cpufreq: interactive: Separate speed target revalidate time and initial set time

Allow speed drop after min_sample_time elapses from last time
the current speed was last re-validated as appropriate for
current load / input boost.

Allow speed bump after min_sample_time (or above_hispeed_delay)
elapses from the time the current speed was originally set.

Change-Id: Ic25687a7a53d25e6544c30c47d7ab6f27a47bee8
Signed-off-by: Todd Poynor <toddpoynor@google.com>
diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 748e55b..0ef53e9 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -45,6 +45,8 @@
 	int idling;
 	u64 target_set_time;
 	u64 target_set_time_in_idle;
+	u64 target_validate_time;
+	u64 target_validate_time_in_idle;
 	struct cpufreq_policy *policy;
 	struct cpufreq_frequency_table *freq_table;
 	unsigned int target_freq;
@@ -207,10 +209,10 @@
 
 	/*
 	 * Do not scale down unless we have been at this frequency for the
-	 * minimum sample time.
+	 * minimum sample time since last validated.
 	 */
 	if (new_freq < pcpu->target_freq) {
-		if (pcpu->timer_run_time - pcpu->target_set_time
+		if (pcpu->timer_run_time - pcpu->target_validate_time
 		    < min_sample_time) {
 			trace_cpufreq_interactive_notyet(data, cpu_load,
 					 pcpu->target_freq, new_freq);
@@ -218,8 +220,8 @@
 		}
 	}
 
-	pcpu->target_set_time_in_idle = now_idle;
-	pcpu->target_set_time = pcpu->timer_run_time;
+	pcpu->target_validate_time_in_idle = now_idle;
+	pcpu->target_validate_time = pcpu->timer_run_time;
 
 	if (pcpu->target_freq == new_freq) {
 		trace_cpufreq_interactive_already(data, cpu_load,
@@ -229,6 +231,8 @@
 
 	trace_cpufreq_interactive_target(data, cpu_load, pcpu->target_freq,
 					 new_freq);
+	pcpu->target_set_time_in_idle = now_idle;
+	pcpu->target_set_time = pcpu->timer_run_time;
 
 	if (new_freq < pcpu->target_freq) {
 		pcpu->target_freq = new_freq;
@@ -613,6 +617,10 @@
 			pcpu->target_set_time_in_idle =
 				get_cpu_idle_time_us(j,
 					     &pcpu->target_set_time);
+			pcpu->target_validate_time =
+				pcpu->target_set_time;
+			pcpu->target_validate_time_in_idle =
+				pcpu->target_set_time_in_idle;
 			pcpu->governor_enabled = 1;
 			smp_wmb();
 		}