq->max_state; i++, freq++) {
+ opp = dev_pm_opp_find_freq_ceil(devfreq->dev.parent, &freq);
+ if (IS_ERR(opp)) {
+ devm_kfree(devfreq->dev.parent, devfreq->freq_table);
+ return PTR_ERR(opp);
+ }
+ dev_pm_opp_put(opp);
+ devfreq->freq_table[i] = freq;
+ }
+
+ return 0;
+}
+
+/**
+ * devfreq_update_status() - Update statistics of devfreq behavior
+ * @devfreq: the devfreq instance
+ * @freq: the update target frequency
+ */
+int devfreq_update_status(struct devfreq *devfreq, unsigned long freq)
+{
+ int lev, prev_lev, ret = 0;
+ u64 cur_time;
+
+ lockdep_assert_held(&devfreq->lock);
+ cur_time = get_jiffies_64();
+
+ /* Immediately exit if previous_freq is not initialized yet. */
+ if (!devfreq->previous_freq)
+ goto out;
+
+ prev_lev = devfreq_get_freq_level(devfreq, devfreq->previous_freq);
+ if (prev_lev < 0) {
+ ret = prev_lev;
+ goto out;
+ }
+
+ devfreq->stats.time_in_state[prev_lev] +=
+ cur_time - devfreq->stats.last_update;
+
+ lev = devfreq_get_freq_level(devfreq, freq);
+ if (lev < 0) {
+ ret = lev;
+ goto out;
+ }
+
+ if (lev != prev_lev) {
+ devfreq->stats.trans_table[
+ (prev_lev * devfreq->max_state) + lev]++;
+ devfreq->stats.total_trans++;
+ }
+
+out:
+ devfreq->stats.last_update = cur_time;
+ return ret;
+}
+EXPORT_SYMBOL(devfreq_update_status);
+
+/**
+ * find_devfreq_governor() - find devfreq governor from name
+ * @name: name of the governor
+ *
+ * Search the list of devfreq governors and return the matched
+ * governor's pointer. devfreq_list_lock should be held by the caller.
+ */
+static struct devfreq_governor *find_devfreq_governor(const char *name)
+{
+ struct devfreq_governor *tmp_governor;
+
+ lockdep_assert_held(&devfreq_list_lock);
+
+ if (IS_ERR_OR_NULL(name)) {
+ pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ list_for_each_entry(tmp_governor, &devfreq_governor_list, node) {
+ if (!strncmp(tmp_governor->name, name, DEVFREQ_NAME_LEN))
+ return tmp_governor;
+ }
+
+ return ERR_PTR(-ENODEV);
+}
+
+/**
+ * try_then_request_governor() - Try to find the governor and request the
+ * module if is not found.
+ * @name: name of the governor
+ *
+ * Search the list of devfreq governors and request the module and try again
+ * if is not found. This can happen when both drivers (the governor driver
+ * and the driver that call devfreq_add_device) are built as modules.
+ * devfreq_list_lock should be held by the caller. Returns the matched
+ * governor's pointer or an error pointer.
+ */
+static struct devfreq_governor *try_then_request_governor(const char *name)
+{
+ struct devfreq_governor *governor;
+ int err = 0;
+
+ lockdep_assert_held(&devfreq_list_lock);
+
+ if (IS_ERR_OR_NULL(name)) {
+ pr_err("DEVFREQ: %s: Invalid parameters\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ governor = find_devfreq_governor(name);
+ if (IS_ERR(governor)) {
+ mutex_unlock(&devfreq_list_lock);
+
+ if (!strncmp(name, DEVFREQ_GOV_SIMPLE_ONDEMAND,
+ DEVFREQ_NAME_LEN))
+ err = request_module("governor_%s", "simpleondemand");
+ else
+ err = request_module("governor_%s", name);
+ /* Restore previous state before return */
+ mutex_lock(&devfreq_list_lock);
+ if (err)
+ return (err < 0) ? ERR_PTR(err) : ERR_PTR(-EINVAL);
+
+ governor = find_devfreq_governor(name);
+ }
+
+ return governor;
+}
+
+static int devfreq_notify_transition(struct devfreq *devfreq,
+ struct devfreq_freqs *freqs, unsigned int state)
+{
+ if (!devfreq)
+ return -EINVAL;
+
+ switch (state) {
+ case DEVFREQ_PRECHANGE:
+ srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+ DEVFREQ_PRECHANGE, freqs);
+ break;
+
+ case DEVFREQ_POSTCHANGE:
+ srcu_notifier_call_chain(&devfreq->transition_notifier_list,
+ DEVFREQ_POSTCHANGE, freqs);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int devfreq_set_target(struct devfreq *devfreq, unsigned long new_freq,
+ u32 flags)
+{
+ struct devfreq_freqs freqs;
+ unsigned long cur_freq;
+ int err = 0;
+
+ if (devfreq->profile->get_cur_freq)
+ devfreq->profile->get_cur_freq(devfreq->dev.parent, &cur_freq);
+ else
+ cur_freq = devfreq->previous_freq;
+
+ freqs.old = cur_freq;
+ freqs.new = new_freq;
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_PRECHANGE);
+
+ err = devfreq->profile->target(devfreq->dev.parent, &new_freq, flags);
+ if (err) {
+ freqs.new = cur_freq;
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+ return err;
+ }
+
+ /*
+ * Print devfreq_frequency trace information between DEVFREQ_PRECHANGE
+ * and DEVFREQ_POSTCHANGE because for showing the correct frequency
+ * change order of between devfreq device and passive devfreq device.
+ */
+ if (trace_devfreq_frequency_enabled() && new_freq != cur_freq)
+ trace_devfreq_frequency(devfreq, new_freq, cur_freq);
+
+ freqs.new = new_freq;
+ devfreq_notify_transition(devfreq, &freqs, DEVFREQ_POSTCHANGE);
+
+ if (devfreq_update_status(devfreq, new_freq))
+ dev_warn(&devfreq->dev,
+ "Couldn't update frequency transition information.\n");
+
+ devfreq->previous_freq = new_freq;
+
+ if (devfreq->suspend_freq)
+ devfreq->resume_freq = new_freq;
+
+ return err;
+}
+
+/**
+ * devfreq_update_target() - Reevaluate the device and configure frequency
+ * on the final stage.
+ * @devfreq: the devfreq instance.
+ * @freq: the new frequency of parent device. This argument
+ * is only used for devfreq device using passive governor.
+ *
+ * Note: Lock devfreq->lock before calling devfreq_update_target. This function
+ * should be only used by both update_devfreq() and devfreq governors.
+ */
+int devfreq_update_target(struct devfreq *devfreq, unsigned long freq)
+{
+ unsigned long min_freq, max_freq;
+ int err = 0;
+ u32 flags = 0;
+
+ lockdep_assert_held(&devfreq->lock);
+
+ if (!devfreq->governor)
+ return -EINVAL;
+
+ /* Reevaluate the proper frequency */
+ err = devfreq->governor->get_target_freq(devfreq, &freq);
+ if (err)
+ return err;
+ devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+
+ if (freq < min_freq) {
+ freq = min_freq;
+ flags &= ~DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use GLB */
+ }
+ if (freq > max_freq) {
+ freq = max_freq;
+ flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
+ }
+
+ return devfreq_set_target(devfreq, freq, flags);
+}
+EXPORT_SYMBOL(devfreq_update_target);
+
+/* Load monitoring helper functions for governors use */
+
+/**
+ * update_devfreq() - Reevaluate the device and configure frequency.
+ * @devfreq: the devfreq instance.
+ *
+ * Note: Lock devfreq->lock before calling update_devfreq
+ * This function is exported for governors.
