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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/power/domain_governor.c - Governors for device PM domains.
4 *
5 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
6 */
7#include <linux/kernel.h>
8#include <linux/pm_domain.h>
9#include <linux/pm_qos.h>
10#include <linux/hrtimer.h>
11#include <linux/cpuidle.h>
12#include <linux/cpumask.h>
13#include <linux/ktime.h>
14
15static int dev_update_qos_constraint(struct device *dev, void *data)
16{
17 s64 *constraint_ns_p = data;
18 s64 constraint_ns;
19
20 if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {
21 /*
22 * Only take suspend-time QoS constraints of devices into
23 * account, because constraints updated after the device has
24 * been suspended are not guaranteed to be taken into account
25 * anyway. In order for them to take effect, the device has to
26 * be resumed and suspended again.
27 */
28 constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns;
29 } else {
30 /*
31 * The child is not in a domain and there's no info on its
32 * suspend/resume latencies, so assume them to be negligible and
33 * take its current PM QoS constraint (that's the only thing
34 * known at this point anyway).
35 */
36 constraint_ns = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
37 constraint_ns *= NSEC_PER_USEC;
38 }
39
40 if (constraint_ns < *constraint_ns_p)
41 *constraint_ns_p = constraint_ns;
42
43 return 0;
44}
45
46/**
47 * default_suspend_ok - Default PM domain governor routine to suspend devices.
48 * @dev: Device to check.
49 */
50static bool default_suspend_ok(struct device *dev)
51{
52 struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
53 unsigned long flags;
54 s64 constraint_ns;
55
56 dev_dbg(dev, "%s()\n", __func__);
57
58 spin_lock_irqsave(&dev->power.lock, flags);
59
60 if (!td->constraint_changed) {
61 bool ret = td->cached_suspend_ok;
62
63 spin_unlock_irqrestore(&dev->power.lock, flags);
64 return ret;
65 }
66 td->constraint_changed = false;
67 td->cached_suspend_ok = false;
68 td->effective_constraint_ns = 0;
69 constraint_ns = __dev_pm_qos_resume_latency(dev);
70
71 spin_unlock_irqrestore(&dev->power.lock, flags);
72
73 if (constraint_ns == 0)
74 return false;
75
76 constraint_ns *= NSEC_PER_USEC;
77 /*
78 * We can walk the children without any additional locking, because
79 * they all have been suspended at this point and their
80 * effective_constraint_ns fields won't be modified in parallel with us.
81 */
82 if (!dev->power.ignore_children)
83 device_for_each_child(dev, &constraint_ns,
84 dev_update_qos_constraint);
85
86 if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS) {
87 /* "No restriction", so the device is allowed to suspend. */
88 td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
89 td->cached_suspend_ok = true;
90 } else if (constraint_ns == 0) {
91 /*
92 * This triggers if one of the children that don't belong to a
93 * domain has a zero PM QoS constraint and it's better not to
94 * suspend then. effective_constraint_ns is zero already and
95 * cached_suspend_ok is false, so bail out.
96 */
97 return false;
98 } else {
99 constraint_ns -= td->suspend_latency_ns +
100 td->resume_latency_ns;
101 /*
102 * effective_constraint_ns is zero already and cached_suspend_ok
103 * is false, so if the computed value is not positive, return
104 * right away.
105 */
106 if (constraint_ns <= 0)
107 return false;
108
109 td->effective_constraint_ns = constraint_ns;
110 td->cached_suspend_ok = true;
111 }
112
113 /*
114 * The children have been suspended already, so we don't need to take
115 * their suspend latencies into account here.
116 */
117 return td->cached_suspend_ok;
118}
119
120static void update_domain_next_wakeup(struct generic_pm_domain *genpd, ktime_t now)
121{
122 ktime_t domain_wakeup = KTIME_MAX;
123 ktime_t next_wakeup;
124 struct pm_domain_data *pdd;
125 struct gpd_link *link;
126
127 if (!(genpd->flags & GENPD_FLAG_MIN_RESIDENCY))
128 return;
129
130 /*
131 * Devices that have a predictable wakeup pattern, may specify
132 * their next wakeup. Let's find the next wakeup from all the
133 * devices attached to this domain and from all the sub-domains.
