[v9,03/10] thermal: Use generic HW-protection shutdown API

Message ID 85d0225cd0e287ec9a7b43709400794c5cf470d5.1620645507.git.matti.vaittinen@fi.rohmeurope.com
State Superseded
Headers show
  • Extend regulator notification support
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Commit Message

Vaittinen, Matti May 10, 2021, 11:29 a.m.
The hardware shutdown function was exported from kernel/reboot for
other subsystems to use. Logic is copied from the thermal_core. The
protection mutex is replaced by an atomic_t to allow calls also from
an IRQ context.

Use the exported API instead of implementing own just for the

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

 - Update the thermal documentation
 - new patch (change added in v7, splitted in own patch at v8)

Use the exported API instead
 .../driver-api/thermal/sysfs-api.rst          | 24 +++----
 drivers/thermal/thermal_core.c                | 63 ++-----------------
 2 files changed, 13 insertions(+), 74 deletions(-)


diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
index 4b638c14bc16..c93fa5e961a0 100644
--- a/Documentation/driver-api/thermal/sysfs-api.rst
+++ b/Documentation/driver-api/thermal/sysfs-api.rst
@@ -740,21 +740,15 @@  possible.
 5. thermal_emergency_poweroff
-On an event of critical trip temperature crossing. Thermal framework
-allows the system to shutdown gracefully by calling orderly_poweroff().
-In the event of a failure of orderly_poweroff() to shut down the system
-we are in danger of keeping the system alive at undesirably high
-temperatures. To mitigate this high risk scenario we program a work
-queue to fire after a pre-determined number of seconds to start
-an emergency shutdown of the device using the kernel_power_off()
-function. In case kernel_power_off() fails then finally
-emergency_restart() is called in the worst case.
+On an event of critical trip temperature crossing the thermal framework
+shuts down the system by calling hw_protection_shutdown(). The
+hw_protection_shutdown() first attempts to perform an orderly shutdown
+but accepts a delay after which it proceeds doing a forced power-off
+or as last resort an emergency_restart.
 The delay should be carefully profiled so as to give adequate time for
-orderly_poweroff(). In case of failure of an orderly_poweroff() the
-emergency poweroff kicks in after the delay has elapsed and shuts down
-the system.
+orderly poweroff.
-If set to 0 emergency poweroff will not be supported. So a carefully
-profiled non-zero positive value is a must for emergency poweroff to be
+If the delay is set to 0 emergency poweroff will not be supported. So a
+carefully profiled non-zero positive value is a must for emergency
+poweroff to be triggered.
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index d20b25f40d19..10a2d8e1cacf 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -36,10 +36,8 @@  static LIST_HEAD(thermal_governor_list);
 static DEFINE_MUTEX(thermal_list_lock);
 static DEFINE_MUTEX(thermal_governor_lock);
-static DEFINE_MUTEX(poweroff_lock);
 static atomic_t in_suspend;
-static bool power_off_triggered;
 static struct thermal_governor *def_governor;
@@ -327,70 +325,18 @@  static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip)
 		       def_governor->throttle(tz, trip);
- * thermal_emergency_poweroff_func - emergency poweroff work after a known delay
- * @work: work_struct associated with the emergency poweroff function
- *
- * This function is called in very critical situations to force
- * a kernel poweroff after a configurable timeout value.
- */
-static void thermal_emergency_poweroff_func(struct work_struct *work)
-	/*
-	 * We have reached here after the emergency thermal shutdown
-	 * Waiting period has expired. This means orderly_poweroff has
-	 * not been able to shut off the system for some reason.
-	 * Try to shut down the system immediately using kernel_power_off
-	 * if populated
-	 */
-	WARN(1, "Attempting kernel_power_off: Temperature too high\n");
-	kernel_power_off();
-	/*
-	 * Worst of the worst case trigger emergency restart
-	 */
-	WARN(1, "Attempting emergency_restart: Temperature too high\n");
-	emergency_restart();
-static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work,
-			    thermal_emergency_poweroff_func);
- * thermal_emergency_poweroff - Trigger an emergency system poweroff
- *
- * This may be called from any critical situation to trigger a system shutdown
- * after a known period of time. By default this is not scheduled.
- */
-static void thermal_emergency_poweroff(void)
+void thermal_zone_device_critical(struct thermal_zone_device *tz)
 	 * poweroff_delay_ms must be a carefully profiled positive value.
-	 * Its a must for thermal_emergency_poweroff_work to be scheduled
+	 * Its a must for forced_emergency_poweroff_work to be scheduled.
-	if (poweroff_delay_ms <= 0)
-		return;
-	schedule_delayed_work(&thermal_emergency_poweroff_work,
-			      msecs_to_jiffies(poweroff_delay_ms));
-void thermal_zone_device_critical(struct thermal_zone_device *tz)
 	dev_emerg(&tz->device, "%s: critical temperature reached, "
 		  "shutting down\n", tz->type);
-	mutex_lock(&poweroff_lock);
-	if (!power_off_triggered) {
-		/*
-		 * Queue a backup emergency shutdown in the event of
-		 * orderly_poweroff failure
-		 */
-		thermal_emergency_poweroff();
-		orderly_poweroff(true);
-		power_off_triggered = true;
-	}
-	mutex_unlock(&poweroff_lock);
+	hw_protection_shutdown("Temperature too high", poweroff_delay_ms);
@@ -1538,7 +1484,6 @@  static int __init thermal_init(void)
-	mutex_destroy(&poweroff_lock);
 	return result;