[PATCH RFC 1/4] thermal/core: Emit a warning if the thermal zone is updated without ops

[PATCH RFC 1/4] thermal/core: Emit a warning if the thermal zone is updated without ops

[Daniel Lezcano]

The actual code is silently ignoring a thermal zone update when a
driver is requesting it without a get_temp ops set.

That looks not correct, as the caller should not have called this
function if the thermal zone is unable to read the temperature.

That makes the code less robust as the check won't detect the driver
is inconsistently using the thermal API and that does not help to
improve the framework as these circumvolutions hide the problem at the
source.

In order to detect the situation when it happens, let's add a warning
when the update is requested without the get_temp() ops set.

Any warning emitted will have to be fixed at the source of the
problem: the caller must not call thermal_zone_device_update if there
is not get_temp callback set.

Cc: Thara Gopinath <thara.gopinath@linaro.org>
Cc: Amit Kucheria <amitk@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/thermal_core.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index dee40ff41177..afc02e7d1045 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -548,7 +548,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz,
 	if (atomic_read(&in_suspend))
 		return;
 
-	if (!tz->ops->get_temp)
+	if (WARN_ONCE(!tz->ops->get_temp, "'%s' must not be called without "
+		      "'get_temp' ops set\n", __FUNCTION__))
 		return;
 
 	update_temperature(tz);
-- 
2.17.1

[PATCH RFC 2/4] thermal/core: Add critical and hot ops

[Daniel Lezcano]

Currently there is no way to the sensors to directly call an ops in
interrupt mode without calling thermal_zone_device_update assuming all
the trip points are defined.

A sensor may want to do something special if a trip point is hot or
critical.

This patch adds the critical and hot ops to the thermal zone device,
so a sensor can directly invoke them or let the thermal framework to
call the sensor specific ones.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/thermal_core.c | 42 +++++++++++++++++++++-------------
 include/linux/thermal.h        |  3 +++
 2 files changed, 29 insertions(+), 16 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index afc02e7d1045..0366f3f076cc 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -375,6 +375,24 @@ static void thermal_emergency_poweroff(void)
 			      msecs_to_jiffies(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);
+}
+
 static void handle_critical_trips(struct thermal_zone_device *tz,
 				  int trip, enum thermal_trip_type trip_type)
 {
@@ -391,22 +409,10 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
 	if (tz->ops->notify)
 		tz->ops->notify(tz, trip, trip_type);
 
-	if (trip_type == THERMAL_TRIP_CRITICAL) {
-		dev_emerg(&tz->device,
-			  "critical temperature reached (%d C), shutting down\n",
-			  tz->temperature / 1000);
-		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);
-	}
+	if (trip_type == THERMAL_TRIP_HOT && tz->ops->hot)
+		tz->ops->hot(tz);
+	else if (trip_type == THERMAL_TRIP_CRITICAL)
+		tz->ops->critical(tz);
 }
 
 static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
@@ -1331,6 +1337,10 @@ thermal_zone_device_register(const char *type, int trips, int mask,
 
 	tz->id = id;
 	strlcpy(tz->type, type, sizeof(tz->type));
+
+	if (!ops->critical)
+		ops->critical = thermal_zone_device_critical;
+
 	tz->ops = ops;
 	tz->tzp = tzp;
 	tz->device.class = &thermal_class;
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index f23a388ded15..125c8a4d52e6 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -79,6 +79,8 @@ struct thermal_zone_device_ops {
 			  enum thermal_trend *);
 	int (*notify) (struct thermal_zone_device *, int,
 		       enum thermal_trip_type);
+	void (*hot)(struct thermal_zone_device *);
+	void (*critical)(struct thermal_zone_device *);
 };
 
 struct thermal_cooling_device_ops {
@@ -399,6 +401,7 @@ void thermal_cdev_update(struct thermal_cooling_device *);
 void thermal_notify_framework(struct thermal_zone_device *, int);
 int thermal_zone_device_enable(struct thermal_zone_device *tz);
 int thermal_zone_device_disable(struct thermal_zone_device *tz);
+void thermal_zone_device_critical(struct thermal_zone_device *tz);
 #else
 static inline struct thermal_zone_device *thermal_zone_device_register(
 	const char *type, int trips, int mask, void *devdata,
-- 
2.17.1

[PATCH RFC 3/4] thermal/drivers/acpi: Use hot and critical ops

[Daniel Lezcano]

