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0001 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 0002 /****************************************************************************** 0003 * 0004 * Module Name: nswalk - Functions for walking the ACPI namespace 0005 * 0006 * Copyright (C) 2000 - 2022, Intel Corp. 0007 * 0008 *****************************************************************************/ 0009 0010 #include <acpi/acpi.h> 0011 #include "accommon.h" 0012 #include "acnamesp.h" 0013 0014 #define _COMPONENT ACPI_NAMESPACE 0015 ACPI_MODULE_NAME("nswalk") 0016 0017 /******************************************************************************* 0018 * 0019 * FUNCTION: acpi_ns_get_next_node 0020 * 0021 * PARAMETERS: parent_node - Parent node whose children we are 0022 * getting 0023 * child_node - Previous child that was found. 0024 * The NEXT child will be returned 0025 * 0026 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if 0027 * none is found. 0028 * 0029 * DESCRIPTION: Return the next peer node within the namespace. If Handle 0030 * is valid, Scope is ignored. Otherwise, the first node 0031 * within Scope is returned. 0032 * 0033 ******************************************************************************/ 0034 struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node 0035 *parent_node, 0036 struct acpi_namespace_node 0037 *child_node) 0038 { 0039 ACPI_FUNCTION_ENTRY(); 0040 0041 if (!child_node) { 0042 0043 /* It's really the parent's _scope_ that we want */ 0044 0045 return (parent_node->child); 0046 } 0047 0048 /* Otherwise just return the next peer */ 0049 0050 return (child_node->peer); 0051 } 0052 0053 /******************************************************************************* 0054 * 0055 * FUNCTION: acpi_ns_get_next_node_typed 0056 * 0057 * PARAMETERS: type - Type of node to be searched for 0058 * parent_node - Parent node whose children we are 0059 * getting 0060 * child_node - Previous child that was found. 0061 * The NEXT child will be returned 0062 * 0063 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if 0064 * none is found. 0065 * 0066 * DESCRIPTION: Return the next peer node within the namespace. If Handle 0067 * is valid, Scope is ignored. Otherwise, the first node 0068 * within Scope is returned. 0069 * 0070 ******************************************************************************/ 0071 0072 struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type, 0073 struct 0074 acpi_namespace_node 0075 *parent_node, 0076 struct 0077 acpi_namespace_node 0078 *child_node) 0079 { 0080 struct acpi_namespace_node *next_node = NULL; 0081 0082 ACPI_FUNCTION_ENTRY(); 0083 0084 next_node = acpi_ns_get_next_node(parent_node, child_node); 0085 0086 0087 /* If any type is OK, we are done */ 0088 0089 if (type == ACPI_TYPE_ANY) { 0090 0091 /* next_node is NULL if we are at the end-of-list */ 0092 0093 return (next_node); 0094 } 0095 0096 /* Must search for the node -- but within this scope only */ 0097 0098 while (next_node) { 0099 0100 /* If type matches, we are done */ 0101 0102 if (next_node->type == type) { 0103 return (next_node); 0104 } 0105 0106 /* Otherwise, move on to the next peer node */ 0107 0108 next_node = next_node->peer; 0109 } 0110 0111 /* Not found */ 0112 0113 return (NULL); 0114 } 0115 0116 /******************************************************************************* 0117 * 0118 * FUNCTION: acpi_ns_walk_namespace 0119 * 0120 * PARAMETERS: type - acpi_object_type to search for 0121 * start_node - Handle in namespace where search begins 0122 * max_depth - Depth to which search is to reach 0123 * flags - Whether to unlock the NS before invoking 0124 * the callback routine 0125 * descending_callback - Called during tree descent 0126 * when an object of "Type" is found 0127 * ascending_callback - Called during tree ascent 0128 * when an object of "Type" is found 0129 * context - Passed to user function(s) above 0130 * return_value - from the user_function if terminated 0131 * early. Otherwise, returns NULL. 0132 * RETURNS: Status 0133 * 0134 * DESCRIPTION: Performs a modified depth-first walk of the namespace tree, 0135 * starting (and ending) at the node specified by start_handle. 0136 * The callback function is called whenever a node that matches 0137 * the type parameter is found. If the callback function returns 0138 * a non-zero value, the search is terminated immediately and 0139 * this value is returned to the caller. 