drivers/acpi/power.c

   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_dependent_device {
  63         struct list_head node;
  64         struct acpi_device *adev;
  65         struct work_struct work;
  66 };
  67
  68 struct acpi_power_resource {
  69         struct acpi_device device;
  70         struct list_head list_node;
  71         struct list_head dependent;
  72         char *name;
  73         u32 system_level;
  74         u32 order;
  75         unsigned int ref_count;
  76         bool wakeup_enabled;
  77         struct mutex resource_lock;
  78 };
  79
  80 struct acpi_power_resource_entry {
  81         struct list_head node;
  82         struct acpi_power_resource *resource;
  83 };
  84
  85 static LIST_HEAD(acpi_power_resource_list);
  86 static DEFINE_MUTEX(power_resource_list_lock);
  87
  88 /* --------------------------------------------------------------------------
  89                              Power Resource Management
  90    -------------------------------------------------------------------------- */
  91
  92 static inline
  93 struct acpi_power_resource *to_power_resource(struct acpi_device *device)
  94 {
  95         return container_of(device, struct acpi_power_resource, device);
  96 }
  97
  98 static struct acpi_power_resource *acpi_power_get_context(acpi_handle handle)
  99 {
 100         struct acpi_device *device;
 101
 102         if (acpi_bus_get_device(handle, &device))
 103                 return NULL;
 104
 105         return to_power_resource(device);
 106 }
 107
 108 static int acpi_power_resources_list_add(acpi_handle handle,
 109                                          struct list_head *list)
 110 {
 111         struct acpi_power_resource *resource = acpi_power_get_context(handle);
 112         struct acpi_power_resource_entry *entry;
 113
 114         if (!resource || !list)
 115                 return -EINVAL;
 116
 117         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 118         if (!entry)
 119                 return -ENOMEM;
 120
 121         entry->resource = resource;
 122         if (!list_empty(list)) {
 123                 struct acpi_power_resource_entry *e;
 124
 125                 list_for_each_entry(e, list, node)
 126                         if (e->resource->order > resource->order) {
 127                                 list_add_tail(&entry->node, &e->node);
 128                                 return 0;
 129                         }
 130         }
 131         list_add_tail(&entry->node, list);
 132         return 0;
 133 }
 134
 135 void acpi_power_resources_list_free(struct list_head *list)
 136 {
 137         struct acpi_power_resource_entry *entry, *e;
 138
 139         list_for_each_entry_safe(entry, e, list, node) {
 140                 list_del(&entry->node);
 141                 kfree(entry);
 142         }
 143 }
 144
 145 int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
 146                                  struct list_head *list)
 147 {
 148         unsigned int i;
 149         int err = 0;
 150
 151         for (i = start; i < package->package.count; i++) {
 152                 union acpi_object *element = &package->package.elements[i];
 153                 acpi_handle rhandle;
 154
 155                 if (element->type != ACPI_TYPE_LOCAL_REFERENCE) {
 156                         err = -ENODATA;
 157                         break;
 158                 }
 159                 rhandle = element->reference.handle;
 160                 if (!rhandle) {
 161                         err = -ENODEV;
 162                         break;
 163                 }
 164                 err = acpi_add_power_resource(rhandle);
 165                 if (err)
 166                         break;
 167
 168                 err = acpi_power_resources_list_add(rhandle, list);
 169                 if (err)
 170                         break;
 171         }
 172         if (err)
 173                 acpi_power_resources_list_free(list);
 174
 175         return err;
 176 }
 177
 178 static int acpi_power_get_state(acpi_handle handle, int *state)
 179 {
 180         acpi_status status = AE_OK;
 181         unsigned long long sta = 0;
 182         char node_name[5];
 183         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 184
 185
 186         if (!handle || !state)
 187                 return -EINVAL;
 188
 189         status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
 190         if (ACPI_FAILURE(status))
 191                 return -ENODEV;
 192
 193         *state = (sta & 0x01)?ACPI_POWER_RESOURCE_STATE_ON:
 194                               ACPI_POWER_RESOURCE_STATE_OFF;
 195
 196         acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 197
 198         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource [%s] is %s\n",
 199                           node_name,
