// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic OPP Interface
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/clk.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/pm_domain.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/xarray.h>

#include "opp.h"

/*
 * The root of the list of all opp-tables. All opp_table structures branch off
 * from here, with each opp_table containing the list of opps it supports in
 * various states of availability.
 */
LIST_HEAD(opp_tables);

/* Lock to allow exclusive modification to the device and opp lists */
DEFINE_MUTEX(opp_table_lock);
/* Flag indicating that opp_tables list is being updated at the moment */
static bool opp_tables_busy;

/* OPP ID allocator */
static DEFINE_XARRAY_ALLOC1(opp_configs);

static bool _find_opp_dev(const struct device *dev, struct opp_table *opp_table)
{
	struct opp_device *opp_dev;
	bool found = false;

	mutex_lock(&opp_table->lock);
	list_for_each_entry(opp_dev, &opp_table->dev_list, node)
		if (opp_dev->dev == dev) {
			found = true;
			break;
		}

	mutex_unlock(&opp_table->lock);
	return found;
}

static struct opp_table *_find_opp_table_unlocked(struct device *dev)
{
	struct opp_table *opp_table;

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (_find_opp_dev(dev, opp_table)) {
			_get_opp_table_kref(opp_table);
			return opp_table;
		}
	}

	return ERR_PTR(-ENODEV);
}

/**
 * _find_opp_table() - find opp_table struct using device pointer
 * @dev:	device pointer used to lookup OPP table
 *
 * Search OPP table for one containing matching device.
 *
 * Return: pointer to 'struct opp_table' if found, otherwise -ENODEV or
 * -EINVAL based on type of error.
 *
 * The callers must call dev_pm_opp_put_opp_table() after the table is used.
 */
struct opp_table *_find_opp_table(struct device *dev)
{
	struct opp_table *opp_table;

	if (IS_ERR_OR_NULL(dev)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return ERR_PTR(-EINVAL);
	}

	mutex_lock(&opp_table_lock);
	opp_table = _find_opp_table_unlocked(dev);
	mutex_unlock(&opp_table_lock);

	return opp_table;
}

/*
 * Returns true if multiple clocks aren't there, else returns false with WARN.
 *
 * We don't force clk_count == 1 here as there are users who don't have a clock
 * representation in the OPP table and manage the clock configuration themselves
 * in an platform specific way.
 */
static bool assert_single_clk(struct opp_table *opp_table)
{
	return !WARN_ON(opp_table->clk_count > 1);
}

/**
 * dev_pm_opp_get_voltage() - Gets the voltage corresponding to an opp
 * @opp:	opp for which voltage has to be returned for
 *
 * Return: voltage in micro volt corresponding to the opp, else
 * return 0
 *
 * This is useful only for devices with single power supply.
 */
unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
	if (IS_ERR_OR_NULL(opp)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return 0;
	}

	return opp->supplies[0].u_volt;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);

/**
 * dev_pm_opp_get_supplies() - Gets the supply information corresponding to an opp
 * @opp:	opp for which voltage has to be returned for
 * @supplies:	Placeholder for copying the supply information.
 *
 * Return: negative error number on failure, 0 otherwise on success after
 * setting @supplies.
 *
 * This can be used for devices with any number of power supplies. The caller
 * must ensure the @supplies array must contain space for each regulator.
 */
int dev_pm_opp_get_supplies(struct dev_pm_opp *opp,
			    struct dev_pm_opp_supply *supplies)
{
	if (IS_ERR_OR_NULL(opp) || !supplies) {
		pr_err("%s: Invalid parameters\n", __func__);
		return -EINVAL;
	}

	memcpy(supplies, opp->supplies,
	       sizeof(*supplies) * opp->opp_table->regulator_count);
	return 0;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_supplies);

/**
 * dev_pm_opp_get_power() - Gets the power corresponding to an opp
 * @opp:	opp for which power has to be returned for
 *
 * Return: power in micro watt corresponding to the opp, else
 * return 0
 *
 * This is useful only for devices with single power supply.
 */
unsigned long dev_pm_opp_get_power(struct dev_pm_opp *opp)
{
	unsigned long opp_power = 0;
	int i;

	if (IS_ERR_OR_NULL(opp)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return 0;
	}
	for (i = 0; i < opp->opp_table->regulator_count; i++)
		opp_power += opp->supplies[i].u_watt;

	return opp_power;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_power);

/**
 * dev_pm_opp_get_freq_indexed() - Gets the frequency corresponding to an
 *				   available opp with specified index
 * @opp: opp for which frequency has to be returned for
 * @index: index of the frequency within the required opp
 *
 * Return: frequency in hertz corresponding to the opp with specified index,
 * else return 0
 */
unsigned long dev_pm_opp_get_freq_indexed(struct dev_pm_opp *opp, u32 index)
{
	if (IS_ERR_OR_NULL(opp) || index >= opp->opp_table->clk_count) {
		pr_err("%s: Invalid parameters\n", __func__);
		return 0;
	}

	return opp->rates[index];
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq_indexed);

/**
 * dev_pm_opp_get_level() - Gets the level corresponding to an available opp
 * @opp:	opp for which level value has to be returned for
 *
 * Return: level read from device tree corresponding to the opp, else
 * return U32_MAX.
 */
unsigned int dev_pm_opp_get_level(struct dev_pm_opp *opp)
{
	if (IS_ERR_OR_NULL(opp) || !opp->available) {
		pr_err("%s: Invalid parameters\n", __func__);
		return 0;
	}

	return opp->level;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_level);

/**
 * dev_pm_opp_get_required_pstate() - Gets the required performance state
 *                                    corresponding to an available opp
 * @opp:	opp for which performance state has to be returned for
 * @index:	index of the required opp
 *
 * Return: performance state read from device tree corresponding to the
 * required opp, else return U32_MAX.
 */
unsigned int dev_pm_opp_get_required_pstate(struct dev_pm_opp *opp,
					    unsigned int index)
{
	if (IS_ERR_OR_NULL(opp) || !opp->available ||
	    index >= opp->opp_table->required_opp_count) {
		pr_err("%s: Invalid parameters\n", __func__);
		return 0;
	}

	/* required-opps not fully initialized yet */
	if (lazy_linking_pending(opp->opp_table))
		return 0;

	/* The required OPP table must belong to a genpd */
	if (unlikely(!opp->opp_table->required_opp_tables[index]->is_genpd)) {
		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
		return 0;
	}

	return opp->required_opps[index]->level;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_required_pstate);

/**
 * dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
 * @opp: opp for which turbo mode is being verified
 *
 * Turbo OPPs are not for normal use, and can be enabled (under certain
 * conditions) for short duration of times to finish high throughput work
 * quickly. Running on them for longer times may overheat the chip.
 *
 * Return: true if opp is turbo opp, else false.
 */
bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
{
	if (IS_ERR_OR_NULL(opp) || !opp->available) {
		pr_err("%s: Invalid parameters\n", __func__);
		return false;
	}

	return opp->turbo;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);

/**
 * dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
 * @dev:	device for which we do this operation
 *
 * Return: This function returns the max clock latency in nanoseconds.
 */
unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
{
	struct opp_table *opp_table;
	unsigned long clock_latency_ns;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return 0;

	clock_latency_ns = opp_table->clock_latency_ns_max;

	dev_pm_opp_put_opp_table(opp_table);

	return clock_latency_ns;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);

/**
 * dev_pm_opp_get_max_volt_latency() - Get max voltage latency in nanoseconds
 * @dev: device for which we do this operation
 *
 * Return: This function returns the max voltage latency in nanoseconds.
 */
unsigned long dev_pm_opp_get_max_volt_latency(struct device *dev)
{
	struct opp_table *opp_table;
	struct dev_pm_opp *opp;
	struct regulator *reg;
	unsigned long latency_ns = 0;
	int ret, i, count;
	struct {
		unsigned long min;
		unsigned long max;
	} *uV;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return 0;

	/* Regulator may not be required for the device */
	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;

	mutex_lock(&opp_table->lock);

	for (i = 0; i < count; i++) {
		uV[i].min = ~0;
		uV[i].max = 0;

		list_for_each_entry(opp, &opp_table->opp_list, node) {
			if (!opp->available)
				continue;

			if (opp->supplies[i].u_volt_min < uV[i].min)
				uV[i].min = opp->supplies[i].u_volt_min;
			if (opp->supplies[i].u_volt_max > uV[i].max)
				uV[i].max = opp->supplies[i].u_volt_max;
		}
	}

	mutex_unlock(&opp_table->lock);

	/*
	 * The caller needs to ensure that opp_table (and hence the regulator)
	 * isn't freed, while we are executing this routine.
	 */
	for (i = 0; i < count; i++) {
		reg = opp_table->regulators[i];
		ret = regulator_set_voltage_time(reg, uV[i].min, uV[i].max);
		if (ret > 0)
			latency_ns += ret * 1000;
	}

	kfree(uV);
put_opp_table:
	dev_pm_opp_put_opp_table(opp_table);

	return latency_ns;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_volt_latency);

/**
 * dev_pm_opp_get_max_transition_latency() - Get max transition latency in
 *					     nanoseconds
 * @dev: device for which we do this operation
 *
 * Return: This function returns the max transition latency, in nanoseconds, to
 * switch from one OPP to other.
 */
unsigned long dev_pm_opp_get_max_transition_latency(struct device *dev)
{
	return dev_pm_opp_get_max_volt_latency(dev) +
		dev_pm_opp_get_max_clock_latency(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_transition_latency);

/**
 * dev_pm_opp_get_suspend_opp_freq() - Get frequency of suspend opp in Hz
 * @dev:	device for which we do this operation
 *
 * Return: This function returns the frequency of the OPP marked as suspend_opp
 * if one is available, else returns 0;
 */
unsigned long dev_pm_opp_get_suspend_opp_freq(struct device *dev)
{
	struct opp_table *opp_table;
	unsigned long freq = 0;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return 0;

	if (opp_table->suspend_opp && opp_table->suspend_opp->available)
		freq = dev_pm_opp_get_freq(opp_table->suspend_opp);

	dev_pm_opp_put_opp_table(opp_table);

	return freq;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp_freq);

int _get_opp_count(struct opp_table *opp_table)
{
	struct dev_pm_opp *opp;
	int count = 0;

	mutex_lock(&opp_table->lock);

