// SPDX-License-Identifier: GPL-2.0-only

  /*
   * Generic OPP OF helpers
   *
   * Copyright (C) 2009-2010 Texas Instruments Incorporated.
   *	Nishanth Menon
   *	Romit Dasgupta
   *	Kevin Hilman

   */
  
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #include <linux/cpu.h>
  #include <linux/errno.h>
  #include <linux/device.h>

  #include <linux/of_device.h>

  #include <linux/pm_domain.h>

  #include <linux/slab.h>

  #include <linux/export.h>

  #include <linux/energy_model.h>

  
  #include "opp.h"

  /*
   * Returns opp descriptor node for a device node, caller must
   * do of_node_put().
   */
  static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
  						     int index)
  {
  	/* "operating-points-v2" can be an array for power domain providers */
  	return of_parse_phandle(np, "operating-points-v2", index);
  }
  
  /* Returns opp descriptor node for a device, caller must do of_node_put() */
  struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
  {
  	return _opp_of_get_opp_desc_node(dev->of_node, 0);
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

  struct opp_table *_managed_opp(struct device *dev, int index)

  {

  	struct opp_table *opp_table, *managed_table = NULL;

  	struct device_node *np;

  	np = _opp_of_get_opp_desc_node(dev->of_node, index);
  	if (!np)
  		return NULL;

  	list_for_each_entry(opp_table, &opp_tables, node) {

  		if (opp_table->np == np) {
  			/*
  			 * Multiple devices can point to the same OPP table and
  			 * so will have same node-pointer, np.
  			 *
  			 * But the OPPs will be considered as shared only if the
  			 * OPP table contains a "opp-shared" property.
  			 */

  			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
  				_get_opp_table_kref(opp_table);
  				managed_table = opp_table;
  			}

  			break;

  		}
  	}

  	of_node_put(np);

  
  	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;

  	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
  ",
  		       __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;
  	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);
  
  	opp_table->required_opp_count = 0;
  	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_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
  ");
  		return;
  	}
  
  	count = of_count_phandle_with_args(np, "required-opps", NULL);
  	if (!count)
  		goto put_np;
  
  	required_opp_tables = kcalloc(count, sizeof(*required_opp_tables),
  				      GFP_KERNEL);

  	if (!required_opp_tables)

  		goto put_np;
  
  	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
  ",
  				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)

  {

  	struct device_node *np, *opp_np;
  	u32 val;

  
  	/*
  	 * Only required for backward compatibility with v1 bindings, but isn't
  	 * harmful for other cases. And so we do it unconditionally.
  	 */
  	np = of_node_get(dev->of_node);

  	if (!np)
  		return;
  
  	if (!of_property_read_u32(np, "clock-latency", &val))
  		opp_table->clock_latency_ns_max = val;
  	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);
  
  	if (!opp_np)
  		return;
  
  	if (of_property_read_bool(opp_np, "opp-shared"))
  		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
  	else
  		opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
  
  	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)
  ",
  			       __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)
  {
  	unsigned int count = opp_table->supported_hw_count;
  	u32 version;
  	int ret;

  	if (!opp_table->supported_hw) {
  		/*
  		 * In the case that no supported_hw has been set by the
  		 * platform but there is an opp-supported-hw value set for
  		 * an OPP then the OPP should not be enabled as there is
  		 * no way to see if the hardware supports it.
  		 */
  		if (of_find_property(np, "opp-supported-hw", NULL))
  			return false;
  		else
  			return true;
  	}

  
  	while (count--) {
  		ret = of_property_read_u32_index(np, "opp-supported-hw", count,
  						 &version);
  		if (ret) {
  			dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d
  ",
  				 __func__, count, ret);
  			return false;
  		}
  
  		/* Both of these are bitwise masks of the versions */
  		if (!(version & opp_table->supported_hw[count]))
  			return false;
  	}
  
  	return true;
  }

  static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
  			      struct opp_table *opp_table)
  {

  	u32 *microvolt, *microamp = NULL;

  	int supplies = opp_table->regulator_count, vcount, icount, ret, i, j;

  	struct property *prop = NULL;
  	char name[NAME_MAX];
  
