Merge branch 'opp/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm

Pull operating performance points (OPP) framework changes for v4.21
from Viresh Kumar.

* 'opp/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
  OPP: Remove of_dev_pm_opp_find_required_opp()
  OPP: Rename and relocate of_genpd_opp_to_performance_state()
  OPP: Configure all required OPPs
  OPP: Add dev_pm_opp_{set|put}_genpd_virt_dev() helper
  PM / Domains: Add genpd_opp_to_performance_state()
  OPP: Populate OPPs from "required-opps" property
  OPP: Populate required opp tables from "required-opps" property
  OPP: Separate out custom OPP handler specific code
  OPP: Identify and mark genpd OPP tables
  PM / Domains: Rename genpd virtual devices as virt_dev

6 files changed, 526 insertions, 162 deletions

diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c
index 7f38a92b444a..8e554e6a82a2 100644
--- a/drivers/base/power/domain.c
+++ b/drivers/base/power/domain.c
@@ -2338,7 +2338,7 @@ EXPORT_SYMBOL_GPL(genpd_dev_pm_attach);
 struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 					 unsigned int index)
 {
-	struct device *genpd_dev;
+	struct device *virt_dev;
 	int num_domains;
 	int ret;
 
@@ -2352,31 +2352,31 @@ struct device *genpd_dev_pm_attach_by_id(struct device *dev,
 		return NULL;
 
 	/* Allocate and register device on the genpd bus. */
-	genpd_dev = kzalloc(sizeof(*genpd_dev), GFP_KERNEL);
-	if (!genpd_dev)
+	virt_dev = kzalloc(sizeof(*virt_dev), GFP_KERNEL);
+	if (!virt_dev)
 		return ERR_PTR(-ENOMEM);
 
-	dev_set_name(genpd_dev, "genpd:%u:%s", index, dev_name(dev));
-	genpd_dev->bus = &genpd_bus_type;
-	genpd_dev->release = genpd_release_dev;
+	dev_set_name(virt_dev, "genpd:%u:%s", index, dev_name(dev));
+	virt_dev->bus = &genpd_bus_type;
+	virt_dev->release = genpd_release_dev;
 
-	ret = device_register(genpd_dev);
+	ret = device_register(virt_dev);
 	if (ret) {
-		kfree(genpd_dev);
+		kfree(virt_dev);
 		return ERR_PTR(ret);
 	}
 
 	/* Try to attach the device to the PM domain at the specified index. */
-	ret = __genpd_dev_pm_attach(genpd_dev, dev->of_node, index, false);
+	ret = __genpd_dev_pm_attach(virt_dev, dev->of_node, index, false);
 	if (ret < 1) {
-		device_unregister(genpd_dev);
+		device_unregister(virt_dev);
 		return ret ? ERR_PTR(ret) : NULL;
 	}
 
-	pm_runtime_enable(genpd_dev);
-	genpd_queue_power_off_work(dev_to_genpd(genpd_dev));
+	pm_runtime_enable(virt_dev);
+	genpd_queue_power_off_work(dev_to_genpd(virt_dev));
 
-	return genpd_dev;
+	return virt_dev;
 }
 EXPORT_SYMBOL_GPL(genpd_dev_pm_attach_by_id);
 
@@ -2521,52 +2521,36 @@ int of_genpd_parse_idle_states(struct device_node *dn,
 EXPORT_SYMBOL_GPL(of_genpd_parse_idle_states);
 
 /**
- * of_genpd_opp_to_performance_state- Gets performance state of device's
- * power domain corresponding to a DT node's "required-opps" property.
+ * pm_genpd_opp_to_performance_state - Gets performance state of the genpd from its OPP node.
  *
- * @dev: Device for which the performance-state needs to be found.
- * @np: DT node where the "required-opps" property is present. This can be
- *	the device node itself (if it doesn't have an OPP table) or a node
- *	within the OPP table of a device (if device has an OPP table).
+ * @genpd_dev: Genpd's device for which the performance-state needs to be found.
+ * @opp: struct dev_pm_opp of the OPP for which we need to find performance
+ *	state.
  *
- * Returns performance state corresponding to the "required-opps" property of
- * a DT node. This calls platform specific genpd->opp_to_performance_state()
- * callback to translate power domain OPP to performance state.
+ * Returns performance state encoded in the OPP of the genpd. This calls
+ * platform specific genpd->opp_to_performance_state() callback to translate
+ * power domain OPP to performance state.
  *
  * Returns performance state on success and 0 on failure.
  */
-unsigned int of_genpd_opp_to_performance_state(struct device *dev,
-					       struct device_node *np)
+unsigned int pm_genpd_opp_to_performance_state(struct device *genpd_dev,
+					       struct dev_pm_opp *opp)
 {
-	struct generic_pm_domain *genpd;
-	struct dev_pm_opp *opp;
-	int state = 0;
+	struct generic_pm_domain *genpd = NULL;
+	int state;
 
