drivers/acpi/acpica/evregion.c

   1 /******************************************************************************
   2  *
   3  * Module Name: evregion - Operation Region support
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2013, Intel Corp.
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include "accommon.h"
  46 #include "acevents.h"
  47 #include "acnamesp.h"
  48 #include "acinterp.h"
  49
  50 #define _COMPONENT          ACPI_EVENTS
  51 ACPI_MODULE_NAME("evregion")
  52
  53 extern u8 acpi_gbl_default_address_spaces[];
  54
  55 /* Local prototypes */
  56
  57 static void
  58 acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node *ec_device_node);
  59
  60 static acpi_status
  61 acpi_ev_reg_run(acpi_handle obj_handle,
  62                 u32 level, void *context, void **return_value);
  63
  64 /*******************************************************************************
  65  *
  66  * FUNCTION:    acpi_ev_initialize_op_regions
  67  *
  68  * PARAMETERS:  None
  69  *
  70  * RETURN:      Status
  71  *
  72  * DESCRIPTION: Execute _REG methods for all Operation Regions that have
  73  *              an installed default region handler.
  74  *
  75  ******************************************************************************/
  76
  77 acpi_status acpi_ev_initialize_op_regions(void)
  78 {
  79         acpi_status status;
  80         u32 i;
  81
  82         ACPI_FUNCTION_TRACE(ev_initialize_op_regions);
  83
  84         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
  85         if (ACPI_FAILURE(status)) {
  86                 return_ACPI_STATUS(status);
  87         }
  88
  89         /* Run the _REG methods for op_regions in each default address space */
  90
  91         for (i = 0; i < ACPI_NUM_DEFAULT_SPACES; i++) {
  92                 /*
  93                  * Make sure the installed handler is the DEFAULT handler. If not the
  94                  * default, the _REG methods will have already been run (when the
  95                  * handler was installed)
  96                  */
  97                 if (acpi_ev_has_default_handler(acpi_gbl_root_node,
  98                                                 acpi_gbl_default_address_spaces
  99                                                 [i])) {
 100                         status =
 101                             acpi_ev_execute_reg_methods(acpi_gbl_root_node,
 102                                                         acpi_gbl_default_address_spaces
 103                                                         [i]);
 104                 }
 105         }
 106
 107         acpi_gbl_reg_methods_executed = TRUE;
 108
 109         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 110         return_ACPI_STATUS(status);
 111 }
 112
 113 /*******************************************************************************
 114  *
 115  * FUNCTION:    acpi_ev_address_space_dispatch
 116  *
 117  * PARAMETERS:  region_obj          - Internal region object
 118  *              field_obj           - Corresponding field. Can be NULL.
 119  *              function            - Read or Write operation
 120  *              region_offset       - Where in the region to read or write
 121  *              bit_width           - Field width in bits (8, 16, 32, or 64)
 122  *              value               - Pointer to in or out value, must be
 123  *                                    a full 64-bit integer
 124  *
 125  * RETURN:      Status
 126  *
 127  * DESCRIPTION: Dispatch an address space or operation region access to
 128  *              a previously installed handler.
 129  *
 130  ******************************************************************************/
 131
 132 acpi_status
 133 acpi_ev_address_space_dispatch(union acpi_operand_object *region_obj,
 134                                union acpi_operand_object *field_obj,
 135                                u32 function,
 136                                u32 region_offset, u32 bit_width, u64 *value)
 137 {
 138         acpi_status status;
 139         acpi_adr_space_handler handler;
 140         acpi_adr_space_setup region_setup;
 141         union acpi_operand_object *handler_desc;
 142         union acpi_operand_object *region_obj2;
 143         void *region_context = NULL;
 144         struct acpi_connection_info *context;
 145
 146         ACPI_FUNCTION_TRACE(ev_address_space_dispatch);
 147
 148         region_obj2 = acpi_ns_get_secondary_object(region_obj);
 149         if (!region_obj2) {
 150                 return_ACPI_STATUS(AE_NOT_EXIST);
 151         }
 152
 153         /* Ensure that there is a handler associated with this region */
 154
 155         handler_desc = region_obj->region.handler;
 156         if (!handler_desc) {
 157                 ACPI_ERROR((AE_INFO,
 158                             "No handler for Region [%4.4s] (%p) [%s]",
 159                             acpi_ut_get_node_name(region_obj->region.node),
 160                             region_obj,
 161                             acpi_ut_get_region_name(region_obj->region.
