xref: /openbmc/linux/drivers/acpi/device_pm.c (revision 4da722ca)
1 /*
2  * drivers/acpi/device_pm.c - ACPI device power management routines.
3  *
4  * Copyright (C) 2012, Intel Corp.
5  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
6  *
7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License version 2 as published
11  *  by the Free Software Foundation.
12  *
13  *  This program is distributed in the hope that it will be useful, but
14  *  WITHOUT ANY WARRANTY; without even the implied warranty of
15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16  *  General Public License for more details.
17  *
18  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
19  */
20 
21 #include <linux/acpi.h>
22 #include <linux/export.h>
23 #include <linux/mutex.h>
24 #include <linux/pm_qos.h>
25 #include <linux/pm_domain.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/suspend.h>
28 
29 #include "internal.h"
30 
31 #define _COMPONENT	ACPI_POWER_COMPONENT
32 ACPI_MODULE_NAME("device_pm");
33 
34 /**
35  * acpi_power_state_string - String representation of ACPI device power state.
36  * @state: ACPI device power state to return the string representation of.
37  */
38 const char *acpi_power_state_string(int state)
39 {
40 	switch (state) {
41 	case ACPI_STATE_D0:
42 		return "D0";
43 	case ACPI_STATE_D1:
44 		return "D1";
45 	case ACPI_STATE_D2:
46 		return "D2";
47 	case ACPI_STATE_D3_HOT:
48 		return "D3hot";
49 	case ACPI_STATE_D3_COLD:
50 		return "D3cold";
51 	default:
52 		return "(unknown)";
53 	}
54 }
55 
56 /**
57  * acpi_device_get_power - Get power state of an ACPI device.
58  * @device: Device to get the power state of.
59  * @state: Place to store the power state of the device.
60  *
61  * This function does not update the device's power.state field, but it may
62  * update its parent's power.state field (when the parent's power state is
63  * unknown and the device's power state turns out to be D0).
64  */
65 int acpi_device_get_power(struct acpi_device *device, int *state)
66 {
67 	int result = ACPI_STATE_UNKNOWN;
68 
69 	if (!device || !state)
70 		return -EINVAL;
71 
72 	if (!device->flags.power_manageable) {
73 		/* TBD: Non-recursive algorithm for walking up hierarchy. */
74 		*state = device->parent ?
75 			device->parent->power.state : ACPI_STATE_D0;
76 		goto out;
77 	}
78 
79 	/*
80 	 * Get the device's power state from power resources settings and _PSC,
81 	 * if available.
82 	 */
83 	if (device->power.flags.power_resources) {
84 		int error = acpi_power_get_inferred_state(device, &result);
85 		if (error)
86 			return error;
87 	}
88 	if (device->power.flags.explicit_get) {
89 		acpi_handle handle = device->handle;
90 		unsigned long long psc;
91 		acpi_status status;
92 
93 		status = acpi_evaluate_integer(handle, "_PSC", NULL, &psc);
94 		if (ACPI_FAILURE(status))
95 			return -ENODEV;
96 
97 		/*
98 		 * The power resources settings may indicate a power state
99 		 * shallower than the actual power state of the device, because
100 		 * the same power resources may be referenced by other devices.
101 		 *
102 		 * For systems predating ACPI 4.0 we assume that D3hot is the
103 		 * deepest state that can be supported.
104 		 */
105 		if (psc > result && psc < ACPI_STATE_D3_COLD)
106 			result = psc;
107 		else if (result == ACPI_STATE_UNKNOWN)
108 			result = psc > ACPI_STATE_D2 ? ACPI_STATE_D3_HOT : psc;
109 	}
110 
111 	/*
112 	 * If we were unsure about the device parent's power state up to this
113 	 * point, the fact that the device is in D0 implies that the parent has
114 	 * to be in D0 too, except if ignore_parent is set.
115 	 */
116 	if (!device->power.flags.ignore_parent && device->parent
117 	    && device->parent->power.state == ACPI_STATE_UNKNOWN
118 	    && result == ACPI_STATE_D0)
119 		device->parent->power.state = ACPI_STATE_D0;
120 
121 	*state = result;
122 
123  out:
124 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] power state is %s\n",
125 			  device->pnp.bus_id, acpi_power_state_string(*state)));
126 
127 	return 0;
128 }
129 
130 static int acpi_dev_pm_explicit_set(struct acpi_device *adev, int state)
131 {
132 	if (adev->power.states[state].flags.explicit_set) {
133 		char method[5] = { '_', 'P', 'S', '0' + state, '\0' };
134 		acpi_status status;
135 
136 		status = acpi_evaluate_object(adev->handle, method, NULL, NULL);
137 		if (ACPI_FAILURE(status))
138 			return -ENODEV;
139 	}
140 	return 0;
141 }
142 
143 /**
144  * acpi_device_set_power - Set power state of an ACPI device.
145  * @device: Device to set the power state of.
146  * @state: New power state to set.
147  *
148  * Callers must ensure that the device is power manageable before using this
149  * function.