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		if (opp->available)
			count++;
	}

	mutex_unlock(&opp_table->lock);

	return count;
}

/**
 * dev_pm_opp_get_opp_count() - Get number of opps available in the opp table
 * @dev:	device for which we do this operation
 *
 * Return: This function returns the number of available opps if there are any,
 * else returns 0 if none or the corresponding error value.
 */
int dev_pm_opp_get_opp_count(struct device *dev)
{
	struct opp_table *opp_table;
	int count;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		count = PTR_ERR(opp_table);
		dev_dbg(dev, "%s: OPP table not found (%d)\n",
			__func__, count);
		return count;
	}

	count = _get_opp_count(opp_table);
	dev_pm_opp_put_opp_table(opp_table);

	return count;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);

/* Helpers to read keys */
static unsigned long _read_freq(struct dev_pm_opp *opp, int index)
{
	return opp->rates[index];
}

static unsigned long _read_level(struct dev_pm_opp *opp, int index)
{
	return opp->level;
}

static unsigned long _read_bw(struct dev_pm_opp *opp, int index)
{
	return opp->bandwidth[index].peak;
}

/* Generic comparison helpers */
static bool _compare_exact(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
			   unsigned long opp_key, unsigned long key)
{
	if (opp_key == key) {
		*opp = temp_opp;
		return true;
	}

	return false;
}

static bool _compare_ceil(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
			  unsigned long opp_key, unsigned long key)
{
	if (opp_key >= key) {
		*opp = temp_opp;
		return true;
	}

	return false;
}

static bool _compare_floor(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
			   unsigned long opp_key, unsigned long key)
{
	if (opp_key > key)
		return true;

	*opp = temp_opp;
	return false;
}

/* Generic key finding helpers */
static struct dev_pm_opp *_opp_table_find_key(struct opp_table *opp_table,
		unsigned long *key, int index, bool available,
		unsigned long (*read)(struct dev_pm_opp *opp, int index),
		bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
				unsigned long opp_key, unsigned long key),
		bool (*assert)(struct opp_table *opp_table))
{
	struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);

	/* Assert that the requirement is met */
	if (assert && !assert(opp_table))
		return ERR_PTR(-EINVAL);

	mutex_lock(&opp_table->lock);

	list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
		if (temp_opp->available == available) {
			if (compare(&opp, temp_opp, read(temp_opp, index), *key))
				break;
		}
	}

	/* Increment the reference count of OPP */
	if (!IS_ERR(opp)) {
		*key = read(opp, index);
		dev_pm_opp_get(opp);
	}

	mutex_unlock(&opp_table->lock);

	return opp;
}

static struct dev_pm_opp *
_find_key(struct device *dev, unsigned long *key, int index, bool available,
	  unsigned long (*read)(struct dev_pm_opp *opp, int index),
	  bool (*compare)(struct dev_pm_opp **opp, struct dev_pm_opp *temp_opp,
			  unsigned long opp_key, unsigned long key),
	  bool (*assert)(struct opp_table *opp_table))
{
	struct opp_table *opp_table;
	struct dev_pm_opp *opp;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		dev_err(dev, "%s: OPP table not found (%ld)\n", __func__,
			PTR_ERR(opp_table));
		return ERR_CAST(opp_table);
	}

	opp = _opp_table_find_key(opp_table, key, index, available, read,
				  compare, assert);

	dev_pm_opp_put_opp_table(opp_table);

	return opp;
}

static struct dev_pm_opp *_find_key_exact(struct device *dev,
		unsigned long key, int index, bool available,
		unsigned long (*read)(struct dev_pm_opp *opp, int index),
		bool (*assert)(struct opp_table *opp_table))
{
	/*
	 * The value of key will be updated here, but will be ignored as the
	 * caller doesn't need it.
	 */
	return _find_key(dev, &key, index, available, read, _compare_exact,
			 assert);
}

static struct dev_pm_opp *_opp_table_find_key_ceil(struct opp_table *opp_table,
		unsigned long *key, int index, bool available,
		unsigned long (*read)(struct dev_pm_opp *opp, int index),
		bool (*assert)(struct opp_table *opp_table))
{
	return _opp_table_find_key(opp_table, key, index, available, read,
				   _compare_ceil, assert);
}

static struct dev_pm_opp *_find_key_ceil(struct device *dev, unsigned long *key,
		int index, bool available,
		unsigned long (*read)(struct dev_pm_opp *opp, int index),
		bool (*assert)(struct opp_table *opp_table))
{
	return _find_key(dev, key, index, available, read, _compare_ceil,
			 assert);
}

static struct dev_pm_opp *_find_key_floor(struct device *dev,
		unsigned long *key, int index, bool available,
		unsigned long (*read)(struct dev_pm_opp *opp, int index),
		bool (*assert)(struct opp_table *opp_table))
{
	return _find_key(dev, key, index, available, read, _compare_floor,
			 assert);
}

/**
 * dev_pm_opp_find_freq_exact() - search for an exact frequency
 * @dev:		device for which we do this operation
 * @freq:		frequency to search for
 * @available:		true/false - match for available opp
 *
 * Return: Searches for exact match in the opp table and returns pointer to the
 * matching opp if found, else returns ERR_PTR in case of error and should
 * be handled using IS_ERR. Error return values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * Note: available is a modifier for the search. if available=true, then the
 * match is for exact matching frequency and is available in the stored OPP
 * table. if false, the match is for exact frequency which is not available.
 *
 * This provides a mechanism to enable an opp which is not available currently
 * or the opposite as well.
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
		unsigned long freq, bool available)
{
	return _find_key_exact(dev, freq, 0, available, _read_freq,
			       assert_single_clk);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);

/**
 * dev_pm_opp_find_freq_exact_indexed() - Search for an exact freq for the
 *					 clock corresponding to the index
 * @dev:	Device for which we do this operation
 * @freq:	frequency to search for
 * @index:	Clock index
 * @available:	true/false - match for available opp
 *
 * Search for the matching exact OPP for the clock corresponding to the
 * specified index from a starting freq for a device.
 *
 * Return: matching *opp , else returns ERR_PTR in case of error and should be
 * handled using IS_ERR. Error return values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *
dev_pm_opp_find_freq_exact_indexed(struct device *dev, unsigned long freq,
				   u32 index, bool available)
{
	return _find_key_exact(dev, freq, index, available, _read_freq, NULL);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact_indexed);

static noinline struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
						   unsigned long *freq)
{
	return _opp_table_find_key_ceil(opp_table, freq, 0, true, _read_freq,
					assert_single_clk);
}

/**
 * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
 * @dev:	device for which we do this operation
 * @freq:	Start frequency
 *
 * Search for the matching ceil *available* OPP from a starting freq
 * for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
					     unsigned long *freq)
{
	return _find_key_ceil(dev, freq, 0, true, _read_freq, assert_single_clk);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);

/**
 * dev_pm_opp_find_freq_ceil_indexed() - Search for a rounded ceil freq for the
 *					 clock corresponding to the index
 * @dev:	Device for which we do this operation
 * @freq:	Start frequency
 * @index:	Clock index
 *
 * Search for the matching ceil *available* OPP for the clock corresponding to
 * the specified index from a starting freq for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *
dev_pm_opp_find_freq_ceil_indexed(struct device *dev, unsigned long *freq,
				  u32 index)
{
	return _find_key_ceil(dev, freq, index, true, _read_freq, NULL);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil_indexed);

/**
 * dev_pm_opp_find_freq_floor() - Search for a rounded floor freq
 * @dev:	device for which we do this operation
 * @freq:	Start frequency
 *
 * Search for the matching floor *available* OPP from a starting freq
 * for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
					      unsigned long *freq)
{
	return _find_key_floor(dev, freq, 0, true, _read_freq, assert_single_clk);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);

/**
 * dev_pm_opp_find_freq_floor_indexed() - Search for a rounded floor freq for the
 *					  clock corresponding to the index
 * @dev:	Device for which we do this operation
 * @freq:	Start frequency
 * @index:	Clock index
 *
 * Search for the matching floor *available* OPP for the clock corresponding to
 * the specified index from a starting freq for a device.
 *
 * Return: matching *opp and refreshes *freq accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *
dev_pm_opp_find_freq_floor_indexed(struct device *dev, unsigned long *freq,
				   u32 index)
{
	return _find_key_floor(dev, freq, index, true, _read_freq, NULL);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor_indexed);

/**
 * dev_pm_opp_find_level_exact() - search for an exact level
 * @dev:		device for which we do this operation
 * @level:		level to search for
 *
 * Return: Searches for exact match in the opp table and returns pointer to the
 * matching opp if found, else returns ERR_PTR in case of error and should
 * be handled using IS_ERR. Error return values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_level_exact(struct device *dev,
					       unsigned int level)
{
	return _find_key_exact(dev, level, 0, true, _read_level, NULL);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_exact);

/**
 * dev_pm_opp_find_level_ceil() - search for an rounded up level
 * @dev:		device for which we do this operation
 * @level:		level to search for
 *
 * Return: Searches for rounded up match in the opp table and returns pointer
 * to the  matching opp if found, else returns ERR_PTR in case of error and
 * should be handled using IS_ERR. Error return values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_level_ceil(struct device *dev,
					      unsigned int *level)
{
	unsigned long temp = *level;
	struct dev_pm_opp *opp;

	opp = _find_key_ceil(dev, &temp, 0, true, _read_level, NULL);

	/* False match */
	if (temp == OPP_LEVEL_UNSET) {
		dev_err(dev, "%s: OPP levels aren't available\n", __func__);
		dev_pm_opp_put(opp);
		return ERR_PTR(-ENODEV);
	}

	*level = temp;
	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_ceil);

/**
 * dev_pm_opp_find_level_floor() - Search for a rounded floor level
 * @dev:	device for which we do this operation
 * @level:	Start level
 *
 * Search for the matching floor *available* OPP from a starting level
 * for a device.
 *
 * Return: matching *opp and refreshes *level accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_level_floor(struct device *dev,
					       unsigned long *level)
{
	return _find_key_floor(dev, level, 0, true, _read_level, NULL);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_level_floor);

