xref: /openbmc/linux/drivers/acpi/power.c (revision 8e9356c6)
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 PREFIX "ACPI: "
50 
51 #define _COMPONENT			ACPI_POWER_COMPONENT
52 ACPI_MODULE_NAME("power");
53 #define ACPI_POWER_CLASS		"power_resource"
54 #define ACPI_POWER_DEVICE_NAME		"Power Resource"
55 #define ACPI_POWER_FILE_INFO		"info"
56 #define ACPI_POWER_FILE_STATUS		"state"
57 #define ACPI_POWER_RESOURCE_STATE_OFF	0x00
58 #define ACPI_POWER_RESOURCE_STATE_ON	0x01
59 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
60 
61 struct acpi_power_resource {
62 	struct acpi_device device;
63 	struct list_head list_node;
64 	char *name;
65 	u32 system_level;
66 	u32 order;
67 	unsigned int ref_count;
68 	bool wakeup_enabled;
69 	struct mutex resource_lock;
70 };
71 
72 struct acpi_power_resource_entry {
73 	struct list_head node;
74 	struct acpi_power_resource *resource;
75 };
76 
77 static LIST_HEAD(acpi_power_resource_list);
78 static DEFINE_MUTEX(power_resource_list_lock);
79 
80 /* --------------------------------------------------------------------------
81                              Power Resource Management
82    -------------------------------------------------------------------------- */
83 
84 static inline
85 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
86 {
87 	return container_of(device, struct acpi_power_resource, device);
88 }
89 
90 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
91 {
92 	struct acpi_device *device;
93 
94 	if (acpi_bus_get_device(handle, &device))
95 		return NULL;
96 
97 	return to_power_resource(device);
98 }
99 
100 static int acpi_power_resources_list_add(acpi_handle handle,
101 					 struct list_head *list)
102 {
103 	struct acpi_power_resource *resource = acpi_power_get_context(handle);
104 	struct acpi_power_resource_entry *entry;
105 
106 	if (!resource || !list)
107 		return -EINVAL;
108 
109 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
110 	if (!entry)
111 		return -ENOMEM;
112 
113 	entry->resource = resource;
114 	if (!list_empty(list)) {
115 		struct acpi_power_resource_entry *e;
116 
117 		list_for_each_entry(e, list, node)
118 			if (e->resource->order > resource->order) {
119 				list_add_tail(&entry->node, &e->node);
120 				return 0;
121 			}
122 	}
123 	list_add_tail(&entry->node, list);
124 	return 0;
125 }
126 
127 void acpi_power_resources_list_free(struct list_head *list)
128 {
129 	struct acpi_power_resource_entry *entry, *e;
130 
131 	list_for_each_entry_safe(entry, e, list, node) {
132 		list_del(&entry->node);
133 		kfree(entry);
134 	}
135 }
136 
137 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
138 				 struct list_head *list)
139 {
140 	unsigned int i;
141 	int err = 0;
142 
143 	for (i = start; i < package->package.count; i++) {
144 		union acpi_object *element = &package->package.elements[i];
145 		acpi_handle rhandle;
146 
147 		if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
148 			err = -ENODATA;
149 			break;
150 		}
151 		rhandle = element->reference.handle;
152 		if (!rhandle) {
153 			err = -ENODEV;
154 			break;
155 		}
156 		err = acpi_add_power_resource(rhandle);
157 		if (err)
158 			break;
159 
160 		err = acpi_power_resources_list_add(rhandle, list);
161 		if (err)
162 			break;
163 	}
164 	if (err)
165 		acpi_power_resources_list_free(list);
166 
167 	return err;
168 }
169 
170 static int acpi_power_get_state(acpi_handle handle, int *state)
171 {
172 	acpi_status status = AE_OK;
173 	unsigned long long sta = 0;
174 	char node_name[5];
175 	struct acpi_buffer buffer = { sizeof(node_name), node_name };
176 
177 
178 	if (!handle || !state)
179 		return -EINVAL;
180 
181 	status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
182 	if (ACPI_FAILURE(status))
183 		return -ENODEV;
184 
185 	*state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
186 			      ACPI_POWER_RESOURCE_STATE_OFF;
187 
188 	acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
189 
190 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
191 			  node_name,
192 				*state ? "on" : "off"));