 162                                                     space_id)));
 163
 164                 return_ACPI_STATUS(AE_NOT_EXIST);
 165         }
 166
 167         context = handler_desc->address_space.context;
 168
 169         /*
 170          * It may be the case that the region has never been initialized.
 171          * Some types of regions require special init code
 172          */
 173         if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE)) {
 174
 175                 /* This region has not been initialized yet, do it */
 176
 177                 region_setup = handler_desc->address_space.setup;
 178                 if (!region_setup) {
 179
 180                         /* No initialization routine, exit with error */
 181
 182                         ACPI_ERROR((AE_INFO,
 183                                     "No init routine for region(%p) [%s]",
 184                                     region_obj,
 185                                     acpi_ut_get_region_name(region_obj->region.
 186                                                             space_id)));
 187                         return_ACPI_STATUS(AE_NOT_EXIST);
 188                 }
 189
 190                 /*
 191                  * We must exit the interpreter because the region setup will
 192                  * potentially execute control methods (for example, the _REG method
 193                  * for this region)
 194                  */
 195                 acpi_ex_exit_interpreter();
 196
 197                 status = region_setup(region_obj, ACPI_REGION_ACTIVATE,
 198                                       context, &region_context);
 199
 200                 /* Re-enter the interpreter */
 201
 202                 acpi_ex_enter_interpreter();
 203
 204                 /* Check for failure of the Region Setup */
 205
 206                 if (ACPI_FAILURE(status)) {
 207                         ACPI_EXCEPTION((AE_INFO, status,
 208                                         "During region initialization: [%s]",
 209                                         acpi_ut_get_region_name(region_obj->
 210                                                                 region.
 211                                                                 space_id)));
 212                         return_ACPI_STATUS(status);
 213                 }
 214
 215                 /* Region initialization may have been completed by region_setup */
 216
 217                 if (!(region_obj->region.flags & AOPOBJ_SETUP_COMPLETE)) {
 218                         region_obj->region.flags |= AOPOBJ_SETUP_COMPLETE;
 219
 220                         /*
 221                          * Save the returned context for use in all accesses to
 222                          * the handler for this particular region
 223                          */
 224                         if (!(region_obj2->extra.region_context)) {
 225                                 region_obj2->extra.region_context =
 226                                     region_context;
 227                         }
 228                 }
 229         }
 230
 231         /* We have everything we need, we can invoke the address space handler */
 232
 233         handler = handler_desc->address_space.handler;
 234
 235         ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
 236                           "Handler %p (@%p) Address %8.8X%8.8X [%s]\n",
 237                           &region_obj->region.handler->address_space, handler,
 238                           ACPI_FORMAT_NATIVE_UINT(region_obj->region.address +
 239                                                   region_offset),
 240                           acpi_ut_get_region_name(region_obj->region.
 241                                                   space_id)));
 242
 243         /*
 244          * Special handling for generic_serial_bus and general_purpose_io:
 245          * There are three extra parameters that must be passed to the
 246          * handler via the context:
 247          *   1) Connection buffer, a resource template from Connection() op.
 248          *   2) Length of the above buffer.
 249          *   3) Actual access length from the access_as() op.
 250          */
 251         if (((region_obj->region.space_id == ACPI_ADR_SPACE_GSBUS) ||
 252              (region_obj->region.space_id == ACPI_ADR_SPACE_GPIO)) &&
 253             context && field_obj) {
 254
 255                 /* Get the Connection (resource_template) buffer */
 256
 257                 context->connection = field_obj->field.resource_buffer;
 258                 context->length = field_obj->field.resource_length;
 259                 context->access_length = field_obj->field.access_length;
 260         }
 261
 262         if (!(handler_desc->address_space.handler_flags &
 263               ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
 264                 /*
 265                  * For handlers other than the default (supplied) handlers, we must
 266                  * exit the interpreter because the handler *might* block -- we don't
 267                  * know what it will do, so we can't hold the lock on the intepreter.
 268                  */
 269                 acpi_ex_exit_interpreter();
 270         }
 271
 272         /* Call the handler */
 273
 274         status = handler(function,
 275                          (region_obj->region.address + region_offset),
 276                          bit_width, value, context,
 277                          region_obj2->extra.region_context);
 278
 279         if (ACPI_FAILURE(status)) {
 280                 ACPI_EXCEPTION((AE_INFO, status, "Returned by Handler for [%s]",
 281                                 acpi_ut_get_region_name(region_obj->region.
