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![Saravana Kannan](/assets/img/avatar_default.png)
Look at the required OPPs of the "parent" device to determine the OPP that is required from the slave device managed by the passive governor. This allows having mappings between a parent device and a slave device even when they don't have the same number of OPPs. While at it do a minor spell-fix and remove out label. Signed-off-by: Saravana Kannan <saravanak@google.com> Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com> Acked-by: Chanwoo Choi <cw00.choi@samsung.com> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org> [ Viresh: Rearranged code and clean error paths ] Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
191 lines
5.2 KiB
C
191 lines
5.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/drivers/devfreq/governor_passive.c
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*
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* Copyright (C) 2016 Samsung Electronics
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* Author: Chanwoo Choi <cw00.choi@samsung.com>
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* Author: MyungJoo Ham <myungjoo.ham@samsung.com>
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*/
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/devfreq.h>
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#include "governor.h"
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static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
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unsigned long *freq)
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{
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struct devfreq_passive_data *p_data
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= (struct devfreq_passive_data *)devfreq->data;
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struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
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unsigned long child_freq = ULONG_MAX;
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struct dev_pm_opp *opp, *p_opp;
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int i, count;
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/*
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* If the devfreq device with passive governor has the specific method
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* to determine the next frequency, should use the get_target_freq()
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* of struct devfreq_passive_data.
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*/
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if (p_data->get_target_freq)
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return p_data->get_target_freq(devfreq, freq);
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/*
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* If the parent and passive devfreq device uses the OPP table,
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* get the next frequency by using the OPP table.
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*/
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/*
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* - parent devfreq device uses the governors except for passive.
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* - passive devfreq device uses the passive governor.
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*
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* Each devfreq has the OPP table. After deciding the new frequency
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* from the governor of parent devfreq device, the passive governor
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* need to get the index of new frequency on OPP table of parent
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* device. And then the index is used for getting the suitable
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* new frequency for passive devfreq device.
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*/
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if (!devfreq->profile || !devfreq->profile->freq_table
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|| devfreq->profile->max_state <= 0)
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return -EINVAL;
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/*
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* The passive governor have to get the correct frequency from OPP
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* list of parent device. Because in this case, *freq is temporary
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* value which is decided by ondemand governor.
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*/
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if (devfreq->opp_table && parent_devfreq->opp_table) {
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p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent,
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freq, 0);
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if (IS_ERR(p_opp))
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return PTR_ERR(p_opp);
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opp = dev_pm_opp_xlate_required_opp(parent_devfreq->opp_table,
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devfreq->opp_table, p_opp);
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dev_pm_opp_put(p_opp);
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if (IS_ERR(opp))
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return PTR_ERR(opp);
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*freq = dev_pm_opp_get_freq(opp);
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dev_pm_opp_put(opp);
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return 0;
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}
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/*
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* Get the OPP table's index of decided frequency by governor
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* of parent device.
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*/
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for (i = 0; i < parent_devfreq->profile->max_state; i++)
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if (parent_devfreq->profile->freq_table[i] == *freq)
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break;
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if (i == parent_devfreq->profile->max_state)
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return -EINVAL;
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/* Get the suitable frequency by using index of parent device. */
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if (i < devfreq->profile->max_state) {
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child_freq = devfreq->profile->freq_table[i];
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} else {
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count = devfreq->profile->max_state;
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child_freq = devfreq->profile->freq_table[count - 1];
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}
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/* Return the suitable frequency for passive device. */
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*freq = child_freq;
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return 0;
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}
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static int devfreq_passive_notifier_call(struct notifier_block *nb,
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unsigned long event, void *ptr)
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{
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struct devfreq_passive_data *data
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= container_of(nb, struct devfreq_passive_data, nb);
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struct devfreq *devfreq = (struct devfreq *)data->this;
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struct devfreq *parent = (struct devfreq *)data->parent;
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struct devfreq_freqs *freqs = (struct devfreq_freqs *)ptr;
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unsigned long freq = freqs->new;
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int ret = 0;
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mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
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switch (event) {
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case DEVFREQ_PRECHANGE:
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if (parent->previous_freq > freq)
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ret = devfreq_update_target(devfreq, freq);
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break;
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case DEVFREQ_POSTCHANGE:
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if (parent->previous_freq < freq)
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ret = devfreq_update_target(devfreq, freq);
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break;
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}
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mutex_unlock(&devfreq->lock);
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if (ret < 0)
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dev_warn(&devfreq->dev,
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"failed to update devfreq using passive governor\n");
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return NOTIFY_DONE;
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}
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static int devfreq_passive_event_handler(struct devfreq *devfreq,
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unsigned int event, void *data)
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{
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struct devfreq_passive_data *p_data
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= (struct devfreq_passive_data *)devfreq->data;
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struct devfreq *parent = (struct devfreq *)p_data->parent;
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struct notifier_block *nb = &p_data->nb;
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int ret = 0;
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if (!parent)
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return -EPROBE_DEFER;
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switch (event) {
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case DEVFREQ_GOV_START:
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if (!p_data->this)
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p_data->this = devfreq;
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nb->notifier_call = devfreq_passive_notifier_call;
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ret = devfreq_register_notifier(parent, nb,
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DEVFREQ_TRANSITION_NOTIFIER);
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break;
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case DEVFREQ_GOV_STOP:
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WARN_ON(devfreq_unregister_notifier(parent, nb,
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DEVFREQ_TRANSITION_NOTIFIER));
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break;
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default:
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break;
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}
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return ret;
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}
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static struct devfreq_governor devfreq_passive = {
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.name = DEVFREQ_GOV_PASSIVE,
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.flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
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.get_target_freq = devfreq_passive_get_target_freq,
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.event_handler = devfreq_passive_event_handler,
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};
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static int __init devfreq_passive_init(void)
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{
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return devfreq_add_governor(&devfreq_passive);
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}
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subsys_initcall(devfreq_passive_init);
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static void __exit devfreq_passive_exit(void)
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{
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int ret;
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ret = devfreq_remove_governor(&devfreq_passive);
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if (ret)
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pr_err("%s: failed remove governor %d\n", __func__, ret);
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}
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module_exit(devfreq_passive_exit);
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MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
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MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
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MODULE_DESCRIPTION("DEVFREQ Passive governor");
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MODULE_LICENSE("GPL v2");
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