193 
194 	return 0;
195 }
196 
197 static int acpi_power_get_list_state(struct list_head *list, int *state)
198 {
199 	struct acpi_power_resource_entry *entry;
200 	int cur_state;
201 
202 	if (!list || !state)
203 		return -EINVAL;
204 
205 	/* The state of the list is 'on' IFF all resources are 'on'. */
206 	list_for_each_entry(entry, list, node) {
207 		struct acpi_power_resource *resource = entry->resource;
208 		acpi_handle handle = resource->device.handle;
209 		int result;
210 
211 		mutex_lock(&resource->resource_lock);
212 		result = acpi_power_get_state(handle, &cur_state);
213 		mutex_unlock(&resource->resource_lock);
214 		if (result)
215 			return result;
216 
217 		if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
218 			break;
219 	}
220 
221 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
222 			  cur_state ? "on" : "off"));
223 
224 	*state = cur_state;
225 	return 0;
226 }
227 
228 static int __acpi_power_on(struct acpi_power_resource *resource)
229 {
230 	acpi_status status = AE_OK;
231 
232 	status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
233 	if (ACPI_FAILURE(status))
234 		return -ENODEV;
235 
236 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
237 			  resource->name));
238 
239 	return 0;
240 }
241 
242 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
243 {
244 	int result = 0;
245 
246 	if (resource->ref_count++) {
247 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
248 				  "Power resource [%s] already on\n",
249 				  resource->name));
250 	} else {
251 		result = __acpi_power_on(resource);
252 		if (result)
253 			resource->ref_count--;
254 	}
255 	return result;
256 }
257 
258 static int acpi_power_on(struct acpi_power_resource *resource)
259 {
260 	int result;
261 
262 	mutex_lock(&resource->resource_lock);
263 	result = acpi_power_on_unlocked(resource);
264 	mutex_unlock(&resource->resource_lock);
265 	return result;
266 }
267 
268 static int __acpi_power_off(struct acpi_power_resource *resource)
269 {
270 	acpi_status status;
271 
272 	status = acpi_evaluate_object(resource->device.handle, "_OFF",
273 				      NULL, NULL);
274 	if (ACPI_FAILURE(status))
275 		return -ENODEV;
276 
277 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
278 			  resource->name));
279 	return 0;
280 }
281 
282 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
283 {
284 	int result = 0;
285 
286 	if (!resource->ref_count) {
287 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
288 				  "Power resource [%s] already off\n",
289 				  resource->name));
290 		return 0;
291 	}
292 
293 	if (--resource->ref_count) {
294 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
295 				  "Power resource [%s] still in use\n",
296 				  resource->name));
297 	} else {
298 		result = __acpi_power_off(resource);
299 		if (result)
300 			resource->ref_count++;
301 	}
302 	return result;
303 }
304 
305 static int acpi_power_off(struct acpi_power_resource *resource)
306 {
307 	int result;
308 
309 	mutex_lock(&resource->resource_lock);
310 	result = acpi_power_off_unlocked(resource);
311 	mutex_unlock(&resource->resource_lock);
312 	return result;
313 }
314 
315 static int acpi_power_off_list(struct list_head *list)
316 {
317 	struct acpi_power_resource_entry *entry;
318 	int result = 0;
319 
320 	list_for_each_entry_reverse(entry, list, node) {
321 		result = acpi_power_off(entry->resource);
322 		if (result)
323 			goto err;
324 	}
325 	return 0;
326 
327  err:
328 	list_for_each_entry_continue(entry, list, node)
329 		acpi_power_on(entry->resource);
330 
331 	return result;
332 }
333 
334 static int acpi_power_on_list(struct list_head *list)
335 {
336 	struct acpi_power_resource_entry *entry;
337 	int result = 0;
338 
339 	list_for_each_entry(entry, list, node) {
340 		result = acpi_power_on(entry->resource);
341 		if (result)
342 			goto err;
343 	}
344 	return 0;
345 
346  err:
347 	list_for_each_entry_continue_reverse(entry, list, node)
348 		acpi_power_off(entry->resource);
349 
350 	return result;
351 }
352 
