aboutsummaryrefslogtreecommitdiff
path: root/drivers/devfreq
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/devfreq')
-rw-r--r--drivers/devfreq/Kconfig36
-rw-r--r--drivers/devfreq/Makefile4
-rw-r--r--drivers/devfreq/governor_performance.c29
-rw-r--r--drivers/devfreq/governor_powersave.c29
-rw-r--r--drivers/devfreq/governor_simpleondemand.c88
-rw-r--r--drivers/devfreq/governor_userspace.c116
6 files changed, 302 insertions, 0 deletions
diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
index 1fb42de4f42..643b055ed3c 100644
--- a/drivers/devfreq/Kconfig
+++ b/drivers/devfreq/Kconfig
@@ -34,6 +34,42 @@ menuconfig PM_DEVFREQ
if PM_DEVFREQ
+comment "DEVFREQ Governors"
+
+config DEVFREQ_GOV_SIMPLE_ONDEMAND
+ bool "Simple Ondemand"
+ help
+ Chooses frequency based on the recent load on the device. Works
+ similar as ONDEMAND governor of CPUFREQ does. A device with
+ Simple-Ondemand should be able to provide busy/total counter
+ values that imply the usage rate. A device may provide tuned
+ values to the governor with data field at devfreq_add_device().
+
+config DEVFREQ_GOV_PERFORMANCE
+ bool "Performance"
+ help
+ Sets the frequency at the maximum available frequency.
+ This governor always returns UINT_MAX as frequency so that
+ the DEVFREQ framework returns the highest frequency available
+ at any time.
+
+config DEVFREQ_GOV_POWERSAVE
+ bool "Powersave"
+ help
+ Sets the frequency at the minimum available frequency.
+ This governor always returns 0 as frequency so that
+ the DEVFREQ framework returns the lowest frequency available
+ at any time.
+
+config DEVFREQ_GOV_USERSPACE
+ bool "Userspace"
+ help
+ Sets the frequency at the user specified one.
+ This governor returns the user configured frequency if there
+ has been an input to /sys/devices/.../power/devfreq_set_freq.
+ Otherwise, the governor does not change the frequnecy
+ given at the initialization.
+
comment "DEVFREQ Drivers"
endif # PM_DEVFREQ
diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
index 168934a12b3..4564a89e970 100644
--- a/drivers/devfreq/Makefile
+++ b/drivers/devfreq/Makefile
@@ -1 +1,5 @@
obj-$(CONFIG_PM_DEVFREQ) += devfreq.o
+obj-$(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
diff --git a/drivers/devfreq/governor_performance.c b/drivers/devfreq/governor_performance.c
new file mode 100644
index 00000000000..c0596b29176
--- /dev/null
+++ b/drivers/devfreq/governor_performance.c
@@ -0,0 +1,29 @@
+/*
+ * linux/drivers/devfreq/governor_performance.c
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@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>
+
+static int devfreq_performance_func(struct devfreq *df,
+ unsigned long *freq)
+{
+ /*
+ * target callback should be able to get floor value as
+ * said in devfreq.h
+ */
+ *freq = UINT_MAX;
+ return 0;
+}
+
+const struct devfreq_governor devfreq_performance = {
+ .name = "performance",
+ .get_target_freq = devfreq_performance_func,
+ .no_central_polling = true,
+};
diff --git a/drivers/devfreq/governor_powersave.c b/drivers/devfreq/governor_powersave.c
new file mode 100644
index 00000000000..2483a85a266
--- /dev/null
+++ b/drivers/devfreq/governor_powersave.c
@@ -0,0 +1,29 @@
+/*
+ * linux/drivers/devfreq/governor_powersave.c
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@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>
+
+static int devfreq_powersave_func(struct devfreq *df,
+ unsigned long *freq)
+{
+ /*
+ * target callback should be able to get ceiling value as
+ * said in devfreq.h
+ */
+ *freq = 0;
+ return 0;
+}
+
+const struct devfreq_governor devfreq_powersave = {
+ .name = "powersave",
+ .get_target_freq = devfreq_powersave_func,
+ .no_central_polling = true,
+};
diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
new file mode 100644
index 00000000000..efad8dcf902
--- /dev/null
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -0,0 +1,88 @@
+/*
+ * linux/drivers/devfreq/governor_simpleondemand.c
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@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/errno.h>
+#include <linux/devfreq.h>
+#include <linux/math64.h>
+
+/* Default constants for DevFreq-Simple-Ondemand (DFSO) */
+#define DFSO_UPTHRESHOLD (90)
+#define DFSO_DOWNDIFFERENCTIAL (5)
+static int devfreq_simple_ondemand_func(struct devfreq *df,
+ unsigned long *freq)
+{
+ struct devfreq_dev_status stat;
