Merge branch 'pm-opp'

* pm-opp: (24 commits)
  PM / OPP: Expose _of_get_opp_desc_node as dev_pm_opp API
  PM / OPP: Make _find_opp_table_unlocked() static
  PM / OPP: Update Documentation to remove RCU specific bits
  PM / OPP: Simplify dev_pm_opp_get_max_volt_latency()
  PM / OPP: Simplify _opp_set_availability()
  PM / OPP: Move away from RCU locking
  PM / OPP: Take kref from _find_opp_table()
  PM / OPP: Update OPP users to put reference
  PM / OPP: Add 'struct kref' to struct dev_pm_opp
  PM / OPP: Use dev_pm_opp_get_opp_table() instead of _add_opp_table()
  PM / OPP: Take reference of the OPP table while adding/removing OPPs
  PM / OPP: Return opp_table from dev_pm_opp_set_*() routines
  PM / OPP: Add 'struct kref' to OPP table
  PM / OPP: Add per OPP table mutex
  PM / OPP: Split out part of _add_opp_table() and _remove_opp_table()
  PM / OPP: Don't expose srcu_head to register notifiers
  PM / OPP: Rename dev_pm_opp_get_suspend_opp() and return OPP rate
  PM / OPP: Don't allocate OPP table from _opp_allocate()
  PM / OPP: Rename and split _dev_pm_opp_remove_table()
  PM / OPP: Add light weight _opp_free() routine
  ...

4 files changed, 476 insertions, 795 deletions

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 35ff06283738..91ec3232d630 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -32,13 +32,7 @@ LIST_HEAD(opp_tables);
 /* Lock to allow exclusive modification to the device and opp lists */
 DEFINE_MUTEX(opp_table_lock);
 
-#define opp_rcu_lockdep_assert()                                        \
-do {                                                                    \
-        RCU_LOCKDEP_WARN(!rcu_read_lock_held() &&                       \
-                         !lockdep_is_held(&opp_table_lock),             \
-                         "Missing rcu_read_lock() or "                  \
-                         "opp_table_lock protection");                  \
-} while (0)
+static void dev_pm_opp_get(struct dev_pm_opp *opp);
 
 static struct opp_device *_find_opp_dev(const struct device *dev,
                                         struct opp_table *opp_table)
@@ -52,38 +46,46 @@ static struct opp_device *_find_opp_dev(const struct device *dev,
         return NULL;
 }
 
+static struct opp_table *_find_opp_table_unlocked(struct device *dev)
+{
+        struct opp_table *opp_table;
+
+        list_for_each_entry(opp_table, &opp_tables, node) {
+                if (_find_opp_dev(dev, opp_table)) {
+                        _get_opp_table_kref(opp_table);
+
+                        return opp_table;
+                }
+        }
+
+        return ERR_PTR(-ENODEV);
+}
+
 /**
  * _find_opp_table() - find opp_table struct using device pointer
  * @dev:        device pointer used to lookup OPP table
  *
- * Search OPP table for one containing matching device. Does a RCU reader
- * operation to grab the pointer needed.
+ * Search OPP table for one containing matching device.
  *
  * Return: pointer to 'struct opp_table' if found, otherwise -ENODEV or
  * -EINVAL based on type of error.
  *
- * Locking: For readers, this function must be called under rcu_read_lock().
- * opp_table is a RCU protected pointer, which means that opp_table is valid
- * as long as we are under RCU lock.
- *
- * For Writers, this function must be called with opp_table_lock held.
+ * The callers must call dev_pm_opp_put_opp_table() after the table is used.
  */
 struct opp_table *_find_opp_table(struct device *dev)
 {
         struct opp_table *opp_table;
 
-        opp_rcu_lockdep_assert();
-
         if (IS_ERR_OR_NULL(dev)) {
                 pr_err("%s: Invalid parameters\n", __func__);
                 return ERR_PTR(-EINVAL);
         }
 
-        list_for_each_entry_rcu(opp_table, &opp_tables, node)
-                if (_find_opp_dev(dev, opp_table))
-                        return opp_table;
+        mutex_lock(&opp_table_lock);
+        opp_table = _find_opp_table_unlocked(dev);
+        mutex_unlock(&opp_table_lock);
 
-        return ERR_PTR(-ENODEV);
+        return opp_table;
 }
 
 /**
@@ -94,29 +96,15 @@ struct opp_table *_find_opp_table(struct device *dev)
  * return 0
  *
  * This is useful only for devices with single power supply.
- *
- * 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))
+        if (IS_ERR_OR_NULL(opp)) {
                 pr_err("%s: Invalid parameters\n", __func__);
-        else
-                v = tmp_opp->supplies[0].u_volt;
+                return 0;
+        }
 
-        return v;
+        return opp->supplies[0].u_volt;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
 
@@ -126,29 +114,15 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
  *
  * 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)
+        if (IS_ERR_OR_NULL(opp) || !opp->available) {
                 pr_err("%s: Invalid parameters\n", __func__);
-        else
-                f = tmp_opp->rate;
+                return 0;
+        }
 
-        return f;
+        return opp->rate;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
 
@@ -161,28 +135,15 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
  * 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) {
+        if (IS_ERR_OR_NULL(opp) || !opp->available) {
                 pr_err("%s: Invalid parameters\n", __func__);
                 return false;
         }
 
-        return tmp_opp->turbo;
+        return opp->turbo;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
 
@@ -191,52 +152,29 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
  * @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 opp_table *opp_table;
         unsigned long clock_latency_ns;
 
-        rcu_read_lock();
-
         opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table))
-                clock_latency_ns = 0;
-        else
-                clock_latency_ns = opp_table->clock_latency_ns_max;
-
-        rcu_read_unlock();
-        return clock_latency_ns;
-}
-EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
-
-static int _get_regulator_count(struct device *dev)
-{
-        struct opp_table *opp_table;
-        int count;
+                return 0;
 
-        rcu_read_lock();
+        clock_latency_ns = opp_table->clock_latency_ns_max;
 
-        opp_table = _find_opp_table(dev);
-        if (!IS_ERR(opp_table))
-                count = opp_table->regulator_count;
-        else
-                count = 0;
+        dev_pm_opp_put_opp_table(opp_table);
 
-        rcu_read_unlock();
-
-        return count;
+        return clock_latency_ns;
 }
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
 
 /**
  * dev_pm_opp_get_max_volt_latency() - Get max voltage latency in nanoseconds
  * @dev: device for which we do this operation
  *
  * Return: This function returns the max voltage latency in nanoseconds.
- *
- * Locking: This function takes rcu_read_lock().
  */
 unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 {
@@ -250,35 +188,33 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
                 unsigned long max;
         } *uV;
 
-        count = _get_regulator_count(dev);
+        opp_table = _find_opp_table(dev);
+        if (IS_ERR(opp_table))
+                return 0;
+
+        count = opp_table->regulator_count;
 
         /* Regulator may not be required for the device */
         if (!count)
-                return 0;
+                goto put_opp_table;
 
         regulators = kmalloc_array(count, sizeof(*regulators), GFP_KERNEL);
         if (!regulators)
-                return 0;
+                goto put_opp_table;
 
         uV = kmalloc_array(count, sizeof(*uV), GFP_KERNEL);
         if (!uV)
                 goto free_regulators;
 
-        rcu_read_lock();
-
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                rcu_read_unlock();
-                goto free_uV;
-        }
-
         memcpy(regulators, opp_table->regulators, count * sizeof(*regulators));
 
+        mutex_lock(&opp_table->lock);
+
         for (i = 0; i < count; i++) {
                 uV[i].min = ~0;
                 uV[i].max = 0;
 
-                list_for_each_entry_rcu(opp, &opp_table->opp_list, node) {
+                list_for_each_entry(opp, &opp_table->opp_list, node) {
                         if (!opp->available)
                                 continue;
 
@@ -289,7 +225,7 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
                 }
         }
 
-        rcu_read_unlock();
+        mutex_unlock(&opp_table->lock);
 
         /*
          * The caller needs to ensure that opp_table (and hence the regulator)
@@ -301,10 +237,11 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
                         latency_ns += ret * 1000;
         }
 