353 static struct attribute *attrs[] = {
354 	NULL,
355 };
356 
357 static struct attribute_group attr_groups[] = {
358 	[ACPI_STATE_D0] = {
359 		.name = "power_resources_D0",
360 		.attrs = attrs,
361 	},
362 	[ACPI_STATE_D1] = {
363 		.name = "power_resources_D1",
364 		.attrs = attrs,
365 	},
366 	[ACPI_STATE_D2] = {
367 		.name = "power_resources_D2",
368 		.attrs = attrs,
369 	},
370 	[ACPI_STATE_D3_HOT] = {
371 		.name = "power_resources_D3hot",
372 		.attrs = attrs,
373 	},
374 };
375 
376 static struct attribute_group wakeup_attr_group = {
377 	.name = "power_resources_wakeup",
378 	.attrs = attrs,
379 };
380 
381 static void acpi_power_hide_list(struct acpi_device *adev,
382 				 struct list_head *resources,
383 				 struct attribute_group *attr_group)
384 {
385 	struct acpi_power_resource_entry *entry;
386 
387 	if (list_empty(resources))
388 		return;
389 
390 	list_for_each_entry_reverse(entry, resources, node) {
391 		struct acpi_device *res_dev = &entry->resource->device;
392 
393 		sysfs_remove_link_from_group(&adev->dev.kobj,
394 					     attr_group->name,
395 					     dev_name(&res_dev->dev));
396 	}
397 	sysfs_remove_group(&adev->dev.kobj, attr_group);
398 }
399 
400 static void acpi_power_expose_list(struct acpi_device *adev,
401 				   struct list_head *resources,
402 				   struct attribute_group *attr_group)
403 {
404 	struct acpi_power_resource_entry *entry;
405 	int ret;
406 
407 	if (list_empty(resources))
408 		return;
409 
410 	ret = sysfs_create_group(&adev->dev.kobj, attr_group);
411 	if (ret)
412 		return;
413 
414 	list_for_each_entry(entry, resources, node) {
415 		struct acpi_device *res_dev = &entry->resource->device;
416 
417 		ret = sysfs_add_link_to_group(&adev->dev.kobj,
418 					      attr_group->name,
419 					      &res_dev->dev.kobj,
420 					      dev_name(&res_dev->dev));
421 		if (ret) {
422 			acpi_power_hide_list(adev, resources, attr_group);
423 			break;
424 		}
425 	}
426 }
427 
428 static void acpi_power_expose_hide(struct acpi_device *adev,
429 				   struct list_head *resources,
430 				   struct attribute_group *attr_group,
431 				   bool expose)
432 {
433 	if (expose)
434 		acpi_power_expose_list(adev, resources, attr_group);
435 	else
436 		acpi_power_hide_list(adev, resources, attr_group);
437 }
438 
439 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
440 {
441 	int state;
442 
443 	if (adev->wakeup.flags.valid)
444 		acpi_power_expose_hide(adev, &adev->wakeup.resources,
445 				       &wakeup_attr_group, add);
446 
447 	if (!adev->power.flags.power_resources)
448 		return;
449 
450 	for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
451 		acpi_power_expose_hide(adev,
452 				       &adev->power.states[state].resources,
453 				       &attr_groups[state], add);
454 }
455 
456 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
457 {
458 	struct acpi_power_resource_entry *entry;
459 	int system_level = 5;
460 
461 	list_for_each_entry(entry, list, node) {
462 		struct acpi_power_resource *resource = entry->resource;
463 		acpi_handle handle = resource->device.handle;
464 		int result;
465 		int state;
466 
467 		mutex_lock(&resource->resource_lock);
468 
469 		result = acpi_power_get_state(handle, &state);
470 		if (result) {
471 			mutex_unlock(&resource->resource_lock);
472 			return result;
473 		}
474 		if (state == ACPI_POWER_RESOURCE_STATE_ON) {
475 			resource->ref_count++;
476 			resource->wakeup_enabled = true;
477 		}
478 		if (system_level > resource->system_level)
479 			system_level = resource->system_level;
480 
481 		mutex_unlock(&resource->resource_lock);
482 	}
483 	*system_level_p = system_level;
484 	return 0;
485 }
486 
487 /* --------------------------------------------------------------------------
488                              Device Power Management
489    -------------------------------------------------------------------------- */
490 
491 /**
492  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
493  *                          ACPI 3.0) _PSW (Power State Wake)
494  * @dev: Device to handle.