+ */
+int update_devfreq(struct devfreq *devfreq)
+{
+ return devfreq_update_target(devfreq, 0L);
+}
+EXPORT_SYMBOL(update_devfreq);
+
+/**
+ * devfreq_monitor() - Periodically poll devfreq objects.
+ * @work: the work struct used to run devfreq_monitor periodically.
+ *
+ */
+static void devfreq_monitor(struct work_struct *work)
+{
+ int err;
+ struct devfreq *devfreq = container_of(work,
+ struct devfreq, work.work);
+
+ mutex_lock(&devfreq->lock);
+ err = update_devfreq(devfreq);
+ if (err)
+ dev_err(&devfreq->dev, "dvfs failed with (%d) error\n", err);
+
+ queue_delayed_work(devfreq_wq, &devfreq->work,
+ msecs_to_jiffies(devfreq->profile->polling_ms));
+ mutex_unlock(&devfreq->lock);
+
+ trace_devfreq_monitor(devfreq);
+}
+
+/**
+ * devfreq_monitor_start() - Start load monitoring of devfreq instance
+ * @devfreq: the devfreq instance.
+ *
+ * Helper function for starting devfreq device load monitoring. By
+ * default delayed work based monitoring is supported. Function
+ * to be called from governor in response to DEVFREQ_GOV_START
+ * event when device is added to devfreq framework.
+ */
+void devfreq_monitor_start(struct devfreq *devfreq)
+{
+ if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+ return;
+
+ switch (devfreq->profile->timer) {
+ case DEVFREQ_TIMER_DEFERRABLE:
+ INIT_DEFERRABLE_WORK(&devfreq->work, devfreq_monitor);
+ break;
+ case DEVFREQ_TIMER_DELAYED:
+ INIT_DELAYED_WORK(&devfreq->work, devfreq_monitor);
+ break;
+ default:
+ return;
+ }
+
+ if (devfreq->profile->polling_ms)
+ queue_delayed_work(devfreq_wq, &devfreq->work,
+ msecs_to_jiffies(devfreq->profile->polling_ms));
+}
+EXPORT_SYMBOL(devfreq_monitor_start);
+
+/**
+ * devfreq_monitor_stop() - Stop load monitoring of a devfreq instance
+ * @devfreq: the devfreq instance.
+ *
+ * Helper function to stop devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_STOP
+ * event when device is removed from devfreq framework.
+ */
+void devfreq_monitor_stop(struct devfreq *devfreq)
+{
+ if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+ return;
+
+ cancel_delayed_work_sync(&devfreq->work);
+}
+EXPORT_SYMBOL(devfreq_monitor_stop);
+
+/**
+ * devfreq_monitor_suspend() - Suspend load monitoring of a devfreq instance
+ * @devfreq: the devfreq instance.
+ *
+ * Helper function to suspend devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_SUSPEND
+ * event or when polling interval is set to zero.
+ *
+ * Note: Though this function is same as devfreq_monitor_stop(),
+ * intentionally kept separate to provide hooks for collecting
+ * transition statistics.
+ */
+void devfreq_monitor_suspend(struct devfreq *devfreq)
+{
+ mutex_lock(&devfreq->lock);
+ if (devfreq->stop_polling) {
+ mutex_unlock(&devfreq->lock);
+ return;
+ }
+
+ devfreq_update_status(devfreq, devfreq->previous_freq);
+ devfreq->stop_polling = true;
+ mutex_unlock(&devfreq->lock);
+
+ if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+ return;
+
+ cancel_delayed_work_sync(&devfreq->work);
+}
+EXPORT_SYMBOL(devfreq_monitor_suspend);
+
+/**
+ * devfreq_monitor_resume() - Resume load monitoring of a devfreq instance
+ * @devfreq: the devfreq instance.
+ *
+ * Helper function to resume devfreq device load monitoring. Function
+ * to be called from governor in response to DEVFREQ_GOV_RESUME
+ * event or when polling interval is set to non-zero.
+ */
+void devfreq_monitor_resume(struct devfreq *devfreq)
+{
+ unsigned long freq;
+
+ mutex_lock(&devfreq->lock);
+
+ if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+ goto out_update;
+
+ if (!devfreq->stop_polling)
+ goto out;
+
+ if (!delayed_work_pending(&devfreq->work) &&
+ devfreq->profile->polling_ms)
+ queue_delayed_work(devfreq_wq, &devfreq->work,
+ msecs_to_jiffies(devfreq->profile->polling_ms));
+
+out_update:
+ devfreq->stats.last_update = get_jiffies_64();
+ devfreq->stop_polling = false;
+
+ if (devfreq->profile->get_cur_freq &&
+ !devfreq->profile->get_cur_freq(devfreq->dev.parent, &freq))
+ devfreq->previous_freq = freq;
+
+out:
+ mutex_unlock(&devfreq->lock);
+}
+EXPORT_SYMBOL(devfreq_monitor_resume);
+
+/**
+ * devfreq_update_interval() - Update device devfreq monitoring interval
+ * @devfreq: the devfreq instance.
+ * @delay: new polling interval to be set.
+ *
+ * Helper function to set new load monitoring polling interval. Function
+ * to be called from governor in response to DEVFREQ_GOV_UPDATE_INTERVAL event.
+ */
+void devfreq_update_interval(struct devfreq *devfreq, unsigned int *delay)
+{
+ unsigned int cur_delay = devfreq->profile->polling_ms;
+ unsigned int new_delay = *delay;
+
+ mutex_lock(&devfreq->lock);
+ devfreq->profile->polling_ms = new_delay;
+
+ if (IS_SUPPORTED_FLAG(devfreq->governor->flags, IRQ_DRIVEN))
+ goto out;
+
+ if (devfreq->stop_polling)
+ goto out;
+
+ /* if new delay is zero, stop polling */
+ if (!new_delay) {
+ mutex_unlock(&devfreq->lock);
+ cancel_delayed_work_sync(&devfreq->work);
+ return;
+ }
+
+ /* if current delay is zero, start polling with new delay */
+ if (!cur_delay) {
+ queue_delayed_work(devfreq_wq, &devfreq->work,
+ msecs_to_jiffies(devfreq->profile->polling_ms));
+ goto out;
+ }
+
+ /* if current delay is greater than new delay, restart polling */
+ if (cur_delay > new_delay) {
+ mutex_unlock(&devfreq->lock);
+ cancel_delayed_work_sync(&devfreq->work);
+ mutex_lock(&devfreq->lock);
+ if (!devfreq->stop_polling)
+ queue_delayed_work(devfreq_wq, &devfreq->work,
+ msecs_to_jiffies(devfreq->profile->polling_ms));
+ }
+out:
+ mutex_unlock(&devfreq->lock);
+}
+EXPORT_SYMBOL(devfreq_update_interval);
+
+/**
+ * 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 err = -EINVAL;
+
+ mutex_lock(&devfreq->lock);
+
+ devfreq->scaling_min_freq = find_available_min_freq(devfreq);
+ if (!devfreq->scaling_min_freq)
+ goto out;
+
+ devfreq->scaling_max_freq = find_available_max_freq(devfreq);
+ if (!devfreq->scaling_max_freq) {
+ devfreq->scaling_max_freq = ULONG_MAX;
+ goto out;
+ }
+
+ err = update_devfreq(devfreq);
+
+out:
+ mutex_unlock(&devfreq->lock);
+ if (err)
+ dev_err(devfreq->dev.parent,
+ "failed to update frequency from OPP notifier (%d)\n",
+ err);
+
+ return NOTIFY_OK;
+}
+
+/**
+ * qos_notifier_call() - Common handler for QoS constraints.
+ * @devfreq: the devfreq instance.
