drivers/acpi/acpica/nswalk.c

   1 /******************************************************************************
   2  *
   3  * Module Name: nswalk - Functions for walking the ACPI namespace
   4  *
   5  *****************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, 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 "acnamesp.h"
  47
  48 #define _COMPONENT          ACPI_NAMESPACE
  49 ACPI_MODULE_NAME("nswalk")
  50
  51 /*******************************************************************************
  52  *
  53  * FUNCTION:    acpi_ns_get_next_node
  54  *
  55  * PARAMETERS:  parent_node         - Parent node whose children we are
  56  *                                    getting
  57  *              child_node          - Previous child that was found.
  58  *                                    The NEXT child will be returned
  59  *
  60  * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
  61  *                                    none is found.
  62  *
  63  * DESCRIPTION: Return the next peer node within the namespace.  If Handle
  64  *              is valid, Scope is ignored.  Otherwise, the first node
  65  *              within Scope is returned.
  66  *
  67  ******************************************************************************/
  68 struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node
  69                                                   *parent_node,
  70                                                   struct acpi_namespace_node
  71                                                   *child_node)
  72 {
  73         ACPI_FUNCTION_ENTRY();
  74
  75         if (!child_node) {
  76
  77                 /* It's really the parent's _scope_ that we want */
  78
  79                 return parent_node->child;
  80         }
  81
  82         /*
  83          * Get the next node.
  84          *
  85          * If we are at the end of this peer list, return NULL
  86          */
  87         if (child_node->flags & ANOBJ_END_OF_PEER_LIST) {
  88                 return NULL;
  89         }
  90
  91         /* Otherwise just return the next peer */
  92
  93         return child_node->peer;
  94 }
  95
  96 /*******************************************************************************
  97  *
  98  * FUNCTION:    acpi_ns_get_next_node_typed
  99  *
 100  * PARAMETERS:  Type                - Type of node to be searched for
 101  *              parent_node         - Parent node whose children we are
 102  *                                    getting
 103  *              child_node          - Previous child that was found.
 104  *                                    The NEXT child will be returned
 105  *
 106  * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
 107  *                                    none is found.
 108  *
 109  * DESCRIPTION: Return the next peer node within the namespace.  If Handle
 110  *              is valid, Scope is ignored.  Otherwise, the first node
 111  *              within Scope is returned.
 112  *
 113  ******************************************************************************/
 114
 115 struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
 116                                                         struct
 117                                                         acpi_namespace_node
 118                                                         *parent_node,
 119                                                         struct
 120                                                         acpi_namespace_node
 121                                                         *child_node)
 122 {
 123         struct acpi_namespace_node *next_node = NULL;
 124
 125         ACPI_FUNCTION_ENTRY();
 126
 127         next_node = acpi_ns_get_next_node(parent_node, child_node);
 128
 129
 130         /* If any type is OK, we are done */
 131
 132         if (type == ACPI_TYPE_ANY) {
 133
 134                 /* next_node is NULL if we are at the end-of-list */
 135
 136                 return (next_node);
 137         }
 138
 139         /* Must search for the node -- but within this scope only */
 140
 141         while (next_node) {
 142
 143                 /* If type matches, we are done */
 144
 145                 if (next_node->type == type) {
 146                         return (next_node);
 147                 }
 148
 149                 /* Otherwise, move on to the next node */
 150
 151                 next_node = acpi_ns_get_next_valid_node(next_node);
 152         }
 153
 154         /* Not found */
 155
 156         return (NULL);
 157 }
 158
 159 /*******************************************************************************
 160  *
 161  * FUNCTION:    acpi_ns_walk_namespace
 162  *
 163  * PARAMETERS:  Type                - acpi_object_type to search for
 164  *              start_node          - Handle in namespace where search begins
 165  *              max_depth           - Depth to which search is to reach
 166  *              Flags               - Whether to unlock the NS before invoking
 167  *                                    the callback routine
 168  *              pre_order_visit     - Called during tree pre-order visit
 169  *                                    when an object of "Type" is found
 170  *              post_order_visit    - Called during tree post-order visit
 171  *                                    when an object of "Type" is found
 172  *              Context             - Passed to user function(s) above
 173  *              return_value        - from the user_function if terminated
 174  *                                    early. Otherwise, returns NULL.
 175  * RETURNS:     Status
 176  *
 177  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 178  *              starting (and ending) at the node specified by start_handle.
 179  *              The callback function is called whenever a node that matches
 180  *              the type parameter is found. If the callback function returns
 181  *              a non-zero value, the search is terminated immediately and
 182  *              this value is returned to the caller.
 183  *
 184  *              The point of this procedure is to provide a generic namespace
 185  *              walk routine that can be called from multiple places to
 186  *              provide multiple services; the callback function(s) can be
 187  *              tailored to each task, whether it is a print function,
 188  *              a compare function, etc.
