xref: /linux/drivers/acpi/power.c (revision c0e297dc61f8d4453e07afbea1fa8d0e67cd4a34)
1 /*
2  *  acpi_power.c - ACPI Bus Power Management ($Revision: 39 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@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 as published by
11  *  the Free Software Foundation; either version 2 of the License, or (at
12  *  your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful, but
15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17  *  General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
22  *
23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
24  */
25 
26 /*
27  * ACPI power-managed devices may be controlled in two ways:
28  * 1. via "Device Specific (D-State) Control"
29  * 2. via "Power Resource Control".
30  * This module is used to manage devices relying on Power Resource Control.
31  *
32  * An ACPI "power resource object" describes a software controllable power
33  * plane, clock plane, or other resource used by a power managed device.
34  * A device may rely on multiple power resources, and a power resource
35  * may be shared by multiple devices.
36  */
37 
38 #include <linux/kernel.h>
39 #include <linux/module.h>
40 #include <linux/init.h>
41 #include <linux/types.h>
42 #include <linux/slab.h>
43 #include <linux/pm_runtime.h>
44 #include <linux/sysfs.h>
45 #include <linux/acpi.h>
46 #include "sleep.h"
47 #include "internal.h"
48 
49 #define _COMPONENT			ACPI_POWER_COMPONENT
50 ACPI_MODULE_NAME("power");
51 #define ACPI_POWER_CLASS		"power_resource"
52 #define ACPI_POWER_DEVICE_NAME		"Power Resource"
53 #define ACPI_POWER_FILE_INFO		"info"
54 #define ACPI_POWER_FILE_STATUS		"state"
55 #define ACPI_POWER_RESOURCE_STATE_OFF	0x00
56 #define ACPI_POWER_RESOURCE_STATE_ON	0x01
57 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
58 
59 struct acpi_power_resource {
60 	struct acpi_device device;
61 	struct list_head list_node;
62 	char *name;
63 	u32 system_level;
64 	u32 order;
65 	unsigned int ref_count;
66 	bool wakeup_enabled;
67 	struct mutex resource_lock;
68 };
69 
70 struct acpi_power_resource_entry {
71 	struct list_head node;
72 	struct acpi_power_resource *resource;
73 };
74 
75 static LIST_HEAD(acpi_power_resource_list);
76 static DEFINE_MUTEX(power_resource_list_lock);
77 
78 /* --------------------------------------------------------------------------
79                              Power Resource Management
80    -------------------------------------------------------------------------- */
81 
82 static inline
83 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
84 {
85 	return container_of(device, struct acpi_power_resource, device);
86 }
87 
88 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
89 {
90 	struct acpi_device *device;
91 
92 	if (acpi_bus_get_device(handle, &device))
93 		return NULL;
94 
95 	return to_power_resource(device);
96 }
97 
98 static int acpi_power_resources_list_add(acpi_handle handle,
99 					 struct list_head *list)
100 {
101 	struct acpi_power_resource *resource = acpi_power_get_context(handle);
102 	struct acpi_power_resource_entry *entry;
103 
104 	if (!resource || !list)
105 		return -EINVAL;
106 
107 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
108 	if (!entry)
109 		return -ENOMEM;
110 
111 	entry->resource = resource;
112 	if (!list_empty(list)) {
113 		struct acpi_power_resource_entry *e;
114 
115 		list_for_each_entry(e, list, node)
116 			if (e->resource->order > resource->order) {
117 				list_add_tail(&entry->node, &e->node);
118 				return 0;
119 			}
120 	}
121 	list_add_tail(&entry->node, list);
122 	return 0;
123 }
124 
125 void acpi_power_resources_list_free(struct list_head *list)
126 {
127 	struct acpi_power_resource_entry *entry, *e;
128 
129 	list_for_each_entry_safe(entry, e, list, node) {
130 		list_del(&entry->node);
131 		kfree(entry);
132 	}
133 }
134 
135 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
136 				 struct list_head *list)
137 {
138 	unsigned int i;
139 	int err = 0;
140 
141 	for (i = start; i < package->package.count; i++) {
142 		union acpi_object *element = &package->package.elements[i];
143 		acpi_handle rhandle;
144 
145 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
146 			err = -ENODATA;
147 			break;
148 		}
149 		rhandle = element->reference.handle;
150 		if (!rhandle) {
151 			err = -ENODEV;
152 			break;
153 		}
154 		err = acpi_add_power_resource(rhandle);
155 		if (err)
156 			break;
157 