150  */
151 int acpi_device_set_power(struct acpi_device *device, int state)
152 {
153 	int target_state = state;
154 	int result = 0;
155 
156 	if (!device || !device->flags.power_manageable
157 	    || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
158 		return -EINVAL;
159 
160 	/* Make sure this is a valid target state */
161 
162 	if (state == device->power.state) {
163 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Device [%s] already in %s\n",
164 				  device->pnp.bus_id,
165 				  acpi_power_state_string(state)));
166 		return 0;
167 	}
168 
169 	if (state == ACPI_STATE_D3_COLD) {
170 		/*
171 		 * For transitions to D3cold we need to execute _PS3 and then
172 		 * possibly drop references to the power resources in use.
173 		 */
174 		state = ACPI_STATE_D3_HOT;
175 		/* If _PR3 is not available, use D3hot as the target state. */
176 		if (!device->power.states[ACPI_STATE_D3_COLD].flags.valid)
177 			target_state = state;
178 	} else if (!device->power.states[state].flags.valid) {
179 		dev_warn(&device->dev, "Power state %s not supported\n",
180 			 acpi_power_state_string(state));
181 		return -ENODEV;
182 	}
183 
184 	if (!device->power.flags.ignore_parent &&
185 	    device->parent && (state < device->parent->power.state)) {
186 		dev_warn(&device->dev,
187 			 "Cannot transition to power state %s for parent in %s\n",
188 			 acpi_power_state_string(state),
189 			 acpi_power_state_string(device->parent->power.state));
190 		return -ENODEV;
191 	}
192 
193 	/*
194 	 * Transition Power
195 	 * ----------------
196 	 * In accordance with ACPI 6, _PSx is executed before manipulating power
197 	 * resources, unless the target state is D0, in which case _PS0 is
198 	 * supposed to be executed after turning the power resources on.
199 	 */
200 	if (state > ACPI_STATE_D0) {
201 		/*
202 		 * According to ACPI 6, devices cannot go from lower-power
203 		 * (deeper) states to higher-power (shallower) states.
204 		 */
205 		if (state < device->power.state) {
206 			dev_warn(&device->dev, "Cannot transition from %s to %s\n",
207 				 acpi_power_state_string(device->power.state),
208 				 acpi_power_state_string(state));
209 			return -ENODEV;
210 		}
211 
212 		result = acpi_dev_pm_explicit_set(device, state);
213 		if (result)
214 			goto end;
215 
216 		if (device->power.flags.power_resources)
217 			result = acpi_power_transition(device, target_state);
218 	} else {
219 		if (device->power.flags.power_resources) {
220 			result = acpi_power_transition(device, ACPI_STATE_D0);
221 			if (result)
222 				goto end;
223 		}
224 		result = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
225 	}
226 
227  end:
228 	if (result) {
229 		dev_warn(&device->dev, "Failed to change power state to %s\n",
230 			 acpi_power_state_string(state));
231 	} else {
232 		device->power.state = target_state;
233 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
234 				  "Device [%s] transitioned to %s\n",
235 				  device->pnp.bus_id,
236 				  acpi_power_state_string(state)));
237 	}
238 
239 	return result;
240 }
241 EXPORT_SYMBOL(acpi_device_set_power);
242 
243 int acpi_bus_set_power(acpi_handle handle, int state)
244 {
245 	struct acpi_device *device;
246 	int result;
247 
248 	result = acpi_bus_get_device(handle, &device);
249 	if (result)
250 		return result;
251 
252 	return acpi_device_set_power(device, state);
253 }
254 EXPORT_SYMBOL(acpi_bus_set_power);
255 
256 int acpi_bus_init_power(struct acpi_device *device)
257 {
258 	int state;
259 	int result;
260 
261 	if (!device)
262 		return -EINVAL;
263 
264 	device->power.state = ACPI_STATE_UNKNOWN;
265 	if (!acpi_device_is_present(device)) {
266 		device->flags.initialized = false;
267 		return -ENXIO;
268 	}
269 
270 	result = acpi_device_get_power(device, &state);
271 	if (result)
272 		return result;
273 
274 	if (state < ACPI_STATE_D3_COLD && device->power.flags.power_resources) {
275 		/* Reference count the power resources. */
276 		result = acpi_power_on_resources(device, state);
277 		if (result)
278 			return result;
279 
280 		if (state == ACPI_STATE_D0) {
281 			/*
282 			 * If _PSC is not present and the state inferred from
283 			 * power resources appears to be D0, it still may be
284 			 * necessary to execute _PS0 at this point, because
285 			 * another device using the same power resources may
286 			 * have been put into D0 previously and that's why we
287 			 * see D0 here.
288 			 */
289 			result = acpi_dev_pm_explicit_set(device, state);
290 			if (result)
291 				return result;
292 		}
293 	} else if (state == ACPI_STATE_UNKNOWN) {
294 		/*
295 		 * No power resources and missing _PSC?  Cross fingers and make
296 		 * it D0 in hope that this is what the BIOS put the device into.
297 		 * [We tried to force D0 here by executing _PS0, but that broke
298 		 * Toshiba P870-303 in a nasty way.]
299 		 */
300 		state = ACPI_STATE_D0;
301 	}
302 	device->power.state = state;
303 	return 0;
304 }
305 
306 /**
307  * acpi_device_fix_up_power - Force device with missing _PSC into D0.
308  * @device: Device object whose power state is to be fixed up.