 200                                 *state ? "on" : "off"));
 201
 202         return 0;
 203 }
 204
 205 static int acpi_power_get_list_state(struct list_head *list, int *state)
 206 {
 207         struct acpi_power_resource_entry *entry;
 208         int cur_state;
 209
 210         if (!list || !state)
 211                 return -EINVAL;
 212
 213         /* The state of the list is 'on' IFF all resources are 'on'. */
 214         list_for_each_entry(entry, list, node) {
 215                 struct acpi_power_resource *resource = entry->resource;
 216                 acpi_handle handle = resource->device.handle;
 217                 int result;
 218
 219                 mutex_lock(&resource->resource_lock);
 220                 result = acpi_power_get_state(handle, &cur_state);
 221                 mutex_unlock(&resource->resource_lock);
 222                 if (result)
 223                         return result;
 224
 225                 if (cur_state != ACPI_POWER_RESOURCE_STATE_ON)
 226                         break;
 227         }
 228
 229         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Resource list is %s\n",
 230                           cur_state ? "on" : "off"));
 231
 232         *state = cur_state;
 233         return 0;
 234 }
 235
 236 static void acpi_power_resume_dependent(struct work_struct *work)
 237 {
 238         struct acpi_power_dependent_device *dep;
 239         struct acpi_device_physical_node *pn;
 240         struct acpi_device *adev;
 241         int state;
 242
 243         dep = container_of(work, struct acpi_power_dependent_device, work);
 244         adev = dep->adev;
 245         if (acpi_power_get_inferred_state(adev, &state))
 246                 return;
 247
 248         if (state > ACPI_STATE_D0)
 249                 return;
 250
 251         mutex_lock(&adev->physical_node_lock);
 252
 253         list_for_each_entry(pn, &adev->physical_node_list, node)
 254                 pm_request_resume(pn->dev);
 255
 256         list_for_each_entry(pn, &adev->power_dependent, node)
 257                 pm_request_resume(pn->dev);
 258
 259         mutex_unlock(&adev->physical_node_lock);
 260 }
 261
 262 static int __acpi_power_on(struct acpi_power_resource *resource)
 263 {
 264         acpi_status status = AE_OK;
 265
 266         status = acpi_evaluate_object(resource->device.handle, "_ON", NULL, NULL);
 267         if (ACPI_FAILURE(status))
 268                 return -ENODEV;
 269
 270         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned on\n",
 271                           resource->name));
 272
 273         return 0;
 274 }
 275
 276 static int acpi_power_on_unlocked(struct acpi_power_resource *resource)
 277 {
 278         int result = 0;
 279
 280         if (resource->ref_count++) {
 281                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 282                                   "Power resource [%s] already on",
 283                                   resource->name));
 284         } else {
 285                 result = __acpi_power_on(resource);
 286                 if (result) {
 287                         resource->ref_count--;
 288                 } else {
 289                         struct acpi_power_dependent_device *dep;
 290
 291                         list_for_each_entry(dep, &resource->dependent, node)
 292                                 schedule_work(&dep->work);
 293                 }
 294         }
 295         return result;
 296 }
 297
 298 static int acpi_power_on(struct acpi_power_resource *resource)
 299 {
 300         int result;
 301
 302         mutex_lock(&resource->resource_lock);
 303         result = acpi_power_on_unlocked(resource);
 304         mutex_unlock(&resource->resource_lock);
 305         return result;
 306 }
 307
 308 static int __acpi_power_off(struct acpi_power_resource *resource)
 309 {
 310         acpi_status status;
 311
 312         status = acpi_evaluate_object(resource->device.handle, "_OFF",
 313                                       NULL, NULL);
 314         if (ACPI_FAILURE(status))
 315                 return -ENODEV;
 316
 317         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Power resource [%s] turned off\n",
 318                           resource->name));
 319         return 0;
 320 }
 321
 322 static int acpi_power_off_unlocked(struct acpi_power_resource *resource)
 323 {
 324         int result = 0;
 325
 326         if (!resource->ref_count) {
 327                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 328                                   "Power resource [%s] already off",
 329                                   resource->name));
 330                 return 0;
 331         }
 332
 333         if (--resource->ref_count) {
 334                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 335                                   "Power resource [%s] still in use\n",
