1 files changed, 1300 insertions, 0 deletions

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
new file mode 100644
index 000000000000..d5c1149ff123
--- /dev/null
+++ b/drivers/base/power/opp/core.c
@@ -0,0 +1,1300 @@
+/*
+ * Generic OPP Interface
+ *
+ * Copyright (C) 2009-2010 Texas Instruments Incorporated.
+ *      Nishanth Menon
+ *      Romit Dasgupta
+ *      Kevin Hilman
+ *
+ * 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/err.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/of.h>
+#include <linux/export.h>
+
+#include "opp.h"
+
+/*
+ * The root of the list of all devices. All device_opp structures branch off
+ * from here, with each device_opp containing the list of opp it supports in
+ * various states of availability.
+ */
+static LIST_HEAD(dev_opp_list);
+/* Lock to allow exclusive modification to the device and opp lists */
+static DEFINE_MUTEX(dev_opp_list_lock);
+
+#define opp_rcu_lockdep_assert()                                        \
+do {                                                                    \
+        RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&                       \
+                                !lockdep_is_held(&dev_opp_list_lock),   \
+                           "Missing rcu_read_lock() or "                \
+                           "dev_opp_list_lock protection");             \
+} while (0)
+
+static struct device_list_opp *_find_list_dev(const struct device *dev,
+                                              struct device_opp *dev_opp)
+{
+        struct device_list_opp *list_dev;
+
+        list_for_each_entry(list_dev, &dev_opp->dev_list, node)
+                if (list_dev->dev == dev)
+                        return list_dev;
+
+        return NULL;
+}
+
+static struct device_opp *_managed_opp(const struct device_node *np)
+{
+        struct device_opp *dev_opp;
+
+        list_for_each_entry_rcu(dev_opp, &dev_opp_list, node) {
+                if (dev_opp->np == np) {
+                        /*
+                         * Multiple devices can point to the same OPP table and
+                         * so will have same node-pointer, np.
+                         *
+                         * But the OPPs will be considered as shared only if the
+                         * OPP table contains a "opp-shared" property.
+                         */
+                        return dev_opp->shared_opp ? dev_opp : NULL;
+                }
+        }
+
+        return NULL;
+}
+
+/**
+ * _find_device_opp() - find device_opp struct using device pointer
+ * @dev:        device pointer used to lookup device OPPs
+ *
+ * Search list of device OPPs for one containing matching device. Does a RCU
+ * reader operation to grab the pointer needed.
+ *
+ * Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
+ * -EINVAL based on type of error.
+ *
+ * Locking: This function must be called under rcu_read_lock(). device_opp
+ * is a RCU protected pointer. This means that device_opp is valid as long
+ * as we are under RCU lock.
+ */
+struct device_opp *_find_device_opp(struct device *dev)
+{
+        struct device_opp *dev_opp;
+
+        if (IS_ERR_OR_NULL(dev)) {
+                pr_err("%s: Invalid parameters\n", __func__);
+                return ERR_PTR(-EINVAL);
+        }
+
+        list_for_each_entry_rcu(dev_opp, &dev_opp_list, node)
+                if (_find_list_dev(dev, dev_opp))
+                        return dev_opp;
+
+        return ERR_PTR(-ENODEV);
+}
+
+/**
+ * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
+ * @opp:        opp for which voltage has to be returned for
+ *
+ * Return: voltage in micro volt corresponding to the opp, else
+ * return 0
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. This means that opp which could have been fetched by
+ * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
+ * under RCU lock. The pointer returned by the opp_find_freq family must be
+ * used in the same section as the usage of this function with the pointer
+ * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
+ * pointer.
+ */
+unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
+{
+        struct dev_pm_opp *tmp_opp;
+        unsigned long v = 0;
+
+        opp_rcu_lockdep_assert();
+
+        tmp_opp = rcu_dereference(opp);
+        if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
+                pr_err("%s: Invalid parameters\n", __func__);
+        else
+                v = tmp_opp->u_volt;
+
+        return v;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
+
+/**
+ * dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
+ * @opp:        opp for which frequency has to be returned for
+ *
+ * Return: frequency in hertz corresponding to the opp, else
+ * return 0
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. This means that opp which could have been fetched by
+ * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
+ * under RCU lock. The pointer returned by the opp_find_freq family must be
+ * used in the same section as the usage of this function with the pointer
+ * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
+ * pointer.