0140 * 0141 * The point of this procedure is to provide a generic namespace 0142 * walk routine that can be called from multiple places to 0143 * provide multiple services; the callback function(s) can be 0144 * tailored to each task, whether it is a print function, 0145 * a compare function, etc. 0146 * 0147 ******************************************************************************/ 0148 0149 acpi_status 0150 acpi_ns_walk_namespace(acpi_object_type type, 0151 acpi_handle start_node, 0152 u32 max_depth, 0153 u32 flags, 0154 acpi_walk_callback descending_callback, 0155 acpi_walk_callback ascending_callback, 0156 void *context, void **return_value) 0157 { 0158 acpi_status status; 0159 acpi_status mutex_status; 0160 struct acpi_namespace_node *child_node; 0161 struct acpi_namespace_node *parent_node; 0162 acpi_object_type child_type; 0163 u32 level; 0164 u8 node_previously_visited = FALSE; 0165 0166 ACPI_FUNCTION_TRACE(ns_walk_namespace); 0167 0168 /* Special case for the namespace Root Node */ 0169 0170 if (start_node == ACPI_ROOT_OBJECT) { 0171 start_node = acpi_gbl_root_node; 0172 if (!start_node) { 0173 return_ACPI_STATUS(AE_NO_NAMESPACE); 0174 } 0175 } 0176 0177 /* Null child means "get first node" */ 0178 0179 parent_node = start_node; 0180 child_node = acpi_ns_get_next_node(parent_node, NULL); 0181 child_type = ACPI_TYPE_ANY; 0182 level = 1; 0183 0184 /* 0185 * Traverse the tree of nodes until we bubble back up to where we 0186 * started. When Level is zero, the loop is done because we have 0187 * bubbled up to (and passed) the original parent handle (start_entry) 0188 */ 0189 while (level > 0 && child_node) { 0190 status = AE_OK; 0191 0192 /* Found next child, get the type if we are not searching for ANY */ 0193 0194 if (type != ACPI_TYPE_ANY) { 0195 child_type = child_node->type; 0196 } 0197 0198 /* 0199 * Ignore all temporary namespace nodes (created during control 0200 * method execution) unless told otherwise. These temporary nodes 0201 * can cause a race condition because they can be deleted during 0202 * the execution of the user function (if the namespace is 0203 * unlocked before invocation of the user function.) Only the 0204 * debugger namespace dump will examine the temporary nodes. 0205 */ 0206 if ((child_node->flags & ANOBJ_TEMPORARY) && 0207 !(flags & ACPI_NS_WALK_TEMP_NODES)) { 0208 status = AE_CTRL_DEPTH; 0209 } 0210 0211 /* Type must match requested type */ 0212 0213 else if (child_type == type) { 0214 /* 0215 * Found a matching node, invoke the user callback function. 0216 * Unlock the namespace if flag is set. 0217 */ 0218 if (flags & ACPI_NS_WALK_UNLOCK) { 0219 mutex_status = 0220 acpi_ut_release_mutex(ACPI_MTX_NAMESPACE); 0221 if (ACPI_FAILURE(mutex_status)) { 0222 return_ACPI_STATUS(mutex_status); 0223 } 0224 } 0225 0226 /* 0227 * Invoke the user function, either descending, ascending, 0228 * or both. 0229 */ 0230 if (!node_previously_visited) { 0231 if (descending_callback) { 0232 status = 0233 descending_callback(child_node, 0234 level, context, 0235 return_value); 0236 } 0237 } else { 0238 if (ascending_callback) { 0239 status = 0240 ascending_callback(child_node, 0241 level, context, 0242 return_value); 0243 } 0244 } 0245 0246 if (flags & ACPI_NS_WALK_UNLOCK) { 0247 mutex_status = 0248 acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE); 0249 if (ACPI_FAILURE(mutex_status)) { 0250 return_ACPI_STATUS(mutex_status); 0251 } 0252 } 0253 0254 switch (status) { 0255 case AE_OK: 0256 case AE_CTRL_DEPTH: 0257 0258 /* Just keep going */ 0259 break; 0260 0261 case AE_CTRL_TERMINATE: 0262 0263 /* Exit now, with OK status */ 0264 0265 return_ACPI_STATUS(AE_OK); 0266 0267 default: 0268 0269 /* All others are valid exceptions */ 0270 0271 return_ACPI_STATUS(status); 0272 } 0273 } 0274 0275 /* 0276 * Depth first search: Attempt to go down another level in the 0277 * namespace if we are allowed to. Don't go any further if we have 0278 * reached the caller specified maximum depth or if the user 0279 * function has specified that the maximum depth has been reached. 0280 */ 0281 if (!node_previously_visited && 0282 (level < max_depth) && (status != AE_CTRL_DEPTH)) { 0283 if (child_node->child) { 0284 0285 /* There is at least one child of this node, visit it */ 0286 0287 level++; 0288 parent_node = child_node; 0289 child_node = 0290 acpi_ns_get_next_node(parent_node, NULL); 0291 continue; 0292 } 0293 } 0294 0295 /* No more children, re-visit this node */ 0296 0297 if (!node_previously_visited) { 0298 node_previously_visited = TRUE; 0299 continue; 0300 } 0301 0302 /* No more children, visit peers */ 0303 0304 child_node = acpi_ns_get_next_node(parent_node, child_node); 0305 if (child_node) { 0306 node_previously_visited = FALSE; 0307 } 0308 0309 /* No peers, re-visit parent */ 0310 0311 else { 0312 /* 0313 * No more children of this node (acpi_ns_get_next_node failed), go 0314 * back upwards in the namespace tree to the node's parent. 0315 */ 0316 level--; 0317 child_node = parent_node; 0318 parent_node = parent_node->parent; 0319 0320 node_previously_visited = TRUE; 0321 } 0322 } 0323 0324 /* Complete walk, not terminated by user function */ 0325 0326 return_ACPI_STATUS(AE_OK); 0327 }
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