-	genpd = dev_to_genpd(dev);
-	if (IS_ERR(genpd))
-		return 0;
+	genpd = container_of(genpd_dev, struct generic_pm_domain, dev);
 
-	if (unlikely(!genpd->set_performance_state))
+	if (unlikely(!genpd->opp_to_performance_state))
 		return 0;
 
 	genpd_lock(genpd);
-
-	opp = of_dev_pm_opp_find_required_opp(&genpd->dev, np);
-	if (IS_ERR(opp)) {
-		dev_err(dev, "Failed to find required OPP: %ld\n",
-			PTR_ERR(opp));
-		goto unlock;
-	}
-
 	state = genpd->opp_to_performance_state(genpd, opp);
-	dev_pm_opp_put(opp);
-
-unlock:
 	genpd_unlock(genpd);
 
 	return state;
 }
-EXPORT_SYMBOL_GPL(of_genpd_opp_to_performance_state);
+EXPORT_SYMBOL_GPL(pm_genpd_opp_to_performance_state);
 
 static int __init genpd_bus_init(void)
 {
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2c2df4e4fc14..0eaa954b3f6c 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -548,44 +548,6 @@ _generic_set_opp_clk_only(struct device *dev, struct clk *clk,
 	return ret;
 }
 
-static inline int
-_generic_set_opp_domain(struct device *dev, struct clk *clk,
-			unsigned long old_freq, unsigned long freq,
-			unsigned int old_pstate, unsigned int new_pstate)
-{
-	int ret;
-
-	/* Scaling up? Scale domain performance state before frequency */
-	if (freq > old_freq) {
-		ret = dev_pm_genpd_set_performance_state(dev, new_pstate);
-		if (ret)
-			return ret;
-	}
-
-	ret = _generic_set_opp_clk_only(dev, clk, old_freq, freq);
-	if (ret)
-		goto restore_domain_state;
-
-	/* Scaling down? Scale domain performance state after frequency */
-	if (freq < old_freq) {
-		ret = dev_pm_genpd_set_performance_state(dev, new_pstate);
-		if (ret)
-			goto restore_freq;
-	}
-
-	return 0;
-
-restore_freq:
-	if (_generic_set_opp_clk_only(dev, clk, freq, old_freq))
-		dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
-			__func__, old_freq);
-restore_domain_state:
-	if (freq > old_freq)
-		dev_pm_genpd_set_performance_state(dev, old_pstate);
-
-	return ret;
-}
-
 static int _generic_set_opp_regulator(const struct opp_table *opp_table,
 				      struct device *dev,
 				      unsigned long old_freq,
@@ -635,6 +597,84 @@ restore_voltage:
 	return ret;
 }
 
+static int _set_opp_custom(const struct opp_table *opp_table,
+			   struct device *dev, unsigned long old_freq,
+			   unsigned long freq,
+			   struct dev_pm_opp_supply *old_supply,
+			   struct dev_pm_opp_supply *new_supply)
+{
+	struct dev_pm_set_opp_data *data;
+	int size;
+
+	data = opp_table->set_opp_data;
+	data->regulators = opp_table->regulators;
+	data->regulator_count = opp_table->regulator_count;
+	data->clk = opp_table->clk;
+	data->dev = dev;
+
+	data->old_opp.rate = old_freq;
+	size = sizeof(*old_supply) * opp_table->regulator_count;
+	if (IS_ERR(old_supply))
+		memset(data->old_opp.supplies, 0, size);
+	else
+		memcpy(data->old_opp.supplies, old_supply, size);
+
+	data->new_opp.rate = freq;
+	memcpy(data->new_opp.supplies, new_supply, size);
+
+	return opp_table->set_opp(data);
+}
+
+/* This is only called for PM domain for now */
+static int _set_required_opps(struct device *dev,
+			      struct opp_table *opp_table,
+			      struct dev_pm_opp *opp)
+{
+	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
+	struct device **genpd_virt_devs = opp_table->genpd_virt_devs;
+	unsigned int pstate;
+	int i, ret = 0;
+
+	if (!required_opp_tables)
+		return 0;
+
+	/* Single genpd case */
+	if (!genpd_virt_devs) {
+		pstate = opp->required_opps[0]->pstate;
+		ret = dev_pm_genpd_set_performance_state(dev, pstate);
+		if (ret) {
+			dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
+				dev_name(dev), pstate, ret);
+		}
+		return ret;
+	}
+
+	/* Multiple genpd case */
+
+	/*
+	 * Acquire genpd_virt_dev_lock to make sure we don't use a genpd_dev
+	 * after it is freed from another thread.
+	 */
+	mutex_lock(&opp_table->genpd_virt_dev_lock);
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		pstate = opp->required_opps[i]->pstate;
+
+		if (!genpd_virt_devs[i])
+			continue;
+
+		ret = dev_pm_genpd_set_performance_state(genpd_virt_devs[i], pstate);
+		if (ret) {
+			dev_err(dev, "Failed to set performance rate of %s: %d (%d)\n",
+				dev_name(genpd_virt_devs[i]), pstate, ret);
+			break;
+		}
+	}
+	mutex_unlock(&opp_table->genpd_virt_dev_lock);
+
+	return ret;
+}
+
 /**
  * dev_pm_opp_set_rate() - Configure new OPP based on frequency
  * @dev:	 device for which we do this operation
@@ -649,7 +689,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	unsigned long freq, old_freq;
 	struct dev_pm_opp *old_opp, *opp;
 	struct clk *clk;
-	int ret, size;
+	int ret;
 
 	if (unlikely(!target_freq)) {
 		dev_err(dev, "%s: Invalid target frequency %lu\n", __func__,
@@ -702,44 +742,34 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 	dev_dbg(dev, "%s: switching OPP: %lu Hz --> %lu Hz\n", __func__,
 		old_freq, freq);
 
-	/* Only frequency scaling */
-	if (!opp_table->regulators) {
-		/*
-		 * We don't support devices with both regulator and
-		 * domain performance-state for now.
-		 */
-		if (opp_table->genpd_performance_state)
-			ret = _generic_set_opp_domain(dev, clk, old_freq, freq,
-						      IS_ERR(old_opp) ? 0 : old_opp->pstate,
-						      opp->pstate);
-		else
-			ret = _generic_set_opp_clk_only(dev, clk, old_freq, freq);
-	} else if (!opp_table->set_opp) {
+	/* Scaling up? Configure required OPPs before frequency */
+	if (freq > old_freq) {
+		ret = _set_required_opps(dev, opp_table, opp);
+		if (ret)
+			goto put_opp;
+	}
+
+	if (opp_table->set_opp) {
+		ret = _set_opp_custom(opp_table, dev, old_freq, freq,
+				      IS_ERR(old_opp) ? NULL : old_opp->supplies,
+				      opp->supplies);
+	} else if (opp_table->regulators) {
 		ret = _generic_set_opp_regulator(opp_table, dev, old_freq, freq,
 						 IS_ERR(old_opp) ? NULL : old_opp->supplies,
 						 opp->supplies);
 	} else {
-		struct dev_pm_set_opp_data *data;
-
-		data = opp_table->set_opp_data;
-		data->regulators = opp_table->regulators;
-		data->regulator_count = opp_table->regulator_count;
-		data->clk = clk;
-		data->dev = dev;
-
-		data->old_opp.rate = old_freq;
-		size = sizeof(*opp->supplies) * opp_table->regulator_count;
-		if (IS_ERR(old_opp))
-			memset(data->old_opp.supplies, 0, size);
-		else
-			memcpy(data->old_opp.supplies, old_opp->supplies, size);
-
-		data->new_opp.rate = freq;
-		memcpy(data->new_opp.supplies, opp->supplies, size);
+		/* Only frequency scaling */
+		ret = _generic_set_opp_clk_only(dev, clk, old_freq, freq);
+	}
 
-		ret = opp_table->set_opp(data);
+	/* Scaling down? Configure required OPPs after frequency */
+	if (!ret && freq < old_freq) {
+		ret = _set_required_opps(dev, opp_table, opp);
+		if (ret)
+			dev_err(dev, "Failed to set required opps: %d\n", ret);
 	}
 
+put_opp:
 	dev_pm_opp_put(opp);
 put_old_opp:
 	if (!IS_ERR(old_opp))
@@ -810,6 +840,7 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
 		return NULL;
 
 	mutex_init(&opp_table->lock);
+	mutex_init(&opp_table->genpd_virt_dev_lock);
 	INIT_LIST_HEAD(&opp_table->dev_list);
 
 	opp_dev = _add_opp_dev(dev, opp_table);
@@ -888,6 +919,8 @@ 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, *temp;
 
+	_of_clear_opp_table(opp_table);
+
 	/* Release clk */
 	if (!IS_ERR(opp_table->clk))
 		clk_put(opp_table->clk);
@@ -905,6 +938,7 @@ static void _opp_table_kref_release(struct kref *kref)
 		_remove_opp_dev(opp_dev, opp_table);
 	}
 
+	mutex_destroy(&opp_table->genpd_virt_dev_lock);
 	mutex_destroy(&opp_table->lock);
 	list_del(&opp_table->node);
 	kfree(opp_table);
@@ -961,6 +995,7 @@ static void _opp_kref_release(struct kref *kref)
 	 * frequency/voltage list.
 	 */
 	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_REMOVE, opp);
+	_of_opp_free_required_opps(opp_table, opp);
 	opp_debug_remove_one(opp);
 	list_del(&opp->node);
 	kfree(opp);
@@ -1587,6 +1622,92 @@ void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table)
 EXPORT_SYMBOL_GPL(dev_pm_opp_unregister_set_opp_helper);
 
 /**
+ * dev_pm_opp_set_genpd_virt_dev - Set virtual genpd device for an index
+ * @dev: Consumer device for which the genpd device is getting set.
+ * @virt_dev: virtual genpd device.
+ * @index: index.
+ *
+ * Multiple generic power domains for a device are supported with the help of
+ * virtual genpd devices, which are created for each consumer device - genpd
+ * pair. These are the device structures which are attached to the power domain
+ * and are required by the OPP core to set the performance state of the genpd.
+ *
+ * This helper will normally be called by the consumer driver of the device
+ * "dev", as only that has details of the genpd devices.
+ *
+ * This helper needs to be called once for each of those virtual devices, but
+ * only if multiple domains are available for a device. Otherwise the original
+ * device structure will be used instead by the OPP core.
+ */
+struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev,
+						struct device *virt_dev,
+						int index)
+{
+	struct opp_table *opp_table;
+
+	opp_table = dev_pm_opp_get_opp_table(dev);
+	if (!opp_table)
+		return ERR_PTR(-ENOMEM);
+
+	mutex_lock(&opp_table->genpd_virt_dev_lock);
+
+	if (unlikely(!opp_table->genpd_virt_devs ||
+		     index >= opp_table->required_opp_count ||
+		     opp_table->genpd_virt_devs[index])) {
+
+		dev_err(dev, "Invalid request to set required device\n");
+		dev_pm_opp_put_opp_table(opp_table);
+		mutex_unlock(&opp_table->genpd_virt_dev_lock);
+
+		return ERR_PTR(-EINVAL);
+	}
+
+	opp_table->genpd_virt_devs[index] = virt_dev;
+	mutex_unlock(&opp_table->genpd_virt_dev_lock);
+
+	return opp_table;
+}
+
+/**
+ * dev_pm_opp_put_genpd_virt_dev() - Releases resources blocked for genpd device.
+ * @opp_table: OPP table returned by dev_pm_opp_set_genpd_virt_dev().
+ * @virt_dev: virtual genpd device.
+ *
+ * This releases the resource previously acquired with a call to
+ * dev_pm_opp_set_genpd_virt_dev(). The consumer driver shall call this helper
+ * if it doesn't want OPP core to update performance state of a power domain
+ * anymore.
+ */
+void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table,
+				   struct device *virt_dev)
+{
+	int i;
+
+	/*
+	 * Acquire genpd_virt_dev_lock to make sure virt_dev isn't getting
+	 * used in parallel.
+	 */
+	mutex_lock(&opp_table->genpd_virt_dev_lock);
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		if (opp_table->genpd_virt_devs[i] != virt_dev)
+			continue;
+
+		opp_table->genpd_virt_devs[i] = NULL;
+		dev_pm_opp_put_opp_table(opp_table);
+
+		/* Drop the vote */
+		dev_pm_genpd_set_performance_state(virt_dev, 0);
+		break;
+	}
+
+	mutex_unlock(&opp_table->genpd_virt_dev_lock);
+
+	if (unlikely(i == opp_table->required_opp_count))
+		dev_err(virt_dev, "Failed to find required device entry\n");
+}
+
+/**
  * dev_pm_opp_add()  - Add an OPP table from a table definitions
  * @dev:	device for which we do this operation
  * @freq:	Frequency in Hz for this OPP
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 38a08805a30c..840f85181a37 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -73,6 +73,161 @@ struct opp_table *_managed_opp(struct device *dev, int index)
 	return managed_table;
 }
 
+/* The caller must call dev_pm_opp_put() after the OPP is used */
+static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
+					  struct device_node *opp_np)
+{
+	struct dev_pm_opp *opp;
+
+	lockdep_assert_held(&opp_table_lock);
+
+	mutex_lock(&opp_table->lock);
+
+	list_for_each_entry(opp, &opp_table->opp_list, node) {
+		if (opp->np == opp_np) {
+			dev_pm_opp_get(opp);
+			mutex_unlock(&opp_table->lock);
+			return opp;
+		}
+	}
+
+	mutex_unlock(&opp_table->lock);
+
+	return NULL;
+}
+
+static struct device_node *of_parse_required_opp(struct device_node *np,
+						 int index)
+{
+	struct device_node *required_np;
+
+	required_np = of_parse_phandle(np, "required-opps", index);
+	if (unlikely(!required_np)) {
+		pr_err("%s: Unable to parse required-opps: %pOF, index: %d\n",
+		       __func__, np, index);
+	}
+
+	return required_np;
+}
+
+/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
+static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
+{
+	struct opp_table *opp_table;
+	struct dev_pm_opp *opp;
+
+	lockdep_assert_held(&opp_table_lock);
+
+	list_for_each_entry(opp_table, &opp_tables, node) {
+		opp = _find_opp_of_np(opp_table, opp_np);
+		if (opp) {
+			dev_pm_opp_put(opp);
+			_get_opp_table_kref(opp_table);
+			return opp_table;
+		}
+	}
+
+	return ERR_PTR(-ENODEV);
+}
+
+/* Free resources previously acquired by _opp_table_alloc_required_tables() */
+static void _opp_table_free_required_tables(struct opp_table *opp_table)
+{
+	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
+	struct device **genpd_virt_devs = opp_table->genpd_virt_devs;
+	int i;
+
+	if (!required_opp_tables)
+		return;
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		if (IS_ERR_OR_NULL(required_opp_tables[i]))
+			break;
+
+		dev_pm_opp_put_opp_table(required_opp_tables[i]);
+	}
+
+	kfree(required_opp_tables);
+	kfree(genpd_virt_devs);
+
+	opp_table->required_opp_count = 0;
+	opp_table->genpd_virt_devs = NULL;
+	opp_table->required_opp_tables = NULL;
+}
+
+/*
+ * Populate all devices and opp tables which are part of "required-opps" list.
+ * Checking only the first OPP node should be enough.
+ */
+static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
+					     struct device *dev,
+					     struct device_node *opp_np)
+{
+	struct opp_table **required_opp_tables;
+	struct device **genpd_virt_devs = NULL;
+	struct device_node *required_np, *np;
+	int count, i;
+
+	/* Traversing the first OPP node is all we need */
+	np = of_get_next_available_child(opp_np, NULL);
+	if (!np) {
+		dev_err(dev, "Empty OPP table\n");
+		return;
+	}
+
+	count = of_count_phandle_with_args(np, "required-opps", NULL);
+	if (!count)
+		goto put_np;
+
+	if (count > 1) {
+		genpd_virt_devs = kcalloc(count, sizeof(*genpd_virt_devs),
+					GFP_KERNEL);
+		if (!genpd_virt_devs)
+			goto put_np;
+	}
+
+	required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
+				      GFP_KERNEL);
+	if (!required_opp_tables) {
+		kfree(genpd_virt_devs);
+		goto put_np;
+	}
+
+	opp_table->genpd_virt_devs = genpd_virt_devs;
+	opp_table->required_opp_tables = required_opp_tables;
+	opp_table->required_opp_count = count;
+
+	for (i = 0; i < count; i++) {
+		required_np = of_parse_required_opp(np, i);
+		if (!required_np)
+			goto free_required_tables;
+
+		required_opp_tables[i] = _find_table_of_opp_np(required_np);
+		of_node_put(required_np);
+
+		if (IS_ERR(required_opp_tables[i]))
+			goto free_required_tables;
+
+		/*
+		 * We only support genpd's OPPs in the "required-opps" for now,
+		 * as we don't know how much about other cases. Error out if the
+		 * required OPP doesn't belong to a genpd.
+		 */
+		if (!required_opp_tables[i]->is_genpd) {
+			dev_err(dev, "required-opp doesn't belong to genpd: %pOF\n",
+				required_np);
+			goto free_required_tables;
+		}
+	}
+
+	goto put_np;
+
+free_required_tables:
+	_opp_table_free_required_tables(opp_table);
+put_np:
+	of_node_put(np);
+}
+
 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
 			int index)
 {
@@ -92,6 +247,9 @@ void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
 	of_property_read_u32(np, "voltage-tolerance",
 			     &opp_table->voltage_tolerance_v1);
 
+	if (of_find_property(np, "#power-domain-cells", NULL))
+		opp_table->is_genpd = true;
+
 	/* Get OPP table node */
 	opp_np = _opp_of_get_opp_desc_node(np, index);
 	of_node_put(np);
@@ -106,9 +264,86 @@ void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
 
 	opp_table->np = opp_np;
 
+	_opp_table_alloc_required_tables(opp_table, dev, opp_np);
 	of_node_put(opp_np);
 }
 
+void _of_clear_opp_table(struct opp_table *opp_table)
+{
+	_opp_table_free_required_tables(opp_table);
+}
+
+/*
+ * Release all resources previously acquired with a call to
+ * _of_opp_alloc_required_opps().
+ */
+void _of_opp_free_required_opps(struct opp_table *opp_table,
+				struct dev_pm_opp *opp)
+{
+	struct dev_pm_opp **required_opps = opp->required_opps;
+	int i;
+
+	if (!required_opps)
+		return;
+
+	for (i = 0; i < opp_table->required_opp_count; i++) {
+		if (!required_opps[i])
+			break;
+
+		/* Put the reference back */
+		dev_pm_opp_put(required_opps[i]);
+	}
+
+	kfree(required_opps);
+	opp->required_opps = NULL;
+}
+
+/* Populate all required OPPs which are part of "required-opps" list */
+static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
+				       struct dev_pm_opp *opp)
+{
+	struct dev_pm_opp **required_opps;
+	struct opp_table *required_table;
+	struct device_node *np;
+	int i, ret, count = opp_table->required_opp_count;
+
+	if (!count)
+		return 0;
+
+	required_opps = kcalloc(count, sizeof(*required_opps), GFP_KERNEL);
+	if (!required_opps)
+		return -ENOMEM;
+
+	opp->required_opps = required_opps;
+
+	for (i = 0; i < count; i++) {
+		required_table = opp_table->required_opp_tables[i];
+
+		np = of_parse_required_opp(opp->np, i);
+		if (unlikely(!np)) {
+			ret = -ENODEV;
+			goto free_required_opps;
+		}
+
+		required_opps[i] = _find_opp_of_np(required_table, np);
+		of_node_put(np);
+
+		if (!required_opps[i]) {
+			pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
+			       __func__, opp->np, i);
+			ret = -ENODEV;
+			goto free_required_opps;
+		}
+	}
+
+	return 0;
+
+free_required_opps:
+	_of_opp_free_required_opps(opp_table, opp);
+
+	return ret;
+}
+
 static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
 			      struct device_node *np)
 {
@@ -326,8 +561,7 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	ret = of_property_read_u64(np, "opp-hz", &rate);
 	if (ret < 0) {
 		/* "opp-hz" is optional for devices like power domains. */
-		if (!of_find_property(dev->of_node, "#power-domain-cells",
-				      NULL)) {
+		if (!opp_table->is_genpd) {
 			dev_err(dev, "%s: opp-hz not found\n", __func__);
 			goto free_opp;
 		}
@@ -354,21 +588,26 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	new_opp->dynamic = false;
 	new_opp->available = true;
 
+	ret = _of_opp_alloc_required_opps(opp_table, new_opp);
+	if (ret)
+		goto free_opp;
+
 	if (!of_property_read_u32(np, "clock-latency-ns", &val))
 		new_opp->clock_latency_ns = val;
 
-	new_opp->pstate = of_genpd_opp_to_performance_state(dev, np);
-
 	ret = opp_parse_supplies(new_opp, dev, opp_table);
 	if (ret)
-		goto free_opp;
+		goto free_required_opps;
+
+	if (opp_table->is_genpd)
+		new_opp->pstate = pm_genpd_opp_to_performance_state(dev, new_opp);
 
 	ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
 	if (ret) {
 		/* Don't return error for duplicate OPPs */
 		if (ret == -EBUSY)
 			ret = 0;
-		goto free_opp;
+		goto free_required_opps;
 	}
 
 	/* OPP to select on device suspend */
@@ -398,6 +637,8 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
 	return new_opp;
 
+free_required_opps:
+	_of_opp_free_required_opps(opp_table, new_opp);
 free_opp:
 	_opp_free(new_opp);
 
@@ -727,58 +968,48 @@ put_cpu_node:
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
 
 /**
- * of_dev_pm_opp_find_required_opp() - Search for required OPP.
- * @dev: The device whose OPP node is referenced by the 'np' DT node.
+ * of_get_required_opp_performance_state() - Search for required OPP and return its performance state.
  * @np: Node that contains the "required-opps" property.
+ * @index: Index of the phandle to parse.
  *
- * Returns the OPP of the device 'dev', whose phandle is present in the "np"
- * node. Although the "required-opps" property supports having multiple
- * phandles, this helper routine only parses the very first phandle in the list.
- *
- * Return: Matching opp, else returns ERR_PTR in case of error and should be
- * handled using IS_ERR.
+ * Returns the performance state of the OPP pointed out by the "required-opps"
+ * property at @index in @np.
  *
- * The callers are required to call dev_pm_opp_put() for the returned OPP after
- * use.
+ * Return: Positive performance state on success, otherwise 0 on errors.
  */
-struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
-						   struct device_node *np)
+unsigned int of_get_required_opp_performance_state(struct device_node *np,
+						   int index)
 {
-	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
+	struct dev_pm_opp *opp;
 	struct device_node *required_np;
 	struct opp_table *opp_table;
+	unsigned int pstate = 0;
 
-	opp_table = _find_opp_table(dev);
-	if (IS_ERR(opp_table))
-		return ERR_CAST(opp_table);
+	required_np = of_parse_required_opp(np, index);
+	if (!required_np)
+		return 0;
 
-	required_np = of_parse_phandle(np, "required-opps", 0);
-	if (unlikely(!required_np)) {
-		dev_err(dev, "Unable to parse required-opps\n");
-		goto put_opp_table;
+	opp_table = _find_table_of_opp_np(required_np);
+	if (IS_ERR(opp_table)) {
+		pr_err("%s: Failed to find required OPP table %pOF: %ld\n",
+		       __func__, np, PTR_ERR(opp_table));
+		goto put_required_np;
 	}
 
-	mutex_lock(&opp_table->lock);
-
-	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
-		if (temp_opp->available && temp_opp->np == required_np) {
-			opp = temp_opp;
-
-			/* Increment the reference count of OPP */
-			dev_pm_opp_get(opp);
-			break;
-		}
+	opp = _find_opp_of_np(opp_table, required_np);
+	if (opp) {
+		pstate = opp->pstate;
+		dev_pm_opp_put(opp);
 	}
 
-	mutex_unlock(&opp_table->lock);
+	dev_pm_opp_put_opp_table(opp_table);
 
+put_required_np:
 	of_node_put(required_np);
-put_opp_table:
-	dev_pm_opp_put_opp_table(opp_table);
 
-	return opp;
+	return pstate;
 }
-EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);
+EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);
 
 /**
  * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 9c6544b4f4f9..8aec38792cae 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -63,6 +63,7 @@ extern struct list_head opp_tables;
  * @supplies:	Power supplies voltage/current values
  * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
  *		frequency from any other OPP's frequency.
+ * @required_opps: List of OPPs that are required by this OPP.
  * @opp_table:	points back to the opp_table struct this opp belongs to
  * @np:		OPP's device node.
  * @dentry:	debugfs dentry pointer (per opp)
@@ -84,6 +85,7 @@ struct dev_pm_opp {
 
 	unsigned long clock_latency_ns;
 
+	struct dev_pm_opp **required_opps;
 	struct opp_table *opp_table;
 
 	struct device_node *np;
@@ -133,6 +135,11 @@ enum opp_table_access {
  * @parsed_static_opps: True if OPPs are initialized from DT.
  * @shared_opp: OPP is shared between multiple devices.
  * @suspend_opp: Pointer to OPP to be used during device suspend.
+ * @genpd_virt_dev_lock: Mutex protecting the genpd virtual device pointers.
+ * @genpd_virt_devs: List of virtual devices for multiple genpd support.
+ * @required_opp_tables: List of device OPP tables that are required by OPPs in
+ *		this table.
+ * @required_opp_count: Number of required devices.
  * @supported_hw: Array of version number to support.
  * @supported_hw_count: Number of elements in supported_hw array.
  * @prop_name: A name to postfix to many DT properties, while parsing them.
@@ -140,6 +147,7 @@ enum opp_table_access {
  * @regulators: Supply regulators
  * @regulator_count: Number of power supply regulators
  * @genpd_performance_state: Device's power domain support performance state.
+ * @is_genpd: Marks if the OPP table belongs to a genpd.
  * @set_opp: Platform specific set_opp callback
  * @set_opp_data: Data to be passed to set_opp callback
  * @dentry:	debugfs dentry pointer of the real device directory (not links).
@@ -171,6 +179,11 @@ struct opp_table {
 	enum opp_table_access shared_opp;
 	struct dev_pm_opp *suspend_opp;
 
+	struct mutex genpd_virt_dev_lock;
+	struct device **genpd_virt_devs;
+	struct opp_table **required_opp_tables;
+	unsigned int required_opp_count;
+
 	unsigned int *supported_hw;
 	unsigned int supported_hw_count;
 	const char *prop_name;
@@ -178,6 +191,7 @@ struct opp_table {
 	struct regulator **regulators;
 	unsigned int regulator_count;
 	bool genpd_performance_state;
+	bool is_genpd;
 
 	int (*set_opp)(struct dev_pm_set_opp_data *data);
 	struct dev_pm_set_opp_data *set_opp_data;
@@ -206,10 +220,16 @@ void _put_opp_list_kref(struct opp_table *opp_table);
 
 #ifdef CONFIG_OF
 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev, int index);
+void _of_clear_opp_table(struct opp_table *opp_table);
 struct opp_table *_managed_opp(struct device *dev, int index);
+void _of_opp_free_required_opps(struct opp_table *opp_table,
+				struct dev_pm_opp *opp);
 #else
 static inline void _of_init_opp_table(struct opp_table *opp_table, struct device *dev, int index) {}
+static inline void _of_clear_opp_table(struct opp_table *opp_table) {}
 static inline struct opp_table *_managed_opp(struct device *dev, int index) { return NULL; }
+static inline void _of_opp_free_required_opps(struct opp_table *opp_table,
+					      struct dev_pm_opp *opp) {}
 #endif
 
 #ifdef CONFIG_DEBUG_FS
diff --git a/include/linux/pm_domain.h b/include/linux/pm_domain.h
index 3b5d7280e52e..642036952553 100644
--- a/include/linux/pm_domain.h
+++ b/include/linux/pm_domain.h
@@ -258,8 +258,8 @@ int of_genpd_add_subdomain(struct of_phandle_args *parent,
 struct generic_pm_domain *of_genpd_remove_last(struct device_node *np);
 int of_genpd_parse_idle_states(struct device_node *dn,
 			       struct genpd_power_state **states, int *n);
-unsigned int of_genpd_opp_to_performance_state(struct device *dev,
-				struct device_node *np);
+unsigned int pm_genpd_opp_to_performance_state(struct device *genpd_dev,
+					       struct dev_pm_opp *opp);
 
 int genpd_dev_pm_attach(struct device *dev);
 struct device *genpd_dev_pm_attach_by_id(struct device *dev,
@@ -300,8 +300,8 @@ static inline int of_genpd_parse_idle_states(struct device_node *dn,
 }
 
 static inline unsigned int
-of_genpd_opp_to_performance_state(struct device *dev,
-				  struct device_node *np)
+pm_genpd_opp_to_performance_state(struct device *genpd_dev,
+				  struct dev_pm_opp *opp)
 {
 	return 0;
 }
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 5d399eeef172..2b2c3fd985ab 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -126,6 +126,8 @@ struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const char * name);
 void dev_pm_opp_put_clkname(struct opp_table *opp_table);
 struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev, int (*set_opp)(struct dev_pm_set_opp_data *data));
 void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table);
+struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev, struct device *virt_dev, int index);
+void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table, struct device *virt_dev);
 int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq);
 int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev, const struct cpumask *cpumask);
 int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);
@@ -272,6 +274,12 @@ static inline struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const
 
 static inline void dev_pm_opp_put_clkname(struct opp_table *opp_table) {}
 
+static inline struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev, struct device *virt_dev, int index)
+{
+	return ERR_PTR(-ENOTSUPP);
+}
+
+static inline void dev_pm_opp_put_genpd_virt_dev(struct opp_table *opp_table, struct device *virt_dev) {}
 static inline int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
 {
 	return -ENOTSUPP;
@@ -305,8 +313,8 @@ int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask);
 void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask);
 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, struct cpumask *cpumask);
 struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev);
-struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev, struct device_node *np);
 struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp);
+unsigned int of_get_required_opp_performance_state(struct device_node *np, int index);
 #else
 static inline int dev_pm_opp_of_add_table(struct device *dev)
 {
@@ -341,13 +349,13 @@ static inline struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device
 	return NULL;
 }
 
-static inline struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev, struct device_node *np)
+static inline struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
 {
 	return NULL;
 }
-static inline struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
+static inline unsigned int of_get_required_opp_performance_state(struct device_node *np, int index)
 {
-	return NULL;
+	return 0;
 }
 #endif