  	/* Search for "opp-microvolt-<name>" */
  	if (opp_table->prop_name) {
  		snprintf(name, sizeof(name), "opp-microvolt-%s",
  			 opp_table->prop_name);
  		prop = of_find_property(opp->np, name, NULL);
  	}
  
  	if (!prop) {
  		/* Search for "opp-microvolt" */
  		sprintf(name, "opp-microvolt");
  		prop = of_find_property(opp->np, name, NULL);
  
  		/* Missing property isn't a problem, but an invalid entry is */

  		if (!prop) {

  			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
  ",
  				__func__);
  			return -EINVAL;
  		}

  	}

  	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
  ", __func__);
  		return -EINVAL;
  	}

  	vcount = of_property_count_u32_elems(opp->np, name);
  	if (vcount < 0) {

  		dev_err(dev, "%s: Invalid %s property (%d)
  ",

  			__func__, name, vcount);
  		return vcount;

  	}

  	/* There can be one or three elements per supply */
  	if (vcount != supplies && vcount != supplies * 3) {
  		dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)
  ",
  			__func__, name, vcount, supplies);

  		return -EINVAL;
  	}

  	microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
  	if (!microvolt)
  		return -ENOMEM;
  
  	ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);

  	if (ret) {
  		dev_err(dev, "%s: error parsing %s: %d
  ", __func__, name, ret);

  		ret = -EINVAL;
  		goto free_microvolt;

  	}
  
  	/* Search for "opp-microamp-<name>" */
  	prop = NULL;
  	if (opp_table->prop_name) {
  		snprintf(name, sizeof(name), "opp-microamp-%s",
  			 opp_table->prop_name);
  		prop = of_find_property(opp->np, name, NULL);
  	}
  
  	if (!prop) {
  		/* Search for "opp-microamp" */
  		sprintf(name, "opp-microamp");
  		prop = of_find_property(opp->np, name, NULL);
  	}

  	if (prop) {
  		icount = of_property_count_u32_elems(opp->np, name);
  		if (icount < 0) {
  			dev_err(dev, "%s: Invalid %s property (%d)
  ", __func__,
  				name, icount);
  			ret = icount;
  			goto free_microvolt;
  		}

  		if (icount != supplies) {
  			dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)
  ",
  				__func__, name, icount, supplies);
  			ret = -EINVAL;
  			goto free_microvolt;
  		}
  
  		microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
  		if (!microamp) {
  			ret = -EINVAL;
  			goto free_microvolt;
  		}
  
  		ret = of_property_read_u32_array(opp->np, name, microamp,
  						 icount);
  		if (ret) {
  			dev_err(dev, "%s: error parsing %s: %d
  ", __func__,
  				name, ret);
  			ret = -EINVAL;
  			goto free_microamp;
  		}
  	}
  
  	for (i = 0, j = 0; i < supplies; i++) {
  		opp->supplies[i].u_volt = microvolt[j++];
  
  		if (vcount == supplies) {
  			opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
  			opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
  		} else {
  			opp->supplies[i].u_volt_min = microvolt[j++];
  			opp->supplies[i].u_volt_max = microvolt[j++];
  		}
  
  		if (microamp)
  			opp->supplies[i].u_amp = microamp[i];
  	}
  
  free_microamp:
  	kfree(microamp);
  free_microvolt:
  	kfree(microvolt);
  
  	return ret;

  }
  
  /**
   * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
   *				  entries
   * @dev:	device pointer used to lookup OPP table.
   *
   * Free OPPs created using static entries present in DT.

   */
  void dev_pm_opp_of_remove_table(struct device *dev)
  {

  	_dev_pm_opp_find_and_remove_table(dev);

  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

  /**
   * _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
   *
   * This function adds an opp definition to the opp table and returns status. The
   * opp can be controlled using dev_pm_opp_enable/disable functions and may be
   * removed by dev_pm_opp_remove.
   *

   * Return:

   * Valid OPP pointer:
   *		On success
   * NULL:

   *		Duplicate OPPs (both freq and volt are same) and opp->available

   *		OR if the OPP is not supported by hardware.
   * ERR_PTR(-EEXIST):
   *		Freq are same and volt are different OR