-free_uV:
         kfree(uV);
 free_regulators:
         kfree(regulators);
+put_opp_table:
+        dev_pm_opp_put_opp_table(opp_table);
 
         return latency_ns;
 }
@@ -317,8 +254,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_volt_latency);
  *
  * Return: This function returns the max transition latency, in nanoseconds, to
  * switch from one OPP to other.
- *
- * Locking: This function takes rcu_read_lock().
  */
 unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev)
 {
@@ -328,32 +263,29 @@ unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev)
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_transition_latency);
 
 /**
- * dev_pm_opp_get_suspend_opp() - Get suspend opp
+ * dev_pm_opp_get_suspend_opp_freq() - Get frequency of suspend opp in Hz
  * @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.
+ * Return: This function returns the frequency of the OPP marked as suspend_opp
+ * if one is available, else returns 0;
  */
-struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
+unsigned long dev_pm_opp_get_suspend_opp_freq(struct device *dev)
 {
         struct opp_table *opp_table;
-
-        opp_rcu_lockdep_assert();
+        unsigned long freq = 0;
 
         opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table) || !opp_table->suspend_opp ||
-            !opp_table->suspend_opp->available)
-                return NULL;
+        if (IS_ERR(opp_table))
+                return 0;
+
+        if (opp_table->suspend_opp && opp_table->suspend_opp->available)
+                freq = dev_pm_opp_get_freq(opp_table->suspend_opp);
 
-        return opp_table->suspend_opp;
+        dev_pm_opp_put_opp_table(opp_table);
+
+        return freq;
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp);
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_freq);
 
 /**
  * dev_pm_opp_get_opp_count() - Get number of opps available in the opp table
@@ -361,8 +293,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp);
  *
  * 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)
 {
@@ -370,23 +300,24 @@ int dev_pm_opp_get_opp_count(struct device *dev)
         struct dev_pm_opp *temp_opp;
         int count = 0;
 
-        rcu_read_lock();
-
         opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table)) {
                 count = PTR_ERR(opp_table);
                 dev_err(dev, "%s: OPP table not found (%d)\n",
                         __func__, count);
-                goto out_unlock;
+                return count;
         }
 
-        list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
+        mutex_lock(&opp_table->lock);
+
+        list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
                 if (temp_opp->available)
                         count++;
         }
 
-out_unlock:
-        rcu_read_unlock();
+        mutex_unlock(&opp_table->lock);
+        dev_pm_opp_put_opp_table(opp_table);
+
         return count;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
@@ -411,11 +342,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
  * 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.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
                                               unsigned long freq,
@@ -424,8 +352,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
         struct opp_table *opp_table;
         struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
-        opp_rcu_lockdep_assert();
-
         opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table)) {
                 int r = PTR_ERR(opp_table);
@@ -434,14 +360,22 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
                 return ERR_PTR(r);
         }
 
-        list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
+        mutex_lock(&opp_table->lock);
+
+        list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
                 if (temp_opp->available == available &&
                                 temp_opp->rate == freq) {
                         opp = temp_opp;
+
+                        /* Increment the reference count of OPP */
+                        dev_pm_opp_get(opp);
                         break;
                 }
         }
 
+        mutex_unlock(&opp_table->lock);
+        dev_pm_opp_put_opp_table(opp_table);
+
         return opp;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
@@ -451,14 +385,21 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
 {
         struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
-        list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
+        mutex_lock(&opp_table->lock);
+
+        list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
                 if (temp_opp->available && temp_opp->rate >= *freq) {
                         opp = temp_opp;
                         *freq = opp->rate;
+
+                        /* Increment the reference count of OPP */
+                        dev_pm_opp_get(opp);
                         break;
                 }
         }
 
+        mutex_unlock(&opp_table->lock);
+
         return opp;
 }
 
@@ -477,18 +418,14 @@ static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
  * 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.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
                                              unsigned long *freq)
 {
         struct opp_table *opp_table;
-
-        opp_rcu_lockdep_assert();
+        struct dev_pm_opp *opp;
 
         if (!dev || !freq) {
                 dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
@@ -499,7 +436,11 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
         if (IS_ERR(opp_table))
                 return ERR_CAST(opp_table);
 
-        return _find_freq_ceil(opp_table, freq);
+        opp = _find_freq_ceil(opp_table, freq);
+
+        dev_pm_opp_put_opp_table(opp_table);
+
+        return opp;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 
@@ -518,11 +459,8 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
  * 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.
+ * The callers are required to call dev_pm_opp_put() for the returned OPP after
+ * use.
  */
 struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
                                               unsigned long *freq)
@@ -530,8 +468,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
         struct opp_table *opp_table;
         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);
@@ -541,7 +477,9 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
         if (IS_ERR(opp_table))
                 return ERR_CAST(opp_table);
 
-        list_for_each_entry_rcu(temp_opp, &opp_table->opp_list, node) {
+        mutex_lock(&opp_table->lock);
+
+        list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
                 if (temp_opp->available) {
                         /* go to the next node, before choosing prev */
                         if (temp_opp->rate > *freq)
@@ -550,6 +488,13 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
                                 opp = temp_opp;
                 }
         }
+
+        /* Increment the reference count of OPP */
+        if (!IS_ERR(opp))
+                dev_pm_opp_get(opp);
+        mutex_unlock(&opp_table->lock);
+        dev_pm_opp_put_opp_table(opp_table);
+
         if (!IS_ERR(opp))
                 *freq = opp->rate;
 
@@ -557,34 +502,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
 
-/*
- * The caller needs to ensure that opp_table (and hence the clk) isn't freed,
- * while clk returned here is used.
- */
-static struct clk *_get_opp_clk(struct device *dev)
-{
-        struct opp_table *opp_table;
-        struct clk *clk;
-
-        rcu_read_lock();
-
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-                clk = ERR_CAST(opp_table);
-                goto unlock;
-        }
-
-        clk = opp_table->clk;
-        if (IS_ERR(clk))
-                dev_err(dev, "%s: No clock available for the device\n",
-                        __func__);
-
-unlock:
-        rcu_read_unlock();
-        return clk;
-}
-
 static int _set_opp_voltage(struct device *dev, struct regulator *reg,
                             struct dev_pm_opp_supply *supply)
 {
@@ -680,8 +597,6 @@ restore_voltage:
  *
  * This configures the power-supplies and clock source to the levels specified
  * by the OPP corresponding to the target_freq.
- *
- * Locking: This function takes rcu_read_lock().
  */
 int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 {
@@ -700,9 +615,19 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
                 return -EINVAL;
         }
 
-        clk = _get_opp_clk(dev);
-        if (IS_ERR(clk))
-                return PTR_ERR(clk);
+        opp_table = _find_opp_table(dev);
+        if (IS_ERR(opp_table)) {
+                dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+                return PTR_ERR(opp_table);
+        }
+
+        clk = opp_table->clk;
+        if (IS_ERR(clk)) {
+                dev_err(dev, "%s: No clock available for the device\n",
+                        __func__);
+                ret = PTR_ERR(clk);
+                goto put_opp_table;
+        }
 
         freq = clk_round_rate(clk, target_freq);
         if ((long)freq <= 0)
@@ -714,16 +639,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
         if (old_freq == freq) {
                 dev_dbg(dev, "%s: old/new frequencies (%lu Hz) are same, nothing to do\n",
                         __func__, freq);
-                return 0;
-        }
-
-        rcu_read_lock();
-
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-                rcu_read_unlock();
-                return PTR_ERR(opp_table);
+                ret = 0;
+                goto put_opp_table;
         }
 
         old_opp = _find_freq_ceil(opp_table, &old_freq);
@@ -737,8 +654,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
                 ret = PTR_ERR(opp);
                 dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
                         __func__, freq, ret);
-                rcu_read_unlock();
-                return ret;
+                goto put_old_opp;
         }
 
         dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n", __func__,
@@ -748,8 +664,8 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 
         /* Only frequency scaling */
         if (!regulators) {
-                rcu_read_unlock();
-                return _generic_set_opp_clk_only(dev, clk, old_freq, freq);
+                ret = _generic_set_opp_clk_only(dev, clk, old_freq, freq);
+                goto put_opps;
         }
 
         if (opp_table->set_opp)
@@ -773,28 +689,26 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
         data->new_opp.rate = freq;
         memcpy(data->new_opp.supplies, opp->supplies, size);
 