309  *
310  * Devices without power resources and _PSC, but having _PS0 and _PS3 defined,
311  * are assumed to be put into D0 by the BIOS.  However, in some cases that may
312  * not be the case and this function should be used then.
313  */
314 int acpi_device_fix_up_power(struct acpi_device *device)
315 {
316 	int ret = 0;
317 
318 	if (!device->power.flags.power_resources
319 	    && !device->power.flags.explicit_get
320 	    && device->power.state == ACPI_STATE_D0)
321 		ret = acpi_dev_pm_explicit_set(device, ACPI_STATE_D0);
322 
323 	return ret;
324 }
325 EXPORT_SYMBOL_GPL(acpi_device_fix_up_power);
326 
327 int acpi_device_update_power(struct acpi_device *device, int *state_p)
328 {
329 	int state;
330 	int result;
331 
332 	if (device->power.state == ACPI_STATE_UNKNOWN) {
333 		result = acpi_bus_init_power(device);
334 		if (!result && state_p)
335 			*state_p = device->power.state;
336 
337 		return result;
338 	}
339 
340 	result = acpi_device_get_power(device, &state);
341 	if (result)
342 		return result;
343 
344 	if (state == ACPI_STATE_UNKNOWN) {
345 		state = ACPI_STATE_D0;
346 		result = acpi_device_set_power(device, state);
347 		if (result)
348 			return result;
349 	} else {
350 		if (device->power.flags.power_resources) {
351 			/*
352 			 * We don't need to really switch the state, bu we need
353 			 * to update the power resources' reference counters.
354 			 */
355 			result = acpi_power_transition(device, state);
356 			if (result)
357 				return result;
358 		}
359 		device->power.state = state;
360 	}
361 	if (state_p)
362 		*state_p = state;
363 
364 	return 0;
365 }
366 EXPORT_SYMBOL_GPL(acpi_device_update_power);
367 
368 int acpi_bus_update_power(acpi_handle handle, int *state_p)
369 {
370 	struct acpi_device *device;
371 	int result;
372 
373 	result = acpi_bus_get_device(handle, &device);
374 	return result ? result : acpi_device_update_power(device, state_p);
375 }
376 EXPORT_SYMBOL_GPL(acpi_bus_update_power);
377 
378 bool acpi_bus_power_manageable(acpi_handle handle)
379 {
380 	struct acpi_device *device;
381 	int result;
382 
383 	result = acpi_bus_get_device(handle, &device);
384 	return result ? false : device->flags.power_manageable;
385 }
386 EXPORT_SYMBOL(acpi_bus_power_manageable);
387 
388 #ifdef CONFIG_PM
389 static DEFINE_MUTEX(acpi_pm_notifier_lock);
390 
391 void acpi_pm_wakeup_event(struct device *dev)
392 {
393 	pm_wakeup_dev_event(dev, 0, acpi_s2idle_wakeup());
394 }
395 EXPORT_SYMBOL_GPL(acpi_pm_wakeup_event);
396 
397 static void acpi_pm_notify_handler(acpi_handle handle, u32 val, void *not_used)
398 {
399 	struct acpi_device *adev;
400 
401 	if (val != ACPI_NOTIFY_DEVICE_WAKE)
402 		return;
403 
404 	adev = acpi_bus_get_acpi_device(handle);
405 	if (!adev)
406 		return;
407 
408 	mutex_lock(&acpi_pm_notifier_lock);
409 
410 	if (adev->wakeup.flags.notifier_present) {
411 		pm_wakeup_ws_event(adev->wakeup.ws, 0, acpi_s2idle_wakeup());
412 		if (adev->wakeup.context.func)
413 			adev->wakeup.context.func(&adev->wakeup.context);
414 	}
415 
416 	mutex_unlock(&acpi_pm_notifier_lock);
417 
418 	acpi_bus_put_acpi_device(adev);
419 }
420 
421 /**
422  * acpi_add_pm_notifier - Register PM notify handler for given ACPI device.
423  * @adev: ACPI device to add the notify handler for.
424  * @dev: Device to generate a wakeup event for while handling the notification.
425  * @func: Work function to execute when handling the notification.
426  *
427  * NOTE: @adev need not be a run-wake or wakeup device to be a valid source of
428  * PM wakeup events.  For example, wakeup events may be generated for bridges
429  * if one of the devices below the bridge is signaling wakeup, even if the
430  * bridge itself doesn't have a wakeup GPE associated with it.
431  */
432 acpi_status acpi_add_pm_notifier(struct acpi_device *adev, struct device *dev,
433 			void (*func)(struct acpi_device_wakeup_context *context))
434 {
435 	acpi_status status = AE_ALREADY_EXISTS;
436 
437 	if (!dev && !func)
438 		return AE_BAD_PARAMETER;
439 
440 	mutex_lock(&acpi_pm_notifier_lock);
441 
442 	if (adev->wakeup.flags.notifier_present)
443 		goto out;
444 
445 	adev->wakeup.ws = wakeup_source_register(dev_name(&adev->dev));
446 	adev->wakeup.context.dev = dev;
447 	adev->wakeup.context.func = func;
448 
449 	status = acpi_install_notify_handler(adev->handle, ACPI_SYSTEM_NOTIFY,
450 					     acpi_pm_notify_handler, NULL);
451 	if (ACPI_FAILURE(status))
452 		goto out;
453 
454 	adev->wakeup.flags.notifier_present = true;
455 
456  out:
457 	mutex_unlock(&acpi_pm_notifier_lock);
458 	return status;
459 }
460 
461 /**
462  * acpi_remove_pm_notifier - Unregister PM notifier from given ACPI device.
