1 // SPDX-License-Identifier: GPL-2.0
3  * A power allocator to manage temperature
9 #define pr_fmt(fmt) "Power allocator: " fmt
20 #define INVALID_TRIP -1
27  * mul_frac() - multiply two fixed-point numbers
31  * Return: the result of multiplying two fixed-point numbers.  The
32  * result is also a fixed-point number.
40  * div_frac() - divide two fixed-point numbers
44  * Return: the result of dividing two fixed-point numbers.  The
45  * result is also a fixed-point number.
53  * struct power_allocator_params - parameters for the power allocator governor
66  * @sustainable_power:	Sustainable power (heat) that this thermal zone can
79  * estimate_sustainable_power() - Estimate the sustainable power of a thermal zone
84  * power of all the cooling devices as that gives a valid value that
93 	struct power_allocator_params *params = tz->governor_data;  in estimate_sustainable_power()
95 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in estimate_sustainable_power()
96 		struct thermal_cooling_device *cdev = instance->cdev;  in estimate_sustainable_power()
99 		if (instance->trip != params->trip_max_desired_temperature)  in estimate_sustainable_power()
105 		if (cdev->ops->state2power(cdev, instance->upper, &min_power))  in estimate_sustainable_power()
115  * estimate_pid_constants() - Estimate the constants for the PID controller
117  * @sustainable_power:	sustainable power for the thermal zone
119  * @control_temp:	target temperature for the power allocator governor
133 	ret = tz->ops->get_trip_temp(tz, trip_switch_on, &switch_on_temp);  in estimate_pid_constants()
137 	temperature_threshold = control_temp - switch_on_temp;  in estimate_pid_constants()
149 	tz->tzp->k_po = int_to_frac(sustainable_power) /  in estimate_pid_constants()
152 	tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /  in estimate_pid_constants()
155 	k_i = tz->tzp->k_pu / 10;  in estimate_pid_constants()
156 	tz->tzp->k_i = k_i > 0 ? k_i : 1;  in estimate_pid_constants()
165  * get_sustainable_power() - Get the right sustainable power
167  * @params:	parameters for the power allocator governor
168  * @control_temp:	target temperature for the power allocator governor
170  * This function is used for getting the proper sustainable power value based
181 	if (!tz->tzp->sustainable_power)  in get_sustainable_power()
184 		sustainable_power = tz->tzp->sustainable_power;  in get_sustainable_power()
187 	if (sustainable_power != params->sustainable_power) {  in get_sustainable_power()
189 				       params->trip_switch_on, control_temp);  in get_sustainable_power()
192 		tz->tzp->sustainable_power = sustainable_power;  in get_sustainable_power()
193 		params->sustainable_power = sustainable_power;  in get_sustainable_power()
200  * pid_controller() - PID controller
203  * @max_allocatable_power:	maximum allocatable power for this thermal zone
205  * This PID controller increases the available power budget so that the
207  * @control_temp and limits the power if it exceeds it.  k_po is the
211  * accumulated error is only valid if the requested power will make
215  * Return: The power budget for the next period.
224 	struct power_allocator_params *params = tz->governor_data;  in pid_controller()
230 	err = control_temp - tz->temperature;  in pid_controller()
234 	p = mul_frac(err < 0 ? tz->tzp->k_po : tz->tzp->k_pu, err);  in pid_controller()
240 	 * the integral is limited to max power)  in pid_controller()
242 	i = mul_frac(tz->tzp->k_i, params->err_integral);  in pid_controller()
244 	if (err < int_to_frac(tz->tzp->integral_cutoff)) {  in pid_controller()
245 		s64 i_next = i + mul_frac(tz->tzp->k_i, err);  in pid_controller()
249 			params->err_integral += err;  in pid_controller()
256 	 * We do err - prev_err, so with a positive k_d, a decreasing  in pid_controller()
258 	 * power being applied, slowing down the controller)  in pid_controller()
260 	d = mul_frac(tz->tzp->k_d, err - params->prev_err);  in pid_controller()
261 	d = div_frac(d, jiffies_to_msecs(tz->passive_delay_jiffies));  in pid_controller()
262 	params->prev_err = err;  in pid_controller()
266 	/* feed-forward the known sustainable dissipatable power */  in pid_controller()
272 					  frac_to_int(params->err_integral),  in pid_controller()
280  * power_actor_set_power() - limit the maximum power a cooling device consumes
283  * @power:	the power in milliwatts
285  * Set the cooling device to consume at most @power milliwatts. The limit is
286  * expected to be a cap at the maximum power consumption.