-        rcu_read_unlock();
+        ret = set_opp(data);
 
-        return set_opp(data);
+put_opps:
+        dev_pm_opp_put(opp);
+put_old_opp:
+        if (!IS_ERR(old_opp))
+                dev_pm_opp_put(old_opp);
+put_opp_table:
+        dev_pm_opp_put_opp_table(opp_table);
+        return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
 
 /* OPP-dev Helpers */
-static void _kfree_opp_dev_rcu(struct rcu_head *head)
-{
-        struct opp_device *opp_dev;
-
-        opp_dev = container_of(head, struct opp_device, rcu_head);
-        kfree_rcu(opp_dev, rcu_head);
-}
-
 static void _remove_opp_dev(struct opp_device *opp_dev,
                             struct opp_table *opp_table)
 {
         opp_debug_unregister(opp_dev, opp_table);
         list_del(&opp_dev->node);
-        call_srcu(&opp_table->srcu_head.srcu, &opp_dev->rcu_head,
-                  _kfree_opp_dev_rcu);
+        kfree(opp_dev);
 }
 
 struct opp_device *_add_opp_dev(const struct device *dev,
@@ -809,7 +723,7 @@ struct opp_device *_add_opp_dev(const struct device *dev,
 
         /* Initialize opp-dev */
         opp_dev->dev = dev;
-        list_add_rcu(&opp_dev->node, &opp_table->dev_list);
+        list_add(&opp_dev->node, &opp_table->dev_list);
 
         /* Create debugfs entries for the opp_table */
         ret = opp_debug_register(opp_dev, opp_table);
@@ -820,26 +734,12 @@ struct opp_device *_add_opp_dev(const struct device *dev,
         return opp_dev;
 }
 
-/**
- * _add_opp_table() - Find 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 opp_table pointer if success, else NULL.
- */
-static struct opp_table *_add_opp_table(struct device *dev)
+static struct opp_table *_allocate_opp_table(struct device *dev)
 {
         struct opp_table *opp_table;
         struct opp_device *opp_dev;
         int ret;
 
-        /* Check for existing table for 'dev' first */
-        opp_table = _find_opp_table(dev);
-        if (!IS_ERR(opp_table))
-                return opp_table;
-
         /*
          * Allocate a new OPP table. In the infrequent case where a new
          * device is needed to be added, we pay this penalty.
@@ -867,50 +767,45 @@ static struct opp_table *_add_opp_table(struct device *dev)
                                 ret);
         }
 
-        srcu_init_notifier_head(&opp_table->srcu_head);
+        BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
         INIT_LIST_HEAD(&opp_table->opp_list);
+        mutex_init(&opp_table->lock);
+        kref_init(&opp_table->kref);
 
         /* Secure the device table modification */
-        list_add_rcu(&opp_table->node, &opp_tables);
+        list_add(&opp_table->node, &opp_tables);
         return opp_table;
 }
 
-/**
- * _kfree_device_rcu() - Free opp_table RCU handler
- * @head:       RCU head
- */
-static void _kfree_device_rcu(struct rcu_head *head)
+void _get_opp_table_kref(struct opp_table *opp_table)
 {
-        struct opp_table *opp_table = container_of(head, struct opp_table,
-                                                   rcu_head);
-
-        kfree_rcu(opp_table, rcu_head);
+        kref_get(&opp_table->kref);
 }
 
-/**
- * _remove_opp_table() - Removes a OPP table
- * @opp_table: OPP table to be removed.
- *
- * Removes/frees OPP table if it doesn't contain any OPPs.
- */
-static void _remove_opp_table(struct opp_table *opp_table)
+struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
 {
-        struct opp_device *opp_dev;
+        struct opp_table *opp_table;
 
-        if (!list_empty(&opp_table->opp_list))
-                return;
+        /* Hold our table modification lock here */
+        mutex_lock(&opp_table_lock);
 
-        if (opp_table->supported_hw)
-                return;
+        opp_table = _find_opp_table_unlocked(dev);
+        if (!IS_ERR(opp_table))
+                goto unlock;
 
-        if (opp_table->prop_name)
-                return;
+        opp_table = _allocate_opp_table(dev);
 
-        if (opp_table->regulators)
-                return;
+unlock:
+        mutex_unlock(&opp_table_lock);
 
-        if (opp_table->set_opp)
-                return;
+        return opp_table;
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_table);
+
+static void _opp_table_kref_release(struct kref *kref)
+{
+        struct opp_table *opp_table = container_of(kref, struct opp_table, kref);
+        struct opp_device *opp_dev;
 
         /* Release clk */
         if (!IS_ERR(opp_table->clk))
@@ -924,63 +819,60 @@ static void _remove_opp_table(struct opp_table *opp_table)
         /* dev_list must be empty now */
         WARN_ON(!list_empty(&opp_table->dev_list));
 
-        list_del_rcu(&opp_table->node);
-        call_srcu(&opp_table->srcu_head.srcu, &opp_table->rcu_head,
-                  _kfree_device_rcu);
+        mutex_destroy(&opp_table->lock);
+        list_del(&opp_table->node);
+        kfree(opp_table);
+
+        mutex_unlock(&opp_table_lock);
 }
 
-/**
- * _kfree_opp_rcu() - Free OPP RCU handler
- * @head:       RCU head
- */
-static void _kfree_opp_rcu(struct rcu_head *head)
+void dev_pm_opp_put_opp_table(struct opp_table *opp_table)
 {
-        struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
+        kref_put_mutex(&opp_table->kref, _opp_table_kref_release,
+                       &opp_table_lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put_opp_table);
 
-        kfree_rcu(opp, rcu_head);
+void _opp_free(struct dev_pm_opp *opp)
+{
+        kfree(opp);
 }
 
-/**
- * _opp_remove()  - Remove an OPP from a table definition
- * @opp_table:  points back to the opp_table 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 table.
- *
- * Locking: The internal opp_table and opp structures are RCU protected.
- * It is assumed that the caller holds required mutex for an RCU updater
- * strategy.
- */
-void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp,
-                 bool notify)
+static void _opp_kref_release(struct kref *kref)
 {
+        struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
+        struct opp_table *opp_table = opp->opp_table;
+
         /*
          * Notify the changes in the availability of the operable
          * frequency/voltage list.
          */
-        if (notify)
-                srcu_notifier_call_chain(&opp_table->srcu_head,
-                                         OPP_EVENT_REMOVE, opp);
+        blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_REMOVE, opp);
         opp_debug_remove_one(opp);
-        list_del_rcu(&opp->node);
-        call_srcu(&opp_table->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
+        list_del(&opp->node);
+        kfree(opp);
 
-        _remove_opp_table(opp_table);
+        mutex_unlock(&opp_table->lock);
+        dev_pm_opp_put_opp_table(opp_table);
+}
+
+static void dev_pm_opp_get(struct dev_pm_opp *opp)
+{
+        kref_get(&opp->kref);
 }
 
+void dev_pm_opp_put(struct dev_pm_opp *opp)
+{
+        kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);
+}
+EXPORT_SYMBOL_GPL(dev_pm_opp_put);
+
 /**
  * dev_pm_opp_remove()  - Remove an OPP from OPP table
  * @dev:        device for which we do this operation
  * @freq:       OPP to remove with matching 'freq'
  *
  * This function removes an opp from the opp table.
- *
- * Locking: The internal opp_table 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)
 {
@@ -988,12 +880,11 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
         struct opp_table *opp_table;
         bool found = false;
 
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
-
         opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table))
-                goto unlock;
+                return;
+
+        mutex_lock(&opp_table->lock);
 
         list_for_each_entry(opp, &opp_table->opp_list, node) {
                 if (opp->rate == freq) {
@@ -1002,28 +893,23 @@ void dev_pm_opp_remove(struct device *dev, unsigned long freq)
                 }
         }
 
-        if (!found) {
+        mutex_unlock(&opp_table->lock);
+
+        if (found) {
+                dev_pm_opp_put(opp);
+        } else {
                 dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
                          __func__, freq);
-                goto unlock;
         }
 
-        _opp_remove(opp_table, opp, true);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
 
