[linux-2.6-block.git] / drivers / devfreq / governor_passive.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * linux/drivers/devfreq/governor_passive.c
 *
 * Copyright (C) 2016 Samsung Electronics
 * Author: Chanwoo Choi <cw00.choi@samsung.com>
 * Author: MyungJoo Ham <myungjoo.ham@samsung.com>
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/devfreq.h>
#include "governor.h"

static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
					unsigned long *freq)
{
	struct devfreq_passive_data *p_data
			= (struct devfreq_passive_data *)devfreq->data;
	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
	unsigned long child_freq = ULONG_MAX;
	struct dev_pm_opp *opp;
	int i, count, ret = 0;

	/*
	 * If the devfreq device with passive governor has the specific method
	 * to determine the next frequency, should use the get_target_freq()
	 * of struct devfreq_passive_data.
	 */
	if (p_data->get_target_freq) {
		ret = p_data->get_target_freq(devfreq, freq);
		goto out;
	}

	/*
	 * If the parent and passive devfreq device uses the OPP table,
	 * get the next frequency by using the OPP table.
	 */

	/*
	 * - parent devfreq device uses the governors except for passive.
	 * - passive devfreq device uses the passive governor.
	 *
	 * Each devfreq has the OPP table. After deciding the new frequency
	 * from the governor of parent devfreq device, the passive governor
	 * need to get the index of new frequency on OPP table of parent
	 * device. And then the index is used for getting the suitable
	 * new frequency for passive devfreq device.
	 */
	if (!devfreq->profile || !devfreq->profile->freq_table
		|| devfreq->profile->max_state <= 0)
		return -EINVAL;

	/*
	 * The passive governor have to get the correct frequency from OPP
	 * list of parent device. Because in this case, *freq is temporary
	 * value which is decided by ondemand governor.
	 */
	opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
	if (IS_ERR(opp)) {
		ret = PTR_ERR(opp);
		goto out;
	}

	dev_pm_opp_put(opp);

	/*
	 * Get the OPP table's index of decided freqeuncy by governor
	 * of parent device.
	 */
	for (i = 0; i < parent_devfreq->profile->max_state; i++)
		if (parent_devfreq->profile->freq_table[i] == *freq)
			break;

	if (i == parent_devfreq->profile->max_state) {
		ret = -EINVAL;
		goto out;
	}

	/* Get the suitable frequency by using index of parent device. */
	if (i < devfreq->profile->max_state) {
		child_freq = devfreq->profile->freq_table[i];
	} else {
		count = devfreq->profile->max_state;
		child_freq = devfreq->profile->freq_table[count - 1];
	}

	/* Return the suitable frequency for passive device. */
	*freq = child_freq;

out:
	return ret;
}

static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
{
	int ret;

	if (!devfreq->governor)
		return -EINVAL;

	mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);

	ret = devfreq->governor->get_target_freq(devfreq, &freq);
	if (ret < 0)
		goto out;

	ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0);
	if (ret < 0)
		goto out;

	if (devfreq->profile->freq_table
		&& (devfreq_update_status(devfreq, freq)))
		dev_err(&devfreq->dev,
			"Couldn't update frequency transition information.\n");

	devfreq->previous_freq = freq;

out:
	mutex_unlock(&devfreq->lock);

	return 0;
}

static int devfreq_passive_notifier_call(struct notifier_block *nb,
				unsigned long event, void *ptr)
{
	struct devfreq_passive_data *data
			= container_of(nb, struct devfreq_passive_data, nb);
	struct devfreq *devfreq = (struct devfreq *)data->this;
	struct devfreq *parent = (struct devfreq *)data->parent;
	struct devfreq_freqs *freqs = (struct devfreq_freqs *)ptr;
	unsigned long freq = freqs->new;

	switch (event) {
	case DEVFREQ_PRECHANGE:
		if (parent->previous_freq > freq)
			update_devfreq_passive(devfreq, freq);
		break;
	case DEVFREQ_POSTCHANGE:
		if (parent->previous_freq < freq)
			update_devfreq_passive(devfreq, freq);
		break;
	}

	return NOTIFY_DONE;
}

static int devfreq_passive_event_handler(struct devfreq *devfreq,
				unsigned int event, void *data)
{
	struct device *dev = devfreq->dev.parent;
	struct devfreq_passive_data *p_data
			= (struct devfreq_passive_data *)devfreq->data;
	struct devfreq *parent = (struct devfreq *)p_data->parent;
	struct notifier_block *nb = &p_data->nb;
	int ret = 0;