 336                                   resource->name));
 337         } else {
 338                 result = __acpi_power_off(resource);
 339                 if (result)
 340                         resource->ref_count++;
 341         }
 342         return result;
 343 }
 344
 345 static int acpi_power_off(struct acpi_power_resource *resource)
 346 {
 347         int result;
 348
 349         mutex_lock(&resource->resource_lock);
 350         result = acpi_power_off_unlocked(resource);
 351         mutex_unlock(&resource->resource_lock);
 352         return result;
 353 }
 354
 355 static int acpi_power_off_list(struct list_head *list)
 356 {
 357         struct acpi_power_resource_entry *entry;
 358         int result = 0;
 359
 360         list_for_each_entry_reverse(entry, list, node) {
 361                 result = acpi_power_off(entry->resource);
 362                 if (result)
 363                         goto err;
 364         }
 365         return 0;
 366
 367  err:
 368         list_for_each_entry_continue(entry, list, node)
 369                 acpi_power_on(entry->resource);
 370
 371         return result;
 372 }
 373
 374 static int acpi_power_on_list(struct list_head *list)
 375 {
 376         struct acpi_power_resource_entry *entry;
 377         int result = 0;
 378
 379         list_for_each_entry(entry, list, node) {
 380                 result = acpi_power_on(entry->resource);
 381                 if (result)
 382                         goto err;
 383         }
 384         return 0;
 385
 386  err:
 387         list_for_each_entry_continue_reverse(entry, list, node)
 388                 acpi_power_off(entry->resource);
 389
 390         return result;
 391 }
 392
 393 static void acpi_power_add_dependent(struct acpi_power_resource *resource,
 394                                      struct acpi_device *adev)
 395 {
 396         struct acpi_power_dependent_device *dep;
 397
 398         mutex_lock(&resource->resource_lock);
 399
 400         list_for_each_entry(dep, &resource->dependent, node)
 401                 if (dep->adev == adev)
 402                         goto out;
 403
 404         dep = kzalloc(sizeof(*dep), GFP_KERNEL);
 405         if (!dep)
 406                 goto out;
 407
 408         dep->adev = adev;
 409         INIT_WORK(&dep->work, acpi_power_resume_dependent);
 410         list_add_tail(&dep->node, &resource->dependent);
 411
 412  out:
 413         mutex_unlock(&resource->resource_lock);
 414 }
 415
 416 static void acpi_power_remove_dependent(struct acpi_power_resource *resource,
 417                                         struct acpi_device *adev)
 418 {
 419         struct acpi_power_dependent_device *dep;
 420         struct work_struct *work = NULL;
 421
 422         mutex_lock(&resource->resource_lock);
 423
 424         list_for_each_entry(dep, &resource->dependent, node)
 425                 if (dep->adev == adev) {
 426                         list_del(&dep->node);
 427                         work = &dep->work;
 428                         break;
 429                 }
 430
 431         mutex_unlock(&resource->resource_lock);
 432
 433         if (work) {
 434                 cancel_work_sync(work);
 435                 kfree(dep);
 436         }
 437 }
 438
 439 static struct attribute *attrs[] = {
 440         NULL,
 441 };
 442
 443 static struct attribute_group attr_groups[] = {
 444         [ACPI_STATE_D0] = {
 445                 .name = "power_resources_D0",
 446                 .attrs = attrs,
 447         },
 448         [ACPI_STATE_D1] = {
 449                 .name = "power_resources_D1",
 450                 .attrs = attrs,
 451         },
 452         [ACPI_STATE_D2] = {
 453                 .name = "power_resources_D2",
 454                 .attrs = attrs,
 455         },
 456         [ACPI_STATE_D3_HOT] = {
 457                 .name = "power_resources_D3hot",
 458                 .attrs = attrs,
 459         },
 460 };
 461
 462 static struct attribute_group wakeup_attr_group = {
 463         .name = "power_resources_wakeup",
 464         .attrs = attrs,
 465 };
 466
 467 static void acpi_power_hide_list(struct acpi_device *adev,
 468                                  struct list_head *resources,
 469                                  struct attribute_group *attr_group)
 470 {
 471         struct acpi_power_resource_entry *entry;
 472
 473         if (list_empty(resources))
 474                 return;
 475
 476         list_for_each_entry_reverse(entry, resources, node) {
 477                 struct acpi_device *res_dev = &entry->resource->device;
 478
 479                 sysfs_remove_link_from_group(&adev->dev.kobj,
 480                                              attr_group->name,
 481                                              dev_name(&res_dev->dev));
 482         }
