[linux-2.6-block.git] / drivers / base / power / opp / cpu.c

/*
 * Generic OPP helper interface for CPU device
 *
 * Copyright (C) 2009-2014 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/slab.h>

#include "opp.h"

#ifdef CONFIG_CPU_FREQ

/**
 * dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
 * @dev:	device for which we do this operation
 * @table:	Cpufreq table returned back to caller
 *
 * Generate a cpufreq table for a provided device- this assumes that the
 * opp table is already initialized and ready for usage.
 *
 * This function allocates required memory for the cpufreq table. It is
 * expected that the caller does the required maintenance such as freeing
 * the table as required.
 *
 * Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
 * if no memory available for the operation (table is not populated), returns 0
 * if successful and table is populated.
 *
 * WARNING: It is  important for the callers to ensure refreshing their copy of
 * the table if any of the mentioned functions have been invoked in the interim.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Since we just use the regular accessor functions to access the internal data
 * structures, we use RCU read lock inside this function. As a result, users of
 * this function DONOT need to use explicit locks for invoking.
 */
int dev_pm_opp_init_cpufreq_table(struct device *dev,
				  struct cpufreq_frequency_table **table)
{
	struct dev_pm_opp *opp;
	struct cpufreq_frequency_table *freq_table = NULL;
	int i, max_opps, ret = 0;
	unsigned long rate;

	rcu_read_lock();

	max_opps = dev_pm_opp_get_opp_count(dev);
	if (max_opps <= 0) {
		ret = max_opps ? max_opps : -ENODATA;
		goto out;
	}

	freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
	if (!freq_table) {
		ret = -ENOMEM;
		goto out;
	}

	for (i = 0, rate = 0; i < max_opps; i++, rate++) {
		/* find next rate */
		opp = dev_pm_opp_find_freq_ceil(dev, &rate);
		if (IS_ERR(opp)) {
			ret = PTR_ERR(opp);
			goto out;
		}
		freq_table[i].driver_data = i;
		freq_table[i].frequency = rate / 1000;

		/* Is Boost/turbo opp ? */
		if (dev_pm_opp_is_turbo(opp))
			freq_table[i].flags = CPUFREQ_BOOST_FREQ;
	}

	freq_table[i].driver_data = i;
	freq_table[i].frequency = CPUFREQ_TABLE_END;

	*table = &freq_table[0];

out:
	rcu_read_unlock();
	if (ret)
		kfree(freq_table);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);

/**
 * dev_pm_opp_free_cpufreq_table() - free the cpufreq table
 * @dev:	device for which we do this operation
 * @table:	table to free
 *
 * Free up the table allocated by dev_pm_opp_init_cpufreq_table
 */
void dev_pm_opp_free_cpufreq_table(struct device *dev,
				   struct cpufreq_frequency_table **table)
{
	if (!table)
		return;

	kfree(*table);
	*table = NULL;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
#endif	/* CONFIG_CPU_FREQ */

#ifdef CONFIG_OF
/**
 * 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.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
void dev_pm_opp_of_cpumask_remove_table(cpumask_var_t cpumask)
{
	struct device *cpu_dev;
	int cpu;

	WARN_ON(cpumask_empty(cpumask));

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

		dev_pm_opp_of_remove_table(cpu_dev);
	}
}
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.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
int dev_pm_opp_of_cpumask_add_table(cpumask_var_t cpumask)
{
	struct device *cpu_dev;
	int cpu, ret = 0;

	WARN_ON(cpumask_empty(cpumask));

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

		ret = dev_pm_opp_of_add_table(cpu_dev);
		if (ret) {
			pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
			       __func__, cpu, ret);

			/* Free all other OPPs */
			dev_pm_opp_of_cpumask_remove_table(cpumask);
			break;
		}
	}

	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.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
{
	struct device_node *np, *tmp_np;
	struct device *tcpu_dev;
	int cpu, ret = 0;

	/* Get OPP descriptor node */
	np = _of_get_opp_desc_node(cpu_dev);
	if (!np) {
		dev_dbg(cpu_dev, "%s: Couldn't find cpu_dev node.\n", __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;

		tcpu_dev = get_cpu_device(cpu);
		if (!tcpu_dev) {
			dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
				__func__, cpu);
			ret = -ENODEV;
			goto put_cpu_node;
		}