 189  *
 190  ******************************************************************************/
 191
 192 acpi_status
 193 acpi_ns_walk_namespace(acpi_object_type type,
 194                        acpi_handle start_node,
 195                        u32 max_depth,
 196                        u32 flags,
 197                        acpi_walk_callback pre_order_visit,
 198                        acpi_walk_callback post_order_visit,
 199                        void *context, void **return_value)
 200 {
 201         acpi_status status;
 202         acpi_status mutex_status;
 203         struct acpi_namespace_node *child_node;
 204         struct acpi_namespace_node *parent_node;
 205         acpi_object_type child_type;
 206         u32 level;
 207         u8 node_previously_visited = FALSE;
 208
 209         ACPI_FUNCTION_TRACE(ns_walk_namespace);
 210
 211         /* Special case for the namespace Root Node */
 212
 213         if (start_node == ACPI_ROOT_OBJECT) {
 214                 start_node = acpi_gbl_root_node;
 215         }
 216
 217         /* Null child means "get first node" */
 218
 219         parent_node = start_node;
 220         child_node = acpi_ns_get_next_node(parent_node, NULL);
 221         child_type = ACPI_TYPE_ANY;
 222         level = 1;
 223
 224         /*
 225          * Traverse the tree of nodes until we bubble back up to where we
 226          * started. When Level is zero, the loop is done because we have
 227          * bubbled up to (and passed) the original parent handle (start_entry)
 228          */
 229         while (level > 0 && child_node) {
 230                 status = AE_OK;
 231
 232                 /* Found next child, get the type if we are not searching for ANY */
 233
 234                 if (type != ACPI_TYPE_ANY) {
 235                         child_type = child_node->type;
 236                 }
 237
 238                 /*
 239                  * Ignore all temporary namespace nodes (created during control
 240                  * method execution) unless told otherwise. These temporary nodes
 241                  * can cause a race condition because they can be deleted during
 242                  * the execution of the user function (if the namespace is
 243                  * unlocked before invocation of the user function.) Only the
 244                  * debugger namespace dump will examine the temporary nodes.
 245                  */
 246                 if ((child_node->flags & ANOBJ_TEMPORARY) &&
 247                     !(flags & ACPI_NS_WALK_TEMP_NODES)) {
 248                         status = AE_CTRL_DEPTH;
 249                 }
 250
 251                 /* Type must match requested type */
 252
 253                 else if (child_type == type) {
 254                         /*
 255                          * Found a matching node, invoke the user callback function.
 256                          * Unlock the namespace if flag is set.
 257                          */
 258                         if (flags & ACPI_NS_WALK_UNLOCK) {
 259                                 mutex_status =
 260                                     acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 261                                 if (ACPI_FAILURE(mutex_status)) {
 262                                         return_ACPI_STATUS(mutex_status);
 263                                 }
 264                         }
 265
 266                         /*
 267                          * Invoke the user function, either pre-order or post-order
 268                          * or both.
 269                          */
 270                         if (!node_previously_visited) {
 271                                 if (pre_order_visit) {
 272                                         status =
 273                                             pre_order_visit(child_node, level,
 274                                                             context,
 275                                                             return_value);
 276                                 }
 277                         } else {
 278                                 if (post_order_visit) {
 279                                         status =
 280                                             post_order_visit(child_node, level,
 281                                                              context,
 282                                                              return_value);
 283                                 }
 284                         }
 285
 286                         if (flags & ACPI_NS_WALK_UNLOCK) {
 287                                 mutex_status =
 288                                     acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 289                                 if (ACPI_FAILURE(mutex_status)) {
 290                                         return_ACPI_STATUS(mutex_status);
 291                                 }
 292                         }
 293
 294                         switch (status) {
 295                         case AE_OK:
 296                         case AE_CTRL_DEPTH:
 297
 298                                 /* Just keep going */
 299                                 break;
 300
 301                         case AE_CTRL_TERMINATE:
 302
 303                                 /* Exit now, with OK status */
 304
 305                                 return_ACPI_STATUS(AE_OK);
 306
 307                         default:
 308
 309                                 /* All others are valid exceptions */
 310
 311                                 return_ACPI_STATUS(status);
 312                         }
 313                 }
 314
 315                 /*
 316                  * Depth first search: Attempt to go down another level in the
 317                  * namespace if we are allowed to.  Don't go any further if we have
 318                  * reached the caller specified maximum depth or if the user
 319                  * function has specified that the maximum depth has been reached.
 320                  */
 321                 if (!node_previously_visited &&
 322                     (level < max_depth) && (status != AE_CTRL_DEPTH)) {
 323                         if (child_node->child) {
 324
 325                                 /* There is at least one child of this node, visit it */
 326
 327                                 level++;
 328                                 parent_node = child_node;
 329                                 child_node =
 330                                     acpi_ns_get_next_node(parent_node, NULL);
 331                                 continue;
 332                         }
 333                 }
 334
 335                 /* No more children, re-visit this node */
 336
 337                 if (!node_previously_visited) {
 338                         node_previously_visited = TRUE;
 339                         continue;
 340                 }
 341
 342                 /* No more children, visit peers */
 343
 344                 child_node = acpi_ns_get_next_node(parent_node, child_node);
 345                 if (child_node) {
 346                         node_previously_visited = FALSE;
 347                 }
 348
 349                 /* No peers, re-visit parent */
 350
 351                 else {
 352                         /*
 353                          * No more children of this node (acpi_ns_get_next_node failed), go
 354                          * back upwards in the namespace tree to the node's parent.
 355                          */
 356                         level--;
 357                         child_node = parent_node;
 358                         parent_node = acpi_ns_get_parent_node(parent_node);
 359
 360                         node_previously_visited = TRUE;
 361                 }
 362         }
 363
 364         /* Complete walk, not terminated by user function */
 365
 366         return_ACPI_STATUS(AE_OK);
 367 }