463  * @adev: ACPI device to remove the notifier from.
464  */
465 acpi_status acpi_remove_pm_notifier(struct acpi_device *adev)
466 {
467 	acpi_status status = AE_BAD_PARAMETER;
468 
469 	mutex_lock(&acpi_pm_notifier_lock);
470 
471 	if (!adev->wakeup.flags.notifier_present)
472 		goto out;
473 
474 	status = acpi_remove_notify_handler(adev->handle,
475 					    ACPI_SYSTEM_NOTIFY,
476 					    acpi_pm_notify_handler);
477 	if (ACPI_FAILURE(status))
478 		goto out;
479 
480 	adev->wakeup.context.func = NULL;
481 	adev->wakeup.context.dev = NULL;
482 	wakeup_source_unregister(adev->wakeup.ws);
483 
484 	adev->wakeup.flags.notifier_present = false;
485 
486  out:
487 	mutex_unlock(&acpi_pm_notifier_lock);
488 	return status;
489 }
490 
491 bool acpi_bus_can_wakeup(acpi_handle handle)
492 {
493 	struct acpi_device *device;
494 	int result;
495 
496 	result = acpi_bus_get_device(handle, &device);
497 	return result ? false : device->wakeup.flags.valid;
498 }
499 EXPORT_SYMBOL(acpi_bus_can_wakeup);
500 
501 bool acpi_pm_device_can_wakeup(struct device *dev)
502 {
503 	struct acpi_device *adev = ACPI_COMPANION(dev);
504 
505 	return adev ? acpi_device_can_wakeup(adev) : false;
506 }
507 
508 /**
509  * acpi_dev_pm_get_state - Get preferred power state of ACPI device.
510  * @dev: Device whose preferred target power state to return.
511  * @adev: ACPI device node corresponding to @dev.
512  * @target_state: System state to match the resultant device state.
513  * @d_min_p: Location to store the highest power state available to the device.
514  * @d_max_p: Location to store the lowest power state available to the device.
515  *
516  * Find the lowest power (highest number) and highest power (lowest number) ACPI
517  * device power states that the device can be in while the system is in the
518  * state represented by @target_state.  Store the integer numbers representing
519  * those stats in the memory locations pointed to by @d_max_p and @d_min_p,
520  * respectively.
521  *
522  * Callers must ensure that @dev and @adev are valid pointers and that @adev
523  * actually corresponds to @dev before using this function.
524  *
525  * Returns 0 on success or -ENODATA when one of the ACPI methods fails or
526  * returns a value that doesn't make sense.  The memory locations pointed to by
527  * @d_max_p and @d_min_p are only modified on success.
528  */
529 static int acpi_dev_pm_get_state(struct device *dev, struct acpi_device *adev,
530 				 u32 target_state, int *d_min_p, int *d_max_p)
531 {
532 	char method[] = { '_', 'S', '0' + target_state, 'D', '\0' };
533 	acpi_handle handle = adev->handle;
534 	unsigned long long ret;
535 	int d_min, d_max;
536 	bool wakeup = false;
537 	acpi_status status;
538 
539 	/*
540 	 * If the system state is S0, the lowest power state the device can be
541 	 * in is D3cold, unless the device has _S0W and is supposed to signal
542 	 * wakeup, in which case the return value of _S0W has to be used as the
543 	 * lowest power state available to the device.
544 	 */
545 	d_min = ACPI_STATE_D0;
546 	d_max = ACPI_STATE_D3_COLD;
547 
548 	/*
549 	 * If present, _SxD methods return the minimum D-state (highest power
550 	 * state) we can use for the corresponding S-states.  Otherwise, the
551 	 * minimum D-state is D0 (ACPI 3.x).
552 	 */
553 	if (target_state > ACPI_STATE_S0) {
554 		/*
555 		 * We rely on acpi_evaluate_integer() not clobbering the integer
556 		 * provided if AE_NOT_FOUND is returned.
557 		 */
558 		ret = d_min;
559 		status = acpi_evaluate_integer(handle, method, NULL, &ret);
560 		if ((ACPI_FAILURE(status) && status != AE_NOT_FOUND)
561 		    || ret > ACPI_STATE_D3_COLD)
562 			return -ENODATA;
563 
564 		/*
565 		 * We need to handle legacy systems where D3hot and D3cold are
566 		 * the same and 3 is returned in both cases, so fall back to
567 		 * D3cold if D3hot is not a valid state.
568 		 */
569 		if (!adev->power.states[ret].flags.valid) {
570 			if (ret == ACPI_STATE_D3_HOT)
571 				ret = ACPI_STATE_D3_COLD;
572 			else
573 				return -ENODATA;
574 		}
575 		d_min = ret;
576 		wakeup = device_may_wakeup(dev) && adev->wakeup.flags.valid
577 			&& adev->wakeup.sleep_state >= target_state;
578 	} else if (dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) !=
579 			PM_QOS_FLAGS_NONE) {
580 		wakeup = adev->wakeup.flags.valid;
581 	}
582 
583 	/*
584 	 * If _PRW says we can wake up the system from the target sleep state,
585 	 * the D-state returned by _SxD is sufficient for that (we assume a
586 	 * wakeup-aware driver if wake is set).  Still, if _SxW exists
587 	 * (ACPI 3.x), it should return the maximum (lowest power) D-state that
588 	 * can wake the system.  _S0W may be valid, too.
