drivers/acpi/namespace/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 <acpi/acnamesp.h>
  46
  47 #define _COMPONENT          ACPI_NAMESPACE
  48 ACPI_MODULE_NAME("nswalk")
  49
  50 /*******************************************************************************
  51  *
  52  * FUNCTION:    acpi_ns_get_next_node
  53  *
  54  * PARAMETERS:  Type                - Type of node to be searched for
  55  *              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(acpi_object_type type, struct acpi_namespace_node
  69                                                   *parent_node, struct acpi_namespace_node
  70                                                   *child_node)
  71 {
  72         struct acpi_namespace_node *next_node = NULL;
  73
  74         ACPI_FUNCTION_ENTRY();
  75
  76         if (!child_node) {
  77
  78                 /* It's really the parent's _scope_ that we want */
  79
  80                 next_node = parent_node->child;
  81         }
  82
  83         else {
  84                 /* Start search at the NEXT node */
  85
  86                 next_node = acpi_ns_get_next_valid_node(child_node);
  87         }
  88
  89         /* If any type is OK, we are done */
  90
  91         if (type == ACPI_TYPE_ANY) {
  92
  93                 /* next_node is NULL if we are at the end-of-list */
  94
  95                 return (next_node);
  96         }
  97
  98         /* Must search for the node -- but within this scope only */
  99
 100         while (next_node) {
 101
 102                 /* If type matches, we are done */
 103
 104                 if (next_node->type == type) {
 105                         return (next_node);
 106                 }
 107
 108                 /* Otherwise, move on to the next node */
 109
 110                 next_node = acpi_ns_get_next_valid_node(next_node);
 111         }
 112
 113         /* Not found */
 114
 115         return (NULL);
 116 }
 117
 118 /*******************************************************************************
 119  *
 120  * FUNCTION:    acpi_ns_walk_namespace
 121  *
 122  * PARAMETERS:  Type                - acpi_object_type to search for
 123  *              start_node          - Handle in namespace where search begins
 124  *              max_depth           - Depth to which search is to reach
 125  *              Flags               - Whether to unlock the NS before invoking
 126  *                                    the callback routine
 127  *              user_function       - Called when an object of "Type" is found
 128  *              Context             - Passed to user function
 129  *              return_value        - from the user_function if terminated early.
 130  *                                    Otherwise, returns NULL.
 131  * RETURNS:     Status
 132  *
 133  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 134  *              starting (and ending) at the node specified by start_handle.
 135  *              The user_function is called whenever a node that matches
 136  *              the type parameter is found.  If the user function returns
 137  *              a non-zero value, the search is terminated immediately and this
 138  *              value is returned to the caller.
 139  *
 140  *              The point of this procedure is to provide a generic namespace
 141  *              walk routine that can be called from multiple places to
 142  *              provide multiple services;  the User Function can be tailored
 143  *              to each task, whether it is a print function, a compare
 144  *              function, etc.
 145  *
 146  ******************************************************************************/
 147
 148 acpi_status
 149 acpi_ns_walk_namespace(acpi_object_type type,
 150                        acpi_handle start_node,
 151                        u32 max_depth,
 152                        u32 flags,
 153                        acpi_walk_callback user_function,
 154                        void *context, void **return_value)
 155 {
 156         acpi_status status;
 157         acpi_status mutex_status;
 158         struct acpi_namespace_node *child_node;
 159         struct acpi_namespace_node *parent_node;
 160         acpi_object_type child_type;
 161         u32 level;
 162
 163         ACPI_FUNCTION_TRACE(ns_walk_namespace);
 164
 165         /* Special case for the namespace Root Node */
 166
 167         if (start_node == ACPI_ROOT_OBJECT) {
 168                 start_node = acpi_gbl_root_node;
 169         }
 170
 171         /* Null child means "get first node" */
 172
 173         parent_node = start_node;
 174         child_node = NULL;
 175         child_type = ACPI_TYPE_ANY;
 176         level = 1;
 177
 178         /*
 179          * Traverse the tree of nodes until we bubble back up to where we
 180          * started. When Level is zero, the loop is done because we have
 181          * bubbled up to (and passed) the original parent handle (start_entry)
 182          */
 183         while (level > 0) {
 184
 185                 /* Get the next node in this scope.  Null if not found */
 186
 187                 status = AE_OK;
 188                 child_node =
 189                     acpi_ns_get_next_node(ACPI_TYPE_ANY, parent_node,
 190                                           child_node);
 191                 if (child_node) {
 192
 193                         /* Found next child, get the type if we are not searching for ANY */
 194
 195                         if (type != ACPI_TYPE_ANY) {
 196                                 child_type = child_node->type;
 197                         }
 198
 199                         /*
 200                          * Ignore all temporary namespace nodes (created during control
 201                          * method execution) unless told otherwise. These temporary nodes
 202                          * can cause a race condition because they can be deleted during the
 203                          * execution of the user function (if the namespace is unlocked before
 204                          * invocation of the user function.) Only the debugger namespace dump
 205                          * will examine the temporary nodes.
