1 // SPDX-License-Identifier: GPL-2.0
3  * drivers/base/power/domain_governor.c - Governors for device PM domains.
21 	if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {  in dev_update_qos_constraint()
22 		struct gpd_timing_data *td = dev_gpd_data(dev)->td;  in dev_update_qos_constraint()
25 		 * Only take suspend-time QoS constraints of devices into  in dev_update_qos_constraint()
31 		constraint_ns = td ? td->effective_constraint_ns :  in dev_update_qos_constraint()
35 		 * The child is not in a domain and there's no info on its  in dev_update_qos_constraint()
51  * default_suspend_ok - Default PM domain governor routine to suspend devices.
58 	struct gpd_timing_data *td = dev_gpd_data(dev)->td;  in default_suspend_ok()
64 	spin_lock_irqsave(&dev->power.lock, flags);  in default_suspend_ok()
66 	if (!td->constraint_changed) {  in default_suspend_ok()
67 		bool ret = td->cached_suspend_ok;  in default_suspend_ok()
69 		spin_unlock_irqrestore(&dev->power.lock, flags);  in default_suspend_ok()
72 	td->constraint_changed = false;  in default_suspend_ok()
73 	td->cached_suspend_ok = false;  in default_suspend_ok()
74 	td->effective_constraint_ns = 0;  in default_suspend_ok()
77 	spin_unlock_irqrestore(&dev->power.lock, flags);  in default_suspend_ok()
88 	if (!dev->power.ignore_children)  in default_suspend_ok()
94 		td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;  in default_suspend_ok()
95 		td->cached_suspend_ok = true;  in default_suspend_ok()
99 		 * domain has a zero PM QoS constraint and it's better not to  in default_suspend_ok()
105 		constraint_ns -= td->suspend_latency_ns +  in default_suspend_ok()
106 				td->resume_latency_ns;  in default_suspend_ok()
115 		td->effective_constraint_ns = constraint_ns;  in default_suspend_ok()
116 		td->cached_suspend_ok = true;  in default_suspend_ok()
123 	return td->cached_suspend_ok;  in default_suspend_ok()
133 	if (!(genpd->flags & GENPD_FLAG_MIN_RESIDENCY))  in update_domain_next_wakeup()
139 	 * devices attached to this domain and from all the sub-domains.  in update_domain_next_wakeup()
141 	 * stale when we read that here. We will ignore to ensure the domain  in update_domain_next_wakeup()
142 	 * is able to enter its optimal idle state.  in update_domain_next_wakeup()
144 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {  in update_domain_next_wakeup()
145 		next_wakeup = to_gpd_data(pdd)->td->next_wakeup;  in update_domain_next_wakeup()
151 	list_for_each_entry(link, &genpd->parent_links, parent_node) {  in update_domain_next_wakeup()
152 		struct genpd_governor_data *cgd = link->child->gd;  in update_domain_next_wakeup()
154 		next_wakeup = cgd ? cgd->next_wakeup : KTIME_MAX;  in update_domain_next_wakeup()
160 	genpd->gd->next_wakeup = domain_wakeup;  in update_domain_next_wakeup()
164 				     unsigned int state, ktime_t now)  in next_wakeup_allows_state()  argument
166 	ktime_t domain_wakeup = genpd->gd->next_wakeup;  in next_wakeup_allows_state()
169 	min_sleep_ns = genpd->states[state].power_off_latency_ns +  in next_wakeup_allows_state()
170 		       genpd->states[state].residency_ns;  in next_wakeup_allows_state()
178 				     unsigned int state)  in __default_power_down_ok()  argument
186 	off_on_time_ns = genpd->states[state].power_off_latency_ns +  in __default_power_down_ok()
187 		genpd->states[state].power_on_latency_ns;  in __default_power_down_ok()
189 	min_off_time_ns = -1;  in __default_power_down_ok()
195 	list_for_each_entry(link, &genpd->parent_links, parent_node) {  in __default_power_down_ok()
196 		struct genpd_governor_data *cgd = link->child->gd;  in __default_power_down_ok()
198 		s64 sd_max_off_ns = cgd ? cgd->max_off_time_ns : -1;  in __default_power_down_ok()
205 		 * the current domain to turn off and on (that's how much time  in __default_power_down_ok()
216 	 * Check if the devices in the domain can be off enough time.  in __default_power_down_ok()
218 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {  in __default_power_down_ok()
224 		 * domain to turn off and on (that's how much time it will  in __default_power_down_ok()
227 		td = to_gpd_data(pdd)->td;  in __default_power_down_ok()
228 		constraint_ns = td->effective_constraint_ns;  in __default_power_down_ok()
231 		 * devices in the domain are suspended, so it must be positive.  in __default_power_down_ok()
245 	 * latency constraints, so the domain can spend arbitrary time in the  in __default_power_down_ok()
246 	 * "off" state.  in __default_power_down_ok()
253 	 * time and the time needed to turn the domain on is the maximum  in __default_power_down_ok()
254 	 * theoretical time this domain can spend in the "off" state.  in __default_power_down_ok()
256 	genpd->gd->max_off_time_ns = min_off_time_ns -  in __default_power_down_ok()
257 		genpd->states[state].power_on_latency_ns;  in __default_power_down_ok()
262  * _default_power_down_ok - Default generic PM domain power off governor routine.