/**
 * dev_pm_opp_find_bw_ceil() - Search for a rounded ceil bandwidth
 * @dev:	device for which we do this operation
 * @bw:	start bandwidth
 * @index:	which bandwidth to compare, in case of OPPs with several values
 *
 * Search for the matching floor *available* OPP from a starting bandwidth
 * for a device.
 *
 * Return: matching *opp and refreshes *bw accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_bw_ceil(struct device *dev, unsigned int *bw,
					   int index)
{
	unsigned long temp = *bw;
	struct dev_pm_opp *opp;

	opp = _find_key_ceil(dev, &temp, index, true, _read_bw, NULL);
	*bw = temp;
	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_bw_ceil);

/**
 * dev_pm_opp_find_bw_floor() - Search for a rounded floor bandwidth
 * @dev:	device for which we do this operation
 * @bw:	start bandwidth
 * @index:	which bandwidth to compare, in case of OPPs with several values
 *
 * Search for the matching floor *available* OPP from a starting bandwidth
 * for a device.
 *
 * Return: matching *opp and refreshes *bw accordingly, else returns
 * ERR_PTR in case of error and should be handled using IS_ERR. Error return
 * values can be:
 * EINVAL:	for bad pointer
 * ERANGE:	no match found for search
 * ENODEV:	if device not found in list of registered devices
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *dev_pm_opp_find_bw_floor(struct device *dev,
					    unsigned int *bw, int index)
{
	unsigned long temp = *bw;
	struct dev_pm_opp *opp;

	opp = _find_key_floor(dev, &temp, index, true, _read_bw, NULL);
	*bw = temp;
	return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_bw_floor);

static int _set_opp_voltage(struct device *dev, struct regulator *reg,
			    struct dev_pm_opp_supply *supply)
{
	int ret;

	/* Regulator not available for device */
	if (IS_ERR(reg)) {
		dev_dbg(dev, "%s: regulator not available: %ld\n", __func__,
			PTR_ERR(reg));
		return 0;
	}

	dev_dbg(dev, "%s: voltages (mV): %lu %lu %lu\n", __func__,
		supply->u_volt_min, supply->u_volt, supply->u_volt_max);

	ret = regulator_set_voltage_triplet(reg, supply->u_volt_min,
					    supply->u_volt, supply->u_volt_max);
	if (ret)
		dev_err(dev, "%s: failed to set voltage (%lu %lu %lu mV): %d\n",
			__func__, supply->u_volt_min, supply->u_volt,
			supply->u_volt_max, ret);

	return ret;
}

static int
_opp_config_clk_single(struct device *dev, struct opp_table *opp_table,
		       struct dev_pm_opp *opp, void *data, bool scaling_down)
{
	unsigned long *target = data;
	unsigned long freq;
	int ret;

	/* One of target and opp must be available */
	if (target) {
		freq = *target;
	} else if (opp) {
		freq = opp->rates[0];
	} else {
		WARN_ON(1);
		return -EINVAL;
	}

	ret = clk_set_rate(opp_table->clk, freq);
	if (ret) {
		dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
			ret);
	} else {
		opp_table->rate_clk_single = freq;
	}

	return ret;
}

/*
 * Simple implementation for configuring multiple clocks. Configure clocks in
 * the order in which they are present in the array while scaling up.
 */
int dev_pm_opp_config_clks_simple(struct device *dev,
		struct opp_table *opp_table, struct dev_pm_opp *opp, void *data,
		bool scaling_down)
{
	int ret, i;

	if (scaling_down) {
		for (i = opp_table->clk_count - 1; i >= 0; i--) {
			ret = clk_set_rate(opp_table->clks[i], opp->rates[i]);
			if (ret) {
				dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
					ret);
				return ret;
			}
		}
	} else {
		for (i = 0; i < opp_table->clk_count; i++) {
			ret = clk_set_rate(opp_table->clks[i], opp->rates[i]);
			if (ret) {
				dev_err(dev, "%s: failed to set clock rate: %d\n", __func__,
					ret);
				return ret;
			}
		}
	}

	return 0;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_config_clks_simple);

static int _opp_config_regulator_single(struct device *dev,
			struct dev_pm_opp *old_opp, struct dev_pm_opp *new_opp,
			struct regulator **regulators, unsigned int count)
{
	struct regulator *reg = regulators[0];
	int ret;

	/* This function only supports single regulator per device */
	if (WARN_ON(count > 1)) {
		dev_err(dev, "multiple regulators are not supported\n");
		return -EINVAL;
	}

	ret = _set_opp_voltage(dev, reg, new_opp->supplies);
	if (ret)
		return ret;

	/*
	 * Enable the regulator after setting its voltages, otherwise it breaks
	 * some boot-enabled regulators.
	 */
	if (unlikely(!new_opp->opp_table->enabled)) {
		ret = regulator_enable(reg);
		if (ret < 0)
			dev_warn(dev, "Failed to enable regulator: %d", ret);
	}

	return 0;
}

static int _set_opp_bw(const struct opp_table *opp_table,
		       struct dev_pm_opp *opp, struct device *dev)
{
	u32 avg, peak;
	int i, ret;

	if (!opp_table->paths)
		return 0;

	for (i = 0; i < opp_table->path_count; i++) {
		if (!opp) {
			avg = 0;
			peak = 0;
		} else {
			avg = opp->bandwidth[i].avg;
			peak = opp->bandwidth[i].peak;
		}
		ret = icc_set_bw(opp_table->paths[i], avg, peak);
		if (ret) {
			dev_err(dev, "Failed to %s bandwidth[%d]: %d\n",
				opp ? "set" : "remove", i, ret);
			return ret;
		}
	}

	return 0;
}

static int _set_performance_state(struct device *dev, struct device *pd_dev,
				  struct dev_pm_opp *opp, int i)
{
	unsigned int pstate = 0;
	int ret;

	if (!pd_dev)
		return 0;

	if (likely(opp)) {
		pstate = opp->required_opps[i]->level;
		if (pstate == OPP_LEVEL_UNSET)
			return 0;
	}

	ret = dev_pm_domain_set_performance_state(pd_dev, pstate);
	if (ret) {
		dev_err(dev, "Failed to set performance state of %s: %d (%d)\n",
			dev_name(pd_dev), pstate, ret);
	}

	return ret;
}

static int _opp_set_required_opps_generic(struct device *dev,
	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
{
	dev_err(dev, "setting required-opps isn't supported for non-genpd devices\n");
	return -ENOENT;
}

static int _opp_set_required_opps_genpd(struct device *dev,
	struct opp_table *opp_table, struct dev_pm_opp *opp, bool scaling_down)
{
	struct device **genpd_virt_devs =
		opp_table->genpd_virt_devs ? opp_table->genpd_virt_devs : &dev;
	int index, target, delta, ret;

	/* Scaling up? Set required OPPs in normal order, else reverse */
	if (!scaling_down) {
		index = 0;
		target = opp_table->required_opp_count;
		delta = 1;
	} else {
		index = opp_table->required_opp_count - 1;
		target = -1;
		delta = -1;
	}

	while (index != target) {
		ret = _set_performance_state(dev, genpd_virt_devs[index], opp, index);
		if (ret)
			return ret;

		index += delta;
	}

	return 0;
}

/* 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, bool up)
{
	/* required-opps not fully initialized yet */
	if (lazy_linking_pending(opp_table))
		return -EBUSY;

	if (opp_table->set_required_opps)
		return opp_table->set_required_opps(dev, opp_table, opp, up);

	return 0;
}

/* Update set_required_opps handler */
void _update_set_required_opps(struct opp_table *opp_table)
{
	/* Already set */
	if (opp_table->set_required_opps)
		return;

	/* All required OPPs will belong to genpd or none */
	if (opp_table->required_opp_tables[0]->is_genpd)
		opp_table->set_required_opps = _opp_set_required_opps_genpd;
	else
		opp_table->set_required_opps = _opp_set_required_opps_generic;
}

static int _set_opp_level(struct device *dev, struct opp_table *opp_table,
			  struct dev_pm_opp *opp)
{
	unsigned int level = 0;
	int ret = 0;

	if (opp) {
		if (opp->level == OPP_LEVEL_UNSET)
			return 0;

		level = opp->level;
	}

	/* Request a new performance state through the device's PM domain. */
	ret = dev_pm_domain_set_performance_state(dev, level);
	if (ret)
		dev_err(dev, "Failed to set performance state %u (%d)\n", level,
			ret);

	return ret;
}

static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
{
	struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
	unsigned long freq;

	if (!IS_ERR(opp_table->clk)) {
		freq = clk_get_rate(opp_table->clk);
		opp = _find_freq_ceil(opp_table, &freq);
	}

	/*
	 * Unable to find the current OPP ? Pick the first from the list since
	 * it is in ascending order, otherwise rest of the code will need to
	 * make special checks to validate current_opp.
	 */
	if (IS_ERR(opp)) {
		mutex_lock(&opp_table->lock);
		opp = list_first_entry(&opp_table->opp_list, struct dev_pm_opp, node);
		dev_pm_opp_get(opp);
		mutex_unlock(&opp_table->lock);
	}

	opp_table->current_opp = opp;
}

static int _disable_opp_table(struct device *dev, struct opp_table *opp_table)
{
	int ret;

	if (!opp_table->enabled)
		return 0;

	/*
	 * Some drivers need to support cases where some platforms may
	 * have OPP table for the device, while others don't and
	 * opp_set_rate() just needs to behave like clk_set_rate().
	 */
	if (!_get_opp_count(opp_table))
		return 0;

	ret = _set_opp_bw(opp_table, NULL, dev);
	if (ret)
		return ret;

	if (opp_table->regulators)
		regulator_disable(opp_table->regulators[0]);

	ret = _set_opp_level(dev, opp_table, NULL);
	if (ret)
		goto out;

	ret = _set_required_opps(dev, opp_table, NULL, false);

out:
	opp_table->enabled = false;
	return ret;
}

static int _set_opp(struct device *dev, struct opp_table *opp_table,
		    struct dev_pm_opp *opp, void *clk_data, bool forced)
{
	struct dev_pm_opp *old_opp;
	int scaling_down, ret;

	if (unlikely(!opp))
		return _disable_opp_table(dev, opp_table);

	/* Find the currently set OPP if we don't know already */
	if (unlikely(!opp_table->current_opp))
		_find_current_opp(dev, opp_table);

	old_opp = opp_table->current_opp;

