@@ -64,6 +64,15 @@ config DEVFREQ_GOV_USERSPACE
Otherwise, the governor does not change the frequnecy
given at the initialization.
+config DEVFREQ_GOV_PASSIVE
+ tristate "Passive"
+ help
+ Sets the frequency by other governors (simple_ondemand, performance,
+ powersave, usersapce) of a parent devfreq device. This governor
+ always has the dependency on the chosen frequency from paired
+ governor. This governor does not change the frequency by oneself
+ through sysfs entry.
+
comment "DEVFREQ Drivers"
config ARM_EXYNOS_BUS_DEVFREQ
@@ -4,6 +4,7 @@ obj-$(CONFIG_DEVFREQ_GOV_SIMPLE_ONDEMAND) += governor_simpleondemand.o
obj-$(CONFIG_DEVFREQ_GOV_PERFORMANCE) += governor_performance.o
obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE) += governor_powersave.o
obj-$(CONFIG_DEVFREQ_GOV_USERSPACE) += governor_userspace.o
+obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
# DEVFREQ Drivers
obj-$(CONFIG_ARCH_EXYNOS) += exynos/
@@ -190,6 +190,31 @@ static struct devfreq_governor *find_devfreq_governor(const char *name)
/* Load monitoring helper functions for governors use */
+static int update_devfreq_passive(struct devfreq *devfreq, unsigned long freq)
+{
+ struct devfreq *passive;
+ unsigned long rate;
+ int ret;
+
+ list_for_each_entry(passive, &devfreq->passive_dev_list, passive_node) {
+ if (!passive->governor)
+ continue;
+ rate = freq;
+
+ ret = passive->governor->get_target_freq(passive, &rate);
+ if (ret)
+ return ret;
+
+ ret = passive->profile->target(passive->dev.parent, &rate, 0);
+ if (ret)
+ return ret;
+
+ passive->previous_freq = rate;
+ }
+
+ return 0;
+}
+
/**
* update_devfreq() - Reevaluate the device and configure frequency.
* @devfreq: the devfreq instance.
@@ -233,10 +258,18 @@ int update_devfreq(struct devfreq *devfreq)
flags |= DEVFREQ_FLAG_LEAST_UPPER_BOUND; /* Use LUB */
}
+ if (!list_empty(&devfreq->passive_dev_list)
+ && devfreq->previous_freq > freq)
+ update_devfreq_passive(devfreq, freq);
+
err = devfreq->profile->target(devfreq->dev.parent, &freq, flags);
if (err)
return err;
+ if (!list_empty(&devfreq->passive_dev_list)
+ && devfreq->previous_freq < freq)
+ update_devfreq_passive(devfreq, freq);
+
if (devfreq->profile->freq_table)
if (devfreq_update_status(devfreq, freq))
dev_err(&devfreq->dev,
@@ -442,6 +475,10 @@ static void _remove_devfreq(struct devfreq *devfreq)
return;
}
list_del(&devfreq->node);
+ list_del(&devfreq->passive_node);
+ if (!list_empty(&devfreq->passive_dev_list))
+ list_del_init(&devfreq->passive_dev_list);
+
mutex_unlock(&devfreq_list_lock);
if (devfreq->governor)
@@ -559,6 +596,16 @@ struct devfreq *devfreq_add_device(struct device *dev,
goto err_init;
}
+ if (!strncmp(devfreq->governor_name, "passive", 7)) {
+ struct devfreq *parent_devfreq =
+ ((struct devfreq_passive_data *)data)->parent;
+
+ list_add(&devfreq->passive_node,
+ &parent_devfreq->passive_dev_list);
+ } else {
+ INIT_LIST_HEAD(&devfreq->passive_dev_list);
+ }
+
return devfreq;
err_init:
new file mode 100644
@@ -0,0 +1,108 @@
+/*
+ * linux/drivers/devfreq/governor_passive.c
+ *
+ * Copyright (C) 2015 Samsung Electronics
+ * Author: Chanwoo Choi <cw00.choi@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/devfreq.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/devfreq.h>
+#include "governor.h"
+
+static int devfreq_passive_get_target_freq(struct devfreq *passive,
+ unsigned long *freq)
+{
+ struct devfreq_passive_data *passive_data = passive->data;
+ struct devfreq *parent_devfreq = passive_data->parent;
+ unsigned long child_freq = ULONG_MAX;
+ int i, count;
+
+ /*
+ * Each devfreq has the OPP table. After deciding the new frequency
+ * from the governor of parent devfreq device, the passive governor
+ * need to get the index of new frequency on OPP table of parent
+ * device. And then the index is used for getting the suitable
+ * new frequency for passive devfreq device.
+ */
+
+ if (!passive->profile || !passive->profile->freq_table
+ || passive->profile->max_state <= 0)
+ return -EINVAL;
+
+ /*
+ * When new frequency is lower than previous frequency of parent
+ * devfreq device, passive governor get the correct frequency from OPP
+ * list of parent device. Because in this case, *freq is temporary
+ * value which is decided by ondemand governor.
+ */
+ if (parent_devfreq->previous_freq > *freq) {
+ struct dev_pm_opp *opp;
+ opp = devfreq_recommended_opp(parent_devfreq->dev.parent,
+ freq, 0);
+ if (IS_ERR_OR_NULL(opp))
+ return PTR_ERR(opp);
+ }
+
+ /*
+ * Get the OPP table's index of decided freqeuncy by governor
+ * of parent device.
+ */
+ for (i = 0; i < parent_devfreq->profile->max_state; i++)
+ if (parent_devfreq->profile->freq_table[i] == *freq)
+ break;
+
+ if (i == parent_devfreq->profile->max_state)
+ return -EINVAL;
+ count = passive->profile->max_state;
+
+ /* Get the suitable frequency by using index of parent device. */
+ if (i < passive->profile->max_state)
+ child_freq = passive->profile->freq_table[i];
+ else
+ child_freq = passive->profile->freq_table[count - 1];
+
+ /* Return the suitable frequency for passive device. */
+ *freq = child_freq;
+
+ return 0;
+}
+
+static int devfreq_passive_event_handler(struct devfreq *devfreq,
+ unsigned int event, void *data)
+{
+ return 0;
+}
+
+static struct devfreq_governor devfreq_passive = {
+ .name = "passive",
+ .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);
+
+ return;
+}
+module_exit(devfreq_passive_exit);
+
+MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
+MODULE_DESCRIPTION("DEVFREQ Passive governor");
+MODULE_LICENSE("GPL v2");
@@ -177,6 +177,9 @@ struct devfreq {
unsigned int *trans_table;
unsigned long *time_in_state;
unsigned long last_stat_updated;
+
+ struct list_head passive_dev_list;
+ struct list_head passive_node;
};
#if defined(CONFIG_PM_DEVFREQ)
@@ -241,6 +244,18 @@ struct devfreq_simple_ondemand_data {
};
#endif
+/**
+ * struct devfreq_passive_data - void *data fed to struct devfreq
+ * and devfreq_add_device
+ * @parent: The parent devfreq device.
+ *
+ * If the fed devfreq_passive_data pointer is NULL to the governor,
+ * the governor return ERROR.
+ */
+struct devfreq_passive_data {
+ struct devfreq *parent;
+};
+
#else /* !CONFIG_PM_DEVFREQ */
static inline struct devfreq *devfreq_add_device(struct device *dev,
struct devfreq_dev_profile *profile,