263  * @pd: PM domain to check.
266  * This routine must be executed under the PM domain's lock.
273 	struct genpd_governor_data *gd = genpd->gd;  in _default_power_down_ok()
274 	int state_idx = genpd->state_count - 1;  in _default_power_down_ok()
279 	 * to find when the domain would wakeup and do it for every device down  in _default_power_down_ok()
280 	 * the hierarchy. It is not worth while to sleep if the state's residency  in _default_power_down_ok()
284 	if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (gd->next_wakeup != KTIME_MAX)) {  in _default_power_down_ok()
285 		/* Let's find out the deepest domain idle state, the devices prefer */  in _default_power_down_ok()
288 				gd->max_off_time_changed = true;  in _default_power_down_ok()
291 			state_idx--;  in _default_power_down_ok()
296 			gd->cached_power_down_ok = false;  in _default_power_down_ok()
301 	if (!gd->max_off_time_changed) {  in _default_power_down_ok()
302 		genpd->state_idx = gd->cached_power_down_state_idx;  in _default_power_down_ok()
303 		return gd->cached_power_down_ok;  in _default_power_down_ok()
312 	list_for_each_entry(link, &genpd->child_links, child_node) {  in _default_power_down_ok()
313 		struct genpd_governor_data *pgd = link->parent->gd;  in _default_power_down_ok()
316 			pgd->max_off_time_changed = true;  in _default_power_down_ok()
319 	gd->max_off_time_ns = -1;  in _default_power_down_ok()
320 	gd->max_off_time_changed = false;  in _default_power_down_ok()
321 	gd->cached_power_down_ok = true;  in _default_power_down_ok()
324 	 * Find a state to power down to, starting from the state  in _default_power_down_ok()
329 			gd->cached_power_down_ok = false;  in _default_power_down_ok()
332 		state_idx--;  in _default_power_down_ok()
336 	genpd->state_idx = state_idx;  in _default_power_down_ok()
337 	gd->cached_power_down_state_idx = genpd->state_idx;  in _default_power_down_ok()
338 	return gd->cached_power_down_ok;  in _default_power_down_ok()
362 	if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))  in cpu_power_down_ok()
367 	 * Find the next wakeup for any of the online CPUs within the PM domain  in cpu_power_down_ok()
368 	 * and its subdomains. Note, we only need the genpd->cpus, as it already  in cpu_power_down_ok()
372 	for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {  in cpu_power_down_ok()
375 			next_hrtimer = READ_ONCE(dev->next_hrtimer);  in cpu_power_down_ok()
389 	/* The minimum idle duration is from now - until the next wakeup. */  in cpu_power_down_ok()
395 	genpd->gd->next_hrtimer = domain_wakeup;  in cpu_power_down_ok()
398 	 * Find the deepest idle state that has its residency value satisfied  in cpu_power_down_ok()
399 	 * and by also taking into account the power off latency for the state.  in cpu_power_down_ok()
400 	 * Start at the state picked by the dev PM QoS constraint validation.  in cpu_power_down_ok()
402 	i = genpd->state_idx;  in cpu_power_down_ok()
404 		if ((idle_duration_ns >= (genpd->states[i].residency_ns +  in cpu_power_down_ok()
405 		    genpd->states[i].power_off_latency_ns)) &&  in cpu_power_down_ok()
406 		    (global_constraint >= (genpd->states[i].power_on_latency_ns +  in cpu_power_down_ok()
407 		    genpd->states[i].power_off_latency_ns))) {  in cpu_power_down_ok()
408 			genpd->state_idx = i;  in cpu_power_down_ok()
409 			genpd->gd->last_enter = now;  in cpu_power_down_ok()
410 			genpd->gd->reflect_residency = true;  in cpu_power_down_ok()
413 	} while (--i >= 0);  in cpu_power_down_ok()
430  * pm_domain_always_on_gov - A governor implementing an always-on policy