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 - 2016, 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         /* Otherwise just return the next peer */
  83
  84         return (child_node->peer);
  85 }
  86
  87 /*******************************************************************************
  88  *
  89  * FUNCTION:    acpi_ns_get_next_node_typed
  90  *
  91  * PARAMETERS:  type                - Type of node to be searched for
  92  *              parent_node         - Parent node whose children we are
  93  *                                    getting
  94  *              child_node          - Previous child that was found.
  95  *                                    The NEXT child will be returned
  96  *
  97  * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
  98  *                                    none is found.
  99  *
 100  * DESCRIPTION: Return the next peer node within the namespace. If Handle
 101  *              is valid, Scope is ignored. Otherwise, the first node
 102  *              within Scope is returned.
 103  *
 104  ******************************************************************************/
 105
 106 struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,
 107                                                         struct
 108                                                         acpi_namespace_node
 109                                                         *parent_node,
 110                                                         struct
 111                                                         acpi_namespace_node
 112                                                         *child_node)
 113 {
 114         struct acpi_namespace_node *next_node = NULL;
 115
 116         ACPI_FUNCTION_ENTRY();
 117
 118         next_node = acpi_ns_get_next_node(parent_node, child_node);
 119
 120
 121         /* If any type is OK, we are done */
 122
 123         if (type == ACPI_TYPE_ANY) {
 124
 125                 /* next_node is NULL if we are at the end-of-list */
 126
 127                 return (next_node);
 128         }
 129
 130         /* Must search for the node -- but within this scope only */
 131
 132         while (next_node) {
 133
 134                 /* If type matches, we are done */
 135
 136                 if (next_node->type == type) {
 137                         return (next_node);
 138                 }
 139
 140                 /* Otherwise, move on to the next peer node */
 141
 142                 next_node = next_node->peer;
 143         }
 144
 145         /* Not found */
 146
 147         return (NULL);
 148 }
 149
 150 /*******************************************************************************
 151  *
 152  * FUNCTION:    acpi_ns_walk_namespace
 153  *
 154  * PARAMETERS:  type                - acpi_object_type to search for
 155  *              start_node          - Handle in namespace where search begins
 156  *              max_depth           - Depth to which search is to reach
 157  *              flags               - Whether to unlock the NS before invoking
 158  *                                    the callback routine
 159  *              descending_callback - Called during tree descent
 160  *                                    when an object of "Type" is found
 161  *              ascending_callback  - Called during tree ascent
 162  *                                    when an object of "Type" is found
 163  *              context             - Passed to user function(s) above
 164  *              return_value        - from the user_function if terminated
 165  *                                    early. Otherwise, returns NULL.
 166  * RETURNS:     Status
 167  *
 168  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 169  *              starting (and ending) at the node specified by start_handle.
 170  *              The callback function is called whenever a node that matches
 171  *              the type parameter is found. If the callback function returns
 172  *              a non-zero value, the search is terminated immediately and
 173  *              this value is returned to the caller.
 174  *
 175  *              The point of this procedure is to provide a generic namespace
 176  *              walk routine that can be called from multiple places to
 177  *              provide multiple services; the callback function(s) can be
 178  *              tailored to each task, whether it is a print function,
 179  *              a compare function, etc.
 180  *
 181  ******************************************************************************/
 182
 183 acpi_status
 184 acpi_ns_walk_namespace(acpi_object_type type,
 185                        acpi_handle start_node,
 186                        u32 max_depth,
 187                        u32 flags,
 188                        acpi_walk_callback descending_callback,
 189                        acpi_walk_callback ascending_callback,
 190                        void *context, void **return_value)
 191 {
 192         acpi_status status;
 193         acpi_status mutex_status;
 194         struct acpi_namespace_node *child_node;
 195         struct acpi_namespace_node *parent_node;
 196         acpi_object_type child_type;
 197         u32 level;
 198         u8 node_previously_visited = FALSE;
 199
 200         ACPI_FUNCTION_TRACE(ns_walk_namespace);
 201
 202         /* Special case for the namespace Root Node */
 203
 204         if (start_node == ACPI_ROOT_OBJECT) {
 205                 start_node = acpi_gbl_root_node;
 206         }
 207
 208         /* Null child means "get first node" */
 209
 210         parent_node = start_node;
 211         child_node = acpi_ns_get_next_node(parent_node, NULL);
 212         child_type = ACPI_TYPE_ANY;
 213         level = 1;
 214
 215         /*
 216          * Traverse the tree of nodes until we bubble back up to where we
 217          * started. When Level is zero, the loop is done because we have
 218          * bubbled up to (and passed) the original parent handle (start_entry)
 219          */
 220         while (level > 0 && child_node) {
 221                 status = AE_OK;
 222
 223                 /* Found next child, get the type if we are not searching for ANY */
 224
 225                 if (type != ACPI_TYPE_ANY) {
 226                         child_type = child_node->type;
 227                 }
 228
 229                 /*
 230                  * Ignore all temporary namespace nodes (created during control
 231                  * method execution) unless told otherwise. These temporary nodes
 232                  * can cause a race condition because they can be deleted during
 233                  * the execution of the user function (if the namespace is
 234                  * unlocked before invocation of the user function.) Only the
 235                  * debugger namespace dump will examine the temporary nodes.
