[PATCH v9 2/3] reboot: Introduce thermal_zone_device_critical_reboot()

[Fabio Estevam <festevam@gmail.com>]

From: Fabio Estevam <festevam@denx.de>

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>
---
Changes since v8:
- Introduce thermal_zone_device_critical_reboot() to accomodate
Daniel's suggestions.

 drivers/thermal/thermal_core.c | 19 +++++++++++++++++--
 include/linux/reboot.h         | 13 ++++++++++++-
 include/linux/thermal.h        |  1 +
 kernel/reboot.c                | 32 +++++++++++++++++++-------------
 4 files changed, 49 insertions(+), 16 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 38d393f139d8..277aafb294db 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -313,21 +313,36 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip)
 		       def_governor->throttle(tz, trip);
 }
 
-void thermal_zone_device_critical(struct thermal_zone_device *tz)
+static void thermal_zone_device_shutdown(struct thermal_zone_device *tz, bool shutdown)
 {
 	/*
 	 * poweroff_delay_ms must be a carefully profiled positive value.
 	 * Its a must for forced_emergency_poweroff_work to be scheduled.
 	 */
 	int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS;
+	static const char *msg = "Temperature too high";
 
 	dev_emerg(&tz->device, "%s: critical temperature reached, "
 		  "shutting down\n", tz->type);
 
-	hw_protection_shutdown("Temperature too high", poweroff_delay_ms);
+	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)
+{
+	thermal_zone_device_shutdown(tz, true);
 }
 EXPORT_SYMBOL(thermal_zone_device_critical);
 
+void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz)
+{
+	thermal_zone_device_shutdown(tz, false);
+}
+EXPORT_SYMBOL(thermal_zone_device_critical_reboot);
+
 static void handle_critical_trips(struct thermal_zone_device *tz,
 				  int trip, int trip_temp, enum thermal_trip_type trip_type)
 {
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index c4cc3b89ced1..4683e117c753 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -177,7 +177,18 @@ void ctrl_alt_del(void);
 
 extern void orderly_poweroff(bool force);
 extern void orderly_reboot(void);
-void hw_protection_shutdown(const char *reason, int ms_until_forced);
+
+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);
+}
 
 /*
  * Emergency restart, callable from an interrupt handler.
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 6cfcae22ba12..c5ebb44ae8a6 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -353,6 +353,7 @@ int thermal_zone_get_offset(struct thermal_zone_device *tz);
 int thermal_zone_device_enable(struct thermal_zone_device *tz);
 int thermal_zone_device_disable(struct thermal_zone_device *tz);
 void thermal_zone_device_critical(struct thermal_zone_device *tz);
+void thermal_zone_device_critical_reboot(struct thermal_zone_device *tz);
 #else
 static inline struct thermal_zone_device *thermal_zone_device_register_with_trips(
 					const char *type,
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 395a0ea3c7a8..8b3010b88ed6 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -957,21 +957,25 @@ 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.
+ * 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.
  * Can be called from any context.
  */
-void hw_protection_shutdown(const char *reason, int ms_until_forced)
+void __hw_protection_shutdown(const char *reason, int ms_until_forced, bool shutdown)
 {
 	static atomic_t allow_proceed = ATOMIC_INIT(1);
 
@@ -986,9 +990,11 @@ void hw_protection_shutdown(const char *reason, int ms_until_forced)
 	 * orderly_poweroff failure
 	 */
 	hw_failure_emergency_poweroff(ms_until_forced);
-	orderly_poweroff(true);
+	if (shutdown)
+		orderly_poweroff(true);
+	else
+		orderly_reboot();
 }
-EXPORT_SYMBOL_GPL(hw_protection_shutdown);
 
 static int __init reboot_setup(char *str)
 {
-- 
2.34.1