+ */
+static int qos_notifier_call(struct devfreq *devfreq)
+{
+ int err;
+
+ mutex_lock(&devfreq->lock);
+ err = update_devfreq(devfreq);
+ mutex_unlock(&devfreq->lock);
+ if (err)
+ dev_err(devfreq->dev.parent,
+ "failed to update frequency from PM QoS (%d)\n",
+ err);
+
+ return NOTIFY_OK;
+}
+
+/**
+ * qos_min_notifier_call() - Callback for QoS min_freq changes.
+ * @nb: Should be devfreq->nb_min
+ * @val: not used
+ * @ptr: not used
+ */
+static int qos_min_notifier_call(struct notifier_block *nb,
+ unsigned long val, void *ptr)
+{
+ return qos_notifier_call(container_of(nb, struct devfreq, nb_min));
+}
+
+/**
+ * qos_max_notifier_call() - Callback for QoS max_freq changes.
+ * @nb: Should be devfreq->nb_max
+ * @val: not used
+ * @ptr: not used
+ */
+static int qos_max_notifier_call(struct notifier_block *nb,
+ unsigned long val, void *ptr)
+{
+ return qos_notifier_call(container_of(nb, struct devfreq, nb_max));
+}
+
+/**
+ * devfreq_dev_release() - Callback for struct device to release the device.
+ * @dev: the devfreq device
+ *
+ * Remove devfreq from the list and release its resources.
+ */
+static void devfreq_dev_release(struct device *dev)
+{
+ struct devfreq *devfreq = to_devfreq(dev);
+ int err;
+
+ mutex_lock(&devfreq_list_lock);
+ list_del(&devfreq->node);
+ mutex_unlock(&devfreq_list_lock);
+
+ err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_max,
+ DEV_PM_QOS_MAX_FREQUENCY);
+ if (err && err != -ENOENT)
+ dev_warn(dev->parent,
+ "Failed to remove max_freq notifier: %d\n", err);
+ err = dev_pm_qos_remove_notifier(devfreq->dev.parent, &devfreq->nb_min,
+ DEV_PM_QOS_MIN_FREQUENCY);
+ if (err && err != -ENOENT)
+ dev_warn(dev->parent,
+ "Failed to remove min_freq notifier: %d\n", err);
+
+ if (dev_pm_qos_request_active(&devfreq->user_max_freq_req)) {
+ err = dev_pm_qos_remove_request(&devfreq->user_max_freq_req);
+ if (err < 0)
+ dev_warn(dev->parent,
+ "Failed to remove max_freq request: %d\n", err);
+ }
+ if (dev_pm_qos_request_active(&devfreq->user_min_freq_req)) {
+ err = dev_pm_qos_remove_request(&devfreq->user_min_freq_req);
+ if (err < 0)
+ dev_warn(dev->parent,
+ "Failed to remove min_freq request: %d\n", err);
+ }
+
+ if (devfreq->profile->exit)
+ devfreq->profile->exit(devfreq->dev.parent);
+
+ if (devfreq->opp_table)
+ dev_pm_opp_put_opp_table(devfreq->opp_table);
+
+ mutex_destroy(&devfreq->lock);
+ srcu_cleanup_notifier_head(&devfreq->transition_notifier_list);
+ kfree(devfreq);
+}
+
+static void create_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov);
+static void remove_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov);
+
+/**
+ * devfreq_add_device() - Add devfreq feature to the device
+ * @dev: the device to add devfreq feature.
+ * @profile: device-specific profile to run devfreq.
+ * @governor_name: name of the policy to choose frequency.
+ * @data: devfreq driver pass to governors, governor should not change it.
+ */
+struct devfreq *devfreq_add_device(struct device *dev,
+ struct devfreq_dev_profile *profile,
+ const char *governor_name,
+ void *data)
+{
+ struct devfreq *devfreq;
+ struct devfreq_governor *governor;
+ unsigned long min_freq, max_freq;
+ int err = 0;
+
+ if (!dev || !profile || !governor_name) {
+ dev_err(dev, "%s: Invalid parameters.\n", __func__);
+ return ERR_PTR(-EINVAL);
+ }
+
+ mutex_lock(&devfreq_list_lock);
+ devfreq = find_device_devfreq(dev);
+ mutex_unlock(&devfreq_list_lock);
+ if (!IS_ERR(devfreq)) {
+ dev_err(dev, "%s: devfreq device already exists!\n",
+ __func__);
+ err = -EINVAL;
+ goto err_out;
+ }
+
+ devfreq = kzalloc(sizeof(struct devfreq), GFP_KERNEL);
+ if (!devfreq) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ mutex_init(&devfreq->lock);
+ mutex_lock(&devfreq->lock);
+ devfreq->dev.parent = dev;
+ devfreq->dev.class = devfreq_class;
+ devfreq->dev.release = devfreq_dev_release;
+ INIT_LIST_HEAD(&devfreq->node);
+ devfreq->profile = profile;
+ devfreq->previous_freq = profile->initial_freq;
+ devfreq->last_status.current_frequency = profile->initial_freq;
+ devfreq->data = data;
+ devfreq->nb.notifier_call = devfreq_notifier_call;
+
+ if (devfreq->profile->timer < 0
+ || devfreq->profile->timer >= DEVFREQ_TIMER_NUM) {
+ mutex_unlock(&devfreq->lock);
+ err = -EINVAL;
+ goto err_dev;
+ }
+
+ if (!devfreq->profile->max_state || !devfreq->profile->freq_table) {
+ mutex_unlock(&devfreq->lock);
+ err = set_freq_table(devfreq);
+ if (err < 0)
+ goto err_dev;
+ mutex_lock(&devfreq->lock);
+ } else {
+ devfreq->freq_table = devfreq->profile->freq_table;
+ devfreq->max_state = devfreq->profile->max_state;
+ }
+
+ devfreq->scaling_min_freq = find_available_min_freq(devfreq);
+ if (!devfreq->scaling_min_freq) {
+ mutex_unlock(&devfreq->lock);
+ err = -EINVAL;
+ goto err_dev;
+ }
+
+ devfreq->scaling_max_freq = find_available_max_freq(devfreq);
+ if (!devfreq->scaling_max_freq) {
+ mutex_unlock(&devfreq->lock);
+ err = -EINVAL;
+ goto err_dev;
+ }
+
+ devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+
+ devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
+ devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
+ if (IS_ERR(devfreq->opp_table))
+ devfreq->opp_table = NULL;
+
+ atomic_set(&devfreq->suspend_count, 0);
+
+ dev_set_name(&devfreq->dev, "%s", dev_name(dev));
+ err = device_register(&devfreq->dev);
+ if (err) {
+ mutex_unlock(&devfreq->lock);
+ put_device(&devfreq->dev);
+ goto err_out;
+ }
+
+ devfreq->stats.trans_table = devm_kzalloc(&devfreq->dev,
+ array3_size(sizeof(unsigned int),
+ devfreq->max_state,
+ devfreq->max_state),
+ GFP_KERNEL);
+ if (!devfreq->stats.trans_table) {
+ mutex_unlock(&devfreq->lock);
+ err = -ENOMEM;
+ goto err_devfreq;
+ }
+
+ devfreq->stats.time_in_state = devm_kcalloc(&devfreq->dev,
+ devfreq->max_state,
+ sizeof(*devfreq->stats.time_in_state),
+ GFP_KERNEL);
+ if (!devfreq->stats.time_in_state) {
+ mutex_unlock(&devfreq->lock);
+ err = -ENOMEM;
+ goto err_devfreq;
+ }
+
+ devfreq->stats.total_trans = 0;
+ devfreq->stats.last_update = get_jiffies_64();
+
+ srcu_init_notifier_head(&devfreq->transition_notifier_list);
+
+ mutex_unlock(&devfreq->lock);
+
+ err = dev_pm_qos_add_request(dev, &devfreq->user_min_freq_req,
+ DEV_PM_QOS_MIN_FREQUENCY, 0);
+ if (err < 0)
+ goto err_devfreq;
+ err = dev_pm_qos_add_request(dev, &devfreq->user_max_freq_req,