 282                                                         space_id)));
 283         }
 284
 285         if (!(handler_desc->address_space.handler_flags &
 286               ACPI_ADDR_HANDLER_DEFAULT_INSTALLED)) {
 287                 /*
 288                  * We just returned from a non-default handler, we must re-enter the
 289                  * interpreter
 290                  */
 291                 acpi_ex_enter_interpreter();
 292         }
 293
 294         return_ACPI_STATUS(status);
 295 }
 296
 297 /*******************************************************************************
 298  *
 299  * FUNCTION:    acpi_ev_detach_region
 300  *
 301  * PARAMETERS:  region_obj          - Region Object
 302  *              acpi_ns_is_locked   - Namespace Region Already Locked?
 303  *
 304  * RETURN:      None
 305  *
 306  * DESCRIPTION: Break the association between the handler and the region
 307  *              this is a two way association.
 308  *
 309  ******************************************************************************/
 310
 311 void
 312 acpi_ev_detach_region(union acpi_operand_object *region_obj,
 313                       u8 acpi_ns_is_locked)
 314 {
 315         union acpi_operand_object *handler_obj;
 316         union acpi_operand_object *obj_desc;
 317         union acpi_operand_object **last_obj_ptr;
 318         acpi_adr_space_setup region_setup;
 319         void **region_context;
 320         union acpi_operand_object *region_obj2;
 321         acpi_status status;
 322
 323         ACPI_FUNCTION_TRACE(ev_detach_region);
 324
 325         region_obj2 = acpi_ns_get_secondary_object(region_obj);
 326         if (!region_obj2) {
 327                 return_VOID;
 328         }
 329         region_context = &region_obj2->extra.region_context;
 330
 331         /* Get the address handler from the region object */
 332
 333         handler_obj = region_obj->region.handler;
 334         if (!handler_obj) {
 335
 336                 /* This region has no handler, all done */
 337
 338                 return_VOID;
 339         }
 340
 341         /* Find this region in the handler's list */
 342
 343         obj_desc = handler_obj->address_space.region_list;
 344         last_obj_ptr = &handler_obj->address_space.region_list;
 345
 346         while (obj_desc) {
 347
 348                 /* Is this the correct Region? */
 349
 350                 if (obj_desc == region_obj) {
 351                         ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
 352                                           "Removing Region %p from address handler %p\n",
 353                                           region_obj, handler_obj));
 354
 355                         /* This is it, remove it from the handler's list */
 356
 357                         *last_obj_ptr = obj_desc->region.next;
 358                         obj_desc->region.next = NULL;   /* Must clear field */
 359
 360                         if (acpi_ns_is_locked) {
 361                                 status =
 362                                     acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 363                                 if (ACPI_FAILURE(status)) {
 364                                         return_VOID;
 365                                 }
 366                         }
 367
 368                         /* Now stop region accesses by executing the _REG method */
 369
 370                         status =
 371                             acpi_ev_execute_reg_method(region_obj,
 372                                                        ACPI_REG_DISCONNECT);
 373                         if (ACPI_FAILURE(status)) {
 374                                 ACPI_EXCEPTION((AE_INFO, status,
 375                                                 "from region _REG, [%s]",
 376                                                 acpi_ut_get_region_name
 377                                                 (region_obj->region.space_id)));
 378                         }
 379
 380                         if (acpi_ns_is_locked) {
 381                                 status =
 382                                     acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 383                                 if (ACPI_FAILURE(status)) {
 384                                         return_VOID;
 385                                 }
 386                         }
 387
 388                         /*
 389                          * If the region has been activated, call the setup handler with
 390                          * the deactivate notification
 391                          */
 392                         if (region_obj->region.flags & AOPOBJ_SETUP_COMPLETE) {
 393                                 region_setup = handler_obj->address_space.setup;
 394                                 status =
 395                                     region_setup(region_obj,
 396                                                  ACPI_REGION_DEACTIVATE,
 397                                                  handler_obj->address_space.
 398                                                  context, region_context);
 399
 400                                 /*
 401                                  * region_context should have been released by the deactivate
 402                                  * operation. We don't need access to it anymore here.