134 * It is possible that component's a next wakeup may have become
135 * stale when we read that here. We will ignore to ensure the domain
136 * is able to enter its optimal idle state.
137 */
138 list_for_each_entry(pdd, &genpd->dev_list, list_node) {
139 next_wakeup = to_gpd_data(pdd)->next_wakeup;
140 if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
141 if (ktime_before(next_wakeup, domain_wakeup))
142 domain_wakeup = next_wakeup;
143 }
144
145 list_for_each_entry(link, &genpd->parent_links, parent_node) {
146 next_wakeup = link->child->next_wakeup;
147 if (next_wakeup != KTIME_MAX && !ktime_before(next_wakeup, now))
148 if (ktime_before(next_wakeup, domain_wakeup))
149 domain_wakeup = next_wakeup;
150 }
151
152 genpd->next_wakeup = domain_wakeup;
153}
154
155static bool next_wakeup_allows_state(struct generic_pm_domain *genpd,
156 unsigned int state, ktime_t now)
157{
158 ktime_t domain_wakeup = genpd->next_wakeup;
159 s64 idle_time_ns, min_sleep_ns;
160
161 min_sleep_ns = genpd->states[state].power_off_latency_ns +
162 genpd->states[state].residency_ns;
163
164 idle_time_ns = ktime_to_ns(ktime_sub(domain_wakeup, now));
165
166 return idle_time_ns >= min_sleep_ns;
167}
168
169static bool __default_power_down_ok(struct dev_pm_domain *pd,
170 unsigned int state)
171{
172 struct generic_pm_domain *genpd = pd_to_genpd(pd);
173 struct gpd_link *link;
174 struct pm_domain_data *pdd;
175 s64 min_off_time_ns;
176 s64 off_on_time_ns;
177
178 off_on_time_ns = genpd->states[state].power_off_latency_ns +
179 genpd->states[state].power_on_latency_ns;
180
181 min_off_time_ns = -1;
182 /*
183 * Check if subdomains can be off for enough time.
184 *
185 * All subdomains have been powered off already at this point.
186 */
187 list_for_each_entry(link, &genpd->parent_links, parent_node) {
188 struct generic_pm_domain *sd = link->child;
189 s64 sd_max_off_ns = sd->max_off_time_ns;
190
191 if (sd_max_off_ns < 0)
192 continue;
193
194 /*
195 * Check if the subdomain is allowed to be off long enough for
196 * the current domain to turn off and on (that's how much time
197 * it will have to wait worst case).
198 */
199 if (sd_max_off_ns <= off_on_time_ns)
200 return false;
201
202 if (min_off_time_ns > sd_max_off_ns || min_off_time_ns < 0)
203 min_off_time_ns = sd_max_off_ns;
204 }
205
206 /*
207 * Check if the devices in the domain can be off enough time.
208 */
209 list_for_each_entry(pdd, &genpd->dev_list, list_node) {
210 struct gpd_timing_data *td;
211 s64 constraint_ns;
212
213 /*
214 * Check if the device is allowed to be off long enough for the
215 * domain to turn off and on (that's how much time it will
216 * have to wait worst case).
217 */
218 td = &to_gpd_data(pdd)->td;
219 constraint_ns = td->effective_constraint_ns;
220 /*
221 * Zero means "no suspend at all" and this runs only when all
222 * devices in the domain are suspended, so it must be positive.
223 */
224 if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS)
225 continue;
226
227 if (constraint_ns <= off_on_time_ns)
228 return false;
229
230 if (min_off_time_ns > constraint_ns || min_off_time_ns < 0)
231 min_off_time_ns = constraint_ns;
232 }
233
234 /*
235 * If the computed minimum device off time is negative, there are no
236 * latency constraints, so the domain can spend arbitrary time in the
237 * "off" state.
238 */
239 if (min_off_time_ns < 0)
240 return true;
241
242 /*
243 * The difference between the computed minimum subdomain or device off
244 * time and the time needed to turn the domain on is the maximum
245 * theoretical time this domain can spend in the "off" state.