		/* Get OPP descriptor node */
		tmp_np = _of_get_opp_desc_node(tcpu_dev);
		if (!tmp_np) {
			dev_err(tcpu_dev, "%s: Couldn't find tcpu_dev node.\n",
				__func__);
			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);
#endif

/**
 * dev_pm_opp_set_sharing_cpus() - Mark OPP table as shared by few CPUs
 * @cpu_dev:	CPU device for which we do this operation
 * @cpumask:	cpumask of the CPUs which share the OPP table with @cpu_dev
 *
 * This marks OPP table of the @cpu_dev as shared by the CPUs present in
 * @cpumask.
 *
 * Returns -ENODEV if OPP table isn't already present.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
				const cpumask_var_t cpumask)
{
	struct opp_device *opp_dev;
	struct opp_table *opp_table;
	struct device *dev;
	int cpu, ret = 0;

	mutex_lock(&opp_table_lock);

	opp_table = _find_opp_table(cpu_dev);
	if (IS_ERR(opp_table)) {
		ret = PTR_ERR(opp_table);
		goto unlock;
	}

	for_each_cpu(cpu, cpumask) {
		if (cpu == cpu_dev->id)
			continue;

		dev = get_cpu_device(cpu);
		if (!dev) {
			dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
				__func__, cpu);
			continue;
		}

		opp_dev = _add_opp_dev(dev, opp_table);
		if (!opp_dev) {
			dev_err(dev, "%s: failed to add opp-dev for cpu%d device\n",
				__func__, cpu);
			continue;
		}

		/* Mark opp-table as multiple CPUs are sharing it now */
		opp_table->shared_opp = true;
	}
unlock:
	mutex_unlock(&opp_table_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);

/**
 * dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
 * @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 -ENODEV if OPP table isn't already present.
 *
 * Locking: The internal opp_table and opp structures are RCU protected.
 * Hence this function internally uses RCU updater strategy with mutex locks
 * to keep the integrity of the internal data structures. Callers should ensure
 * that this function is *NOT* called under RCU protection or in contexts where
 * mutex cannot be locked.
 */
int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
{
	struct opp_device *opp_dev;
	struct opp_table *opp_table;
	int ret = 0;

	mutex_lock(&opp_table_lock);

	opp_table = _find_opp_table(cpu_dev);
	if (IS_ERR(opp_table)) {
		ret = PTR_ERR(opp_table);
		goto unlock;
	}

	cpumask_clear(cpumask);

	if (opp_table->shared_opp) {
		list_for_each_entry(opp_dev, &opp_table->dev_list, node)
			cpumask_set_cpu(opp_dev->dev->id, cpumask);
	} else {
		cpumask_set_cpu(cpu_dev->id, cpumask);
	}