+ */
+unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
+{
+        struct dev_pm_opp *tmp_opp;
+        unsigned long f = 0;
+
+        opp_rcu_lockdep_assert();
+
+        tmp_opp = rcu_dereference(opp);
+        if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
+                pr_err("%s: Invalid parameters\n", __func__);
+        else
+                f = tmp_opp->rate;
+
+        return f;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
+
+/**
+ * dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
+ * @opp: opp for which turbo mode is being verified
+ *
+ * Turbo OPPs are not for normal use, and can be enabled (under certain
+ * conditions) for short duration of times to finish high throughput work
+ * quickly. Running on them for longer times may overheat the chip.
+ *
+ * Return: true if opp is turbo opp, else false.
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. This means that opp which could have been fetched by
+ * opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
+ * under RCU lock. The pointer returned by the opp_find_freq family must be
+ * used in the same section as the usage of this function with the pointer
+ * prior to unlocking with rcu_read_unlock() to maintain the integrity of the
+ * pointer.
+ */
+bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
+{
+        struct dev_pm_opp *tmp_opp;
+
+        opp_rcu_lockdep_assert();
+
+        tmp_opp = rcu_dereference(opp);
+        if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
+                pr_err("%s: Invalid parameters\n", __func__);
+                return false;
+        }
+
+        return tmp_opp->turbo;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
+
+/**
+ * dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
+ * @dev:        device for which we do this operation
+ *
+ * Return: This function returns the max clock latency in nanoseconds.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
+{
+        struct device_opp *dev_opp;
+        unsigned long clock_latency_ns;
+
+        rcu_read_lock();
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp))
+                clock_latency_ns = 0;
+        else
+                clock_latency_ns = dev_opp->clock_latency_ns_max;
+
+        rcu_read_unlock();
+        return clock_latency_ns;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
+
+/**
+ * dev_pm_opp_get_suspend_opp() - Get suspend opp
+ * @dev:        device for which we do this operation
+ *
+ * Return: This function returns pointer to the suspend opp if it is
+ * defined and available, otherwise it returns NULL.
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
+ */
+struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
+{
+        struct device_opp *dev_opp;
+
+        opp_rcu_lockdep_assert();
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp) || !dev_opp->suspend_opp ||
+            !dev_opp->suspend_opp->available)
+                return NULL;
+
+        return dev_opp->suspend_opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp);
+
+/**
+ * dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
+ * @dev:        device for which we do this operation
+ *
+ * Return: This function returns the number of available opps if there are any,
+ * else returns 0 if none or the corresponding error value.
+ *
+ * Locking: This function takes rcu_read_lock().
+ */
+int dev_pm_opp_get_opp_count(struct device *dev)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *temp_opp;
+        int count = 0;
+
+        rcu_read_lock();
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp)) {
+                count = PTR_ERR(dev_opp);
+                dev_err(dev, "%s: device OPP not found (%d)\n",
+                        __func__, count);
+                goto out_unlock;
+        }
+
+        list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
+                if (temp_opp->available)
+                        count++;
+        }
+
+out_unlock:
+        rcu_read_unlock();
+        return count;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
+
+/**
+ * dev_pm_opp_find_freq_exact() - search for an exact frequency
+ * @dev:                device for which we do this operation
+ * @freq:               frequency to search for
+ * @available:          true/false - match for available opp
+ *
+ * Return: Searches for exact match in the opp list and returns pointer to the
+ * matching opp if found, else returns ERR_PTR in case of error and should
+ * be handled using IS_ERR. Error return values can be:
+ * EINVAL:      for bad pointer
+ * ERANGE:      no match found for search
+ * ENODEV:      if device not found in list of registered devices
+ *
+ * Note: available is a modifier for the search. if available=true, then the
+ * match is for exact matching frequency and is available in the stored OPP
+ * table. if false, the match is for exact frequency which is not available.
+ *
+ * This provides a mechanism to enable an opp which is not available currently
+ * or the opposite as well.
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
+ */
+struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
+                                              unsigned long freq,
+                                              bool available)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+        opp_rcu_lockdep_assert();
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp)) {
+                int r = PTR_ERR(dev_opp);
+                dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
+                return ERR_PTR(r);
+        }
+
+        list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
+                if (temp_opp->available == available &&
+                                temp_opp->rate == freq) {
+                        opp = temp_opp;
+                        break;
+                }
+        }
+
+        return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
+
+/**
+ * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
+ * @dev:        device for which we do this operation
+ * @freq:       Start frequency
+ *
+ * Search for the matching ceil *available* OPP from a starting freq
+ * for a device.
