Pileus Git - ~andy/linux/blob - drivers/acpi/acpica/nsxfeval.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nsxfeval - Public interfaces to the ACPI subsystem
   4  *                         ACPI Object evaluation interfaces
   5  *
   6  ******************************************************************************/
   7
   8 /*
   9  * Copyright (C) 2000 - 2013, Intel Corp.
  10  * All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions, and the following disclaimer,
  17  *    without modification.
  18  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  19  *    substantially similar to the "NO WARRANTY" disclaimer below
  20  *    ("Disclaimer") and any redistribution must be conditioned upon
  21  *    including a substantially similar Disclaimer requirement for further
  22  *    binary redistribution.
  23  * 3. Neither the names of the above-listed copyright holders nor the names
  24  *    of any contributors may be used to endorse or promote products derived
  25  *    from this software without specific prior written permission.
  26  *
  27  * Alternatively, this software may be distributed under the terms of the
  28  * GNU General Public License ("GPL") version 2 as published by the Free
  29  * Software Foundation.
  30  *
  31  * NO WARRANTY
  32  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  33  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  34  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  35  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  36  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  37  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  38  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  39  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  40  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  41  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  42  * POSSIBILITY OF SUCH DAMAGES.
  43  */
  44
  45 #define EXPORT_ACPI_INTERFACES
  46
  47 #include <acpi/acpi.h>
  48 #include "accommon.h"
  49 #include "acnamesp.h"
  50 #include "acinterp.h"
  51
  52 #define _COMPONENT          ACPI_NAMESPACE
  53 ACPI_MODULE_NAME("nsxfeval")
  54
  55 /* Local prototypes */
  56 static void acpi_ns_resolve_references(struct acpi_evaluate_info *info);
  57
  58 /*******************************************************************************
  59  *
  60  * FUNCTION:    acpi_evaluate_object_typed
  61  *
  62  * PARAMETERS:  handle              - Object handle (optional)
  63  *              pathname            - Object pathname (optional)
  64  *              external_params     - List of parameters to pass to method,
  65  *                                    terminated by NULL. May be NULL
  66  *                                    if no parameters are being passed.
  67  *              return_buffer       - Where to put method's return value (if
  68  *                                    any). If NULL, no value is returned.
  69  *              return_type         - Expected type of return object
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Find and evaluate the given object, passing the given
  74  *              parameters if necessary. One of "Handle" or "Pathname" must
  75  *              be valid (non-null)
  76  *
  77  ******************************************************************************/
  78
  79 acpi_status
  80 acpi_evaluate_object_typed(acpi_handle handle,
  81                            acpi_string pathname,
  82                            struct acpi_object_list *external_params,
  83                            struct acpi_buffer *return_buffer,
  84                            acpi_object_type return_type)
  85 {
  86         acpi_status status;
  87         u8 must_free = FALSE;
  88
  89         ACPI_FUNCTION_TRACE(acpi_evaluate_object_typed);
  90
  91         /* Return buffer must be valid */
  92
  93         if (!return_buffer) {
  94                 return_ACPI_STATUS(AE_BAD_PARAMETER);
  95         }
  96
  97         if (return_buffer->length == ACPI_ALLOCATE_BUFFER) {
  98                 must_free = TRUE;
  99         }
 100
 101         /* Evaluate the object */
 102
 103         status =
 104             acpi_evaluate_object(handle, pathname, external_params,
 105                                  return_buffer);
 106         if (ACPI_FAILURE(status)) {
 107                 return_ACPI_STATUS(status);
 108         }
 109
 110         /* Type ANY means "don't care" */
 111
 112         if (return_type == ACPI_TYPE_ANY) {
 113                 return_ACPI_STATUS(AE_OK);
 114         }
 115
 116         if (return_buffer->length == 0) {
 117
 118                 /* Error because caller specifically asked for a return value */
 119