+ DEV_PM_QOS_MAX_FREQUENCY,
+ PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
+ if (err < 0)
+ goto err_devfreq;
+
+ devfreq->nb_min.notifier_call = qos_min_notifier_call;
+ err = dev_pm_qos_add_notifier(dev, &devfreq->nb_min,
+ DEV_PM_QOS_MIN_FREQUENCY);
+ if (err)
+ goto err_devfreq;
+
+ devfreq->nb_max.notifier_call = qos_max_notifier_call;
+ err = dev_pm_qos_add_notifier(dev, &devfreq->nb_max,
+ DEV_PM_QOS_MAX_FREQUENCY);
+ if (err)
+ goto err_devfreq;
+
+ mutex_lock(&devfreq_list_lock);
+
+ governor = try_then_request_governor(governor_name);
+ if (IS_ERR(governor)) {
+ dev_err(dev, "%s: Unable to find governor for the device\n",
+ __func__);
+ err = PTR_ERR(governor);
+ goto err_init;
+ }
+
+ devfreq->governor = governor;
+ err = devfreq->governor->event_handler(devfreq, DEVFREQ_GOV_START,
+ NULL);
+ if (err) {
+ dev_err_probe(dev, err,
+ "%s: Unable to start governor for the device\n",
+ __func__);
+ goto err_init;
+ }
+ create_sysfs_files(devfreq, devfreq->governor);
+
+ list_add(&devfreq->node, &devfreq_list);
+
+ mutex_unlock(&devfreq_list_lock);
+
+ if (devfreq->profile->is_cooling_device) {
+ devfreq->cdev = devfreq_cooling_em_register(devfreq, NULL);
+ if (IS_ERR(devfreq->cdev))
+ devfreq->cdev = NULL;
+ }
+
+ return devfreq;
+
+err_init:
+ mutex_unlock(&devfreq_list_lock);
+err_devfreq:
+ devfreq_remove_device(devfreq);
+ devfreq = NULL;
+err_dev:
+ kfree(devfreq);
+err_out:
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL(devfreq_add_device);
+
+/**
+ * devfreq_remove_device() - Remove devfreq feature from a device.
+ * @devfreq: the devfreq instance to be removed
+ *
+ * The opposite of devfreq_add_device().
+ */
+int devfreq_remove_device(struct devfreq *devfreq)
+{
+ if (!devfreq)
+ return -EINVAL;
+
+ devfreq_cooling_unregister(devfreq->cdev);
+
+ if (devfreq->governor) {
+ devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_STOP, NULL);
+ remove_sysfs_files(devfreq, devfreq->governor);
+ }
+
+ device_unregister(&devfreq->dev);
+
+ return 0;
+}
+EXPORT_SYMBOL(devfreq_remove_device);
+
+static int devm_devfreq_dev_match(struct device *dev, void *res, void *data)
+{
+ struct devfreq **r = res;
+
+ if (WARN_ON(!r || !*r))
+ return 0;
+
+ return *r == data;
+}
+
+static void devm_devfreq_dev_release(struct device *dev, void *res)
+{
+ devfreq_remove_device(*(struct devfreq **)res);
+}
+
+/**
+ * devm_devfreq_add_device() - Resource-managed devfreq_add_device()
+ * @dev: the device to add devfreq feature.
+ * @profile: device-specific profile to run devfreq.
+ * @governor_name: name of the policy to choose frequency.
+ * @data: devfreq driver pass to governors, governor should not change it.
+ *
+ * This function manages automatically the memory of devfreq device using device
+ * resource management and simplify the free operation for memory of devfreq
+ * device.
+ */
+struct devfreq *devm_devfreq_add_device(struct device *dev,
+ struct devfreq_dev_profile *profile,
+ const char *governor_name,
+ void *data)
+{
+ struct devfreq **ptr, *devfreq;
+
+ ptr = devres_alloc(devm_devfreq_dev_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return ERR_PTR(-ENOMEM);
+
+ devfreq = devfreq_add_device(dev, profile, governor_name, data);
+ if (IS_ERR(devfreq)) {
+ devres_free(ptr);
+ return devfreq;
+ }
+
+ *ptr = devfreq;
+ devres_add(dev, ptr);
+
+ return devfreq;
+}
+EXPORT_SYMBOL(devm_devfreq_add_device);
+
+#ifdef CONFIG_OF
+/*
+ * devfreq_get_devfreq_by_node - Get the devfreq device from devicetree
+ * @node - pointer to device_node
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+ struct devfreq *devfreq;
+
+ if (!node)
+ return ERR_PTR(-EINVAL);
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ if (devfreq->dev.parent
+ && devfreq->dev.parent->of_node == node) {
+ mutex_unlock(&devfreq_list_lock);
+ return devfreq;
+ }
+ }
+ mutex_unlock(&devfreq_list_lock);
+
+ return ERR_PTR(-ENODEV);
+}
+
+/*
+ * devfreq_get_devfreq_by_phandle - Get the devfreq device from devicetree
+ * @dev - instance to the given device
+ * @phandle_name - name of property holding a phandle value
+ * @index - index into list of devfreq
+ *
+ * return the instance of devfreq device
+ */
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+ const char *phandle_name, int index)
+{
+ struct device_node *node;
+ struct devfreq *devfreq;
+
+ if (!dev || !phandle_name)
+ return ERR_PTR(-EINVAL);
+
+ if (!dev->of_node)
+ return ERR_PTR(-EINVAL);
+
+ node = of_parse_phandle(dev->of_node, phandle_name, index);
+ if (!node)
+ return ERR_PTR(-ENODEV);
+
+ devfreq = devfreq_get_devfreq_by_node(node);
+ of_node_put(node);
+
+ return devfreq;
+}
+
+#else
+struct devfreq *devfreq_get_devfreq_by_node(struct device_node *node)
+{
+ return ERR_PTR(-ENODEV);
+}
+
+struct devfreq *devfreq_get_devfreq_by_phandle(struct device *dev,
+ const char *phandle_name, int index)
+{
+ return ERR_PTR(-ENODEV);
+}
+#endif /* CONFIG_OF */
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_node);
+EXPORT_SYMBOL_GPL(devfreq_get_devfreq_by_phandle);
+
+/**
+ * devm_devfreq_remove_device() - Resource-managed devfreq_remove_device()
+ * @dev: the device from which to remove devfreq feature.
+ * @devfreq: the devfreq instance to be removed
+ */
+void devm_devfreq_remove_device(struct device *dev, struct devfreq *devfreq)
+{
+ WARN_ON(devres_release(dev, devm_devfreq_dev_release,
+ devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_remove_device);
+
+/**
+ * devfreq_suspend_device() - Suspend devfreq of a device.
+ * @devfreq: the devfreq instance to be suspended
+ *
+ * This function is intended to be called by the pm callbacks
+ * (e.g., runtime_suspend, suspend) of the device driver that
+ * holds the devfreq.
+ */
+int devfreq_suspend_device(struct devfreq *devfreq)
+{
+ int ret;
+
+ if (!devfreq)
+ return -EINVAL;
+
+ if (atomic_inc_return(&devfreq->suspend_count) > 1)
+ return 0;
+
+ if (devfreq->governor) {
+ ret = devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_SUSPEND, NULL);
+ if (ret)
+ return ret;
+ }
+
+ if (devfreq->suspend_freq) {
+ mutex_lock(&devfreq->lock);
+ ret = devfreq_set_target(devfreq, devfreq->suspend_freq, 0);
+ mutex_unlock(&devfreq->lock);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(devfreq_suspend_device);
+
+/**
+ * devfreq_resume_device() - Resume devfreq of a device.