246 */
247 genpd->max_off_time_ns = min_off_time_ns -
248 genpd->states[state].power_on_latency_ns;
249 return true;
250}
251
252/**
253 * _default_power_down_ok - Default generic PM domain power off governor routine.
254 * @pd: PM domain to check.
255 * @now: current ktime.
256 *
257 * This routine must be executed under the PM domain's lock.
258 */
259static bool _default_power_down_ok(struct dev_pm_domain *pd, ktime_t now)
260{
261 struct generic_pm_domain *genpd = pd_to_genpd(pd);
262 int state_idx = genpd->state_count - 1;
263 struct gpd_link *link;
264
265 /*
266 * Find the next wakeup from devices that can determine their own wakeup
267 * to find when the domain would wakeup and do it for every device down
268 * the hierarchy. It is not worth while to sleep if the state's residency
269 * cannot be met.
270 */
271 update_domain_next_wakeup(genpd, now);
272 if ((genpd->flags & GENPD_FLAG_MIN_RESIDENCY) && (genpd->next_wakeup != KTIME_MAX)) {
273 /* Let's find out the deepest domain idle state, the devices prefer */
274 while (state_idx >= 0) {
275 if (next_wakeup_allows_state(genpd, state_idx, now)) {
276 genpd->max_off_time_changed = true;
277 break;
278 }
279 state_idx--;
280 }
281
282 if (state_idx < 0) {
283 state_idx = 0;
284 genpd->cached_power_down_ok = false;
285 goto done;
286 }
287 }
288
289 if (!genpd->max_off_time_changed) {
290 genpd->state_idx = genpd->cached_power_down_state_idx;
291 return genpd->cached_power_down_ok;
292 }
293
294 /*
295 * We have to invalidate the cached results for the parents, so
296 * use the observation that default_power_down_ok() is not
297 * going to be called for any parent until this instance
298 * returns.
299 */
300 list_for_each_entry(link, &genpd->child_links, child_node)
301 link->parent->max_off_time_changed = true;
302
303 genpd->max_off_time_ns = -1;
304 genpd->max_off_time_changed = false;
305 genpd->cached_power_down_ok = true;
306
307 /*
308 * Find a state to power down to, starting from the state
309 * determined by the next wakeup.
310 */
311 while (!__default_power_down_ok(pd, state_idx)) {
312 if (state_idx == 0) {
313 genpd->cached_power_down_ok = false;
314 break;
315 }
316 state_idx--;
317 }
318
319done:
320 genpd->state_idx = state_idx;
321 genpd->cached_power_down_state_idx = genpd->state_idx;
322 return genpd->cached_power_down_ok;
323}
324
325static bool default_power_down_ok(struct dev_pm_domain *pd)
326{
327 return _default_power_down_ok(pd, ktime_get());
328}
329
330static bool always_on_power_down_ok(struct dev_pm_domain *domain)
331{
332 return false;
333}
334
335#ifdef CONFIG_CPU_IDLE
336static bool cpu_power_down_ok(struct dev_pm_domain *pd)
337{
338 struct generic_pm_domain *genpd = pd_to_genpd(pd);
339 struct cpuidle_device *dev;
340 ktime_t domain_wakeup, next_hrtimer;
341 ktime_t now = ktime_get();
342 s64 idle_duration_ns;
343 int cpu, i;
344
345 /* Validate dev PM QoS constraints. */
346 if (!_default_power_down_ok(pd, now))
347 return false;
348
349 if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
350 return true;
351
352 /*
353 * Find the next wakeup for any of the online CPUs within the PM domain
354 * and its subdomains. Note, we only need the genpd->cpus, as it already
355 * contains a mask of all CPUs from subdomains.
356 */
357 domain_wakeup = ktime_set(KTIME_SEC_MAX, 0);
358 for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {
359 dev = per_cpu(cpuidle_devices, cpu);
360 if (dev) {
361 next_hrtimer = READ_ONCE(dev->next_hrtimer);
362 if (ktime_before(next_hrtimer, domain_wakeup))
363 domain_wakeup = next_hrtimer;
364 }
365 }
366
367 /* The minimum idle duration is from now - until the next wakeup. */
368 idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, now));
369 if (idle_duration_ns <= 0)
370 return false;
371
372 /*
373 * Find the deepest idle state that has its residency value satisfied
374 * and by also taking into account the power off latency for the state.
