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");