 120                 ACPI_ERROR((AE_INFO, "No return value"));
 121                 return_ACPI_STATUS(AE_NULL_OBJECT);
 122         }
 123
 124         /* Examine the object type returned from evaluate_object */
 125
 126         if (((union acpi_object *)return_buffer->pointer)->type == return_type) {
 127                 return_ACPI_STATUS(AE_OK);
 128         }
 129
 130         /* Return object type does not match requested type */
 131
 132         ACPI_ERROR((AE_INFO,
 133                     "Incorrect return type [%s] requested [%s]",
 134                     acpi_ut_get_type_name(((union acpi_object *)return_buffer->
 135                                            pointer)->type),
 136                     acpi_ut_get_type_name(return_type)));
 137
 138         if (must_free) {
 139
 140                 /* Caller used ACPI_ALLOCATE_BUFFER, free the return buffer */
 141
 142                 ACPI_FREE_BUFFER(*return_buffer);
 143                 return_buffer->pointer = NULL;
 144         }
 145
 146         return_buffer->length = 0;
 147         return_ACPI_STATUS(AE_TYPE);
 148 }
 149
 150 ACPI_EXPORT_SYMBOL(acpi_evaluate_object_typed)
 151
 152 /*******************************************************************************
 153  *
 154  * FUNCTION:    acpi_evaluate_object
 155  *
 156  * PARAMETERS:  handle              - Object handle (optional)
 157  *              pathname            - Object pathname (optional)
 158  *              external_params     - List of parameters to pass to method,
 159  *                                    terminated by NULL. May be NULL
 160  *                                    if no parameters are being passed.
 161  *              return_buffer       - Where to put method's return value (if
 162  *                                    any). If NULL, no value is returned.
 163  *
 164  * RETURN:      Status
 165  *
 166  * DESCRIPTION: Find and evaluate the given object, passing the given
 167  *              parameters if necessary. One of "Handle" or "Pathname" must
 168  *              be valid (non-null)
 169  *
 170  ******************************************************************************/
 171 acpi_status
 172 acpi_evaluate_object(acpi_handle handle,
 173                      acpi_string pathname,
 174                      struct acpi_object_list *external_params,
 175                      struct acpi_buffer *return_buffer)
 176 {
 177         acpi_status status;
 178         struct acpi_evaluate_info *info;
 179         acpi_size buffer_space_needed;
 180         u32 i;
 181
 182         ACPI_FUNCTION_TRACE(acpi_evaluate_object);
 183
 184         /* Allocate and initialize the evaluation information block */
 185
 186         info = ACPI_ALLOCATE_ZEROED(sizeof(struct acpi_evaluate_info));
 187         if (!info) {
 188                 return_ACPI_STATUS(AE_NO_MEMORY);
 189         }
 190
 191         /* Convert and validate the device handle */
 192
 193         info->prefix_node = acpi_ns_validate_handle(handle);
 194         if (!info->prefix_node) {
 195                 status = AE_BAD_PARAMETER;
 196                 goto cleanup;
 197         }
 198
 199         /*
 200          * Get the actual namespace node for the target object.
 201          * Handles these cases:
 202          *
 203          * 1) Null node, valid pathname from root (absolute path)
 204          * 2) Node and valid pathname (path relative to Node)
 205          * 3) Node, Null pathname
 206          */
 207         if ((pathname) && (ACPI_IS_ROOT_PREFIX(pathname[0]))) {
 208
 209                 /* The path is fully qualified, just evaluate by name */
 210
 211                 info->prefix_node = NULL;
 212         } else if (!handle) {
 213                 /*
 214                  * A handle is optional iff a fully qualified pathname is specified.
 215                  * Since we've already handled fully qualified names above, this is
 216                  * an error.
 217                  */
 218                 if (!pathname) {
 219                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 220                                           "Both Handle and Pathname are NULL"));
 221                 } else {
 222                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 223                                           "Null Handle with relative pathname [%s]",
 224                                           pathname));
 225                 }
 226
 227                 status = AE_BAD_PARAMETER;
 228                 goto cleanup;
 229         }
 230
 231         info->relative_pathname = pathname;
 232
 233         /*
 234          * Convert all external objects passed as arguments to the
 235          * internal version(s).