The acpi driver wants to do a netlink notification in case of a hot or
critical trip point. Implement the corresponding ops to be used for
the thermal zone and use them instead of the notify ops.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/acpi/thermal.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/drivers/acpi/thermal.c b/drivers/acpi/thermal.c
index 12c0ece746f0..b5e4bc9e3282 100644
--- a/drivers/acpi/thermal.c
+++ b/drivers/acpi/thermal.c
@@ -677,27 +677,24 @@ static int thermal_get_trend(struct thermal_zone_device *thermal,
 	return 0;
 }
 
-
-static int thermal_notify(struct thermal_zone_device *thermal, int trip,
-			   enum thermal_trip_type trip_type)
+static void acpi_thermal_zone_device_hot(struct thermal_zone_device *thermal)
 {
-	u8 type = 0;
 	struct acpi_thermal *tz = thermal->devdata;
 
-	if (trip_type == THERMAL_TRIP_CRITICAL)
-		type = ACPI_THERMAL_NOTIFY_CRITICAL;
-	else if (trip_type == THERMAL_TRIP_HOT)
-		type = ACPI_THERMAL_NOTIFY_HOT;
-	else
-		return 0;
-
 	acpi_bus_generate_netlink_event(tz->device->pnp.device_class,
-					dev_name(&tz->device->dev), type, 1);
+					dev_name(&tz->device->dev),
+					ACPI_THERMAL_NOTIFY_HOT, 1);
+}
 
-	if (trip_type == THERMAL_TRIP_CRITICAL && nocrt)
-		return 1;
+static void acpi_thermal_zone_device_critical(struct thermal_zone_device *thermal)
+{
+	struct acpi_thermal *tz = thermal->devdata;
 
-	return 0;
+	acpi_bus_generate_netlink_event(tz->device->pnp.device_class,
+					dev_name(&tz->device->dev),
+					ACPI_THERMAL_NOTIFY_CRITICAL, 1);
+
+	thermal_zone_device_critical(thermal);
 }
 
 static int acpi_thermal_cooling_device_cb(struct thermal_zone_device *thermal,
@@ -812,7 +809,8 @@ static struct thermal_zone_device_ops acpi_thermal_zone_ops = {
 	.get_trip_temp = thermal_get_trip_temp,
 	.get_crit_temp = thermal_get_crit_temp,
 	.get_trend = thermal_get_trend,
-	.notify = thermal_notify,
+	.hot = acpi_thermal_zone_device_hot,
+	.critical = acpi_thermal_zone_device_critical,
 };
 
 static int acpi_thermal_register_thermal_zone(struct acpi_thermal *tz)
-- 
2.17.1

[PATCH RFC 4/4] thermal/core: Remove notify ops

[Daniel Lezcano]

With the remove of the notify user in a previous patch, the ops is no
longer needed, remove it.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/thermal_core.c | 3 ---
 include/linux/thermal.h        | 2 --
 2 files changed, 5 deletions(-)

diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
index 0366f3f076cc..8a47369f0432 100644
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -406,9 +406,6 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
 
 	trace_thermal_zone_trip(tz, trip, trip_type);
 
-	if (tz->ops->notify)
-		tz->ops->notify(tz, trip, trip_type);
-
 	if (trip_type == THERMAL_TRIP_HOT && tz->ops->hot)
 		tz->ops->hot(tz);
 	else if (trip_type == THERMAL_TRIP_CRITICAL)
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 125c8a4d52e6..7e051b4cf715 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -77,8 +77,6 @@ struct thermal_zone_device_ops {
 	int (*set_emul_temp) (struct thermal_zone_device *, int);
 	int (*get_trend) (struct thermal_zone_device *, int,
 			  enum thermal_trend *);
-	int (*notify) (struct thermal_zone_device *, int,
-		       enum thermal_trip_type);
 	void (*hot)(struct thermal_zone_device *);
 	void (*critical)(struct thermal_zone_device *);
 };
-- 
2.17.1

Re: [PATCH RFC 1/4] thermal/core: Emit a warning if the thermal zone is updated without ops

[Lukasz Luba]