375 * Start at the state picked by the dev PM QoS constraint validation.
376 */
377 i = genpd->state_idx;
378 do {
379 if (idle_duration_ns >= (genpd->states[i].residency_ns +
380 genpd->states[i].power_off_latency_ns)) {
381 genpd->state_idx = i;
382 return true;
383 }
384 } while (--i >= 0);
385
386 return false;
387}
388
389struct dev_power_governor pm_domain_cpu_gov = {
390 .suspend_ok = default_suspend_ok,
391 .power_down_ok = cpu_power_down_ok,
392};
393#endif
394
395struct dev_power_governor simple_qos_governor = {
396 .suspend_ok = default_suspend_ok,
397 .power_down_ok = default_power_down_ok,
398};
399
400/**
401 * pm_genpd_gov_always_on - A governor implementing an always-on policy
402 */
403struct dev_power_governor pm_domain_always_on_gov = {
404 .power_down_ok = always_on_power_down_ok,
405 .suspend_ok = default_suspend_ok,
406};
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * drivers/base/power/domain_governor.c - Governors for device PM domains.
4 *
5 * Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
6 */
7#include <linux/kernel.h>
8#include <linux/pm_domain.h>
9#include <linux/pm_qos.h>
10#include <linux/hrtimer.h>
11#include <linux/cpuidle.h>
12#include <linux/cpumask.h>
13#include <linux/ktime.h>
14
15static int dev_update_qos_constraint(struct device *dev, void *data)
16{
17 s64 *constraint_ns_p = data;
18 s64 constraint_ns;
19
20 if (dev->power.subsys_data && dev->power.subsys_data->domain_data) {
21 /*
22 * Only take suspend-time QoS constraints of devices into
23 * account, because constraints updated after the device has
24 * been suspended are not guaranteed to be taken into account
25 * anyway. In order for them to take effect, the device has to
26 * be resumed and suspended again.
27 */
28 constraint_ns = dev_gpd_data(dev)->td.effective_constraint_ns;
29 } else {
30 /*
31 * The child is not in a domain and there's no info on its
32 * suspend/resume latencies, so assume them to be negligible and
33 * take its current PM QoS constraint (that's the only thing
34 * known at this point anyway).
35 */
36 constraint_ns = dev_pm_qos_read_value(dev, DEV_PM_QOS_RESUME_LATENCY);
37 constraint_ns *= NSEC_PER_USEC;
38 }
39
40 if (constraint_ns < *constraint_ns_p)
41 *constraint_ns_p = constraint_ns;
42
43 return 0;
44}
45
46/**
47 * default_suspend_ok - Default PM domain governor routine to suspend devices.
48 * @dev: Device to check.
49 */
50static bool default_suspend_ok(struct device *dev)
51{
52 struct gpd_timing_data *td = &dev_gpd_data(dev)->td;
53 unsigned long flags;
54 s64 constraint_ns;
55
56 dev_dbg(dev, "%s()\n", __func__);
57
58 spin_lock_irqsave(&dev->power.lock, flags);
59
60 if (!td->constraint_changed) {
61 bool ret = td->cached_suspend_ok;
62
63 spin_unlock_irqrestore(&dev->power.lock, flags);
64 return ret;
65 }
66 td->constraint_changed = false;
67 td->cached_suspend_ok = false;
68 td->effective_constraint_ns = 0;
69 constraint_ns = __dev_pm_qos_resume_latency(dev);
70
71 spin_unlock_irqrestore(&dev->power.lock, flags);
72
73 if (constraint_ns == 0)
74 return false;
75
76 constraint_ns *= NSEC_PER_USEC;
77 /*
78 * We can walk the children without any additional locking, because
79 * they all have been suspended at this point and their
80 * effective_constraint_ns fields won't be modified in parallel with us.
