xref: /openbmc/linux/drivers/acpi/power.c (revision bc000245)
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 <acpi/acpi_bus.h>
46 #include <acpi/acpi_drivers.h>
47 #include "sleep.h"
48 #include "internal.h"
49 
50 #define PREFIX "ACPI: "
51 
52 #define _COMPONENT			ACPI_POWER_COMPONENT
53 ACPI_MODULE_NAME("power");
54 #define ACPI_POWER_CLASS		"power_resource"
55 #define ACPI_POWER_DEVICE_NAME		"Power Resource"
56 #define ACPI_POWER_FILE_INFO		"info"
57 #define ACPI_POWER_FILE_STATUS		"state"
58 #define ACPI_POWER_RESOURCE_STATE_OFF	0x00
59 #define ACPI_POWER_RESOURCE_STATE_ON	0x01
60 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
61 
62 struct acpi_power_resource {
63 	struct acpi_device device;
64 	struct list_head list_node;
65 	char *name;
66 	u32 system_level;
67 	u32 order;
68 	unsigned int ref_count;
69 	bool wakeup_enabled;
70 	struct mutex resource_lock;
71 };
72 
73 struct acpi_power_resource_entry {
74 	struct list_head node;
75 	struct acpi_power_resource *resource;
76 };
77 
78 static LIST_HEAD(acpi_power_resource_list);
79 static DEFINE_MUTEX(power_resource_list_lock);
80 
81 /* --------------------------------------------------------------------------
82                              Power Resource Management
83    -------------------------------------------------------------------------- */
84 
85 static inline
86 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
87 {
88 	return container_of(device, struct acpi_power_resource, device);
89 }
90 
91 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
92 {
93 	struct acpi_device *device;
94 
95 	if (acpi_bus_get_device(handle, &device))
96 		return NULL;
97 
98 	return to_power_resource(device);
99 }
100 
101 static int acpi_power_resources_list_add(acpi_handle handle,
102 					 struct list_head *list)
103 {
104 	struct acpi_power_resource *resource = acpi_power_get_context(handle);
105 	struct acpi_power_resource_entry *entry;
106 
107 	if (!resource || !list)
108 		return -EINVAL;
109 
110 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
111 	if (!entry)
112 		return -ENOMEM;
113 
114 	entry->resource = resource;
115 	if (!list_empty(list)) {
116 		struct acpi_power_resource_entry *e;
117 
118 		list_for_each_entry(e, list, node)
119 			if (e->resource->order > resource->order) {
120 				list_add_tail(&entry->node, &e->node);
121 				return 0;
122 			}
123 	}
124 	list_add_tail(&entry->node, list);
125 	return 0;
126 }
127 
128 void acpi_power_resources_list_free(struct list_head *list)
129 {
130 	struct acpi_power_resource_entry *entry, *e;
131 
132 	list_for_each_entry_safe(entry, e, list, node) {
133 		list_del(&entry->node);
134 		kfree(entry);
135 	}
136 }
137 
138 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
139 				 struct list_head *list)
140 {
141 	unsigned int i;
142 	int err = 0;
143 
144 	for (i = start; i < package->package.count; i++) {
145 		union acpi_object *element = &package->package.elements[i];
146 		acpi_handle rhandle;
147 
148 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
149 			err = -ENODATA;
150 			break;
151 		}
152 		rhandle = element->reference.handle;
153 		if (!rhandle) {
154 			err = -ENODEV;
155 			break;
156 		}
157 		err = acpi_add_power_resource(rhandle);
158 		if (err)
159 			break;
160 
161 		err = acpi_power_resources_list_add(rhandle, list);
162 		if (err)
163 			break;
164 	}
165 	if (err)
166 		acpi_power_resources_list_free(list);
167 
168 	return err;
169 }
170 
171 static int acpi_power_get_state(acpi_handle handle, int *state)
172 {
173 	acpi_status status = AE_OK;
174 	unsigned long long sta = 0;
175 	char node_name[5];
176 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
177 
178 
179 	if (!handle || !state)
180 		return -EINVAL;
181 
182 	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
183 	if (ACPI_FAILURE(status))
184 		return -ENODEV;
185 
186 	*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
187 			      ACPI_POWER_RESOURCE_STATE_OFF;
188 
189 	acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
190 
191 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