+ int err = df->profile->get_dev_status(df->dev.parent, &stat);
+ unsigned long long a, b;
+ unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
+ unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
+ struct devfreq_simple_ondemand_data *data = df->data;
+
+ if (err)
+ return err;
+
+ if (data) {
+ if (data->upthreshold)
+ dfso_upthreshold = data->upthreshold;
+ if (data->downdifferential)
+ dfso_downdifferential = data->downdifferential;
+ }
+ if (dfso_upthreshold > 100 ||
+ dfso_upthreshold < dfso_downdifferential)
+ return -EINVAL;
+
+ /* Assume MAX if it is going to be divided by zero */
+ if (stat.total_time == 0) {
+ *freq = UINT_MAX;
+ return 0;
+ }
+
+ /* Prevent overflow */
+ if (stat.busy_time >= (1 << 24) || stat.total_time >= (1 << 24)) {
+ stat.busy_time >>= 7;
+ stat.total_time >>= 7;
+ }
+
+ /* Set MAX if it's busy enough */
+ if (stat.busy_time * 100 >
+ stat.total_time * dfso_upthreshold) {
+ *freq = UINT_MAX;
+ return 0;
+ }
+
+ /* Set MAX if we do not know the initial frequency */
+ if (stat.current_frequency == 0) {
+ *freq = UINT_MAX;
+ return 0;
+ }
+
+ /* Keep the current frequency */
+ if (stat.busy_time * 100 >
+ stat.total_time * (dfso_upthreshold - dfso_downdifferential)) {
+ *freq = stat.current_frequency;
+ return 0;
+ }
+
+ /* Set the desired frequency based on the load */
+ a = stat.busy_time;
+ a *= stat.current_frequency;
+ b = div_u64(a, stat.total_time);
+ b *= 100;
+ b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
+ *freq = (unsigned long) b;
+
+ return 0;
+}
+
+const struct devfreq_governor devfreq_simple_ondemand = {
+ .name = "simple_ondemand",
+ .get_target_freq = devfreq_simple_ondemand_func,
+};
diff --git a/drivers/devfreq/governor_userspace.c b/drivers/devfreq/governor_userspace.c
new file mode 100644
index 00000000000..4f8b563da78
--- /dev/null
+++ b/drivers/devfreq/governor_userspace.c
@@ -0,0 +1,116 @@
+/*
+ * linux/drivers/devfreq/governor_simpleondemand.c
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@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/slab.h>
+#include <linux/device.h>
+#include <linux/devfreq.h>
+#include <linux/pm.h>
+#include <linux/mutex.h>
+#include "governor.h"
+
+struct userspace_data {
+ unsigned long user_frequency;
+ bool valid;
+};
+
+static int devfreq_userspace_func(struct devfreq *df, unsigned long *freq)
+{
+ struct userspace_data *data = df->data;
+
+ if (!data->valid)
+ *freq = df->previous_freq; /* No user freq specified yet */
+ else
+ *freq = data->user_frequency;
+ return 0;
+}
+
+static ssize_t store_freq(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct devfreq *devfreq = to_devfreq(dev);
+ struct userspace_data *data;
+ unsigned long wanted;
+ int err = 0;
+
+
+ mutex_lock(&devfreq->lock);
+ data = devfreq->data;
+
+ sscanf(buf, "%lu", &wanted);
+ data->user_frequency = wanted;
+ data->valid = true;
+ err = update_devfreq(devfreq);
+ if (err == 0)
+ err = count;
+ mutex_unlock(&devfreq->lock);
+ return err;
+}
+
+static ssize_t show_freq(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct devfreq *devfreq = to_devfreq(dev);
+ struct userspace_data *data;
+ int err = 0;
+
+ mutex_lock(&devfreq->lock);
+ data = devfreq->data;
+
+ if (data->valid)
+ err = sprintf(buf, "%lu\n", data->user_frequency);
+ else
+ err = sprintf(buf, "undefined\n");
+ mutex_unlock(&devfreq->lock);
+ return err;
+}
+
+static DEVICE_ATTR(set_freq, 0644, show_freq, store_freq);
+static struct attribute *dev_entries[] = {
+ &dev_attr_set_freq.attr,
+ NULL,
+};
+static struct attribute_group dev_attr_group = {
+ .name = "userspace",
+ .attrs = dev_entries,
+};
+
+static int userspace_init(struct devfreq *devfreq)
+{
+ int err = 0;
+ struct userspace_data *data = kzalloc(sizeof(struct userspace_data),
+ GFP_KERNEL);
+
+ if (!data) {
+ err = -ENOMEM;
+ goto out;
+ }
+ data->valid = false;
+ devfreq->data = data;
+
+ err = sysfs_create_group(&devfreq->dev.kobj, &dev_attr_group);
+out:
+ return err;
+}
+
+static void userspace_exit(struct devfreq *devfreq)
+{
+ sysfs_remove_group(&devfreq->dev.kobj, &dev_attr_group);
+ kfree(devfreq->data);
+ devfreq->data = NULL;
+}
+
+const struct devfreq_governor devfreq_userspace = {
+ .name = "userspace",
+ .get_target_freq = devfreq_userspace_func,
+ .init = userspace_init,
+ .exit = userspace_exit,
+ .no_central_polling = true,
+};
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-24 02:22:56 +0000