1 // SPDX-License-Identifier: GPL-2.0
24  * mul_frac() - multiply two fixed-point numbers
28  * Return: the result of multiplying two fixed-point numbers.  The
29  * result is also a fixed-point number.
37  * div_frac() - divide two fixed-point numbers
41  * Return: the result of dividing two fixed-point numbers.  The
42  * result is also a fixed-point number.
50  * struct power_actor - internal power information for power actor
66  * struct power_allocator_params - parameters for the power allocator governor
75  * @trip_switch_on:	first passive trip point of the thermal zone.  The
76  *			governor switches on when this trip point is crossed.
77  *			If the thermal zone only has one passive trip point,
79  * @trip_max:		last passive trip point of the thermal zone. The
83  * @buffer_size:	internal buffer size, to avoid runtime re-calculation
102 	return cdev_is_power_actor(instance->cdev);  in power_actor_is_valid()
106  * estimate_sustainable_power() - Estimate the sustainable power of a thermal zone
118 	struct power_allocator_params *params = tz->governor_data;  in estimate_sustainable_power()
119 	const struct thermal_trip_desc *td = trip_to_trip_desc(params->trip_max);  in estimate_sustainable_power()
125 	list_for_each_entry(instance, &td->thermal_instances, trip_node) {  in estimate_sustainable_power()
129 		cdev = instance->cdev;  in estimate_sustainable_power()
130 		if (cdev->ops->state2power(cdev, instance->upper, &min_power))  in estimate_sustainable_power()
140  * estimate_pid_constants() - Estimate the constants for the PID controller
143  * @trip_switch_on:	trip point for the switch on temperature
158 		temperature_threshold -= trip_switch_on->temperature;  in estimate_pid_constants()
163 	 * system integrator has configured a thermal zone with two  in estimate_pid_constants()
171 	tz->tzp->k_po = int_to_frac(sustainable_power) /  in estimate_pid_constants()
174 	tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /  in estimate_pid_constants()
177 	k_i = tz->tzp->k_pu / 10;  in estimate_pid_constants()
178 	tz->tzp->k_i = k_i > 0 ? k_i : 1;  in estimate_pid_constants()
187  * get_sustainable_power() - Get the right sustainable power
203 	if (!tz->tzp->sustainable_power)  in get_sustainable_power()
206 		sustainable_power = tz->tzp->sustainable_power;  in get_sustainable_power()
209 	if (sustainable_power != params->sustainable_power) {  in get_sustainable_power()
211 				       params->trip_switch_on, control_temp);  in get_sustainable_power()
214 		tz->tzp->sustainable_power = sustainable_power;  in get_sustainable_power()
215 		params->sustainable_power = sustainable_power;  in get_sustainable_power()
222  * pid_controller() - PID controller
234  * the system warmer.  If the system is mostly idle, there's no point
243 	struct power_allocator_params *params = tz->governor_data;  in pid_controller()
252 	err = control_temp - tz->temperature;  in pid_controller()
256 	p = mul_frac(err < 0 ? tz->tzp->k_po : tz->tzp->k_pu, err);  in pid_controller()
264 	i = mul_frac(tz->tzp->k_i, params->err_integral);  in pid_controller()
266 	if (err < int_to_frac(tz->tzp->integral_cutoff)) {  in pid_controller()
267 		s64 i_next = i + mul_frac(tz->tzp->k_i, err);  in pid_controller()
271 			params->err_integral += err;  in pid_controller()
278 	 * We do err - prev_err, so with a positive k_d, a decreasing  in pid_controller()
282 	d = mul_frac(tz->tzp->k_d, err - params->prev_err);  in pid_controller()
283 	d = div_frac(d, jiffies_to_msecs(tz->passive_delay_jiffies));  in pid_controller()
284 	params->prev_err = err;  in pid_controller()
288 	/* feed-forward the known sustainable dissipatable power */  in pid_controller()
294 					  frac_to_int(params->err_integral),  in pid_controller()
302  * power_actor_set_power() - limit the maximum power a cooling device consumes
310  * Return: 0 on success, -EINVAL if the cooling device does not
311  * implement the power actor API or -E* for other failures.