 236          */
 237         if (external_params && external_params->count) {
 238                 info->param_count = (u16)external_params->count;
 239
 240                 /* Warn on impossible argument count */
 241
 242                 if (info->param_count > ACPI_METHOD_NUM_ARGS) {
 243                         ACPI_WARN_PREDEFINED((AE_INFO, pathname,
 244                                               ACPI_WARN_ALWAYS,
 245                                               "Excess arguments (%u) - using only %u",
 246                                               info->param_count,
 247                                               ACPI_METHOD_NUM_ARGS));
 248
 249                         info->param_count = ACPI_METHOD_NUM_ARGS;
 250                 }
 251
 252                 /*
 253                  * Allocate a new parameter block for the internal objects
 254                  * Add 1 to count to allow for null terminated internal list
 255                  */
 256                 info->parameters = ACPI_ALLOCATE_ZEROED(((acpi_size) info->
 257                                                          param_count +
 258                                                          1) * sizeof(void *));
 259                 if (!info->parameters) {
 260                         status = AE_NO_MEMORY;
 261                         goto cleanup;
 262                 }
 263
 264                 /* Convert each external object in the list to an internal object */
 265
 266                 for (i = 0; i < info->param_count; i++) {
 267                         status =
 268                             acpi_ut_copy_eobject_to_iobject(&external_params->
 269                                                             pointer[i],
 270                                                             &info->
 271                                                             parameters[i]);
 272                         if (ACPI_FAILURE(status)) {
 273                                 goto cleanup;
 274                         }
 275                 }
 276
 277                 info->parameters[info->param_count] = NULL;
 278         }
 279
 280 #if 0
 281
 282         /*
 283          * Begin incoming argument count analysis. Check for too few args
 284          * and too many args.
 285          */
 286
 287         switch (acpi_ns_get_type(info->node)) {
 288         case ACPI_TYPE_METHOD:
 289
 290                 /* Check incoming argument count against the method definition */
 291
 292                 if (info->obj_desc->method.param_count > info->param_count) {
 293                         ACPI_ERROR((AE_INFO,
 294                                     "Insufficient arguments (%u) - %u are required",
 295                                     info->param_count,
 296                                     info->obj_desc->method.param_count));
 297
 298                         status = AE_MISSING_ARGUMENTS;
 299                         goto cleanup;
 300                 }
 301
 302                 else if (info->obj_desc->method.param_count < info->param_count) {
 303                         ACPI_WARNING((AE_INFO,
 304                                       "Excess arguments (%u) - only %u are required",
 305                                       info->param_count,
 306                                       info->obj_desc->method.param_count));
 307
 308                         /* Just pass the required number of arguments */
 309
 310                         info->param_count = info->obj_desc->method.param_count;
 311                 }
 312
 313                 /*
 314                  * Any incoming external objects to be passed as arguments to the
 315                  * method must be converted to internal objects
 316                  */
 317                 if (info->param_count) {
 318                         /*
 319                          * Allocate a new parameter block for the internal objects
 320                          * Add 1 to count to allow for null terminated internal list
 321                          */
 322                         info->parameters = ACPI_ALLOCATE_ZEROED(((acpi_size)
 323                                                                  info->
 324                                                                  param_count +
 325                                                                  1) *
 326                                                                 sizeof(void *));
 327                         if (!info->parameters) {
 328                                 status = AE_NO_MEMORY;
 329                                 goto cleanup;
 330                         }
 331
 332                         /* Convert each external object in the list to an internal object */
 333
 334                         for (i = 0; i < info->param_count; i++) {
 335                                 status =
 336                                     acpi_ut_copy_eobject_to_iobject
 337                                     (&external_params->pointer[i],
 338                                      &info->parameters[i]);
 339                                 if (ACPI_FAILURE(status)) {
 340                                         goto cleanup;
 341                                 }
 342                         }
 343
 344                         info->parameters[info->param_count] = NULL;
 345                 }
 346                 break;
 347
 348         default:
 349
 350                 /* Warn if arguments passed to an object that is not a method */
 351
 352                 if (info->param_count) {
 353                         ACPI_WARNING((AE_INFO,
 354                                       "%u arguments were passed to a non-method ACPI object",
 355                                       info->param_count));
 356                 }
 357                 break;
 358         }
 359
 360 #endif
 361
 362         /* Now we can evaluate the object */
 363
 364         status = acpi_ns_evaluate(info);
 365
 366         /*
 367          * If we are expecting a return value, and all went well above,
 368          * copy the return value to an external object.
