Re: [PATCH v8 03/10] thermal: Use generic HW-protection shutdown API

From: Daniel Lezcano
Date: Thu Apr 22 2021 - 04:10:49 EST


On 19/04/2021 13:49, Matti Vaittinen wrote:
> 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.
>
> Use the exported API instead of implementing own just for the
> thermal_core.

Can you update the documentation:

Documentation/driver-api/thermal/sysfs-api.rst

5. thermal_emergency_poweroff

Thanks
-- Daniel


> Signed-off-by: Matti Vaittinen <matti.vaittinen@xxxxxxxxxxxxxxxxx>
>
> ---
> Changelog:
> v8:
> - new patch (change added in v7, splitted in own patch at v8)
>
> Use the exported API instead
> ---
> drivers/thermal/thermal_core.c | 63 +++-------------------------------
> 1 file changed, 4 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 996c038f83a4..b1444845af38 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -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)
> +void thermal_zone_device_critical(struct thermal_zone_device *tz)
> {
> - 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
> + * Its a must for forced_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));
> -}
> + int poweroff_delay_ms = CONFIG_THERMAL_EMERGENCY_POWEROFF_DELAY_MS;
>
> -void thermal_zone_device_critical(struct thermal_zone_device *tz)
> -{
> 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);
>
> @@ -1549,7 +1495,6 @@ static int __init thermal_init(void)
> 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);
>


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