	if (!parent)
		return -EPROBE_DEFER;

	switch (event) {
	case DEVFREQ_GOV_START:
		if (!p_data->this)
			p_data->this = devfreq;

		nb->notifier_call = devfreq_passive_notifier_call;
		ret = devm_devfreq_register_notifier(dev, parent, nb,
					DEVFREQ_TRANSITION_NOTIFIER);
		break;
	case DEVFREQ_GOV_STOP:
		devm_devfreq_unregister_notifier(dev, parent, nb,
					DEVFREQ_TRANSITION_NOTIFIER);
		break;
	default:
		break;
	}

	return ret;
}

static struct devfreq_governor devfreq_passive = {
	.name = DEVFREQ_GOV_PASSIVE,
	.immutable = 1,
	.get_target_freq = devfreq_passive_get_target_freq,
	.event_handler = devfreq_passive_event_handler,
};

static int __init devfreq_passive_init(void)
{
	return devfreq_add_governor(&devfreq_passive);
}
subsys_initcall(devfreq_passive_init);

static void __exit devfreq_passive_exit(void)
{
	int ret;

	ret = devfreq_remove_governor(&devfreq_passive);
	if (ret)
		pr_err("%s: failed remove governor %d\n", __func__, ret);
}
module_exit(devfreq_passive_exit);

MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
MODULE_DESCRIPTION("DEVFREQ Passive governor");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
99613311 CC	2	/*
	3	* linux/drivers/devfreq/governor_passive.c
	4	*
	5	* Copyright (C) 2016 Samsung Electronics
	6	* Author: Chanwoo Choi <cw00.choi@samsung.com>
	7	* Author: MyungJoo Ham <myungjoo.ham@samsung.com>
99613311 CC	8	*/
	9
	10	#include <linux/module.h>
	11	#include <linux/device.h>
	12	#include <linux/devfreq.h>
	13	#include "governor.h"
	14
	15	static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
	16	unsigned long *freq)
	17	{
	18	struct devfreq_passive_data *p_data
	19	= (struct devfreq_passive_data *)devfreq->data;
	20	struct devfreq parent_devfreq = (struct devfreq )p_data->parent;
	21	unsigned long child_freq = ULONG_MAX;
	22	struct dev_pm_opp *opp;
	23	int i, count, ret = 0;
	24
	25	/*
	26	* If the devfreq device with passive governor has the specific method
	27	* to determine the next frequency, should use the get_target_freq()
	28	* of struct devfreq_passive_data.
	29	*/
	30	if (p_data->get_target_freq) {
	31	ret = p_data->get_target_freq(devfreq, freq);
	32	goto out;
	33	}
	34
	35	/*
	36	* If the parent and passive devfreq device uses the OPP table,
	37	* get the next frequency by using the OPP table.
	38	*/
	39
	40	/*
	41	* - parent devfreq device uses the governors except for passive.
	42	* - passive devfreq device uses the passive governor.
	43	*
	44	* Each devfreq has the OPP table. After deciding the new frequency
	45	* from the governor of parent devfreq device, the passive governor
	46	* need to get the index of new frequency on OPP table of parent
	47	* device. And then the index is used for getting the suitable
	48	* new frequency for passive devfreq device.
	49	*/
	50	if (!devfreq->profile \|\| !devfreq->profile->freq_table
	51	\|\| devfreq->profile->max_state <= 0)
	52	return -EINVAL;
	53
	54	/*
	55	* The passive governor have to get the correct frequency from OPP
	56	* list of parent device. Because in this case, *freq is temporary
	57	* value which is decided by ondemand governor.
	58	*/
99613311	59	opp = devfreq_recommended_opp(parent_devfreq->dev.parent, freq, 0);
99613311 CC	60	if (IS_ERR(opp)) {
	61	ret = PTR_ERR(opp);
	62	goto out;
	63	}
	64
8a31d9d9 VK	65	dev_pm_opp_put(opp);
8a31d9d9 VK	66
99613311 CC	67	/*
	68	* Get the OPP table's index of decided freqeuncy by governor
	69	* of parent device.
	70	*/
	71	for (i = 0; i < parent_devfreq->profile->max_state; i++)
	72	if (parent_devfreq->profile->freq_table[i] == *freq)
	73	break;
	74
	75	if (i == parent_devfreq->profile->max_state) {
	76	ret = -EINVAL;
	77	goto out;
	78	}
	79
	80	/* Get the suitable frequency by using index of parent device. */
	81	if (i < devfreq->profile->max_state) {
	82	child_freq = devfreq->profile->freq_table[i];
	83	} else {
	84	count = devfreq->profile->max_state;
	85	child_freq = devfreq->profile->freq_table[count - 1];
	86	}
	87
	88	/* Return the suitable frequency for passive device. */
	89	*freq = child_freq;
	90
	91	out:
	92	return ret;
	93	}
	94
	95	static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
	96	{
	97	int ret;
	98
	99	if (!devfreq->governor)
	100	return -EINVAL;
	101
	102	mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
	103
	104	ret = devfreq->governor->get_target_freq(devfreq, &freq);
	105	if (ret < 0)
	106	goto out;
	107
	108	ret = devfreq->profile->target(devfreq->dev.parent, &freq, 0);
	109	if (ret < 0)
	110	goto out;
	111
30582c25 CC	112	if (devfreq->profile->freq_table
	113	&& (devfreq_update_status(devfreq, freq)))
	114	dev_err(&devfreq->dev,
	115	"Couldn't update frequency transition information.\n");
	116
99613311 CC	117	devfreq->previous_freq = freq;
	118
	119	out:
	120	mutex_unlock(&devfreq->lock);
	121
	122	return 0;
	123	}
	124
	125	static int devfreq_passive_notifier_call(struct notifier_block *nb,
	126	unsigned long event, void *ptr)
	127	{
	128	struct devfreq_passive_data *data
	129	= container_of(nb, struct devfreq_passive_data, nb);
	130	struct devfreq devfreq = (struct devfreq )data->this;
	131	struct devfreq parent = (struct devfreq )data->parent;
	132	struct devfreq_freqs freqs = (struct devfreq_freqs )ptr;
	133	unsigned long freq = freqs->new;
	134
	135	switch (event) {
	136	case DEVFREQ_PRECHANGE:
	137	if (parent->previous_freq > freq)
	138	update_devfreq_passive(devfreq, freq);
	139	break;
	140	case DEVFREQ_POSTCHANGE:
	141	if (parent->previous_freq < freq)
	142	update_devfreq_passive(devfreq, freq);
	143	break;
	144	}
	145
	146	return NOTIFY_DONE;
	147	}
	148
	149	static int devfreq_passive_event_handler(struct devfreq *devfreq,
	150	unsigned int event, void *data)
	151	{
	152	struct device *dev = devfreq->dev.parent;
	153	struct devfreq_passive_data *p_data
	154	= (struct devfreq_passive_data *)devfreq->data;
	155	struct devfreq parent = (struct devfreq )p_data->parent;
	156	struct notifier_block *nb = &p_data->nb;
	157	int ret = 0;
	158
	159	if (!parent)
	160	return -EPROBE_DEFER;
	161
	162	switch (event) {
	163	case DEVFREQ_GOV_START:
	164	if (!p_data->this)
	165	p_data->this = devfreq;
	166
	167	nb->notifier_call = devfreq_passive_notifier_call;
	168	ret = devm_devfreq_register_notifier(dev, parent, nb,
	169	DEVFREQ_TRANSITION_NOTIFIER);
	170	break;
	171	case DEVFREQ_GOV_STOP:
	172	devm_devfreq_unregister_notifier(dev, parent, nb,
	173	DEVFREQ_TRANSITION_NOTIFIER);
	174	break;
	175	default:
	176	break;
	177	}
	178
	179	return ret;
	180	}
181
182	static struct devfreq_governor devfreq_passive = {
aa7c352f	183	.name = DEVFREQ_GOV_PASSIVE,
bcf23c79	184	.immutable = 1,
99613311 CC	185	.get_target_freq = devfreq_passive_get_target_freq,
	186	.event_handler = devfreq_passive_event_handler,
	187	};
	188
	189	static int __init devfreq_passive_init(void)
	190	{
	191	return devfreq_add_governor(&devfreq_passive);
	192	}
	193	subsys_initcall(devfreq_passive_init);
	194
	195	static void __exit devfreq_passive_exit(void)
	196	{
	197	int ret;
	198
	199	ret = devfreq_remove_governor(&devfreq_passive);
	200	if (ret)
	201	pr_err("%s: failed remove governor %d\n", __func__, ret);
99613311 CC	202	}
	203	module_exit(devfreq_passive_exit);
	204
	205	MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
	206	MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
	207	MODULE_DESCRIPTION("DEVFREQ Passive governor");
	208	MODULE_LICENSE("GPL v2");