-struct dev_pm_opp *_allocate_opp(struct device *dev,
-                                 struct opp_table **opp_table)
+struct dev_pm_opp *_opp_allocate(struct opp_table *table)
 {
         struct dev_pm_opp *opp;
         int count, supply_size;
-        struct opp_table *table;
-
-        table = _add_opp_table(dev);
-        if (!table)
-                return NULL;
 
         /* Allocate space for at least one supply */
         count = table->regulator_count ? table->regulator_count : 1;
@@ -1031,17 +917,13 @@ struct dev_pm_opp *_allocate_opp(struct device *dev,
 
         /* allocate new OPP node and supplies structures */
         opp = kzalloc(sizeof(*opp) + supply_size, GFP_KERNEL);
-        if (!opp) {
-                kfree(table);
+        if (!opp)
                 return NULL;
-        }
 
         /* Put the supplies at the end of the OPP structure as an empty array */
         opp->supplies = (struct dev_pm_opp_supply *)(opp + 1);
         INIT_LIST_HEAD(&opp->node);
 
-        *opp_table = table;
-
         return opp;
 }
 
@@ -1067,11 +949,21 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
         return true;
 }
 
+/*
+ * Returns:
+ * 0: On success. And appropriate error message for duplicate OPPs.
+ * -EBUSY: For OPP with same freq/volt and is available. The callers of
+ *  _opp_add() must return 0 if they receive -EBUSY from it. This is to make
+ *  sure we don't print error messages unnecessarily if different parts of
+ *  kernel try to initialize the OPP table.
+ * -EEXIST: For OPP with same freq but different volt or is unavailable. This
+ *  should be considered an error by the callers of _opp_add().
+ */
 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
              struct opp_table *opp_table)
 {
         struct dev_pm_opp *opp;
-        struct list_head *head = &opp_table->opp_list;
+        struct list_head *head;
         int ret;
 
         /*
@@ -1082,7 +974,10 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
          * loop, don't replace it with head otherwise it will become an infinite
          * loop.
          */
-        list_for_each_entry_rcu(opp, &opp_table->opp_list, node) {
+        mutex_lock(&opp_table->lock);
+        head = &opp_table->opp_list;
+
+        list_for_each_entry(opp, &opp_table->opp_list, node) {
                 if (new_opp->rate > opp->rate) {
                         head = &opp->node;
                         continue;
@@ -1098,12 +993,21 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
                          new_opp->supplies[0].u_volt, new_opp->available);
 
                 /* Should we compare voltages for all regulators here ? */
-                return opp->available &&
-                       new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? 0 : -EEXIST;
+                ret = opp->available &&
+                      new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;
+
+                mutex_unlock(&opp_table->lock);
+                return ret;
         }
 
+        list_add(&new_opp->node, head);
+        mutex_unlock(&opp_table->lock);
+
         new_opp->opp_table = opp_table;
-        list_add_rcu(&new_opp->node, head);
+        kref_init(&new_opp->kref);
+
+        /* Get a reference to the OPP table */
+        _get_opp_table_kref(opp_table);
 
         ret = opp_debug_create_one(new_opp, opp_table);
         if (ret)
@@ -1121,6 +1025,7 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
 
 /**
  * _opp_add_v1() - Allocate a OPP based on v1 bindings.
+ * @opp_table:  OPP table
  * @dev:        device for which we do this operation
  * @freq:       Frequency in Hz for this OPP
  * @u_volt:     Voltage in uVolts for this OPP
@@ -1133,12 +1038,6 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
  * 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 opp_table 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
@@ -1146,22 +1045,16 @@ int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
  *              Duplicate OPPs (both freq and volt are same) and !opp->available
  * -ENOMEM      Memory allocation failure
  */
-int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
-                bool dynamic)
+int _opp_add_v1(struct opp_table *opp_table, struct device *dev,
+                unsigned long freq, long u_volt, bool dynamic)
 {
-        struct opp_table *opp_table;
         struct dev_pm_opp *new_opp;
         unsigned long tol;
         int ret;
 
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
-
-        new_opp = _allocate_opp(dev, &opp_table);
-        if (!new_opp) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        new_opp = _opp_allocate(opp_table);
+        if (!new_opp)
+                return -ENOMEM;
 
         /* populate the opp table */
         new_opp->rate = freq;
@@ -1173,22 +1066,23 @@ int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
         new_opp->dynamic = dynamic;
 
         ret = _opp_add(dev, new_opp, opp_table);
-        if (ret)
+        if (ret) {
+                /* Don't return error for duplicate OPPs */
+                if (ret == -EBUSY)
+                        ret = 0;
                 goto free_opp;
-
-        mutex_unlock(&opp_table_lock);
+        }
 
         /*
          * Notify the changes in the availability of the operable
          * frequency/voltage list.
          */
-        srcu_notifier_call_chain(&opp_table->srcu_head, OPP_EVENT_ADD, new_opp);
+        blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
         return 0;
 
 free_opp:
-        _opp_remove(opp_table, new_opp, false);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        _opp_free(new_opp);
+
         return ret;
 }
 
@@ -1202,27 +1096,16 @@ unlock:
  * specify the hierarchy of versions it supports. OPP layer will then enable
  * OPPs, which are available for those versions, based on its 'opp-supported-hw'
  * property.
- *
- * Locking: The internal opp_table 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.
  */
-int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
-                                unsigned int count)
+struct opp_table *dev_pm_opp_set_supported_hw(struct device *dev,
+                        const u32 *versions, unsigned int count)
 {
         struct opp_table *opp_table;
-        int ret = 0;
-
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
+        int ret;
 
-        opp_table = _add_opp_table(dev);
-        if (!opp_table) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return ERR_PTR(-ENOMEM);
 
         /* Make sure there are no concurrent readers while updating opp_table */
         WARN_ON(!list_empty(&opp_table->opp_list));
@@ -1243,65 +1126,40 @@ int dev_pm_opp_set_supported_hw(struct device *dev, const u32 *versions,
         }
 
         opp_table->supported_hw_count = count;
-        mutex_unlock(&opp_table_lock);
-        return 0;
+
+        return opp_table;
 
 err:
-        _remove_opp_table(opp_table);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 
-        return ret;
+        return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_set_supported_hw);
 
 /**
  * dev_pm_opp_put_supported_hw() - Releases resources blocked for supported hw
- * @dev: Device for which supported-hw has to be put.
+ * @opp_table: OPP table returned by dev_pm_opp_set_supported_hw().
  *
  * This is required only for the V2 bindings, and is called for a matching
  * dev_pm_opp_set_supported_hw(). Until this is called, the opp_table structure
  * will not be freed.
- *
- * Locking: The internal opp_table 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_put_supported_hw(struct device *dev)
+void dev_pm_opp_put_supported_hw(struct opp_table *opp_table)
 {
-        struct opp_table *opp_table;
-
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
-
-        /* Check for existing table for 'dev' first */
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                dev_err(dev, "Failed to find opp_table: %ld\n",
-                        PTR_ERR(opp_table));
-                goto unlock;
-        }
-
         /* Make sure there are no concurrent readers while updating opp_table */
         WARN_ON(!list_empty(&opp_table->opp_list));
 
         if (!opp_table->supported_hw) {
-                dev_err(dev, "%s: Doesn't have supported hardware list\n",
-                        __func__);
-                goto unlock;
+                pr_err("%s: Doesn't have supported hardware list\n",
+                       __func__);
+                return;
         }
 
         kfree(opp_table->supported_hw);
         opp_table->supported_hw = NULL;
         opp_table->supported_hw_count = 0;
 
-        /* Try freeing opp_table if this was the last blocking resource */
-        _remove_opp_table(opp_table);
-
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_put_supported_hw);
 
@@ -1314,26 +1172,15 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_put_supported_hw);
  * specify the extn to be used for certain property names. The properties to
  * which the extension will apply are opp-microvolt and opp-microamp. OPP core
  * should postfix the property name with -<name> while looking for them.
- *
- * Locking: The internal opp_table 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.
  */
-int dev_pm_opp_set_prop_name(struct device *dev, const char *name)
+struct opp_table *dev_pm_opp_set_prop_name(struct device *dev, const char *name)
 {
         struct opp_table *opp_table;
-        int ret = 0;
-
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
+        int ret;
 
-        opp_table = _add_opp_table(dev);
-        if (!opp_table) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return ERR_PTR(-ENOMEM);
 
