From: Fabio Estevam <festevam@xxxxxxx>
Currently, the default mechanism is to trigger a shutdown after the
critical temperature is reached.
In some embedded cases, such behavior does not suit well, as the board may
be unattended in the field and rebooting may be a better approach.
The bootloader may also check the temperature and only allow the boot to
proceed when the temperature is below a certain threshold.
Introduce support for allowing a reboot to be triggered after the
critical temperature is reached.
If the "critical-action" devicetree property is not found, fall back to
the shutdown action to preserve the existing default behavior.
Tested on a i.MX8MM board with the following devicetree changes:
thermal-zones {
cpu-thermal {
critical-action = "reboot";
};
};
Signed-off-by: Fabio Estevam <festevam@xxxxxxx>
---
Changes since v1:
- Adapt to handle 'critical-changes' property as string.
drivers/thermal/thermal_core.c | 8 +++++++-
drivers/thermal/thermal_of.c | 27 +++++++++++++++++++++++++++
include/linux/thermal.h | 6 ++++++
3 files changed, 40 insertions(+), 1 deletion(-)
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index a59700593d32..f69e1667acb1 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -320,11 +320,17 @@ void thermal_zone_device_critical(struct thermal_zone_device *tz)
* Its a must for forced_emergency_poweroff_work to be scheduled.
*/
int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS;
+ void (*hw_protection_action)(const char *reason, int ms_until_forced);
dev_emerg(&tz->device, "%s: critical temperature reached, "
"shutting down\n", tz->type);
- hw_protection_shutdown("Temperature too high", poweroff_delay_ms);
+ hw_protection_action = hw_protection_shutdown;
+
+ if (tz->action == THERMAL_CRITICAL_ACTION_REBOOT)
+ hw_protection_action = hw_protection_reboot;
+
+ hw_protection_action("Temperature too high", poweroff_delay_ms);
}
EXPORT_SYMBOL(thermal_zone_device_critical);
diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
index 4ca905723429..8bc28cba7406 100644
--- a/drivers/thermal/thermal_of.c
+++ b/drivers/thermal/thermal_of.c
@@ -218,6 +218,31 @@ static struct device_node *of_thermal_zone_find(struct device_node *sensor, int
return tz;
}
+static const char * const critical_actions[] = {
+ [THERMAL_CRITICAL_ACTION_SHUTDOWN] = "shutdown",
+ [THERMAL_CRITICAL_ACTION_REBOOT] = "reboot",
+};
+
+static void thermal_of_get_critical_action(struct device_node *np,
+ enum thermal_action *action)
+{
+ const char *action_string;
+ int i, ret;
+
+ ret = of_property_read_string(np, "critical-action", &action_string);
+ if (ret < 0)
+ goto out_default_action;
+
+ for (i = 0; i < ARRAY_SIZE(critical_actions); i++)
+ if (!strcasecmp(action_string, critical_actions[i])) {
+ *action = i;
+ return;
+ }
+
+out_default_action:
+ *action = THERMAL_CRITICAL_ACTION_SHUTDOWN;
+}
+
static int thermal_of_monitor_init(struct device_node *np, int *delay, int *pdelay)
{
int ret;
@@ -516,6 +541,8 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
goto out_kfree_trips;
}
+ thermal_of_get_critical_action(np, &tz->action);
+
ret = thermal_zone_device_enable(tz);
if (ret) {
pr_err("Failed to enabled thermal zone '%s', id=%d: %d\n",
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index b449a46766f5..08854f640db9 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -34,6 +34,11 @@ struct thermal_cooling_device;
struct thermal_instance;
struct thermal_attr;
+enum thermal_action {
+ THERMAL_CRITICAL_ACTION_SHUTDOWN, /* shutdown when crit temperature is reached */
+ THERMAL_CRITICAL_ACTION_REBOOT, /* reboot when crit temperature is reached */
+};
+
enum thermal_trend {
THERMAL_TREND_STABLE, /* temperature is stable */
THERMAL_TREND_RAISING, /* temperature is raising */
@@ -187,6 +192,7 @@ struct thermal_zone_device {
struct list_head node;
struct delayed_work poll_queue;
enum thermal_notify_event notify_event;
+ enum thermal_action action;
};
/**
--
2.34.1
