1 // SPDX-License-Identifier: GPL-2.0
3  * A power allocator to manage temperature
9 #define pr_fmt(fmt) "Power allocator: " fmt
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
51  * @req_power:		requested power value (not weighted)
52  * @max_power:		max allocatable power for this actor
53  * @granted_power:	granted power for this actor
54  * @extra_actor_power:	extra power that this actor can receive
55  * @weighted_req_power:	weighted requested power as input to IPA
66  * struct power_allocator_params - parameters for the power allocator governor
73  * @sustainable_power:	Sustainable power (heat) that this thermal zone can
83  * @buffer_size:	internal buffer size, to avoid runtime re-calculation
84  * @power:		buffer for all power actors internal power information
97 	struct power_actor *power;  member
103 	return (instance->trip == params->trip_max &&  in power_actor_is_valid()
104 		 cdev_is_power_actor(instance->cdev));  in power_actor_is_valid()
108  * estimate_sustainable_power() - Estimate the sustainable power of a thermal zone
113  * power of all the cooling devices as that gives a valid value that
120 	struct power_allocator_params *params = tz->governor_data;  in estimate_sustainable_power()
126 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in estimate_sustainable_power()
130 		cdev = instance->cdev;  in estimate_sustainable_power()
131 		if (cdev->ops->state2power(cdev, instance->upper, &min_power))  in estimate_sustainable_power()
141  * estimate_pid_constants() - Estimate the constants for the PID controller
143  * @sustainable_power:	sustainable power for the thermal zone
145  * @control_temp:	target temperature for the power allocator governor
159 		temperature_threshold -= trip_switch_on->temperature;  in estimate_pid_constants()
172 	tz->tzp->k_po = int_to_frac(sustainable_power) /  in estimate_pid_constants()
175 	tz->tzp->k_pu = int_to_frac(2 * sustainable_power) /  in estimate_pid_constants()
178 	k_i = tz->tzp->k_pu / 10;  in estimate_pid_constants()
179 	tz->tzp->k_i = k_i > 0 ? k_i : 1;  in estimate_pid_constants()
188  * get_sustainable_power() - Get the right sustainable power
190  * @params:	parameters for the power allocator governor
191  * @control_temp:	target temperature for the power allocator governor
193  * This function is used for getting the proper sustainable power value based
204 	if (!tz->tzp->sustainable_power)  in get_sustainable_power()
207 		sustainable_power = tz->tzp->sustainable_power;  in get_sustainable_power()
210 	if (sustainable_power != params->sustainable_power) {  in get_sustainable_power()
212 				       params->trip_switch_on, control_temp);  in get_sustainable_power()
215 		tz->tzp->sustainable_power = sustainable_power;  in get_sustainable_power()
216 		params->sustainable_power = sustainable_power;  in get_sustainable_power()
223  * pid_controller() - PID controller
226  * @max_allocatable_power:	maximum allocatable power for this thermal zone
228  * This PID controller increases the available power budget so that the
230  * @control_temp and limits the power if it exceeds it.  k_po is the
234  * accumulated error is only valid if the requested power will make
238  * Return: The power budget for the next period.
244 	struct power_allocator_params *params = tz->governor_data;  in pid_controller()
253 	err = control_temp - tz->temperature;  in pid_controller()
257 	p = mul_frac(err < 0 ? tz->tzp->k_po : tz->tzp->k_pu, err);  in pid_controller()
263 	 * the integral is limited to max power)  in pid_controller()
265 	i = mul_frac(tz->tzp->k_i, params->err_integral);  in pid_controller()
267 	if (err < int_to_frac(tz->tzp->integral_cutoff)) {  in pid_controller()
268 		s64 i_next = i + mul_frac(tz->tzp->k_i, err);  in pid_controller()
272 			params->err_integral += err;  in pid_controller()
279 	 * We do err - prev_err, so with a positive k_d, a decreasing  in pid_controller()
281 	 * power being applied, slowing down the controller)  in pid_controller()
283 	d = mul_frac(tz->tzp->k_d, err - params->prev_err);  in pid_controller()
284 	d = div_frac(d, jiffies_to_msecs(tz->passive_delay_jiffies));  in pid_controller()
285 	params->prev_err = err;  in pid_controller()
289 	/* feed-forward the known sustainable dissipatable power */  in pid_controller()
295 					  frac_to_int(params->err_integral),  in pid_controller()
303  * power_actor_set_power() - limit the maximum power a cooling device consumes
306  * @power:	the power in milliwatts
308  * Set the cooling device to consume at most @power milliwatts. The limit is
309  * expected to be a cap at the maximum power consumption.
311  * Return: 0 on success, -EINVAL if the cooling device does not
312  * implement the power actor API or -E* for other failures.