         /* Make sure there are no concurrent readers while updating opp_table */
         WARN_ON(!list_empty(&opp_table->opp_list));
@@ -1352,63 +1199,37 @@ int dev_pm_opp_set_prop_name(struct device *dev, const char *name)
                 goto err;
         }
 
-        mutex_unlock(&opp_table_lock);
-        return 0;
+        return opp_table;
 
 err:
-        _remove_opp_table(opp_table);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 
-        return ret;
+        return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_set_prop_name);
 
 /**
  * dev_pm_opp_put_prop_name() - Releases resources blocked for prop-name
- * @dev: Device for which the prop-name has to be put.
+ * @opp_table: OPP table returned by dev_pm_opp_set_prop_name().
  *
  * This is required only for the V2 bindings, and is called for a matching
  * dev_pm_opp_set_prop_name(). Until this is called, the opp_table structure
  * will not be freed.
- *
- * Locking: The internal opp_table 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_put_prop_name(struct device *dev)
+void dev_pm_opp_put_prop_name(struct opp_table *opp_table)
 {
-        struct opp_table *opp_table;
-
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
-
-        /* Check for existing table for 'dev' first */
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                dev_err(dev, "Failed to find opp_table: %ld\n",
-                        PTR_ERR(opp_table));
-                goto unlock;
-        }
-
         /* Make sure there are no concurrent readers while updating opp_table */
         WARN_ON(!list_empty(&opp_table->opp_list));
 
         if (!opp_table->prop_name) {
-                dev_err(dev, "%s: Doesn't have a prop-name\n", __func__);
-                goto unlock;
+                pr_err("%s: Doesn't have a prop-name\n", __func__);
+                return;
         }
 
         kfree(opp_table->prop_name);
         opp_table->prop_name = NULL;
 
-        /* Try freeing opp_table if this was the last blocking resource */
-        _remove_opp_table(opp_table);
-
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_put_prop_name);
 
@@ -1455,12 +1276,6 @@ static void _free_set_opp_data(struct opp_table *opp_table)
  * well.
  *
  * This must be called before any OPPs are initialized for the device.
- *
- * Locking: The internal opp_table 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.
  */
 struct opp_table *dev_pm_opp_set_regulators(struct device *dev,
                                             const char * const names[],
@@ -1470,13 +1285,9 @@ struct opp_table *dev_pm_opp_set_regulators(struct device *dev,
         struct regulator *reg;
         int ret, i;
 
-        mutex_lock(&opp_table_lock);
-
-        opp_table = _add_opp_table(dev);
-        if (!opp_table) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return ERR_PTR(-ENOMEM);
 
         /* This should be called before OPPs are initialized */
         if (WARN_ON(!list_empty(&opp_table->opp_list))) {
@@ -1518,7 +1329,6 @@ struct opp_table *dev_pm_opp_set_regulators(struct device *dev,
         if (ret)
                 goto free_regulators;
 
-        mutex_unlock(&opp_table_lock);
         return opp_table;
 
 free_regulators:
@@ -1529,9 +1339,7 @@ free_regulators:
         opp_table->regulators = NULL;
         opp_table->regulator_count = 0;
 err:
-        _remove_opp_table(opp_table);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 
         return ERR_PTR(ret);
 }
@@ -1540,22 +1348,14 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_set_regulators);
 /**
  * dev_pm_opp_put_regulators() - Releases resources blocked for regulator
  * @opp_table: OPP table returned from dev_pm_opp_set_regulators().
- *
- * Locking: The internal opp_table 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_put_regulators(struct opp_table *opp_table)
 {
         int i;
 
-        mutex_lock(&opp_table_lock);
-
         if (!opp_table->regulators) {
                 pr_err("%s: Doesn't have regulators set\n", __func__);
-                goto unlock;
+                return;
         }
 
         /* Make sure there are no concurrent readers while updating opp_table */
@@ -1570,11 +1370,7 @@ void dev_pm_opp_put_regulators(struct opp_table *opp_table)
         opp_table->regulators = NULL;
         opp_table->regulator_count = 0;
 
-        /* Try freeing opp_table if this was the last blocking resource */
-        _remove_opp_table(opp_table);
-
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulators);
 
@@ -1587,29 +1383,19 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_put_regulators);
  * regulators per device), instead of the generic OPP set rate helper.
  *
  * This must be called before any OPPs are initialized for the device.
- *
- * Locking: The internal opp_table 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.
  */
-int dev_pm_opp_register_set_opp_helper(struct device *dev,
+struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev,
                         int (*set_opp)(struct dev_pm_set_opp_data *data))
 {
         struct opp_table *opp_table;
         int ret;
 
         if (!set_opp)
-                return -EINVAL;
-
-        mutex_lock(&opp_table_lock);
+                return ERR_PTR(-EINVAL);
 
-        opp_table = _add_opp_table(dev);
-        if (!opp_table) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return ERR_PTR(-ENOMEM);
 
         /* This should be called before OPPs are initialized */
         if (WARN_ON(!list_empty(&opp_table->opp_list))) {
@@ -1625,47 +1411,28 @@ int dev_pm_opp_register_set_opp_helper(struct device *dev,
 
         opp_table->set_opp = set_opp;
 
-        mutex_unlock(&opp_table_lock);
-        return 0;
+        return opp_table;
 
 err:
-        _remove_opp_table(opp_table);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 
-        return ret;
+        return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_register_set_opp_helper);
 
 /**
  * dev_pm_opp_register_put_opp_helper() - Releases resources blocked for
  *                                         set_opp helper
- * @dev: Device for which custom set_opp helper has to be cleared.
+ * @opp_table: OPP table returned from dev_pm_opp_register_set_opp_helper().
  *
- * Locking: The internal opp_table 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.
+ * Release resources blocked for platform specific set_opp helper.
  */
-void dev_pm_opp_register_put_opp_helper(struct device *dev)
+void dev_pm_opp_register_put_opp_helper(struct opp_table *opp_table)
 {
-        struct opp_table *opp_table;
-
-        mutex_lock(&opp_table_lock);
-
-        /* Check for existing table for 'dev' first */
-        opp_table = _find_opp_table(dev);
-        if (IS_ERR(opp_table)) {
-                dev_err(dev, "Failed to find opp_table: %ld\n",
-                        PTR_ERR(opp_table));
-                goto unlock;
-        }
-
         if (!opp_table->set_opp) {
-                dev_err(dev, "%s: Doesn't have custom set_opp helper set\n",
-                        __func__);
-                goto unlock;
+                pr_err("%s: Doesn't have custom set_opp helper set\n",
+                       __func__);
+                return;
         }
 
         /* Make sure there are no concurrent readers while updating opp_table */
@@ -1673,11 +1440,7 @@ void dev_pm_opp_register_put_opp_helper(struct device *dev)
 
         opp_table->set_opp = NULL;
 
-        /* Try freeing opp_table if this was the last blocking resource */
-        _remove_opp_table(opp_table);
-
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_register_put_opp_helper);
 
@@ -1691,12 +1454,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_register_put_opp_helper);
  * The opp is made available by default and it can be controlled using
  * dev_pm_opp_enable/disable functions.
  *
- * Locking: The internal opp_table 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
@@ -1706,7 +1463,17 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_register_put_opp_helper);
  */
 int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
 {
-        return _opp_add_v1(dev, freq, u_volt, true);
+        struct opp_table *opp_table;
+        int ret;
+
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return -ENOMEM;
+
+        ret = _opp_add_v1(opp_table, dev, freq, u_volt, true);
+
+        dev_pm_opp_put_opp_table(opp_table);
+        return ret;
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_add);
 
@@ -1716,41 +1483,30 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_add);
  * @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.
+ * Set the availability of an OPP, 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 opp_table 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 opp_table *opp_table;
-        struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
+        struct dev_pm_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(&opp_table_lock);
-
         /* Find the opp_table */
         opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table)) {
                 r = PTR_ERR(opp_table);
                 dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
-                goto unlock;
+                return r;
         }
 
