Version:  2.0.40 2.2.26 2.4.37 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6

Linux/drivers/acpi/power.c

  1 /*
  2  * drivers/acpi/power.c - ACPI Power Resources management.
  3  *
  4  * Copyright (C) 2001 - 2015 Intel Corp.
  5  * Author: Andy Grover <andrew.grover@intel.com>
  6  * Author: Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
  7  * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  8  *
  9  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 10  *
 11  *  This program is free software; you can redistribute it and/or modify
 12  *  it under the terms of the GNU General Public License as published by
 13  *  the Free Software Foundation; either version 2 of the License, or (at
 14  *  your option) any later version.
 15  *
 16  *  This program is distributed in the hope that it will be useful, but
 17  *  WITHOUT ANY WARRANTY; without even the implied warranty of
 18  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 19  *  General Public License for more details.
 20  *
 21  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 22  */
 23 
 24 /*
 25  * ACPI power-managed devices may be controlled in two ways:
 26  * 1. via "Device Specific (D-State) Control"
 27  * 2. via "Power Resource Control".
 28  * The code below deals with ACPI Power Resources control.
 29  * 
 30  * An ACPI "power resource object" represents a software controllable power
 31  * plane, clock plane, or other resource depended on by a device.
 32  *
 33  * A device may rely on multiple power resources, and a power resource
 34  * may be shared by multiple devices.
 35  */
 36 
 37 #include <linux/kernel.h>
 38 #include <linux/module.h>
 39 #include <linux/init.h>
 40 #include <linux/types.h>
 41 #include <linux/slab.h>
 42 #include <linux/pm_runtime.h>
 43 #include <linux/sysfs.h>
 44 #include <linux/acpi.h>
 45 #include "sleep.h"
 46 #include "internal.h"
 47 
 48 #define _COMPONENT                      ACPI_POWER_COMPONENT
 49 ACPI_MODULE_NAME("power");
 50 #define ACPI_POWER_CLASS                "power_resource"
 51 #define ACPI_POWER_DEVICE_NAME          "Power Resource"
 52 #define ACPI_POWER_FILE_INFO            "info"
 53 #define ACPI_POWER_FILE_STATUS          "state"
 54 #define ACPI_POWER_RESOURCE_STATE_OFF   0x00
 55 #define ACPI_POWER_RESOURCE_STATE_ON    0x01
 56 #define ACPI_POWER_RESOURCE_STATE_UNKNOWN 0xFF
 57 
 58 struct acpi_power_resource {
 59         struct acpi_device device;
 60         struct list_head list_node;
 61         char *name;
 62         u32 system_level;
 63         u32 order;
 64         unsigned int ref_count;
 65         bool wakeup_enabled;
 66         struct mutex resource_lock;
 67 };
 68 
 69 struct acpi_power_resource_entry {
 70         struct list_head node;
 71         struct acpi_power_resource *resource;
 72 };
 73 
 74 static LIST_HEAD(acpi_power_resource_list);
 75 static DEFINE_MUTEX(power_resource_list_lock);
 76 
 77 /* --------------------------------------------------------------------------
 78                              Power Resource Management
 79    -------------------------------------------------------------------------- */
 80 
 81 static inline
 82 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
 83 {
 84         return container_of(device, struct acpi_power_resource, device);
 85 }
 86 
 87 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
 88 {
 89         struct acpi_device *device;
 90 
 91         if (acpi_bus_get_device(handle, &device))
 92                 return NULL;
 93 
 94         return to_power_resource(device);
 95 }
 96 
 97 static int acpi_power_resources_list_add(acpi_handle handle,
 98                                          struct list_head *list)
 99 {
100         struct acpi_power_resource *resource = acpi_power_get_context(handle);
101         struct acpi_power_resource_entry *entry;
102 
103         if (!resource || !list)
104                 return -EINVAL;
105 
106         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
107         if (!entry)
108                 return -ENOMEM;
109 
110         entry->resource = resource;
111         if (!list_empty(list)) {
112                 struct acpi_power_resource_entry *e;
113 
114                 list_for_each_entry(e, list, node)
115                         if (e->resource->order > resource->order) {
116                                 list_add_tail(&entry->node, &e->node);
117                                 return 0;
118                         }
119         }
120         list_add_tail(&entry->node, list);
121         return 0;
122 }
123 
124 void acpi_power_resources_list_free(struct list_head *list)
125 {
126         struct acpi_power_resource_entry *entry, *e;
127 
128         list_for_each_entry_safe(entry, e, list, node) {
129                 list_del(&entry->node);
130                 kfree(entry);
131         }
132 }
133 
134 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
135                                  struct list_head *list)
136 {
137         unsigned int i;
138         int err = 0;
139 
140         for (i = start; i < package->package.count; i++) {
141                 union acpi_object *element = &package->package.elements[i];
142                 acpi_handle rhandle;
143 
144                 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
145                         err = -ENODATA;
146                         break;
147                 }
148                 rhandle = element->reference.handle;
149                 if (!rhandle) {
150                         err = -ENODEV;
151                         break;
152                 }
153                 err = acpi_add_power_resource(rhandle);
154                 if (err)
155                         break;
156 
157                 err = acpi_power_resources_list_add(rhandle, list);