288  * Return: 0 on success, -EINVAL if the cooling device does not
289  * implement the power actor API or -E* for other failures.
293 		      struct thermal_instance *instance, u32 power)  in power_actor_set_power()  argument
298 	ret = cdev->ops->power2state(cdev, power, &state);  in power_actor_set_power()
302 	instance->target = clamp_val(state, instance->lower, instance->upper);  in power_actor_set_power()
303 	mutex_lock(&cdev->lock);  in power_actor_set_power()
305 	mutex_unlock(&cdev->lock);  in power_actor_set_power()
311  * divvy_up_power() - divvy the allocated power between the actors
312  * @req_power:	each actor's requested power
313  * @max_power:	each actor's maximum available power
316  * @power_range:	total allocated power
317  * @granted_power:	output array: each actor's granted power
319  *			function as temporary storage of the extra power given
322  * This function divides the total allocated power (@power_range)
324  * share of the @power_range according to how much power it requested
326  * requests power, then it receives all the @power_range.  If
330  * If any actor received more than their maximum power, then that
331  * surplus is re-divvied among the actors based on how far they are
334  * Granted power for each actor is written to @granted_power, which
345 	 * Prevent division by 0 if none of the actors request power.  in divvy_up_power()
359 			extra_power += granted_power[i] - max_power[i];  in divvy_up_power()
363 		extra_actor_power[i] = max_power[i] - granted_power[i];  in divvy_up_power()
371 	 * Re-divvy the reclaimed extra among actors based on  in divvy_up_power()
387 	struct power_allocator_params *params = tz->governor_data;  in allocate_power()
393 	int trip_max_desired_temperature = params->trip_max_desired_temperature;  in allocate_power()
397 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allocate_power()
398 		if ((instance->trip == trip_max_desired_temperature) &&  in allocate_power()
399 		    cdev_is_power_actor(instance->cdev)) {  in allocate_power()
401 			total_weight += instance->weight;  in allocate_power()
406 		return -ENODEV;  in allocate_power()
421 		return -ENOMEM;  in allocate_power()
433 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allocate_power()
435 		struct thermal_cooling_device *cdev = instance->cdev;  in allocate_power()
437 		if (instance->trip != trip_max_desired_temperature)  in allocate_power()
443 		if (cdev->ops->get_requested_power(cdev, &req_power[i]))  in allocate_power()
449 			weight = instance->weight;  in allocate_power()
453 		if (cdev->ops->state2power(cdev, instance->lower,  in allocate_power()
472 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allocate_power()
473 		if (instance->trip != trip_max_desired_temperature)  in allocate_power()
476 		if (!cdev_is_power_actor(instance->cdev))  in allocate_power()
479 		power_actor_set_power(instance->cdev, instance,  in allocate_power()
489 				      max_allocatable_power, tz->temperature,  in allocate_power()
490 				      control_temp - tz->temperature);  in allocate_power()
498  * get_governor_trips() - get the number of the two trip points that are key for this governor
502  * The power allocator governor works optimally with two trips points:
522 	for (i = 0; i < tz->num_trips; i++) {  in get_governor_trips()
526 		ret = tz->ops->get_trip_type(tz, i, &type);  in get_governor_trips()
528 			dev_warn(&tz->device,  in get_governor_trips()
536 				params->trip_switch_on = i;  in get_governor_trips()
549 		params->trip_max_desired_temperature = last_passive;  in get_governor_trips()
551 		params->trip_max_desired_temperature = params->trip_switch_on;  in get_governor_trips()
552 		params->trip_switch_on = INVALID_TRIP;  in get_governor_trips()
554 		params->trip_switch_on = INVALID_TRIP;  in get_governor_trips()