 206                          */
 207                         if ((child_node->flags & ANOBJ_TEMPORARY) &&
 208                             !(flags & ACPI_NS_WALK_TEMP_NODES)) {
 209                                 status = AE_CTRL_DEPTH;
 210                         }
 211
 212                         /* Type must match requested type */
 213
 214                         else if (child_type == type) {
 215                                 /*
 216                                  * Found a matching node, invoke the user callback function.
 217                                  * Unlock the namespace if flag is set.
 218                                  */
 219                                 if (flags & ACPI_NS_WALK_UNLOCK) {
 220                                         mutex_status =
 221                                             acpi_ut_release_mutex
 222                                             (ACPI_MTX_NAMESPACE);
 223                                         if (ACPI_FAILURE(mutex_status)) {
 224                                                 return_ACPI_STATUS
 225                                                     (mutex_status);
 226                                         }
 227                                 }
 228
 229                                 status =
 230                                     user_function(child_node, level, context,
 231                                                   return_value);
 232
 233                                 if (flags & ACPI_NS_WALK_UNLOCK) {
 234                                         mutex_status =
 235                                             acpi_ut_acquire_mutex
 236                                             (ACPI_MTX_NAMESPACE);
 237                                         if (ACPI_FAILURE(mutex_status)) {
 238                                                 return_ACPI_STATUS
 239                                                     (mutex_status);
 240                                         }
 241                                 }
 242
 243                                 switch (status) {
 244                                 case AE_OK:
 245                                 case AE_CTRL_DEPTH:
 246
 247                                         /* Just keep going */
 248                                         break;
 249
 250                                 case AE_CTRL_TERMINATE:
 251
 252                                         /* Exit now, with OK status */
 253
 254                                         return_ACPI_STATUS(AE_OK);
 255
 256                                 default:
 257
 258                                         /* All others are valid exceptions */
 259
 260                                         return_ACPI_STATUS(status);
 261                                 }
 262                         }
 263
 264                         /*
 265                          * Depth first search: Attempt to go down another level in the
 266                          * namespace if we are allowed to.  Don't go any further if we have
 267                          * reached the caller specified maximum depth or if the user
 268                          * function has specified that the maximum depth has been reached.
 269                          */
 270                         if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
 271                                 if (acpi_ns_get_next_node
 272                                     (ACPI_TYPE_ANY, child_node, NULL)) {
 273
 274                                         /* There is at least one child of this node, visit it */
 275
 276                                         level++;
 277                                         parent_node = child_node;
 278                                         child_node = NULL;
 279                                 }
 280                         }
 281                 } else {
 282                         /*
 283                          * No more children of this node (acpi_ns_get_next_node failed), go
 284                          * back upwards in the namespace tree to the node's parent.
 285                          */
 286                         level--;
 287                         child_node = parent_node;
 288                         parent_node = acpi_ns_get_parent_node(parent_node);
 289                 }
 290         }
 291
 292         /* Complete walk, not terminated by user function */
 293
 294         return_ACPI_STATUS(AE_OK);
 295 }