158 		err = acpi_power_resources_list_add(rhandle, list);
159 		if (err)
160 			break;
161 	}
162 	if (err)
163 		acpi_power_resources_list_free(list);
164 
165 	return err;
166 }
167 
168 static int acpi_power_get_state(acpi_handle handle, int *state)
169 {
170 	acpi_status status = AE_OK;
171 	unsigned long long sta = 0;
172 	char node_name[5];
173 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
174 
175 
176 	if (!handle || !state)
177 		return -EINVAL;
178 
179 	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
180 	if (ACPI_FAILURE(status))
181 		return -ENODEV;
182 
183 	*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
184 			      ACPI_POWER_RESOURCE_STATE_OFF;
185 
186 	acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
187 
188 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
189 			  node_name,
190 				*state ? "on" : "off"));
191 
192 	return 0;
193 }
194 
195 static int acpi_power_get_list_state(struct list_head *list, int *state)
196 {
197 	struct acpi_power_resource_entry *entry;
198 	int cur_state;
199 
200 	if (!list || !state)
201 		return -EINVAL;
202 
203 	/* The state of the list is 'on' IFF all resources are 'on'. */
204 	list_for_each_entry(entry, list, node) {
205 		struct acpi_power_resource *resource = entry->resource;
206 		acpi_handle handle = resource->device.handle;
207 		int result;
208 
209 		mutex_lock(&resource->resource_lock);
210 		result = acpi_power_get_state(handle, &cur_state);
211 		mutex_unlock(&resource->resource_lock);
212 		if (result)
213 			return result;
214 
215 		if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
216 			break;
217 	}
218 
219 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
220 			  cur_state ? "on" : "off"));
221 
222 	*state = cur_state;
223 	return 0;
224 }
225 
226 static int __acpi_power_on(struct acpi_power_resource *resource)
227 {
228 	acpi_status status = AE_OK;
229 
230 	status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
231 	if (ACPI_FAILURE(status))
232 		return -ENODEV;
233 
234 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
235 			  resource->name));
236 
237 	return 0;
238 }
239 
240 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
241 {
242 	int result = 0;
243 
244 	if (resource->ref_count++) {
245 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
246 				  "Power resource [%s] already on\n",
247 				  resource->name));
248 	} else {
249 		result = __acpi_power_on(resource);
250 		if (result)
251 			resource->ref_count--;
252 	}
253 	return result;
254 }
255 
256 static int acpi_power_on(struct acpi_power_resource *resource)
257 {
258 	int result;
259 
260 	mutex_lock(&resource->resource_lock);
261 	result = acpi_power_on_unlocked(resource);
262 	mutex_unlock(&resource->resource_lock);
263 	return result;
264 }
265 
266 static int __acpi_power_off(struct acpi_power_resource *resource)
267 {
268 	acpi_status status;
269 
270 	status = acpi_evaluate_object(resource->device.handle, "_OFF",
271 				      NULL, NULL);
272 	if (ACPI_FAILURE(status))
273 		return -ENODEV;
274 
275 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
276 			  resource->name));
277 	return 0;
278 }
279 
280 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
281 {
282 	int result = 0;
283 
284 	if (!resource->ref_count) {
285 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
286 				  "Power resource [%s] already off\n",
287 				  resource->name));
288 		return 0;
289 	}
290 
291 	if (--resource->ref_count) {
292 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
293 				  "Power resource [%s] still in use\n",
294 				  resource->name));
295 	} else {
296 		result = __acpi_power_off(resource);
297 		if (result)
298 			resource->ref_count++;
299 	}
300 	return result;
301 }
302 
303 static int acpi_power_off(struct acpi_power_resource *resource)
304 {
305 	int result;
306 
307 	mutex_lock(&resource->resource_lock);
308 	result = acpi_power_off_unlocked(resource);
309 	mutex_unlock(&resource->resource_lock);
310 	return result;
311 }
312 
313 static int acpi_power_off_list(struct list_head *list)
314 {
315 	struct acpi_power_resource_entry *entry;
316 	int result = 0;
317 
318 	list_for_each_entry_reverse(entry, list, node) {
319 		result = acpi_power_off(entry->resource);
320 		if (result)
321 			goto err;
322 	}
323 	return 0;
324 
325  err:
326 	list_for_each_entry_continue(entry, list, node)
327 		acpi_power_on(entry->resource);
328 
329 	return result;
330 }
331 