   *		Duplicate OPPs (both freq and volt are same) and !opp->available

   * ERR_PTR(-ENOMEM):
   *		Memory allocation failure
   * ERR_PTR(-EINVAL):
   *		Failed parsing the OPP node

   */

  static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
  		struct device *dev, struct device_node *np)

  {

  	struct dev_pm_opp *new_opp;

  	u64 rate = 0;

  	u32 val;
  	int ret;

  	bool rate_not_available = false;

  	new_opp = _opp_allocate(opp_table);
  	if (!new_opp)

  		return ERR_PTR(-ENOMEM);

  
  	ret = of_property_read_u64(np, "opp-hz", &rate);
  	if (ret < 0) {

  		/* "opp-hz" is optional for devices like power domains. */

  		if (!opp_table->is_genpd) {

  			dev_err(dev, "%s: opp-hz not found
  ", __func__);
  			goto free_opp;
  		}
  
  		rate_not_available = true;
  	} else {
  		/*
  		 * Rate is defined as an unsigned long in clk API, and so
  		 * casting explicitly to its type. Must be fixed once rate is 64
  		 * bit guaranteed in clk API.
  		 */
  		new_opp->rate = (unsigned long)rate;

  	}

  	of_property_read_u32(np, "opp-level", &new_opp->level);

  	/* Check if the OPP supports hardware's hierarchy of versions or not */
  	if (!_opp_is_supported(dev, opp_table, np)) {
  		dev_dbg(dev, "OPP not supported by hardware: %llu
  ", rate);
  		goto free_opp;
  	}

  	new_opp->turbo = of_property_read_bool(np, "turbo-mode");
  
  	new_opp->np = np;
  	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;
  
  	ret = opp_parse_supplies(new_opp, dev, opp_table);
  	if (ret)

  		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_required_opps;

  	}

  
  	/* OPP to select on device suspend */
  	if (of_property_read_bool(np, "opp-suspend")) {
  		if (opp_table->suspend_opp) {

  			/* Pick the OPP with higher rate as suspend OPP */
  			if (new_opp->rate > opp_table->suspend_opp->rate) {
  				opp_table->suspend_opp->suspend = false;
  				new_opp->suspend = true;
  				opp_table->suspend_opp = new_opp;
  			}

  		} else {
  			new_opp->suspend = true;
  			opp_table->suspend_opp = new_opp;
  		}
  	}
  
  	if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
  		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

  	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu
  ",

  		 __func__, new_opp->turbo, new_opp->rate,

  		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
  		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);

  
  	/*
  	 * Notify the changes in the availability of the operable
  	 * frequency/voltage list.
  	 */

  	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);

  	return ERR_PTR(ret);

  }
  
  /* Initializes OPP tables based on new bindings */

  static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)

  {
  	struct device_node *np;

  	int ret, count = 0, pstate_count = 0;

  	struct dev_pm_opp *opp;

  	/* OPP table is already initialized for the device */
  	if (opp_table->parsed_static_opps) {
  		kref_get(&opp_table->list_kref);
  		return 0;
  	}

  	/*
  	 * Re-initialize list_kref every time we add static OPPs to the OPP
  	 * table as the reference count may be 0 after the last tie static OPPs
  	 * were removed.
  	 */
  	kref_init(&opp_table->list_kref);

  	/* We have opp-table node now, iterate over it and add OPPs */

  	for_each_available_child_of_node(opp_table->np, np) {

  		opp = _opp_add_static_v2(opp_table, dev, np);
  		if (IS_ERR(opp)) {
  			ret = PTR_ERR(opp);

  			dev_err(dev, "%s: Failed to add OPP, %d
  ", __func__,
  				ret);

  			of_node_put(np);

  			goto put_list_kref;

  		} else if (opp) {
  			count++;

  		}
  	}
  
  	/* There should be one of more OPP defined */

  	if (WARN_ON(!count)) {
  		ret = -ENOENT;
  		goto put_list_kref;
  	}

  	list_for_each_entry(opp, &opp_table->opp_list, node)
  		pstate_count += !!opp->pstate;
  