589 	 */
590 	if (wakeup) {
591 		method[3] = 'W';
592 		status = acpi_evaluate_integer(handle, method, NULL, &ret);
593 		if (status == AE_NOT_FOUND) {
594 			if (target_state > ACPI_STATE_S0)
595 				d_max = d_min;
596 		} else if (ACPI_SUCCESS(status) && ret <= ACPI_STATE_D3_COLD) {
597 			/* Fall back to D3cold if ret is not a valid state. */
598 			if (!adev->power.states[ret].flags.valid)
599 				ret = ACPI_STATE_D3_COLD;
600 
601 			d_max = ret > d_min ? ret : d_min;
602 		} else {
603 			return -ENODATA;
604 		}
605 	}
606 
607 	if (d_min_p)
608 		*d_min_p = d_min;
609 
610 	if (d_max_p)
611 		*d_max_p = d_max;
612 
613 	return 0;
614 }
615 
616 /**
617  * acpi_pm_device_sleep_state - Get preferred power state of ACPI device.
618  * @dev: Device whose preferred target power state to return.
619  * @d_min_p: Location to store the upper limit of the allowed states range.
620  * @d_max_in: Deepest low-power state to take into consideration.
621  * Return value: Preferred power state of the device on success, -ENODEV
622  * if there's no 'struct acpi_device' for @dev, -EINVAL if @d_max_in is
623  * incorrect, or -ENODATA on ACPI method failure.
624  *
625  * The caller must ensure that @dev is valid before using this function.
626  */
627 int acpi_pm_device_sleep_state(struct device *dev, int *d_min_p, int d_max_in)
628 {
629 	struct acpi_device *adev;
630 	int ret, d_min, d_max;
631 
632 	if (d_max_in < ACPI_STATE_D0 || d_max_in > ACPI_STATE_D3_COLD)
633 		return -EINVAL;
634 
635 	if (d_max_in > ACPI_STATE_D2) {
636 		enum pm_qos_flags_status stat;
637 
638 		stat = dev_pm_qos_flags(dev, PM_QOS_FLAG_NO_POWER_OFF);
639 		if (stat == PM_QOS_FLAGS_ALL)
640 			d_max_in = ACPI_STATE_D2;
641 	}
642 
643 	adev = ACPI_COMPANION(dev);
644 	if (!adev) {
645 		dev_dbg(dev, "ACPI companion missing in %s!\n", __func__);
646 		return -ENODEV;
647 	}
648 
649 	ret = acpi_dev_pm_get_state(dev, adev, acpi_target_system_state(),
650 				    &d_min, &d_max);
651 	if (ret)
652 		return ret;
653 
654 	if (d_max_in < d_min)
655 		return -EINVAL;
656 
657 	if (d_max > d_max_in) {
658 		for (d_max = d_max_in; d_max > d_min; d_max--) {
659 			if (adev->power.states[d_max].flags.valid)
660 				break;
661 		}
662 	}
663 
664 	if (d_min_p)
665 		*d_min_p = d_min;
666 
667 	return d_max;
668 }
669 EXPORT_SYMBOL(acpi_pm_device_sleep_state);
670 
671 /**
672  * acpi_pm_notify_work_func - ACPI devices wakeup notification work function.
673  * @context: Device wakeup context.
674  */
675 static void acpi_pm_notify_work_func(struct acpi_device_wakeup_context *context)
676 {
677 	struct device *dev = context->dev;
678 
679 	if (dev) {
680 		pm_wakeup_event(dev, 0);
681 		pm_request_resume(dev);
682 	}
683 }
684 
685 /**
686  * acpi_device_wakeup - Enable/disable wakeup functionality for device.
687  * @adev: ACPI device to enable/disable wakeup functionality for.
688  * @target_state: State the system is transitioning into.
689  * @enable: Whether to enable or disable the wakeup functionality.
690  *
691  * Enable/disable the GPE associated with @adev so that it can generate
692  * wakeup signals for the device in response to external (remote) events and
693  * enable/disable device wakeup power.
694  *
695  * Callers must ensure that @adev is a valid ACPI device node before executing
696  * this function.
697  */
698 static int acpi_device_wakeup(struct acpi_device *adev, u32 target_state,
699 			      bool enable)
700 {
701 	struct acpi_device_wakeup *wakeup = &adev->wakeup;
702 
703 	if (enable) {
704 		acpi_status res;
705 		int error;
706 
707 		if (adev->wakeup.flags.enabled)
708 			return 0;
709 
710 		error = acpi_enable_wakeup_device_power(adev, target_state);
711 		if (error)
712 			return error;
713 
714 		res = acpi_enable_gpe(wakeup->gpe_device, wakeup->gpe_number);
715 		if (ACPI_FAILURE(res)) {
716 			acpi_disable_wakeup_device_power(adev);
717 			return -EIO;
718 		}
719 		adev->wakeup.flags.enabled = 1;
720 	} else if (adev->wakeup.flags.enabled) {
721 		acpi_disable_gpe(wakeup->gpe_device, wakeup->gpe_number);
722 		acpi_disable_wakeup_device_power(adev);
723 		adev->wakeup.flags.enabled = 0;
724 	}
725 	return 0;
726 }
727 
728 /**
729  * acpi_pm_set_device_wakeup - Enable/disable remote wakeup for given device.
