From: Hyeonseong Gil <hs.gil@samsung.com>
Date: Wed, 4 May 2016 07:43:48 +0000 (+0900)
Subject: [COMMON] thermal: power_allocator: anti-windup for integral term
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=c7e3357cc27c8ba22a077afbaf20c155291ad7c6;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

[COMMON] thermal: power_allocator: anti-windup for integral term

Change-Id: Id62b77cc74dc69c9d54a43574d732c5bb16b1535
Signed-off-by: Hyeonseong Gil <hs.gil@samsung.com>
---

diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index 548b325e7c48..11617dc4e769 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -1032,6 +1032,9 @@ int __init of_parse_thermal_zones(void)
 		if (!of_property_read_u32(child, "k_i", &prop))
 			tzp->k_i = prop;
 
+		if (!of_property_read_u32(child, "i_max", &prop))
+			tzp->integral_max = prop;
+
 		for (i = 0; i < tz->ntrips; i++)
 			mask |= 1 << i;
 
diff --git a/drivers/thermal/power_allocator.c b/drivers/thermal/power_allocator.c
index 9e0f02427b10..40debd67bf68 100644
--- a/drivers/thermal/power_allocator.c
+++ b/drivers/thermal/power_allocator.c
@@ -158,13 +158,20 @@ static void estimate_pid_constants(struct thermal_zone_device *tz,
 	if (!tz->tzp->k_po || force)
 		tz->tzp->k_po = int_to_frac(sustainable_power) /
 			temperature_threshold;
+	else
+		tz->tzp->k_po = int_to_frac(tz->tzp->k_po);
 
 	if (!tz->tzp->k_pu || force)
 		tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /
 			temperature_threshold;
+	else
+		tz->tzp->k_pu = int_to_frac(tz->tzp->k_pu);
 
 	if (!tz->tzp->k_i || force)
 		tz->tzp->k_i = int_to_frac(10) / 1000;
+	else
+		tz->tzp->k_i = int_to_frac(tz->tzp->k_i);
+
 	/*
 	 * The default for k_d and integral_cutoff is 0, so we can
 	 * leave them as they are.
@@ -209,7 +216,7 @@ static u32 pid_controller(struct thermal_zone_device *tz,
 				       true);
 	}
 
-	err = control_temp - tz->temperature;
+	err = (control_temp - tz->temperature) / 1000;
 	err = int_to_frac(err);
 
 	/* Calculate the proportional term */
@@ -225,8 +232,15 @@ static u32 pid_controller(struct thermal_zone_device *tz,
 
 	if (err < int_to_frac(tz->tzp->integral_cutoff)) {
 		s64 i_next = i + mul_frac(tz->tzp->k_i, err);
-
-		if (abs(i_next) < max_power_frac) {
+		s64 i_windup = int_to_frac(-1 * (s64)tz->tzp->sustainable_power);
+
+		if (i_next > int_to_frac(tz->tzp->integral_max)) {
+			i = int_to_frac(tz->tzp->integral_max);
+			params->err_integral = div_frac(i, tz->tzp->k_i);
+		} else if (i_next <= i_windup) {
+			i = i_windup;
+			params->err_integral = div_frac(i, tz->tzp->k_i);
+		} else {
 			i = i_next;
 			params->err_integral += err;
 		}
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index a85b78ed4b6c..f969b5e790e1 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -333,6 +333,8 @@ struct thermal_zone_params {
 	/* threshold below which the error is no longer accumulated */
 	s32 integral_cutoff;
 
+	s32 integral_max;
+
 	/*
 	 * @slope:	slope of a linear temperature adjustment curve.
 	 * 		Used by thermal zone drivers.