158                 if (err)
159                         break;
160         }
161         if (err)
162                 acpi_power_resources_list_free(list);
163 
164         return err;
165 }
166 
167 static int acpi_power_get_state(acpi_handle handle, int *state)
168 {
169         acpi_status status = AE_OK;
170         unsigned long long sta = 0;
171         char node_name[5];
172         struct acpi_buffer buffer = { sizeof(node_name), node_name };
173 
174 
175         if (!handle || !state)
176                 return -EINVAL;
177 
178         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
179         if (ACPI_FAILURE(status))
180                 return -ENODEV;
181 
182         *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
183                               ACPI_POWER_RESOURCE_STATE_OFF;
184 
185         acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
186 
187         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
188                           node_name,
189                                 *state ? "on" : "off"));
190 
191         return 0;
192 }
193 
194 static int acpi_power_get_list_state(struct list_head *list, int *state)
195 {
196         struct acpi_power_resource_entry *entry;
197         int cur_state;
198 
199         if (!list || !state)
200                 return -EINVAL;
201 
202         /* The state of the list is 'on' IFF all resources are 'on'. */
203         list_for_each_entry(entry, list, node) {
204                 struct acpi_power_resource *resource = entry->resource;
205                 acpi_handle handle = resource->device.handle;
206                 int result;
207 
208                 mutex_lock(&resource->resource_lock);
209                 result = acpi_power_get_state(handle, &cur_state);
210                 mutex_unlock(&resource->resource_lock);
211                 if (result)
212                         return result;
213 
214                 if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
215                         break;
216         }
217 
218         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
219                           cur_state ? "on" : "off"));
220 
221         *state = cur_state;
222         return 0;
223 }
224 
225 static int __acpi_power_on(struct acpi_power_resource *resource)
226 {
227         acpi_status status = AE_OK;
228 
229         status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
230         if (ACPI_FAILURE(status))
231                 return -ENODEV;
232 
233         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
234                           resource->name));
235 
236         return 0;
237 }
238 
239 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
240 {
241         int result = 0;
242 
243         if (resource->ref_count++) {
244                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
245                                   "Power resource [%s] already on\n",
246                                   resource->name));
247         } else {
248                 result = __acpi_power_on(resource);
249                 if (result)
250                         resource->ref_count--;
251         }
252         return result;
253 }
254 
255 static int acpi_power_on(struct acpi_power_resource *resource)
256 {
257         int result;
258 
259         mutex_lock(&resource->resource_lock);
260         result = acpi_power_on_unlocked(resource);
261         mutex_unlock(&resource->resource_lock);
262         return result;
263 }
264 
265 static int __acpi_power_off(struct acpi_power_resource *resource)
266 {
267         acpi_status status;
268 
269         status = acpi_evaluate_object(resource->device.handle, "_OFF",
270                                       NULL, NULL);
271         if (ACPI_FAILURE(status))
272                 return -ENODEV;
273 
274         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
275                           resource->name));
276         return 0;
277 }
278 
279 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
280 {
281         int result = 0;
282 
283         if (!resource->ref_count) {
284                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
285                                   "Power resource [%s] already off\n",
286                                   resource->name));
287                 return 0;
288         }
289 
290         if (--resource->ref_count) {
291                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
292                                   "Power resource [%s] still in use\n",
293                                   resource->name));
294         } else {
295                 result = __acpi_power_off(resource);
296                 if (result)
297                         resource->ref_count++;
298         }
299         return result;
300 }
301 
302 static int acpi_power_off(struct acpi_power_resource *resource)
303 {
304         int result;
305 
306         mutex_lock(&resource->resource_lock);
307         result = acpi_power_off_unlocked(resource);
308         mutex_unlock(&resource->resource_lock);
309         return result;
310 }
311 
312 static int acpi_power_off_list(struct list_head *list)
313 {
314         struct acpi_power_resource_entry *entry;
315         int result = 0;
316 
317         list_for_each_entry_reverse(entry, list, node) {
318                 result = acpi_power_off(entry->resource);
319                 if (result)
320                         goto err;
321         }
322         return 0;
323 
324  err:
325         list_for_each_entry_continue(entry, list, node)
326                 acpi_power_on(entry->resource);
327 
328         return result;
329 }
330 
331 static int acpi_power_on_list(struct list_head *list)
332 {
333         struct acpi_power_resource_entry *entry;