 483         sysfs_remove_group(&adev->dev.kobj, attr_group);
 484 }
 485
 486 static void acpi_power_expose_list(struct acpi_device *adev,
 487                                    struct list_head *resources,
 488                                    struct attribute_group *attr_group)
 489 {
 490         struct acpi_power_resource_entry *entry;
 491         int ret;
 492
 493         if (list_empty(resources))
 494                 return;
 495
 496         ret = sysfs_create_group(&adev->dev.kobj, attr_group);
 497         if (ret)
 498                 return;
 499
 500         list_for_each_entry(entry, resources, node) {
 501                 struct acpi_device *res_dev = &entry->resource->device;
 502
 503                 ret = sysfs_add_link_to_group(&adev->dev.kobj,
 504                                               attr_group->name,
 505                                               &res_dev->dev.kobj,
 506                                               dev_name(&res_dev->dev));
 507                 if (ret) {
 508                         acpi_power_hide_list(adev, resources, attr_group);
 509                         break;
 510                 }
 511         }
 512 }
 513
 514 static void acpi_power_expose_hide(struct acpi_device *adev,
 515                                    struct list_head *resources,
 516                                    struct attribute_group *attr_group,
 517                                    bool expose)
 518 {
 519         if (expose)
 520                 acpi_power_expose_list(adev, resources, attr_group);
 521         else
 522                 acpi_power_hide_list(adev, resources, attr_group);
 523 }
 524
 525 void acpi_power_add_remove_device(struct acpi_device *adev, bool add)
 526 {
 527         struct acpi_device_power_state *ps;
 528         struct acpi_power_resource_entry *entry;
 529         int state;
 530
 531         if (adev->wakeup.flags.valid)
 532                 acpi_power_expose_hide(adev, &adev->wakeup.resources,
 533                                        &wakeup_attr_group, add);
 534
 535         if (!adev->power.flags.power_resources)
 536                 return;
 537
 538         ps = &adev->power.states[ACPI_STATE_D0];
 539         list_for_each_entry(entry, &ps->resources, node) {
 540                 struct acpi_power_resource *resource = entry->resource;
 541
 542                 if (add)
 543                         acpi_power_add_dependent(resource, adev);
 544                 else
 545                         acpi_power_remove_dependent(resource, adev);
 546         }
 547
 548         for (state = ACPI_STATE_D0; state <= ACPI_STATE_D3_HOT; state++)
 549                 acpi_power_expose_hide(adev,
 550                                        &adev->power.states[state].resources,
 551                                        &attr_groups[state], add);
 552 }
 553
 554 int acpi_power_wakeup_list_init(struct list_head *list, int *system_level_p)
 555 {
 556         struct acpi_power_resource_entry *entry;
 557         int system_level = 5;
 558
 559         list_for_each_entry(entry, list, node) {
 560                 struct acpi_power_resource *resource = entry->resource;
 561                 acpi_handle handle = resource->device.handle;
 562                 int result;
 563                 int state;
 564
 565                 mutex_lock(&resource->resource_lock);
 566
 567                 result = acpi_power_get_state(handle, &state);
 568                 if (result) {
 569                         mutex_unlock(&resource->resource_lock);
 570                         return result;
 571                 }
 572                 if (state == ACPI_POWER_RESOURCE_STATE_ON) {
 573                         resource->ref_count++;
 574                         resource->wakeup_enabled = true;
 575                 }
 576                 if (system_level > resource->system_level)
 577                         system_level = resource->system_level;
 578
 579                 mutex_unlock(&resource->resource_lock);
 580         }
 581         *system_level_p = system_level;
 582         return 0;
 583 }
 584
 585 /* --------------------------------------------------------------------------
 586                              Device Power Management
 587    -------------------------------------------------------------------------- */
 588
 589 /**
 590  * acpi_device_sleep_wake - execute _DSW (Device Sleep Wake) or (deprecated in
 591  *                          ACPI 3.0) _PSW (Power State Wake)
 592  * @dev: Device to handle.
 593  * @enable: 0 - disable, 1 - enable the wake capabilities of the device.
 594  * @sleep_state: Target sleep state of the system.
 595  * @dev_state: Target power state of the device.
 596  *
 597  * Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 598  * State Wake) for the device, if present.  On failure reset the device's
 599  * wakeup.flags.valid flag.