+ *
+ * Return: matching *opp and refreshes *freq accordingly, else returns
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:      for bad pointer
+ * ERANGE:      no match found for search
+ * ENODEV:      if device not found in list of registered devices
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
+ */
+struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
+                                             unsigned long *freq)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+        opp_rcu_lockdep_assert();
+
+        if (!dev || !freq) {
+                dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
+                return ERR_PTR(-EINVAL);
+        }
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp))
+                return ERR_CAST(dev_opp);
+
+        list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
+                if (temp_opp->available && temp_opp->rate >= *freq) {
+                        opp = temp_opp;
+                        *freq = opp->rate;
+                        break;
+                }
+        }
+
+        return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
+
+/**
+ * dev_pm_opp_find_freq_floor() - Search for a rounded floor freq
+ * @dev:        device for which we do this operation
+ * @freq:       Start frequency
+ *
+ * Search for the matching floor *available* OPP from a starting freq
+ * for a device.
+ *
+ * Return: matching *opp and refreshes *freq accordingly, else returns
+ * ERR_PTR in case of error and should be handled using IS_ERR. Error return
+ * values can be:
+ * EINVAL:      for bad pointer
+ * ERANGE:      no match found for search
+ * ENODEV:      if device not found in list of registered devices
+ *
+ * Locking: This function must be called under rcu_read_lock(). opp is a rcu
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
+ */
+struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
+                                              unsigned long *freq)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+        opp_rcu_lockdep_assert();
+
+        if (!dev || !freq) {
+                dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
+                return ERR_PTR(-EINVAL);
+        }
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp))
+                return ERR_CAST(dev_opp);
+
+        list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
+                if (temp_opp->available) {
+                        /* go to the next node, before choosing prev */
+                        if (temp_opp->rate > *freq)
+                                break;
+                        else
+                                opp = temp_opp;
+                }
+        }
+        if (!IS_ERR(opp))
+                *freq = opp->rate;
+
+        return opp;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
+
+/* List-dev Helpers */
+static void _kfree_list_dev_rcu(struct rcu_head *head)
+{
+        struct device_list_opp *list_dev;
+
+        list_dev = container_of(head, struct device_list_opp, rcu_head);
+        kfree_rcu(list_dev, rcu_head);
+}
+
+static void _remove_list_dev(struct device_list_opp *list_dev,
+                             struct device_opp *dev_opp)
+{
+        list_del(&list_dev->node);
+        call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
+                  _kfree_list_dev_rcu);
+}
+
+struct device_list_opp *_add_list_dev(const struct device *dev,
+                                      struct device_opp *dev_opp)
+{
+        struct device_list_opp *list_dev;
+
+        list_dev = kzalloc(sizeof(*list_dev), GFP_KERNEL);
+        if (!list_dev)
+                return NULL;
+
+        /* Initialize list-dev */
+        list_dev->dev = dev;
+        list_add_rcu(&list_dev->node, &dev_opp->dev_list);
+
+        return list_dev;
+}
+
+/**
+ * _add_device_opp() - Find device OPP table or allocate a new one
+ * @dev:        device for which we do this operation
+ *
+ * It tries to find an existing table first, if it couldn't find one, it
+ * allocates a new OPP table and returns that.
+ *
+ * Return: valid device_opp pointer if success, else NULL.
+ */
+static struct device_opp *_add_device_opp(struct device *dev)
+{
+        struct device_opp *dev_opp;
+        struct device_list_opp *list_dev;
+
+        /* Check for existing list for 'dev' first */
+        dev_opp = _find_device_opp(dev);
+        if (!IS_ERR(dev_opp))
+                return dev_opp;
+
+        /*
+         * Allocate a new device OPP table. In the infrequent case where a new
+         * device is needed to be added, we pay this penalty.
