v4.19.13 snapshot.
diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
new file mode 100644
index 0000000..28e0f2d
--- /dev/null
+++ b/drivers/devfreq/governor_simpleondemand.c
@@ -0,0 +1,150 @@
+/*
+ * 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/module.h>
+#include <linux/devfreq.h>
+#include <linux/math64.h>
+#include "governor.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)
+{
+ int err;
+ struct devfreq_dev_status *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;
+ unsigned long max = (df->max_freq) ? df->max_freq : UINT_MAX;
+
+ err = devfreq_update_stats(df);
+ if (err)
+ return err;
+
+ stat = &df->last_status;
+
+ 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 = 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 = max;
+ return 0;
+ }
+
+ /* Set MAX if we do not know the initial frequency */
+ if (stat->current_frequency == 0) {
+ *freq = 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;
+
+ if (df->min_freq && *freq < df->min_freq)
+ *freq = df->min_freq;
+ if (df->max_freq && *freq > df->max_freq)
+ *freq = df->max_freq;
+
+ return 0;
+}
+
+static int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
+ unsigned int event, void *data)
+{
+ switch (event) {
+ case DEVFREQ_GOV_START:
+ devfreq_monitor_start(devfreq);
+ break;
+
+ case DEVFREQ_GOV_STOP:
+ devfreq_monitor_stop(devfreq);
+ break;
+
+ case DEVFREQ_GOV_INTERVAL:
+ devfreq_interval_update(devfreq, (unsigned int *)data);
+ break;
+
+ case DEVFREQ_GOV_SUSPEND:
+ devfreq_monitor_suspend(devfreq);
+ break;
+
+ case DEVFREQ_GOV_RESUME:
+ devfreq_monitor_resume(devfreq);
+ break;
+
+ default:
+ break;
+ }
+
+ return 0;
+}
+
+static struct devfreq_governor devfreq_simple_ondemand = {
+ .name = DEVFREQ_GOV_SIMPLE_ONDEMAND,
+ .get_target_freq = devfreq_simple_ondemand_func,
+ .event_handler = devfreq_simple_ondemand_handler,
+};
+
+static int __init devfreq_simple_ondemand_init(void)
+{
+ return devfreq_add_governor(&devfreq_simple_ondemand);
+}
+subsys_initcall(devfreq_simple_ondemand_init);
+
+static void __exit devfreq_simple_ondemand_exit(void)
+{
+ int ret;
+
+ ret = devfreq_remove_governor(&devfreq_simple_ondemand);
+ if (ret)
+ pr_err("%s: failed remove governor %d\n", __func__, ret);
+
+ return;
+}
+module_exit(devfreq_simple_ondemand_exit);
+MODULE_LICENSE("GPL");