192 			  node_name,
193 				*state ? "on" : "off"));
194 
195 	return 0;
196 }
197 
198 static int acpi_power_get_list_state(struct list_head *list, int *state)
199 {
200 	struct acpi_power_resource_entry *entry;
201 	int cur_state;
202 
203 	if (!list || !state)
204 		return -EINVAL;
205 
206 	/* The state of the list is 'on' IFF all resources are 'on'. */
207 	list_for_each_entry(entry, list, node) {
208 		struct acpi_power_resource *resource = entry->resource;
209 		acpi_handle handle = resource->device.handle;
210 		int result;
211 
212 		mutex_lock(&resource->resource_lock);
213 		result = acpi_power_get_state(handle, &cur_state);
214 		mutex_unlock(&resource->resource_lock);
215 		if (result)
216 			return result;
217 
218 		if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
219 			break;
220 	}
221 
222 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
223 			  cur_state ? "on" : "off"));
224 
225 	*state = cur_state;
226 	return 0;
227 }
228 
229 static int __acpi_power_on(struct acpi_power_resource *resource)
230 {
231 	acpi_status status = AE_OK;
232 
233 	status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
234 	if (ACPI_FAILURE(status))
235 		return -ENODEV;
236 
237 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
238 			  resource->name));
239 
240 	return 0;
241 }
242 
243 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
244 {
245 	int result = 0;
246 
247 	if (resource->ref_count++) {
248 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
249 				  "Power resource [%s] already on\n",
250 				  resource->name));
251 	} else {
252 		result = __acpi_power_on(resource);
253 		if (result)
254 			resource->ref_count--;
255 	}
256 	return result;
257 }
258 
259 static int acpi_power_on(struct acpi_power_resource *resource)
260 {
261 	int result;
262 
263 	mutex_lock(&resource->resource_lock);
264 	result = acpi_power_on_unlocked(resource);
265 	mutex_unlock(&resource->resource_lock);
266 	return result;
267 }
268 
269 static int __acpi_power_off(struct acpi_power_resource *resource)
270 {
271 	acpi_status status;
272 
273 	status = acpi_evaluate_object(resource->device.handle, "_OFF",
274 				      NULL, NULL);
275 	if (ACPI_FAILURE(status))
276 		return -ENODEV;
277 
278 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
279 			  resource->name));
280 	return 0;
281 }
282 
283 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
284 {
285 	int result = 0;
286 
287 	if (!resource->ref_count) {
288 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
289 				  "Power resource [%s] already off\n",
290 				  resource->name));
291 		return 0;
292 	}
293 
294 	if (--resource->ref_count) {
295 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
296 				  "Power resource [%s] still in use\n",
297 				  resource->name));
298 	} else {
299 		result = __acpi_power_off(resource);
300 		if (result)
301 			resource->ref_count++;
302 	}
303 	return result;
304 }
305 
306 static int acpi_power_off(struct acpi_power_resource *resource)
307 {
308 	int result;
309 
310 	mutex_lock(&resource->resource_lock);
311 	result = acpi_power_off_unlocked(resource);
312 	mutex_unlock(&resource->resource_lock);
313 	return result;
314 }
315 
316 static int acpi_power_off_list(struct list_head *list)
317 {
318 	struct acpi_power_resource_entry *entry;
319 	int result = 0;
320 
321 	list_for_each_entry_reverse(entry, list, node) {
322 		result = acpi_power_off(entry->resource);
323 		if (result)
324 			goto err;
325 	}
326 	return 0;
327 
328  err:
329 	list_for_each_entry_continue(entry, list, node)
330 		acpi_power_on(entry->resource);
331 
332 	return result;
333 }
334 
335 static int acpi_power_on_list(struct list_head *list)
336 {
337 	struct acpi_power_resource_entry *entry;
338 	int result = 0;
339 
340 	list_for_each_entry(entry, list, node) {
341 		result = acpi_power_on(entry->resource);
342 		if (result)
343 			goto err;
344 	}
345 	return 0;
346 
347  err:
348 	list_for_each_entry_continue_reverse(entry, list, node)
349 		acpi_power_off(entry->resource);
350 
351 	return result;
