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thermal: Use generic HW-protection shutdown API

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The hardware shutdown function was exported from kernel/reboot for
other subsystems to use. Logic is copied from the thermal_core. The
protection mutex is replaced by an atomic_t to allow calls also from
an IRQ context. Also the WARN() was replaced by pr_emerg() based on
discussions here:
https://lore.kernel.org/lkml/YJuPwAZroVZ%2Fw633@alley/
and here:
https://lore.kernel.org/linux-iommu/20210331093104.383705-4-geert+renesas@glider.be/

Use the exported API instead of implementing own just for the
thermal_core.

Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/5531e89d9e710f5d10e7cdce3ee58957335b9e03.1622628333.git.matti.vaittinen@fi.rohmeurope.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Matti Vaittinen 2021-06-03 08:41:03 +03:00 committed by Mark Brown
parent dfa19b1138
commit db0aeb4f07
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GPG Key ID: 24D68B725D5487D0
2 changed files with 16 additions and 77 deletions
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24
Documentation/driver-api/thermal/sysfs-api.rst
View File

@ -740,21 +740,15 @@ possible.
5. thermal_emergency_poweroff
=============================
On an event of critical trip temperature crossing. Thermal framework
allows the system to shutdown gracefully by calling orderly_poweroff().
In the event of a failure of orderly_poweroff() to shut down the system
we are in danger of keeping the system alive at undesirably high
temperatures. To mitigate this high risk scenario we program a work
queue to fire after a pre-determined number of seconds to start
an emergency shutdown of the device using the kernel_power_off()
function. In case kernel_power_off() fails then finally
emergency_restart() is called in the worst case.
On an event of critical trip temperature crossing the thermal framework
shuts down the system by calling hw_protection_shutdown(). The
hw_protection_shutdown() first attempts to perform an orderly shutdown
but accepts a delay after which it proceeds doing a forced power-off
or as last resort an emergency_restart.
The delay should be carefully profiled so as to give adequate time for
orderly_poweroff(). In case of failure of an orderly_poweroff() the
emergency poweroff kicks in after the delay has elapsed and shuts down
the system.
orderly poweroff.
If set to 0 emergency poweroff will not be supported. So a carefully
profiled non-zero positive value is a must for emergency poweroff to be
triggered.
If the delay is set to 0 emergency poweroff will not be supported. So a
carefully profiled non-zero positive value is a must for emergency
poweroff to be triggered.

69
drivers/thermal/thermal_core.c
View File

@ -36,10 +36,8 @@ static LIST_HEAD(thermal_governor_list);
static DEFINE_MUTEX(thermal_list_lock);
static DEFINE_MUTEX(thermal_governor_lock);
static DEFINE_MUTEX(poweroff_lock);
static atomic_t in_suspend;
static bool power_off_triggered;
static struct thermal_governor *def_governor;
@ -327,70 +325,18 @@ static void handle_non_critical_trips(struct thermal_zone_device *tz, int trip)
def_governor->throttle(tz, trip);
}
/**
* thermal_emergency_poweroff_func - emergency poweroff work after a known delay
* @work: work_struct associated with the emergency poweroff function
*
* This function is called in very critical situations to force
* a kernel poweroff after a configurable timeout value.
*/
static void thermal_emergency_poweroff_func(struct work_struct *work)
{
/*
* We have reached here after the emergency thermal shutdown
* Waiting period has expired. This means orderly_poweroff has
* not been able to shut off the system for some reason.
* Try to shut down the system immediately using kernel_power_off
* if populated
*/
WARN(1, "Attempting kernel_power_off: Temperature too high\n");
kernel_power_off();
/*
* Worst of the worst case trigger emergency restart
*/
WARN(1, "Attempting emergency_restart: Temperature too high\n");
emergency_restart();
}
static DECLARE_DELAYED_WORK(thermal_emergency_poweroff_work,
thermal_emergency_poweroff_func);
/**
* thermal_emergency_poweroff - Trigger an emergency system poweroff
*
* This may be called from any critical situation to trigger a system shutdown
* after a known period of time. By default this is not scheduled.
*/
static void thermal_emergency_poweroff(void)
{
int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS;
/*
* poweroff_delay_ms must be a carefully profiled positive value.
* Its a must for thermal_emergency_poweroff_work to be scheduled
*/
if (poweroff_delay_ms <= 0)
return;
schedule_delayed_work(&thermal_emergency_poweroff_work,
msecs_to_jiffies(poweroff_delay_ms));
}
void thermal_zone_device_critical(struct thermal_zone_device *tz)
{
/*
* 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;
dev_emerg(&tz->device, "%s: critical temperature reached, "
"shutting down\n", tz->type);
mutex_lock(&poweroff_lock);
if (!power_off_triggered) {
/*
* Queue a backup emergency shutdown in the event of
* orderly_poweroff failure
*/
thermal_emergency_poweroff();
orderly_poweroff(true);
power_off_triggered = true;
}
mutex_unlock(&poweroff_lock);
hw_protection_shutdown("Temperature too high", poweroff_delay_ms);
}
EXPORT_SYMBOL(thermal_zone_device_critical);
@ -1538,7 +1484,6 @@ error:
ida_destroy(&thermal_cdev_ida);
mutex_destroy(&thermal_list_lock);
mutex_destroy(&thermal_governor_lock);
mutex_destroy(&poweroff_lock);
return result;
}
postcore_initcall(thermal_init);