495  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
496  * @sleep_state: Target sleep state of the system.
497  * @dev_state: Target power state of the device.
498  *
499  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
500  * State Wake) for the device, if present.  On failure reset the device's
501  * wakeup.flags.valid flag.
502  *
503  * RETURN VALUE:
504  * 0 if either _DSW or _PSW has been successfully executed
505  * 0 if neither _DSW nor _PSW has been found
506  * -ENODEV if the execution of either _DSW or _PSW has failed
507  */
508 int acpi_device_sleep_wake(struct acpi_device *dev,
509                            int enable, int sleep_state, int dev_state)
510 {
511 	union acpi_object in_arg[3];
512 	struct acpi_object_list arg_list = { 3, in_arg };
513 	acpi_status status = AE_OK;
514 
515 	/*
516 	 * Try to execute _DSW first.
517 	 *
518 	 * Three agruments are needed for the _DSW object:
519 	 * Argument 0: enable/disable the wake capabilities
520 	 * Argument 1: target system state
521 	 * Argument 2: target device state
522 	 * When _DSW object is called to disable the wake capabilities, maybe
523 	 * the first argument is filled. The values of the other two agruments
524 	 * are meaningless.
525 	 */
526 	in_arg[0].type = ACPI_TYPE_INTEGER;
527 	in_arg[0].integer.value = enable;
528 	in_arg[1].type = ACPI_TYPE_INTEGER;
529 	in_arg[1].integer.value = sleep_state;
530 	in_arg[2].type = ACPI_TYPE_INTEGER;
531 	in_arg[2].integer.value = dev_state;
532 	status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
533 	if (ACPI_SUCCESS(status)) {
534 		return 0;
535 	} else if (status != AE_NOT_FOUND) {
536 		printk(KERN_ERR PREFIX "_DSW execution failed\n");
537 		dev->wakeup.flags.valid = 0;
538 		return -ENODEV;
539 	}
540 
541 	/* Execute _PSW */
542 	status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
543 	if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
544 		printk(KERN_ERR PREFIX "_PSW execution failed\n");
545 		dev->wakeup.flags.valid = 0;
546 		return -ENODEV;
547 	}
548 
549 	return 0;
550 }
551 
552 /*
553  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
554  * 1. Power on the power resources required for the wakeup device
555  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
556  *    State Wake) for the device, if present
557  */
558 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
559 {
560 	struct acpi_power_resource_entry *entry;
561 	int err = 0;
562 
563 	if (!dev || !dev->wakeup.flags.valid)
564 		return -EINVAL;
565 
566 	mutex_lock(&acpi_device_lock);
567 
568 	if (dev->wakeup.prepare_count++)
569 		goto out;
570 
571 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
572 		struct acpi_power_resource *resource = entry->resource;
573 
574 		mutex_lock(&resource->resource_lock);
575 
576 		if (!resource->wakeup_enabled) {
577 			err = acpi_power_on_unlocked(resource);
578 			if (!err)
579 				resource->wakeup_enabled = true;
580 		}
581 
582 		mutex_unlock(&resource->resource_lock);
583 
584 		if (err) {
585 			dev_err(&dev->dev,
586 				"Cannot turn wakeup power resources on\n");
587 			dev->wakeup.flags.valid = 0;
588 			goto out;
589 		}
590 	}
591 	/*
592 	 * Passing 3 as the third argument below means the device may be
593 	 * put into arbitrary power state afterward.