 403                                  */
 404                                 if (region_context) {
 405                                         *region_context = NULL;
 406                                 }
 407
 408                                 /* Init routine may fail, Just ignore errors */
 409
 410                                 if (ACPI_FAILURE(status)) {
 411                                         ACPI_EXCEPTION((AE_INFO, status,
 412                                                         "from region handler - deactivate, [%s]",
 413                                                         acpi_ut_get_region_name
 414                                                         (region_obj->region.
 415                                                          space_id)));
 416                                 }
 417
 418                                 region_obj->region.flags &=
 419                                     ~(AOPOBJ_SETUP_COMPLETE);
 420                         }
 421
 422                         /*
 423                          * Remove handler reference in the region
 424                          *
 425                          * NOTE: this doesn't mean that the region goes away, the region
 426                          * is just inaccessible as indicated to the _REG method
 427                          *
 428                          * If the region is on the handler's list, this must be the
 429                          * region's handler
 430                          */
 431                         region_obj->region.handler = NULL;
 432                         acpi_ut_remove_reference(handler_obj);
 433
 434                         return_VOID;
 435                 }
 436
 437                 /* Walk the linked list of handlers */
 438
 439                 last_obj_ptr = &obj_desc->region.next;
 440                 obj_desc = obj_desc->region.next;
 441         }
 442
 443         /* If we get here, the region was not in the handler's region list */
 444
 445         ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
 446                           "Cannot remove region %p from address handler %p\n",
 447                           region_obj, handler_obj));
 448
 449         return_VOID;
 450 }
 451
 452 /*******************************************************************************
 453  *
 454  * FUNCTION:    acpi_ev_attach_region
 455  *
 456  * PARAMETERS:  handler_obj         - Handler Object
 457  *              region_obj          - Region Object
 458  *              acpi_ns_is_locked   - Namespace Region Already Locked?
 459  *
 460  * RETURN:      None
 461  *
 462  * DESCRIPTION: Create the association between the handler and the region
 463  *              this is a two way association.
 464  *
 465  ******************************************************************************/
 466
 467 acpi_status
 468 acpi_ev_attach_region(union acpi_operand_object *handler_obj,
 469                       union acpi_operand_object *region_obj,
 470                       u8 acpi_ns_is_locked)
 471 {
 472
 473         ACPI_FUNCTION_TRACE(ev_attach_region);
 474
 475         ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
 476                           "Adding Region [%4.4s] %p to address handler %p [%s]\n",
 477                           acpi_ut_get_node_name(region_obj->region.node),
 478                           region_obj, handler_obj,
 479                           acpi_ut_get_region_name(region_obj->region.
 480                                                   space_id)));
 481
 482         /* Link this region to the front of the handler's list */
 483
 484         region_obj->region.next = handler_obj->address_space.region_list;
 485         handler_obj->address_space.region_list = region_obj;
 486
 487         /* Install the region's handler */
 488
 489         if (region_obj->region.handler) {
 490                 return_ACPI_STATUS(AE_ALREADY_EXISTS);
 491         }
 492
 493         region_obj->region.handler = handler_obj;
 494         acpi_ut_add_reference(handler_obj);
 495
 496         return_ACPI_STATUS(AE_OK);
 497 }
 498
 499 /*******************************************************************************
 500  *
 501  * FUNCTION:    acpi_ev_execute_reg_method
 502  *
 503  * PARAMETERS:  region_obj          - Region object
 504  *              function            - Passed to _REG: On (1) or Off (0)
 505  *
 506  * RETURN:      Status
 507  *
 508  * DESCRIPTION: Execute _REG method for a region
 509  *
 510  ******************************************************************************/
 511
 512 acpi_status
 513 acpi_ev_execute_reg_method(union acpi_operand_object *region_obj, u32 function)
 514 {
 515         struct acpi_evaluate_info *info;
 516         union acpi_operand_object *args[3];
