[PATCH v5] drivers: thermal: clear all mitigation when thermal zone is disabled

* [PATCH v5] drivers: thermal: clear all mitigation when thermal zone is disabled
@ 2022-01-27 18:11 Manaf Meethalavalappu Pallikunhi
  2022-01-31  7:25 ` Lukasz Luba
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Manaf Meethalavalappu Pallikunhi @ 2022-01-27 18:11 UTC (permalink / raw)
  To: Lukasz Luba, Rafael J . Wysocki, Daniel Lezcano, Amit Kucheria,
	Zhang Rui
  Cc: linux-pm, linux-kernel, Manaf Meethalavalappu Pallikunhi

Whenever a thermal zone is in trip violated state, there is a chance
that the same thermal zone mode can be disabled either via
thermal core API or via thermal zone sysfs. Once it is disabled,
the framework bails out any re-evaluation of thermal zone. It leads
to a case where if it is already in mitigation state, it will stay
the same state forever.

To avoid above mentioned issue, add support to bind/unbind
governor from thermal zone during thermal zone mode change request
and clear all existing throttling in governor unbind_from_tz()
callback.

Suggested-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Manaf Meethalavalappu Pallikunhi <quic_manafm@quicinc.com>
---
 drivers/thermal/gov_power_allocator.c |  3 +++
 drivers/thermal/gov_step_wise.c       | 26 ++++++++++++++++++++++++++
 drivers/thermal/thermal_core.c        | 31 +++++++++++++++++++++++++++----
 3 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/gov_power_allocator.c b/drivers/thermal/gov_power_allocator.c
index 13e3757..9ff0c5f 100644
--- a/drivers/thermal/gov_power_allocator.c
+++ b/drivers/thermal/gov_power_allocator.c
@@ -696,6 +696,9 @@ static void power_allocator_unbind(struct thermal_zone_device *tz)
 
 	dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);
 
+	tz->passive = 0;
+	allow_maximum_power(tz, true);
+
 	if (params->allocated_tzp) {
 		kfree(tz->tzp);
 		tz->tzp = NULL;
diff --git a/drivers/thermal/gov_step_wise.c b/drivers/thermal/gov_step_wise.c
index 12acb12..2d2186b 100644
--- a/drivers/thermal/gov_step_wise.c
+++ b/drivers/thermal/gov_step_wise.c
@@ -168,6 +168,31 @@ static void thermal_zone_trip_update(struct thermal_zone_device *tz, int trip)
 }
 
 /**
+ * step_wise_unbind() - unbind the step_wise governor to a thermal zone
+ * @tz:	thermal zone to unbind it to
+ *
+ * Clear all previous throttling and reset passive counter.
+ *
+ */
+static void step_wise_unbind(struct thermal_zone_device *tz)
+{
+	struct thermal_instance *instance;
+
+	dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);
+
+	mutex_lock(&tz->lock);
+	tz->passive = 0;
+	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {
+		instance->initialized = false;
+		instance->target = THERMAL_NO_TARGET;
+		mutex_lock(&instance->cdev->lock);
+		__thermal_cdev_update(instance->cdev);
+		mutex_unlock(&instance->cdev->lock);
+	}
+	mutex_unlock(&tz->lock);
+}
+
+/**
  * step_wise_throttle - throttles devices associated with the given zone
  * @tz: thermal_zone_device
  * @trip: trip point index
@@ -196,6 +221,7 @@ static int step_wise_throttle(struct thermal_zone_device *tz, int trip)
 
 static struct thermal_governor thermal_gov_step_wise = {
 	.name		= "step_wise",
+	.unbind_from_tz	= step_wise_unbind,
 	.throttle	= step_wise_throttle,
 };
 THERMAL_GOVERNOR_DECLARE(thermal_gov_step_wise);
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 82654dc..34726d3 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -274,6 +274,26 @@ static int __init thermal_register_governors(void)
 	return ret;
 }
 
+static void thermal_governor_attach(struct thermal_zone_device *tz)
+{
+	mutex_lock(&thermal_governor_lock);
+	if (tz->governor && tz->governor->bind_to_tz) {
+		if (tz->governor->bind_to_tz(tz))
+			dev_err(&tz->device,
+				"governor %s failed to bind to thermal zone %s\n",
+				tz->governor->name, tz->type);
+	}
+	mutex_unlock(&thermal_governor_lock);
+}
+
+static void thermal_governor_detach(struct thermal_zone_device *tz)
+{
+	mutex_lock(&thermal_governor_lock);
+	if (tz->governor && tz->governor->unbind_from_tz)
+		tz->governor->unbind_from_tz(tz);
+	mutex_unlock(&thermal_governor_lock);
+}
+
 /*
  * Zone update section: main control loop applied to each zone while monitoring
  *
@@ -449,12 +469,15 @@ static int thermal_zone_device_set_mode(struct thermal_zone_device *tz,
 
 	mutex_unlock(&tz->lock);
 
-	thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
-
-	if (mode == THERMAL_DEVICE_ENABLED)
+	if (mode == THERMAL_DEVICE_ENABLED) {
+		thermal_governor_attach(tz);
+		thermal_zone_device_init(tz);
+		thermal_zone_device_update(tz, THERMAL_EVENT_UNSPECIFIED);
 		thermal_notify_tz_enable(tz->id);
-	else
+	} else {
+		thermal_governor_detach(tz);
 		thermal_notify_tz_disable(tz->id);
+	}
 
 	return ret;
 }

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