332 static int acpi_power_on_list(struct list_head *list)
333 {
334 	struct acpi_power_resource_entry *entry;
335 	int result = 0;
336 
337 	list_for_each_entry(entry, list, node) {
338 		result = acpi_power_on(entry->resource);
339 		if (result)
340 			goto err;
341 	}
342 	return 0;
343 
344  err:
345 	list_for_each_entry_continue_reverse(entry, list, node)
346 		acpi_power_off(entry->resource);
347 
348 	return result;
349 }
350 
351 static struct attribute *attrs[] = {
352 	NULL,
353 };
354 
355 static struct attribute_group attr_groups[] = {
356 	[ACPI_STATE_D0] = {
357 		.name = "power_resources_D0",
358 		.attrs = attrs,
359 	},
360 	[ACPI_STATE_D1] = {
361 		.name = "power_resources_D1",
362 		.attrs = attrs,
363 	},
364 	[ACPI_STATE_D2] = {
365 		.name = "power_resources_D2",
366 		.attrs = attrs,
367 	},
368 	[ACPI_STATE_D3_HOT] = {
369 		.name = "power_resources_D3hot",
370 		.attrs = attrs,
371 	},
372 };
373 
374 static struct attribute_group wakeup_attr_group = {
375 	.name = "power_resources_wakeup",
376 	.attrs = attrs,
377 };
378 
379 static void acpi_power_hide_list(struct acpi_device *adev,
380 				 struct list_head *resources,
381 				 struct attribute_group *attr_group)
382 {
383 	struct acpi_power_resource_entry *entry;
384 
385 	if (list_empty(resources))
386 		return;
387 
388 	list_for_each_entry_reverse(entry, resources, node) {
389 		struct acpi_device *res_dev = &entry->resource->device;
390 
391 		sysfs_remove_link_from_group(&adev->dev.kobj,
392 					     attr_group->name,
393 					     dev_name(&res_dev->dev));
394 	}
395 	sysfs_remove_group(&adev->dev.kobj, attr_group);
396 }
397 
398 static void acpi_power_expose_list(struct acpi_device *adev,
399 				   struct list_head *resources,
400 				   struct attribute_group *attr_group)
401 {
402 	struct acpi_power_resource_entry *entry;
403 	int ret;
404 
405 	if (list_empty(resources))
406 		return;
407 
408 	ret = sysfs_create_group(&adev->dev.kobj, attr_group);
409 	if (ret)
410 		return;
411 
412 	list_for_each_entry(entry, resources, node) {
413 		struct acpi_device *res_dev = &entry->resource->device;
414 
415 		ret = sysfs_add_link_to_group(&adev->dev.kobj,
416 					      attr_group->name,
417 					      &res_dev->dev.kobj,
418 					      dev_name(&res_dev->dev));
419 		if (ret) {
420 			acpi_power_hide_list(adev, resources, attr_group);
421 			break;
422 		}
423 	}
424 }
425 
426 static void acpi_power_expose_hide(struct acpi_device *adev,
427 				   struct list_head *resources,
428 				   struct attribute_group *attr_group,
429 				   bool expose)
430 {
431 	if (expose)
432 		acpi_power_expose_list(adev, resources, attr_group);
433 	else
434 		acpi_power_hide_list(adev, resources, attr_group);
435 }
436 
437 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
438 {
439 	int state;
440 
441 	if (adev->wakeup.flags.valid)
442 		acpi_power_expose_hide(adev, &adev->wakeup.resources,
443 				       &wakeup_attr_group, add);
444 
445 	if (!adev->power.flags.power_resources)
446 		return;
447 
448 	for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
449 		acpi_power_expose_hide(adev,
450 				       &adev->power.states[state].resources,
451 				       &attr_groups[state], add);
452 }
453 
454 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
455 {
456 	struct acpi_power_resource_entry *entry;
457 	int system_level = 5;
458 
459 	list_for_each_entry(entry, list, node) {
460 		struct acpi_power_resource *resource = entry->resource;
461 		acpi_handle handle = resource->device.handle;
462 		int result;
463 		int state;
464 
465 		mutex_lock(&resource->resource_lock);
466 
467 		result = acpi_power_get_state(handle, &state);
468 		if (result) {
469 			mutex_unlock(&resource->resource_lock);
470 			return result;
471 		}
472 		if (state == ACPI_POWER_RESOURCE_STATE_ON) {
473 			resource->ref_count++;
474 			resource->wakeup_enabled = true;
475 		}
476 		if (system_level > resource->system_level)
477 			system_level = resource->system_level;
478 
479 		mutex_unlock(&resource->resource_lock);
480 	}
481 	*system_level_p = system_level;
482 	return 0;
483 }
484 
485 /* --------------------------------------------------------------------------
486                              Device Power Management
487    -------------------------------------------------------------------------- */
488 
489 /**
490  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
491  *                          ACPI 3.0) _PSW (Power State Wake)
492  * @dev: Device to handle.