+         */
+        dev_opp = kzalloc(sizeof(*dev_opp), GFP_KERNEL);
+        if (!dev_opp)
+                return NULL;
+
+        INIT_LIST_HEAD(&dev_opp->dev_list);
+
+        list_dev = _add_list_dev(dev, dev_opp);
+        if (!list_dev) {
+                kfree(dev_opp);
+                return NULL;
+        }
+
+        srcu_init_notifier_head(&dev_opp->srcu_head);
+        INIT_LIST_HEAD(&dev_opp->opp_list);
+
+        /* Secure the device list modification */
+        list_add_rcu(&dev_opp->node, &dev_opp_list);
+        return dev_opp;
+}
+
+/**
+ * _kfree_device_rcu() - Free device_opp RCU handler
+ * @head:       RCU head
+ */
+static void _kfree_device_rcu(struct rcu_head *head)
+{
+        struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
+
+        kfree_rcu(device_opp, rcu_head);
+}
+
+/**
+ * _remove_device_opp() - Removes a device OPP table
+ * @dev_opp: device OPP table to be removed.
+ *
+ * Removes/frees device OPP table it it doesn't contain any OPPs.
+ */
+static void _remove_device_opp(struct device_opp *dev_opp)
+{
+        struct device_list_opp *list_dev;
+
+        if (!list_empty(&dev_opp->opp_list))
+                return;
+
+        list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,
+                                    node);
+
+        _remove_list_dev(list_dev, dev_opp);
+
+        /* dev_list must be empty now */
+        WARN_ON(!list_empty(&dev_opp->dev_list));
+
+        list_del_rcu(&dev_opp->node);
+        call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
+                  _kfree_device_rcu);
+}
+
+/**
+ * _kfree_opp_rcu() - Free OPP RCU handler
+ * @head:       RCU head
+ */
+static void _kfree_opp_rcu(struct rcu_head *head)
+{
+        struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
+
+        kfree_rcu(opp, rcu_head);
+}
+
+/**
+ * _opp_remove()  - Remove an OPP from a table definition
+ * @dev_opp:    points back to the device_opp struct this opp belongs to
+ * @opp:        pointer to the OPP to remove
+ * @notify:     OPP_EVENT_REMOVE notification should be sent or not
+ *
+ * This function removes an opp definition from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * It is assumed that the caller holds required mutex for an RCU updater
+ * strategy.
+ */
+static void _opp_remove(struct device_opp *dev_opp,
+                        struct dev_pm_opp *opp, bool notify)
+{
+        /*
+         * Notify the changes in the availability of the operable
+         * frequency/voltage list.
+         */
+        if (notify)
+                srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
+        list_del_rcu(&opp->node);
+        call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
+
+        _remove_device_opp(dev_opp);
+}
+
+/**
+ * dev_pm_opp_remove()  - Remove an OPP from OPP list
+ * @dev:        device for which we do this operation
+ * @freq:       OPP to remove with matching 'freq'
+ *
+ * This function removes an opp from the opp list.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ */
+void dev_pm_opp_remove(struct device *dev, unsigned long freq)
+{
+        struct dev_pm_opp *opp;
+        struct device_opp *dev_opp;
+        bool found = false;
+
+        /* Hold our list modification lock here */
+        mutex_lock(&dev_opp_list_lock);
+
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp))
+                goto unlock;
+
+        list_for_each_entry(opp, &dev_opp->opp_list, node) {
+                if (opp->rate == freq) {
+                        found = true;
+                        break;
+                }
+        }
+
+        if (!found) {
+                dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
+                         __func__, freq);
+                goto unlock;
+        }
+
+        _opp_remove(dev_opp, opp, true);
+unlock:
+        mutex_unlock(&dev_opp_list_lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
+
+static struct dev_pm_opp *_allocate_opp(struct device *dev,
+                                        struct device_opp **dev_opp)
+{
+        struct dev_pm_opp *opp;
+
+        /* allocate new OPP node */
+        opp = kzalloc(sizeof(*opp), GFP_KERNEL);
+        if (!opp)
+                return NULL;
+
+        INIT_LIST_HEAD(&opp->node);
+
+        *dev_opp = _add_device_opp(dev);
+        if (!*dev_opp) {
+                kfree(opp);
+                return NULL;
+        }
+
+        return opp;
+}
+
+static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
+                    struct device_opp *dev_opp)
+{
+        struct dev_pm_opp *opp;
+        struct list_head *head = &dev_opp->opp_list;
+
+        /*
+         * Insert new OPP in order of increasing frequency and discard if
+         * already present.
+         *
+         * Need to use &dev_opp->opp_list in the condition part of the 'for'
+         * loop, don't replace it with head otherwise it will become an infinite
+         * loop.