 600  *
 601  * RETURN VALUE:
 602  * 0 if either _DSW or _PSW has been successfully executed
 603  * 0 if neither _DSW nor _PSW has been found
 604  * -ENODEV if the execution of either _DSW or _PSW has failed
 605  */
 606 int acpi_device_sleep_wake(struct acpi_device *dev,
 607                            int enable, int sleep_state, int dev_state)
 608 {
 609         union acpi_object in_arg[3];
 610         struct acpi_object_list arg_list = { 3, in_arg };
 611         acpi_status status = AE_OK;
 612
 613         /*
 614          * Try to execute _DSW first.
 615          *
 616          * Three agruments are needed for the _DSW object:
 617          * Argument 0: enable/disable the wake capabilities
 618          * Argument 1: target system state
 619          * Argument 2: target device state
 620          * When _DSW object is called to disable the wake capabilities, maybe
 621          * the first argument is filled. The values of the other two agruments
 622          * are meaningless.
 623          */
 624         in_arg[0].type = ACPI_TYPE_INTEGER;
 625         in_arg[0].integer.value = enable;
 626         in_arg[1].type = ACPI_TYPE_INTEGER;
 627         in_arg[1].integer.value = sleep_state;
 628         in_arg[2].type = ACPI_TYPE_INTEGER;
 629         in_arg[2].integer.value = dev_state;
 630         status = acpi_evaluate_object(dev->handle, "_DSW", &arg_list, NULL);
 631         if (ACPI_SUCCESS(status)) {
 632                 return 0;
 633         } else if (status != AE_NOT_FOUND) {
 634                 printk(KERN_ERR PREFIX "_DSW execution failed\n");
 635                 dev->wakeup.flags.valid = 0;
 636                 return -ENODEV;
 637         }
 638
 639         /* Execute _PSW */
 640         arg_list.count = 1;
 641         in_arg[0].integer.value = enable;
 642         status = acpi_evaluate_object(dev->handle, "_PSW", &arg_list, NULL);
 643         if (ACPI_FAILURE(status) && (status != AE_NOT_FOUND)) {
 644                 printk(KERN_ERR PREFIX "_PSW execution failed\n");
 645                 dev->wakeup.flags.valid = 0;
 646                 return -ENODEV;
 647         }
 648
 649         return 0;
 650 }
 651
 652 /*
 653  * Prepare a wakeup device, two steps (Ref ACPI 2.0:P229):
 654  * 1. Power on the power resources required for the wakeup device
 655  * 2. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 656  *    State Wake) for the device, if present
 657  */
 658 int acpi_enable_wakeup_device_power(struct acpi_device *dev, int sleep_state)
 659 {
 660         struct acpi_power_resource_entry *entry;
 661         int err = 0;
 662
 663         if (!dev || !dev->wakeup.flags.valid)
 664                 return -EINVAL;
 665
 666         mutex_lock(&acpi_device_lock);
 667
 668         if (dev->wakeup.prepare_count++)
 669                 goto out;
 670
 671         list_for_each_entry(entry, &dev->wakeup.resources, node) {
 672                 struct acpi_power_resource *resource = entry->resource;
 673
 674                 mutex_lock(&resource->resource_lock);
 675
 676                 if (!resource->wakeup_enabled) {
 677                         err = acpi_power_on_unlocked(resource);
 678                         if (!err)
 679                                 resource->wakeup_enabled = true;
 680                 }
 681
 682                 mutex_unlock(&resource->resource_lock);
 683
 684                 if (err) {
 685                         dev_err(&dev->dev,
 686                                 "Cannot turn wakeup power resources on\n");
 687                         dev->wakeup.flags.valid = 0;
 688                         goto out;
 689                 }
 690         }
 691         /*
 692          * Passing 3 as the third argument below means the device may be
 693          * put into arbitrary power state afterward.
 694          */
 695         err = acpi_device_sleep_wake(dev, 1, sleep_state, 3);
 696         if (err)
 697                 dev->wakeup.prepare_count = 0;
 698
 699  out:
 700         mutex_unlock(&acpi_device_lock);
 701         return err;
 702 }
 703
 704 /*
 705  * Shutdown a wakeup device, counterpart of above method
 706  * 1. Execute _DSW (Device Sleep Wake) or (deprecated in ACPI 3.0) _PSW (Power
 707  *    State Wake) for the device, if present
 708  * 2. Shutdown down the power resources
 709  */
 710 int acpi_disable_wakeup_device_power(struct acpi_device *dev)
 711 {
 712         struct acpi_power_resource_entry *entry;
 713         int err = 0;
 714
 715         if (!dev || !dev->wakeup.flags.valid)
 716                 return -EINVAL;
 717
 718         mutex_lock(&acpi_device_lock);
 719
 720         if (--dev->wakeup.prepare_count > 0)
 721                 goto out;
 722
 723         /*
 724          * Executing the code below even if prepare_count is already zero when
 725          * the function is called may be useful, for example for initialisation.