 369          */
 370         if (return_buffer) {
 371                 if (!info->return_object) {
 372                         return_buffer->length = 0;
 373                 } else {
 374                         if (ACPI_GET_DESCRIPTOR_TYPE(info->return_object) ==
 375                             ACPI_DESC_TYPE_NAMED) {
 376                                 /*
 377                                  * If we received a NS Node as a return object, this means that
 378                                  * the object we are evaluating has nothing interesting to
 379                                  * return (such as a mutex, etc.)  We return an error because
 380                                  * these types are essentially unsupported by this interface.
 381                                  * We don't check up front because this makes it easier to add
 382                                  * support for various types at a later date if necessary.
 383                                  */
 384                                 status = AE_TYPE;
 385                                 info->return_object = NULL;     /* No need to delete a NS Node */
 386                                 return_buffer->length = 0;
 387                         }
 388
 389                         if (ACPI_SUCCESS(status)) {
 390
 391                                 /* Dereference Index and ref_of references */
 392
 393                                 acpi_ns_resolve_references(info);
 394
 395                                 /* Get the size of the returned object */
 396
 397                                 status =
 398                                     acpi_ut_get_object_size(info->return_object,
 399                                                             &buffer_space_needed);
 400                                 if (ACPI_SUCCESS(status)) {
 401
 402                                         /* Validate/Allocate/Clear caller buffer */
 403
 404                                         status =
 405                                             acpi_ut_initialize_buffer
 406                                             (return_buffer,
 407                                              buffer_space_needed);
 408                                         if (ACPI_FAILURE(status)) {
 409                                                 /*
 410                                                  * Caller's buffer is too small or a new one can't
 411                                                  * be allocated
 412                                                  */
 413                                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 414                                                                   "Needed buffer size %X, %s\n",
 415                                                                   (u32)
 416                                                                   buffer_space_needed,
 417                                                                   acpi_format_exception
 418                                                                   (status)));
 419                                         } else {
 420                                                 /* We have enough space for the object, build it */
 421
 422                                                 status =
 423                                                     acpi_ut_copy_iobject_to_eobject
 424                                                     (info->return_object,
 425                                                      return_buffer);
 426                                         }
 427                                 }
 428                         }
 429                 }
 430         }
 431
 432         if (info->return_object) {
 433                 /*
 434                  * Delete the internal return object. NOTE: Interpreter must be
 435                  * locked to avoid race condition.
 436                  */
 437                 acpi_ex_enter_interpreter();
 438
 439                 /* Remove one reference on the return object (should delete it) */
 440
 441                 acpi_ut_remove_reference(info->return_object);
 442                 acpi_ex_exit_interpreter();
 443         }
 444
 445 cleanup:
 446
 447         /* Free the input parameter list (if we created one) */
 448
 449         if (info->parameters) {
 450
 451                 /* Free the allocated parameter block */
 452
 453                 acpi_ut_delete_internal_object_list(info->parameters);
 454         }
 455
 456         ACPI_FREE(info);
 457         return_ACPI_STATUS(status);
 458 }
 459
 460 ACPI_EXPORT_SYMBOL(acpi_evaluate_object)
 461
 462 /*******************************************************************************
 463  *
 464  * FUNCTION:    acpi_ns_resolve_references
 465  *
 466  * PARAMETERS:  info                    - Evaluation info block
 467  *
 468  * RETURN:      Info->return_object is replaced with the dereferenced object
 469  *
 470  * DESCRIPTION: Dereference certain reference objects. Called before an
 471  *              internal return object is converted to an external union acpi_object.
 472  *
 473  * Performs an automatic dereference of Index and ref_of reference objects.
 474  * These reference objects are not supported by the union acpi_object, so this is a
 475  * last resort effort to return something useful. Also, provides compatibility
 476  * with other ACPI implementations.
 477  *
 478  * NOTE: does not handle references within returned package objects or nested
 479  * references, but this support could be added later if found to be necessary.