+         */
+        list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
+                if (new_opp->rate > opp->rate) {
+                        head = &opp->node;
+                        continue;
+                }
+
+                if (new_opp->rate < opp->rate)
+                        break;
+
+                /* Duplicate OPPs */
+                dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
+                         __func__, opp->rate, opp->u_volt, opp->available,
+                         new_opp->rate, new_opp->u_volt, new_opp->available);
+
+                return opp->available && new_opp->u_volt == opp->u_volt ?
+                        0 : -EEXIST;
+        }
+
+        new_opp->dev_opp = dev_opp;
+        list_add_rcu(&new_opp->node, head);
+
+        return 0;
+}
+
+/**
+ * _opp_add_dynamic() - Allocate a dynamic OPP.
+ * @dev:        device for which we do this operation
+ * @freq:       Frequency in Hz for this OPP
+ * @u_volt:     Voltage in uVolts for this OPP
+ * @dynamic:    Dynamically added OPPs.
+ *
+ * This function adds an opp definition to the opp list and returns status.
+ * The opp is made available by default and it can be controlled using
+ * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
+ *
+ * NOTE: "dynamic" parameter impacts OPPs added by the dev_pm_opp_of_add_table
+ * and freed by dev_pm_opp_of_remove_table.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0            On success OR
+ *              Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST      Freq are same and volt are different OR
+ *              Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM      Memory allocation failure
+ */
+static int _opp_add_dynamic(struct device *dev, unsigned long freq,
+                            long u_volt, bool dynamic)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *new_opp;
+        int ret;
+
+        /* Hold our list modification lock here */
+        mutex_lock(&dev_opp_list_lock);
+
+        new_opp = _allocate_opp(dev, &dev_opp);
+        if (!new_opp) {
+                ret = -ENOMEM;
+                goto unlock;
+        }
+
+        /* populate the opp table */
+        new_opp->rate = freq;
+        new_opp->u_volt = u_volt;
+        new_opp->available = true;
+        new_opp->dynamic = dynamic;
+
+        ret = _opp_add(dev, new_opp, dev_opp);
+        if (ret)
+                goto free_opp;
+
+        mutex_unlock(&dev_opp_list_lock);
+
+        /*
+         * Notify the changes in the availability of the operable
+         * frequency/voltage list.
+         */
+        srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
+        return 0;
+
+free_opp:
+        _opp_remove(dev_opp, new_opp, false);
+unlock:
+        mutex_unlock(&dev_opp_list_lock);
+        return ret;
+}
+
+/* TODO: Support multiple regulators */
+static int opp_get_microvolt(struct dev_pm_opp *opp, struct device *dev)
+{
+        u32 microvolt[3] = {0};
+        int count, ret;
+
+        /* Missing property isn't a problem, but an invalid entry is */
+        if (!of_find_property(opp->np, "opp-microvolt", NULL))
+                return 0;
+
+        count = of_property_count_u32_elems(opp->np, "opp-microvolt");
+        if (count < 0) {
+                dev_err(dev, "%s: Invalid opp-microvolt property (%d)\n",
+                        __func__, count);
+                return count;
+        }
+
+        /* There can be one or three elements here */
+        if (count != 1 && count != 3) {
+                dev_err(dev, "%s: Invalid number of elements in opp-microvolt property (%d)\n",
+                        __func__, count);
+                return -EINVAL;
+        }
+
+        ret = of_property_read_u32_array(opp->np, "opp-microvolt", microvolt,
+                                         count);
+        if (ret) {
+                dev_err(dev, "%s: error parsing opp-microvolt: %d\n", __func__,
+                        ret);
+                return -EINVAL;
+        }
+
+        opp->u_volt = microvolt[0];
+        opp->u_volt_min = microvolt[1];
+        opp->u_volt_max = microvolt[2];
+
+        return 0;
+}
+
+/**
+ * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
+ * @dev:        device for which we do this operation
+ * @np:         device node
+ *
+ * This function adds an opp definition to the opp list and returns status. The
+ * opp can be controlled using dev_pm_opp_enable/disable functions and may be
+ * removed by dev_pm_opp_remove.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0            On success OR
+ *              Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST      Freq are same and volt are different OR
+ *              Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM      Memory allocation failure
+ * -EINVAL      Failed parsing the OPP node
+ */
+static int _opp_add_static_v2(struct device *dev, struct device_node *np)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *new_opp;
+        u64 rate;
+        u32 val;
+        int ret;
+
+        /* Hold our list modification lock here */
+        mutex_lock(&dev_opp_list_lock);
+
+        new_opp = _allocate_opp(dev, &dev_opp);
+        if (!new_opp) {
+                ret = -ENOMEM;
+                goto unlock;
+        }
+
+        ret = of_property_read_u64(np, "opp-hz", &rate);
+        if (ret < 0) {
+                dev_err(dev, "%s: opp-hz not found\n", __func__);
+                goto free_opp;
+        }
+
+        /*
+         * Rate is defined as an unsigned long in clk API, and so casting
+         * explicitly to its type. Must be fixed once rate is 64 bit
+         * guaranteed in clk API.
