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 - 2005, R. Byron Moore
   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
  45 #include <acpi/acpi.h>
  46 #include <acpi/acnamesp.h>
  47
  48
  49 #define _COMPONENT          ACPI_NAMESPACE
  50          ACPI_MODULE_NAME    ("nswalk")
  51
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    acpi_ns_get_next_node
  56  *
  57  * PARAMETERS:  Type                - Type of node to be searched for
  58  *              parent_node         - Parent node whose children we are
  59  *                                     getting
  60  *              child_node          - Previous child that was found.
  61  *                                    The NEXT child will be returned
  62  *
  63  * RETURN:      struct acpi_namespace_node - Pointer to the NEXT child or NULL if
  64  *                                    none is found.
  65  *
  66  * DESCRIPTION: Return the next peer node within the namespace.  If Handle
  67  *              is valid, Scope is ignored.  Otherwise, the first node
  68  *              within Scope is returned.
  69  *
  70  ******************************************************************************/
  71
  72 struct acpi_namespace_node *
  73 acpi_ns_get_next_node (
  74         acpi_object_type                type,
  75         struct acpi_namespace_node      *parent_node,
  76         struct acpi_namespace_node      *child_node)
  77 {
  78         struct acpi_namespace_node      *next_node = NULL;
  79
  80
  81         ACPI_FUNCTION_ENTRY ();
  82
  83
  84         if (!child_node) {
  85                 /* It's really the parent's _scope_ that we want */
  86
  87                 if (parent_node->child) {
  88                         next_node = parent_node->child;
  89                 }
  90         }
  91
  92         else {
  93                 /* Start search at the NEXT node */
  94
  95                 next_node = acpi_ns_get_next_valid_node (child_node);
  96         }
  97
  98         /* If any type is OK, we are done */
  99
 100         if (type == ACPI_TYPE_ANY) {
 101                 /* next_node is NULL if we are at the end-of-list */
 102
 103                 return (next_node);
 104         }
 105
 106         /* Must search for the node -- but within this scope only */
 107
 108         while (next_node) {
 109                 /* If type matches, we are done */
 110
 111                 if (next_node->type == type) {
 112                         return (next_node);
 113                 }
 114
 115                 /* Otherwise, move on to the next node */
 116
 117                 next_node = acpi_ns_get_next_valid_node (next_node);
 118         }
 119
 120         /* Not found */
 121
 122         return (NULL);
 123 }
 124
 125
 126 /*******************************************************************************
 127  *
 128  * FUNCTION:    acpi_ns_walk_namespace
 129  *
 130  * PARAMETERS:  Type                - acpi_object_type to search for
 131  *              start_node          - Handle in namespace where search begins
 132  *              max_depth           - Depth to which search is to reach
 133  *              unlock_before_callback- Whether to unlock the NS before invoking
 134  *                                    the callback routine
 135  *              user_function       - Called when an object of "Type" is found
 136  *              Context             - Passed to user function
 137  *              return_value        - from the user_function if terminated early.
 138  *                                    Otherwise, returns NULL.
 139  * RETURNS:     Status
 140  *
 141  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 142  *              starting (and ending) at the node specified by start_handle.
 143  *              The user_function is called whenever a node that matches
 144  *              the type parameter is found.  If the user function returns
 145  *              a non-zero value, the search is terminated immediately and this
 146  *              value is returned to the caller.
 147  *
 148  *              The point of this procedure is to provide a generic namespace
 149  *              walk routine that can be called from multiple places to
 150  *              provide multiple services;  the User Function can be tailored
 151  *              to each task, whether it is a print function, a compare
 152  *              function, etc.
