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