352 }
353 
354 static struct attribute *attrs[] = {
355 	NULL,
356 };
357 
358 static struct attribute_group attr_groups[] = {
359 	[ACPI_STATE_D0] = {
360 		.name = "power_resources_D0",
361 		.attrs = attrs,
362 	},
363 	[ACPI_STATE_D1] = {
364 		.name = "power_resources_D1",
365 		.attrs = attrs,
366 	},
367 	[ACPI_STATE_D2] = {
368 		.name = "power_resources_D2",
369 		.attrs = attrs,
370 	},
371 	[ACPI_STATE_D3_HOT] = {
372 		.name = "power_resources_D3hot",
373 		.attrs = attrs,
374 	},
375 };
376 
377 static struct attribute_group wakeup_attr_group = {
378 	.name = "power_resources_wakeup",
379 	.attrs = attrs,
380 };
381 
382 static void acpi_power_hide_list(struct acpi_device *adev,
383 				 struct list_head *resources,
384 				 struct attribute_group *attr_group)
385 {
386 	struct acpi_power_resource_entry *entry;
387 
388 	if (list_empty(resources))
389 		return;
390 
391 	list_for_each_entry_reverse(entry, resources, node) {
392 		struct acpi_device *res_dev = &entry->resource->device;
393 
394 		sysfs_remove_link_from_group(&adev->dev.kobj,
395 					     attr_group->name,
396 					     dev_name(&res_dev->dev));
397 	}
398 	sysfs_remove_group(&adev->dev.kobj, attr_group);
399 }
400 
401 static void acpi_power_expose_list(struct acpi_device *adev,
402 				   struct list_head *resources,
403 				   struct attribute_group *attr_group)
404 {
405 	struct acpi_power_resource_entry *entry;
406 	int ret;
407 
408 	if (list_empty(resources))
409 		return;
410 
411 	ret = sysfs_create_group(&adev->dev.kobj, attr_group);
412 	if (ret)
413 		return;
414 
415 	list_for_each_entry(entry, resources, node) {
416 		struct acpi_device *res_dev = &entry->resource->device;
417 
418 		ret = sysfs_add_link_to_group(&adev->dev.kobj,
419 					      attr_group->name,
420 					      &res_dev->dev.kobj,
421 					      dev_name(&res_dev->dev));
422 		if (ret) {
423 			acpi_power_hide_list(adev, resources, attr_group);
424 			break;
425 		}
426 	}
427 }
428 
429 static void acpi_power_expose_hide(struct acpi_device *adev,
430 				   struct list_head *resources,
431 				   struct attribute_group *attr_group,
432 				   bool expose)
433 {
434 	if (expose)
435 		acpi_power_expose_list(adev, resources, attr_group);
436 	else
437 		acpi_power_hide_list(adev, resources, attr_group);
438 }
439 
440 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
441 {
442 	int state;
443 
444 	if (adev->wakeup.flags.valid)
445 		acpi_power_expose_hide(adev, &adev->wakeup.resources,
446 				       &wakeup_attr_group, add);
447 
448 	if (!adev->power.flags.power_resources)
449 		return;
450 
451 	for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
452 		acpi_power_expose_hide(adev,
453 				       &adev->power.states[state].resources,
454 				       &attr_groups[state], add);
455 }
456 
457 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
458 {
459 	struct acpi_power_resource_entry *entry;
460 	int system_level = 5;
461 
462 	list_for_each_entry(entry, list, node) {
463 		struct acpi_power_resource *resource = entry->resource;
464 		acpi_handle handle = resource->device.handle;
465 		int result;
466 		int state;
467 
468 		mutex_lock(&resource->resource_lock);
469 
470 		result = acpi_power_get_state(handle, &state);
471 		if (result) {
472 			mutex_unlock(&resource->resource_lock);
473 			return result;
474 		}
475 		if (state == ACPI_POWER_RESOURCE_STATE_ON) {
476 			resource->ref_count++;
477 			resource->wakeup_enabled = true;
478 		}
479 		if (system_level > resource->system_level)
480 			system_level = resource->system_level;
481 
482 		mutex_unlock(&resource->resource_lock);
483 	}
484 	*system_level_p = system_level;
485 	return 0;
486 }
487 
488 /* --------------------------------------------------------------------------
489                              Device Power Management
490    -------------------------------------------------------------------------- */
491 
492 /**
493  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
494  *                          ACPI 3.0) _PSW (Power State Wake)
495  * @dev: Device to handle.
