dt-bindings: thermal-zones: Document critical-action
Subsystems (2)
PATCH v3 1/3 dt-bindings: thermal-zones: Document critical-action
From: Fabio Estevam <[email protected]>
Document the critical-action property to describe the thermal action the OS should perform after the critical temperature is reached.
The possible values are "shutdown" and "reboot".
---
Changes since v2:
- Improve the description. (Krzysztof)
- Don't repeat constraints in free form text. (Krzysztof)
- Remove the enum comments. (Krzysztof)
.../devicetree/bindings/thermal/thermal-zones.yaml | 9 +++++++++ 1 file changed, 9 insertions(+)
Documentation/devicetree/bindings/thermal/thermal-zones.yaml +9 -0
@@ -75,6 +75,15 @@ patternProperties: framework and assumes that the thermal sensors in this zone support interrupts. + critical-action: + $ref: /schemas/types.yaml#/definitions/string + description: + The action the OS should perform after the critical temperature is reached. + + enum: + - shutdown + - reboot + thermal-sensors: $ref: /schemas/types.yaml#/definitions/phandle-array maxItems: 1
Signature · 1 line
2.34.1
PATCH v3 2/3 reboot: Introduce hw_protection_reboot()
From: Fabio Estevam <[email protected]>
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.
---
Changes since v2:
- None
include/linux/reboot.h | 1 + kernel/reboot.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+)
include/linux/reboot.h +1 -0
@@ -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);/*
kernel/reboot.c +34 -0
@@ -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 *
Signature · 1 line
2.34.1
PATCH v3 3/3 thermal: thermal_core: Allow rebooting after critical temp
In reply to Fabio EstevamFrom: Fabio Estevam <[email protected]>
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";
};
};---
Changes since v2:
- None.
drivers/thermal/thermal_core.c | 8 +++++++- drivers/thermal/thermal_of.c | 27 +++++++++++++++++++++++++++ include/linux/thermal.h | 6 ++++++ 3 files changed, 40 insertions(+), 1 deletion(-)
drivers/thermal/thermal_core.c +7 -1
@@ -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);
drivers/thermal/thermal_of.c +27 -0
@@ -218,6 +218,31 @@ static struct device_node *of_thermal_zone_find(struct device_node *sensor, intreturn 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",
include/linux/thermal.h +6 -0
@@ -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; };/**
Signature · 1 line
2.34.1
Quoted 4 lines · Fabio Estevam
From: Fabio Estevam <[email protected]>
Document the critical-action property to describe the thermal action the OS should perform after the critical temperature is reached.
We see that from the diff. You should explain here why you need it, why this is good idea. You should provide here answers to my concerns on v1, so you do not get exactly the same question from Conor or Rob or anyone else.
Best regards,
Krzysztof