	/* Return early if nothing to do */
	if (!forced && old_opp == opp && opp_table->enabled) {
		dev_dbg_ratelimited(dev, "%s: OPPs are same, nothing to do\n", __func__);
		return 0;
	}

	dev_dbg(dev, "%s: switching OPP: Freq %lu -> %lu Hz, Level %u -> %u, Bw %u -> %u\n",
		__func__, old_opp->rates[0], opp->rates[0], old_opp->level,
		opp->level, old_opp->bandwidth ? old_opp->bandwidth[0].peak : 0,
		opp->bandwidth ? opp->bandwidth[0].peak : 0);

	scaling_down = _opp_compare_key(opp_table, old_opp, opp);
	if (scaling_down == -1)
		scaling_down = 0;

	/* Scaling up? Configure required OPPs before frequency */
	if (!scaling_down) {
		ret = _set_required_opps(dev, opp_table, opp, true);
		if (ret) {
			dev_err(dev, "Failed to set required opps: %d\n", ret);
			return ret;
		}

		ret = _set_opp_level(dev, opp_table, opp);
		if (ret)
			return ret;

		ret = _set_opp_bw(opp_table, opp, dev);
		if (ret) {
			dev_err(dev, "Failed to set bw: %d\n", ret);
			return ret;
		}

		if (opp_table->config_regulators) {
			ret = opp_table->config_regulators(dev, old_opp, opp,
							   opp_table->regulators,
							   opp_table->regulator_count);
			if (ret) {
				dev_err(dev, "Failed to set regulator voltages: %d\n",
					ret);
				return ret;
			}
		}
	}

	if (opp_table->config_clks) {
		ret = opp_table->config_clks(dev, opp_table, opp, clk_data, scaling_down);
		if (ret)
			return ret;
	}

	/* Scaling down? Configure required OPPs after frequency */
	if (scaling_down) {
		if (opp_table->config_regulators) {
			ret = opp_table->config_regulators(dev, old_opp, opp,
							   opp_table->regulators,
							   opp_table->regulator_count);
			if (ret) {
				dev_err(dev, "Failed to set regulator voltages: %d\n",
					ret);
				return ret;
			}
		}

		ret = _set_opp_bw(opp_table, opp, dev);
		if (ret) {
			dev_err(dev, "Failed to set bw: %d\n", ret);
			return ret;
		}

		ret = _set_opp_level(dev, opp_table, opp);
		if (ret)
			return ret;

		ret = _set_required_opps(dev, opp_table, opp, false);
		if (ret) {
			dev_err(dev, "Failed to set required opps: %d\n", ret);
			return ret;
		}
	}

	opp_table->enabled = true;
	dev_pm_opp_put(old_opp);

	/* Make sure current_opp doesn't get freed */
	dev_pm_opp_get(opp);
	opp_table->current_opp = opp;

	return ret;
}

/**
 * dev_pm_opp_set_rate() - Configure new OPP based on frequency
 * @dev:	 device for which we do this operation
 * @target_freq: frequency to achieve
 *
 * This configures the power-supplies to the levels specified by the OPP
 * corresponding to the target_freq, and programs the clock to a value <=
 * target_freq, as rounded by clk_round_rate(). Device wanting to run at fmax
 * provided by the opp, should have already rounded to the target OPP's
 * frequency.
 */
int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
{
	struct opp_table *opp_table;
	unsigned long freq = 0, temp_freq;
	struct dev_pm_opp *opp = NULL;
	bool forced = false;
	int ret;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		dev_err(dev, "%s: device's opp table doesn't exist\n", __func__);
		return PTR_ERR(opp_table);
	}

	if (target_freq) {
		/*
		 * For IO devices which require an OPP on some platforms/SoCs
		 * while just needing to scale the clock on some others
		 * we look for empty OPP tables with just a clock handle and
		 * scale only the clk. This makes dev_pm_opp_set_rate()
		 * equivalent to a clk_set_rate()
		 */
		if (!_get_opp_count(opp_table)) {
			ret = opp_table->config_clks(dev, opp_table, NULL,
						     &target_freq, false);
			goto put_opp_table;
		}

		freq = clk_round_rate(opp_table->clk, target_freq);
		if ((long)freq <= 0)
			freq = target_freq;

		/*
		 * The clock driver may support finer resolution of the
		 * frequencies than the OPP table, don't update the frequency we
		 * pass to clk_set_rate() here.
		 */
		temp_freq = freq;
		opp = _find_freq_ceil(opp_table, &temp_freq);
		if (IS_ERR(opp)) {
			ret = PTR_ERR(opp);
			dev_err(dev, "%s: failed to find OPP for freq %lu (%d)\n",
				__func__, freq, ret);
			goto put_opp_table;
		}

		/*
		 * An OPP entry specifies the highest frequency at which other
		 * properties of the OPP entry apply. Even if the new OPP is
		 * same as the old one, we may still reach here for a different
		 * value of the frequency. In such a case, do not abort but
		 * configure the hardware to the desired frequency forcefully.
		 */
		forced = opp_table->rate_clk_single != target_freq;
	}

	ret = _set_opp(dev, opp_table, opp, &target_freq, forced);

	if (target_freq)
		dev_pm_opp_put(opp);

put_opp_table:
	dev_pm_opp_put_opp_table(opp_table);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);

/**
 * dev_pm_opp_set_opp() - Configure device for OPP
 * @dev: device for which we do this operation
 * @opp: OPP to set to
 *
 * This configures the device based on the properties of the OPP passed to this
 * routine.
 *
 * Return: 0 on success, a negative error number otherwise.
 */
int dev_pm_opp_set_opp(struct device *dev, struct dev_pm_opp *opp)
{
	struct opp_table *opp_table;
	int ret;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		dev_err(dev, "%s: device opp doesn't exist\n", __func__);
		return PTR_ERR(opp_table);
	}

	ret = _set_opp(dev, opp_table, opp, NULL, false);
	dev_pm_opp_put_opp_table(opp_table);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_set_opp);

/* OPP-dev Helpers */
static void _remove_opp_dev(struct opp_device *opp_dev,
			    struct opp_table *opp_table)
{
	opp_debug_unregister(opp_dev, opp_table);
	list_del(&opp_dev->node);
	kfree(opp_dev);
}

struct opp_device *_add_opp_dev(const struct device *dev,
				struct opp_table *opp_table)
{
	struct opp_device *opp_dev;

	opp_dev = kzalloc(sizeof(*opp_dev), GFP_KERNEL);
	if (!opp_dev)
		return NULL;

	/* Initialize opp-dev */
	opp_dev->dev = dev;

	mutex_lock(&opp_table->lock);
	list_add(&opp_dev->node, &opp_table->dev_list);
	mutex_unlock(&opp_table->lock);

	/* Create debugfs entries for the opp_table */
	opp_debug_register(opp_dev, opp_table);

	return opp_dev;
}

static struct opp_table *_allocate_opp_table(struct device *dev, int index)
{
	struct opp_table *opp_table;
	struct opp_device *opp_dev;
	int ret;

	/*
	 * Allocate a new OPP table. In the infrequent case where a new
	 * device is needed to be added, we pay this penalty.
	 */
	opp_table = kzalloc(sizeof(*opp_table), GFP_KERNEL);
	if (!opp_table)
		return ERR_PTR(-ENOMEM);

	mutex_init(&opp_table->lock);
	INIT_LIST_HEAD(&opp_table->dev_list);
	INIT_LIST_HEAD(&opp_table->lazy);

	opp_table->clk = ERR_PTR(-ENODEV);

	/* Mark regulator count uninitialized */
	opp_table->regulator_count = -1;

	opp_dev = _add_opp_dev(dev, opp_table);
	if (!opp_dev) {
		ret = -ENOMEM;
		goto err;
	}

	_of_init_opp_table(opp_table, dev, index);

	/* Find interconnect path(s) for the device */
	ret = dev_pm_opp_of_find_icc_paths(dev, opp_table);
	if (ret) {
		if (ret == -EPROBE_DEFER)
			goto remove_opp_dev;

		dev_warn(dev, "%s: Error finding interconnect paths: %d\n",
			 __func__, ret);
	}

	BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
	INIT_LIST_HEAD(&opp_table->opp_list);
	kref_init(&opp_table->kref);

	return opp_table;

remove_opp_dev:
	_of_clear_opp_table(opp_table);
	_remove_opp_dev(opp_dev, opp_table);
	mutex_destroy(&opp_table->lock);
err:
	kfree(opp_table);
	return ERR_PTR(ret);
}

void _get_opp_table_kref(struct opp_table *opp_table)
{
	kref_get(&opp_table->kref);
}

static struct opp_table *_update_opp_table_clk(struct device *dev,
					       struct opp_table *opp_table,
					       bool getclk)
{
	int ret;

	/*
	 * Return early if we don't need to get clk or we have already done it
	 * earlier.
	 */
	if (!getclk || IS_ERR(opp_table) || !IS_ERR(opp_table->clk) ||
	    opp_table->clks)
		return opp_table;

	/* Find clk for the device */
	opp_table->clk = clk_get(dev, NULL);

	ret = PTR_ERR_OR_ZERO(opp_table->clk);
	if (!ret) {
		opp_table->config_clks = _opp_config_clk_single;
		opp_table->clk_count = 1;
		return opp_table;
	}

	if (ret == -ENOENT) {
		/*
		 * There are few platforms which don't want the OPP core to
		 * manage device's clock settings. In such cases neither the
		 * platform provides the clks explicitly to us, nor the DT
		 * contains a valid clk entry. The OPP nodes in DT may still
		 * contain "opp-hz" property though, which we need to parse and
		 * allow the platform to find an OPP based on freq later on.
		 *
		 * This is a simple solution to take care of such corner cases,
		 * i.e. make the clk_count 1, which lets us allocate space for
		 * frequency in opp->rates and also parse the entries in DT.
		 */
		opp_table->clk_count = 1;

		dev_dbg(dev, "%s: Couldn't find clock: %d\n", __func__, ret);
		return opp_table;
	}

	dev_pm_opp_put_opp_table(opp_table);
	dev_err_probe(dev, ret, "Couldn't find clock\n");

	return ERR_PTR(ret);
}

/*
 * We need to make sure that the OPP table for a device doesn't get added twice,
 * if this routine gets called in parallel with the same device pointer.
 *
 * The simplest way to enforce that is to perform everything (find existing
 * table and if not found, create a new one) under the opp_table_lock, so only
 * one creator gets access to the same. But that expands the critical section
 * under the lock and may end up causing circular dependencies with frameworks
 * like debugfs, interconnect or clock framework as they may be direct or
 * indirect users of OPP core.
 *
 * And for that reason we have to go for a bit tricky implementation here, which
 * uses the opp_tables_busy flag to indicate if another creator is in the middle
 * of adding an OPP table and others should wait for it to finish.
 */
struct opp_table *_add_opp_table_indexed(struct device *dev, int index,
					 bool getclk)
{
	struct opp_table *opp_table;

again:
	mutex_lock(&opp_table_lock);

	opp_table = _find_opp_table_unlocked(dev);
	if (!IS_ERR(opp_table))
		goto unlock;