730  * @dev: Device to enable/disable to generate wakeup events.
731  * @enable: Whether to enable or disable the wakeup functionality.
732  */
733 int acpi_pm_set_device_wakeup(struct device *dev, bool enable)
734 {
735 	struct acpi_device *adev;
736 	int error;
737 
738 	adev = ACPI_COMPANION(dev);
739 	if (!adev) {
740 		dev_dbg(dev, "ACPI companion missing in %s!\n", __func__);
741 		return -ENODEV;
742 	}
743 
744 	if (!acpi_device_can_wakeup(adev))
745 		return -EINVAL;
746 
747 	error = acpi_device_wakeup(adev, acpi_target_system_state(), enable);
748 	if (!error)
749 		dev_dbg(dev, "Wakeup %s by ACPI\n", enable ? "enabled" : "disabled");
750 
751 	return error;
752 }
753 EXPORT_SYMBOL(acpi_pm_set_device_wakeup);
754 
755 /**
756  * acpi_dev_pm_low_power - Put ACPI device into a low-power state.
757  * @dev: Device to put into a low-power state.
758  * @adev: ACPI device node corresponding to @dev.
759  * @system_state: System state to choose the device state for.
760  */
761 static int acpi_dev_pm_low_power(struct device *dev, struct acpi_device *adev,
762 				 u32 system_state)
763 {
764 	int ret, state;
765 
766 	if (!acpi_device_power_manageable(adev))
767 		return 0;
768 
769 	ret = acpi_dev_pm_get_state(dev, adev, system_state, NULL, &state);
770 	return ret ? ret : acpi_device_set_power(adev, state);
771 }
772 
773 /**
774  * acpi_dev_pm_full_power - Put ACPI device into the full-power state.
775  * @adev: ACPI device node to put into the full-power state.
776  */
777 static int acpi_dev_pm_full_power(struct acpi_device *adev)
778 {
779 	return acpi_device_power_manageable(adev) ?
780 		acpi_device_set_power(adev, ACPI_STATE_D0) : 0;
781 }
782 
783 /**
784  * acpi_dev_runtime_suspend - Put device into a low-power state using ACPI.
785  * @dev: Device to put into a low-power state.
786  *
787  * Put the given device into a runtime low-power state using the standard ACPI
788  * mechanism.  Set up remote wakeup if desired, choose the state to put the
789  * device into (this checks if remote wakeup is expected to work too), and set
790  * the power state of the device.
791  */
792 int acpi_dev_runtime_suspend(struct device *dev)
793 {
794 	struct acpi_device *adev = ACPI_COMPANION(dev);
795 	bool remote_wakeup;
796 	int error;
797 
798 	if (!adev)
799 		return 0;
800 
801 	remote_wakeup = dev_pm_qos_flags(dev, PM_QOS_FLAG_REMOTE_WAKEUP) >
802 				PM_QOS_FLAGS_NONE;
803 	error = acpi_device_wakeup(adev, ACPI_STATE_S0, remote_wakeup);
804 	if (remote_wakeup && error)
805 		return -EAGAIN;
806 
807 	error = acpi_dev_pm_low_power(dev, adev, ACPI_STATE_S0);
808 	if (error)
809 		acpi_device_wakeup(adev, ACPI_STATE_S0, false);
810 
811 	return error;
812 }
813 EXPORT_SYMBOL_GPL(acpi_dev_runtime_suspend);
814 
815 /**
816  * acpi_dev_runtime_resume - Put device into the full-power state using ACPI.
817  * @dev: Device to put into the full-power state.
818  *
819  * Put the given device into the full-power state using the standard ACPI
820  * mechanism at run time.  Set the power state of the device to ACPI D0 and
821  * disable remote wakeup.
822  */
823 int acpi_dev_runtime_resume(struct device *dev)
824 {
825 	struct acpi_device *adev = ACPI_COMPANION(dev);
826 	int error;
827 
828 	if (!adev)
829 		return 0;
830 
831 	error = acpi_dev_pm_full_power(adev);
832 	acpi_device_wakeup(adev, ACPI_STATE_S0, false);
833 	return error;
834 }
835 EXPORT_SYMBOL_GPL(acpi_dev_runtime_resume);
836 
837 /**
838  * acpi_subsys_runtime_suspend - Suspend device using ACPI.
839  * @dev: Device to suspend.
840  *
841  * Carry out the generic runtime suspend procedure for @dev and use ACPI to put
842  * it into a runtime low-power state.
843  */
844 int acpi_subsys_runtime_suspend(struct device *dev)
845 {
846 	int ret = pm_generic_runtime_suspend(dev);
847 	return ret ? ret : acpi_dev_runtime_suspend(dev);
848 }
849 EXPORT_SYMBOL_GPL(acpi_subsys_runtime_suspend);
850 
851 /**
852  * acpi_subsys_runtime_resume - Resume device using ACPI.
