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path: root/drivers/devfreq/governor_passive.c
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Diffstat (limited to 'drivers/devfreq/governor_passive.c')
-rw-r--r--drivers/devfreq/governor_passive.c451
1 files changed, 451 insertions, 0 deletions
diff --git a/drivers/devfreq/governor_passive.c b/drivers/devfreq/governor_passive.c
new file mode 100644
index 000000000..953cf9a1e
--- /dev/null
+++ b/drivers/devfreq/governor_passive.c
@@ -0,0 +1,451 @@
+// 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/cpu.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/devfreq.h>
+#include <linux/units.h>
+#include "governor.h"
+
+static struct devfreq_cpu_data *
+get_parent_cpu_data(struct devfreq_passive_data *p_data,
+ struct cpufreq_policy *policy)
+{
+ struct devfreq_cpu_data *parent_cpu_data;
+
+ if (!p_data || !policy)
+ return NULL;
+
+ list_for_each_entry(parent_cpu_data, &p_data->cpu_data_list, node)
+ if (parent_cpu_data->first_cpu == cpumask_first(policy->related_cpus))
+ return parent_cpu_data;
+
+ return NULL;
+}
+
+static void delete_parent_cpu_data(struct devfreq_passive_data *p_data)
+{
+ struct devfreq_cpu_data *parent_cpu_data, *tmp;
+
+ list_for_each_entry_safe(parent_cpu_data, tmp, &p_data->cpu_data_list, node) {
+ list_del(&parent_cpu_data->node);
+
+ if (parent_cpu_data->opp_table)
+ dev_pm_opp_put_opp_table(parent_cpu_data->opp_table);
+
+ kfree(parent_cpu_data);
+ }
+}
+
+static unsigned long get_target_freq_by_required_opp(struct device *p_dev,
+ struct opp_table *p_opp_table,
+ struct opp_table *opp_table,
+ unsigned long *freq)
+{
+ struct dev_pm_opp *opp = NULL, *p_opp = NULL;
+ unsigned long target_freq;
+
+ if (!p_dev || !p_opp_table || !opp_table || !freq)
+ return 0;
+
+ p_opp = devfreq_recommended_opp(p_dev, freq, 0);
+ if (IS_ERR(p_opp))
+ return 0;
+
+ opp = dev_pm_opp_xlate_required_opp(p_opp_table, opp_table, p_opp);
+ dev_pm_opp_put(p_opp);
+
+ if (IS_ERR(opp))
+ return 0;
+
+ target_freq = dev_pm_opp_get_freq(opp);
+ dev_pm_opp_put(opp);
+
+ return target_freq;
+}
+
+static int get_target_freq_with_cpufreq(struct devfreq *devfreq,
+ unsigned long *target_freq)
+{
+ struct devfreq_passive_data *p_data =
+ (struct devfreq_passive_data *)devfreq->data;
+ struct devfreq_cpu_data *parent_cpu_data;
+ struct cpufreq_policy *policy;
+ unsigned long cpu, cpu_cur, cpu_min, cpu_max, cpu_percent;
+ unsigned long dev_min, dev_max;
+ unsigned long freq = 0;
+ int ret = 0;
+
+ for_each_online_cpu(cpu) {
+ policy = cpufreq_cpu_get(cpu);
+ if (!policy) {
+ ret = -EINVAL;
+ continue;
+ }
+
+ parent_cpu_data = get_parent_cpu_data(p_data, policy);
+ if (!parent_cpu_data) {
+ cpufreq_cpu_put(policy);
+ continue;
+ }
+
+ /* Get target freq via required opps */
+ cpu_cur = parent_cpu_data->cur_freq * HZ_PER_KHZ;
+ freq = get_target_freq_by_required_opp(parent_cpu_data->dev,
+ parent_cpu_data->opp_table,
+ devfreq->opp_table, &cpu_cur);
+ if (freq) {
+ *target_freq = max(freq, *target_freq);
+ cpufreq_cpu_put(policy);
+ continue;
+ }
+
+ /* Use interpolation if required opps is not available */
+ devfreq_get_freq_range(devfreq, &dev_min, &dev_max);
+
+ cpu_min = parent_cpu_data->min_freq;
+ cpu_max = parent_cpu_data->max_freq;
+ cpu_cur = parent_cpu_data->cur_freq;
+
+ cpu_percent = ((cpu_cur - cpu_min) * 100) / (cpu_max - cpu_min);
+ freq = dev_min + mult_frac(dev_max - dev_min, cpu_percent, 100);
+
+ *target_freq = max(freq, *target_freq);