	/*
	 * The opp_tables list or an OPP table's dev_list is getting updated by
	 * another user, wait for it to finish.
	 */
	if (unlikely(opp_tables_busy)) {
		mutex_unlock(&opp_table_lock);
		cpu_relax();
		goto again;
	}

	opp_tables_busy = true;
	opp_table = _managed_opp(dev, index);

	/* Drop the lock to reduce the size of critical section */
	mutex_unlock(&opp_table_lock);

	if (opp_table) {
		if (!_add_opp_dev(dev, opp_table)) {
			dev_pm_opp_put_opp_table(opp_table);
			opp_table = ERR_PTR(-ENOMEM);
		}

		mutex_lock(&opp_table_lock);
	} else {
		opp_table = _allocate_opp_table(dev, index);

		mutex_lock(&opp_table_lock);
		if (!IS_ERR(opp_table))
			list_add(&opp_table->node, &opp_tables);
	}

	opp_tables_busy = false;

unlock:
	mutex_unlock(&opp_table_lock);

	return _update_opp_table_clk(dev, opp_table, getclk);
}

static struct opp_table *_add_opp_table(struct device *dev, bool getclk)
{
	return _add_opp_table_indexed(dev, 0, getclk);
}

struct opp_table *dev_pm_opp_get_opp_table(struct device *dev)
{
	return _find_opp_table(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_table);

static void _opp_table_kref_release(struct kref *kref)
{
	struct opp_table *opp_table = container_of(kref, struct opp_table, kref);
	struct opp_device *opp_dev, *temp;
	int i;

	/* Drop the lock as soon as we can */
	list_del(&opp_table->node);
	mutex_unlock(&opp_table_lock);

	if (opp_table->current_opp)
		dev_pm_opp_put(opp_table->current_opp);

	_of_clear_opp_table(opp_table);

	/* Release automatically acquired single clk */
	if (!IS_ERR(opp_table->clk))
		clk_put(opp_table->clk);

	if (opp_table->paths) {
		for (i = 0; i < opp_table->path_count; i++)
			icc_put(opp_table->paths[i]);
		kfree(opp_table->paths);
	}

	WARN_ON(!list_empty(&opp_table->opp_list));

	list_for_each_entry_safe(opp_dev, temp, &opp_table->dev_list, node)
		_remove_opp_dev(opp_dev, opp_table);

	mutex_destroy(&opp_table->lock);
	kfree(opp_table);
}

void dev_pm_opp_put_opp_table(struct opp_table *opp_table)
{
	kref_put_mutex(&opp_table->kref, _opp_table_kref_release,
		       &opp_table_lock);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_put_opp_table);

void _opp_free(struct dev_pm_opp *opp)
{
	kfree(opp);
}

static void _opp_kref_release(struct kref *kref)
{
	struct dev_pm_opp *opp = container_of(kref, struct dev_pm_opp, kref);
	struct opp_table *opp_table = opp->opp_table;

	list_del(&opp->node);
	mutex_unlock(&opp_table->lock);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_REMOVE, opp);
	_of_clear_opp(opp_table, opp);
	opp_debug_remove_one(opp);
	kfree(opp);
}

void dev_pm_opp_get(struct dev_pm_opp *opp)
{
	kref_get(&opp->kref);
}

void dev_pm_opp_put(struct dev_pm_opp *opp)
{
	kref_put_mutex(&opp->kref, _opp_kref_release, &opp->opp_table->lock);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_put);

/**
 * dev_pm_opp_remove()  - Remove an OPP from OPP table
 * @dev:	device for which we do this operation
 * @freq:	OPP to remove with matching 'freq'
 *
 * This function removes an opp from the opp table.
 */
void dev_pm_opp_remove(struct device *dev, unsigned long freq)
{
	struct dev_pm_opp *opp = NULL, *iter;
	struct opp_table *opp_table;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return;

	if (!assert_single_clk(opp_table))
		goto put_table;

	mutex_lock(&opp_table->lock);

	list_for_each_entry(iter, &opp_table->opp_list, node) {
		if (iter->rates[0] == freq) {
			opp = iter;
			break;
		}
	}

	mutex_unlock(&opp_table->lock);

	if (opp) {
		dev_pm_opp_put(opp);

		/* Drop the reference taken by dev_pm_opp_add() */
		dev_pm_opp_put_opp_table(opp_table);
	} else {
		dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
			 __func__, freq);
	}

put_table:
	/* Drop the reference taken by _find_opp_table() */
	dev_pm_opp_put_opp_table(opp_table);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove);

static struct dev_pm_opp *_opp_get_next(struct opp_table *opp_table,
					bool dynamic)
{
	struct dev_pm_opp *opp = NULL, *temp;

	mutex_lock(&opp_table->lock);
	list_for_each_entry(temp, &opp_table->opp_list, node) {
		/*
		 * Refcount must be dropped only once for each OPP by OPP core,
		 * do that with help of "removed" flag.
		 */
		if (!temp->removed && dynamic == temp->dynamic) {
			opp = temp;
			break;
		}
	}

	mutex_unlock(&opp_table->lock);
	return opp;
}

/*
 * Can't call dev_pm_opp_put() from under the lock as debugfs removal needs to
 * happen lock less to avoid circular dependency issues. This routine must be
 * called without the opp_table->lock held.
 */
static void _opp_remove_all(struct opp_table *opp_table, bool dynamic)
{
	struct dev_pm_opp *opp;

	while ((opp = _opp_get_next(opp_table, dynamic))) {
		opp->removed = true;
		dev_pm_opp_put(opp);

		/* Drop the references taken by dev_pm_opp_add() */
		if (dynamic)
			dev_pm_opp_put_opp_table(opp_table);
	}
}

bool _opp_remove_all_static(struct opp_table *opp_table)
{
	mutex_lock(&opp_table->lock);

	if (!opp_table->parsed_static_opps) {
		mutex_unlock(&opp_table->lock);
		return false;
	}

	if (--opp_table->parsed_static_opps) {
		mutex_unlock(&opp_table->lock);
		return true;
	}

	mutex_unlock(&opp_table->lock);

	_opp_remove_all(opp_table, false);
	return true;
}

/**
 * dev_pm_opp_remove_all_dynamic() - Remove all dynamically created OPPs
 * @dev:	device for which we do this operation
 *
 * This function removes all dynamically created OPPs from the opp table.
 */
void dev_pm_opp_remove_all_dynamic(struct device *dev)
{
	struct opp_table *opp_table;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return;

	_opp_remove_all(opp_table, true);

	/* Drop the reference taken by _find_opp_table() */
	dev_pm_opp_put_opp_table(opp_table);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove_all_dynamic);

struct dev_pm_opp *_opp_allocate(struct opp_table *opp_table)
{
	struct dev_pm_opp *opp;
	int supply_count, supply_size, icc_size, clk_size;

	/* Allocate space for at least one supply */
	supply_count = opp_table->regulator_count > 0 ?
			opp_table->regulator_count : 1;
	supply_size = sizeof(*opp->supplies) * supply_count;
	clk_size = sizeof(*opp->rates) * opp_table->clk_count;
	icc_size = sizeof(*opp->bandwidth) * opp_table->path_count;

	/* allocate new OPP node and supplies structures */
	opp = kzalloc(sizeof(*opp) + supply_size + clk_size + icc_size, GFP_KERNEL);
	if (!opp)
		return NULL;

	/* Put the supplies, bw and clock at the end of the OPP structure */
	opp->supplies = (struct dev_pm_opp_supply *)(opp + 1);

	opp->rates = (unsigned long *)(opp->supplies + supply_count);

	if (icc_size)
		opp->bandwidth = (struct dev_pm_opp_icc_bw *)(opp->rates + opp_table->clk_count);

	INIT_LIST_HEAD(&opp->node);

	opp->level = OPP_LEVEL_UNSET;

	return opp;
}

static bool _opp_supported_by_regulators(struct dev_pm_opp *opp,
					 struct opp_table *opp_table)
{
	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];

		if (!regulator_is_supported_voltage(reg,
					opp->supplies[i].u_volt_min,
					opp->supplies[i].u_volt_max)) {
			pr_warn("%s: OPP minuV: %lu maxuV: %lu, not supported by regulator\n",
				__func__, opp->supplies[i].u_volt_min,
				opp->supplies[i].u_volt_max);
			return false;
		}
	}

	return true;
}

static int _opp_compare_rate(struct opp_table *opp_table,
			     struct dev_pm_opp *opp1, struct dev_pm_opp *opp2)
{
	int i;

	for (i = 0; i < opp_table->clk_count; i++) {
		if (opp1->rates[i] != opp2->rates[i])
			return opp1->rates[i] < opp2->rates[i] ? -1 : 1;
	}

	/* Same rates for both OPPs */
	return 0;
}

static int _opp_compare_bw(struct opp_table *opp_table, struct dev_pm_opp *opp1,
			   struct dev_pm_opp *opp2)
{
	int i;

	for (i = 0; i < opp_table->path_count; i++) {
		if (opp1->bandwidth[i].peak != opp2->bandwidth[i].peak)
			return opp1->bandwidth[i].peak < opp2->bandwidth[i].peak ? -1 : 1;
	}

	/* Same bw for both OPPs */
	return 0;
}

/*
 * Returns
 * 0: opp1 == opp2
 * 1: opp1 > opp2
 * -1: opp1 < opp2
 */
int _opp_compare_key(struct opp_table *opp_table, struct dev_pm_opp *opp1,
		     struct dev_pm_opp *opp2)
{
	int ret;

	ret = _opp_compare_rate(opp_table, opp1, opp2);
	if (ret)
		return ret;

	ret = _opp_compare_bw(opp_table, opp1, opp2);
	if (ret)
		return ret;

	if (opp1->level != opp2->level)
		return opp1->level < opp2->level ? -1 : 1;