493  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
494  * @sleep_state: Target sleep state of the system.
495  * @dev_state: Target power state of the device.
496  *
497  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
498  * State Wake) for the device, if present.  On failure reset the device's
499  * wakeup.flags.valid flag.
500  *
501  * RETURN VALUE:
502  * 0 if either _DSW or _PSW has been successfully executed
503  * 0 if neither _DSW nor _PSW has been found
504  * -ENODEV if the execution of either _DSW or _PSW has failed
505  */
506 int acpi_device_sleep_wake(struct acpi_device *dev,
507                            int enable, int sleep_state, int dev_state)
508 {
509 	union acpi_object in_arg[3];
510 	struct acpi_object_list arg_list = { 3, in_arg };
511 	acpi_status status = AE_OK;
512 
513 	/*
514 	 * Try to execute _DSW first.
515 	 *
516 	 * Three agruments are needed for the _DSW object:
517 	 * Argument 0: enable/disable the wake capabilities
518 	 * Argument 1: target system state
519 	 * Argument 2: target device state
520 	 * When _DSW object is called to disable the wake capabilities, maybe
521 	 * the first argument is filled. The values of the other two agruments
522 	 * are meaningless.
523 	 */
524 	in_arg[0].type = ACPI_TYPE_INTEGER;
525 	in_arg[0].integer.value = enable;
526 	in_arg[1].type = ACPI_TYPE_INTEGER;
527 	in_arg[1].integer.value = sleep_state;
528 	in_arg[2].type = ACPI_TYPE_INTEGER;
529 	in_arg[2].integer.value = dev_state;
530 	status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
531 	if (ACPI_SUCCESS(status)) {
532 		return 0;
533 	} else if (status != AE_NOT_FOUND) {
534 		printk(KERN_ERR PREFIX "_DSW execution failed\n");
535 		dev->wakeup.flags.valid = 0;
536 		return -ENODEV;
537 	}
538 
539 	/* Execute _PSW */
540 	status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
541 	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
542 		printk(KERN_ERR PREFIX "_PSW execution failed\n");
543 		dev->wakeup.flags.valid = 0;
544 		return -ENODEV;
545 	}
546 
547 	return 0;
548 }
549 
550 /*
551  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
552  * 1. Power on the power resources required for the wakeup device
553  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
554  *    State Wake) for the device, if present
555  */
556 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
557 {
558 	struct acpi_power_resource_entry *entry;
559 	int err = 0;
560 
561 	if (!dev || !dev->wakeup.flags.valid)
562 		return -EINVAL;
563 
564 	mutex_lock(&acpi_device_lock);
565 
566 	if (dev->wakeup.prepare_count++)
567 		goto out;
568 
569 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
570 		struct acpi_power_resource *resource = entry->resource;
571 
572 		mutex_lock(&resource->resource_lock);
573 
574 		if (!resource->wakeup_enabled) {
575 			err = acpi_power_on_unlocked(resource);
576 			if (!err)
577 				resource->wakeup_enabled = true;
578 		}
579 
580 		mutex_unlock(&resource->resource_lock);
581 
582 		if (err) {
583 			dev_err(&dev->dev,
584 				"Cannot turn wakeup power resources on\n");
585 			dev->wakeup.flags.valid = 0;
586 			goto out;
587 		}
588 	}
589 	/*
590 	 * Passing 3 as the third argument below means the device may be
591 	 * put into arbitrary power state afterward.
