[linux-2.6-block.git] / drivers / cpufreq / cpufreq_opp.c

/*
 * Generic OPP helper interface for CPUFreq drivers
 *
 * 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.
 */
#include <linux/cpufreq.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/pm_opp.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>

/**
 * 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 list 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 device_opp 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;
	}

	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);
Commit	Line	Data
a0dd7b79 NM	1	/*
	2	* Generic OPP helper interface for CPUFreq drivers
	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	*/
	13	#include <linux/cpufreq.h>
	14	#include <linux/device.h>
	15	#include <linux/err.h>
	16	#include <linux/errno.h>
	17	#include <linux/export.h>
	18	#include <linux/kernel.h>
	19	#include <linux/pm_opp.h>
	20	#include <linux/rcupdate.h>
	21	#include <linux/slab.h>
	22
	23	/**
	24	* dev_pm_opp_init_cpufreq_table() - create a cpufreq table for a device
	25	* @dev: device for which we do this operation
	26	* @table: Cpufreq table returned back to caller
	27	*
	28	* Generate a cpufreq table for a provided device- this assumes that the
	29	* opp list is already initialized and ready for usage.
	30	*
	31	* This function allocates required memory for the cpufreq table. It is
	32	* expected that the caller does the required maintenance such as freeing
	33	* the table as required.
	34	*
	35	* Returns -EINVAL for bad pointers, -ENODEV if the device is not found, -ENOMEM
	36	* if no memory available for the operation (table is not populated), returns 0
	37	* if successful and table is populated.
	38	*
	39	* WARNING: It is important for the callers to ensure refreshing their copy of
	40	* the table if any of the mentioned functions have been invoked in the interim.
	41	*
	42	* Locking: The internal device_opp and opp structures are RCU protected.
	43	* Since we just use the regular accessor functions to access the internal data
	44	* structures, we use RCU read lock inside this function. As a result, users of
	45	* this function DONOT need to use explicit locks for invoking.
	46	*/
	47	int dev_pm_opp_init_cpufreq_table(struct device *dev,
	48	struct cpufreq_frequency_table **table)
	49	{
	50	struct dev_pm_opp *opp;
	51	struct cpufreq_frequency_table *freq_table = NULL;
	52	int i, max_opps, ret = 0;
	53	unsigned long rate;
	54
	55	rcu_read_lock();
	56
	57	max_opps = dev_pm_opp_get_opp_count(dev);
	58	if (max_opps <= 0) {
	59	ret = max_opps ? max_opps : -ENODATA;
	60	goto out;
	61	}
	62
d3599920	63	freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
a0dd7b79 NM	64	if (!freq_table) {
	65	ret = -ENOMEM;
	66	goto out;
	67	}
	68
	69	for (i = 0, rate = 0; i < max_opps; i++, rate++) {
	70	/* find next rate */
	71	opp = dev_pm_opp_find_freq_ceil(dev, &rate);
	72	if (IS_ERR(opp)) {
	73	ret = PTR_ERR(opp);
	74	goto out;
	75	}
	76	freq_table[i].driver_data = i;
	77	freq_table[i].frequency = rate / 1000;
	78	}
	79
	80	freq_table[i].driver_data = i;
	81	freq_table[i].frequency = CPUFREQ_TABLE_END;
	82
	83	*table = &freq_table[0];
	84
	85	out:
	86	rcu_read_unlock();
	87	if (ret)
	88	kfree(freq_table);
	89
	90	return ret;
	91	}
	92	EXPORT_SYMBOL_GPL(dev_pm_opp_init_cpufreq_table);
	93
	94	/**
	95	* dev_pm_opp_free_cpufreq_table() - free the cpufreq table
	96	* @dev: device for which we do this operation
	97	* @table: table to free
	98	*
	99	* Free up the table allocated by dev_pm_opp_init_cpufreq_table
	100	*/
	101	void dev_pm_opp_free_cpufreq_table(struct device *dev,
	102	struct cpufreq_frequency_table **table)
	103	{
	104	if (!table)
	105	return;
	106
	107	kfree(*table);
	108	*table = NULL;
	109	}
	110	EXPORT_SYMBOL_GPL(dev_pm_opp_free_cpufreq_table);