 726          */
 727         if (dev->wakeup.prepare_count < 0)
 728                 dev->wakeup.prepare_count = 0;
 729
 730         err = acpi_device_sleep_wake(dev, 0, 0, 0);
 731         if (err)
 732                 goto out;
 733
 734         list_for_each_entry(entry, &dev->wakeup.resources, node) {
 735                 struct acpi_power_resource *resource = entry->resource;
 736
 737                 mutex_lock(&resource->resource_lock);
 738
 739                 if (resource->wakeup_enabled) {
 740                         err = acpi_power_off_unlocked(resource);
 741                         if (!err)
 742                                 resource->wakeup_enabled = false;
 743                 }
 744
 745                 mutex_unlock(&resource->resource_lock);
 746
 747                 if (err) {
 748                         dev_err(&dev->dev,
 749                                 "Cannot turn wakeup power resources off\n");
 750                         dev->wakeup.flags.valid = 0;
 751                         break;
 752                 }
 753         }
 754
 755  out:
 756         mutex_unlock(&acpi_device_lock);
 757         return err;
 758 }
 759
 760 int acpi_power_get_inferred_state(struct acpi_device *device, int *state)
 761 {
 762         int result = 0;
 763         int list_state = 0;
 764         int i = 0;
 765
 766         if (!device || !state)
 767                 return -EINVAL;
 768
 769         /*
 770          * We know a device's inferred power state when all the resources
 771          * required for a given D-state are 'on'.
 772          */
 773         for (i = ACPI_STATE_D0; i <= ACPI_STATE_D3_HOT; i++) {
 774                 struct list_head *list = &device->power.states[i].resources;
 775
 776                 if (list_empty(list))
 777                         continue;
 778
 779                 result = acpi_power_get_list_state(list, &list_state);
 780                 if (result)
 781                         return result;
 782
 783                 if (list_state == ACPI_POWER_RESOURCE_STATE_ON) {
 784                         *state = i;
 785                         return 0;
 786                 }
 787         }
 788
 789         *state = ACPI_STATE_D3;
 790         return 0;
 791 }
 792
 793 int acpi_power_on_resources(struct acpi_device *device, int state)
 794 {
 795         if (!device || state < ACPI_STATE_D0 || state > ACPI_STATE_D3_HOT)
 796                 return -EINVAL;
 797
 798         return acpi_power_on_list(&device->power.states[state].resources);
 799 }
 800
 801 int acpi_power_transition(struct acpi_device *device, int state)
 802 {
 803         int result = 0;
 804
 805         if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 806                 return -EINVAL;
 807
 808         if (device->power.state == state || !device->flags.power_manageable)
 809                 return 0;
 810
 811         if ((device->power.state < ACPI_STATE_D0)
 812             || (device->power.state > ACPI_STATE_D3_COLD))
 813                 return -ENODEV;
 814
 815         /* TBD: Resources must be ordered. */
 816
 817         /*
 818          * First we reference all power resources required in the target list
 819          * (e.g. so the device doesn't lose power while transitioning).  Then,
 820          * we dereference all power resources used in the current list.