334         int result = 0;
335 
336         list_for_each_entry(entry, list, node) {
337                 result = acpi_power_on(entry->resource);
338                 if (result)
339                         goto err;
340         }
341         return 0;
342 
343  err:
344         list_for_each_entry_continue_reverse(entry, list, node)
345                 acpi_power_off(entry->resource);
346 
347         return result;
348 }
349 
350 static struct attribute *attrs[] = {
351         NULL,
352 };
353 
354 static struct attribute_group attr_groups[] = {
355         [ACPI_STATE_D0] = {
356                 .name = "power_resources_D0",
357                 .attrs = attrs,
358         },
359         [ACPI_STATE_D1] = {
360                 .name = "power_resources_D1",
361                 .attrs = attrs,
362         },
363         [ACPI_STATE_D2] = {
364                 .name = "power_resources_D2",
365                 .attrs = attrs,
366         },
367         [ACPI_STATE_D3_HOT] = {
368                 .name = "power_resources_D3hot",
369                 .attrs = attrs,
370         },
371 };
372 
373 static struct attribute_group wakeup_attr_group = {
374         .name = "power_resources_wakeup",
375         .attrs = attrs,
376 };
377 
378 static void acpi_power_hide_list(struct acpi_device *adev,
379                                  struct list_head *resources,
380                                  struct attribute_group *attr_group)
381 {
382         struct acpi_power_resource_entry *entry;
383 
384         if (list_empty(resources))
385                 return;
386 
387         list_for_each_entry_reverse(entry, resources, node) {
388                 struct acpi_device *res_dev = &entry->resource->device;
389 
390                 sysfs_remove_link_from_group(&adev->dev.kobj,
391                                              attr_group->name,
392                                              dev_name(&res_dev->dev));
393         }
394         sysfs_remove_group(&adev->dev.kobj, attr_group);
395 }
396 
397 static void acpi_power_expose_list(struct acpi_device *adev,
398                                    struct list_head *resources,
399                                    struct attribute_group *attr_group)
400 {
401         struct acpi_power_resource_entry *entry;
402         int ret;
403 
404         if (list_empty(resources))
405                 return;
406 
407         ret = sysfs_create_group(&adev->dev.kobj, attr_group);
408         if (ret)
409                 return;
410 
411         list_for_each_entry(entry, resources, node) {
412                 struct acpi_device *res_dev = &entry->resource->device;
413 
414                 ret = sysfs_add_link_to_group(&adev->dev.kobj,
415                                               attr_group->name,
416                                               &res_dev->dev.kobj,
417                                               dev_name(&res_dev->dev));
418                 if (ret) {
419                         acpi_power_hide_list(adev, resources, attr_group);
420                         break;
421                 }
422         }
423 }
424 
425 static void acpi_power_expose_hide(struct acpi_device *adev,
426                                    struct list_head *resources,
427                                    struct attribute_group *attr_group,
428                                    bool expose)
429 {
430         if (expose)
431                 acpi_power_expose_list(adev, resources, attr_group);
432         else
433                 acpi_power_hide_list(adev, resources, attr_group);
434 }
435 
436 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
437 {
438         int state;
439 
440         if (adev->wakeup.flags.valid)
441                 acpi_power_expose_hide(adev, &adev->wakeup.resources,
442                                        &wakeup_attr_group, add);
443 
444         if (!adev->power.flags.power_resources)
445                 return;
446 
447         for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
448                 acpi_power_expose_hide(adev,
449                                        &adev->power.states[state].resources,
450                                        &attr_groups[state], add);
451 }
452 
453 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
454 {
455         struct acpi_power_resource_entry *entry;
456         int system_level = 5;
457 
458         list_for_each_entry(entry, list, node) {
459                 struct acpi_power_resource *resource = entry->resource;
460                 acpi_handle handle = resource->device.handle;
461                 int result;
462                 int state;
463 
464                 mutex_lock(&resource->resource_lock);
465 
466                 result = acpi_power_get_state(handle, &state);
467                 if (result) {
468                         mutex_unlock(&resource->resource_lock);
469                         return result;
470                 }
471                 if (state == ACPI_POWER_RESOURCE_STATE_ON) {
472                         resource->ref_count++;
473                         resource->wakeup_enabled = true;
474                 }
475                 if (system_level > resource->system_level)
476                         system_level = resource->system_level;
477 
478                 mutex_unlock(&resource->resource_lock);
479         }
480         *system_level_p = system_level;
481         return 0;
482 }
483 
484 /* --------------------------------------------------------------------------
485                              Device Power Management
486    -------------------------------------------------------------------------- */
487 
488 /**
489  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
490  *                          ACPI 3.0) _PSW (Power State Wake)
491  * @dev: Device to handle.