 236                  */
 237                 if ((child_node->flags & ANOBJ_TEMPORARY) &&
 238                     !(flags & ACPI_NS_WALK_TEMP_NODES)) {
 239                         status = AE_CTRL_DEPTH;
 240                 }
 241
 242                 /* Type must match requested type */
 243
 244                 else if (child_type == type) {
 245                         /*
 246                          * Found a matching node, invoke the user callback function.
 247                          * Unlock the namespace if flag is set.
 248                          */
 249                         if (flags & ACPI_NS_WALK_UNLOCK) {
 250                                 mutex_status =
 251                                     acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
 252                                 if (ACPI_FAILURE(mutex_status)) {
 253                                         return_ACPI_STATUS(mutex_status);
 254                                 }
 255                         }
 256
 257                         /*
 258                          * Invoke the user function, either descending, ascending,
 259                          * or both.
 260                          */
 261                         if (!node_previously_visited) {
 262                                 if (descending_callback) {
 263                                         status =
 264                                             descending_callback(child_node,
 265                                                                 level, context,
 266                                                                 return_value);
 267                                 }
 268                         } else {
 269                                 if (ascending_callback) {
 270                                         status =
 271                                             ascending_callback(child_node,
 272                                                                level, context,
 273                                                                return_value);
 274                                 }
 275                         }
 276
 277                         if (flags & ACPI_NS_WALK_UNLOCK) {
 278                                 mutex_status =
 279                                     acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
 280                                 if (ACPI_FAILURE(mutex_status)) {
 281                                         return_ACPI_STATUS(mutex_status);
 282                                 }
 283                         }
 284
 285                         switch (status) {
 286                         case AE_OK:
 287                         case AE_CTRL_DEPTH:
 288
 289                                 /* Just keep going */
 290                                 break;
 291
 292                         case AE_CTRL_TERMINATE:
 293
 294                                 /* Exit now, with OK status */
 295
 296                                 return_ACPI_STATUS(AE_OK);
 297
 298                         default:
 299
 300                                 /* All others are valid exceptions */
 301
 302                                 return_ACPI_STATUS(status);
 303                         }
 304                 }
 305
 306                 /*
 307                  * Depth first search: Attempt to go down another level in the
 308                  * namespace if we are allowed to. Don't go any further if we have
 309                  * reached the caller specified maximum depth or if the user
 310                  * function has specified that the maximum depth has been reached.
 311                  */
 312                 if (!node_previously_visited &&
 313                     (level < max_depth) && (status != AE_CTRL_DEPTH)) {
 314                         if (child_node->child) {
 315
 316                                 /* There is at least one child of this node, visit it */
 317
 318                                 level++;
 319                                 parent_node = child_node;
 320                                 child_node =
 321                                     acpi_ns_get_next_node(parent_node, NULL);
 322                                 continue;
 323                         }
 324                 }
 325
 326                 /* No more children, re-visit this node */
 327
 328                 if (!node_previously_visited) {
 329                         node_previously_visited = TRUE;
 330                         continue;
 331                 }
 332
 333                 /* No more children, visit peers */
 334
 335                 child_node = acpi_ns_get_next_node(parent_node, child_node);
 336                 if (child_node) {
 337                         node_previously_visited = FALSE;
 338                 }
 339
 340                 /* No peers, re-visit parent */
 341
 342                 else {
 343                         /*
 344                          * No more children of this node (acpi_ns_get_next_node failed), go
 345                          * back upwards in the namespace tree to the node's parent.
 346                          */
 347                         level--;
 348                         child_node = parent_node;
 349                         parent_node = parent_node->parent;
 350
 351                         node_previously_visited = TRUE;
 352                 }
 353         }
 354
 355         /* Complete walk, not terminated by user function */
 356
 357         return_ACPI_STATUS(AE_OK);
 358 }