 821          */
 822         if (state < ACPI_STATE_D3_COLD)
 823                 result = acpi_power_on_list(
 824                         &device->power.states[state].resources);
 825
 826         if (!result && device->power.state < ACPI_STATE_D3_COLD)
 827                 acpi_power_off_list(
 828                         &device->power.states[device->power.state].resources);
 829
 830         /* We shouldn't change the state unless the above operations succeed. */
 831         device->power.state = result ? ACPI_STATE_UNKNOWN : state;
 832
 833         return result;
 834 }
 835
 836 static void acpi_release_power_resource(struct device *dev)
 837 {
 838         struct acpi_device *device = to_acpi_device(dev);
 839         struct acpi_power_resource *resource;
 840
 841         resource = container_of(device, struct acpi_power_resource, device);
 842
 843         mutex_lock(&power_resource_list_lock);
 844         list_del(&resource->list_node);
 845         mutex_unlock(&power_resource_list_lock);
 846
 847         acpi_free_pnp_ids(&device->pnp);
 848         kfree(resource);
 849 }
 850
 851 static ssize_t acpi_power_in_use_show(struct device *dev,
 852                                       struct device_attribute *attr,
 853                                       char *buf) {
 854         struct acpi_power_resource *resource;
 855
 856         resource = to_power_resource(to_acpi_device(dev));
 857         return sprintf(buf, "%u\n", !!resource->ref_count);
 858 }
 859 static DEVICE_ATTR(resource_in_use, 0444, acpi_power_in_use_show, NULL);
 860
 861 static void acpi_power_sysfs_remove(struct acpi_device *device)
 862 {
 863         device_remove_file(&device->dev, &dev_attr_resource_in_use);
 864 }
 865
 866 int acpi_add_power_resource(acpi_handle handle)
 867 {
 868         struct acpi_power_resource *resource;
 869         struct acpi_device *device = NULL;
 870         union acpi_object acpi_object;
 871         struct acpi_buffer buffer = { sizeof(acpi_object), &acpi_object };
 872         acpi_status status;
 873         int state, result = -ENODEV;
 874
 875         acpi_bus_get_device(handle, &device);
 876         if (device)
 877                 return 0;
 878
 879         resource = kzalloc(sizeof(*resource), GFP_KERNEL);
 880         if (!resource)
 881                 return -ENOMEM;
 882
 883         device = &resource->device;
 884         acpi_init_device_object(device, handle, ACPI_BUS_TYPE_POWER,
 885                                 ACPI_STA_DEFAULT);
 886         mutex_init(&resource->resource_lock);
 887         INIT_LIST_HEAD(&resource->dependent);
 888         resource->name = device->pnp.bus_id;
 889         strcpy(acpi_device_name(device), ACPI_POWER_DEVICE_NAME);
 890         strcpy(acpi_device_class(device), ACPI_POWER_CLASS);
 891         device->power.state = ACPI_STATE_UNKNOWN;
 892
 893         /* Evalute the object to get the system level and resource order. */
 894         status = acpi_evaluate_object(handle, NULL, NULL, &buffer);
 895         if (ACPI_FAILURE(status))
 896                 goto err;
 897
 898         resource->system_level = acpi_object.power_resource.system_level;
 899         resource->order = acpi_object.power_resource.resource_order;
 900
 901         result = acpi_power_get_state(handle, &state);
 902         if (result)
 903                 goto err;
 904
 905         printk(KERN_INFO PREFIX "%s [%s] (%s)\n", acpi_device_name(device),
 906                acpi_device_bid(device), state ? "on" : "off");
 907
 908         device->flags.match_driver = true;
 909         result = acpi_device_add(device, acpi_release_power_resource);
 910         if (result)
 911                 goto err;
 912
 913         if (!device_create_file(&device->dev, &dev_attr_resource_in_use))
 914                 device->remove = acpi_power_sysfs_remove;
 915
 916         mutex_lock(&power_resource_list_lock);
 917         list_add(&resource->list_node, &acpi_power_resource_list);
 918         mutex_unlock(&power_resource_list_lock);
 919         acpi_device_add_finalize(device);
 920         return 0;
 921
 922  err:
 923         acpi_release_power_resource(&device->dev);
 924         return result;
 925 }
 926
 927 #ifdef CONFIG_ACPI_SLEEP
 928 void acpi_resume_power_resources(void)
 929 {
 930         struct acpi_power_resource *resource;
 931
 932         mutex_lock(&power_resource_list_lock);
 933
 934         list_for_each_entry(resource, &acpi_power_resource_list, list_node) {
 935                 int result, state;
 936
 937                 mutex_lock(&resource->resource_lock);
 938
 939                 result = acpi_power_get_state(resource->device.handle, &state);
 940                 if (result)
 941                         continue;
 942
 943                 if (state == ACPI_POWER_RESOURCE_STATE_OFF
 944                     && resource->ref_count) {
 945                         dev_info(&resource->device.dev, "Turning ON\n");
 946                         __acpi_power_on(resource);
 947                 } else if (state == ACPI_POWER_RESOURCE_STATE_ON
 948                     && !resource->ref_count) {
 949                         dev_info(&resource->device.dev, "Turning OFF\n");
 950                         __acpi_power_off(resource);
 951                 }
 952
 953                 mutex_unlock(&resource->resource_lock);
 954         }
 955
 956         mutex_unlock(&power_resource_list_lock);
 957 }
 958 #endif