320 	ret = cdev->ops->power2state(cdev, power, &state);  in power_actor_set_power()
324 	instance->target = clamp_val(state, instance->lower, instance->upper);  in power_actor_set_power()
332  * divvy_up_power() - divvy the allocated power between the actors
347  * surplus is re-divvied among the actors based on how far they are
365 			pa->granted_power = pa->max_power;  in divvy_up_power()
373 		u64 req_range = (u64)pa->weighted_req_power * power_range;  in divvy_up_power()
375 		pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,  in divvy_up_power()
378 		if (pa->granted_power > pa->max_power) {  in divvy_up_power()
379 			extra_power += pa->granted_power - pa->max_power;  in divvy_up_power()
380 			pa->granted_power = pa->max_power;  in divvy_up_power()
383 		pa->extra_actor_power = pa->max_power - pa->granted_power;  in divvy_up_power()
384 		capped_extra_power += pa->extra_actor_power;  in divvy_up_power()
391 	 * Re-divvy the reclaimed extra among actors based on  in divvy_up_power()
398 		u64 extra_range = pa->extra_actor_power;  in divvy_up_power()
401 		pa->granted_power += DIV_ROUND_CLOSEST_ULL(extra_range,  in divvy_up_power()
408 	struct power_allocator_params *params = tz->governor_data;  in allocate_power()
409 	const struct thermal_trip_desc *td = trip_to_trip_desc(params->trip_max);  in allocate_power()
410 	unsigned int num_actors = params->num_actors;  in allocate_power()
411 	struct power_actor *power = params->power;  in allocate_power()
425 	memset(power, 0, params->buffer_size);  in allocate_power()
427 	list_for_each_entry(instance, &td->thermal_instances, trip_node) {  in allocate_power()
433 		cdev = instance->cdev;  in allocate_power()
435 		ret = cdev->ops->get_requested_power(cdev, &pa->req_power);  in allocate_power()
439 		if (!params->total_weight)  in allocate_power()
442 			weight = instance->weight;  in allocate_power()
444 		pa->weighted_req_power = frac_to_int(weight * pa->req_power);  in allocate_power()
446 		ret = cdev->ops->state2power(cdev, instance->lower,  in allocate_power()
447 					     &pa->max_power);  in allocate_power()
451 		total_req_power += pa->req_power;  in allocate_power()
452 		max_allocatable_power += pa->max_power;  in allocate_power()
453 		total_weighted_req_power += pa->weighted_req_power;  in allocate_power()
464 	list_for_each_entry(instance, &td->thermal_instances, trip_node) {  in allocate_power()
470 		power_actor_set_power(instance->cdev, instance,  in allocate_power()
471 				      pa->granted_power);  in allocate_power()
472 		total_granted_power += pa->granted_power;  in allocate_power()
474 		trace_thermal_power_actor(tz, i, pa->req_power,  in allocate_power()
475 					  pa->granted_power);  in allocate_power()
481 				      max_allocatable_power, tz->temperature,  in allocate_power()
482 				      control_temp - tz->temperature);  in allocate_power()
486  * get_governor_trips() - get the two trip points that are key for this governor
490  * The power allocator governor works optimally with two trips points:
491  * a "switch on" trip point and a "maximum desired temperature".  These
494  * If there is only one trip point, then that's considered to be the
495  * "maximum desired temperature" trip point and the governor is always
509 		const struct thermal_trip *trip = &td->trip;  in get_governor_trips()
511 		switch (trip->type) {  in get_governor_trips()
528 		params->trip_switch_on = first_passive;  in get_governor_trips()
529 		params->trip_max = last_passive;  in get_governor_trips()
531 		params->trip_switch_on = NULL;  in get_governor_trips()
532 		params->trip_max = first_passive;  in get_governor_trips()
534 		params->trip_switch_on = NULL;  in get_governor_trips()
535 		params->trip_max = last_active;  in get_governor_trips()
541 	params->err_integral = 0;  in reset_pid_controller()
542 	params->prev_err = 0;  in reset_pid_controller()
547 	struct power_allocator_params *params = tz->governor_data;  in allow_maximum_power()
548 	const struct thermal_trip_desc *td = trip_to_trip_desc(params->trip_max);  in allow_maximum_power()
553 	list_for_each_entry(instance, &td->thermal_instances, trip_node) {  in allow_maximum_power()
557 		cdev = instance->cdev;  in allow_maximum_power()
559 		instance->target = 0;  in allow_maximum_power()
566 			cdev->ops->get_requested_power(cdev, &req_power);  in allow_maximum_power()
568 			if (params->update_cdevs)  in allow_maximum_power()
575  * check_power_actors() - Check all cooling devices and warn when they are
586  * devices may be attached later). Otherwise, return -EINVAL.