+         */
+        new_opp->rate = (unsigned long)rate;
+        new_opp->turbo = of_property_read_bool(np, "turbo-mode");
+
+        new_opp->np = np;
+        new_opp->dynamic = false;
+        new_opp->available = true;
+
+        if (!of_property_read_u32(np, "clock-latency-ns", &val))
+                new_opp->clock_latency_ns = val;
+
+        ret = opp_get_microvolt(new_opp, dev);
+        if (ret)
+                goto free_opp;
+
+        if (!of_property_read_u32(new_opp->np, "opp-microamp", &val))
+                new_opp->u_amp = val;
+
+        ret = _opp_add(dev, new_opp, dev_opp);
+        if (ret)
+                goto free_opp;
+
+        /* OPP to select on device suspend */
+        if (of_property_read_bool(np, "opp-suspend")) {
+                if (dev_opp->suspend_opp)
+                        dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
+                                 __func__, dev_opp->suspend_opp->rate,
+                                 new_opp->rate);
+                else
+                        dev_opp->suspend_opp = new_opp;
+        }
+
+        if (new_opp->clock_latency_ns > dev_opp->clock_latency_ns_max)
+                dev_opp->clock_latency_ns_max = new_opp->clock_latency_ns;
+
+        mutex_unlock(&dev_opp_list_lock);
+
+        pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
+                 __func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
+                 new_opp->u_volt_min, new_opp->u_volt_max,
+                 new_opp->clock_latency_ns);
+
+        /*
+         * Notify the changes in the availability of the operable
+         * frequency/voltage list.
+         */
+        srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
+        return 0;
+
+free_opp:
+        _opp_remove(dev_opp, new_opp, false);
+unlock:
+        mutex_unlock(&dev_opp_list_lock);
+        return ret;
+}
+
+/**
+ * dev_pm_opp_add()  - Add an OPP table from a table definitions
+ * @dev:        device for which we do this operation
+ * @freq:       Frequency in Hz for this OPP
+ * @u_volt:     Voltage in uVolts for this OPP
+ *
+ * This function adds an opp definition to the opp list and returns status.
+ * The opp is made available by default and it can be controlled using
+ * dev_pm_opp_enable/disable functions.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0            On success OR
+ *              Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST      Freq are same and volt are different OR
+ *              Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM      Memory allocation failure
+ */
+int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
+{
+        return _opp_add_dynamic(dev, freq, u_volt, true);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_add);
+
+/**
+ * _opp_set_availability() - helper to set the availability of an opp
+ * @dev:                device for which we do this operation
+ * @freq:               OPP frequency to modify availability
+ * @availability_req:   availability status requested for this opp
+ *
+ * Set the availability of an OPP with an RCU operation, opp_{enable,disable}
+ * share a common logic which is isolated here.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modification was done OR modification was
+ * successful.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks to
+ * keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ */
+static int _opp_set_availability(struct device *dev, unsigned long freq,
+                                 bool availability_req)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
+        int r = 0;
+
+        /* keep the node allocated */
+        new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
+        if (!new_opp)
+                return -ENOMEM;
+
+        mutex_lock(&dev_opp_list_lock);
+
+        /* Find the device_opp */
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp)) {
+                r = PTR_ERR(dev_opp);
+                dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
+                goto unlock;
+        }
+
+        /* Do we have the frequency? */
+        list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) {
+                if (tmp_opp->rate == freq) {
+                        opp = tmp_opp;
+                        break;
+                }
+        }
+        if (IS_ERR(opp)) {
+                r = PTR_ERR(opp);
+                goto unlock;
+        }
+
+        /* Is update really needed? */
+        if (opp->available == availability_req)
+                goto unlock;
+        /* copy the old data over */
+        *new_opp = *opp;
+
+        /* plug in new node */
+        new_opp->available = availability_req;
+
+        list_replace_rcu(&opp->node, &new_opp->node);
+        mutex_unlock(&dev_opp_list_lock);
+        call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
+
+        /* Notify the change of the OPP availability */
+        if (availability_req)
+                srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ENABLE,
+                                         new_opp);
+        else
+                srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_DISABLE,
+                                         new_opp);
+
+        return 0;
+
+unlock:
+        mutex_unlock(&dev_opp_list_lock);
+        kfree(new_opp);
+        return r;
+}
+
+/**
+ * dev_pm_opp_enable() - Enable a specific OPP
+ * @dev:        device for which we do this operation
+ * @freq:       OPP frequency to enable
+ *
+ * Enables a provided opp. If the operation is valid, this returns 0, else the
+ * corresponding error value. It is meant to be used for users an OPP available
+ * after being temporarily made unavailable with dev_pm_opp_disable.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU and mutex locks to keep the
+ * integrity of the internal data structures. Callers should ensure that
+ * this function is *NOT* called under RCU protection or in contexts where
+ * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modification was done OR modification was
+ * successful.