+        mutex_lock(&opp_table->lock);
+
         /* Do we have the frequency? */
         list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
                 if (tmp_opp->rate == freq) {
@@ -1758,6 +1514,7 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
                         break;
                 }
         }
+
         if (IS_ERR(opp)) {
                 r = PTR_ERR(opp);
                 goto unlock;
@@ -1766,29 +1523,20 @@ static int _opp_set_availability(struct device *dev, unsigned long freq,
         /* 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(&opp_table_lock);
-        call_srcu(&opp_table->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
+        opp->available = availability_req;
 
         /* Notify the change of the OPP availability */
         if (availability_req)
-                srcu_notifier_call_chain(&opp_table->srcu_head,
-                                         OPP_EVENT_ENABLE, new_opp);
+                blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ENABLE,
+                                             opp);
         else
-                srcu_notifier_call_chain(&opp_table->srcu_head,
-                                         OPP_EVENT_DISABLE, new_opp);
-
-        return 0;
+                blocking_notifier_call_chain(&opp_table->head,
+                                             OPP_EVENT_DISABLE, opp);
 
 unlock:
-        mutex_unlock(&opp_table_lock);
-        kfree(new_opp);
+        mutex_unlock(&opp_table->lock);
+        dev_pm_opp_put_opp_table(opp_table);
         return r;
 }
 
@@ -1801,12 +1549,6 @@ unlock:
  * 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 opp_table 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.
@@ -1827,12 +1569,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
  * 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 opp_table 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.
@@ -1844,41 +1580,78 @@ int dev_pm_opp_disable(struct device *dev, unsigned long freq)
 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 OPP table.
+ * dev_pm_opp_register_notifier() - Register OPP notifier for the device
+ * @dev:        Device for which notifier needs to be registered
+ * @nb:         Notifier block to be registered
  *
- * 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.
+ * Return: 0 on success or a negative error value.
+ */
+int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb)
+{
+        struct opp_table *opp_table;
+        int ret;
+
+        opp_table = _find_opp_table(dev);
+        if (IS_ERR(opp_table))
+                return PTR_ERR(opp_table);
+
+        ret = blocking_notifier_chain_register(&opp_table->head, nb);
+
+        dev_pm_opp_put_opp_table(opp_table);
+
+        return ret;
+}
+EXPORT_SYMBOL(dev_pm_opp_register_notifier);
+
+/**
+ * dev_pm_opp_unregister_notifier() - Unregister OPP notifier for the device
+ * @dev:        Device for which notifier needs to be unregistered
+ * @nb:         Notifier block to be unregistered
  *
- * Locking: This function must be called under rcu_read_lock(). opp_table 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.
+ * Return: 0 on success or a negative error value.
  */
-struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
+int dev_pm_opp_unregister_notifier(struct device *dev,
+                                   struct notifier_block *nb)
 {
-        struct opp_table *opp_table = _find_opp_table(dev);
+        struct opp_table *opp_table;
+        int ret;
 
+        opp_table = _find_opp_table(dev);
         if (IS_ERR(opp_table))
-                return ERR_CAST(opp_table); /* matching type */
+                return PTR_ERR(opp_table);
+
+        ret = blocking_notifier_chain_unregister(&opp_table->head, nb);
 
-        return &opp_table->srcu_head;
+        dev_pm_opp_put_opp_table(opp_table);
+
+        return ret;
 }
-EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
+EXPORT_SYMBOL(dev_pm_opp_unregister_notifier);
 
 /*
  * Free OPPs either created using static entries present in DT or even the
  * dynamically added entries based on remove_all param.
  */
-void _dev_pm_opp_remove_table(struct device *dev, bool remove_all)
+void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev,
+                              bool remove_all)
 {
-        struct opp_table *opp_table;
         struct dev_pm_opp *opp, *tmp;
 
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
+        /* Find if opp_table manages a single device */
+        if (list_is_singular(&opp_table->dev_list)) {
+                /* Free static OPPs */
+                list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) {
+                        if (remove_all || !opp->dynamic)
+                                dev_pm_opp_put(opp);
+                }
+        } else {
+                _remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table);
+        }
+}
+
+void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all)
+{
+        struct opp_table *opp_table;
 
         /* Check for existing table for 'dev' */
         opp_table = _find_opp_table(dev);
@@ -1890,22 +1663,12 @@ void _dev_pm_opp_remove_table(struct device *dev, bool remove_all)
                              IS_ERR_OR_NULL(dev) ?
                                         "Invalid device" : dev_name(dev),
                              error);
-                goto unlock;
+                return;
         }
 
-        /* Find if opp_table manages a single device */
-        if (list_is_singular(&opp_table->dev_list)) {
-                /* Free static OPPs */
-                list_for_each_entry_safe(opp, tmp, &opp_table->opp_list, node) {
-                        if (remove_all || !opp->dynamic)
-                                _opp_remove(opp_table, opp, true);
-                }
-        } else {
-                _remove_opp_dev(_find_opp_dev(dev, opp_table), opp_table);
-        }
+        _dev_pm_opp_remove_table(opp_table, dev, remove_all);
 
-unlock:
-        mutex_unlock(&opp_table_lock);
+        dev_pm_opp_put_opp_table(opp_table);
 }
 
 /**
@@ -1914,15 +1677,9 @@ unlock:
  *
  * Free both OPPs created using static entries present in DT and the
  * dynamically added entries.
- *
- * Locking: The internal opp_table 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_remove_table(struct device *dev)
 {
-        _dev_pm_opp_remove_table(dev, true);
+        _dev_pm_opp_find_and_remove_table(dev, true);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_remove_table);
diff --git a/drivers/base/power/opp/cpu.c b/drivers/base/power/opp/cpu.c
index 8c3434bdb26d..2d87bc1adf38 100644
--- a/drivers/base/power/opp/cpu.c
+++ b/drivers/base/power/opp/cpu.c
@@ -42,11 +42,6 @@
  *
  * WARNING: It is  important for the callers to ensure refreshing their copy of
  * the table if any of the mentioned functions have been invoked in the interim.
- *
- * Locking: The internal opp_table and opp structures are RCU protected.
- * Since we just use the regular accessor functions to access the internal data
- * structures, we use RCU read lock inside this function. As a result, users of
- * this function DONOT need to use explicit locks for invoking.
  */
 int dev_pm_opp_init_cpufreq_table(struct device *dev,
                                   struct cpufreq_frequency_table **table)
@@ -56,19 +51,13 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
         int i, max_opps, ret = 0;
         unsigned long rate;
 
-        rcu_read_lock();
-
         max_opps = dev_pm_opp_get_opp_count(dev);
-        if (max_opps <= 0) {
-                ret = max_opps ? max_opps : -ENODATA;
-                goto out;
-        }
+        if (max_opps <= 0)
+                return max_opps ? max_opps : -ENODATA;
 
         freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
-        if (!freq_table) {
-                ret = -ENOMEM;
-                goto out;
-        }
+        if (!freq_table)
+                return -ENOMEM;
 
         for (i = 0, rate = 0; i < max_opps; i++, rate++) {
                 /* find next rate */
@@ -83,6 +72,8 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
                 /* Is Boost/turbo opp ? */
                 if (dev_pm_opp_is_turbo(opp))
                         freq_table[i].flags = CPUFREQ_BOOST_FREQ;
+
+                dev_pm_opp_put(opp);
         }
 
         freq_table[i].driver_data = i;
@@ -91,7 +82,6 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
         *table = &freq_table[0];
 
 out:
-        rcu_read_unlock();
         if (ret)
                 kfree(freq_table);
 
@@ -147,12 +137,6 @@ void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of)
  * This removes the OPP tables for CPUs present in the @cpumask.
  * This should be used to remove all the OPPs entries associated with
  * the cpus in @cpumask.
- *
- * Locking: The internal opp_table 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_cpumask_remove_table(const struct cpumask *cpumask)
 {
@@ -169,12 +153,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_cpumask_remove_table);
  * @cpumask.
  *
  * Returns -ENODEV if OPP table isn't already present.
- *
- * Locking: The internal opp_table 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.
  */
 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
                                 const struct cpumask *cpumask)
@@ -184,13 +162,9 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
         struct device *dev;
         int cpu, ret = 0;
 
