1 // SPDX-License-Identifier: GPL-2.0
3  * drivers/base/power/domain_governor.c - Governors for device PM domains.
20 	if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {  in dev_update_qos_constraint()
22 		 * Only take suspend-time QoS constraints of devices into  in dev_update_qos_constraint()
28 		constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns;  in dev_update_qos_constraint()
31 		 * The child is not in a domain and there's no info on its  in dev_update_qos_constraint()
47  * default_suspend_ok - Default PM domain governor routine to suspend devices.
52 	struct gpd_timing_data *td = &dev_gpd_data(dev)->td;  in default_suspend_ok()
58 	spin_lock_irqsave(&dev->power.lock, flags);  in default_suspend_ok()
60 	if (!td->constraint_changed) {  in default_suspend_ok()
61 		bool ret = td->cached_suspend_ok;  in default_suspend_ok()
63 		spin_unlock_irqrestore(&dev->power.lock, flags);  in default_suspend_ok()
66 	td->constraint_changed = false;  in default_suspend_ok()
67 	td->cached_suspend_ok = false;  in default_suspend_ok()
68 	td->effective_constraint_ns = 0;  in default_suspend_ok()
71 	spin_unlock_irqrestore(&dev->power.lock, flags);  in default_suspend_ok()
82 	if (!dev->power.ignore_children)  in default_suspend_ok()
88 		td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;  in default_suspend_ok()
89 		td->cached_suspend_ok = true;  in default_suspend_ok()
93 		 * domain has a zero PM QoS constraint and it's better not to  in default_suspend_ok()
99 		constraint_ns -= td->suspend_latency_ns +  in default_suspend_ok()
100 				td->resume_latency_ns;  in default_suspend_ok()
109 		td->effective_constraint_ns = constraint_ns;  in default_suspend_ok()
110 		td->cached_suspend_ok = true;  in default_suspend_ok()
117 	return td->cached_suspend_ok;  in default_suspend_ok()
127 	if (!(genpd->flags & GENPD_FLAG_MIN_RESIDENCY))  in update_domain_next_wakeup()
133 	 * devices attached to this domain and from all the sub-domains.  in update_domain_next_wakeup()
135 	 * stale when we read that here. We will ignore to ensure the domain  in update_domain_next_wakeup()
136 	 * is able to enter its optimal idle state.  in update_domain_next_wakeup()
138 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {  in update_domain_next_wakeup()
139 		next_wakeup = to_gpd_data(pdd)->next_wakeup;  in update_domain_next_wakeup()
145 	list_for_each_entry(link, &genpd->parent_links, parent_node) {  in update_domain_next_wakeup()
146 		next_wakeup = link->child->next_wakeup;  in update_domain_next_wakeup()
152 	genpd->next_wakeup = domain_wakeup;  in update_domain_next_wakeup()
156 				     unsigned int state, ktime_t now)  in next_wakeup_allows_state()  argument
158 	ktime_t domain_wakeup = genpd->next_wakeup;  in next_wakeup_allows_state()
161 	min_sleep_ns = genpd->states[state].power_off_latency_ns +  in next_wakeup_allows_state()
162 		       genpd->states[state].residency_ns;  in next_wakeup_allows_state()
170 				     unsigned int state)  in __default_power_down_ok()  argument
178 	off_on_time_ns = genpd->states[state].power_off_latency_ns +  in __default_power_down_ok()
179 		genpd->states[state].power_on_latency_ns;  in __default_power_down_ok()
181 	min_off_time_ns = -1;  in __default_power_down_ok()
187 	list_for_each_entry(link, &genpd->parent_links, parent_node) {  in __default_power_down_ok()
188 		struct generic_pm_domain *sd = link->child;  in __default_power_down_ok()
189 		s64 sd_max_off_ns = sd->max_off_time_ns;  in __default_power_down_ok()
196 		 * the current domain to turn off and on (that's how much time  in __default_power_down_ok()
207 	 * Check if the devices in the domain can be off enough time.  in __default_power_down_ok()
209 	list_for_each_entry(pdd, &genpd->dev_list, list_node) {  in __default_power_down_ok()
215 		 * domain to turn off and on (that's how much time it will  in __default_power_down_ok()
218 		td = &to_gpd_data(pdd)->td;  in __default_power_down_ok()
219 		constraint_ns = td->effective_constraint_ns;  in __default_power_down_ok()
222 		 * devices in the domain are suspended, so it must be positive.  in __default_power_down_ok()
236 	 * latency constraints, so the domain can spend arbitrary time in the  in __default_power_down_ok()
237 	 * "off" state.  in __default_power_down_ok()
244 	 * time and the time needed to turn the domain on is the maximum  in __default_power_down_ok()
245 	 * theoretical time this domain can spend in the "off" state.  in __default_power_down_ok()
247 	genpd->max_off_time_ns = min_off_time_ns -  in __default_power_down_ok()
248 		genpd->states[state].power_on_latency_ns;  in __default_power_down_ok()
253  * _default_power_down_ok - Default generic PM domain power off governor routine.