unlock:
	mutex_unlock(&opp_table_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_sharing_cpus);
Commit	Line	Data
a0dd7b79	1	/*
33692dc3	2	* Generic OPP helper interface for CPU device
a0dd7b79 NM	3	*
	4	* Copyright (C) 2009-2014 Texas Instruments Incorporated.
	5	* Nishanth Menon
	6	* Romit Dasgupta
	7	* Kevin Hilman
	8	*
	9	* This program is free software; you can redistribute it and/or modify
	10	* it under the terms of the GNU General Public License version 2 as
	11	* published by the Free Software Foundation.
	12	*/
d6d2a528 VK	13
	14	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	15
f59d3ee8	16	#include <linux/cpu.h>
a0dd7b79	17	#include <linux/cpufreq.h>
a0dd7b79 NM	18	#include <linux/err.h>
	19	#include <linux/errno.h>
	20	#include <linux/export.h>
f59d3ee8	21	#include <linux/of.h>
a0dd7b79 NM	22	#include <linux/slab.h>
a0dd7b79 NM	23
f59d3ee8 VK	24	#include "opp.h"
f59d3ee8 VK	25
33692dc3	26	#ifdef CONFIG_CPU_FREQ
f59d3ee8	27
a0dd7b79 NM	28	/**
	29	* dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
	30	* @dev: device for which we do this operation
	31	* @table: Cpufreq table returned back to caller
	32	*
	33	* Generate a cpufreq table for a provided device- this assumes that the
2c2709dc	34	* opp table is already initialized and ready for usage.
a0dd7b79 NM	35	*
	36	* This function allocates required memory for the cpufreq table. It is
	37	* expected that the caller does the required maintenance such as freeing
	38	* the table as required.
	39	*
	40	* Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
	41	* if no memory available for the operation (table is not populated), returns 0
	42	* if successful and table is populated.
	43	*
	44	* WARNING: It is important for the callers to ensure refreshing their copy of
	45	* the table if any of the mentioned functions have been invoked in the interim.
	46	*
2c2709dc	47	* Locking: The internal opp_table and opp structures are RCU protected.
a0dd7b79 NM	48	* Since we just use the regular accessor functions to access the internal data
	49	* structures, we use RCU read lock inside this function. As a result, users of
	50	* this function DONOT need to use explicit locks for invoking.
	51	*/
	52	int dev_pm_opp_init_cpufreq_table(struct device *dev,
	53	struct cpufreq_frequency_table **table)
	54	{
	55	struct dev_pm_opp *opp;
	56	struct cpufreq_frequency_table *freq_table = NULL;
	57	int i, max_opps, ret = 0;
	58	unsigned long rate;
	59
	60	rcu_read_lock();
	61
	62	max_opps = dev_pm_opp_get_opp_count(dev);
	63	if (max_opps <= 0) {
	64	ret = max_opps ? max_opps : -ENODATA;
	65	goto out;
	66	}
	67
d3599920	68	freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
a0dd7b79 NM	69	if (!freq_table) {
	70	ret = -ENOMEM;
	71	goto out;
	72	}
	73
	74	for (i = 0, rate = 0; i < max_opps; i++, rate++) {
	75	/* find next rate */
	76	opp = dev_pm_opp_find_freq_ceil(dev, &rate);
	77	if (IS_ERR(opp)) {
	78	ret = PTR_ERR(opp);
	79	goto out;
	80	}
	81	freq_table[i].driver_data = i;
	82	freq_table[i].frequency = rate / 1000;
79eea44a BZ	83
	84	/* Is Boost/turbo opp ? */
	85	if (dev_pm_opp_is_turbo(opp))
	86	freq_table[i].flags = CPUFREQ_BOOST_FREQ;
a0dd7b79 NM	87	}
	88
	89	freq_table[i].driver_data = i;
	90	freq_table[i].frequency = CPUFREQ_TABLE_END;
	91
	92	*table = &freq_table[0];
	93
	94	out:
	95	rcu_read_unlock();
	96	if (ret)
	97	kfree(freq_table);
	98
	99	return ret;
	100	}
	101	EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
	102
	103	/**
	104	* dev_pm_opp_free_cpufreq_table() - free the cpufreq table
	105	* @dev: device for which we do this operation
	106	* @table: table to free
	107	*
	108	* Free up the table allocated by dev_pm_opp_init_cpufreq_table
	109	*/
	110	void dev_pm_opp_free_cpufreq_table(struct device *dev,
	111	struct cpufreq_frequency_table **table)
	112	{
	113	if (!table)
	114	return;
	115
	116	kfree(*table);
	117	*table = NULL;
	118	}
	119	EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);
33692dc3	120	#endif /* CONFIG_CPU_FREQ */
f59d3ee8	121
f59d3ee8	122	#ifdef CONFIG_OF