 517         union acpi_operand_object *region_obj2;
 518         acpi_status status;
 519
 520         ACPI_FUNCTION_TRACE(ev_execute_reg_method);
 521
 522         region_obj2 = acpi_ns_get_secondary_object(region_obj);
 523         if (!region_obj2) {
 524                 return_ACPI_STATUS(AE_NOT_EXIST);
 525         }
 526
 527         if (region_obj2->extra.method_REG == NULL) {
 528                 return_ACPI_STATUS(AE_OK);
 529         }
 530
 531         /* Allocate and initialize the evaluation information block */
 532
 533         info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 534         if (!info) {
 535                 return_ACPI_STATUS(AE_NO_MEMORY);
 536         }
 537
 538         info->prefix_node = region_obj2->extra.method_REG;
 539         info->relative_pathname = NULL;
 540         info->parameters = args;
 541         info->flags = ACPI_IGNORE_RETURN_VALUE;
 542
 543         /*
 544          * The _REG method has two arguments:
 545          *
 546          * arg0 - Integer:
 547          *  Operation region space ID Same value as region_obj->Region.space_id
 548          *
 549          * arg1 - Integer:
 550          *  connection status 1 for connecting the handler, 0 for disconnecting
 551          *  the handler (Passed as a parameter)
 552          */
 553         args[0] =
 554             acpi_ut_create_integer_object((u64)region_obj->region.space_id);
 555         if (!args[0]) {
 556                 status = AE_NO_MEMORY;
 557                 goto cleanup1;
 558         }
 559
 560         args[1] = acpi_ut_create_integer_object((u64)function);
 561         if (!args[1]) {
 562                 status = AE_NO_MEMORY;
 563                 goto cleanup2;
 564         }
 565
 566         args[2] = NULL;         /* Terminate list */
 567
 568         /* Execute the method, no return value */
 569
 570         ACPI_DEBUG_EXEC(acpi_ut_display_init_pathname
 571                         (ACPI_TYPE_METHOD, info->prefix_node, NULL));
 572
 573         status = acpi_ns_evaluate(info);
 574         acpi_ut_remove_reference(args[1]);
 575
 576       cleanup2:
 577         acpi_ut_remove_reference(args[0]);
 578
 579       cleanup1:
 580         ACPI_FREE(info);
 581         return_ACPI_STATUS(status);
 582 }
 583
 584 /*******************************************************************************
 585  *
 586  * FUNCTION:    acpi_ev_execute_reg_methods
 587  *
 588  * PARAMETERS:  node            - Namespace node for the device
 589  *              space_id        - The address space ID
 590  *
 591  * RETURN:      Status
 592  *
 593  * DESCRIPTION: Run all _REG methods for the input Space ID;
 594  *              Note: assumes namespace is locked, or system init time.
 595  *
 596  ******************************************************************************/
 597
 598 acpi_status
 599 acpi_ev_execute_reg_methods(struct acpi_namespace_node *node,
 600                             acpi_adr_space_type space_id)
 601 {
 602         acpi_status status;
 603
 604         ACPI_FUNCTION_TRACE(ev_execute_reg_methods);
 605
 606         /*
 607          * Run all _REG methods for all Operation Regions for this space ID. This
 608          * is a separate walk in order to handle any interdependencies between
 609          * regions and _REG methods. (i.e. handlers must be installed for all
 610          * regions of this Space ID before we can run any _REG methods)
 611          */
 612         status = acpi_ns_walk_namespace(ACPI_TYPE_ANY, node, ACPI_UINT32_MAX,
 613                                         ACPI_NS_WALK_UNLOCK, acpi_ev_reg_run,
 614                                         NULL, &space_id, NULL);
 615
 616         /* Special case for EC: handle "orphan" _REG methods with no region */
 617
 618         if (space_id == ACPI_ADR_SPACE_EC) {
 619                 acpi_ev_orphan_ec_reg_method(node);
 620         }
 621
 622         return_ACPI_STATUS(status);
 623 }
 624
 625 /*******************************************************************************
 626  *
 627  * FUNCTION:    acpi_ev_reg_run
 628  *
 629  * PARAMETERS:  walk_namespace callback
 630  *
 631  * DESCRIPTION: Run _REG method for region objects of the requested spaceID
 632  *
 633  ******************************************************************************/
 634
 635 static acpi_status
 636 acpi_ev_reg_run(acpi_handle obj_handle,
 637                 u32 level, void *context, void **return_value)
 638 {
 639         union acpi_operand_object *obj_desc;
 640         struct acpi_namespace_node *node;
 641         acpi_adr_space_type space_id;
 642         acpi_status status;
 643
 644         space_id = *ACPI_CAST_PTR(acpi_adr_space_type, context);
 645
 646         /* Convert and validate the device handle */
 647