594 	 */
595 	err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
596 	if (err)
597 		dev->wakeup.prepare_count = 0;
598 
599  out:
600 	mutex_unlock(&acpi_device_lock);
601 	return err;
602 }
603 
604 /*
605  * Shutdown a wakeup device, counterpart of above method
606  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
607  *    State Wake) for the device, if present
608  * 2. Shutdown down the power resources
609  */
610 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
611 {
612 	struct acpi_power_resource_entry *entry;
613 	int err = 0;
614 
615 	if (!dev || !dev->wakeup.flags.valid)
616 		return -EINVAL;
617 
618 	mutex_lock(&acpi_device_lock);
619 
620 	if (--dev->wakeup.prepare_count > 0)
621 		goto out;
622 
623 	/*
624 	 * Executing the code below even if prepare_count is already zero when
625 	 * the function is called may be useful, for example for initialisation.
626 	 */
627 	if (dev->wakeup.prepare_count < 0)
628 		dev->wakeup.prepare_count = 0;
629 
630 	err = acpi_device_sleep_wake(dev, 0, 0, 0);
631 	if (err)
632 		goto out;
633 
634 	list_for_each_entry(entry, &dev->wakeup.resources, node) {
635 		struct acpi_power_resource *resource = entry->resource;
636 
637 		mutex_lock(&resource->resource_lock);
638 
639 		if (resource->wakeup_enabled) {
640 			err = acpi_power_off_unlocked(resource);
641 			if (!err)
642 				resource->wakeup_enabled = false;
643 		}
644 
645 		mutex_unlock(&resource->resource_lock);
646 
647 		if (err) {
648 			dev_err(&dev->dev,
649 				"Cannot turn wakeup power resources off\n");
650 			dev->wakeup.flags.valid = 0;
651 			break;
652 		}
653 	}
654 
655  out:
656 	mutex_unlock(&acpi_device_lock);
657 	return err;
658 }
659 
660 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
661 {
662 	int result = 0;
663 	int list_state = 0;
664 	int i = 0;
665 
666 	if (!device || !state)
667 		return -EINVAL;
668 
669 	/*
670 	 * We know a device's inferred power state when all the resources
671 	 * required for a given D-state are 'on'.
672 	 */
673 	for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
674 		struct list_head *list = &device->power.states[i].resources;
675 
676 		if (list_empty(list))
677 			continue;
678 
679 		result = acpi_power_get_list_state(list, &list_state);
680 		if (result)
681 			return result;
682 
683 		if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
684 			*state = i;
685 			return 0;
686 		}
687 	}
688 
689 	*state = ACPI_STATE_D3_COLD;
690 	return 0;
691 }
692 
693 int acpi_power_on_resources(struct acpi_device *device, int state)
694 {
695 	if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
696 		return -EINVAL;
697 
698 	return acpi_power_on_list(&device->power.states[state].resources);
699 }
700 
701 int acpi_power_transition(struct acpi_device *device, int state)
702 {
703 	int result = 0;
704 
705 	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
706 		return -EINVAL;
707 
708 	if (device->power.state == state || !device->flags.power_manageable)
709 		return 0;
710 
711 	if ((device->power.state < ACPI_STATE_D0)
712 	    || (device->power.state > ACPI_STATE_D3_COLD))
713 		return -ENODEV;
714 
715 	/* TBD: Resources must be ordered. */
716 
717 	/*
718 	 * First we reference all power resources required in the target list
719 	 * (e.g. so the device doesn't lose power while transitioning).  Then,
720 	 * we dereference all power resources used in the current list.
