git.oblomov.eu Git - linux-2.6/blob - 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  *              user_function       - Called when an object of "Type" is found
 169  *              Context             - Passed to user function
 170  *              return_value        - from the user_function if terminated early.
 171  *                                    Otherwise, returns NULL.
 172  * RETURNS:     Status
 173  *
 174  * DESCRIPTION: Performs a modified depth-first walk of the namespace tree,
 175  *              starting (and ending) at the node specified by start_handle.
 176  *              The user_function is called whenever a node that matches
 177  *              the type parameter is found.  If the user function returns
 178  *              a non-zero value, the search is terminated immediately and
 179  *              this value is returned to the caller.
 180  *
 181  *              The point of this procedure is to provide a generic namespace
 182  *              walk routine that can be called from multiple places to
 183  *              provide multiple services;  the User Function can be tailored
 184  *              to each task, whether it is a print function, a compare
 185  *              function, etc.
 186  *
 187  ******************************************************************************/
 188
 189 acpi_status
 190 acpi_ns_walk_namespace(acpi_object_type type,
 191                        acpi_handle start_node,
 192                        u32 max_depth,
 193                        u32 flags,
 194                        acpi_walk_callback user_function,
 195                        void *context, void **return_value)
 196 {
 197         acpi_status status;
 198         acpi_status mutex_status;
 199         struct acpi_namespace_node *child_node;
 200         struct acpi_namespace_node *parent_node;
 201         acpi_object_type child_type;
 202         u32 level;
 203
 204         ACPI_FUNCTION_TRACE(ns_walk_namespace);
 205
 206         /* Special case for the namespace Root Node */
 207
 208         if (start_node == ACPI_ROOT_OBJECT) {
 209                 start_node = acpi_gbl_root_node;
 210         }
 211
 212         /* Null child means "get first node" */
 213
 214         parent_node = start_node;
 215         child_node = NULL;
 216         child_type = ACPI_TYPE_ANY;
 217         level = 1;
 218
 219         /*
 220          * Traverse the tree of nodes until we bubble back up to where we
 221          * started. When Level is zero, the loop is done because we have
 222          * bubbled up to (and passed) the original parent handle (start_entry)
 223          */
 224         while (level > 0) {
 225
 226                 /* Get the next node in this scope.  Null if not found */
 227
 228                 status = AE_OK;
 229                 child_node = acpi_ns_get_next_node(parent_node, child_node);
 230                 if (child_node) {
 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
 261                                             (ACPI_MTX_NAMESPACE);
 262                                         if (ACPI_FAILURE(mutex_status)) {
 263                                                 return_ACPI_STATUS
 264                                                     (mutex_status);
 265                                         }
 266                                 }
 267
 268                                 status =
 269                                     user_function(child_node, level, context,
 270                                                   return_value);
 271
 272                                 if (flags & ACPI_NS_WALK_UNLOCK) {
 273                                         mutex_status =
 274                                             acpi_ut_acquire_mutex
 275                                             (ACPI_MTX_NAMESPACE);
 276                                         if (ACPI_FAILURE(mutex_status)) {
 277                                                 return_ACPI_STATUS
 278                                                     (mutex_status);
 279                                         }
 280                                 }
 281
 282                                 switch (status) {
 283                                 case AE_OK:
 284                                 case AE_CTRL_DEPTH:
 285
 286                                         /* Just keep going */
 287                                         break;
 288
 289                                 case AE_CTRL_TERMINATE:
 290
 291                                         /* Exit now, with OK status */
 292
 293                                         return_ACPI_STATUS(AE_OK);
 294
 295                                 default:
 296
 297                                         /* All others are valid exceptions */
 298
 299                                         return_ACPI_STATUS(status);
 300                                 }
 301                         }
 302
 303                         /*
 304                          * Depth first search: Attempt to go down another level in the
 305                          * namespace if we are allowed to.  Don't go any further if we have
 306                          * reached the caller specified maximum depth or if the user
 307                          * function has specified that the maximum depth has been reached.
 308                          */
 309                         if ((level < max_depth) && (status != AE_CTRL_DEPTH)) {
 310                                 if (child_node->child) {
 311
 312                                         /* There is at least one child of this node, visit it */
 313
 314                                         level++;
 315                                         parent_node = child_node;
 316                                         child_node = NULL;
 317                                 }
 318                         }
 319                 } else {
 320                         /*
 321                          * No more children of this node (acpi_ns_get_next_node failed), go
 322                          * back upwards in the namespace tree to the node's parent.
 323                          */
 324                         level--;
 325                         child_node = parent_node;
 326                         parent_node = acpi_ns_get_parent_node(parent_node);
 327                 }
 328         }
 329
 330         /* Complete walk, not terminated by user function */
 331
 332         return_ACPI_STATUS(AE_OK);
 333 }