853  * @dev: Device to Resume.
854  *
855  * Use ACPI to put the given device into the full-power state and carry out the
856  * generic runtime resume procedure for it.
857  */
858 int acpi_subsys_runtime_resume(struct device *dev)
859 {
860 	int ret = acpi_dev_runtime_resume(dev);
861 	return ret ? ret : pm_generic_runtime_resume(dev);
862 }
863 EXPORT_SYMBOL_GPL(acpi_subsys_runtime_resume);
864 
865 #ifdef CONFIG_PM_SLEEP
866 /**
867  * acpi_dev_suspend_late - Put device into a low-power state using ACPI.
868  * @dev: Device to put into a low-power state.
869  *
870  * Put the given device into a low-power state during system transition to a
871  * sleep state using the standard ACPI mechanism.  Set up system wakeup if
872  * desired, choose the state to put the device into (this checks if system
873  * wakeup is expected to work too), and set the power state of the device.
874  */
875 int acpi_dev_suspend_late(struct device *dev)
876 {
877 	struct acpi_device *adev = ACPI_COMPANION(dev);
878 	u32 target_state;
879 	bool wakeup;
880 	int error;
881 
882 	if (!adev)
883 		return 0;
884 
885 	target_state = acpi_target_system_state();
886 	wakeup = device_may_wakeup(dev) && acpi_device_can_wakeup(adev);
887 	error = acpi_device_wakeup(adev, target_state, wakeup);
888 	if (wakeup && error)
889 		return error;
890 
891 	error = acpi_dev_pm_low_power(dev, adev, target_state);
892 	if (error)
893 		acpi_device_wakeup(adev, ACPI_STATE_UNKNOWN, false);
894 
895 	return error;
896 }
897 EXPORT_SYMBOL_GPL(acpi_dev_suspend_late);
898 
899 /**
900  * acpi_dev_resume_early - Put device into the full-power state using ACPI.
901  * @dev: Device to put into the full-power state.
902  *
903  * Put the given device into the full-power state using the standard ACPI
904  * mechanism during system transition to the working state.  Set the power
905  * state of the device to ACPI D0 and disable remote wakeup.
906  */
907 int acpi_dev_resume_early(struct device *dev)
908 {
909 	struct acpi_device *adev = ACPI_COMPANION(dev);
910 	int error;
911 
912 	if (!adev)
913 		return 0;
914 
915 	error = acpi_dev_pm_full_power(adev);
916 	acpi_device_wakeup(adev, ACPI_STATE_UNKNOWN, false);
917 	return error;
918 }
919 EXPORT_SYMBOL_GPL(acpi_dev_resume_early);
920 
921 /**
922  * acpi_subsys_prepare - Prepare device for system transition to a sleep state.
923  * @dev: Device to prepare.
924  */
925 int acpi_subsys_prepare(struct device *dev)
926 {
927 	struct acpi_device *adev = ACPI_COMPANION(dev);
928 	u32 sys_target;
929 	int ret, state;
930 
931 	ret = pm_generic_prepare(dev);
932 	if (ret < 0)
933 		return ret;
934 
935 	if (!adev || !pm_runtime_suspended(dev)
936 	    || device_may_wakeup(dev) != !!adev->wakeup.prepare_count)
937 		return 0;
938 
939 	sys_target = acpi_target_system_state();
940 	if (sys_target == ACPI_STATE_S0)
941 		return 1;
942 
943 	if (adev->power.flags.dsw_present)
944 		return 0;
945 
946 	ret = acpi_dev_pm_get_state(dev, adev, sys_target, NULL, &state);
947 	return !ret && state == adev->power.state;
948 }
949 EXPORT_SYMBOL_GPL(acpi_subsys_prepare);
950 
951 /**
952  * acpi_subsys_suspend - Run the device driver's suspend callback.
953  * @dev: Device to handle.
954  *
955  * Follow PCI and resume devices suspended at run time before running their
956  * system suspend callbacks.
957  */
958 int acpi_subsys_suspend(struct device *dev)
959 {
960 	pm_runtime_resume(dev);
961 	return pm_generic_suspend(dev);
962 }
963 EXPORT_SYMBOL_GPL(acpi_subsys_suspend);
964 
965 /**
966  * acpi_subsys_suspend_late - Suspend device using ACPI.
967  * @dev: Device to suspend.
968  *
969  * Carry out the generic late suspend procedure for @dev and use ACPI to put
970  * it into a low-power state during system transition into a sleep state.
971  */
972 int acpi_subsys_suspend_late(struct device *dev)
973 {
974 	int ret = pm_generic_suspend_late(dev);
975 	return ret ? ret : acpi_dev_suspend_late(dev);
976 }
977 EXPORT_SYMBOL_GPL(acpi_subsys_suspend_late);
978 
979 /**
980  * acpi_subsys_resume_early - Resume device using ACPI.
981  * @dev: Device to Resume.
982  *
983  * Use ACPI to put the given device into the full-power state and carry out the
984  * generic early resume procedure for it during system transition into the
985  * working state.