721 	 */
722 	if (state < ACPI_STATE_D3_COLD)
723 		result = acpi_power_on_list(
724 			&device->power.states[state].resources);
725 
726 	if (!result && device->power.state < ACPI_STATE_D3_COLD)
727 		acpi_power_off_list(
728 			&device->power.states[device->power.state].resources);
729 
730 	/* We shouldn't change the state unless the above operations succeed. */
731 	device->power.state = result ? ACPI_STATE_UNKNOWN : state;
732 
733 	return result;
734 }
735 
736 static void acpi_release_power_resource(struct device *dev)
737 {
738 	struct acpi_device *device = to_acpi_device(dev);
739 	struct acpi_power_resource *resource;
740 
741 	resource = container_of(device, struct acpi_power_resource, device);
742 
743 	mutex_lock(&power_resource_list_lock);
744 	list_del(&resource->list_node);
745 	mutex_unlock(&power_resource_list_lock);
746 
747 	acpi_free_pnp_ids(&device->pnp);
748 	kfree(resource);
749 }
750 
751 static ssize_t acpi_power_in_use_show(struct device *dev,
752 				      struct device_attribute *attr,
753 				      char *buf) {
754 	struct acpi_power_resource *resource;
755 
756 	resource = to_power_resource(to_acpi_device(dev));
757 	return sprintf(buf, "%u\n", !!resource->ref_count);
758 }
759 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
760 
761 static void acpi_power_sysfs_remove(struct acpi_device *device)
762 {
763 	device_remove_file(&device->dev, &dev_attr_resource_in_use);
764 }
765 
766 int acpi_add_power_resource(acpi_handle handle)
767 {
768 	struct acpi_power_resource *resource;
769 	struct acpi_device *device = NULL;
770 	union acpi_object acpi_object;
771 	struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
772 	acpi_status status;
773 	int state, result = -ENODEV;
774 
775 	acpi_bus_get_device(handle, &device);
776 	if (device)
777 		return 0;
778 
779 	resource = kzalloc(sizeof(*resource), GFP_KERNEL);
780 	if (!resource)
781 		return -ENOMEM;
782 
783 	device = &resource->device;
784 	acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
785 				ACPI_STA_DEFAULT);
786 	mutex_init(&resource->resource_lock);
787 	INIT_LIST_HEAD(&resource->list_node);
788 	resource->name = device->pnp.bus_id;
789 	strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
790 	strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
791 	device->power.state = ACPI_STATE_UNKNOWN;
792 
793 	/* Evalute the object to get the system level and resource order. */
794 	status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
795 	if (ACPI_FAILURE(status))
796 		goto err;
797 
798 	resource->system_level = acpi_object.power_resource.system_level;
799 	resource->order = acpi_object.power_resource.resource_order;
800 
801 	result = acpi_power_get_state(handle, &state);
802 	if (result)
803 		goto err;
804 
805 	printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
806 	       acpi_device_bid(device), state ? "on" : "off");
807 
808 	device->flags.match_driver = true;
809 	result = acpi_device_add(device, acpi_release_power_resource);
810 	if (result)
811 		goto err;
812 
813 	if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
814 		device->remove = acpi_power_sysfs_remove;
815 
816 	mutex_lock(&power_resource_list_lock);
817 	list_add(&resource->list_node, &acpi_power_resource_list);
818 	mutex_unlock(&power_resource_list_lock);
819 	acpi_device_add_finalize(device);
820 	return 0;
821 
822  err:
823 	acpi_release_power_resource(&device->dev);
824 	return result;
825 }
826 
827 #ifdef CONFIG_ACPI_SLEEP
828 void acpi_resume_power_resources(void)
829 {
830 	struct acpi_power_resource *resource;
831 
832 	mutex_lock(&power_resource_list_lock);
833 
834 	list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
835 		int result, state;
836 
837 		mutex_lock(&resource->resource_lock);
838 
839 		result = acpi_power_get_state(resource->device.handle, &state);
840 		if (result) {
841 			mutex_unlock(&resource->resource_lock);
842 			continue;
843 		}
844 
845 		if (state == ACPI_POWER_RESOURCE_STATE_OFF
846 		    && resource->ref_count) {
847 			dev_info(&resource->device.dev, "Turning ON\n");
848 			__acpi_power_on(resource);
849 		} else if (state == ACPI_POWER_RESOURCE_STATE_ON
850 		    && !resource->ref_count) {
851 			dev_info(&resource->device.dev, "Turning OFF\n");
852 			__acpi_power_off(resource);
853 		}
854 
855 		mutex_unlock(&resource->resource_lock);
856 	}
857 
858 	mutex_unlock(&power_resource_list_lock);
859 }
860 #endif
861