492  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
493  * @sleep_state: Target sleep state of the system.
494  * @dev_state: Target power state of the device.
495  *
496  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
497  * State Wake) for the device, if present.  On failure reset the device's
498  * wakeup.flags.valid flag.
499  *
500  * RETURN VALUE:
501  * 0 if either _DSW or _PSW has been successfully executed
502  * 0 if neither _DSW nor _PSW has been found
503  * -ENODEV if the execution of either _DSW or _PSW has failed
504  */
505 int acpi_device_sleep_wake(struct acpi_device *dev,
506                            int enable, int sleep_state, int dev_state)
507 {
508         union acpi_object in_arg[3];
509         struct acpi_object_list arg_list = { 3, in_arg };
510         acpi_status status = AE_OK;
511 
512         /*
513          * Try to execute _DSW first.
514          *
515          * Three agruments are needed for the _DSW object:
516          * Argument 0: enable/disable the wake capabilities
517          * Argument 1: target system state
518          * Argument 2: target device state
519          * When _DSW object is called to disable the wake capabilities, maybe
520          * the first argument is filled. The values of the other two agruments
521          * are meaningless.
522          */
523         in_arg[0].type = ACPI_TYPE_INTEGER;
524         in_arg[0].integer.value = enable;
525         in_arg[1].type = ACPI_TYPE_INTEGER;
526         in_arg[1].integer.value = sleep_state;
527         in_arg[2].type = ACPI_TYPE_INTEGER;
528         in_arg[2].integer.value = dev_state;
529         status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
530         if (ACPI_SUCCESS(status)) {
531                 return 0;
532         } else if (status != AE_NOT_FOUND) {
533                 printk(KERN_ERR PREFIX "_DSW execution failed\n");
534                 dev->wakeup.flags.valid = 0;
535                 return -ENODEV;
536         }
537 
538         /* Execute _PSW */
539         status = acpi_execute_simple_method(dev->handle, "_PSW", enable);
540         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
541                 printk(KERN_ERR PREFIX "_PSW execution failed\n");
542                 dev->wakeup.flags.valid = 0;
543                 return -ENODEV;
544         }
545 
546         return 0;
547 }
548 
549 /*
550  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
551  * 1. Power on the power resources required for the wakeup device 
552  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
553  *    State Wake) for the device, if present
554  */
555 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
556 {
557         struct acpi_power_resource_entry *entry;
558         int err = 0;
559 
560         if (!dev || !dev->wakeup.flags.valid)
561                 return -EINVAL;
562 
563         mutex_lock(&acpi_device_lock);
564 
565         if (dev->wakeup.prepare_count++)
566                 goto out;
567 
568         list_for_each_entry(entry, &dev->wakeup.resources, node) {
569                 struct acpi_power_resource *resource = entry->resource;
570 
571                 mutex_lock(&resource->resource_lock);
572 
573                 if (!resource->wakeup_enabled) {
574                         err = acpi_power_on_unlocked(resource);
575                         if (!err)
576                                 resource->wakeup_enabled = true;
577                 }
578 
579                 mutex_unlock(&resource->resource_lock);
580 
581                 if (err) {
582                         dev_err(&dev->dev,
583                                 "Cannot turn wakeup power resources on\n");
584                         dev->wakeup.flags.valid = 0;
585                         goto out;
586                 }
587         }
588         /*
589          * Passing 3 as the third argument below means the device may be
590          * put into arbitrary power state afterward.