+ * @devfreq: the devfreq instance to be resumed
+ *
+ * This function is intended to be called by the pm callbacks
+ * (e.g., runtime_resume, resume) of the device driver that
+ * holds the devfreq.
+ */
+int devfreq_resume_device(struct devfreq *devfreq)
+{
+ int ret;
+
+ if (!devfreq)
+ return -EINVAL;
+
+ if (atomic_dec_return(&devfreq->suspend_count) >= 1)
+ return 0;
+
+ if (devfreq->resume_freq) {
+ mutex_lock(&devfreq->lock);
+ ret = devfreq_set_target(devfreq, devfreq->resume_freq, 0);
+ mutex_unlock(&devfreq->lock);
+ if (ret)
+ return ret;
+ }
+
+ if (devfreq->governor) {
+ ret = devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_RESUME, NULL);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(devfreq_resume_device);
+
+/**
+ * devfreq_suspend() - Suspend devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycles for suspending governors
+ * and devices preserving the state for resume. On some platforms the devfreq
+ * device must have precise state (frequency) after resume in order to provide
+ * fully operating setup.
+ */
+void devfreq_suspend(void)
+{
+ struct devfreq *devfreq;
+ int ret;
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ ret = devfreq_suspend_device(devfreq);
+ if (ret)
+ dev_err(&devfreq->dev,
+ "failed to suspend devfreq device\n");
+ }
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_resume() - Resume devfreq governors and devices
+ *
+ * Called during system wide Suspend/Hibernate cycle for resuming governors and
+ * devices that are suspended with devfreq_suspend().
+ */
+void devfreq_resume(void)
+{
+ struct devfreq *devfreq;
+ int ret;
+
+ mutex_lock(&devfreq_list_lock);
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ ret = devfreq_resume_device(devfreq);
+ if (ret)
+ dev_warn(&devfreq->dev,
+ "failed to resume devfreq device\n");
+ }
+ mutex_unlock(&devfreq_list_lock);
+}
+
+/**
+ * devfreq_add_governor() - Add devfreq governor
+ * @governor: the devfreq governor to be added
+ */
+int devfreq_add_governor(struct devfreq_governor *governor)
+{
+ struct devfreq_governor *g;
+ struct devfreq *devfreq;
+ int err = 0;
+
+ if (!governor) {
+ pr_err("%s: Invalid parameters.\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&devfreq_list_lock);
+ g = find_devfreq_governor(governor->name);
+ if (!IS_ERR(g)) {
+ pr_err("%s: governor %s already registered\n", __func__,
+ g->name);
+ err = -EINVAL;
+ goto err_out;
+ }
+
+ list_add(&governor->node, &devfreq_governor_list);
+
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ int ret = 0;
+ struct device *dev = devfreq->dev.parent;
+
+ if (!strncmp(devfreq->governor->name, governor->name,
+ DEVFREQ_NAME_LEN)) {
+ /* The following should never occur */
+ if (devfreq->governor) {
+ dev_warn(dev,
+ "%s: Governor %s already present\n",
+ __func__, devfreq->governor->name);
+ ret = devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_STOP, NULL);
+ if (ret) {
+ dev_warn(dev,
+ "%s: Governor %s stop = %d\n",
+ __func__,
+ devfreq->governor->name, ret);
+ }
+ /* Fall through */
+ }
+ devfreq->governor = governor;
+ ret = devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_START, NULL);
+ if (ret) {
+ dev_warn(dev, "%s: Governor %s start=%d\n",
+ __func__, devfreq->governor->name,
+ ret);
+ }
+ }
+ }
+
+err_out:
+ mutex_unlock(&devfreq_list_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(devfreq_add_governor);
+
+static void devm_devfreq_remove_governor(void *governor)
+{
+ WARN_ON(devfreq_remove_governor(governor));
+}
+
+/**
+ * devm_devfreq_add_governor() - Add devfreq governor
+ * @dev: device which adds devfreq governor
+ * @governor: the devfreq governor to be added
+ *
+ * This is a resource-managed variant of devfreq_add_governor().
+ */
+int devm_devfreq_add_governor(struct device *dev,
+ struct devfreq_governor *governor)
+{
+ int err;
+
+ err = devfreq_add_governor(governor);
+ if (err)
+ return err;
+
+ return devm_add_action_or_reset(dev, devm_devfreq_remove_governor,
+ governor);
+}
+EXPORT_SYMBOL(devm_devfreq_add_governor);
+
+/**
+ * devfreq_remove_governor() - Remove devfreq feature from a device.
+ * @governor: the devfreq governor to be removed
+ */
+int devfreq_remove_governor(struct devfreq_governor *governor)
+{
+ struct devfreq_governor *g;
+ struct devfreq *devfreq;
+ int err = 0;
+
+ if (!governor) {
+ pr_err("%s: Invalid parameters.\n", __func__);
+ return -EINVAL;
+ }
+
+ mutex_lock(&devfreq_list_lock);
+ g = find_devfreq_governor(governor->name);
+ if (IS_ERR(g)) {
+ pr_err("%s: governor %s not registered\n", __func__,
+ governor->name);
+ err = PTR_ERR(g);
+ goto err_out;
+ }
+ list_for_each_entry(devfreq, &devfreq_list, node) {
+ int ret;
+ struct device *dev = devfreq->dev.parent;
+
+ if (!strncmp(devfreq->governor->name, governor->name,
+ DEVFREQ_NAME_LEN)) {
+ /* we should have a devfreq governor! */
+ if (!devfreq->governor) {
+ dev_warn(dev, "%s: Governor %s NOT present\n",
+ __func__, governor->name);
+ continue;
+ /* Fall through */
+ }
+ ret = devfreq->governor->event_handler(devfreq,
+ DEVFREQ_GOV_STOP, NULL);
+ if (ret) {
+ dev_warn(dev, "%s: Governor %s stop=%d\n",
+ __func__, devfreq->governor->name,
+ ret);
+ }
+ devfreq->governor = NULL;
+ }
+ }
+
+ list_del(&governor->node);
+err_out:
+ mutex_unlock(&devfreq_list_lock);
+
+ return err;
+}
+EXPORT_SYMBOL(devfreq_remove_governor);
+
+static ssize_t name_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+ return sprintf(buf, "%s\n", dev_name(df->dev.parent));
+}
+static DEVICE_ATTR_RO(name);
+
+static ssize_t governor_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+
+ if (!df->governor)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", df->governor->name);
+}
+
+static ssize_t governor_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ int ret;
+ char str_governor[DEVFREQ_NAME_LEN + 1];
+ const struct devfreq_governor *governor, *prev_governor;
+
+ if (!df->governor)
+ return -EINVAL;
+
+ ret = sscanf(buf, "%" __stringify(DEVFREQ_NAME_LEN) "s", str_governor);
+ if (ret != 1)
+ return -EINVAL;
+
+ mutex_lock(&devfreq_list_lock);
+ governor = try_then_request_governor(str_governor);
+ if (IS_ERR(governor)) {
+ ret = PTR_ERR(governor);
+ goto out;
+ }
+ if (df->governor == governor) {
+ ret = 0;
+ goto out;
+ } else if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)
+ || IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE)) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ /*
+ * Stop the current governor and remove the specific sysfs files
+ * which depend on current governor.
+ */
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
+ if (ret) {
+ dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
+ __func__, df->governor->name, ret);
+ goto out;
+ }
+ remove_sysfs_files(df, df->governor);
+
+ /*
+ * Start the new governor and create the specific sysfs files
+ * which depend on the new governor.