592 	 */
593 	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
594 	if (err)
595 		dev->wakeup.prepare_count = 0;
596 
597  out:
598 	mutex_unlock(&acpi_device_lock);
599 	return err;
600 }
601 
602 /*
603  * Shutdown a wakeup device, counterpart of above method
604  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
605  *    State Wake) for the device, if present
606  * 2. Shutdown down the power resources
607  */
608 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
609 {
610 	struct acpi_power_resource_entry *entry;
611 	int err = 0;
612 
613 	if (!dev || !dev->wakeup.flags.valid)
614 		return -EINVAL;
615 
616 	mutex_lock(&acpi_device_lock);
617 
618 	if (--dev->wakeup.prepare_count > 0)
619 		goto out;
620 
621 	/*
622 	 * Executing the code below even if prepare_count is already zero when
623 	 * the function is called may be useful, for example for initialisation.
624 	 */
625 	if (dev->wakeup.prepare_count < 0)
626 		dev->wakeup.prepare_count = 0;
627 
628 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
629 	if (err)
630 		goto out;
631 
632 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
633 		struct acpi_power_resource *resource = entry->resource;
634 
635 		mutex_lock(&resource->resource_lock);
636 
637 		if (resource->wakeup_enabled) {
638 			err = acpi_power_off_unlocked(resource);
639 			if (!err)
640 				resource->wakeup_enabled = false;
641 		}
642 
643 		mutex_unlock(&resource->resource_lock);
644 
645 		if (err) {
646 			dev_err(&dev->dev,
647 				"Cannot turn wakeup power resources off\n");
648 			dev->wakeup.flags.valid = 0;
649 			break;
650 		}
651 	}
652 
653  out:
654 	mutex_unlock(&acpi_device_lock);
655 	return err;
656 }
657 
658 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
659 {
660 	int result = 0;
661 	int list_state = 0;
662 	int i = 0;
663 
664 	if (!device || !state)
665 		return -EINVAL;
666 
667 	/*
668 	 * We know a device's inferred power state when all the resources
669 	 * required for a given D-state are 'on'.
670 	 */
671 	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
672 		struct list_head *list = &device->power.states[i].resources;
673 
674 		if (list_empty(list))
675 			continue;
676 
677 		result = acpi_power_get_list_state(list, &list_state);
678 		if (result)
679 			return result;
680 
681 		if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
682 			*state = i;
683 			return 0;
684 		}
685 	}
686 
687 	*state = device->power.states[ACPI_STATE_D3_COLD].flags.valid ?
688 		ACPI_STATE_D3_COLD : ACPI_STATE_D3_HOT;
689 	return 0;
690 }
691 
692 int acpi_power_on_resources(struct acpi_device *device, int state)
693 {
694 	if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
695 		return -EINVAL;
696 
697 	return acpi_power_on_list(&device->power.states[state].resources);
698 }
699 
700 int acpi_power_transition(struct acpi_device *device, int state)
701 {
702 	int result = 0;
703 
704 	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
705 		return -EINVAL;
706 
707 	if (device->power.state == state || !device->flags.power_manageable)
708 		return 0;
709 
710 	if ((device->power.state < ACPI_STATE_D0)
711 	    || (device->power.state > ACPI_STATE_D3_COLD))
712 		return -ENODEV;
713 
714 	/*
715 	 * First we reference all power resources required in the target list
716 	 * (e.g. so the device doesn't lose power while transitioning).  Then,
717 	 * we dereference all power resources used in the current list.