45ca36ad VK	123	/**
	124	* dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
	125	* @cpumask: cpumask for which OPP table needs to be removed
	126	*
	127	* This removes the OPP tables for CPUs present in the @cpumask.
	128	*
	129	* Locking: The internal opp_table and opp structures are RCU protected.
	130	* Hence this function internally uses RCU updater strategy with mutex locks
	131	* to keep the integrity of the internal data structures. Callers should ensure
	132	* that this function is NOT called under RCU protection or in contexts where
	133	* mutex cannot be locked.
	134	*/
f59d3ee8 VK	135	void dev_pm_opp_of_cpumask_remove_table(cpumask_var_t cpumask)
	136	{
	137	struct device *cpu_dev;
	138	int cpu;
	139
	140	WARN_ON(cpumask_empty(cpumask));
	141
	142	for_each_cpu(cpu, cpumask) {
	143	cpu_dev = get_cpu_device(cpu);
	144	if (!cpu_dev) {
	145	pr_err("%s: failed to get cpu%d device\n", __func__,
	146	cpu);
	147	continue;
	148	}
	149
	150	dev_pm_opp_of_remove_table(cpu_dev);
	151	}
	152	}
	153	EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
	154
45ca36ad VK	155	/**
	156	* dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
	157	* @cpumask: cpumask for which OPP table needs to be added.
	158	*
	159	* This adds the OPP tables for CPUs present in the @cpumask.
	160	*
	161	* Locking: The internal opp_table and opp structures are RCU protected.
	162	* Hence this function internally uses RCU updater strategy with mutex locks
	163	* to keep the integrity of the internal data structures. Callers should ensure
	164	* that this function is NOT called under RCU protection or in contexts where
	165	* mutex cannot be locked.
	166	*/
f59d3ee8 VK	167	int dev_pm_opp_of_cpumask_add_table(cpumask_var_t cpumask)
	168	{
	169	struct device *cpu_dev;
	170	int cpu, ret = 0;
	171
	172	WARN_ON(cpumask_empty(cpumask));
	173
	174	for_each_cpu(cpu, cpumask) {
	175	cpu_dev = get_cpu_device(cpu);
	176	if (!cpu_dev) {
	177	pr_err("%s: failed to get cpu%d device\n", __func__,
	178	cpu);
	179	continue;
	180	}
	181
	182	ret = dev_pm_opp_of_add_table(cpu_dev);
	183	if (ret) {
	184	pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
	185	__func__, cpu, ret);
	186
	187	/* Free all other OPPs */
	188	dev_pm_opp_of_cpumask_remove_table(cpumask);
	189	break;
	190	}
	191	}
	192
	193	return ret;
	194	}
	195	EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
	196
	197	/*
	198	* Works only for OPP v2 bindings.
	199	*
f59d3ee8 VK	200	* Returns -ENOENT if operating-points-v2 bindings aren't supported.
f59d3ee8 VK	201	*/
45ca36ad VK	202	/**
	203	* dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
	204	* @cpu_dev using operating-points-v2
	205	* bindings.
	206	*
	207	* @cpu_dev: CPU device for which we do this operation
	208	* @cpumask: cpumask to update with information of sharing CPUs
	209	*
	210	* This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
	211	*
	212	* Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
	213	*
	214	* Locking: The internal opp_table and opp structures are RCU protected.
	215	* Hence this function internally uses RCU updater strategy with mutex locks
	216	* to keep the integrity of the internal data structures. Callers should ensure
	217	* that this function is NOT called under RCU protection or in contexts where
	218	* mutex cannot be locked.
	219	*/
f59d3ee8 VK	220	int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
	221	{
	222	struct device_node np, tmp_np;
	223	struct device *tcpu_dev;
	224	int cpu, ret = 0;
	225
	226	/* Get OPP descriptor node */
	227	np = _of_get_opp_desc_node(cpu_dev);
	228	if (!np) {
a6eed752	229	dev_dbg(cpu_dev, "%s: Couldn't find cpu_dev node.\n", __func__);
f59d3ee8 VK	230	return -ENOENT;
	231	}
	232
d9de19b1 PCC	233	cpumask_set_cpu(cpu_dev->id, cpumask);
d9de19b1 PCC	234
f59d3ee8 VK	235	/* OPPs are shared ? */
	236	if (!of_property_read_bool(np, "opp-shared"))
	237	goto put_cpu_node;
	238
	239	for_each_possible_cpu(cpu) {
	240	if (cpu == cpu_dev->id)
	241	continue;
	242
	243	tcpu_dev = get_cpu_device(cpu);
	244	if (!tcpu_dev) {