+ */
+int dev_pm_opp_enable(struct device *dev, unsigned long freq)
+{
+        return _opp_set_availability(dev, freq, true);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
+
+/**
+ * dev_pm_opp_disable() - Disable a specific OPP
+ * @dev:        device for which we do this operation
+ * @freq:       OPP frequency to disable
+ *
+ * Disables a provided opp. If the operation is valid, this returns
+ * 0, else the corresponding error value. It is meant to be a temporary
+ * control by users to make this OPP not available until the circumstances are
+ * right to make it available again (with a call to dev_pm_opp_enable).
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU and mutex locks to keep the
+ * integrity of the internal data structures. Callers should ensure that
+ * this function is *NOT* called under RCU protection or in contexts where
+ * mutex locking or synchronize_rcu() blocking calls cannot be used.
+ *
+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
+ * copy operation, returns 0 if no modification was done OR modification was
+ * successful.
+ */
+int dev_pm_opp_disable(struct device *dev, unsigned long freq)
+{
+        return _opp_set_availability(dev, freq, false);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
+
+/**
+ * dev_pm_opp_get_notifier() - find notifier_head of the device with opp
+ * @dev:        device pointer used to lookup device OPPs.
+ *
+ * Return: pointer to  notifier head if found, otherwise -ENODEV or
+ * -EINVAL based on type of error casted as pointer. value must be checked
+ *  with IS_ERR to determine valid pointer or error result.
+ *
+ * Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
+ * protected pointer. The reason for the same is that the opp pointer which is
+ * returned will remain valid for use with opp_get_{voltage, freq} only while
+ * under the locked area. The pointer returned must be used prior to unlocking
+ * with rcu_read_unlock() to maintain the integrity of the pointer.
+ */
+struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
+{
+        struct device_opp *dev_opp = _find_device_opp(dev);
+
+        if (IS_ERR(dev_opp))
+                return ERR_CAST(dev_opp); /* matching type */
+
+        return &dev_opp->srcu_head;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
+
+#ifdef CONFIG_OF
+/**
+ * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
+ *                                entries
+ * @dev:        device pointer used to lookup device OPPs.
+ *
+ * Free OPPs created using static entries present in DT.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ */
+void dev_pm_opp_of_remove_table(struct device *dev)
+{
+        struct device_opp *dev_opp;
+        struct dev_pm_opp *opp, *tmp;
+
+        /* Hold our list modification lock here */
+        mutex_lock(&dev_opp_list_lock);
+
+        /* Check for existing list for 'dev' */
+        dev_opp = _find_device_opp(dev);
+        if (IS_ERR(dev_opp)) {
+                int error = PTR_ERR(dev_opp);
+
+                if (error != -ENODEV)
+                        WARN(1, "%s: dev_opp: %d\n",
+                             IS_ERR_OR_NULL(dev) ?