Hi Daniel,

On 12/9/20 3:34 PM, Daniel Lezcano wrote:
> The actual code is silently ignoring a thermal zone update when a
> driver is requesting it without a get_temp ops set.
> 
> That looks not correct, as the caller should not have called this
> function if the thermal zone is unable to read the temperature.
> 
> That makes the code less robust as the check won't detect the driver
> is inconsistently using the thermal API and that does not help to
> improve the framework as these circumvolutions hide the problem at the
> source.
> 
> In order to detect the situation when it happens, let's add a warning
> when the update is requested without the get_temp() ops set.
> 
> Any warning emitted will have to be fixed at the source of the
> problem: the caller must not call thermal_zone_device_update if there
> is not get_temp callback set.
> 
> Cc: Thara Gopinath <thara.gopinath@linaro.org>
> Cc: Amit Kucheria <amitk@kernel.org>
> Cc: linux-pm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> ---
>   drivers/thermal/thermal_core.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index dee40ff41177..afc02e7d1045 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -548,7 +548,8 @@ void thermal_zone_device_update(struct thermal_zone_device *tz,
>   	if (atomic_read(&in_suspend))
>   		return;
>   
> -	if (!tz->ops->get_temp)
> +	if (WARN_ONCE(!tz->ops->get_temp, "'%s' must not be called without "
> +		      "'get_temp' ops set\n", __FUNCTION__))
>   		return;
>   
>   	update_temperature(tz);
> 

With this RFC and the link that you gave me in previous thread, I see
the motivation.

I would change __FUNCTION__ into __func__, but other than that LGTM.

Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>

Regards,
Lukasz

Re: [PATCH RFC 2/4] thermal/core: Add critical and hot ops

[Kai-Heng Feng]

> On Dec 9, 2020, at 23:34, Daniel Lezcano <daniel.lezcano@linaro.org> wrote:
> 
> Currently there is no way to the sensors to directly call an ops in
> interrupt mode without calling thermal_zone_device_update assuming all
> the trip points are defined.
> 
> A sensor may want to do something special if a trip point is hot or
> critical.
> 
> This patch adds the critical and hot ops to the thermal zone device,
> so a sensor can directly invoke them or let the thermal framework to
> call the sensor specific ones.
> 
> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Thanks. This can solve my issue once .critical callbacks are added in thermal drivers.

Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

> ---
> drivers/thermal/thermal_core.c | 42 +++++++++++++++++++++-------------
> include/linux/thermal.h        |  3 +++
> 2 files changed, 29 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index afc02e7d1045..0366f3f076cc 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -375,6 +375,24 @@ static void thermal_emergency_poweroff(void)
> 			      msecs_to_jiffies(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);
> +}
> +
> static void handle_critical_trips(struct thermal_zone_device *tz,
> 				  int trip, enum thermal_trip_type trip_type)
> {
> @@ -391,22 +409,10 @@ static void handle_critical_trips(struct thermal_zone_device *tz,
> 	if (tz->ops->notify)
> 		tz->ops->notify(tz, trip, trip_type);
> 
> -	if (trip_type == THERMAL_TRIP_CRITICAL) {
> -		dev_emerg(&tz->device,
> -			  "critical temperature reached (%d C), shutting down\n",
> -			  tz->temperature / 1000);
> -		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);
> -	}
> +	if (trip_type == THERMAL_TRIP_HOT && tz->ops->hot)
> +		tz->ops->hot(tz);
> +	else if (trip_type == THERMAL_TRIP_CRITICAL)
> +		tz->ops->critical(tz);
> }
> 
> static void handle_thermal_trip(struct thermal_zone_device *tz, int trip)
> @@ -1331,6 +1337,10 @@ thermal_zone_device_register(const char *type, int trips, int mask,
> 
> 	tz->id = id;
> 	strlcpy(tz->type, type, sizeof(tz->type));
> +
> +	if (!ops->critical)
> +		ops->critical = thermal_zone_device_critical;
> +
> 	tz->ops = ops;
> 	tz->tzp = tzp;
> 	tz->device.class = &thermal_class;
> diff --git a/include/linux/thermal.h b/include/linux/thermal.h
> index f23a388ded15..125c8a4d52e6 100644
> --- a/include/linux/thermal.h
> +++ b/include/linux/thermal.h
> @@ -79,6 +79,8 @@ struct thermal_zone_device_ops {
> 			  enum thermal_trend *);
> 	int (*notify) (struct thermal_zone_device *, int,
> 		       enum thermal_trip_type);
> +	void (*hot)(struct thermal_zone_device *);
> +	void (*critical)(struct thermal_zone_device *);
> };
> 
> struct thermal_cooling_device_ops {
> @@ -399,6 +401,7 @@ void thermal_cdev_update(struct thermal_cooling_device *);
> void thermal_notify_framework(struct thermal_zone_device *, int);
> int thermal_zone_device_enable(struct thermal_zone_device *tz);
> int thermal_zone_device_disable(struct thermal_zone_device *tz);
> +void thermal_zone_device_critical(struct thermal_zone_device *tz);
> #else
> static inline struct thermal_zone_device *thermal_zone_device_register(
> 	const char *type, int trips, int mask, void *devdata,
> -- 
> 2.17.1
>