* [PATCH 3/4] reboot: Introduce hw_protection_reboot()
2023-08-25 10:24 [PATCH 1/4] dt-bindings: thermal-zones: Document critical-action Fabio Estevam
2023-08-25 10:24 ` [PATCH 2/4] dt-bindings: thermal: Document the values for the 'critical-action' Fabio Estevam
@ 2023-08-25 10:24 ` Fabio Estevam
2023-08-25 10:24 ` [PATCH 4/4] thermal: thermal_core: Allow rebooting after critical temp Fabio Estevam
2 siblings, 0 replies; 4+ messages in thread
From: Fabio Estevam @ 2023-08-25 10:24 UTC (permalink / raw)
To: daniel.lezcano
Cc: rafael, amitk, rui.zhang, linux-pm, krzysztof.kozlowski+dt,
robh+dt, conor+dt, devicetree, Fabio Estevam
From: Fabio Estevam <festevam@denx.de>
Introduce hw_protection_reboot() to trigger an emergency reboot.
It is a counterpart of hw_protection_shutdown() 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>
---
include/linux/reboot.h | 1 +
kernel/reboot.c | 34 ++++++++++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/include/linux/reboot.h b/include/linux/reboot.h
index 2b6bb593be5b..4a319bc24f6a 100644
--- a/include/linux/reboot.h
+++ b/include/linux/reboot.h
@@ -174,6 +174,7 @@ void ctrl_alt_del(void);
extern void orderly_poweroff(bool force);
extern void orderly_reboot(void);
+void hw_protection_reboot(const char *reason, int ms_until_forced);
void hw_protection_shutdown(const char *reason, int ms_until_forced);
/*
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3bba88c7ffc6..64517d1e4c55 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -952,6 +952,40 @@ static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
msecs_to_jiffies(poweroff_delay_ms));
}
+/**
+ * hw_protection_reboot - Trigger an emergency system reboot
+ *
+ * @reason: Reason of emergency reboot to be printed.
+ * @ms_until_forced: Time to wait for orderly reboot before tiggering a
+ * forced reboot. Negative value disables the forced
+ * reboot.
+ *
+ * Initiate an emergency system reboot in order to protect hardware from
+ * further damage. Usage examples include a thermal protection.
+ *
+ * NOTE: The request is ignored if protection reboot is already pending even
+ * if the previous request has given a large timeout for forced reboot.
+ * Can be called from any context.
+ */
+void hw_protection_reboot(const char *reason, int ms_until_forced)
+{
+ static atomic_t allow_proceed = ATOMIC_INIT(1);
+
+ pr_emerg("HARDWARE PROTECTION reboot (%s)\n", reason);
+
+ /* Reboot should be initiated only once. */
+ if (!atomic_dec_and_test(&allow_proceed))
+ return;
+
+ /*
+ * Queue a backup emergency reboot in the event of
+ * orderly_reboot failure
+ */
+ hw_failure_emergency_poweroff(ms_until_forced);
+ orderly_reboot();
+}
+EXPORT_SYMBOL_GPL(hw_protection_reboot);
+
/**
* hw_protection_shutdown - Trigger an emergency system poweroff
*
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 4/4] thermal: thermal_core: Allow rebooting after critical temp
2023-08-25 10:24 [PATCH 1/4] dt-bindings: thermal-zones: Document critical-action Fabio Estevam
2023-08-25 10:24 ` [PATCH 2/4] dt-bindings: thermal: Document the values for the 'critical-action' Fabio Estevam
2023-08-25 10:24 ` [PATCH 3/4] reboot: Introduce hw_protection_reboot() Fabio Estevam
@ 2023-08-25 10:24 ` Fabio Estevam
2 siblings, 0 replies; 4+ messages in thread
From: Fabio Estevam @ 2023-08-25 10:24 UTC (permalink / raw)
To: daniel.lezcano
Cc: rafael, amitk, rui.zhang, linux-pm, krzysztof.kozlowski+dt,
robh+dt, conor+dt, devicetree, Fabio Estevam
From: Fabio Estevam <festevam@denx.de>
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 devicetre changes:
thermal-zones {
cpu-thermal {
critical-action = <THERMAL_CRITICAL_ACTION_REBOOT>;
};
};
Signed-off-by: Fabio Estevam <festevam@denx.de>
---
drivers/thermal/thermal_core.c | 8 +++++++-
drivers/thermal/thermal_of.c | 17 ++++++++++++++---
include/linux/thermal.h | 6 ++++++
3 files changed, 27 insertions(+), 4 deletions(-)
diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index cc2b5e81c620..3f4ea27560f8 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 330690a3a208..36a2c82d3405 100644
--- a/drivers/thermal/thermal_of.c
+++ b/drivers/thermal/thermal_of.c
@@ -218,7 +218,8 @@ static struct device_node *of_thermal_zone_find(struct device_node *sensor, int
return tz;
}
-static int thermal_of_monitor_init(struct device_node *np, int *delay, int *pdelay)
+static int thermal_of_monitor_init(struct device_node *np, int *delay,
+ int *pdelay, int *critical_action)
{
int ret;
@@ -234,6 +235,14 @@ static int thermal_of_monitor_init(struct device_node *np, int *delay, int *pdel
return ret;
}
+ /*
+ * If the "critical-action" property is not found, fall back to
+ * the shutdown action to keep the existing behavior.
+ */
+ ret = of_property_read_u32(np, "critical-action", critical_action);
+ if (ret < 0)
+ *critical_action = THERMAL_CRITICAL_ACTION_SHUTDOWN;
+
return 0;
}
@@ -471,7 +480,7 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
struct thermal_zone_params tzp = {};
struct thermal_zone_device_ops *of_ops;
struct device_node *np;
- int delay, pdelay;
+ int delay, pdelay, critical_action;
int ntrips, mask;
int ret;
@@ -494,7 +503,7 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
goto out_kfree_of_ops;
}
- ret = thermal_of_monitor_init(np, &delay, &pdelay);
+ ret = thermal_of_monitor_init(np, &delay, &pdelay, &critical_action);
if (ret) {
pr_err("Failed to initialize monitoring delays from %pOFn\n", np);
goto out_kfree_trips;
@@ -516,6 +525,8 @@ static struct thermal_zone_device *thermal_of_zone_register(struct device_node *
goto out_kfree_trips;
}
+ tz->action = critical_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 dee66ade89a0..48f29ab16218 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 */
@@ -185,6 +190,7 @@ 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
^ permalink raw reply related [flat|nested] 4+ messages in thread