  	/* Either all or none of the nodes shall have performance state set */
  	if (pstate_count && pstate_count != count) {
  		dev_err(dev, "Not all nodes have performance state set (%d: %d)
  ",
  			count, pstate_count);

  		ret = -ENOENT;
  		goto put_list_kref;

  	}
  
  	if (pstate_count)
  		opp_table->genpd_performance_state = true;

  	opp_table->parsed_static_opps = true;

  	return 0;

  
  put_list_kref:
  	_put_opp_list_kref(opp_table);
  
  	return ret;

  }
  
  /* 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, ret = 0;

  
  	prop = of_find_property(dev->of_node, "operating-points", NULL);
  	if (!prop)
  		return -ENODEV;
  	if (!prop->value)
  		return -ENODATA;
  
  	/*
  	 * Each OPP is a set of tuples consisting of frequency and
  	 * voltage like <freq-kHz vol-uV>.
  	 */
  	nr = prop->length / sizeof(u32);
  	if (nr % 2) {
  		dev_err(dev, "%s: Invalid OPP table
  ", __func__);
  		return -EINVAL;
  	}
  
  	val = prop->value;
  	while (nr) {
  		unsigned long freq = be32_to_cpup(val++) * 1000;
  		unsigned long volt = be32_to_cpup(val++);

  		ret = _opp_add_v1(opp_table, dev, freq, volt, false);

  		if (ret) {
  			dev_err(dev, "%s: Failed to add OPP %ld (%d)
  ",
  				__func__, freq, ret);

  			_put_opp_list_kref(opp_table);

  			return ret;

  		}

  		nr -= 2;
  	}

  	return ret;

  }
  
  /**
   * dev_pm_opp_of_add_table() - Initialize opp table from device tree
   * @dev:	device pointer used to lookup OPP table.
   *
   * Register the initial OPP table with the OPP library for given device.
   *

   * Return:
   * 0		On success OR
   *		Duplicate OPPs (both freq and volt are same) and opp->available
   * -EEXIST	Freq are same and volt are different OR
   *		Duplicate OPPs (both freq and volt are same) and !opp->available
   * -ENOMEM	Memory allocation failure
   * -ENODEV	when 'operating-points' property is not found or is invalid data
   *		in device node.
   * -ENODATA	when empty 'operating-points' property is found
   * -EINVAL	when invalid entries are found in opp-v2 table
   */
  int dev_pm_opp_of_add_table(struct device *dev)
  {

  	struct opp_table *opp_table;

  	int ret;

  	opp_table = dev_pm_opp_get_opp_table_indexed(dev, 0);
  	if (!opp_table)
  		return -ENOMEM;

  	/*

  	 * OPPs have two version of bindings now. Also try the old (v1)
  	 * bindings for backward compatibility with older dtbs.

  	 */

  	if (opp_table->np)
  		ret = _of_add_opp_table_v2(dev, opp_table);
  	else
  		ret = _of_add_opp_table_v1(dev, opp_table);

  	if (ret)
  		dev_pm_opp_put_opp_table(opp_table);

  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);

  /**
   * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
   * @dev:	device pointer used to lookup OPP table.
   * @index:	Index number.
   *
   * Register the initial OPP table with the OPP library for given device only
   * using the "operating-points-v2" property.
   *
   * Return:
   * 0		On success OR
   *		Duplicate OPPs (both freq and volt are same) and opp->available
   * -EEXIST	Freq are same and volt are different OR
   *		Duplicate OPPs (both freq and volt are same) and !opp->available
   * -ENOMEM	Memory allocation failure
   * -ENODEV	when 'operating-points' property is not found or is invalid data
   *		in device node.
   * -ENODATA	when empty 'operating-points' property is found
   * -EINVAL	when invalid entries are found in opp-v2 table
   */
  int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
  {

  	struct opp_table *opp_table;

  	int ret, count;

  	if (index) {

  		/*
  		 * If only one phandle is present, then the same OPP table
  		 * applies for all index requests.
  		 */
  		count = of_count_phandle_with_args(dev->of_node,
  						   "operating-points-v2", NULL);

  		if (count == 1)
  			index = 0;

  	}

  	opp_table = dev_pm_opp_get_opp_table_indexed(dev, index);
  	if (!opp_table)
  		return -ENOMEM;
  
  	ret = _of_add_opp_table_v2(dev, opp_table);
  	if (ret)
  		dev_pm_opp_put_opp_table(opp_table);

  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);

  /* CPU device specific helpers */
  
  /**
   * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
   * @cpumask:	cpumask for which OPP table needs to be removed
   *
   * This removes the OPP tables for CPUs present in the @cpumask.
   * This should be used only to remove static entries created from DT.