254  * @pd: PM domain to check.
257  * This routine must be executed under the PM domain's lock.
262 	int state_idx = genpd->state_count - 1;  in _default_power_down_ok()
267 	 * to find when the domain would wakeup and do it for every device down  in _default_power_down_ok()
268 	 * the hierarchy. It is not worth while to sleep if the state's residency  in _default_power_down_ok()
272 	if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (genpd->next_wakeup != KTIME_MAX)) {  in _default_power_down_ok()
273 		/* Let's find out the deepest domain idle state, the devices prefer */  in _default_power_down_ok()
276 				genpd->max_off_time_changed = true;  in _default_power_down_ok()
279 			state_idx--;  in _default_power_down_ok()
284 			genpd->cached_power_down_ok = false;  in _default_power_down_ok()
289 	if (!genpd->max_off_time_changed) {  in _default_power_down_ok()
290 		genpd->state_idx = genpd->cached_power_down_state_idx;  in _default_power_down_ok()
291 		return genpd->cached_power_down_ok;  in _default_power_down_ok()
300 	list_for_each_entry(link, &genpd->child_links, child_node)  in _default_power_down_ok()
301 		link->parent->max_off_time_changed = true;  in _default_power_down_ok()
303 	genpd->max_off_time_ns = -1;  in _default_power_down_ok()
304 	genpd->max_off_time_changed = false;  in _default_power_down_ok()
305 	genpd->cached_power_down_ok = true;  in _default_power_down_ok()
308 	 * Find a state to power down to, starting from the state  in _default_power_down_ok()
313 			genpd->cached_power_down_ok = false;  in _default_power_down_ok()
316 		state_idx--;  in _default_power_down_ok()
320 	genpd->state_idx = state_idx;  in _default_power_down_ok()
321 	genpd->cached_power_down_state_idx = genpd->state_idx;  in _default_power_down_ok()
322 	return genpd->cached_power_down_ok;  in _default_power_down_ok()
330 static bool always_on_power_down_ok(struct dev_pm_domain *domain)  in always_on_power_down_ok()  argument
349 	if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))  in cpu_power_down_ok()
353 	 * Find the next wakeup for any of the online CPUs within the PM domain  in cpu_power_down_ok()
354 	 * and its subdomains. Note, we only need the genpd->cpus, as it already  in cpu_power_down_ok()
358 	for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {  in cpu_power_down_ok()
361 			next_hrtimer = READ_ONCE(dev->next_hrtimer);  in cpu_power_down_ok()
367 	/* The minimum idle duration is from now - until the next wakeup. */  in cpu_power_down_ok()
373 	 * Find the deepest idle state that has its residency value satisfied  in cpu_power_down_ok()
374 	 * and by also taking into account the power off latency for the state.  in cpu_power_down_ok()
375 	 * Start at the state picked by the dev PM QoS constraint validation.  in cpu_power_down_ok()
377 	i = genpd->state_idx;  in cpu_power_down_ok()
379 		if (idle_duration_ns >= (genpd->states[i].residency_ns +  in cpu_power_down_ok()
380 		    genpd->states[i].power_off_latency_ns)) {  in cpu_power_down_ok()
381 			genpd->state_idx = i;  in cpu_power_down_ok()
384 	} while (--i >= 0);  in cpu_power_down_ok()
401  * pm_genpd_gov_always_on - A governor implementing an always-on policy