	/* Duplicate OPPs */
	return 0;
}

static int _opp_is_duplicate(struct device *dev, struct dev_pm_opp *new_opp,
			     struct opp_table *opp_table,
			     struct list_head **head)
{
	struct dev_pm_opp *opp;
	int opp_cmp;

	/*
	 * Insert new OPP in order of increasing frequency and discard if
	 * already present.
	 *
	 * Need to use &opp_table->opp_list in the condition part of the 'for'
	 * loop, don't replace it with head otherwise it will become an infinite
	 * loop.
	 */
	list_for_each_entry(opp, &opp_table->opp_list, node) {
		opp_cmp = _opp_compare_key(opp_table, new_opp, opp);
		if (opp_cmp > 0) {
			*head = &opp->node;
			continue;
		}

		if (opp_cmp < 0)
			return 0;

		/* Duplicate OPPs */
		dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
			 __func__, opp->rates[0], opp->supplies[0].u_volt,
			 opp->available, new_opp->rates[0],
			 new_opp->supplies[0].u_volt, new_opp->available);

		/* Should we compare voltages for all regulators here ? */
		return opp->available &&
		       new_opp->supplies[0].u_volt == opp->supplies[0].u_volt ? -EBUSY : -EEXIST;
	}

	return 0;
}

void _required_opps_available(struct dev_pm_opp *opp, int count)
{
	int i;

	for (i = 0; i < count; i++) {
		if (opp->required_opps[i]->available)
			continue;

		opp->available = false;
		pr_warn("%s: OPP not supported by required OPP %pOF (%lu)\n",
			 __func__, opp->required_opps[i]->np, opp->rates[0]);
		return;
	}
}

/*
 * Returns:
 * 0: On success. And appropriate error message for duplicate OPPs.
 * -EBUSY: For OPP with same freq/volt and is available. The callers of
 *  _opp_add() must return 0 if they receive -EBUSY from it. This is to make
 *  sure we don't print error messages unnecessarily if different parts of
 *  kernel try to initialize the OPP table.
 * -EEXIST: For OPP with same freq but different volt or is unavailable. This
 *  should be considered an error by the callers of _opp_add().
 */
int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
	     struct opp_table *opp_table)
{
	struct list_head *head;
	int ret;

	mutex_lock(&opp_table->lock);
	head = &opp_table->opp_list;

	ret = _opp_is_duplicate(dev, new_opp, opp_table, &head);
	if (ret) {
		mutex_unlock(&opp_table->lock);
		return ret;
	}

	list_add(&new_opp->node, head);
	mutex_unlock(&opp_table->lock);

	new_opp->opp_table = opp_table;
	kref_init(&new_opp->kref);

	opp_debug_create_one(new_opp, opp_table);

	if (!_opp_supported_by_regulators(new_opp, opp_table)) {
		new_opp->available = false;
		dev_warn(dev, "%s: OPP not supported by regulators (%lu)\n",
			 __func__, new_opp->rates[0]);
	}

	/* required-opps not fully initialized yet */
	if (lazy_linking_pending(opp_table))
		return 0;

	_required_opps_available(new_opp, opp_table->required_opp_count);

	return 0;
}

/**
 * _opp_add_v1() - Allocate a OPP based on v1 bindings.
 * @opp_table:	OPP table
 * @dev:	device for which we do this operation
 * @data:	The OPP data for the OPP to add
 * @dynamic:	Dynamically added OPPs.
 *
 * This function adds an opp definition to the opp table and returns status.
 * The opp is made available by default and it can be controlled using
 * dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
 *
 * NOTE: "dynamic" parameter impacts OPPs added by the dev_pm_opp_of_add_table
 * and freed by dev_pm_opp_of_remove_table.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 */
int _opp_add_v1(struct opp_table *opp_table, struct device *dev,
		struct dev_pm_opp_data *data, bool dynamic)
{
	struct dev_pm_opp *new_opp;
	unsigned long tol, u_volt = data->u_volt;
	int ret;

	if (!assert_single_clk(opp_table))
		return -EINVAL;

	new_opp = _opp_allocate(opp_table);
	if (!new_opp)
		return -ENOMEM;

	/* populate the opp table */
	new_opp->rates[0] = data->freq;
	new_opp->level = data->level;
	tol = u_volt * opp_table->voltage_tolerance_v1 / 100;
	new_opp->supplies[0].u_volt = u_volt;
	new_opp->supplies[0].u_volt_min = u_volt - tol;
	new_opp->supplies[0].u_volt_max = u_volt + tol;
	new_opp->available = true;
	new_opp->dynamic = dynamic;

	ret = _opp_add(dev, new_opp, opp_table);
	if (ret) {
		/* Don't return error for duplicate OPPs */
		if (ret == -EBUSY)
			ret = 0;
		goto free_opp;
	}

	/*
	 * 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 0;

free_opp:
	_opp_free(new_opp);

	return ret;
}

/*
 * This is required only for the V2 bindings, and it enables a platform to
 * specify the hierarchy of versions it supports. OPP layer will then enable
 * OPPs, which are available for those versions, based on its 'opp-supported-hw'
 * property.
 */
static int _opp_set_supported_hw(struct opp_table *opp_table,
				 const u32 *versions, unsigned int count)
{
	/* Another CPU that shares the OPP table has set the property ? */
	if (opp_table->supported_hw)
		return 0;

	opp_table->supported_hw = kmemdup(versions, count * sizeof(*versions),
					GFP_KERNEL);
	if (!opp_table->supported_hw)
		return -ENOMEM;

	opp_table->supported_hw_count = count;

	return 0;
}

static void _opp_put_supported_hw(struct opp_table *opp_table)
{
	if (opp_table->supported_hw) {
		kfree(opp_table->supported_hw);
		opp_table->supported_hw = NULL;
		opp_table->supported_hw_count = 0;
	}
}

/*
 * This is required only for the V2 bindings, and it enables a platform to
 * specify the extn to be used for certain property names. The properties to
 * which the extension will apply are opp-microvolt and opp-microamp. OPP core
 * should postfix the property name with -<name> while looking for them.
 */
static int _opp_set_prop_name(struct opp_table *opp_table, const char *name)
{
	/* Another CPU that shares the OPP table has set the property ? */
	if (!opp_table->prop_name) {
		opp_table->prop_name = kstrdup(name, GFP_KERNEL);
		if (!opp_table->prop_name)
			return -ENOMEM;
	}

	return 0;
}

static void _opp_put_prop_name(struct opp_table *opp_table)
{
	if (opp_table->prop_name) {
		kfree(opp_table->prop_name);
		opp_table->prop_name = NULL;
	}
}

/*
 * In order to support OPP switching, OPP layer needs to know the name of the
 * device's regulators, as the core would be required to switch voltages as
 * well.
 *
 * This must be called before any OPPs are initialized for the device.
 */
static int _opp_set_regulators(struct opp_table *opp_table, struct device *dev,
			       const char * const names[])
{
	const char * const *temp = names;
	struct regulator *reg;
	int count = 0, ret, i;

	/* Count number of regulators */
	while (*temp++)
		count++;

	if (!count)
		return -EINVAL;

	/* Another CPU that shares the OPP table has set the regulators ? */
	if (opp_table->regulators)
		return 0;

	opp_table->regulators = kmalloc_array(count,
					      sizeof(*opp_table->regulators),
					      GFP_KERNEL);
	if (!opp_table->regulators)
		return -ENOMEM;

	for (i = 0; i < count; i++) {
		reg = regulator_get_optional(dev, names[i]);
		if (IS_ERR(reg)) {
			ret = dev_err_probe(dev, PTR_ERR(reg),
					    "%s: no regulator (%s) found\n",
					    __func__, names[i]);
			goto free_regulators;
		}

		opp_table->regulators[i] = reg;
	}

	opp_table->regulator_count = count;

	/* Set generic config_regulators() for single regulators here */
	if (count == 1)
		opp_table->config_regulators = _opp_config_regulator_single;

	return 0;

free_regulators:
	while (i != 0)
		regulator_put(opp_table->regulators[--i]);

	kfree(opp_table->regulators);
	opp_table->regulators = NULL;
	opp_table->regulator_count = -1;

	return ret;
}

static void _opp_put_regulators(struct opp_table *opp_table)
{
	int i;

	if (!opp_table->regulators)
		return;

	if (opp_table->enabled) {
		for (i = opp_table->regulator_count - 1; i >= 0; i--)
			regulator_disable(opp_table->regulators[i]);
	}

	for (i = opp_table->regulator_count - 1; i >= 0; i--)
		regulator_put(opp_table->regulators[i]);

	kfree(opp_table->regulators);
	opp_table->regulators = NULL;
	opp_table->regulator_count = -1;
}

static void _put_clks(struct opp_table *opp_table, int count)
{
	int i;

	for (i = count - 1; i >= 0; i--)
		clk_put(opp_table->clks[i]);

	kfree(opp_table->clks);
	opp_table->clks = NULL;
}

/*
 * In order to support OPP switching, OPP layer needs to get pointers to the
 * clocks for the device. Simple cases work fine without using this routine
 * (i.e. by passing connection-id as NULL), but for a device with multiple
 * clocks available, the OPP core needs to know the exact names of the clks to
 * use.
 *
 * This must be called before any OPPs are initialized for the device.
 */
static int _opp_set_clknames(struct opp_table *opp_table, struct device *dev,
			     const char * const names[],
			     config_clks_t config_clks)
{
	const char * const *temp = names;
	int count = 0, ret, i;
	struct clk *clk;

	/* Count number of clks */
	while (*temp++)
		count++;

	/*
	 * This is a special case where we have a single clock, whose connection
	 * id name is NULL, i.e. first two entries are NULL in the array.
	 */
	if (!count && !names[1])
		count = 1;

	/* Fail early for invalid configurations */
	if (!count || (!config_clks && count > 1))
		return -EINVAL;

	/* Another CPU that shares the OPP table has set the clkname ? */
	if (opp_table->clks)
		return 0;

	opp_table->clks = kmalloc_array(count, sizeof(*opp_table->clks),
					GFP_KERNEL);
	if (!opp_table->clks)
		return -ENOMEM;