-        mutex_lock(&opp_table_lock);
-
         opp_table = _find_opp_table(cpu_dev);
-        if (IS_ERR(opp_table)) {
-                ret = PTR_ERR(opp_table);
-                goto unlock;
-        }
+        if (IS_ERR(opp_table))
+                return PTR_ERR(opp_table);
 
         for_each_cpu(cpu, cpumask) {
                 if (cpu == cpu_dev->id)
@@ -213,8 +187,8 @@ int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
                 /* Mark opp-table as multiple CPUs are sharing it now */
                 opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
         }
-unlock:
-        mutex_unlock(&opp_table_lock);
+
+        dev_pm_opp_put_opp_table(opp_table);
 
         return ret;
 }
@@ -229,12 +203,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
  *
  * Returns -ENODEV if OPP table isn't already present and -EINVAL if the OPP
  * table's status is access-unknown.
- *
- * Locking: The internal opp_table 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.
  */
 int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
 {
@@ -242,17 +210,13 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
         struct opp_table *opp_table;
         int ret = 0;
 
-        mutex_lock(&opp_table_lock);
-
         opp_table = _find_opp_table(cpu_dev);
-        if (IS_ERR(opp_table)) {
-                ret = PTR_ERR(opp_table);
-                goto unlock;
-        }
+        if (IS_ERR(opp_table))
+                return PTR_ERR(opp_table);
 
         if (opp_table->shared_opp == OPP_TABLE_ACCESS_UNKNOWN) {
                 ret = -EINVAL;
-                goto unlock;
+                goto put_opp_table;
         }
 
         cpumask_clear(cpumask);
@@ -264,8 +228,8 @@ int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask)
                 cpumask_set_cpu(cpu_dev->id, cpumask);
         }
 
-unlock:
-        mutex_unlock(&opp_table_lock);
+put_opp_table:
+        dev_pm_opp_put_opp_table(opp_table);
 
         return ret;
 }
diff --git a/drivers/base/power/opp/of.c b/drivers/base/power/opp/of.c
index 3f7d2591b173..779428676f63 100644
--- a/drivers/base/power/opp/of.c
+++ b/drivers/base/power/opp/of.c
@@ -24,9 +24,11 @@
 
 static struct opp_table *_managed_opp(const struct device_node *np)
 {
-        struct opp_table *opp_table;
+        struct opp_table *opp_table, *managed_table = NULL;
+
+        mutex_lock(&opp_table_lock);
 
-        list_for_each_entry_rcu(opp_table, &opp_tables, node) {
+        list_for_each_entry(opp_table, &opp_tables, node) {
                 if (opp_table->np == np) {
                         /*
                          * Multiple devices can point to the same OPP table and
@@ -35,14 +37,18 @@ static struct opp_table *_managed_opp(const struct device_node *np)
                          * But the OPPs will be considered as shared only if the
                          * OPP table contains a "opp-shared" property.
                          */
-                        if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED)
-                                return opp_table;
+                        if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
+                                _get_opp_table_kref(opp_table);
+                                managed_table = opp_table;
+                        }
 
-                        return NULL;
+                        break;
                 }
         }
 
-        return NULL;
+        mutex_unlock(&opp_table_lock);
+
+        return managed_table;
 }
 
 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev)
@@ -229,34 +235,28 @@ free_microvolt:
  * @dev:        device pointer used to lookup OPP table.
  *
  * Free OPPs created using static entries present in DT.
- *
- * Locking: The internal opp_table 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)
 {
-        _dev_pm_opp_remove_table(dev, false);
+        _dev_pm_opp_find_and_remove_table(dev, false);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
 /* Returns opp descriptor node for a device, caller must do of_node_put() */
-static struct device_node *_of_get_opp_desc_node(struct device *dev)
+struct device_node *dev_pm_opp_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);
 }
+EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);
 
 /**
  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
+ * @opp_table:  OPP table
  * @dev:        device for which we do this operation
  * @np:         device node
  *
@@ -264,12 +264,6 @@ static struct device_node *_of_get_opp_desc_node(struct device *dev)
  * opp can be controlled using dev_pm_opp_enable/disable functions and may be
  * removed by dev_pm_opp_remove.
  *
- * Locking: The internal opp_table 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
@@ -278,22 +272,17 @@ static struct device_node *_of_get_opp_desc_node(struct device *dev)
  * -ENOMEM      Memory allocation failure
  * -EINVAL      Failed parsing the OPP node
  */
-static int _opp_add_static_v2(struct device *dev, struct device_node *np)
+static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
+                              struct device_node *np)
 {
-        struct opp_table *opp_table;
         struct dev_pm_opp *new_opp;
         u64 rate;
         u32 val;
         int ret;
 
-        /* Hold our table modification lock here */
-        mutex_lock(&opp_table_lock);
-
-        new_opp = _allocate_opp(dev, &opp_table);
-        if (!new_opp) {
-                ret = -ENOMEM;
-                goto unlock;
-        }
+        new_opp = _opp_allocate(opp_table);
+        if (!new_opp)
+                return -ENOMEM;
 
         ret = of_property_read_u64(np, "opp-hz", &rate);
         if (ret < 0) {
@@ -327,8 +316,12 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
                 goto free_opp;
 
         ret = _opp_add(dev, new_opp, opp_table);
-        if (ret)
+        if (ret) {
+                /* Don't return error for duplicate OPPs */
+                if (ret == -EBUSY)
+                        ret = 0;
                 goto free_opp;
+        }
 
         /* OPP to select on device suspend */
         if (of_property_read_bool(np, "opp-suspend")) {
@@ -345,8 +338,6 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
         if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
                 opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
 
-        mutex_unlock(&opp_table_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->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
@@ -356,13 +347,12 @@ static int _opp_add_static_v2(struct device *dev, struct device_node *np)
          * Notify the changes in the availability of the operable
          * frequency/voltage list.
          */
-        srcu_notifier_call_chain(&opp_table->srcu_head, OPP_EVENT_ADD, new_opp);
+        blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
         return 0;
 
 free_opp:
-        _opp_remove(opp_table, new_opp, false);
-unlock:
-        mutex_unlock(&opp_table_lock);
+        _opp_free(new_opp);
+
         return ret;
 }
 
@@ -373,41 +363,35 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
         struct opp_table *opp_table;
         int ret = 0, count = 0;
 
-        mutex_lock(&opp_table_lock);
-
         opp_table = _managed_opp(opp_np);
         if (opp_table) {
                 /* OPPs are already managed */
                 if (!_add_opp_dev(dev, opp_table))
                         ret = -ENOMEM;
-                mutex_unlock(&opp_table_lock);
-                return ret;
+                goto put_opp_table;
         }
-        mutex_unlock(&opp_table_lock);
+
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return -ENOMEM;
 
         /* We have opp-table 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);
+                ret = _opp_add_static_v2(opp_table, dev, np);
                 if (ret) {
                         dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
                                 ret);
-                        goto free_table;
+                        _dev_pm_opp_remove_table(opp_table, dev, false);
+                        goto put_opp_table;
                 }
         }
 
         /* There should be one of more OPP defined */
-        if (WARN_ON(!count))
-                return -ENOENT;
-
-        mutex_lock(&opp_table_lock);
-
-        opp_table = _find_opp_table(dev);
-        if (WARN_ON(IS_ERR(opp_table))) {
-                ret = PTR_ERR(opp_table);
-                mutex_unlock(&opp_table_lock);
-                goto free_table;
+        if (WARN_ON(!count)) {
+                ret = -ENOENT;
+                goto put_opp_table;
         }
 
         opp_table->np = opp_np;
@@ -416,12 +400,8 @@ static int _of_add_opp_table_v2(struct device *dev, struct device_node *opp_np)
         else
                 opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
 
-        mutex_unlock(&opp_table_lock);
-
-        return 0;
-
-free_table:
-        dev_pm_opp_of_remove_table(dev);
+put_opp_table:
+        dev_pm_opp_put_opp_table(opp_table);
 
         return ret;
 }
@@ -429,9 +409,10 @@ free_table:
 /* Initializes OPP tables based on old-deprecated bindings */
 static int _of_add_opp_table_v1(struct device *dev)
 {
+        struct opp_table *opp_table;
         const struct property *prop;
         const __be32 *val;
-        int nr;
+        int nr, ret = 0;
 
         prop = of_find_property(dev->of_node, "operating-points", NULL);
         if (!prop)
@@ -449,18 +430,27 @@ static int _of_add_opp_table_v1(struct device *dev)
                 return -EINVAL;
         }
 