 648         node = acpi_ns_validate_handle(obj_handle);
 649         if (!node) {
 650                 return (AE_BAD_PARAMETER);
 651         }
 652
 653         /*
 654          * We only care about regions.and objects that are allowed to have address
 655          * space handlers
 656          */
 657         if ((node->type != ACPI_TYPE_REGION) && (node != acpi_gbl_root_node)) {
 658                 return (AE_OK);
 659         }
 660
 661         /* Check for an existing internal object */
 662
 663         obj_desc = acpi_ns_get_attached_object(node);
 664         if (!obj_desc) {
 665
 666                 /* No object, just exit */
 667
 668                 return (AE_OK);
 669         }
 670
 671         /* Object is a Region */
 672
 673         if (obj_desc->region.space_id != space_id) {
 674
 675                 /* This region is for a different address space, just ignore it */
 676
 677                 return (AE_OK);
 678         }
 679
 680         status = acpi_ev_execute_reg_method(obj_desc, ACPI_REG_CONNECT);
 681         return (status);
 682 }
 683
 684 /*******************************************************************************
 685  *
 686  * FUNCTION:    acpi_ev_orphan_ec_reg_method
 687  *
 688  * PARAMETERS:  ec_device_node      - Namespace node for an EC device
 689  *
 690  * RETURN:      None
 691  *
 692  * DESCRIPTION: Execute an "orphan" _REG method that appears under the EC
 693  *              device. This is a _REG method that has no corresponding region
 694  *              within the EC device scope. The orphan _REG method appears to
 695  *              have been enabled by the description of the ECDT in the ACPI
 696  *              specification: "The availability of the region space can be
 697  *              detected by providing a _REG method object underneath the
 698  *              Embedded Controller device."
 699  *
 700  *              To quickly access the EC device, we use the ec_device_node used
 701  *              during EC handler installation. Otherwise, we would need to
 702  *              perform a time consuming namespace walk, executing _HID
 703  *              methods to find the EC device.
 704  *
 705  *  MUTEX:      Assumes the namespace is locked
 706  *
 707  ******************************************************************************/
 708
 709 static void
 710 acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node *ec_device_node)
 711 {
 712         acpi_handle reg_method;
 713         struct acpi_namespace_node *next_node;
 714         acpi_status status;
 715         struct acpi_object_list args;
 716         union acpi_object objects[2];
 717
 718         ACPI_FUNCTION_TRACE(ev_orphan_ec_reg_method);
 719
 720         if (!ec_device_node) {
 721                 return_VOID;
 722         }
 723
 724         /* Namespace is currently locked, must release */
 725
 726         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 727
 728         /* Get a handle to a _REG method immediately under the EC device */
 729
 730         status = acpi_get_handle(ec_device_node, METHOD_NAME__REG, &reg_method);
 731         if (ACPI_FAILURE(status)) {
 732                 goto exit;      /* There is no _REG method present */
 733         }
 734
 735         /*
 736          * Execute the _REG method only if there is no Operation Region in
 737          * this scope with the Embedded Controller space ID. Otherwise, it
 738          * will already have been executed. Note, this allows for Regions
 739          * with other space IDs to be present; but the code below will then
 740          * execute the _REG method with the embedded_control space_ID argument.
 741          */
 742         next_node = acpi_ns_get_next_node(ec_device_node, NULL);
 743         while (next_node) {
 744                 if ((next_node->type == ACPI_TYPE_REGION) &&
 745                     (next_node->object) &&
 746                     (next_node->object->region.space_id == ACPI_ADR_SPACE_EC)) {
 747                         goto exit;      /* Do not execute the _REG */
 748                 }
 749
 750                 next_node = acpi_ns_get_next_node(ec_device_node, next_node);
 751         }
 752
 753         /* Evaluate the _REG(embedded_control,Connect) method */
 754
 755         args.count = 2;
 756         args.pointer = objects;
 757         objects[0].type = ACPI_TYPE_INTEGER;
 758         objects[0].integer.value = ACPI_ADR_SPACE_EC;
 759         objects[1].type = ACPI_TYPE_INTEGER;
 760         objects[1].integer.value = ACPI_REG_CONNECT;
 761
 762         status = acpi_evaluate_object(reg_method, NULL, &args, NULL);
 763
 764       exit:
 765         /* We ignore all errors from above, don't care */
 766
 767         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 768         return_VOID;
 769 }