linux-kernel - [PATCH 2/2] thermal: tegra-bpmp: Always (re)program trip temperatures

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Date:   Tue,  7 Feb 2023 15:56:09 +0200
From:   Mikko Perttunen <cyndis@...si.fi>
To:     "Rafael J. Wysocki" <rafael@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Amit Kucheria <amitk@...nel.org>,
        Zhang Rui <rui.zhang@...el.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Srikar Srimath Tirumala <srikars@...dia.com>
Cc:     Mikko Perttunen <mperttunen@...dia.com>,
        Timo Alho <talho@...dia.com>, linux-pm@...r.kernel.org,
        linux-tegra@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] thermal: tegra-bpmp: Always (re)program trip temperatures

From: Mikko Perttunen <mperttunen@...dia.com>

In the rare case that calculation of trip temperatures would result
in the same trip temperatures that were previously programmed, the
thermal core skips calling .set_trips. However, presently, if it is
not called, we may end up with no trip temperatures programmed at all.

To avoid this, make set_trips a no-op and in places where it would be
called, instead unconditionally program trip temperatures to the last
specified temperatures.

This also fixes the situation where a trip is triggered between
registering a thermal zone and registering the trip MRQ handler, in
which case we would also get stuck.

Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
---
 drivers/thermal/tegra/tegra-bpmp-thermal.c | 33 +++++++++++++++++++---
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/drivers/thermal/tegra/tegra-bpmp-thermal.c b/drivers/thermal/tegra/tegra-bpmp-thermal.c
index 628b18818ae9..9f69dbe1c7d4 100644
--- a/drivers/thermal/tegra/tegra-bpmp-thermal.c
+++ b/drivers/thermal/tegra/tegra-bpmp-thermal.c
@@ -67,9 +67,8 @@ static int tegra_bpmp_thermal_get_temp(struct thermal_zone_device *tz, int *out_
 	return __tegra_bpmp_thermal_get_temp(tz->devdata, out_temp);
 }
 
-static int tegra_bpmp_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
+static int tegra_bpmp_thermal_program_trips(struct tegra_bpmp_thermal_zone *zone)
 {
-	struct tegra_bpmp_thermal_zone *zone = tz->devdata;
 	struct mrq_thermal_host_to_bpmp_request req;
 	struct tegra_bpmp_message msg;
 	int err;
@@ -78,8 +77,10 @@ static int tegra_bpmp_thermal_set_trips(struct thermal_zone_device *tz, int low,
 	req.type = CMD_THERMAL_SET_TRIP;
 	req.set_trip.zone = zone->idx;
 	req.set_trip.enabled = true;
-	req.set_trip.low = low;
-	req.set_trip.high = high;
+	mutex_lock(&zone->tzd->lock);
+	req.set_trip.low = zone->tzd->prev_low_trip;
+	req.set_trip.high = zone->tzd->prev_high_trip;
+	mutex_unlock(&zone->tzd->lock);
 
 	memset(&msg, 0, sizeof(msg));
 	msg.mrq = MRQ_THERMAL;
@@ -95,14 +96,31 @@ static int tegra_bpmp_thermal_set_trips(struct thermal_zone_device *tz, int low,
 	return 0;
 }
 
+static int tegra_bpmp_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
+{
+	return 0;
+}
+
 static void tz_device_update_work_fn(struct work_struct *work)
 {
 	struct tegra_bpmp_thermal_zone *zone;
+	int err;
 
 	zone = container_of(work, struct tegra_bpmp_thermal_zone,
 			    tz_device_update_work);
 
+	/* Recalculates trip temperatures. */
 	thermal_zone_device_update(zone->tzd, THERMAL_TRIP_VIOLATED);
+
+	/*
+	 * Program trip temperatures. We must do this outside `set_trips`
+	 * since thermal core may skip calling it if the trip temperatures
+	 * are unchanged.
+	 */
+	err = tegra_bpmp_thermal_program_trips(zone);
+	if (err)
+		dev_err(zone->tegra->dev, "failed to update trip temperatures for zone '%s': %d\n",
+			zone->tzd->type, err);
 }
 
 static void bpmp_mrq_thermal(unsigned int mrq, struct tegra_bpmp_channel *ch,
@@ -293,6 +311,13 @@ static int tegra_bpmp_thermal_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	for (i = 0; i < tegra->num_zones; i++) {
+		err = tegra_bpmp_thermal_program_trips(tegra->zones[i]);
+		if (err)
+			dev_err(&pdev->dev, "failed to set trip temperatures for zone '%s': %d\n",
+				tzd->type, err);
+	}
+
 	platform_set_drvdata(pdev, tegra);
 
 	return 0;
-- 
2.39.0