	245	dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
	246	__func__, cpu);
	247	ret = -ENODEV;
	248	goto put_cpu_node;
	249	}
	250
	251	/* Get OPP descriptor node */
	252	tmp_np = _of_get_opp_desc_node(tcpu_dev);
	253	if (!tmp_np) {
a6eed752 DC	254	dev_err(tcpu_dev, "%s: Couldn't find tcpu_dev node.\n",
	255	__func__);
	256	ret = -ENOENT;
f59d3ee8 VK	257	goto put_cpu_node;
	258	}
	259
	260	/* CPUs are sharing opp node */
	261	if (np == tmp_np)
	262	cpumask_set_cpu(cpu, cpumask);
	263
	264	of_node_put(tmp_np);
	265	}
	266
	267	put_cpu_node:
	268	of_node_put(np);
	269	return ret;
	270	}
	271	EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
	272	#endif
2c93104f VK	273
	274	/**
	275	* dev_pm_opp_set_sharing_cpus() - Mark OPP table as shared by few CPUs
	276	* @cpu_dev: CPU device for which we do this operation
	277	* @cpumask: cpumask of the CPUs which share the OPP table with @cpu_dev
	278	*
	279	* This marks OPP table of the @cpu_dev as shared by the CPUs present in
	280	* @cpumask.
	281	*
	282	* Returns -ENODEV if OPP table isn't already present.
	283	*
	284	* Locking: The internal opp_table and opp structures are RCU protected.
	285	* Hence this function internally uses RCU updater strategy with mutex locks
	286	* to keep the integrity of the internal data structures. Callers should ensure
	287	* that this function is NOT called under RCU protection or in contexts where
	288	* mutex cannot be locked.
	289	*/
dde370b2 VK	290	int dev_pm_opp_set_sharing_cpus(struct device *cpu_dev,
dde370b2 VK	291	const cpumask_var_t cpumask)
2c93104f VK	292	{
	293	struct opp_device *opp_dev;
	294	struct opp_table *opp_table;
	295	struct device *dev;
	296	int cpu, ret = 0;
	297
	298	mutex_lock(&opp_table_lock);
	299
	300	opp_table = _find_opp_table(cpu_dev);
	301	if (IS_ERR(opp_table)) {
	302	ret = PTR_ERR(opp_table);
	303	goto unlock;
	304	}
	305
	306	for_each_cpu(cpu, cpumask) {
	307	if (cpu == cpu_dev->id)
	308	continue;
	309
	310	dev = get_cpu_device(cpu);
	311	if (!dev) {
	312	dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
	313	__func__, cpu);
	314	continue;
	315	}
	316
	317	opp_dev = _add_opp_dev(dev, opp_table);
	318	if (!opp_dev) {
	319	dev_err(dev, "%s: failed to add opp-dev for cpu%d device\n",
	320	__func__, cpu);
	321	continue;
	322	}
46e7a4e1 VK	323
	324	/* Mark opp-table as multiple CPUs are sharing it now */
	325	opp_table->shared_opp = true;
2c93104f VK	326	}
	327	unlock:
	328	mutex_unlock(&opp_table_lock);
	329
	330	return ret;
	331	}
	332	EXPORT_SYMBOL_GPL(dev_pm_opp_set_sharing_cpus);
6f707daa VK	333
	334	/**
	335	* dev_pm_opp_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with @cpu_dev
	336	* @cpu_dev: CPU device for which we do this operation
	337	* @cpumask: cpumask to update with information of sharing CPUs
	338	*
	339	* This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
	340	*
	341	* Returns -ENODEV if OPP table isn't already present.
	342	*
	343	* Locking: The internal opp_table and opp structures are RCU protected.
	344	* Hence this function internally uses RCU updater strategy with mutex locks
	345	* to keep the integrity of the internal data structures. Callers should ensure
	346	* that this function is NOT called under RCU protection or in contexts where
	347	* mutex cannot be locked.
	348	*/
	349	int dev_pm_opp_get_sharing_cpus(struct device *cpu_dev, cpumask_var_t cpumask)
	350	{
	351	struct opp_device *opp_dev;
	352	struct opp_table *opp_table;
	353	int ret = 0;
	354
	355	mutex_lock(&opp_table_lock);
	356
	357	opp_table = _find_opp_table(cpu_dev);
	358	if (IS_ERR(opp_table)) {
	359	ret = PTR_ERR(opp_table);
	360	goto unlock;
	361	}
	362
	363	cpumask_clear(cpumask);
	364
	365	if (opp_table->shared_opp) {
	366	list_for_each_entry(opp_dev, &opp_table->dev_list, node)
	367	cpumask_set_cpu(opp_dev->dev->id, cpumask);
	368	} else {
	369	cpumask_set_cpu(cpu_dev->id, cpumask);
	370	}
	371
	372	unlock:
	373	mutex_unlock(&opp_table_lock);
	374
	375	return ret;
	376	}
	377	EXPORT_SYMBOL_GPL(dev_pm_opp_get_sharing_cpus);