718 	 */
719 	if (state < ACPI_STATE_D3_COLD)
720 		result = acpi_power_on_list(
721 			&device->power.states[state].resources);
722 
723 	if (!result && device->power.state < ACPI_STATE_D3_COLD)
724 		acpi_power_off_list(
725 			&device->power.states[device->power.state].resources);
726 
727 	/* We shouldn't change the state unless the above operations succeed. */
728 	device->power.state = result ? ACPI_STATE_UNKNOWN : state;
729 
730 	return result;
731 }
732 
733 static void acpi_release_power_resource(struct device *dev)
734 {
735 	struct acpi_device *device = to_acpi_device(dev);
736 	struct acpi_power_resource *resource;
737 
738 	resource = container_of(device, struct acpi_power_resource, device);
739 
740 	mutex_lock(&power_resource_list_lock);
741 	list_del(&resource->list_node);
742 	mutex_unlock(&power_resource_list_lock);
743 
744 	acpi_free_pnp_ids(&device->pnp);
745 	kfree(resource);
746 }
747 
748 static ssize_t acpi_power_in_use_show(struct device *dev,
749 				      struct device_attribute *attr,
750 				      char *buf) {
751 	struct acpi_power_resource *resource;
752 
753 	resource = to_power_resource(to_acpi_device(dev));
754 	return sprintf(buf, "%u\n", !!resource->ref_count);
755 }
756 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
757 
758 static void acpi_power_sysfs_remove(struct acpi_device *device)
759 {
760 	device_remove_file(&device->dev, &dev_attr_resource_in_use);
761 }
762 
763 static void acpi_power_add_resource_to_list(struct acpi_power_resource *resource)
764 {
765 	mutex_lock(&power_resource_list_lock);
766 
767 	if (!list_empty(&acpi_power_resource_list)) {
768 		struct acpi_power_resource *r;
769 
770 		list_for_each_entry(r, &acpi_power_resource_list, list_node)
771 			if (r->order > resource->order) {
772 				list_add_tail(&resource->list_node, &r->list_node);
773 				goto out;
774 			}
775 	}
776 	list_add_tail(&resource->list_node, &acpi_power_resource_list);
777 
778  out:
779 	mutex_unlock(&power_resource_list_lock);
780 }
781 
782 int acpi_add_power_resource(acpi_handle handle)
783 {
784 	struct acpi_power_resource *resource;
785 	struct acpi_device *device = NULL;
786 	union acpi_object acpi_object;
787 	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
788 	acpi_status status;
789 	int state, result = -ENODEV;
790 
791 	acpi_bus_get_device(handle, &device);
792 	if (device)
793 		return 0;
794 
795 	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
796 	if (!resource)
797 		return -ENOMEM;
798 
799 	device = &resource->device;
800 	acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
801 				ACPI_STA_DEFAULT);
802 	mutex_init(&resource->resource_lock);
803 	INIT_LIST_HEAD(&resource->list_node);
804 	resource->name = device->pnp.bus_id;
805 	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
806 	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
807 	device->power.state = ACPI_STATE_UNKNOWN;
808 
809 	/* Evalute the object to get the system level and resource order. */
810 	status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
811 	if (ACPI_FAILURE(status))
812 		goto err;
813 
814 	resource->system_level = acpi_object.power_resource.system_level;
815 	resource->order = acpi_object.power_resource.resource_order;
816 
817 	result = acpi_power_get_state(handle, &state);
818 	if (result)
819 		goto err;
820 
821 	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
822 	       acpi_device_bid(device), state ? "on" : "off");
823 
824 	device->flags.match_driver = true;
825 	result = acpi_device_add(device, acpi_release_power_resource);
826 	if (result)
827 		goto err;
828 
829 	if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
830 		device->remove = acpi_power_sysfs_remove;
831 
832 	acpi_power_add_resource_to_list(resource);
833 	acpi_device_add_finalize(device);
834 	return 0;
835 
836  err:
837 	acpi_release_power_resource(&device->dev);
838 	return result;
839 }
840 
841 #ifdef CONFIG_ACPI_SLEEP
842 void acpi_resume_power_resources(void)
843 {
844 	struct acpi_power_resource *resource;
845 
846 	mutex_lock(&power_resource_list_lock);
847 
848 	list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
849 		int result, state;
850 
851 		mutex_lock(&resource->resource_lock);
852 
853 		result = acpi_power_get_state(resource->device.handle, &state);
854 		if (result) {
855 			mutex_unlock(&resource->resource_lock);
856 			continue;
857 		}
858 
859 		if (state == ACPI_POWER_RESOURCE_STATE_OFF
860 		    && resource->ref_count) {
861 			dev_info(&resource->device.dev, "Turning ON\n");
862 			__acpi_power_on(resource);
863 		}
864 
865 		mutex_unlock(&resource->resource_lock);
866 	}
867 	list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
868 		int result, state;
869 
870 		mutex_lock(&resource->resource_lock);
871 
872 		result = acpi_power_get_state(resource->device.handle, &state);
873 		if (result) {
874 			mutex_unlock(&resource->resource_lock);
875 			continue;
876 		}
877 
878 		if (state == ACPI_POWER_RESOURCE_STATE_ON
879 		    && !resource->ref_count) {
880 			dev_info(&resource->device.dev, "Turning OFF\n");
881 			__acpi_power_off(resource);
882 		}
883 
884 		mutex_unlock(&resource->resource_lock);
885 	}
886 
887 	mutex_unlock(&power_resource_list_lock);
888 }
889 #endif
890