496  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
497  * @sleep_state: Target sleep state of the system.
498  * @dev_state: Target power state of the device.
499  *
500  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
501  * State Wake) for the device, if present.  On failure reset the device's
502  * wakeup.flags.valid flag.
503  *
504  * RETURN VALUE:
505  * 0 if either _DSW or _PSW has been successfully executed
506  * 0 if neither _DSW nor _PSW has been found
507  * -ENODEV if the execution of either _DSW or _PSW has failed
508  */
509 int acpi_device_sleep_wake(struct acpi_device *dev,
510                            int enable, int sleep_state, int dev_state)
511 {
512 	union acpi_object in_arg[3];
513 	struct acpi_object_list arg_list = { 3, in_arg };
514 	acpi_status status = AE_OK;
515 
516 	/*
517 	 * Try to execute _DSW first.
518 	 *
519 	 * Three agruments are needed for the _DSW object:
520 	 * Argument 0: enable/disable the wake capabilities
521 	 * Argument 1: target system state
522 	 * Argument 2: target device state
523 	 * When _DSW object is called to disable the wake capabilities, maybe
524 	 * the first argument is filled. The values of the other two agruments
525 	 * are meaningless.
526 	 */
527 	in_arg[0].type = ACPI_TYPE_INTEGER;
528 	in_arg[0].integer.value = enable;
529 	in_arg[1].type = ACPI_TYPE_INTEGER;
530 	in_arg[1].integer.value = sleep_state;
531 	in_arg[2].type = ACPI_TYPE_INTEGER;
532 	in_arg[2].integer.value = dev_state;
533 	status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
534 	if (ACPI_SUCCESS(status)) {
535 		return 0;
536 	} else if (status != AE_NOT_FOUND) {
537 		printk(KERN_ERR PREFIX "_DSW execution failed\n");
538 		dev->wakeup.flags.valid = 0;
539 		return -ENODEV;
540 	}
541 
542 	/* Execute _PSW */
543 	status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
544 	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
545 		printk(KERN_ERR PREFIX "_PSW execution failed\n");
546 		dev->wakeup.flags.valid = 0;
547 		return -ENODEV;
548 	}
549 
550 	return 0;
551 }
552 
553 /*
554  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
555  * 1. Power on the power resources required for the wakeup device
556  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
557  *    State Wake) for the device, if present
558  */
559 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
560 {
561 	struct acpi_power_resource_entry *entry;
562 	int err = 0;
563 
564 	if (!dev || !dev->wakeup.flags.valid)
565 		return -EINVAL;
566 
567 	mutex_lock(&acpi_device_lock);
568 
569 	if (dev->wakeup.prepare_count++)
570 		goto out;
571 
572 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
573 		struct acpi_power_resource *resource = entry->resource;
574 
575 		mutex_lock(&resource->resource_lock);
576 
577 		if (!resource->wakeup_enabled) {
578 			err = acpi_power_on_unlocked(resource);
579 			if (!err)
580 				resource->wakeup_enabled = true;
581 		}
582 
583 		mutex_unlock(&resource->resource_lock);
584 
585 		if (err) {
586 			dev_err(&dev->dev,
587 				"Cannot turn wakeup power resources on\n");
588 			dev->wakeup.flags.valid = 0;
589 			goto out;
590 		}
591 	}
592 	/*
593 	 * Passing 3 as the third argument below means the device may be
594 	 * put into arbitrary power state afterward.