555 		params->trip_max_desired_temperature = last_active;  in get_governor_trips()
561 	params->err_integral = 0;  in reset_pid_controller()
562 	params->prev_err = 0;  in reset_pid_controller()
568 	struct power_allocator_params *params = tz->governor_data;  in allow_maximum_power()
571 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allow_maximum_power()
572 		struct thermal_cooling_device *cdev = instance->cdev;  in allow_maximum_power()
574 		if ((instance->trip != params->trip_max_desired_temperature) ||  in allow_maximum_power()
575 		    (!cdev_is_power_actor(instance->cdev)))  in allow_maximum_power()
578 		instance->target = 0;  in allow_maximum_power()
579 		mutex_lock(&instance->cdev->lock);  in allow_maximum_power()
585 		cdev->ops->get_requested_power(cdev, &req_power);  in allow_maximum_power()
588 			__thermal_cdev_update(instance->cdev);  in allow_maximum_power()
590 		mutex_unlock(&instance->cdev->lock);  in allow_maximum_power()
595  * check_power_actors() - Check all cooling devices and warn when they are
596  *			not power actors
600  * power actor API. The warning should help to investigate the issue, which
603  * Return: 0 on success, -EINVAL if any cooling device does not implement
604  * the power actor API.
611 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in check_power_actors()
612 		if (!cdev_is_power_actor(instance->cdev)) {  in check_power_actors()
613 			dev_warn(&tz->device, "power_allocator: %s is not a power actor\n",  in check_power_actors()
614 				 instance->cdev->type);  in check_power_actors()
615 			ret = -EINVAL;  in check_power_actors()
623  * power_allocator_bind() - bind the power_allocator governor to a thermal zone
629  * Return: 0 on success, or -ENOMEM if we ran out of memory, or -EINVAL
644 		return -ENOMEM;  in power_allocator_bind()
646 	if (!tz->tzp) {  in power_allocator_bind()
647 		tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);  in power_allocator_bind()
648 		if (!tz->tzp) {  in power_allocator_bind()
649 			ret = -ENOMEM;  in power_allocator_bind()
653 		params->allocated_tzp = true;  in power_allocator_bind()
656 	if (!tz->tzp->sustainable_power)  in power_allocator_bind()
657 		dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");  in power_allocator_bind()
661 	if (tz->num_trips > 0) {  in power_allocator_bind()
662 		ret = tz->ops->get_trip_temp(tz,  in power_allocator_bind()
663 					params->trip_max_desired_temperature,  in power_allocator_bind()
666 			estimate_pid_constants(tz, tz->tzp->sustainable_power,  in power_allocator_bind()
667 					       params->trip_switch_on,  in power_allocator_bind()
673 	tz->governor_data = params;  in power_allocator_bind()
685 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_unbind()
687 	dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);  in power_allocator_unbind()
689 	if (params->allocated_tzp) {  in power_allocator_unbind()
690 		kfree(tz->tzp);  in power_allocator_unbind()
691 		tz->tzp = NULL;  in power_allocator_unbind()
694 	kfree(tz->governor_data);  in power_allocator_unbind()
695 	tz->governor_data = NULL;  in power_allocator_unbind()
702 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_throttle()
705 	lockdep_assert_held(&tz->lock);  in power_allocator_throttle()
711 	if (trip != params->trip_max_desired_temperature)  in power_allocator_throttle()
714 	ret = tz->ops->get_trip_temp(tz, params->trip_switch_on,  in power_allocator_throttle()
716 	if (!ret && (tz->temperature < switch_on_temp)) {  in power_allocator_throttle()
717 		update = (tz->last_temperature >= switch_on_temp);  in power_allocator_throttle()
718 		tz->passive = 0;  in power_allocator_throttle()
724 	tz->passive = 1;  in power_allocator_throttle()
726 	ret = tz->ops->get_trip_temp(tz, params->trip_max_desired_temperature,  in power_allocator_throttle()
729 		dev_warn(&tz->device,  in power_allocator_throttle()