591          */
592         err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
593         if (err)
594                 dev->wakeup.prepare_count = 0;
595 
596  out:
597         mutex_unlock(&acpi_device_lock);
598         return err;
599 }
600 
601 /*
602  * Shutdown a wakeup device, counterpart of above method
603  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
604  *    State Wake) for the device, if present
605  * 2. Shutdown down the power resources
606  */
607 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
608 {
609         struct acpi_power_resource_entry *entry;
610         int err = 0;
611 
612         if (!dev || !dev->wakeup.flags.valid)
613                 return -EINVAL;
614 
615         mutex_lock(&acpi_device_lock);
616 
617         if (--dev->wakeup.prepare_count > 0)
618                 goto out;
619 
620         /*
621          * Executing the code below even if prepare_count is already zero when
622          * the function is called may be useful, for example for initialisation.
623          */
624         if (dev->wakeup.prepare_count < 0)
625                 dev->wakeup.prepare_count = 0;
626 
627         err = acpi_device_sleep_wake(dev, 0, 0, 0);
628         if (err)
629                 goto out;
630 
631         list_for_each_entry(entry, &dev->wakeup.resources, node) {
632                 struct acpi_power_resource *resource = entry->resource;
633 
634                 mutex_lock(&resource->resource_lock);
635 
636                 if (resource->wakeup_enabled) {
637                         err = acpi_power_off_unlocked(resource);
638                         if (!err)
639                                 resource->wakeup_enabled = false;
640                 }
641 
642                 mutex_unlock(&resource->resource_lock);
643 
644                 if (err) {
645                         dev_err(&dev->dev,
646                                 "Cannot turn wakeup power resources off\n");
647                         dev->wakeup.flags.valid = 0;
648                         break;
649                 }
650         }
651 
652  out:
653         mutex_unlock(&acpi_device_lock);
654         return err;
655 }
656 
657 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
658 {
659         int result = 0;
660         int list_state = 0;
661         int i = 0;
662 
663         if (!device || !state)
664                 return -EINVAL;
665 
666         /*
667          * We know a device's inferred power state when all the resources
668          * required for a given D-state are 'on'.
669          */
670         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
671                 struct list_head *list = &device->power.states[i].resources;
672 
673                 if (list_empty(list))
674                         continue;
675 
676                 result = acpi_power_get_list_state(list, &list_state);
677                 if (result)
678                         return result;
679 
680                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
681                         *state = i;
682                         return 0;
683                 }
684         }
685 
686         *state = device->power.states[ACPI_STATE_D3_COLD].flags.valid ?
687                 ACPI_STATE_D3_COLD : ACPI_STATE_D3_HOT;
688         return 0;
689 }
690 
691 int acpi_power_on_resources(struct acpi_device *device, int state)
692 {
693         if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
694                 return -EINVAL;
695 
696         return acpi_power_on_list(&device->power.states[state].resources);
697 }
698 
699 int acpi_power_transition(struct acpi_device *device, int state)
700 {
701         int result = 0;
702 
703         if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
704                 return -EINVAL;
705 
706         if (device->power.state == state || !device->flags.power_manageable)
707                 return 0;
708 
709         if ((device->power.state < ACPI_STATE_D0)
710             || (device->power.state > ACPI_STATE_D3_COLD))
711                 return -ENODEV;
712 
713         /*
714          * First we reference all power resources required in the target list
715          * (e.g. so the device doesn't lose power while transitioning).  Then,
716          * we dereference all power resources used in the current list.