	/* Find clks for the device */
	for (i = 0; i < count; i++) {
		clk = clk_get(dev, names[i]);
		if (IS_ERR(clk)) {
			ret = dev_err_probe(dev, PTR_ERR(clk),
					    "%s: Couldn't find clock with name: %s\n",
					    __func__, names[i]);
			goto free_clks;
		}

		opp_table->clks[i] = clk;
	}

	opp_table->clk_count = count;
	opp_table->config_clks = config_clks;

	/* Set generic single clk set here */
	if (count == 1) {
		if (!opp_table->config_clks)
			opp_table->config_clks = _opp_config_clk_single;

		/*
		 * We could have just dropped the "clk" field and used "clks"
		 * everywhere. Instead we kept the "clk" field around for
		 * following reasons:
		 *
		 * - avoiding clks[0] everywhere else.
		 * - not running single clk helpers for multiple clk usecase by
		 *   mistake.
		 *
		 * Since this is single-clk case, just update the clk pointer
		 * too.
		 */
		opp_table->clk = opp_table->clks[0];
	}

	return 0;

free_clks:
	_put_clks(opp_table, i);
	return ret;
}

static void _opp_put_clknames(struct opp_table *opp_table)
{
	if (!opp_table->clks)
		return;

	opp_table->config_clks = NULL;
	opp_table->clk = ERR_PTR(-ENODEV);

	_put_clks(opp_table, opp_table->clk_count);
}

/*
 * This is useful to support platforms with multiple regulators per device.
 *
 * This must be called before any OPPs are initialized for the device.
 */
static int _opp_set_config_regulators_helper(struct opp_table *opp_table,
		struct device *dev, config_regulators_t config_regulators)
{
	/* Another CPU that shares the OPP table has set the helper ? */
	if (!opp_table->config_regulators)
		opp_table->config_regulators = config_regulators;

	return 0;
}

static void _opp_put_config_regulators_helper(struct opp_table *opp_table)
{
	if (opp_table->config_regulators)
		opp_table->config_regulators = NULL;
}

static void _opp_detach_genpd(struct opp_table *opp_table)
{
	int index;

	if (!opp_table->genpd_virt_devs)
		return;

	for (index = 0; index < opp_table->required_opp_count; index++) {
		if (!opp_table->genpd_virt_devs[index])
			continue;

		dev_pm_domain_detach(opp_table->genpd_virt_devs[index], false);
		opp_table->genpd_virt_devs[index] = NULL;
	}

	kfree(opp_table->genpd_virt_devs);
	opp_table->genpd_virt_devs = NULL;
}

/*
 * 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.
 * The same API also works for the case where single genpd is available and so
 * we don't need to support that separately.
 *
 * This helper will normally be called by the consumer driver of the device
 * "dev", as only that has details of the genpd names.
 *
 * This helper needs to be called once with a list of all genpd to attach.
 * Otherwise the original device structure will be used instead by the OPP core.
 *
 * The order of entries in the names array must match the order in which
 * "required-opps" are added in DT.
 */
static int _opp_attach_genpd(struct opp_table *opp_table, struct device *dev,
			const char * const *names, struct device ***virt_devs)
{
	struct device *virt_dev;
	int index = 0, ret = -EINVAL;
	const char * const *name = names;

	if (opp_table->genpd_virt_devs)
		return 0;

	opp_table->genpd_virt_devs = kcalloc(opp_table->required_opp_count,
					     sizeof(*opp_table->genpd_virt_devs),
					     GFP_KERNEL);
	if (!opp_table->genpd_virt_devs)
		return -ENOMEM;

	while (*name) {
		if (index >= opp_table->required_opp_count) {
			dev_err(dev, "Index can't be greater than required-opp-count - 1, %s (%d : %d)\n",
				*name, opp_table->required_opp_count, index);
			goto err;
		}

		virt_dev = dev_pm_domain_attach_by_name(dev, *name);
		if (IS_ERR_OR_NULL(virt_dev)) {
			ret = virt_dev ? PTR_ERR(virt_dev) : -ENODEV;
			dev_err(dev, "Couldn't attach to pm_domain: %d\n", ret);
			goto err;
		}

		opp_table->genpd_virt_devs[index] = virt_dev;
		index++;
		name++;
	}

	if (virt_devs)
		*virt_devs = opp_table->genpd_virt_devs;

	return 0;

err:
	_opp_detach_genpd(opp_table);
	return ret;

}

static void _opp_clear_config(struct opp_config_data *data)
{
	if (data->flags & OPP_CONFIG_GENPD)
		_opp_detach_genpd(data->opp_table);
	if (data->flags & OPP_CONFIG_REGULATOR)
		_opp_put_regulators(data->opp_table);
	if (data->flags & OPP_CONFIG_SUPPORTED_HW)
		_opp_put_supported_hw(data->opp_table);
	if (data->flags & OPP_CONFIG_REGULATOR_HELPER)
		_opp_put_config_regulators_helper(data->opp_table);
	if (data->flags & OPP_CONFIG_PROP_NAME)
		_opp_put_prop_name(data->opp_table);
	if (data->flags & OPP_CONFIG_CLK)
		_opp_put_clknames(data->opp_table);

	dev_pm_opp_put_opp_table(data->opp_table);
	kfree(data);
}

/**
 * dev_pm_opp_set_config() - Set OPP configuration for the device.
 * @dev: Device for which configuration is being set.
 * @config: OPP configuration.
 *
 * This allows all device OPP configurations to be performed at once.
 *
 * This must be called before any OPPs are initialized for the device. This may
 * be called multiple times for the same OPP table, for example once for each
 * CPU that share the same table. This must be balanced by the same number of
 * calls to dev_pm_opp_clear_config() in order to free the OPP table properly.
 *
 * This returns a token to the caller, which must be passed to
 * dev_pm_opp_clear_config() to free the resources later. The value of the
 * returned token will be >= 1 for success and negative for errors. The minimum
 * value of 1 is chosen here to make it easy for callers to manage the resource.
 */
int dev_pm_opp_set_config(struct device *dev, struct dev_pm_opp_config *config)
{
	struct opp_table *opp_table;
	struct opp_config_data *data;
	unsigned int id;
	int ret;

	data = kmalloc(sizeof(*data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	opp_table = _add_opp_table(dev, false);
	if (IS_ERR(opp_table)) {
		kfree(data);
		return PTR_ERR(opp_table);
	}

	data->opp_table = opp_table;
	data->flags = 0;

	/* This should be called before OPPs are initialized */
	if (WARN_ON(!list_empty(&opp_table->opp_list))) {
		ret = -EBUSY;
		goto err;
	}

	/* Configure clocks */
	if (config->clk_names) {
		ret = _opp_set_clknames(opp_table, dev, config->clk_names,
					config->config_clks);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_CLK;
	} else if (config->config_clks) {
		/* Don't allow config callback without clocks */
		ret = -EINVAL;
		goto err;
	}

	/* Configure property names */
	if (config->prop_name) {
		ret = _opp_set_prop_name(opp_table, config->prop_name);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_PROP_NAME;
	}

	/* Configure config_regulators helper */
	if (config->config_regulators) {
		ret = _opp_set_config_regulators_helper(opp_table, dev,
						config->config_regulators);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_REGULATOR_HELPER;
	}

	/* Configure supported hardware */
	if (config->supported_hw) {
		ret = _opp_set_supported_hw(opp_table, config->supported_hw,
					    config->supported_hw_count);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_SUPPORTED_HW;
	}

	/* Configure supplies */
	if (config->regulator_names) {
		ret = _opp_set_regulators(opp_table, dev,
					  config->regulator_names);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_REGULATOR;
	}

	/* Attach genpds */
	if (config->genpd_names) {
		ret = _opp_attach_genpd(opp_table, dev, config->genpd_names,
					config->virt_devs);
		if (ret)
			goto err;

		data->flags |= OPP_CONFIG_GENPD;
	}

	ret = xa_alloc(&opp_configs, &id, data, XA_LIMIT(1, INT_MAX),
		       GFP_KERNEL);
	if (ret)
		goto err;

	return id;

err:
	_opp_clear_config(data);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_set_config);

/**
 * dev_pm_opp_clear_config() - Releases resources blocked for OPP configuration.
 * @token: The token returned by dev_pm_opp_set_config() previously.
 *
 * This allows all device OPP configurations to be cleared at once. This must be
 * called once for each call made to dev_pm_opp_set_config(), in order to free
 * the OPPs properly.
 *
 * Currently the first call itself ends up freeing all the OPP configurations,
 * while the later ones only drop the OPP table reference. This works well for
 * now as we would never want to use an half initialized OPP table and want to
 * remove the configurations together.
 */
void dev_pm_opp_clear_config(int token)
{
	struct opp_config_data *data;

	/*
	 * This lets the callers call this unconditionally and keep their code
	 * simple.
	 */
	if (unlikely(token <= 0))
		return;

	data = xa_erase(&opp_configs, token);
	if (WARN_ON(!data))
		return;

	_opp_clear_config(data);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_clear_config);

static void devm_pm_opp_config_release(void *token)
{
	dev_pm_opp_clear_config((unsigned long)token);
}

/**
 * devm_pm_opp_set_config() - Set OPP configuration for the device.
 * @dev: Device for which configuration is being set.
 * @config: OPP configuration.
 *
 * This allows all device OPP configurations to be performed at once.
 * This is a resource-managed variant of dev_pm_opp_set_config().
 *
 * Return: 0 on success and errorno otherwise.
 */
int devm_pm_opp_set_config(struct device *dev, struct dev_pm_opp_config *config)
{
	int token = dev_pm_opp_set_config(dev, config);

	if (token < 0)
		return token;

	return devm_add_action_or_reset(dev, devm_pm_opp_config_release,
					(void *) ((unsigned long) token));
}
EXPORT_SYMBOL_GPL(devm_pm_opp_set_config);

/**
 * dev_pm_opp_xlate_required_opp() - Find required OPP for @src_table OPP.
 * @src_table: OPP table which has @dst_table as one of its required OPP table.
 * @dst_table: Required OPP table of the @src_table.
 * @src_opp: OPP from the @src_table.
 *
 * This function returns the OPP (present in @dst_table) pointed out by the
 * "required-opps" property of the @src_opp (present in @src_table).
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 *
 * Return: pointer to 'struct dev_pm_opp' on success and errorno otherwise.
 */
struct dev_pm_opp *dev_pm_opp_xlate_required_opp(struct opp_table *src_table,
						 struct opp_table *dst_table,
						 struct dev_pm_opp *src_opp)
{
	struct dev_pm_opp *opp, *dest_opp = ERR_PTR(-ENODEV);
	int i;

	if (!src_table || !dst_table || !src_opp ||
	    !src_table->required_opp_tables)
		return ERR_PTR(-EINVAL);