+                                        "Invalid device" : dev_name(dev),
+                             error);
+                goto unlock;
+        }
+
+        /* Find if dev_opp manages a single device */
+        if (list_is_singular(&dev_opp->dev_list)) {
+                /* Free static OPPs */
+                list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
+                        if (!opp->dynamic)
+                                _opp_remove(dev_opp, opp, true);
+                }
+        } else {
+                _remove_list_dev(_find_list_dev(dev, dev_opp), dev_opp);
+        }
+
+unlock:
+        mutex_unlock(&dev_opp_list_lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
+
+/* Returns opp descriptor node for a device, caller must do of_node_put() */
+struct device_node *_of_get_opp_desc_node(struct device *dev)
+{
+        /*
+         * TODO: Support for multiple OPP tables.
+         *
+         * There should be only ONE phandle present in "operating-points-v2"
+         * property.
+         */
+
+        return of_parse_phandle(dev->of_node, "operating-points-v2", 0);
+}
+
+/* Initializes OPP tables based on new bindings */
+static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
+{
+        struct device_node *np;
+        struct device_opp *dev_opp;
+        int ret = 0, count = 0;
+
+        dev_opp = _managed_opp(opp_np);
+        if (dev_opp) {
+                /* OPPs are already managed */
+                if (!_add_list_dev(dev, dev_opp))
+                        ret = -ENOMEM;
+                return ret;
+        }
+
+        /* We have opp-list node now, iterate over it and add OPPs */
+        for_each_available_child_of_node(opp_np, np) {
+                count++;
+
+                ret = _opp_add_static_v2(dev, np);
+                if (ret) {
+                        dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
+                                ret);
+                        goto free_table;
+                }
+        }
+
+        /* There should be one of more OPP defined */
+        if (WARN_ON(!count))
+                return -ENOENT;
+
+        dev_opp = _find_device_opp(dev);
+        if (WARN_ON(IS_ERR(dev_opp))) {
+                ret = PTR_ERR(dev_opp);
+                goto free_table;
+        }
+
+        dev_opp->np = opp_np;
+        dev_opp->shared_opp = of_property_read_bool(opp_np, "opp-shared");
+
+        return 0;
+
+free_table:
+        dev_pm_opp_of_remove_table(dev);
+
+        return ret;
+}
+
+/* Initializes OPP tables based on old-deprecated bindings */
+static int _of_add_opp_table_v1(struct device *dev)
+{
+        const struct property *prop;
+        const __be32 *val;
+        int nr;
+
+        prop = of_find_property(dev->of_node, "operating-points", NULL);
+        if (!prop)
+                return -ENODEV;
+        if (!prop->value)
+                return -ENODATA;
+
+        /*
+         * Each OPP is a set of tuples consisting of frequency and
+         * voltage like <freq-kHz vol-uV>.
+         */
+        nr = prop->length / sizeof(u32);
+        if (nr % 2) {
+                dev_err(dev, "%s: Invalid OPP list\n", __func__);
+                return -EINVAL;
+        }
+
+        val = prop->value;
+        while (nr) {
+                unsigned long freq = be32_to_cpup(val++) * 1000;
+                unsigned long volt = be32_to_cpup(val++);
+
+                if (_opp_add_dynamic(dev, freq, volt, false))
+                        dev_warn(dev, "%s: Failed to add OPP %ld\n",
+                                 __func__, freq);
+                nr -= 2;
+        }
+
+        return 0;
+}
+
+/**
+ * dev_pm_opp_of_add_table() - Initialize opp table from device tree
+ * @dev:        device pointer used to lookup device OPPs.
+ *
+ * Register the initial OPP table with the OPP library for given device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0            On success OR
+ *              Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST      Freq are same and volt are different OR
+ *              Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM      Memory allocation failure
+ * -ENODEV      when 'operating-points' property is not found or is invalid data
+ *              in device node.
+ * -ENODATA     when empty 'operating-points' property is found
+ * -EINVAL      when invalid entries are found in opp-v2 table
+ */
+int dev_pm_opp_of_add_table(struct device *dev)
+{
+        struct device_node *opp_np;
+        int ret;
+
+        /*
+         * OPPs have two version of bindings now. The older one is deprecated,
+         * try for the new binding first.
+         */
+        opp_np = _of_get_opp_desc_node(dev);
+        if (!opp_np) {
+                /*
+                 * Try old-deprecated bindings for backward compatibility with
+                 * older dtbs.
+                 */
+                return _of_add_opp_table_v1(dev);
+        }
+
+        ret = _of_add_opp_table_v2(dev, opp_np);
+        of_node_put(opp_np);
+
+        return ret;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
+#endif