 480  *
 481  ******************************************************************************/
 482 static void acpi_ns_resolve_references(struct acpi_evaluate_info *info)
 483 {
 484         union acpi_operand_object *obj_desc = NULL;
 485         struct acpi_namespace_node *node;
 486
 487         /* We are interested in reference objects only */
 488
 489         if ((info->return_object)->common.type != ACPI_TYPE_LOCAL_REFERENCE) {
 490                 return;
 491         }
 492
 493         /*
 494          * Two types of references are supported - those created by Index and
 495          * ref_of operators. A name reference (AML_NAMEPATH_OP) can be converted
 496          * to an union acpi_object, so it is not dereferenced here. A ddb_handle
 497          * (AML_LOAD_OP) cannot be dereferenced, nor can it be converted to
 498          * an union acpi_object.
 499          */
 500         switch (info->return_object->reference.class) {
 501         case ACPI_REFCLASS_INDEX:
 502
 503                 obj_desc = *(info->return_object->reference.where);
 504                 break;
 505
 506         case ACPI_REFCLASS_REFOF:
 507
 508                 node = info->return_object->reference.object;
 509                 if (node) {
 510                         obj_desc = node->object;
 511                 }
 512                 break;
 513
 514         default:
 515
 516                 return;
 517         }
 518
 519         /* Replace the existing reference object */
 520
 521         if (obj_desc) {
 522                 acpi_ut_add_reference(obj_desc);
 523                 acpi_ut_remove_reference(info->return_object);
 524                 info->return_object = obj_desc;
 525         }
 526
 527         return;
 528 }
 529
 530 /*******************************************************************************
 531  *
 532  * FUNCTION:    acpi_walk_namespace
 533  *
 534  * PARAMETERS:  type                - acpi_object_type to search for
 535  *              start_object        - Handle in namespace where search begins
 536  *              max_depth           - Depth to which search is to reach
 537  *              descending_callback - Called during tree descent
 538  *                                    when an object of "Type" is found
 539  *              ascending_callback  - Called during tree ascent
 540  *                                    when an object of "Type" is found
 541  *              context             - Passed to user function(s) above
 542  *              return_value        - Location where return value of
 543  *                                    user_function is put if terminated early
 544  *
 545  * RETURNS      Return value from the user_function if terminated early.
 546  *              Otherwise, returns NULL.
 547  *
 548  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 549  *              starting (and ending) at the object specified by start_handle.
 550  *              The callback function is called whenever an object that matches
 551  *              the type parameter is found. If the callback function returns
 552  *              a non-zero value, the search is terminated immediately and this
 553  *              value is returned to the caller.
 554  *
 555  *              The point of this procedure is to provide a generic namespace
 556  *              walk routine that can be called from multiple places to
 557  *              provide multiple services; the callback function(s) can be
 558  *              tailored to each task, whether it is a print function,
 559  *              a compare function, etc.
 560  *
 561  ******************************************************************************/
 562
 563 acpi_status
 564 acpi_walk_namespace(acpi_object_type type,
 565                     acpi_handle start_object,
 566                     u32 max_depth,
 567                     acpi_walk_callback descending_callback,
 568                     acpi_walk_callback ascending_callback,
 569                     void *context, void **return_value)
 570 {
 571         acpi_status status;
 572
 573         ACPI_FUNCTION_TRACE(acpi_walk_namespace);
 574
 575         /* Parameter validation */
 576
 577         if ((type > ACPI_TYPE_LOCAL_MAX) ||
 578             (!max_depth) || (!descending_callback && !ascending_callback)) {
 579                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 580         }
 581
 582         /*
 583          * Need to acquire the namespace reader lock to prevent interference
 584          * with any concurrent table unloads (which causes the deletion of
 585          * namespace objects). We cannot allow the deletion of a namespace node
 586          * while the user function is using it. The exception to this are the
 587          * nodes created and deleted during control method execution -- these
 588          * nodes are marked as temporary nodes and are ignored by the namespace
 589          * walk. Thus, control methods can be executed while holding the
 590          * namespace deletion lock (and the user function can execute control
 591          * methods.)