316 		      struct thermal_instance *instance, u32 power)  in power_actor_set_power()  argument
321 	ret = cdev->ops->power2state(cdev, power, &state);  in power_actor_set_power()
325 	instance->target = clamp_val(state, instance->lower, instance->upper);  in power_actor_set_power()
326 	mutex_lock(&cdev->lock);  in power_actor_set_power()
328 	mutex_unlock(&cdev->lock);  in power_actor_set_power()
334  * divvy_up_power() - divvy the allocated power between the actors
335  * @power:		buffer for all power actors internal power information
336  * @num_actors:		number of power actors in this thermal zone
337  * @total_req_power:	sum of all weighted requested power for all actors
338  * @power_range:	total allocated power
340  * This function divides the total allocated power (@power_range)
342  * share of the @power_range according to how much power it requested
344  * requests power, then it receives all the @power_range.  If
348  * If any actor received more than their maximum power, then that
349  * surplus is re-divvied among the actors based on how far they are
352 static void divvy_up_power(struct power_actor *power, int num_actors,  in divvy_up_power()  argument
360 	 * Prevent division by 0 if none of the actors request power.  in divvy_up_power()
366 		struct power_actor *pa = &power[i];  in divvy_up_power()
367 		u64 req_range = (u64)pa->req_power * power_range;  in divvy_up_power()
369 		pa->granted_power = DIV_ROUND_CLOSEST_ULL(req_range,  in divvy_up_power()
372 		if (pa->granted_power > pa->max_power) {  in divvy_up_power()
373 			extra_power += pa->granted_power - pa->max_power;  in divvy_up_power()
374 			pa->granted_power = pa->max_power;  in divvy_up_power()
377 		pa->extra_actor_power = pa->max_power - pa->granted_power;  in divvy_up_power()
378 		capped_extra_power += pa->extra_actor_power;  in divvy_up_power()
385 	 * Re-divvy the reclaimed extra among actors based on  in divvy_up_power()
391 		struct power_actor *pa = &power[i];  in divvy_up_power()
392 		u64 extra_range = pa->extra_actor_power;  in divvy_up_power()
395 		pa->granted_power += DIV_ROUND_CLOSEST_ULL(extra_range,  in divvy_up_power()
402 	struct power_allocator_params *params = tz->governor_data;  in allocate_power()
403 	unsigned int num_actors = params->num_actors;  in allocate_power()
404 	struct power_actor *power = params->power;  in allocate_power()  local
417 	/* Clean all buffers for new power estimations */  in allocate_power()
418 	memset(power, 0, params->buffer_size);  in allocate_power()
420 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allocate_power()
421 		struct power_actor *pa = &power[i];  in allocate_power()
426 		cdev = instance->cdev;  in allocate_power()
428 		ret = cdev->ops->get_requested_power(cdev, &pa->req_power);  in allocate_power()
432 		if (!params->total_weight)  in allocate_power()
435 			weight = instance->weight;  in allocate_power()
437 		pa->weighted_req_power = frac_to_int(weight * pa->req_power);  in allocate_power()
439 		ret = cdev->ops->state2power(cdev, instance->lower,  in allocate_power()
440 					     &pa->max_power);  in allocate_power()
444 		total_req_power += pa->req_power;  in allocate_power()
445 		max_allocatable_power += pa->max_power;  in allocate_power()
446 		total_weighted_req_power += pa->weighted_req_power;  in allocate_power()
453 	divvy_up_power(power, num_actors, total_weighted_req_power,  in allocate_power()
457 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allocate_power()
458 		struct power_actor *pa = &power[i];  in allocate_power()
463 		power_actor_set_power(instance->cdev, instance,  in allocate_power()
464 				      pa->granted_power);  in allocate_power()
465 		total_granted_power += pa->granted_power;  in allocate_power()
467 		trace_thermal_power_actor(tz, i, pa->req_power,  in allocate_power()
468 					  pa->granted_power);  in allocate_power()
474 				      max_allocatable_power, tz->temperature,  in allocate_power()
475 				      control_temp - tz->temperature);  in allocate_power()
479  * get_governor_trips() - get the two trip points that are key for this governor
483  * The power allocator governor works optimally with two trips points:
502 		const struct thermal_trip *trip = &td->trip;  in get_governor_trips()
504 		switch (trip->type) {  in get_governor_trips()
521 		params->trip_switch_on = first_passive;  in get_governor_trips()
522 		params->trip_max = last_passive;  in get_governor_trips()
524 		params->trip_switch_on = NULL;  in get_governor_trips()
525 		params->trip_max = first_passive;  in get_governor_trips()
527 		params->trip_switch_on = NULL;  in get_governor_trips()
528 		params->trip_max = last_active;  in get_governor_trips()
534 	params->err_integral = 0;  in reset_pid_controller()
535 	params->prev_err = 0;  in reset_pid_controller()
540 	struct power_allocator_params *params = tz->governor_data;  in allow_maximum_power()
545 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in allow_maximum_power()
549 		cdev = instance->cdev;  in allow_maximum_power()
551 		instance->target = 0;  in allow_maximum_power()
552 		mutex_lock(&cdev->lock);  in allow_maximum_power()
558 		cdev->ops->get_requested_power(cdev, &req_power);  in allow_maximum_power()
560 		if (params->update_cdevs)  in allow_maximum_power()
563 		mutex_unlock(&cdev->lock);  in allow_maximum_power()
568  * check_power_actors() - Check all cooling devices and warn when they are
569  *			not power actors
571  * @params:	power allocator private data
574  * power actor API. The warning should help to investigate the issue, which
577  * If all of the cooling devices currently attached to @tz implement the power
579  * devices may be attached later). Otherwise, return -EINVAL.