81 */
82 if (!dev->power.ignore_children)
83 device_for_each_child(dev, &constraint_ns,
84 dev_update_qos_constraint);
85
86 if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS) {
87 /* "No restriction", so the device is allowed to suspend. */
88 td->effective_constraint_ns = PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS;
89 td->cached_suspend_ok = true;
90 } else if (constraint_ns == 0) {
91 /*
92 * This triggers if one of the children that don't belong to a
93 * domain has a zero PM QoS constraint and it's better not to
94 * suspend then. effective_constraint_ns is zero already and
95 * cached_suspend_ok is false, so bail out.
96 */
97 return false;
98 } else {
99 constraint_ns -= td->suspend_latency_ns +
100 td->resume_latency_ns;
101 /*
102 * effective_constraint_ns is zero already and cached_suspend_ok
103 * is false, so if the computed value is not positive, return
104 * right away.
105 */
106 if (constraint_ns <= 0)
107 return false;
108
109 td->effective_constraint_ns = constraint_ns;
110 td->cached_suspend_ok = true;
111 }
112
113 /*
114 * The children have been suspended already, so we don't need to take
115 * their suspend latencies into account here.
116 */
117 return td->cached_suspend_ok;
118}
119
120static bool __default_power_down_ok(struct dev_pm_domain *pd,
121 unsigned int state)
122{
123 struct generic_pm_domain *genpd = pd_to_genpd(pd);
124 struct gpd_link *link;
125 struct pm_domain_data *pdd;
126 s64 min_off_time_ns;
127 s64 off_on_time_ns;
128
129 off_on_time_ns = genpd->states[state].power_off_latency_ns +
130 genpd->states[state].power_on_latency_ns;
131
132 min_off_time_ns = -1;
133 /*
134 * Check if subdomains can be off for enough time.
135 *
136 * All subdomains have been powered off already at this point.
137 */
138 list_for_each_entry(link, &genpd->master_links, master_node) {
139 struct generic_pm_domain *sd = link->slave;
140 s64 sd_max_off_ns = sd->max_off_time_ns;
141
142 if (sd_max_off_ns < 0)
143 continue;
144
145 /*
146 * Check if the subdomain is allowed to be off long enough for
147 * the current domain to turn off and on (that's how much time
148 * it will have to wait worst case).
149 */
150 if (sd_max_off_ns <= off_on_time_ns)
151 return false;
152
153 if (min_off_time_ns > sd_max_off_ns || min_off_time_ns < 0)
154 min_off_time_ns = sd_max_off_ns;
155 }
156
157 /*
158 * Check if the devices in the domain can be off enough time.
159 */
160 list_for_each_entry(pdd, &genpd->dev_list, list_node) {
161 struct gpd_timing_data *td;
162 s64 constraint_ns;
163
164 /*
165 * Check if the device is allowed to be off long enough for the
166 * domain to turn off and on (that's how much time it will
167 * have to wait worst case).
168 */
169 td = &to_gpd_data(pdd)->td;
170 constraint_ns = td->effective_constraint_ns;
171 /*
172 * Zero means "no suspend at all" and this runs only when all
173 * devices in the domain are suspended, so it must be positive.
174 */
175 if (constraint_ns == PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS)
176 continue;
177
178 if (constraint_ns <= off_on_time_ns)
179 return false;
180
181 if (min_off_time_ns > constraint_ns || min_off_time_ns < 0)
182 min_off_time_ns = constraint_ns;
183 }
184
185 /*
186 * If the computed minimum device off time is negative, there are no
187 * latency constraints, so the domain can spend arbitrary time in the
188 * "off" state.
189 */
190 if (min_off_time_ns < 0)
191 return true;
192
193 /*
194 * The difference between the computed minimum subdomain or device off
195 * time and the time needed to turn the domain on is the maximum
196 * theoretical time this domain can spend in the "off" state.
197 */
198 genpd->max_off_time_ns = min_off_time_ns -
199 genpd->states[state].power_on_latency_ns;
200 return true;
201}
202
203/**
204 * default_power_down_ok - Default generic PM domain power off governor routine.
205 * @pd: PM domain to check.
206 *
207 * This routine must be executed under the PM domain's lock.