+ */
+ prev_governor = df->governor;
+ df->governor = governor;
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+ if (ret) {
+ dev_warn(dev, "%s: Governor %s not started(%d)\n",
+ __func__, df->governor->name, ret);
+
+ /* Restore previous governor */
+ df->governor = prev_governor;
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+ if (ret) {
+ dev_err(dev,
+ "%s: reverting to Governor %s failed (%d)\n",
+ __func__, prev_governor->name, ret);
+ df->governor = NULL;
+ goto out;
+ }
+ }
+
+ /*
+ * Create the sysfs files for the new governor. But if failed to start
+ * the new governor, restore the sysfs files of previous governor.
+ */
+ create_sysfs_files(df, df->governor);
+
+out:
+ mutex_unlock(&devfreq_list_lock);
+
+ if (!ret)
+ ret = count;
+ return ret;
+}
+static DEVICE_ATTR_RW(governor);
+
+static ssize_t available_governors_show(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(d);
+ ssize_t count = 0;
+
+ if (!df->governor)
+ return -EINVAL;
+
+ mutex_lock(&devfreq_list_lock);
+
+ /*
+ * The devfreq with immutable governor (e.g., passive) shows
+ * only own governor.
+ */
+ if (IS_SUPPORTED_FLAG(df->governor->flags, IMMUTABLE)) {
+ count = scnprintf(&buf[count], DEVFREQ_NAME_LEN,
+ "%s ", df->governor->name);
+ /*
+ * The devfreq device shows the registered governor except for
+ * immutable governors such as passive governor .
+ */
+ } else {
+ struct devfreq_governor *governor;
+
+ list_for_each_entry(governor, &devfreq_governor_list, node) {
+ if (IS_SUPPORTED_FLAG(governor->flags, IMMUTABLE))
+ continue;
+ count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+ "%s ", governor->name);
+ }
+ }
+
+ mutex_unlock(&devfreq_list_lock);
+
+ /* Truncate the trailing space */
+ if (count)
+ count--;
+
+ count += sprintf(&buf[count], "\n");
+
+ return count;
+}
+static DEVICE_ATTR_RO(available_governors);
+
+static ssize_t cur_freq_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ unsigned long freq;
+ struct devfreq *df = to_devfreq(dev);
+
+ if (!df->profile)
+ return -EINVAL;
+
+ if (df->profile->get_cur_freq &&
+ !df->profile->get_cur_freq(df->dev.parent, &freq))
+ return sprintf(buf, "%lu\n", freq);
+
+ return sprintf(buf, "%lu\n", df->previous_freq);
+}
+static DEVICE_ATTR_RO(cur_freq);
+
+static ssize_t target_freq_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+
+ return sprintf(buf, "%lu\n", df->previous_freq);
+}
+static DEVICE_ATTR_RO(target_freq);
+
+static ssize_t min_freq_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+
+ /*
+ * Protect against theoretical sysfs writes between
+ * device_add and dev_pm_qos_add_request
+ */
+ if (!dev_pm_qos_request_active(&df->user_min_freq_req))
+ return -EAGAIN;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ return -EINVAL;
+
+ /* Round down to kHz for PM QoS */
+ ret = dev_pm_qos_update_request(&df->user_min_freq_req,
+ value / HZ_PER_KHZ);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static ssize_t min_freq_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long min_freq, max_freq;
+
+ mutex_lock(&df->lock);
+ devfreq_get_freq_range(df, &min_freq, &max_freq);
+ mutex_unlock(&df->lock);
+
+ return sprintf(buf, "%lu\n", min_freq);
+}
+static DEVICE_ATTR_RW(min_freq);
+
+static ssize_t max_freq_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long value;
+ int ret;
+
+ /*
+ * Protect against theoretical sysfs writes between
+ * device_add and dev_pm_qos_add_request
+ */
+ if (!dev_pm_qos_request_active(&df->user_max_freq_req))
+ return -EINVAL;
+
+ ret = sscanf(buf, "%lu", &value);
+ if (ret != 1)
+ return -EINVAL;
+
+ /*
+ * PM QoS frequencies are in kHz so we need to convert. Convert by
+ * rounding upwards so that the acceptable interval never shrinks.
+ *
+ * For example if the user writes "666666666" to sysfs this value will
+ * be converted to 666667 kHz and back to 666667000 Hz before an OPP
+ * lookup, this ensures that an OPP of 666666666Hz is still accepted.
+ *
+ * A value of zero means "no limit".
+ */
+ if (value)
+ value = DIV_ROUND_UP(value, HZ_PER_KHZ);
+ else
+ value = PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
+
+ ret = dev_pm_qos_update_request(&df->user_max_freq_req, value);
+ if (ret < 0)
+ return ret;
+
+ return count;
+}
+
+static ssize_t max_freq_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned long min_freq, max_freq;
+
+ mutex_lock(&df->lock);
+ devfreq_get_freq_range(df, &min_freq, &max_freq);
+ mutex_unlock(&df->lock);
+
+ return sprintf(buf, "%lu\n", max_freq);
+}
+static DEVICE_ATTR_RW(max_freq);
+
+static ssize_t available_frequencies_show(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *df = to_devfreq(d);
+ ssize_t count = 0;
+ int i;
+
+ if (!df->profile)
+ return -EINVAL;
+
+ mutex_lock(&df->lock);
+
+ for (i = 0; i < df->max_state; i++)
+ count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
+ "%lu ", df->freq_table[i]);
+
+ mutex_unlock(&df->lock);
+ /* Truncate the trailing space */
+ if (count)
+ count--;
+
+ count += sprintf(&buf[count], "\n");
+
+ return count;
+}
+static DEVICE_ATTR_RO(available_frequencies);
+
+static ssize_t trans_stat_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+ ssize_t len = 0;
+ int i, j;
+ unsigned int max_state;
+
+ if (!df->profile)
+ return -EINVAL;
+ max_state = df->max_state;
+
+ if (max_state == 0)
+ return scnprintf(buf, PAGE_SIZE, "Not Supported.\n");
+
+ mutex_lock(&df->lock);
+ if (!df->stop_polling &&
+ devfreq_update_status(df, df->previous_freq)) {
+ mutex_unlock(&df->lock);
+ return 0;
+ }
+ mutex_unlock(&df->lock);
+
+ len += scnprintf(buf + len, PAGE_SIZE - len, " From : To\n");
+ len += scnprintf(buf + len, PAGE_SIZE - len, " :");
+ for (i = 0; i < max_state; i++) {
+ if (len >= PAGE_SIZE - 1)
+ break;
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu",
+ df->freq_table[i]);
+ }
+ if (len >= PAGE_SIZE - 1)
+ return PAGE_SIZE - 1;
+
+ len += scnprintf(buf + len, PAGE_SIZE - len, " time(ms)\n");
+
+ for (i = 0; i < max_state; i++) {
+ if (len >= PAGE_SIZE - 1)
+ break;
+ if (df->freq_table[i] == df->previous_freq)
+ len += scnprintf(buf + len, PAGE_SIZE - len, "*");
+ else
+ len += scnprintf(buf + len, PAGE_SIZE - len, " ");
+ if (len >= PAGE_SIZE - 1)
+ break;
+
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%10lu:",
+ df->freq_table[i]);
+ for (j = 0; j < max_state; j++) {
+ if (len >= PAGE_SIZE - 1)
+ break;
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%10u",
+ df->stats.trans_table[(i * max_state) + j]);
+ }
+ if (len >= PAGE_SIZE - 1)
+ break;
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%10llu\n", (u64)
+ jiffies64_to_msecs(df->stats.time_in_state[i]));
+ }
+
+ if (len < PAGE_SIZE - 1)
+ len += scnprintf(buf + len, PAGE_SIZE - len, "Total transition : %u\n",
+ df->stats.total_trans);
+
+ if (len >= PAGE_SIZE - 1) {
+ pr_warn_once("devfreq transition table exceeds PAGE_SIZE. Disabling\n");