595 	if (!params->trip_max)  in check_power_actors()
598 	td = trip_to_trip_desc(params->trip_max);  in check_power_actors()
600 	list_for_each_entry(instance, &td->thermal_instances, trip_node) {  in check_power_actors()
601 		if (!cdev_is_power_actor(instance->cdev)) {  in check_power_actors()
602 			dev_warn(&tz->device, "power_allocator: %s is not a power actor\n",  in check_power_actors()
603 				 instance->cdev->type);  in check_power_actors()
604 			return -EINVAL;  in check_power_actors()
617 	kfree(params->power);  in allocate_actors_buffer()
625 	params->power = kcalloc(num_actors, sizeof(struct power_actor),  in allocate_actors_buffer()
627 	if (!params->power) {  in allocate_actors_buffer()
628 		ret = -ENOMEM;  in allocate_actors_buffer()
632 	params->num_actors = num_actors;  in allocate_actors_buffer()
633 	params->buffer_size = num_actors * sizeof(struct power_actor);  in allocate_actors_buffer()
638 	params->num_actors = 0;  in allocate_actors_buffer()
639 	params->buffer_size = 0;  in allocate_actors_buffer()
640 	params->power = NULL;  in allocate_actors_buffer()
649 	if (!params->trip_max)  in power_allocator_update_weight()
652 	td = trip_to_trip_desc(params->trip_max);  in power_allocator_update_weight()
654 	params->total_weight = 0;  in power_allocator_update_weight()
655 	list_for_each_entry(instance, &td->thermal_instances, trip_node)  in power_allocator_update_weight()
657 			params->total_weight += instance->weight;  in power_allocator_update_weight()
663 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_update_tz()
664 	const struct thermal_trip_desc *td = trip_to_trip_desc(params->trip_max);  in power_allocator_update_tz()
671 		list_for_each_entry(instance, &td->thermal_instances, trip_node)  in power_allocator_update_tz()
675 		if (num_actors != params->num_actors)  in power_allocator_update_tz()
688  * power_allocator_bind() - bind the power_allocator governor to a thermal zone
694  * Return: 0 on success, or -ENOMEM if we ran out of memory, or -EINVAL
704 		return -ENOMEM;  in power_allocator_bind()
710 		dev_warn(&tz->device, "power_allocator: binding failed\n");  in power_allocator_bind()
717 		dev_warn(&tz->device, "power_allocator: allocation failed\n");  in power_allocator_bind()
722 	if (!tz->tzp) {  in power_allocator_bind()
723 		tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);  in power_allocator_bind()
724 		if (!tz->tzp) {  in power_allocator_bind()
725 			ret = -ENOMEM;  in power_allocator_bind()
729 		params->allocated_tzp = true;  in power_allocator_bind()
732 	if (!tz->tzp->sustainable_power)  in power_allocator_bind()
733 		dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");  in power_allocator_bind()
735 		params->sustainable_power = tz->tzp->sustainable_power;  in power_allocator_bind()
737 	if (params->trip_max)  in power_allocator_bind()
738 		estimate_pid_constants(tz, tz->tzp->sustainable_power,  in power_allocator_bind()
739 				       params->trip_switch_on,  in power_allocator_bind()
740 				       params->trip_max->temperature);  in power_allocator_bind()
744 	tz->governor_data = params;  in power_allocator_bind()
751 	kfree(params->power);  in power_allocator_bind()
759 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_unbind()
761 	dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);  in power_allocator_unbind()
763 	if (params->allocated_tzp) {  in power_allocator_unbind()
764 		kfree(tz->tzp);  in power_allocator_unbind()
765 		tz->tzp = NULL;  in power_allocator_unbind()
768 	kfree(params->power);  in power_allocator_unbind()
769 	kfree(tz->governor_data);  in power_allocator_unbind()
770 	tz->governor_data = NULL;  in power_allocator_unbind()
775 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_manage()
776 	const struct thermal_trip *trip = params->trip_switch_on;  in power_allocator_manage()
778 	lockdep_assert_held(&tz->lock);  in power_allocator_manage()
780 	if (trip && tz->temperature < trip->temperature) {  in power_allocator_manage()
783 		params->update_cdevs = false;  in power_allocator_manage()
787 	if (!params->trip_max)  in power_allocator_manage()
790 	allocate_power(tz, params->trip_max->temperature);  in power_allocator_manage()
791 	params->update_cdevs = true;  in power_allocator_manage()