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Commit cca4b8e8 authored by Rama Aparna Mallavarapu's avatar Rama Aparna Mallavarapu
Browse files

devfreq: memlat: Add suspend/resume for mem_latency 



Add suspend/resume support for the mem_latency governor. Uses hwmon driver-
defined suspend/resume calls in addition to monitor start/stop calls within
the devfreq framework.

Change-Id: I900b322a05cd0312f082d70640e21851879cb18c
Signed-off-by: default avatarJonathan Avila <avilaj@codeaurora.org>
Signed-off-by: default avatarRama Aparna Mallavarapu <aparnam@codeaurora.org>
parent 0114bf7e

drivers/devfreq/governor_memlat.c

+71 −1
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright (c) 2015-2017, 2019, The Linux Foundation. All rights reserved.

 * Copyright (c) 2015-2018, 2019, The Linux Foundation. All rights reserved.

 */



#define pr_fmt(fmt) "mem_lat: " fmt
@@ -35,6 +35,7 @@ struct memlat_node { 
	struct memlat_hwmon *hw;

	struct devfreq_governor *gov;

	struct attribute_group *attr_grp;

	unsigned long resume_freq;

};



static LIST_HEAD(memlat_list);
@@ -204,6 +205,39 @@ static int gov_start(struct devfreq *df) 
	return ret;

}



static int gov_suspend(struct devfreq *df)

{

	struct memlat_node *node = df->data;

	unsigned long prev_freq = df->previous_freq;



	node->mon_started = false;

	devfreq_monitor_suspend(df);



	mutex_lock(&df->lock);

	update_devfreq(df);

	mutex_unlock(&df->lock);



	node->resume_freq = max(prev_freq, 1UL);



	return 0;

}



static int gov_resume(struct devfreq *df)

{

	struct memlat_node *node = df->data;



	mutex_lock(&df->lock);

	update_devfreq(df);

	mutex_unlock(&df->lock);



	node->resume_freq = 0;



	devfreq_monitor_resume(df);

	node->mon_started = true;



	return 0;

}



static void gov_stop(struct devfreq *df)

{

	struct memlat_node *node = df->data;
@@ -225,6 +259,18 @@ static int devfreq_memlat_get_freq(struct devfreq *df, 
	unsigned long max_freq = 0;

	unsigned int ratio;



	/*

	 * node->resume_freq is set to 0 at the end of resume (after the update)

	 * and is set to df->prev_freq at the end of suspend (after the update).

	 * This function will be called as part of the update_devfreq call in

	 * both scenarios. As a result, this block will cause a 0 vote during

	 * suspend and a vote for df->prev_freq during resume.

	 */

	if (!node->mon_started) {

		*freq = node->resume_freq;

		return 0;

	}



	hw->get_cnt(hw);



	for (i = 0; i < hw->num_cores; i++) {
@@ -323,6 +369,30 @@ static int devfreq_memlat_ev_handler(struct devfreq *df, 
			"Disabled Memory Latency governor\n");

		break;



	case DEVFREQ_GOV_SUSPEND:

		ret = gov_suspend(df);

		if (ret) {

			dev_err(df->dev.parent,

				"Unable to suspend memlat governor (%d)\n",

				ret);

			return ret;

		}



		dev_dbg(df->dev.parent, "Suspended memlat governor\n");

		break;



	case DEVFREQ_GOV_RESUME:

		ret = gov_resume(df);

		if (ret) {

			dev_err(df->dev.parent,

				"Unable to resume memlat governor (%d)\n",

				ret);

			return ret;

		}



		dev_dbg(df->dev.parent, "Resumed memlat governor\n");

		break;



	case DEVFREQ_GOV_INTERVAL:

		sample_ms = *(unsigned int *)data;

		sample_ms = max(MIN_MS, sample_ms);