 592          */
 593         status = acpi_ut_acquire_read_lock(&acpi_gbl_namespace_rw_lock);
 594         if (ACPI_FAILURE(status)) {
 595                 return_ACPI_STATUS(status);
 596         }
 597
 598         /*
 599          * Lock the namespace around the walk. The namespace will be
 600          * unlocked/locked around each call to the user function - since the user
 601          * function must be allowed to make ACPICA calls itself (for example, it
 602          * will typically execute control methods during device enumeration.)
 603          */
 604         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 605         if (ACPI_FAILURE(status)) {
 606                 goto unlock_and_exit;
 607         }
 608
 609         /* Now we can validate the starting node */
 610
 611         if (!acpi_ns_validate_handle(start_object)) {
 612                 status = AE_BAD_PARAMETER;
 613                 goto unlock_and_exit2;
 614         }
 615
 616         status = acpi_ns_walk_namespace(type, start_object, max_depth,
 617                                         ACPI_NS_WALK_UNLOCK,
 618                                         descending_callback, ascending_callback,
 619                                         context, return_value);
 620
 621 unlock_and_exit2:
 622         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 623
 624 unlock_and_exit:
 625         (void)acpi_ut_release_read_lock(&acpi_gbl_namespace_rw_lock);
 626         return_ACPI_STATUS(status);
 627 }
 628
 629 ACPI_EXPORT_SYMBOL(acpi_walk_namespace)
 630
 631 /*******************************************************************************
 632  *
 633  * FUNCTION:    acpi_ns_get_device_callback
 634  *
 635  * PARAMETERS:  Callback from acpi_get_device
 636  *
 637  * RETURN:      Status
 638  *
 639  * DESCRIPTION: Takes callbacks from walk_namespace and filters out all non-
 640  *              present devices, or if they specified a HID, it filters based
 641  *              on that.
 642  *
 643  ******************************************************************************/
 644 static acpi_status
 645 acpi_ns_get_device_callback(acpi_handle obj_handle,
 646                             u32 nesting_level,
 647                             void *context, void **return_value)
 648 {
 649         struct acpi_get_devices_info *info = context;
 650         acpi_status status;
 651         struct acpi_namespace_node *node;
 652         u32 flags;
 653         struct acpi_pnp_device_id *hid;
 654         struct acpi_pnp_device_id_list *cid;
 655         u32 i;
 656         u8 found;
 657         int no_match;
 658
 659         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 660         if (ACPI_FAILURE(status)) {
 661                 return (status);
 662         }
 663
 664         node = acpi_ns_validate_handle(obj_handle);
 665         status = acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 666         if (ACPI_FAILURE(status)) {
 667                 return (status);
 668         }
 669
 670         if (!node) {
 671                 return (AE_BAD_PARAMETER);
 672         }
 673
 674         /*
 675          * First, filter based on the device HID and CID.
 676          *
 677          * 01/2010: For this case where a specific HID is requested, we don't
 678          * want to run _STA until we have an actual HID match. Thus, we will
 679          * not unnecessarily execute _STA on devices for which the caller
 680          * doesn't care about. Previously, _STA was executed unconditionally
 681          * on all devices found here.
 682          *
 683          * A side-effect of this change is that now we will continue to search
 684          * for a matching HID even under device trees where the parent device
 685          * would have returned a _STA that indicates it is not present or
 686          * not functioning (thus aborting the search on that branch).
