1b5c1be2c8
Allow devfreq drivers to register a preferred governor name and when the devfreq governor loads itself at a later point required drivers are managed appropriately, at the time of unload of a devfreq governor, stop managing those drivers as well. Since the governor structures do not need to be exposed anymore, remove the definitions and make them static NOTE: devfreq_list_lock is now used to protect governor start and stop - as this allows us to protect governors and devfreq with the proper dependencies as needed. As part of this change, change the registration of exynos bus driver to request for ondemand using the governor name. Cc: Rajagopal Venkat <rajagopal.venkat@linaro.org> Cc: MyungJoo Ham <myungjoo.ham@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Kevin Hilman <khilman@ti.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Nishanth Menon <nm@ti.com> [Merge conflict resolved by MyungJoo Ham] Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
145 lines
3.4 KiB
C
145 lines
3.4 KiB
C
/*
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* linux/drivers/devfreq/governor_simpleondemand.c
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*
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* Copyright (C) 2011 Samsung Electronics
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* MyungJoo Ham <myungjoo.ham@samsung.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/errno.h>
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#include <linux/devfreq.h>
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#include <linux/math64.h>
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#include "governor.h"
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/* Default constants for DevFreq-Simple-Ondemand (DFSO) */
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#define DFSO_UPTHRESHOLD (90)
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#define DFSO_DOWNDIFFERENCTIAL (5)
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static int devfreq_simple_ondemand_func(struct devfreq *df,
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unsigned long *freq)
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{
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struct devfreq_dev_status stat;
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int err = df->profile->get_dev_status(df->dev.parent, &stat);
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unsigned long long a, b;
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unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
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unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
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struct devfreq_simple_ondemand_data *data = df->data;
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unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
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if (err)
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return err;
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if (data) {
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if (data->upthreshold)
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dfso_upthreshold = data->upthreshold;
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if (data->downdifferential)
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dfso_downdifferential = data->downdifferential;
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}
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if (dfso_upthreshold > 100 ||
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dfso_upthreshold < dfso_downdifferential)
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return -EINVAL;
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/* Assume MAX if it is going to be divided by zero */
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if (stat.total_time == 0) {
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*freq = max;
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return 0;
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}
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/* Prevent overflow */
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if (stat.busy_time >= (1 << 24) || stat.total_time >= (1 << 24)) {
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stat.busy_time >>= 7;
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stat.total_time >>= 7;
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}
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/* Set MAX if it's busy enough */
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if (stat.busy_time * 100 >
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stat.total_time * dfso_upthreshold) {
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*freq = max;
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return 0;
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}
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/* Set MAX if we do not know the initial frequency */
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if (stat.current_frequency == 0) {
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*freq = max;
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return 0;
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}
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/* Keep the current frequency */
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if (stat.busy_time * 100 >
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stat.total_time * (dfso_upthreshold - dfso_downdifferential)) {
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*freq = stat.current_frequency;
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return 0;
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}
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/* Set the desired frequency based on the load */
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a = stat.busy_time;
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a *= stat.current_frequency;
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b = div_u64(a, stat.total_time);
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b *= 100;
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b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
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*freq = (unsigned long) b;
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if (df->min_freq && *freq < df->min_freq)
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*freq = df->min_freq;
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if (df->max_freq && *freq > df->max_freq)
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*freq = df->max_freq;
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return 0;
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}
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static int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
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unsigned int event, void *data)
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{
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switch (event) {
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case DEVFREQ_GOV_START:
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devfreq_monitor_start(devfreq);
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break;
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case DEVFREQ_GOV_STOP:
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devfreq_monitor_stop(devfreq);
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break;
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case DEVFREQ_GOV_INTERVAL:
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devfreq_interval_update(devfreq, (unsigned int *)data);
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break;
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case DEVFREQ_GOV_SUSPEND:
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devfreq_monitor_suspend(devfreq);
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break;
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case DEVFREQ_GOV_RESUME:
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devfreq_monitor_resume(devfreq);
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break;
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default:
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break;
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}
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return 0;
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}
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static struct devfreq_governor devfreq_simple_ondemand = {
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.name = "simple_ondemand",
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.get_target_freq = devfreq_simple_ondemand_func,
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.event_handler = devfreq_simple_ondemand_handler,
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};
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static int __init devfreq_simple_ondemand_init(void)
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{
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return devfreq_add_governor(&devfreq_simple_ondemand);
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}
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subsys_initcall(devfreq_simple_ondemand_init);
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static void __exit devfreq_simple_ondemand_exit(void)
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{
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int ret;
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ret = devfreq_remove_governor(&devfreq_simple_ondemand);
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if (ret)
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pr_err("%s: failed remove governor %d\n", __func__, ret);
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return;
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}
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module_exit(devfreq_simple_ondemand_exit);
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