	/* required-opps not fully initialized yet */
	if (lazy_linking_pending(src_table))
		return ERR_PTR(-EBUSY);

	for (i = 0; i < src_table->required_opp_count; i++) {
		if (src_table->required_opp_tables[i] == dst_table) {
			mutex_lock(&src_table->lock);

			list_for_each_entry(opp, &src_table->opp_list, node) {
				if (opp == src_opp) {
					dest_opp = opp->required_opps[i];
					dev_pm_opp_get(dest_opp);
					break;
				}
			}

			mutex_unlock(&src_table->lock);
			break;
		}
	}

	if (IS_ERR(dest_opp)) {
		pr_err("%s: Couldn't find matching OPP (%p: %p)\n", __func__,
		       src_table, dst_table);
	}

	return dest_opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_xlate_required_opp);

/**
 * 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;

	/*
	 * 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 || !src_table->required_opp_count)
		return pstate;

	/* Both OPP tables must belong to genpds */
	if (unlikely(!src_table->is_genpd || !dst_table->is_genpd)) {
		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
		return -EINVAL;
	}

	/* required-opps not fully initialized yet */
	if (lazy_linking_pending(src_table))
		return -EBUSY;

	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->level == pstate) {
			dest_pstate = opp->required_opps[i]->level;
			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_dynamic()  - Add an OPP table from a table definitions
 * @dev:	The device for which we do this operation
 * @data:	The OPP data for the OPP to add
 *
 * This function adds an opp definition to the opp table and returns status.
 * The opp is made available by default and it can be controlled using
 * dev_pm_opp_enable/disable functions.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 */
int dev_pm_opp_add_dynamic(struct device *dev, struct dev_pm_opp_data *data)
{
	struct opp_table *opp_table;
	int ret;

	opp_table = _add_opp_table(dev, true);
	if (IS_ERR(opp_table))
		return PTR_ERR(opp_table);

	/* Fix regulator count for dynamic OPPs */
	opp_table->regulator_count = 1;

	ret = _opp_add_v1(opp_table, dev, data, true);
	if (ret)
		dev_pm_opp_put_opp_table(opp_table);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add_dynamic);

/**
 * _opp_set_availability() - helper to set the availability of an opp
 * @dev:		device for which we do this operation
 * @freq:		OPP frequency to modify availability
 * @availability_req:	availability status requested for this opp
 *
 * Set the availability of an OPP, opp_{enable,disable} share a common logic
 * which is isolated here.
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 */
static int _opp_set_availability(struct device *dev, unsigned long freq,
				 bool availability_req)
{
	struct opp_table *opp_table;
	struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV);
	int r = 0;

	/* Find the opp_table */
	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		r = PTR_ERR(opp_table);
		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
		return r;
	}

	if (!assert_single_clk(opp_table)) {
		r = -EINVAL;
		goto put_table;
	}

	mutex_lock(&opp_table->lock);

	/* Do we have the frequency? */
	list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
		if (tmp_opp->rates[0] == freq) {
			opp = tmp_opp;
			break;
		}
	}

	if (IS_ERR(opp)) {
		r = PTR_ERR(opp);
		goto unlock;
	}

	/* Is update really needed? */
	if (opp->available == availability_req)
		goto unlock;

	opp->available = availability_req;

	dev_pm_opp_get(opp);
	mutex_unlock(&opp_table->lock);

	/* Notify the change of the OPP availability */
	if (availability_req)
		blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ENABLE,
					     opp);
	else
		blocking_notifier_call_chain(&opp_table->head,
					     OPP_EVENT_DISABLE, opp);

	dev_pm_opp_put(opp);
	goto put_table;

unlock:
	mutex_unlock(&opp_table->lock);
put_table:
	dev_pm_opp_put_opp_table(opp_table);
	return r;
}

/**
 * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP
 * @dev:		device for which we do this operation
 * @freq:		OPP frequency to adjust voltage of
 * @u_volt:		new OPP target voltage
 * @u_volt_min:		new OPP min voltage
 * @u_volt_max:		new OPP max voltage
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modifcation was done OR modification was
 * successful.
 */
int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
			      unsigned long u_volt, unsigned long u_volt_min,
			      unsigned long u_volt_max)

{
	struct opp_table *opp_table;
	struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV);
	int r = 0;

	/* Find the opp_table */
	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		r = PTR_ERR(opp_table);
		dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
		return r;
	}

	if (!assert_single_clk(opp_table)) {
		r = -EINVAL;
		goto put_table;
	}

	mutex_lock(&opp_table->lock);

	/* Do we have the frequency? */
	list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
		if (tmp_opp->rates[0] == freq) {
			opp = tmp_opp;
			break;
		}
	}

	if (IS_ERR(opp)) {
		r = PTR_ERR(opp);
		goto adjust_unlock;
	}

	/* Is update really needed? */
	if (opp->supplies->u_volt == u_volt)
		goto adjust_unlock;

	opp->supplies->u_volt = u_volt;
	opp->supplies->u_volt_min = u_volt_min;
	opp->supplies->u_volt_max = u_volt_max;

	dev_pm_opp_get(opp);
	mutex_unlock(&opp_table->lock);

	/* Notify the voltage change of the OPP */
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE,
				     opp);

	dev_pm_opp_put(opp);
	goto put_table;

adjust_unlock:
	mutex_unlock(&opp_table->lock);
put_table:
	dev_pm_opp_put_opp_table(opp_table);
	return r;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_adjust_voltage);

/**
 * dev_pm_opp_enable() - Enable a specific OPP
 * @dev:	device for which we do this operation
 * @freq:	OPP frequency to enable
 *
 * Enables a provided opp. If the operation is valid, this returns 0, else the
 * corresponding error value. It is meant to be used for users an OPP available
 * after being temporarily made unavailable with dev_pm_opp_disable.
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 */
int dev_pm_opp_enable(struct device *dev, unsigned long freq)
{
	return _opp_set_availability(dev, freq, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_enable);

/**
 * dev_pm_opp_disable() - Disable a specific OPP
 * @dev:	device for which we do this operation
 * @freq:	OPP frequency to disable
 *
 * Disables a provided opp. If the operation is valid, this returns
 * 0, else the corresponding error value. It is meant to be a temporary
 * control by users to make this OPP not available until the circumstances are
 * right to make it available again (with a call to dev_pm_opp_enable).
 *
 * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
 * copy operation, returns 0 if no modification was done OR modification was
 * successful.
 */
int dev_pm_opp_disable(struct device *dev, unsigned long freq)
{
	return _opp_set_availability(dev, freq, false);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_disable);

/**
 * dev_pm_opp_register_notifier() - Register OPP notifier for the device
 * @dev:	Device for which notifier needs to be registered
 * @nb:		Notifier block to be registered
 *
 * Return: 0 on success or a negative error value.
 */
int dev_pm_opp_register_notifier(struct device *dev, struct notifier_block *nb)
{
	struct opp_table *opp_table;
	int ret;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return PTR_ERR(opp_table);

	ret = blocking_notifier_chain_register(&opp_table->head, nb);

	dev_pm_opp_put_opp_table(opp_table);

	return ret;
}
EXPORT_SYMBOL(dev_pm_opp_register_notifier);

/**
 * dev_pm_opp_unregister_notifier() - Unregister OPP notifier for the device
 * @dev:	Device for which notifier needs to be unregistered
 * @nb:		Notifier block to be unregistered
 *
 * Return: 0 on success or a negative error value.
 */
int dev_pm_opp_unregister_notifier(struct device *dev,
				   struct notifier_block *nb)
{
	struct opp_table *opp_table;
	int ret;

	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return PTR_ERR(opp_table);

	ret = blocking_notifier_chain_unregister(&opp_table->head, nb);

	dev_pm_opp_put_opp_table(opp_table);

	return ret;
}
EXPORT_SYMBOL(dev_pm_opp_unregister_notifier);

/**
 * dev_pm_opp_remove_table() - Free all OPPs associated with the device
 * @dev:	device pointer used to lookup OPP table.
 *
 * Free both OPPs created using static entries present in DT and the
 * dynamically added entries.
 */
void dev_pm_opp_remove_table(struct device *dev)
{
	struct opp_table *opp_table;

	/* Check for existing table for 'dev' */
	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table)) {
		int error = PTR_ERR(opp_table);

		if (error != -ENODEV)
			WARN(1, "%s: opp_table: %d\n",
			     IS_ERR_OR_NULL(dev) ?
					"Invalid device" : dev_name(dev),
			     error);
		return;
	}

	/*
	 * Drop the extra reference only if the OPP table was successfully added
	 * with dev_pm_opp_of_add_table() earlier.
	 **/
	if (_opp_remove_all_static(opp_table))
		dev_pm_opp_put_opp_table(opp_table);

	/* Drop reference taken by _find_opp_table() */
	dev_pm_opp_put_opp_table(opp_table);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove_table);

/**
 * dev_pm_opp_sync_regulators() - Sync state of voltage regulators
 * @dev:	device for which we do this operation
 *
 * Sync voltage state of the OPP table regulators.
 *
 * Return: 0 on success or a negative error value.
 */
int dev_pm_opp_sync_regulators(struct device *dev)
{
	struct opp_table *opp_table;
	struct regulator *reg;
	int i, ret = 0;

	/* Device may not have OPP table */
	opp_table = _find_opp_table(dev);
	if (IS_ERR(opp_table))
		return 0;

	/* Regulator may not be required for the device */
	if (unlikely(!opp_table->regulators))
		goto put_table;

	/* Nothing to sync if voltage wasn't changed */
	if (!opp_table->enabled)
		goto put_table;

	for (i = 0; i < opp_table->regulator_count; i++) {
		reg = opp_table->regulators[i];
		ret = regulator_sync_voltage(reg);
		if (ret)
			break;
	}
put_table:
	/* Drop reference taken by _find_opp_table() */
	dev_pm_opp_put_opp_table(opp_table);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_sync_regulators);