 687          */
 688         if (info->hid != NULL) {
 689                 status = acpi_ut_execute_HID(node, &hid);
 690                 if (status == AE_NOT_FOUND) {
 691                         return (AE_OK);
 692                 } else if (ACPI_FAILURE(status)) {
 693                         return (AE_CTRL_DEPTH);
 694                 }
 695
 696                 no_match = ACPI_STRCMP(hid->string, info->hid);
 697                 ACPI_FREE(hid);
 698
 699                 if (no_match) {
 700                         /*
 701                          * HID does not match, attempt match within the
 702                          * list of Compatible IDs (CIDs)
 703                          */
 704                         status = acpi_ut_execute_CID(node, &cid);
 705                         if (status == AE_NOT_FOUND) {
 706                                 return (AE_OK);
 707                         } else if (ACPI_FAILURE(status)) {
 708                                 return (AE_CTRL_DEPTH);
 709                         }
 710
 711                         /* Walk the CID list */
 712
 713                         found = FALSE;
 714                         for (i = 0; i < cid->count; i++) {
 715                                 if (ACPI_STRCMP(cid->ids[i].string, info->hid)
 716                                     == 0) {
 717
 718                                         /* Found a matching CID */
 719
 720                                         found = TRUE;
 721                                         break;
 722                                 }
 723                         }
 724
 725                         ACPI_FREE(cid);
 726                         if (!found) {
 727                                 return (AE_OK);
 728                         }
 729                 }
 730         }
 731
 732         /* Run _STA to determine if device is present */
 733
 734         status = acpi_ut_execute_STA(node, &flags);
 735         if (ACPI_FAILURE(status)) {
 736                 return (AE_CTRL_DEPTH);
 737         }
 738
 739         if (!(flags & ACPI_STA_DEVICE_PRESENT) &&
 740             !(flags & ACPI_STA_DEVICE_FUNCTIONING)) {
 741                 /*
 742                  * Don't examine the children of the device only when the
 743                  * device is neither present nor functional. See ACPI spec,
 744                  * description of _STA for more information.
 745                  */
 746                 return (AE_CTRL_DEPTH);
 747         }
 748
 749         /* We have a valid device, invoke the user function */
 750
 751         status = info->user_function(obj_handle, nesting_level, info->context,
 752                                      return_value);
 753         return (status);
 754 }
 755
 756 /*******************************************************************************
 757  *
 758  * FUNCTION:    acpi_get_devices
 759  *
 760  * PARAMETERS:  HID                 - HID to search for. Can be NULL.
 761  *              user_function       - Called when a matching object is found
 762  *              context             - Passed to user function
 763  *              return_value        - Location where return value of
 764  *                                    user_function is put if terminated early
 765  *
 766  * RETURNS      Return value from the user_function if terminated early.
 767  *              Otherwise, returns NULL.
 768  *
 769  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 770  *              starting (and ending) at the object specified by start_handle.
 771  *              The user_function is called whenever an object of type
 772  *              Device is found. If the user function returns
 773  *              a non-zero value, the search is terminated immediately and this
 774  *              value is returned to the caller.
 775  *
 776  *              This is a wrapper for walk_namespace, but the callback performs
 777  *              additional filtering. Please see acpi_ns_get_device_callback.
 778  *
 779  ******************************************************************************/
 780
 781 acpi_status
 782 acpi_get_devices(const char *HID,
 783                  acpi_walk_callback user_function,
 784                  void *context, void **return_value)
 785 {
 786         acpi_status status;
 787         struct acpi_get_devices_info info;
 788
 789         ACPI_FUNCTION_TRACE(acpi_get_devices);
 790
 791         /* Parameter validation */
 792
 793         if (!user_function) {
 794                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 795         }
 796
 797         /*
 798          * We're going to call their callback from OUR callback, so we need
 799          * to know what it is, and their context parameter.
 800          */
 801         info.hid = HID;
 802         info.context = context;
 803         info.user_function = user_function;
 804
 805         /*
 806          * Lock the namespace around the walk.
 807          * The namespace will be unlocked/locked around each call
 808          * to the user function - since this function
 809          * must be allowed to make Acpi calls itself.
 810          */
 811         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 812         if (ACPI_FAILURE(status)) {
 813                 return_ACPI_STATUS(status);
 814         }
 815
 816         status = acpi_ns_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 817                                         ACPI_UINT32_MAX, ACPI_NS_WALK_UNLOCK,
 818                                         acpi_ns_get_device_callback, NULL,
 819                                         &info, return_value);
 820
 821         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 822         return_ACPI_STATUS(status);
 823 }
 824
 825 ACPI_EXPORT_SYMBOL(acpi_get_devices)
 826
 827 /*******************************************************************************
 828  *
 829  * FUNCTION:    acpi_attach_data
 830  *
 831  * PARAMETERS:  obj_handle          - Namespace node
 832  *              handler             - Handler for this attachment
 833  *              data                - Pointer to data to be attached
 834  *
 835  * RETURN:      Status
 836  *
 837  * DESCRIPTION: Attach arbitrary data and handler to a namespace node.