+        opp_table = dev_pm_opp_get_opp_table(dev);
+        if (!opp_table)
+                return -ENOMEM;
+
         val = prop->value;
         while (nr) {
                 unsigned long freq = be32_to_cpup(val++) * 1000;
                 unsigned long volt = be32_to_cpup(val++);
 
-                if (_opp_add_v1(dev, freq, volt, false))
-                        dev_warn(dev, "%s: Failed to add OPP %ld\n",
-                                 __func__, freq);
+                ret = _opp_add_v1(opp_table, dev, freq, volt, false);
+                if (ret) {
+                        dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
+                                __func__, freq, ret);
+                        _dev_pm_opp_remove_table(opp_table, dev, false);
+                        break;
+                }
                 nr -= 2;
         }
 
-        return 0;
+        dev_pm_opp_put_opp_table(opp_table);
+        return ret;
 }
 
 /**
@@ -469,12 +459,6 @@ static int _of_add_opp_table_v1(struct device *dev)
  *
  * Register the initial OPP table with the OPP library for given device.
  *
- * Locking: The internal opp_table 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
@@ -495,7 +479,7 @@ int dev_pm_opp_of_add_table(struct device *dev)
          * 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);
+        opp_np = dev_pm_opp_of_get_opp_desc_node(dev);
         if (!opp_np) {
                 /*
                  * Try old-deprecated bindings for backward compatibility with
@@ -519,12 +503,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
  *
  * This removes the OPP tables for CPUs present in the @cpumask.
  * This should be used only to remove static entries created from DT.
- *
- * Locking: The internal opp_table 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_of_cpumask_remove_table(const struct cpumask *cpumask)
 {
@@ -537,12 +515,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
  * @cpumask:    cpumask for which OPP table needs to be added.
  *
  * This adds the OPP tables for CPUs present in the @cpumask.
- *
- * Locking: The internal opp_table 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.
  */
 int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
 {
@@ -590,12 +562,6 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
  * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
  *
  * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
- *
- * Locking: The internal opp_table 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.
  */
 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
                                    struct cpumask *cpumask)
@@ -605,7 +571,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
         int cpu, ret = 0;
 
         /* Get OPP descriptor node */
-        np = _of_get_opp_desc_node(cpu_dev);
+        np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
         if (!np) {
                 dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
                 return -ENOENT;
@@ -630,7 +596,7 @@ int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
                 }
 
                 /* Get OPP descriptor node */
-                tmp_np = _of_get_opp_desc_node(tcpu_dev);
+                tmp_np = dev_pm_opp_of_get_opp_desc_node(tcpu_dev);
                 if (!tmp_np) {
                         dev_err(tcpu_dev, "%s: Couldn't find opp node.\n",
                                 __func__);
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index af9f2b849a66..166eef990599 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -16,11 +16,11 @@
 
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/kref.h>
 #include <linux/list.h>
 #include <linux/limits.h>
 #include <linux/pm_opp.h>
-#include <linux/rculist.h>
-#include <linux/rcupdate.h>
+#include <linux/notifier.h>
 
 struct clk;
 struct regulator;
@@ -51,11 +51,9 @@ extern struct list_head opp_tables;
  * @node:       opp table node. The nodes are maintained throughout the lifetime
  *              of boot. It is expected only an optimal set of OPPs are
  *              added to the library by the SoC framework.
- *              RCU usage: opp table is traversed with RCU locks. node
- *              modification is possible realtime, hence the modifications
- *              are protected by the opp_table_lock for integrity.
  *              IMPORTANT: the opp nodes should be maintained in increasing
  *              order.
+ * @kref:       for reference count of the OPP.
  * @available:  true/false - marks if this OPP as available or not
  * @dynamic:    not-created from static DT entries.
  * @turbo:      true if turbo (boost) OPP
@@ -65,7 +63,6 @@ extern struct list_head opp_tables;
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  *              frequency from any other OPP's frequency.
  * @opp_table:  points back to the opp_table struct this opp belongs to
- * @rcu_head:   RCU callback head used for deferred freeing
  * @np:         OPP's device node.
  * @dentry:     debugfs dentry pointer (per opp)
  *
@@ -73,6 +70,7 @@ extern struct list_head opp_tables;
  */
 struct dev_pm_opp {
         struct list_head node;
+        struct kref kref;
 
         bool available;
         bool dynamic;
@@ -85,7 +83,6 @@ struct dev_pm_opp {
         unsigned long clock_latency_ns;
 
         struct opp_table *opp_table;
-        struct rcu_head rcu_head;
 
         struct device_node *np;
 
@@ -98,7 +95,6 @@ struct dev_pm_opp {
  * struct opp_device - devices managed by 'struct opp_table'
  * @node:       list node
  * @dev:        device to which the struct object belongs
- * @rcu_head:   RCU callback head used for deferred freeing
  * @dentry:     debugfs dentry pointer (per device)
  *
  * This is an internal data structure maintaining the devices that are managed
@@ -107,7 +103,6 @@ struct dev_pm_opp {
 struct opp_device {
         struct list_head node;
         const struct device *dev;
-        struct rcu_head rcu_head;
 
 #ifdef CONFIG_DEBUG_FS
         struct dentry *dentry;
@@ -125,12 +120,11 @@ enum opp_table_access {
  * @node:       table node - contains the devices with OPPs that
  *              have been registered. Nodes once added are not modified in this
  *              table.
- *              RCU usage: nodes are not modified in the table of opp_table,
- *              however addition is possible and is secured by opp_table_lock
- * @srcu_head:  notifier head to notify the OPP availability changes.
- * @rcu_head:   RCU callback head used for deferred freeing
+ * @head:       notifier head to notify the OPP availability changes.
  * @dev_list:   list of devices that share these OPPs
  * @opp_list:   table of opps
+ * @kref:       for reference count of the table.
+ * @lock:       mutex protecting the opp_list.
  * @np:         struct device_node pointer for opp's DT node.
  * @clock_latency_ns_max: Max clock latency in nanoseconds.
  * @shared_opp: OPP is shared between multiple devices.
@@ -151,18 +145,15 @@ enum opp_table_access {
  * This is an internal data structure maintaining the link to opps attached to
  * a device. This structure is not meant to be shared to users as it is
  * meant for book keeping and private to OPP library.
- *
- * Because the opp structures can be used from both rcu and srcu readers, we
- * need to wait for the grace period of both of them before freeing any
- * resources. And so we have used kfree_rcu() from within call_srcu() handlers.
  */
 struct opp_table {
         struct list_head node;
 
-        struct srcu_notifier_head srcu_head;
-        struct rcu_head rcu_head;
+        struct blocking_notifier_head head;
         struct list_head dev_list;
         struct list_head opp_list;
+        struct kref kref;
+        struct mutex lock;
 
         struct device_node *np;
         unsigned long clock_latency_ns_max;
@@ -190,14 +181,17 @@ struct opp_table {
 };
 
 /* Routines internal to opp core */
+void _get_opp_table_kref(struct opp_table *opp_table);
 struct opp_table *_find_opp_table(struct device *dev);
 struct opp_device *_add_opp_dev(const struct device *dev, struct opp_table *opp_table);
-void _dev_pm_opp_remove_table(struct device *dev, bool remove_all);
-struct dev_pm_opp *_allocate_opp(struct device *dev, struct opp_table **opp_table);
+void _dev_pm_opp_remove_table(struct opp_table *opp_table, struct device *dev, bool remove_all);
+void _dev_pm_opp_find_and_remove_table(struct device *dev, bool remove_all);
+struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table);
+void _opp_free(struct dev_pm_opp *opp);
 int _opp_add(struct device *dev, struct dev_pm_opp *new_opp, struct opp_table *opp_table);
-void _opp_remove(struct opp_table *opp_table, struct dev_pm_opp *opp, bool notify);
-int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt, bool dynamic);
+int _opp_add_v1(struct opp_table *opp_table, struct device *dev, unsigned long freq, long u_volt, bool dynamic);
 void _dev_pm_opp_cpumask_remove_table(const struct cpumask *cpumask, bool of);
+struct opp_table *_add_opp_table(struct device *dev);
 
 #ifdef CONFIG_OF
 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev);