Merge tag 'pm-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "These add sysadmin documentation for cpuidle, extend the cpuidle
  subsystem somewhat, improve the handling of performance states in the
  generic power domains (genpd) and operating performance points (OPP)
  frameworks, add a new cpufreq driver for Qualcomm SoCs, update some
  other cpufreq drivers, switch over the runtime PM framework to using
  high-res timers for device autosuspend, fix a problem with
  suspend-to-idle on ACPI-based platforms, add system-wide suspend and
  resume handling to the devfreq framework, do some janitorial cleanups
  all over and update some utilities.

  Specifics:

   - Add sysadmin documentation for cpuidle (Rafael Wysocki).

   - Make it possible to specify a cpuidle governor from kernel command
     line, add new cpuidle state sysfs attributes for governor
     evaluation, and improve the "polling" idle state handling (Rafael
     Wysocki).

   - Fix the handling of the "required-opps" DT property in the
     operating performance points (OPP) framework, improve the
     integration of it with the generic power domains (genpd) framework,
     improve the handling of performance states in them and clean up the
     idle states vs performance states separation in genpd (Viresh
     Kumar, Ulf Hansson).

   - Add a cpufreq driver called "qcom-hw" for Qualcomm SoCs using a
     hardware engine to control CPU frequency transitions along with DT
     bindings for it (Taniya Das).

   - Fix an intel_pstate driver issue related to CPU offline and update
     the documentation of it (Srinivas Pandruvada).

   - Clean up the imx6q cpufreq driver (Anson Huang).

   - Add SPDX license IDs to cpufreq schedutil governor files (Daniel
     Lezcano).

   - Switch over the runtime PM framework to using high-res timers for
     device autosuspend to allow the control of it to be more precise
     (Vincent Guittot).

   - Disable non-wakeup ACPI GPEs during suspend-to-idle so that they
     don't prevent the system from reaching the target low-power state
     and simplify the suspend-to-idle handling on ACPI platforms without
     full Low-Power S0 Idle (LPS0) support (Rafael Wysocki).

   - Add system-wide suspend and resume support to the devfreq framework
     (Lukasz Luba).

   - Clean up the SmartReflex adaptive voltage scaling (AVS) driver and
     add an SPDX license ID to it (Nishanth Menon, Uwe Kleine-König,
     Thomas Meyer).

   - Get rid of code duplication by using the DEFINE_SHOW_ATTRIBUTE
     macro in some places, fix some DT node refcount leaks, and do some
     other janitorial cleanups (Yangtao Li).

   - Update the cpupower, intel_pstate_tracer and turbosat utilities
     (Abhishek Goel, Doug Smythies, Len Brown)"

* tag 'pm-4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (54 commits)
  PM / Domains: remove define_genpd_open_function() and define_genpd_debugfs_fops()
  PM-runtime: Switch autosuspend over to using hrtimers
  cpufreq: qcom-hw: Add support for QCOM cpufreq HW driver
  dt-bindings: cpufreq: Introduce QCOM cpufreq firmware bindings
  ACPI: PM: Loop in full LPS0 mode only
  ACPI: EC / PM: Disable non-wakeup GPEs for suspend-to-idle
  tools/power/x86/intel_pstate_tracer: Fix non root execution for post processing a trace file
  tools/power turbostat: consolidate duplicate model numbers
  tools/power turbostat: fix goldmont C-state limit decoding
  PM / Domains: Propagate performance state updates
  PM / Domains: Factorize dev_pm_genpd_set_performance_state()
  PM / Domains: Save OPP table pointer in genpd
  OPP: Don't return 0 on error from of_get_required_opp_performance_state()
  OPP: Add dev_pm_opp_xlate_performance_state() helper
  OPP: Improve _find_table_of_opp_np()
  PM / Domains: Make genpd performance states orthogonal to the idlestates
  PM / sleep: convert to DEFINE_SHOW_ATTRIBUTE
  cpuidle: Add 'above' and 'below' idle state metrics
  PM / AVS: SmartReflex: Switch to SPDX Licence ID
  PM / AVS: SmartReflex: NULL check before some freeing functions is not needed
  ...

3 files changed, 588 insertions, 124 deletions

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index 2c2df4e4fc14..e5507add8f04 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -196,12 +196,12 @@ unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
 	if (IS_ERR(opp_table))
 		return 0;
 
-	count = opp_table->regulator_count;
-
 	/* Regulator may not be required for the device */
-	if (!count)
+	if (!opp_table->regulators)
 		goto put_opp_table;
 
+	count = opp_table->regulator_count;
+
 	uV = kmalloc_array(count, sizeof(*uV), GFP_KERNEL);
 	if (!uV)
 		goto put_opp_table;
@@ -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))
@@ -810,8 +840,12 @@ 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);
 
+	/* Mark regulator count uninitialized */
+	opp_table->regulator_count = -1;
+
 	opp_dev = _add_opp_dev(dev, opp_table);
 	if (!opp_dev) {
 		kfree(opp_table);
@@ -888,6 +922,8 @@ 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 +941,7 @@ 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 +998,7 @@ 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);
@@ -1028,7 +1066,7 @@ struct dev_pm_opp *_opp_allocate(struct opp_table *table)
 	int count, supply_size;
 
 	/* Allocate space for at least one supply */
-	count = table->regulator_count ? table->regulator_count : 1;
+	count = table->regulator_count > 0 ? table->regulator_count : 1;
 	supply_size = sizeof(*opp->supplies) * count;
 
 	/* allocate new OPP node and supplies structures */
@@ -1049,6 +1087,9 @@ static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
 	struct regulator *reg;
 	int i;
 
+	if (!opp_table->regulators)
+		return true;
+
 	for (i = 0; i < opp_table->regulator_count; i++) {
 		reg = opp_table->regulators[i];
 
@@ -1333,7 +1374,7 @@ static int _allocate_set_opp_data(struct opp_table *opp_table)
 	struct dev_pm_set_opp_data *data;
 	int len, count = opp_table->regulator_count;
 
-	if (WARN_ON(!count))
+	if (WARN_ON(!opp_table->regulators))
 		return -EINVAL;
 
 	/* space for set_opp_data */
@@ -1430,7 +1471,7 @@ free_regulators:
 
 	kfree(opp_table->regulators);
 	opp_table->regulators = NULL;
-	opp_table->regulator_count = 0;
+	opp_table->regulator_count = -1;
 err:
 	dev_pm_opp_put_opp_table(opp_table);
 
@@ -1459,7 +1500,7 @@ void dev_pm_opp_put_regulators(struct opp_table *opp_table)
 
 	kfree(opp_table->regulators);
 	opp_table->regulators = NULL;
-	opp_table->regulator_count = 0;
+	opp_table->regulator_count = -1;
 
 put_opp_table:
 	dev_pm_opp_put_opp_table(opp_table);
@@ -1587,6 +1628,155 @@ 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_xlate_performance_state() - Find required OPP's pstate for src_table.
+ * @src_table: OPP table which has dst_table as one of its required OPP table.
+ * @dst_table: Required OPP table of the src_table.
+ * @pstate: Current performance state of the src_table.
+ *
+ * This Returns pstate of the OPP (present in @dst_table) pointed out by the
+ * "required-opps" property of the OPP (present in @src_table) which has
+ * performance state set to @pstate.
+ *
+ * Return: Zero or positive performance state on success, otherwise negative
+ * value on errors.
+ */
+int dev_pm_opp_xlate_performance_state(struct opp_table *src_table,
+				       struct opp_table *dst_table,
+				       unsigned int pstate)
+{
+	struct dev_pm_opp *opp;
+	int dest_pstate = -EINVAL;
+	int i;
+
+	if (!pstate)
+		return 0;
+
+	/*
+	 * Normally the src_table will have the "required_opps" property set to
+	 * point to one of the OPPs in the dst_table, but in some cases the
+	 * genpd and its master have one to one mapping of performance states
+	 * and so none of them have the "required-opps" property set. Return the
+	 * pstate of the src_table as it is in such cases.
+	 */
+	if (!src_table->required_opp_count)
+		return pstate;
+
+	for (i = 0; i < src_table->required_opp_count; i++) {
+		if (src_table->required_opp_tables[i]->np == dst_table->np)
+			break;
+	}
+
+	if (unlikely(i == src_table->required_opp_count)) {
+		pr_err("%s: Couldn't find matching OPP table (%p: %p)\n",
+		       __func__, src_table, dst_table);
+		return -EINVAL;
+	}
+
+	mutex_lock(&src_table->lock);
+
+	list_for_each_entry(opp, &src_table->opp_list, node) {
+		if (opp->pstate == pstate) {
+			dest_pstate = opp->required_opps[i]->pstate;
+			goto unlock;
+		}
+	}
+
+	pr_err("%s: Couldn't find matching OPP (%p: %p)\n", __func__, src_table,
+	       dst_table);
+
+unlock:
+	mutex_unlock(&src_table->lock);
+
+	return dest_pstate;
+}
+
+/**
  * 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
@@ -1612,6 +1802,9 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
 	if (!opp_table)
 		return -ENOMEM;
 
+	/* Fix regulator count for dynamic OPPs */
+	opp_table->regulator_count = 1;
+
 	ret = _opp_add_v1(opp_table, dev, freq, u_volt, true);
 	if (ret)
 		dev_pm_opp_put_opp_table(opp_table);
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 38a08805a30c..06f0f632ec47 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -73,6 +73,167 @@ 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 device_node *opp_table_np;
+
+	lockdep_assert_held(&opp_table_lock);
+
+	opp_table_np = of_get_parent(opp_np);
+	if (!opp_table_np)
+		goto err;
+
+	/* It is safe to put the node now as all we need now is its address */
+	of_node_put(opp_table_np);
+
+	list_for_each_entry(opp_table, &opp_tables, node) {
+		if (opp_table_np == opp_table->np) {
+			_get_opp_table_kref(opp_table);
+			return opp_table;
+		}
+	}
+
+err:
+	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 +253,9 @@ 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 +270,86 @@ 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)
 {
@@ -150,12 +391,10 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 			      struct opp_table *opp_table)
 {
 	u32 *microvolt, *microamp = NULL;
-	int supplies, vcount, icount, ret, i, j;
+	int supplies = opp_table->regulator_count, vcount, icount, ret, i, j;
 	struct property *prop = NULL;
 	char name[NAME_MAX];
 
-	supplies = opp_table->regulator_count ? opp_table->regulator_count : 1;
-
 	/* Search for "opp-microvolt-<name>" */
 	if (opp_table->prop_name) {
 		snprintf(name, sizeof(name), "opp-microvolt-%s",
@@ -170,7 +409,13 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 
 		/* Missing property isn't a problem, but an invalid entry is */
 		if (!prop) {
-			if (!opp_table->regulator_count)
+			if (unlikely(supplies == -1)) {
+				/* Initialize regulator_count */
+				opp_table->regulator_count = 0;
+				return 0;
+			}
+
+			if (!supplies)
 				return 0;
 
 			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
@@ -179,6 +424,14 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 		}
 	}
 
+	if (unlikely(supplies == -1)) {
+		/* Initialize regulator_count */
+		supplies = opp_table->regulator_count = 1;
+	} else if (unlikely(!supplies)) {
+		dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
+		return -EINVAL;
+	}
+
 	vcount = of_property_count_u32_elems(opp->np, name);
 	if (vcount < 0) {
 		dev_err(dev, "%s: Invalid %s property (%d)\n",
@@ -326,8 +579,7 @@ 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 +606,26 @@ 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 +655,8 @@ 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 +986,48 @@ 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: Zero or positive performance state on success, otherwise negative
+ * value on errors.
  */
-struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
-						   struct device_node *np)
+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;
+	int pstate = -EINVAL;
 
-	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 -EINVAL;
 
-	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..e24d81497375 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;
@@ -133,13 +135,21 @@ 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.
  * @clk: Device's clock handle
  * @regulators: Supply regulators
- * @regulator_count: Number of power supply regulators
+ * @regulator_count: Number of power supply regulators. Its value can be -1
+ * (uninitialized), 0 (no opp-microvolt property) or > 0 (has opp-microvolt
+ * property).
  * @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).
@@ -171,13 +181,19 @@ 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;
 	struct clk *clk;
 	struct regulator **regulators;
-	unsigned int regulator_count;
+	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 +222,16 @@ 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