   */
  void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
  {

  	_dev_pm_opp_cpumask_remove_table(cpumask, -1);

  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
  
  /**
   * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
   * @cpumask:	cpumask for which OPP table needs to be added.
   *
   * This adds the OPP tables for CPUs present in the @cpumask.

   */
  int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
  {
  	struct device *cpu_dev;

  	int cpu, ret;

  	if (WARN_ON(cpumask_empty(cpumask)))
  		return -ENODEV;

  
  	for_each_cpu(cpu, cpumask) {
  		cpu_dev = get_cpu_device(cpu);
  		if (!cpu_dev) {
  			pr_err("%s: failed to get cpu%d device
  ", __func__,
  			       cpu);

  			ret = -ENODEV;
  			goto remove_table;

  		}
  
  		ret = dev_pm_opp_of_add_table(cpu_dev);
  		if (ret) {

  			/*
  			 * OPP may get registered dynamically, don't print error
  			 * message here.
  			 */
  			pr_debug("%s: couldn't find opp table for cpu:%d, %d
  ",
  				 __func__, cpu, ret);

  			goto remove_table;

  		}
  	}

  	return 0;
  
  remove_table:
  	/* Free all other OPPs */
  	_dev_pm_opp_cpumask_remove_table(cpumask, cpu);

  	return ret;
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
  
  /*
   * Works only for OPP v2 bindings.
   *
   * Returns -ENOENT if operating-points-v2 bindings aren't supported.
   */
  /**
   * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
   *				      @cpu_dev using operating-points-v2
   *				      bindings.
   *
   * @cpu_dev:	CPU device for which we do this operation
   * @cpumask:	cpumask to update with information of sharing CPUs
   *
   * 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.

   */
  int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
  				   struct cpumask *cpumask)
  {

  	struct device_node *np, *tmp_np, *cpu_np;

  	int cpu, ret = 0;
  
  	/* Get OPP descriptor node */

  	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);

  	if (!np) {

  		dev_dbg(cpu_dev, "%s: Couldn't find opp node.
  ", __func__);

  		return -ENOENT;
  	}
  
  	cpumask_set_cpu(cpu_dev->id, cpumask);
  
  	/* OPPs are shared ? */
  	if (!of_property_read_bool(np, "opp-shared"))
  		goto put_cpu_node;
  
  	for_each_possible_cpu(cpu) {
  		if (cpu == cpu_dev->id)
  			continue;

  		cpu_np = of_cpu_device_node_get(cpu);

  		if (!cpu_np) {
  			dev_err(cpu_dev, "%s: failed to get cpu%d node
  ",

  				__func__, cpu);

  			ret = -ENOENT;

  			goto put_cpu_node;
  		}
  
  		/* Get OPP descriptor node */

  		tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);

  		of_node_put(cpu_np);

  		if (!tmp_np) {

  			pr_err("%pOF: Couldn't find opp node
  ", cpu_np);

  			ret = -ENOENT;
  			goto put_cpu_node;
  		}
  
  		/* CPUs are sharing opp node */
  		if (np == tmp_np)
  			cpumask_set_cpu(cpu, cpumask);
  
  		of_node_put(tmp_np);
  	}
  
  put_cpu_node:
  	of_node_put(np);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);

  
  /**

   * 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 performance state of the OPP pointed out by the "required-opps"
   * property at @index in @np.

   *

   * Return: Zero or positive performance state on success, otherwise negative
   * value on errors.

