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 - 2006, 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 #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,
  69                                                   struct acpi_namespace_node
  70                                                   *parent_node,
  71                                                   struct acpi_namespace_node
  72                                                   *child_node)
  73 {
  74         struct acpi_namespace_node *next_node = NULL;
  75
  76         ACPI_FUNCTION_ENTRY();
  77
  78         if (!child_node) {
  79                 /* It's really the parent's _scope_ that we want */
  80
  81                 if (parent_node->child) {
  82                         next_node = parent_node->child;
  83                 }
  84         }
  85
  86         else {
  87                 /* Start search at the NEXT node */
  88
  89                 next_node = acpi_ns_get_next_valid_node(child_node);
  90         }
  91
  92         /* If any type is OK, we are done */
  93
  94         if (type == ACPI_TYPE_ANY) {
  95                 /* next_node is NULL if we are at the end-of-list */
  96
  97                 return (next_node);
  98         }
  99
 100         /* Must search for the node -- but within this scope only */
 101
 102         while (next_node) {
 103                 /* If type matches, we are done */
 104
 105                 if (next_node->type == type) {
 106                         return (next_node);
 107                 }
 108
 109                 /* Otherwise, move on to the next node */
 110
 111                 next_node = acpi_ns_get_next_valid_node(next_node);
 112         }
 113
 114         /* Not found */
 115
 116         return (NULL);
 117 }
 118
 119 /*******************************************************************************
 120  *
 121  * FUNCTION:    acpi_ns_walk_namespace
 122  *
 123  * PARAMETERS:  Type                - acpi_object_type to search for
 124  *              start_node          - Handle in namespace where search begins
 125  *              max_depth           - Depth to which search is to reach
 126  *              unlock_before_callback- Whether to unlock the NS before invoking
 127  *                                    the callback routine
 128  *              user_function       - Called when an object of "Type" is found
 129  *              Context             - Passed to user function
 130  *              return_value        - from the user_function if terminated early.
 131  *                                    Otherwise, returns NULL.
 132  * RETURNS:     Status
 133  *
 134  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 135  *              starting (and ending) at the node specified by start_handle.
 136  *              The user_function is called whenever a node that matches
 137  *              the type parameter is found.  If the user function returns
 138  *              a non-zero value, the search is terminated immediately and this
 139  *              value is returned to the caller.
 140  *
 141  *              The point of this procedure is to provide a generic namespace
 142  *              walk routine that can be called from multiple places to
 143  *              provide multiple services;  the User Function can be tailored
 144  *              to each task, whether it is a print function, a compare
 145  *              function, etc.
 146  *
 147  ******************************************************************************/
 148
 149 acpi_status
 150 acpi_ns_walk_namespace(acpi_object_type type,
 151                        acpi_handle start_node,
 152                        u32 max_depth,
 153                        u8 unlock_before_callback,
 154                        acpi_walk_callback user_function,
 155                        void *context, void **return_value)
 156 {
 157         acpi_status status;
 158         acpi_status mutex_status;
 159         struct acpi_namespace_node *child_node;
 160         struct acpi_namespace_node *parent_node;
 161         acpi_object_type child_type;
 162         u32 level;
 163
 164         ACPI_FUNCTION_TRACE("ns_walk_namespace");
 165
 166         /* Special case for the namespace Root Node */
 167
 168         if (start_node == ACPI_ROOT_OBJECT) {
 169                 start_node = acpi_gbl_root_node;
 170         }
 171
 172         /* Null child means "get first node" */
 173
 174         parent_node = start_node;
 175         child_node = NULL;
 176         child_type = ACPI_TYPE_ANY;
 177         level = 1;
 178
 179         /*
 180          * Traverse the tree of nodes until we bubble back up to where we
 181          * started. When Level is zero, the loop is done because we have
 182          * bubbled up to (and passed) the original parent handle (start_entry)
 183          */
 184         while (level > 0) {
 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 node, Get the type if we are not
 194                          * searching for ANY
 195                          */
 196                         if (type != ACPI_TYPE_ANY) {
 197                                 child_type = child_node->type;
 198                         }
 199
 200                         if (child_type == type) {
 201                                 /*
 202                                  * Found a matching node, invoke the user
 203                                  * callback function
 204                                  */
 205                                 if (unlock_before_callback) {
 206                                         mutex_status =
 207                                             acpi_ut_release_mutex
 208                                             (ACPI_MTX_NAMESPACE);
 209                                         if (ACPI_FAILURE(mutex_status)) {
 210                                                 return_ACPI_STATUS
 211                                                     (mutex_status);
 212                                         }
 213                                 }
 214
 215                                 status = user_function(child_node, level,
 216                                                        context, return_value);
 217
 218                                 if (unlock_before_callback) {
 219                                         mutex_status =
 220                                             acpi_ut_acquire_mutex
 221                                             (ACPI_MTX_NAMESPACE);
 222                                         if (ACPI_FAILURE(mutex_status)) {
 223                                                 return_ACPI_STATUS
 224                                                     (mutex_status);
 225                                         }
 226                                 }
 227
 228                                 switch (status) {
 229                                 case AE_OK:
 230                                 case AE_CTRL_DEPTH:
 231
 232                                         /* Just keep going */
 233                                         break;
 234
 235                                 case AE_CTRL_TERMINATE:
 236
 237                                         /* Exit now, with OK status */
 238
 239                                         return_ACPI_STATUS(AE_OK);
 240
 241                                 default:
 242
 243                                         /* All others are valid exceptions */
 244
 245                                         return_ACPI_STATUS(status);
 246                                 }
 247                         }
 248
 249                         /*
 250                          * Depth first search:
 251                          * Attempt to go down another level in the namespace
 252                          * if we are allowed to.  Don't go any further if we
 253                          * have reached the caller specified maximum depth
 254                          * or if the user function has specified that the
 255                          * maximum depth has been reached.
 256                          */
 257                         if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
 258                                 if (acpi_ns_get_next_node
 259                                     (ACPI_TYPE_ANY, child_node, NULL)) {
 260                                         /*
 261                                          * There is at least one child of this
 262                                          * node, visit the onde
 263                                          */
 264                                         level++;
 265                                         parent_node = child_node;
 266                                         child_node = NULL;
 267                                 }
 268                         }
 269                 } else {
 270                         /*
 271                          * No more children of this node (acpi_ns_get_next_node
 272                          * failed), go back upwards in the namespace tree to
 273                          * the node's parent.
 274                          */
 275                         level--;
 276                         child_node = parent_node;
 277                         parent_node = acpi_ns_get_parent_node(parent_node);
 278                 }
 279         }
 280
 281         /* Complete walk, not terminated by user function */
 282
 283         return_ACPI_STATUS(AE_OK);
 284 }