717          */
718         if (state < ACPI_STATE_D3_COLD)
719                 result = acpi_power_on_list(
720                         &device->power.states[state].resources);
721 
722         if (!result && device->power.state < ACPI_STATE_D3_COLD)
723                 acpi_power_off_list(
724                         &device->power.states[device->power.state].resources);
725 
726         /* We shouldn't change the state unless the above operations succeed. */
727         device->power.state = result ? ACPI_STATE_UNKNOWN : state;
728 
729         return result;
730 }
731 
732 static void acpi_release_power_resource(struct device *dev)
733 {
734         struct acpi_device *device = to_acpi_device(dev);
735         struct acpi_power_resource *resource;
736 
737         resource = container_of(device, struct acpi_power_resource, device);
738 
739         mutex_lock(&power_resource_list_lock);
740         list_del(&resource->list_node);
741         mutex_unlock(&power_resource_list_lock);
742 
743         acpi_free_pnp_ids(&device->pnp);
744         kfree(resource);
745 }
746 
747 static ssize_t acpi_power_in_use_show(struct device *dev,
748                                       struct device_attribute *attr,
749                                       char *buf) {
750         struct acpi_power_resource *resource;
751 
752         resource = to_power_resource(to_acpi_device(dev));
753         return sprintf(buf, "%u\n", !!resource->ref_count);
754 }
755 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
756 
757 static void acpi_power_sysfs_remove(struct acpi_device *device)
758 {
759         device_remove_file(&device->dev, &dev_attr_resource_in_use);
760 }
761 
762 static void acpi_power_add_resource_to_list(struct acpi_power_resource *resource)
763 {
764         mutex_lock(&power_resource_list_lock);
765 
766         if (!list_empty(&acpi_power_resource_list)) {
767                 struct acpi_power_resource *r;
768 
769                 list_for_each_entry(r, &acpi_power_resource_list, list_node)
770                         if (r->order > resource->order) {
771                                 list_add_tail(&resource->list_node, &r->list_node);
772                                 goto out;
773                         }
774         }
775         list_add_tail(&resource->list_node, &acpi_power_resource_list);
776 
777  out:
778         mutex_unlock(&power_resource_list_lock);
779 }
780 
781 int acpi_add_power_resource(acpi_handle handle)
782 {
783         struct acpi_power_resource *resource;
784         struct acpi_device *device = NULL;
785         union acpi_object acpi_object;
786         struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
787         acpi_status status;
788         int state, result = -ENODEV;
789 
790         acpi_bus_get_device(handle, &device);
791         if (device)
792                 return 0;
793 
794         resource = kzalloc(sizeof(*resource), GFP_KERNEL);
795         if (!resource)
796                 return -ENOMEM;
797 
798         device = &resource->device;
799         acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
800                                 ACPI_STA_DEFAULT);
801         mutex_init(&resource->resource_lock);
802         INIT_LIST_HEAD(&resource->list_node);
803         resource->name = device->pnp.bus_id;
804         strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
805         strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
806         device->power.state = ACPI_STATE_UNKNOWN;
807 
808         /* Evalute the object to get the system level and resource order. */
809         status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
810         if (ACPI_FAILURE(status))
811                 goto err;
812 
813         resource->system_level = acpi_object.power_resource.system_level;
814         resource->order = acpi_object.power_resource.resource_order;
815 
816         result = acpi_power_get_state(handle, &state);
817         if (result)
818                 goto err;
819 
820         printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
821                acpi_device_bid(device), state ? "on" : "off");
822 
823         device->flags.match_driver = true;
824         result = acpi_device_add(device, acpi_release_power_resource);
825         if (result)
826                 goto err;
827 
828         if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
829                 device->remove = acpi_power_sysfs_remove;
830 
831         acpi_power_add_resource_to_list(resource);
832         acpi_device_add_finalize(device);
833         return 0;
834 
835  err:
836         acpi_release_power_resource(&device->dev);
837         return result;
838 }
839 
840 #ifdef CONFIG_ACPI_SLEEP
841 void acpi_resume_power_resources(void)
842 {
843         struct acpi_power_resource *resource;
844 
845         mutex_lock(&power_resource_list_lock);
846 
847         list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
848                 int result, state;
849 
850                 mutex_lock(&resource->resource_lock);
851 
852                 result = acpi_power_get_state(resource->device.handle, &state);
853                 if (result) {
854                         mutex_unlock(&resource->resource_lock);
855                         continue;
856                 }
857 
858                 if (state == ACPI_POWER_RESOURCE_STATE_OFF
859                     && resource->ref_count) {
860                         dev_info(&resource->device.dev, "Turning ON\n");
861                         __acpi_power_on(resource);
862                 }
863 
864                 mutex_unlock(&resource->resource_lock);
865         }
866         list_for_each_entry_reverse(resource, &acpi_power_resource_list, list_node) {
867                 int result, state;
868 
869                 mutex_lock(&resource->resource_lock);
870 
871                 result = acpi_power_get_state(resource->device.handle, &state);
872                 if (result) {
873                         mutex_unlock(&resource->resource_lock);
874                         continue;
875                 }
876 
877                 if (state == ACPI_POWER_RESOURCE_STATE_ON
878                     && !resource->ref_count) {
879                         dev_info(&resource->device.dev, "Turning OFF\n");
880                         __acpi_power_off(resource);
881                 }
882 
883                 mutex_unlock(&resource->resource_lock);
884         }
885 
886         mutex_unlock(&power_resource_list_lock);
887 }
888 #endif
889 

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