 838  *
 839  ******************************************************************************/
 840 acpi_status
 841 acpi_attach_data(acpi_handle obj_handle,
 842                  acpi_object_handler handler, void *data)
 843 {
 844         struct acpi_namespace_node *node;
 845         acpi_status status;
 846
 847         /* Parameter validation */
 848
 849         if (!obj_handle || !handler || !data) {
 850                 return (AE_BAD_PARAMETER);
 851         }
 852
 853         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 854         if (ACPI_FAILURE(status)) {
 855                 return (status);
 856         }
 857
 858         /* Convert and validate the handle */
 859
 860         node = acpi_ns_validate_handle(obj_handle);
 861         if (!node) {
 862                 status = AE_BAD_PARAMETER;
 863                 goto unlock_and_exit;
 864         }
 865
 866         status = acpi_ns_attach_data(node, handler, data);
 867
 868 unlock_and_exit:
 869         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 870         return (status);
 871 }
 872
 873 ACPI_EXPORT_SYMBOL(acpi_attach_data)
 874
 875 /*******************************************************************************
 876  *
 877  * FUNCTION:    acpi_detach_data
 878  *
 879  * PARAMETERS:  obj_handle          - Namespace node handle
 880  *              handler             - Handler used in call to acpi_attach_data
 881  *
 882  * RETURN:      Status
 883  *
 884  * DESCRIPTION: Remove data that was previously attached to a node.
 885  *
 886  ******************************************************************************/
 887 acpi_status
 888 acpi_detach_data(acpi_handle obj_handle, acpi_object_handler handler)
 889 {
 890         struct acpi_namespace_node *node;
 891         acpi_status status;
 892
 893         /* Parameter validation */
 894
 895         if (!obj_handle || !handler) {
 896                 return (AE_BAD_PARAMETER);
 897         }
 898
 899         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 900         if (ACPI_FAILURE(status)) {
 901                 return (status);
 902         }
 903
 904         /* Convert and validate the handle */
 905
 906         node = acpi_ns_validate_handle(obj_handle);
 907         if (!node) {
 908                 status = AE_BAD_PARAMETER;
 909                 goto unlock_and_exit;
 910         }
 911
 912         status = acpi_ns_detach_data(node, handler);
 913
 914 unlock_and_exit:
 915         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 916         return (status);
 917 }
 918
 919 ACPI_EXPORT_SYMBOL(acpi_detach_data)
 920
 921 /*******************************************************************************
 922  *
 923  * FUNCTION:    acpi_get_data
 924  *
 925  * PARAMETERS:  obj_handle          - Namespace node
 926  *              handler             - Handler used in call to attach_data
 927  *              data                - Where the data is returned
 928  *
 929  * RETURN:      Status
 930  *
 931  * DESCRIPTION: Retrieve data that was previously attached to a namespace node.
 932  *
 933  ******************************************************************************/
 934 acpi_status
 935 acpi_get_data(acpi_handle obj_handle, acpi_object_handler handler, void **data)
 936 {
 937         struct acpi_namespace_node *node;
 938         acpi_status status;
 939
 940         /* Parameter validation */
 941
 942         if (!obj_handle || !handler || !data) {
 943                 return (AE_BAD_PARAMETER);
 944         }
 945
 946         status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 947         if (ACPI_FAILURE(status)) {
 948                 return (status);
 949         }
 950
 951         /* Convert and validate the handle */
 952
 953         node = acpi_ns_validate_handle(obj_handle);
 954         if (!node) {
 955                 status = AE_BAD_PARAMETER;
 956                 goto unlock_and_exit;
 957         }
 958
 959         status = acpi_ns_get_attached_data(node, handler, data);
 960
 961 unlock_and_exit:
 962         (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 963         return (status);
 964 }
 965
 966 ACPI_EXPORT_SYMBOL(acpi_get_data)