+ cpufreq_cpu_put(policy);
+ }
+
+ return ret;
+}
+
+static int get_target_freq_with_devfreq(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;
+ int i, count;
+
+ /* Get target freq via required opps */
+ child_freq = get_target_freq_by_required_opp(parent_devfreq->dev.parent,
+ parent_devfreq->opp_table,
+ devfreq->opp_table, freq);
+ if (child_freq)
+ goto out;
+
+ /* Use interpolation if required opps is not available */
+ for (i = 0; i < parent_devfreq->max_state; i++)
+ if (parent_devfreq->freq_table[i] == *freq)
+ break;
+
+ if (i == parent_devfreq->max_state)
+ return -EINVAL;
+
+ if (i < devfreq->max_state) {
+ child_freq = devfreq->freq_table[i];
+ } else {
+ count = devfreq->max_state;
+ child_freq = devfreq->freq_table[count - 1];
+ }
+
+out:
+ *freq = child_freq;
+
+ return 0;
+}
+
+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;
+ int ret;
+
+ if (!p_data)
+ return -EINVAL;
+
+ /*
+ * 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)
+ return p_data->get_target_freq(devfreq, freq);
+
+ switch (p_data->parent_type) {
+ case DEVFREQ_PARENT_DEV:
+ ret = get_target_freq_with_devfreq(devfreq, freq);
+ break;
+ case CPUFREQ_PARENT_DEV:
+ ret = get_target_freq_with_cpufreq(devfreq, freq);
+ break;
+ default:
+ ret = -EINVAL;
+ dev_err(&devfreq->dev, "Invalid parent type\n");
+ break;
+ }
+
+ return ret;
+}
+
+static int cpufreq_passive_notifier_call(struct notifier_block *nb,
+ unsigned long event, void *ptr)
+{
+ struct devfreq_passive_data *p_data =
+ container_of(nb, struct devfreq_passive_data, nb);
+ struct devfreq *devfreq = (struct devfreq *)p_data->this;
+ struct devfreq_cpu_data *parent_cpu_data;
+ struct cpufreq_freqs *freqs = ptr;
+ unsigned int cur_freq;
+ int ret;
+
+ if (event != CPUFREQ_POSTCHANGE || !freqs)
+ return 0;
+
+ parent_cpu_data = get_parent_cpu_data(p_data, freqs->policy);
+ if (!parent_cpu_data || parent_cpu_data->cur_freq == freqs->new)
+ return 0;
+
+ cur_freq = parent_cpu_data->cur_freq;
+ parent_cpu_data->cur_freq = freqs->new;
+
+ mutex_lock(&devfreq->lock);
+ ret = devfreq_update_target(devfreq, freqs->new);
+ mutex_unlock(&devfreq->lock);
+ if (ret) {
+ parent_cpu_data->cur_freq = cur_freq;
+ dev_err(&devfreq->dev, "failed to update the frequency.\n");
+ return ret;
+ }
+
+ return 0;
+}
+
+static int cpufreq_passive_unregister_notifier(struct devfreq *devfreq)
+{
+ struct devfreq_passive_data *p_data
+ = (struct devfreq_passive_data *)devfreq->data;
+ int ret;
+
+ if (p_data->nb.notifier_call) {
+ ret = cpufreq_unregister_notifier(&p_data->nb,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ if (ret < 0)
+ return ret;
+ }
+
+ delete_parent_cpu_data(p_data);
+
+ return 0;
+}
+
+static int cpufreq_passive_register_notifier(struct devfreq *devfreq)
+{
+ struct devfreq_passive_data *p_data
+ = (struct devfreq_passive_data *)devfreq->data;
+ struct device *dev = devfreq->dev.parent;
+ struct opp_table *opp_table = NULL;
+ struct devfreq_cpu_data *parent_cpu_data;
+ struct cpufreq_policy *policy;
+ struct device *cpu_dev;
+ unsigned int cpu;
+ int ret;
+
+ p_data->cpu_data_list
+ = (struct list_head)LIST_HEAD_INIT(p_data->cpu_data_list);
+
+ p_data->nb.notifier_call = cpufreq_passive_notifier_call;
+ ret = cpufreq_register_notifier(&p_data->nb, CPUFREQ_TRANSITION_NOTIFIER);
+ if (ret) {
+ dev_err(dev, "failed to register cpufreq notifier\n");
+ p_data->nb.notifier_call = NULL;
+ goto err;
+ }
+
+ for_each_possible_cpu(cpu) {
+ policy = cpufreq_cpu_get(cpu);