986  */
987 int acpi_subsys_resume_early(struct device *dev)
988 {
989 	int ret = acpi_dev_resume_early(dev);
990 	return ret ? ret : pm_generic_resume_early(dev);
991 }
992 EXPORT_SYMBOL_GPL(acpi_subsys_resume_early);
993 
994 /**
995  * acpi_subsys_freeze - Run the device driver's freeze callback.
996  * @dev: Device to handle.
997  */
998 int acpi_subsys_freeze(struct device *dev)
999 {
1000 	/*
1001 	 * This used to be done in acpi_subsys_prepare() for all devices and
1002 	 * some drivers may depend on it, so do it here.  Ideally, however,
1003 	 * runtime-suspended devices should not be touched during freeze/thaw
1004 	 * transitions.
1005 	 */
1006 	pm_runtime_resume(dev);
1007 	return pm_generic_freeze(dev);
1008 }
1009 EXPORT_SYMBOL_GPL(acpi_subsys_freeze);
1010 
1011 #endif /* CONFIG_PM_SLEEP */
1012 
1013 static struct dev_pm_domain acpi_general_pm_domain = {
1014 	.ops = {
1015 		.runtime_suspend = acpi_subsys_runtime_suspend,
1016 		.runtime_resume = acpi_subsys_runtime_resume,
1017 #ifdef CONFIG_PM_SLEEP
1018 		.prepare = acpi_subsys_prepare,
1019 		.complete = pm_complete_with_resume_check,
1020 		.suspend = acpi_subsys_suspend,
1021 		.suspend_late = acpi_subsys_suspend_late,
1022 		.resume_early = acpi_subsys_resume_early,
1023 		.freeze = acpi_subsys_freeze,
1024 		.poweroff = acpi_subsys_suspend,
1025 		.poweroff_late = acpi_subsys_suspend_late,
1026 		.restore_early = acpi_subsys_resume_early,
1027 #endif
1028 	},
1029 };
1030 
1031 /**
1032  * acpi_dev_pm_detach - Remove ACPI power management from the device.
1033  * @dev: Device to take care of.
1034  * @power_off: Whether or not to try to remove power from the device.
1035  *
1036  * Remove the device from the general ACPI PM domain and remove its wakeup
1037  * notifier.  If @power_off is set, additionally remove power from the device if
1038  * possible.
1039  *
1040  * Callers must ensure proper synchronization of this function with power
1041  * management callbacks.
1042  */
1043 static void acpi_dev_pm_detach(struct device *dev, bool power_off)
1044 {
1045 	struct acpi_device *adev = ACPI_COMPANION(dev);
1046 
1047 	if (adev && dev->pm_domain == &acpi_general_pm_domain) {
1048 		dev_pm_domain_set(dev, NULL);
1049 		acpi_remove_pm_notifier(adev);
1050 		if (power_off) {
1051 			/*
1052 			 * If the device's PM QoS resume latency limit or flags
1053 			 * have been exposed to user space, they have to be
1054 			 * hidden at this point, so that they don't affect the
1055 			 * choice of the low-power state to put the device into.
1056 			 */
1057 			dev_pm_qos_hide_latency_limit(dev);
1058 			dev_pm_qos_hide_flags(dev);
1059 			acpi_device_wakeup(adev, ACPI_STATE_S0, false);
1060 			acpi_dev_pm_low_power(dev, adev, ACPI_STATE_S0);
1061 		}
1062 	}
1063 }
1064 
1065 /**
1066  * acpi_dev_pm_attach - Prepare device for ACPI power management.
1067  * @dev: Device to prepare.
1068  * @power_on: Whether or not to power on the device.
1069  *
1070  * If @dev has a valid ACPI handle that has a valid struct acpi_device object
1071  * attached to it, install a wakeup notification handler for the device and
1072  * add it to the general ACPI PM domain.  If @power_on is set, the device will
1073  * be put into the ACPI D0 state before the function returns.
1074  *
1075  * This assumes that the @dev's bus type uses generic power management callbacks
1076  * (or doesn't use any power management callbacks at all).
1077  *
1078  * Callers must ensure proper synchronization of this function with power
1079  * management callbacks.
1080  */
1081 int acpi_dev_pm_attach(struct device *dev, bool power_on)
1082 {
1083 	struct acpi_device *adev = ACPI_COMPANION(dev);
1084 
1085 	if (!adev)
1086 		return -ENODEV;
1087 
1088 	if (dev->pm_domain)
1089 		return -EEXIST;
1090 
1091 	/*
1092 	 * Only attach the power domain to the first device if the
1093 	 * companion is shared by multiple. This is to prevent doing power
1094 	 * management twice.
1095 	 */
1096 	if (!acpi_device_is_first_physical_node(adev, dev))
1097 		return -EBUSY;
1098 
1099 	acpi_add_pm_notifier(adev, dev, acpi_pm_notify_work_func);
1100 	dev_pm_domain_set(dev, &acpi_general_pm_domain);
1101 	if (power_on) {
1102 		acpi_dev_pm_full_power(adev);
1103 		acpi_device_wakeup(adev, ACPI_STATE_S0, false);
1104 	}
1105 
1106 	dev->pm_domain->detach = acpi_dev_pm_detach;
1107 	return 0;
1108 }
1109 EXPORT_SYMBOL_GPL(acpi_dev_pm_attach);
1110 #endif /* CONFIG_PM */
1111