+ return -EFBIG;
+ }
+
+ return len;
+}
+
+static ssize_t trans_stat_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ int err, value;
+
+ if (!df->profile)
+ return -EINVAL;
+
+ if (df->max_state == 0)
+ return count;
+
+ err = kstrtoint(buf, 10, &value);
+ if (err || value != 0)
+ return -EINVAL;
+
+ mutex_lock(&df->lock);
+ memset(df->stats.time_in_state, 0, (df->max_state *
+ sizeof(*df->stats.time_in_state)));
+ memset(df->stats.trans_table, 0, array3_size(sizeof(unsigned int),
+ df->max_state,
+ df->max_state));
+ df->stats.total_trans = 0;
+ df->stats.last_update = get_jiffies_64();
+ mutex_unlock(&df->lock);
+
+ return count;
+}
+static DEVICE_ATTR_RW(trans_stat);
+
+static struct attribute *devfreq_attrs[] = {
+ &dev_attr_name.attr,
+ &dev_attr_governor.attr,
+ &dev_attr_available_governors.attr,
+ &dev_attr_cur_freq.attr,
+ &dev_attr_available_frequencies.attr,
+ &dev_attr_target_freq.attr,
+ &dev_attr_min_freq.attr,
+ &dev_attr_max_freq.attr,
+ &dev_attr_trans_stat.attr,
+ NULL,
+};
+ATTRIBUTE_GROUPS(devfreq);
+
+static ssize_t polling_interval_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+
+ if (!df->profile)
+ return -EINVAL;
+
+ return sprintf(buf, "%d\n", df->profile->polling_ms);
+}
+
+static ssize_t polling_interval_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ unsigned int value;
+ int ret;
+
+ if (!df->governor)
+ return -EINVAL;
+
+ ret = sscanf(buf, "%u", &value);
+ if (ret != 1)
+ return -EINVAL;
+
+ df->governor->event_handler(df, DEVFREQ_GOV_UPDATE_INTERVAL, &value);
+ ret = count;
+
+ return ret;
+}
+static DEVICE_ATTR_RW(polling_interval);
+
+static ssize_t timer_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct devfreq *df = to_devfreq(dev);
+
+ if (!df->profile)
+ return -EINVAL;
+
+ return sprintf(buf, "%s\n", timer_name[df->profile->timer]);
+}
+
+static ssize_t timer_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *df = to_devfreq(dev);
+ char str_timer[DEVFREQ_NAME_LEN + 1];
+ int timer = -1;
+ int ret = 0, i;
+
+ if (!df->governor || !df->profile)
+ return -EINVAL;
+
+ ret = sscanf(buf, "%16s", str_timer);
+ if (ret != 1)
+ return -EINVAL;
+
+ for (i = 0; i < DEVFREQ_TIMER_NUM; i++) {
+ if (!strncmp(timer_name[i], str_timer, DEVFREQ_NAME_LEN)) {
+ timer = i;
+ break;
+ }
+ }
+
+ if (timer < 0) {
+ ret = -EINVAL;
+ goto out;
+ }
+
+ if (df->profile->timer == timer) {
+ ret = 0;
+ goto out;
+ }
+
+ mutex_lock(&df->lock);
+ df->profile->timer = timer;
+ mutex_unlock(&df->lock);
+
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_STOP, NULL);
+ if (ret) {
+ dev_warn(dev, "%s: Governor %s not stopped(%d)\n",
+ __func__, df->governor->name, ret);
+ goto out;
+ }
+
+ ret = df->governor->event_handler(df, DEVFREQ_GOV_START, NULL);
+ if (ret)
+ dev_warn(dev, "%s: Governor %s not started(%d)\n",
+ __func__, df->governor->name, ret);
+out:
+ return ret ? ret : count;
+}
+static DEVICE_ATTR_RW(timer);
+
+#define CREATE_SYSFS_FILE(df, name) \
+{ \
+ int ret; \
+ ret = sysfs_create_file(&df->dev.kobj, &dev_attr_##name.attr); \
+ if (ret < 0) { \
+ dev_warn(&df->dev, \
+ "Unable to create attr(%s)\n", "##name"); \
+ } \
+} \
+
+/* Create the specific sysfs files which depend on each governor. */
+static void create_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov)
+{
+ if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+ CREATE_SYSFS_FILE(devfreq, polling_interval);
+ if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+ CREATE_SYSFS_FILE(devfreq, timer);
+}
+
+/* Remove the specific sysfs files which depend on each governor. */
+static void remove_sysfs_files(struct devfreq *devfreq,
+ const struct devfreq_governor *gov)
+{
+ if (IS_SUPPORTED_ATTR(gov->attrs, POLLING_INTERVAL))
+ sysfs_remove_file(&devfreq->dev.kobj,
+ &dev_attr_polling_interval.attr);
+ if (IS_SUPPORTED_ATTR(gov->attrs, TIMER))
+ sysfs_remove_file(&devfreq->dev.kobj, &dev_attr_timer.attr);
+}
+
+/**
+ * devfreq_summary_show() - Show the summary of the devfreq devices
+ * @s: seq_file instance to show the summary of devfreq devices
+ * @data: not used
+ *
+ * Show the summary of the devfreq devices via 'devfreq_summary' debugfs file.
+ * It helps that user can know the detailed information of the devfreq devices.
+ *
+ * Return 0 always because it shows the information without any data change.
+ */
+static int devfreq_summary_show(struct seq_file *s, void *data)
+{
+ struct devfreq *devfreq;
+ struct devfreq *p_devfreq = NULL;
+ unsigned long cur_freq, min_freq, max_freq;
+ unsigned int polling_ms;
+ unsigned int timer;
+
+ seq_printf(s, "%-30s %-30s %-15s %-10s %10s %12s %12s %12s\n",
+ "dev",
+ "parent_dev",
+ "governor",
+ "timer",
+ "polling_ms",
+ "cur_freq_Hz",
+ "min_freq_Hz",
+ "max_freq_Hz");
+ seq_printf(s, "%30s %30s %15s %10s %10s %12s %12s %12s\n",
+ "------------------------------",
+ "------------------------------",
+ "---------------",
+ "----------",
+ "----------",
+ "------------",
+ "------------",
+ "------------");
+
+ mutex_lock(&devfreq_list_lock);
+
+ list_for_each_entry_reverse(devfreq, &devfreq_list, node) {
+#if IS_ENABLED(CONFIG_DEVFREQ_GOV_PASSIVE)
+ if (!strncmp(devfreq->governor->name, DEVFREQ_GOV_PASSIVE,
+ DEVFREQ_NAME_LEN)) {
+ struct devfreq_passive_data *data = devfreq->data;
+
+ if (data)
+ p_devfreq = data->parent;
+ } else {
+ p_devfreq = NULL;
+ }
+#endif
+
+ mutex_lock(&devfreq->lock);
+ cur_freq = devfreq->previous_freq;
+ devfreq_get_freq_range(devfreq, &min_freq, &max_freq);
+ timer = devfreq->profile->timer;
+
+ if (IS_SUPPORTED_ATTR(devfreq->governor->attrs, POLLING_INTERVAL))
+ polling_ms = devfreq->profile->polling_ms;
+ else
+ polling_ms = 0;
+ mutex_unlock(&devfreq->lock);
+
+ seq_printf(s,
+ "%-30s %-30s %-15s %-10s %10d %12ld %12ld %12ld\n",
+ dev_name(&devfreq->dev),
+ p_devfreq ? dev_name(&p_devfreq->dev) : "null",
+ devfreq->governor->name,
+ polling_ms ? timer_name[timer] : "null",
+ polling_ms,
+ cur_freq,
+ min_freq,
+ max_freq);
+ }
+
+ mutex_unlock(&devfreq_list_lock);
+
+ return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(devfreq_summary);
+
+static int __init devfreq_init(void)
+{
+ devfreq_class = class_create(THIS_MODULE, "devfreq");
+ if (IS_ERR(devfreq_class)) {
+ pr_err("%s: couldn't create class\n", __FILE__);
+ return PTR_ERR(devfreq_class);
+ }
+
+ devfreq_wq = create_freezable_workqueue("devfreq_wq");
+ if (!devfreq_wq) {
+ class_destroy(devfreq_class);
+ pr_err("%s: couldn't create workqueue\n", __FILE__);
+ return -ENOMEM;
+ }
+ devfreq_class->dev_groups = devfreq_groups;
+
+ devfreq_debugfs = debugfs_create_dir("devfreq", NULL);
+ debugfs_create_file("devfreq_summary", 0444,
+ devfreq_debugfs, NULL,
+ &devfreq_summary_fops);
+
+ return 0;
+}
+subsys_initcall(devfreq_init);
+
+/*
+ * The following are helper functions for devfreq user device drivers with
+ * OPP framework.