595 	 */
596 	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
597 	if (err)
598 		dev->wakeup.prepare_count = 0;
599 
600  out:
601 	mutex_unlock(&acpi_device_lock);
602 	return err;
603 }
604 
605 /*
606  * Shutdown a wakeup device, counterpart of above method
607  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
608  *    State Wake) for the device, if present
609  * 2. Shutdown down the power resources
610  */
611 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
612 {
613 	struct acpi_power_resource_entry *entry;
614 	int err = 0;
615 
616 	if (!dev || !dev->wakeup.flags.valid)
617 		return -EINVAL;
618 
619 	mutex_lock(&acpi_device_lock);
620 
621 	if (--dev->wakeup.prepare_count > 0)
622 		goto out;
623 
624 	/*
625 	 * Executing the code below even if prepare_count is already zero when
626 	 * the function is called may be useful, for example for initialisation.
627 	 */
628 	if (dev->wakeup.prepare_count < 0)
629 		dev->wakeup.prepare_count = 0;
630 
631 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
632 	if (err)
633 		goto out;
634 
635 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
636 		struct acpi_power_resource *resource = entry->resource;
637 
638 		mutex_lock(&resource->resource_lock);
639 
640 		if (resource->wakeup_enabled) {
641 			err = acpi_power_off_unlocked(resource);
642 			if (!err)
643 				resource->wakeup_enabled = false;
644 		}
645 
646 		mutex_unlock(&resource->resource_lock);
647 
648 		if (err) {
649 			dev_err(&dev->dev,
650 				"Cannot turn wakeup power resources off\n");
651 			dev->wakeup.flags.valid = 0;
652 			break;
653 		}
654 	}
655 
656  out:
657 	mutex_unlock(&acpi_device_lock);
658 	return err;
659 }
660 
661 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
662 {
663 	int result = 0;
664 	int list_state = 0;
665 	int i = 0;
666 
667 	if (!device || !state)
668 		return -EINVAL;
669 
670 	/*
671 	 * We know a device's inferred power state when all the resources
672 	 * required for a given D-state are 'on'.
673 	 */
674 	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
675 		struct list_head *list = &device->power.states[i].resources;
676 
677 		if (list_empty(list))
678 			continue;
679 
680 		result = acpi_power_get_list_state(list, &list_state);
681 		if (result)
682 			return result;
683 
684 		if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
685 			*state = i;
686 			return 0;
687 		}
688 	}
689 
690 	*state = ACPI_STATE_D3_COLD;
691 	return 0;
692 }
693 
694 int acpi_power_on_resources(struct acpi_device *device, int state)
695 {
696 	if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
697 		return -EINVAL;
698 
699 	return acpi_power_on_list(&device->power.states[state].resources);
700 }
701 
702 int acpi_power_transition(struct acpi_device *device, int state)
703 {
704 	int result = 0;
705 
706 	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
707 		return -EINVAL;
708 
709 	if (device->power.state == state || !device->flags.power_manageable)
710 		return 0;
711 
712 	if ((device->power.state < ACPI_STATE_D0)
713 	    || (device->power.state > ACPI_STATE_D3_COLD))
714 		return -ENODEV;
715 
716 	/* TBD: Resources must be ordered. */
717 
718 	/*
719 	 * First we reference all power resources required in the target list
720 	 * (e.g. so the device doesn't lose power while transitioning).  Then,
721 	 * we dereference all power resources used in the current list.