587 	list_for_each_entry(instance, &tz->thermal_instances, tz_node) {  in check_power_actors()
588 		if (instance->trip != params->trip_max)  in check_power_actors()
591 		if (!cdev_is_power_actor(instance->cdev)) {  in check_power_actors()
592 			dev_warn(&tz->device, "power_allocator: %s is not a power actor\n",  in check_power_actors()
593 				 instance->cdev->type);  in check_power_actors()
594 			return -EINVAL;  in check_power_actors()
607 	kfree(params->power);  in allocate_actors_buffer()
615 	params->power = kcalloc(num_actors, sizeof(struct power_actor),  in allocate_actors_buffer()
617 	if (!params->power) {  in allocate_actors_buffer()
618 		ret = -ENOMEM;  in allocate_actors_buffer()
622 	params->num_actors = num_actors;  in allocate_actors_buffer()
623 	params->buffer_size = num_actors * sizeof(struct power_actor);  in allocate_actors_buffer()
628 	params->num_actors = 0;  in allocate_actors_buffer()
629 	params->buffer_size = 0;  in allocate_actors_buffer()
630 	params->power = NULL;  in allocate_actors_buffer()
637 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_update_tz()
644 		list_for_each_entry(instance, &tz->thermal_instances, tz_node)  in power_allocator_update_tz()
648 		if (num_actors == params->num_actors)  in power_allocator_update_tz()
654 		params->total_weight = 0;  in power_allocator_update_tz()
655 		list_for_each_entry(instance, &tz->thermal_instances, tz_node)  in power_allocator_update_tz()
657 				params->total_weight += instance->weight;  in power_allocator_update_tz()
665  * power_allocator_bind() - bind the power_allocator governor to a thermal zone
671  * Return: 0 on success, or -ENOMEM if we ran out of memory, or -EINVAL
681 		return -ENOMEM;  in power_allocator_bind()
687 		dev_warn(&tz->device, "power_allocator: binding failed\n");  in power_allocator_bind()
694 		dev_warn(&tz->device, "power_allocator: allocation failed\n");  in power_allocator_bind()
699 	if (!tz->tzp) {  in power_allocator_bind()
700 		tz->tzp = kzalloc(sizeof(*tz->tzp), GFP_KERNEL);  in power_allocator_bind()
701 		if (!tz->tzp) {  in power_allocator_bind()
702 			ret = -ENOMEM;  in power_allocator_bind()
706 		params->allocated_tzp = true;  in power_allocator_bind()
709 	if (!tz->tzp->sustainable_power)  in power_allocator_bind()
710 		dev_warn(&tz->device, "power_allocator: sustainable_power will be estimated\n");  in power_allocator_bind()
712 		params->sustainable_power = tz->tzp->sustainable_power;  in power_allocator_bind()
714 	if (params->trip_max)  in power_allocator_bind()
715 		estimate_pid_constants(tz, tz->tzp->sustainable_power,  in power_allocator_bind()
716 				       params->trip_switch_on,  in power_allocator_bind()
717 				       params->trip_max->temperature);  in power_allocator_bind()
721 	tz->governor_data = params;  in power_allocator_bind()
726 	kfree(params->power);  in power_allocator_bind()
734 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_unbind()
736 	dev_dbg(&tz->device, "Unbinding from thermal zone %d\n", tz->id);  in power_allocator_unbind()
738 	if (params->allocated_tzp) {  in power_allocator_unbind()
739 		kfree(tz->tzp);  in power_allocator_unbind()
740 		tz->tzp = NULL;  in power_allocator_unbind()
743 	kfree(params->power);  in power_allocator_unbind()
744 	kfree(tz->governor_data);  in power_allocator_unbind()
745 	tz->governor_data = NULL;  in power_allocator_unbind()
750 	struct power_allocator_params *params = tz->governor_data;  in power_allocator_manage()
751 	const struct thermal_trip *trip = params->trip_switch_on;  in power_allocator_manage()
753 	lockdep_assert_held(&tz->lock);  in power_allocator_manage()
755 	if (trip && tz->temperature < trip->temperature) {  in power_allocator_manage()
758 		params->update_cdevs = false;  in power_allocator_manage()
762 	if (!params->trip_max)  in power_allocator_manage()
765 	allocate_power(tz, params->trip_max->temperature);  in power_allocator_manage()
766 	params->update_cdevs = true;  in power_allocator_manage()