+ */
+
+/**
+ * devfreq_recommended_opp() - Helper function to get proper OPP for the
+ * freq value given to target callback.
+ * @dev: The devfreq user device. (parent of devfreq)
+ * @freq: The frequency given to target function
+ * @flags: Flags handed from devfreq framework.
+ *
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
+ */
+struct dev_pm_opp *devfreq_recommended_opp(struct device *dev,
+ unsigned long *freq,
+ u32 flags)
+{
+ struct dev_pm_opp *opp;
+
+ if (flags & DEVFREQ_FLAG_LEAST_UPPER_BOUND) {
+ /* The freq is an upper bound. opp should be lower */
+ opp = dev_pm_opp_find_freq_floor(dev, freq);
+
+ /* If not available, use the closest opp */
+ if (opp == ERR_PTR(-ERANGE))
+ opp = dev_pm_opp_find_freq_ceil(dev, freq);
+ } else {
+ /* The freq is an lower bound. opp should be higher */
+ opp = dev_pm_opp_find_freq_ceil(dev, freq);
+
+ /* If not available, use the closest opp */
+ if (opp == ERR_PTR(-ERANGE))
+ opp = dev_pm_opp_find_freq_floor(dev, freq);
+ }
+
+ return opp;
+}
+EXPORT_SYMBOL(devfreq_recommended_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)
+{
+ return dev_pm_opp_register_notifier(dev, &devfreq->nb);
+}
+EXPORT_SYMBOL(devfreq_register_opp_notifier);
+
+/**
+ * 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)
+{
+ return dev_pm_opp_unregister_notifier(dev, &devfreq->nb);
+}
+EXPORT_SYMBOL(devfreq_unregister_opp_notifier);
+
+static void devm_devfreq_opp_release(struct device *dev, void *res)
+{
+ devfreq_unregister_opp_notifier(dev, *(struct devfreq **)res);
+}
+
+/**
+ * devm_devfreq_register_opp_notifier() - Resource-managed
+ * devfreq_register_opp_notifier()
+ * @dev: The devfreq user device. (parent of devfreq)
+ * @devfreq: The devfreq object.
+ */
+int devm_devfreq_register_opp_notifier(struct device *dev,
+ struct devfreq *devfreq)
+{
+ struct devfreq **ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_devfreq_opp_release, sizeof(*ptr), GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ ret = devfreq_register_opp_notifier(dev, devfreq);
+ if (ret) {
+ devres_free(ptr);
+ return ret;
+ }
+
+ *ptr = devfreq;
+ devres_add(dev, ptr);
+
+ return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_opp_notifier);
+
+/**
+ * devm_devfreq_unregister_opp_notifier() - Resource-managed
+ * devfreq_unregister_opp_notifier()
+ * @dev: The devfreq user device. (parent of devfreq)
+ * @devfreq: The devfreq object.
+ */
+void devm_devfreq_unregister_opp_notifier(struct device *dev,
+ struct devfreq *devfreq)
+{
+ WARN_ON(devres_release(dev, devm_devfreq_opp_release,
+ devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_opp_notifier);
+
+/**
+ * devfreq_register_notifier() - Register a driver with devfreq
+ * @devfreq: The devfreq object.
+ * @nb: The notifier block to register.
+ * @list: DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_register_notifier(struct devfreq *devfreq,
+ struct notifier_block *nb,
+ unsigned int list)
+{
+ int ret = 0;
+
+ if (!devfreq)
+ return -EINVAL;
+
+ switch (list) {
+ case DEVFREQ_TRANSITION_NOTIFIER:
+ ret = srcu_notifier_chain_register(
+ &devfreq->transition_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(devfreq_register_notifier);
+
+/*
+ * devfreq_unregister_notifier() - Unregister a driver with devfreq
+ * @devfreq: The devfreq object.
+ * @nb: The notifier block to be unregistered.
+ * @list: DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devfreq_unregister_notifier(struct devfreq *devfreq,
+ struct notifier_block *nb,
+ unsigned int list)
+{
+ int ret = 0;
+
+ if (!devfreq)
+ return -EINVAL;
+
+ switch (list) {
+ case DEVFREQ_TRANSITION_NOTIFIER:
+ ret = srcu_notifier_chain_unregister(
+ &devfreq->transition_notifier_list, nb);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(devfreq_unregister_notifier);
+
+struct devfreq_notifier_devres {
+ struct devfreq *devfreq;
+ struct notifier_block *nb;
+ unsigned int list;
+};
+
+static void devm_devfreq_notifier_release(struct device *dev, void *res)
+{
+ struct devfreq_notifier_devres *this = res;
+
+ devfreq_unregister_notifier(this->devfreq, this->nb, this->list);
+}
+
+/**
+ * devm_devfreq_register_notifier()
+ * - Resource-managed devfreq_register_notifier()
+ * @dev: The devfreq user device. (parent of devfreq)
+ * @devfreq: The devfreq object.
+ * @nb: The notifier block to be unregistered.
+ * @list: DEVFREQ_TRANSITION_NOTIFIER.
+ */
+int devm_devfreq_register_notifier(struct device *dev,
+ struct devfreq *devfreq,
+ struct notifier_block *nb,
+ unsigned int list)
+{
+ struct devfreq_notifier_devres *ptr;
+ int ret;
+
+ ptr = devres_alloc(devm_devfreq_notifier_release, sizeof(*ptr),
+ GFP_KERNEL);
+ if (!ptr)
+ return -ENOMEM;
+
+ ret = devfreq_register_notifier(devfreq, nb, list);
+ if (ret) {
+ devres_free(ptr);
+ return ret;
+ }
+
+ ptr->devfreq = devfreq;
+ ptr->nb = nb;
+ ptr->list = list;
+ devres_add(dev, ptr);
+
+ return 0;
+}
+EXPORT_SYMBOL(devm_devfreq_register_notifier);
+
+/**
+ * devm_devfreq_unregister_notifier()
+ * - Resource-managed devfreq_unregister_notifier()
+ * @dev: The devfreq user device. (parent of devfreq)
+ * @devfreq: The devfreq object.
+ * @nb: The notifier block to be unregistered.
+ * @list: DEVFREQ_TRANSITION_NOTIFIER.
+ */
+void devm_devfreq_unregister_notifier(struct device *dev,
+ struct devfreq *devfreq,
+ struct notifier_block *nb,
+ unsigned int list)
+{
+ WARN_ON(devres_release(dev, devm_devfreq_notifier_release,
+ devm_devfreq_dev_match, devfreq));
+}
+EXPORT_SYMBOL(devm_devfreq_unregister_notifier);