722 	 */
723 	if (state < ACPI_STATE_D3_COLD)
724 		result = acpi_power_on_list(
725 			&device->power.states[state].resources);
726 
727 	if (!result && device->power.state < ACPI_STATE_D3_COLD)
728 		acpi_power_off_list(
729 			&device->power.states[device->power.state].resources);
730 
731 	/* We shouldn't change the state unless the above operations succeed. */
732 	device->power.state = result ? ACPI_STATE_UNKNOWN : state;
733 
734 	return result;
735 }
736 
737 static void acpi_release_power_resource(struct device *dev)
738 {
739 	struct acpi_device *device = to_acpi_device(dev);
740 	struct acpi_power_resource *resource;
741 
742 	resource = container_of(device, struct acpi_power_resource, device);
743 
744 	mutex_lock(&power_resource_list_lock);
745 	list_del(&resource->list_node);
746 	mutex_unlock(&power_resource_list_lock);
747 
748 	acpi_free_pnp_ids(&device->pnp);
749 	kfree(resource);
750 }
751 
752 static ssize_t acpi_power_in_use_show(struct device *dev,
753 				      struct device_attribute *attr,
754 				      char *buf) {
755 	struct acpi_power_resource *resource;
756 
757 	resource = to_power_resource(to_acpi_device(dev));
758 	return sprintf(buf, "%u\n", !!resource->ref_count);
759 }
760 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
761 
762 static void acpi_power_sysfs_remove(struct acpi_device *device)
763 {
764 	device_remove_file(&device->dev, &dev_attr_resource_in_use);
765 }
766 
767 int acpi_add_power_resource(acpi_handle handle)
768 {
769 	struct acpi_power_resource *resource;
770 	struct acpi_device *device = NULL;
771 	union acpi_object acpi_object;
772 	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
773 	acpi_status status;
774 	int state, result = -ENODEV;
775 
776 	acpi_bus_get_device(handle, &device);
777 	if (device)
778 		return 0;
779 
780 	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
781 	if (!resource)
782 		return -ENOMEM;
783 
784 	device = &resource->device;
785 	acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
786 				ACPI_STA_DEFAULT);
787 	mutex_init(&resource->resource_lock);
788 	INIT_LIST_HEAD(&resource->list_node);
789 	resource->name = device->pnp.bus_id;
790 	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
791 	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
792 	device->power.state = ACPI_STATE_UNKNOWN;
793 
794 	/* Evalute the object to get the system level and resource order. */
795 	status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
796 	if (ACPI_FAILURE(status))
797 		goto err;
798 
799 	resource->system_level = acpi_object.power_resource.system_level;
800 	resource->order = acpi_object.power_resource.resource_order;
801 
802 	result = acpi_power_get_state(handle, &state);
803 	if (result)
804 		goto err;
805 
806 	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
807 	       acpi_device_bid(device), state ? "on" : "off");
808 
809 	device->flags.match_driver = true;
810 	result = acpi_device_add(device, acpi_release_power_resource);
811 	if (result)
812 		goto err;
813 
814 	if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
815 		device->remove = acpi_power_sysfs_remove;
816 
817 	mutex_lock(&power_resource_list_lock);
818 	list_add(&resource->list_node, &acpi_power_resource_list);
819 	mutex_unlock(&power_resource_list_lock);
820 	acpi_device_add_finalize(device);
821 	return 0;
822 
823  err:
824 	acpi_release_power_resource(&device->dev);
825 	return result;
826 }
827 
828 #ifdef CONFIG_ACPI_SLEEP
829 void acpi_resume_power_resources(void)
830 {
831 	struct acpi_power_resource *resource;
832 
833 	mutex_lock(&power_resource_list_lock);
834 
835 	list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
836 		int result, state;
837 
838 		mutex_lock(&resource->resource_lock);
839 
840 		result = acpi_power_get_state(resource->device.handle, &state);
841 		if (result) {
842 			mutex_unlock(&resource->resource_lock);
843 			continue;
844 		}
845 
846 		if (state == ACPI_POWER_RESOURCE_STATE_OFF
847 		    && resource->ref_count) {
848 			dev_info(&resource->device.dev, "Turning ON\n");
849 			__acpi_power_on(resource);
850 		} else if (state == ACPI_POWER_RESOURCE_STATE_ON
851 		    && !resource->ref_count) {
852 			dev_info(&resource->device.dev, "Turning OFF\n");
853 			__acpi_power_off(resource);
854 		}
855 
856 		mutex_unlock(&resource->resource_lock);
857 	}
858 
859 	mutex_unlock(&power_resource_list_lock);
860 }
861 #endif
862