208 */
209static bool default_power_down_ok(struct dev_pm_domain *pd)
210{
211 struct generic_pm_domain *genpd = pd_to_genpd(pd);
212 struct gpd_link *link;
213
214 if (!genpd->max_off_time_changed) {
215 genpd->state_idx = genpd->cached_power_down_state_idx;
216 return genpd->cached_power_down_ok;
217 }
218
219 /*
220 * We have to invalidate the cached results for the masters, so
221 * use the observation that default_power_down_ok() is not
222 * going to be called for any master until this instance
223 * returns.
224 */
225 list_for_each_entry(link, &genpd->slave_links, slave_node)
226 link->master->max_off_time_changed = true;
227
228 genpd->max_off_time_ns = -1;
229 genpd->max_off_time_changed = false;
230 genpd->cached_power_down_ok = true;
231 genpd->state_idx = genpd->state_count - 1;
232
233 /* Find a state to power down to, starting from the deepest. */
234 while (!__default_power_down_ok(pd, genpd->state_idx)) {
235 if (genpd->state_idx == 0) {
236 genpd->cached_power_down_ok = false;
237 break;
238 }
239 genpd->state_idx--;
240 }
241
242 genpd->cached_power_down_state_idx = genpd->state_idx;
243 return genpd->cached_power_down_ok;
244}
245
246static bool always_on_power_down_ok(struct dev_pm_domain *domain)
247{
248 return false;
249}
250
251#ifdef CONFIG_CPU_IDLE
252static bool cpu_power_down_ok(struct dev_pm_domain *pd)
253{
254 struct generic_pm_domain *genpd = pd_to_genpd(pd);
255 struct cpuidle_device *dev;
256 ktime_t domain_wakeup, next_hrtimer;
257 s64 idle_duration_ns;
258 int cpu, i;
259
260 /* Validate dev PM QoS constraints. */
261 if (!default_power_down_ok(pd))
262 return false;
263
264 if (!(genpd->flags & GENPD_FLAG_CPU_DOMAIN))
265 return true;
266
267 /*
268 * Find the next wakeup for any of the online CPUs within the PM domain
269 * and its subdomains. Note, we only need the genpd->cpus, as it already
270 * contains a mask of all CPUs from subdomains.
271 */
272 domain_wakeup = ktime_set(KTIME_SEC_MAX, 0);
273 for_each_cpu_and(cpu, genpd->cpus, cpu_online_mask) {
274 dev = per_cpu(cpuidle_devices, cpu);
275 if (dev) {
276 next_hrtimer = READ_ONCE(dev->next_hrtimer);
277 if (ktime_before(next_hrtimer, domain_wakeup))
278 domain_wakeup = next_hrtimer;
279 }
280 }
281
282 /* The minimum idle duration is from now - until the next wakeup. */
283 idle_duration_ns = ktime_to_ns(ktime_sub(domain_wakeup, ktime_get()));
284 if (idle_duration_ns <= 0)
285 return false;
286
287 /*
288 * Find the deepest idle state that has its residency value satisfied
289 * and by also taking into account the power off latency for the state.
290 * Start at the state picked by the dev PM QoS constraint validation.
291 */
292 i = genpd->state_idx;
293 do {
294 if (idle_duration_ns >= (genpd->states[i].residency_ns +
295 genpd->states[i].power_off_latency_ns)) {
296 genpd->state_idx = i;
297 return true;
298 }
299 } while (--i >= 0);
300
301 return false;
302}
303
304struct dev_power_governor pm_domain_cpu_gov = {
305 .suspend_ok = default_suspend_ok,
306 .power_down_ok = cpu_power_down_ok,
307};
308#endif
309
310struct dev_power_governor simple_qos_governor = {
311 .suspend_ok = default_suspend_ok,
312 .power_down_ok = default_power_down_ok,
313};
314
315/**
316 * pm_genpd_gov_always_on - A governor implementing an always-on policy
317 */
318struct dev_power_governor pm_domain_always_on_gov = {
319 .power_down_ok = always_on_power_down_ok,
320 .suspend_ok = default_suspend_ok,
321};