 153  *
 154  ******************************************************************************/
 155
 156 acpi_status
 157 acpi_ns_walk_namespace (
 158         acpi_object_type                type,
 159         acpi_handle                     start_node,
 160         u32                             max_depth,
 161         u8                              unlock_before_callback,
 162         acpi_walk_callback              user_function,
 163         void                            *context,
 164         void                            **return_value)
 165 {
 166         acpi_status                     status;
 167         acpi_status                     mutex_status;
 168         struct acpi_namespace_node      *child_node;
 169         struct acpi_namespace_node      *parent_node;
 170         acpi_object_type                child_type;
 171         u32                             level;
 172
 173
 174         ACPI_FUNCTION_TRACE ("ns_walk_namespace");
 175
 176
 177         /* Special case for the namespace Root Node */
 178
 179         if (start_node == ACPI_ROOT_OBJECT) {
 180                 start_node = acpi_gbl_root_node;
 181         }
 182
 183         /* Null child means "get first node" */
 184
 185         parent_node = start_node;
 186         child_node  = NULL;
 187         child_type  = ACPI_TYPE_ANY;
 188         level       = 1;
 189
 190         /*
 191          * Traverse the tree of nodes until we bubble back up to where we
 192          * started. When Level is zero, the loop is done because we have
 193          * bubbled up to (and passed) the original parent handle (start_entry)
 194          */
 195         while (level > 0) {
 196                 /* Get the next node in this scope.  Null if not found */
 197
 198                 status = AE_OK;
 199                 child_node = acpi_ns_get_next_node (ACPI_TYPE_ANY, parent_node, child_node);
 200                 if (child_node) {
 201                         /*
 202                          * Found node, Get the type if we are not
 203                          * searching for ANY
 204                          */
 205                         if (type != ACPI_TYPE_ANY) {
 206                                 child_type = child_node->type;
 207                         }
 208
 209                         if (child_type == type) {
 210                                 /*
 211                                  * Found a matching node, invoke the user
 212                                  * callback function
 213                                  */
 214                                 if (unlock_before_callback) {
 215                                         mutex_status = acpi_ut_release_mutex (ACPI_MTX_NAMESPACE);
 216                                         if (ACPI_FAILURE (mutex_status)) {
 217                                                 return_ACPI_STATUS (mutex_status);
 218                                         }
 219                                 }
 220
 221                                 status = user_function (child_node, level,
 222                                                  context, return_value);
 223
 224                                 if (unlock_before_callback) {
 225                                         mutex_status = acpi_ut_acquire_mutex (ACPI_MTX_NAMESPACE);
 226                                         if (ACPI_FAILURE (mutex_status)) {
 227                                                 return_ACPI_STATUS (mutex_status);
 228                                         }
 229                                 }
 230
 231                                 switch (status) {
 232                                 case AE_OK:
 233                                 case AE_CTRL_DEPTH:
 234
 235                                         /* Just keep going */
 236                                         break;
 237
 238                                 case AE_CTRL_TERMINATE:
 239
 240                                         /* Exit now, with OK status */
 241
 242                                         return_ACPI_STATUS (AE_OK);
 243
 244                                 default:
 245
 246                                         /* All others are valid exceptions */
 247
 248                                         return_ACPI_STATUS (status);
 249                                 }
 250                         }
 251
 252                         /*
 253                          * Depth first search:
 254                          * Attempt to go down another level in the namespace
 255                          * if we are allowed to.  Don't go any further if we
 256                          * have reached the caller specified maximum depth
 257                          * or if the user function has specified that the
 258                          * maximum depth has been reached.
 259                          */
 260                         if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
 261                                 if (acpi_ns_get_next_node (ACPI_TYPE_ANY, child_node, NULL)) {
 262                                         /*
 263                                          * There is at least one child of this
 264                                          * node, visit the onde
 265                                          */
 266                                         level++;
 267                                         parent_node = child_node;
 268                                         child_node = NULL;
 269                                 }
 270                         }
 271                 }
 272                 else {
 273                         /*
 274                          * No more children of this node (acpi_ns_get_next_node
 275                          * failed), go back upwards in the namespace tree to
 276                          * the node's parent.
 277                          */
 278                         level--;
 279                         child_node = parent_node;
 280                         parent_node = acpi_ns_get_parent_node (parent_node);
 281                 }
 282         }
 283
 284         /* Complete walk, not terminated by user function */
 285
 286         return_ACPI_STATUS (AE_OK);
 287 }
 288
 289