   */

  int of_get_required_opp_performance_state(struct device_node *np, int index)

  {

  	struct dev_pm_opp *opp;

  	struct device_node *required_np;
  	struct opp_table *opp_table;

  	int pstate = -EINVAL;

  	required_np = of_parse_required_opp(np, index);
  	if (!required_np)

  		return -EINVAL;

  	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
  ",
  		       __func__, np, PTR_ERR(opp_table));
  		goto put_required_np;

  	}

  	opp = _find_opp_of_np(opp_table, required_np);
  	if (opp) {
  		pstate = opp->pstate;
  		dev_pm_opp_put(opp);

  	}

  	dev_pm_opp_put_opp_table(opp_table);

  put_required_np:

  	of_node_put(required_np);

  	return pstate;

  }

  EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);

  
  /**
   * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
   * @opp:	opp for which DT node has to be returned for
   *
   * Return: DT node corresponding to the opp, else 0 on success.
   *
   * The caller needs to put the node with of_node_put() after using it.
   */
  struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
  {
  	if (IS_ERR_OR_NULL(opp)) {
  		pr_err("%s: Invalid parameters
  ", __func__);
  		return NULL;
  	}
  
  	return of_node_get(opp->np);
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);

  
  /*
   * Callback function provided to the Energy Model framework upon registration.
   * This computes the power estimated by @CPU at @kHz if it is the frequency
   * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise
   * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
   * frequency and @mW to the associated power. The power is estimated as
   * P = C * V^2 * f with C being the CPU's capacitance and V and f respectively
   * the voltage and frequency of the OPP.
   *
   * Returns -ENODEV if the CPU device cannot be found, -EINVAL if the power
   * calculation failed because of missing parameters, 0 otherwise.
   */
  static int __maybe_unused _get_cpu_power(unsigned long *mW, unsigned long *kHz,
  					 int cpu)
  {
  	struct device *cpu_dev;
  	struct dev_pm_opp *opp;
  	struct device_node *np;
  	unsigned long mV, Hz;
  	u32 cap;
  	u64 tmp;
  	int ret;
  
  	cpu_dev = get_cpu_device(cpu);
  	if (!cpu_dev)
  		return -ENODEV;
  
  	np = of_node_get(cpu_dev->of_node);
  	if (!np)
  		return -EINVAL;
  
  	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
  	of_node_put(np);
  	if (ret)
  		return -EINVAL;
  
  	Hz = *kHz * 1000;
  	opp = dev_pm_opp_find_freq_ceil(cpu_dev, &Hz);
  	if (IS_ERR(opp))
  		return -EINVAL;
  
  	mV = dev_pm_opp_get_voltage(opp) / 1000;
  	dev_pm_opp_put(opp);
  	if (!mV)
  		return -EINVAL;
  
  	tmp = (u64)cap * mV * mV * (Hz / 1000000);
  	do_div(tmp, 1000000000);
  
  	*mW = (unsigned long)tmp;
  	*kHz = Hz / 1000;
  
  	return 0;
  }
  
  /**
   * dev_pm_opp_of_register_em() - Attempt to register an Energy Model
   * @cpus	: CPUs for which an Energy Model has to be registered
   *
   * This checks whether the "dynamic-power-coefficient" devicetree property has
   * been specified, and tries to register an Energy Model with it if it has.
   */
  void dev_pm_opp_of_register_em(struct cpumask *cpus)
  {
  	struct em_data_callback em_cb = EM_DATA_CB(_get_cpu_power);
  	int ret, nr_opp, cpu = cpumask_first(cpus);
  	struct device *cpu_dev;
  	struct device_node *np;
  	u32 cap;
  
  	cpu_dev = get_cpu_device(cpu);
  	if (!cpu_dev)
  		return;
  
  	nr_opp = dev_pm_opp_get_opp_count(cpu_dev);
  	if (nr_opp <= 0)
  		return;
  
  	np = of_node_get(cpu_dev->of_node);
  	if (!np)
  		return;
  
  	/*
  	 * Register an EM only if the 'dynamic-power-coefficient' property is
  	 * set in devicetree. It is assumed the voltage values are known if that
  	 * property is set since it is useless otherwise. If voltages are not
  	 * known, just let the EM registration fail with an error to alert the
  	 * user about the inconsistent configuration.
  	 */
  	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
  	of_node_put(np);
  	if (ret || !cap)
  		return;
  
  	em_register_perf_domain(cpus, nr_opp, &em_cb);
  }
  EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em);