cpufreq: interactive: specify duration of CPU speed boost pulse

Sysfs attribute boostpulse_duration specifies the duration of boosting CPU
speed in response to bootpulse events.  Duration is specified in usecs,
default 80ms.

Change-Id: Ifd41625574891a44f1787a4e85d1e7b4f2afb52b
Signed-off-by: Todd Poynor <toddpoynor@google.com>

drivers/cpufreq/cpufreq_interactive.c

@@ -95,11 +95,12 @@ static unsigned long timer_rate;
 #define DEFAULT_ABOVE_HISPEED_DELAY DEFAULT_TIMER_RATE
 static unsigned long above_hispeed_delay_val;
 
-/*
+/* Non-zero means indefinite speed boost active */
- * Non-zero means longer-term speed boost active.
- */
-
 static int boost_val;
+/* Duration of a boot pulse in usecs */
+static int boostpulse_duration_val = DEFAULT_MIN_SAMPLE_TIME;
+/* End time of boost pulse in ktime converted to usecs */
+static u64 boostpulse_endtime;
 
 static bool governidle;
 module_param(governidle, bool, S_IWUSR | S_IRUGO);
@@ -268,6 +269,7 @@ static void cpufreq_interactive_timer(unsigned long data)
 	unsigned int loadadjfreq;
 	unsigned int index;
 	unsigned long flags;
+	bool boosted;
 
 	smp_rmb();
 
@@ -286,8 +288,9 @@ static void cpufreq_interactive_timer(unsigned long data)
 	do_div(cputime_speedadj, delta_time);
 	loadadjfreq = (unsigned int)cputime_speedadj * 100;
 	cpu_load = loadadjfreq / pcpu->target_freq;
+	boosted = boost_val || now < boostpulse_endtime;
 
-	if ((cpu_load >= go_hispeed_load || boost_val) &&
+	if ((cpu_load >= go_hispeed_load || boosted) &&
 	    pcpu->target_freq < hispeed_freq)
 		new_freq = hispeed_freq;
 	else
@@ -327,8 +330,18 @@ static void cpufreq_interactive_timer(unsigned long data)
 		}
 	}
 
-	pcpu->floor_freq = new_freq;
+	/*
-	pcpu->floor_validate_time = now;
+	 * Update the timestamp for checking whether speed has been held at
+	 * or above the selected frequency for a minimum of min_sample_time,
+	 * if not boosted to hispeed_freq.  If boosted to hispeed_freq then we
+	 * allow the speed to drop as soon as the boostpulse duration expires
+	 * (or the indefinite boost is turned off).
+	 */
+
+	if (!boosted || new_freq > hispeed_freq) {
+		pcpu->floor_freq = new_freq;
+		pcpu->floor_validate_time = now;
+	}
 
 	if (pcpu->target_freq == new_freq) {
 		trace_cpufreq_interactive_already(
@@ -774,6 +787,7 @@ static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 	if (ret < 0)
 		return ret;
 
+	boostpulse_endtime = ktime_to_us(ktime_get()) + boostpulse_duration_val;
 	trace_cpufreq_interactive_boost("pulse");
 	cpufreq_interactive_boost();
 	return count;
@@ -782,6 +796,29 @@ static ssize_t store_boostpulse(struct kobject *kobj, struct attribute *attr,
 static struct global_attr boostpulse =
 	__ATTR(boostpulse, 0200, NULL, store_boostpulse);
 
+static ssize_t show_boostpulse_duration(
+	struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", boostpulse_duration_val);
+}
+
+static ssize_t store_boostpulse_duration(
+	struct kobject *kobj, struct attribute *attr, const char *buf,
+	size_t count)
+{
+	int ret;
+	unsigned long val;
+
+	ret = kstrtoul(buf, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	boostpulse_duration_val = val;
+	return count;
+}
+
+define_one_global_rw(boostpulse_duration);
+
 static struct attribute *interactive_attributes[] = {
 	&target_loads_attr.attr,
 	&hispeed_freq_attr.attr,
@@ -791,6 +828,7 @@ static struct attribute *interactive_attributes[] = {
 	&timer_rate_attr.attr,
 	&boost.attr,
 	&boostpulse.attr,
+	&boostpulse_duration.attr,
 	NULL,
 };