+ if (!policy) {
+ ret = -EPROBE_DEFER;
+ goto err;
+ }
+
+ parent_cpu_data = get_parent_cpu_data(p_data, policy);
+ if (parent_cpu_data) {
+ cpufreq_cpu_put(policy);
+ continue;
+ }
+
+ parent_cpu_data = kzalloc(sizeof(*parent_cpu_data),
+ GFP_KERNEL);
+ if (!parent_cpu_data) {
+ ret = -ENOMEM;
+ goto err_put_policy;
+ }
+
+ cpu_dev = get_cpu_device(cpu);
+ if (!cpu_dev) {
+ dev_err(dev, "failed to get cpu device\n");
+ ret = -ENODEV;
+ goto err_free_cpu_data;
+ }
+
+ opp_table = dev_pm_opp_get_opp_table(cpu_dev);
+ if (IS_ERR(opp_table)) {
+ dev_err(dev, "failed to get opp_table of cpu%d\n", cpu);
+ ret = PTR_ERR(opp_table);
+ goto err_free_cpu_data;
+ }
+
+ parent_cpu_data->dev = cpu_dev;
+ parent_cpu_data->opp_table = opp_table;
+ parent_cpu_data->first_cpu = cpumask_first(policy->related_cpus);
+ parent_cpu_data->cur_freq = policy->cur;
+ parent_cpu_data->min_freq = policy->cpuinfo.min_freq;
+ parent_cpu_data->max_freq = policy->cpuinfo.max_freq;
+
+ list_add_tail(&parent_cpu_data->node, &p_data->cpu_data_list);
+ cpufreq_cpu_put(policy);
+ }
+
+ mutex_lock(&devfreq->lock);
+ ret = devfreq_update_target(devfreq, 0L);
+ mutex_unlock(&devfreq->lock);
+ if (ret)
+ dev_err(dev, "failed to update the frequency\n");
+
+ return ret;
+
+err_free_cpu_data:
+ kfree(parent_cpu_data);
+err_put_policy:
+ cpufreq_cpu_put(policy);
+err:
+
+ return ret;
+}
+
+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;
+ int ret = 0;
+
+ mutex_lock_nested(&devfreq->lock, SINGLE_DEPTH_NESTING);
+ switch (event) {
+ case DEVFREQ_PRECHANGE:
+ if (parent->previous_freq > freq)
+ ret = devfreq_update_target(devfreq, freq);
+
+ break;
+ case DEVFREQ_POSTCHANGE:
+ if (parent->previous_freq < freq)
+ ret = devfreq_update_target(devfreq, freq);
+ break;
+ }
+ mutex_unlock(&devfreq->lock);
+
+ if (ret < 0)
+ dev_warn(&devfreq->dev,
+ "failed to update devfreq using passive governor\n");
+
+ return NOTIFY_DONE;
+}
+
+static int devfreq_passive_unregister_notifier(struct devfreq *devfreq)
+{
+ 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;
+
+ return devfreq_unregister_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
+}
+
+static int devfreq_passive_register_notifier(struct devfreq *devfreq)
+{
+ 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;
+
+ if (!parent)
+ return -EPROBE_DEFER;
+
+ nb->notifier_call = devfreq_passive_notifier_call;
+ return devfreq_register_notifier(parent, nb, DEVFREQ_TRANSITION_NOTIFIER);
+}
+
+static int devfreq_passive_event_handler(struct devfreq *devfreq,
+ unsigned int event, void *data)
+{
+ struct devfreq_passive_data *p_data
+ = (struct devfreq_passive_data *)devfreq->data;
+ int ret = 0;
+
+ if (!p_data)
+ return -EINVAL;
+
+ p_data->this = devfreq;
+
+ switch (event) {
+ case DEVFREQ_GOV_START:
+ if (p_data->parent_type == DEVFREQ_PARENT_DEV)
+ ret = devfreq_passive_register_notifier(devfreq);
+ else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
+ ret = cpufreq_passive_register_notifier(devfreq);
+ break;
+ case DEVFREQ_GOV_STOP:
+ if (p_data->parent_type == DEVFREQ_PARENT_DEV)
+ WARN_ON(devfreq_passive_unregister_notifier(devfreq));
+ else if (p_data->parent_type == CPUFREQ_PARENT_DEV)
+ WARN_ON(cpufreq_passive_unregister_notifier(devfreq));
+ break;
+ default:
+ break;
+ }
+
+ return ret;
+}
+
+static struct devfreq_governor devfreq_passive = {
+ .name = DEVFREQ_GOV_PASSIVE,
+ .flags = DEVFREQ_GOV_FLAG_IMMUTABLE,
+ .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");