reboot: Introduce thermal_zone_device_critical_reboot()

Introduce thermal_zone_device_critical_reboot() to trigger an
emergency reboot.

It is a counterpart of thermal_zone_device_critical() with the
difference that it will force a reboot instead of shutdown.

The motivation for doing this is to allow the thermal subystem
to trigger a reboot when the temperature reaches the critical
temperature.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20231129124330.519423-3-festevam@gmail.com

Author: Fabio Estevam

drivers/thermal/thermal_core.c

@@ -324,6 +324,8 @@ static void thermal_zone_device_halt(struct thermal_zone_device *tz, bool shutdo
 
 	if (shutdown)
 		hw_protection_shutdown(msg, poweroff_delay_ms);
+	else
+		hw_protection_reboot(msg, poweroff_delay_ms);
 }
 
 void thermal_zone_device_critical(struct thermal_zone_device *tz)
@@ -332,6 +334,11 @@ void thermal_zone_device_critical(struct thermal_zone_device *tz)
 }
 EXPORT_SYMBOL(thermal_zone_device_critical);
 
+void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz)
+{
+	thermal_zone_device_halt(tz, false);
+}
+
 static void handle_critical_trips(struct thermal_zone_device *tz,
 				  const struct thermal_trip *trip)
 {

drivers/thermal/thermal_core.h

@@ -114,6 +114,7 @@ int thermal_zone_device_set_policy(struct thermal_zone_device *, char *);
 int thermal_build_list_of_policies(char *buf);
 void __thermal_zone_device_update(struct thermal_zone_device *tz,
 				  enum thermal_notify_event event);
+void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz);
 
 /* Helpers */
 #define for_each_trip(__tz, __trip)	\

include/linux/reboot.h

@@ -179,6 +179,11 @@ extern void orderly_poweroff(bool force);
 extern void orderly_reboot(void);
 void __hw_protection_shutdown(const char *reason, int ms_until_forced, bool shutdown);
 
+static inline void hw_protection_reboot(const char *reason, int ms_until_forced)
+{
+	__hw_protection_shutdown(reason, ms_until_forced, false);
+}
+
 static inline void hw_protection_shutdown(const char *reason, int ms_until_forced)
 {
 	__hw_protection_shutdown(reason, ms_until_forced, true);

kernel/reboot.c

@@ -957,19 +957,22 @@ static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
 }
 
 /**
- * __hw_protection_shutdown - Trigger an emergency system poweroff
+ * __hw_protection_shutdown - Trigger an emergency system shutdown or reboot
  *
- * @reason:		Reason of emergency shutdown to be printed.
- * @ms_until_forced:	Time to wait for orderly shutdown before tiggering a
- *			forced shudown. Negative value disables the forced
- *			shutdown.
+ * @reason:		Reason of emergency shutdown or reboot to be printed.
+ * @ms_until_forced:	Time to wait for orderly shutdown or reboot before
+ *			triggering it. Negative value disables the forced
+ *			shutdown or reboot.
+ * @shutdown:		If true, indicates that a shutdown will happen
+ *			after the critical tempeature is reached.
+ *			If false, indicates that a reboot will happen
+ *			after the critical tempeature is reached.
  *
- * Initiate an emergency system shutdown in order to protect hardware from
- * further damage. Usage examples include a thermal protection or a voltage or
- * current regulator failures.
- * NOTE: The request is ignored if protection shutdown is already pending even
- * if the previous request has given a large timeout for forced shutdown.
- * Can be called from any context.
+ * Initiate an emergency system shutdown or reboot in order to protect
+ * hardware from further damage. Usage examples include a thermal protection.
+ * NOTE: The request is ignored if protection shutdown or reboot is already
+ * pending even if the previous request has given a large timeout for forced
+ * shutdown/reboot.
  */
 void __hw_protection_shutdown(const char *reason, int ms_until_forced, bool shutdown)
 {
@@ -988,7 +991,10 @@ void __hw_protection_shutdown(const char *reason, int ms_until_forced, bool shut
 	hw_failure_emergency_poweroff(ms_until_forced);
 	if (shutdown)
 		orderly_poweroff(true);
+	else
+		orderly_reboot();
 }
+EXPORT_SYMBOL_GPL(__hw_protection_shutdown);
 
 static int __init reboot_setup(char *str)
 {