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1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.02/******************************************************************************3 *4 * Module Name: nswalk - Functions for walking the ACPI namespace5 *6 * Copyright (C) 2000 - 2023, Intel Corp.7 *8 *****************************************************************************/9 10#include <acpi/acpi.h>11#include "accommon.h"12#include "acnamesp.h"13 14#define _COMPONENT ACPI_NAMESPACE15ACPI_MODULE_NAME("nswalk")16 17/*******************************************************************************18 *19 * FUNCTION: acpi_ns_get_next_node20 *21 * PARAMETERS: parent_node - Parent node whose children we are22 * getting23 * child_node - Previous child that was found.24 * The NEXT child will be returned25 *26 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if27 * none is found.28 *29 * DESCRIPTION: Return the next peer node within the namespace. If Handle30 * is valid, Scope is ignored. Otherwise, the first node31 * within Scope is returned.32 *33 ******************************************************************************/34struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node35 *parent_node,36 struct acpi_namespace_node37 *child_node)38{39 ACPI_FUNCTION_ENTRY();40 41 if (!child_node) {42 43 /* It's really the parent's _scope_ that we want */44 45 return (parent_node->child);46 }47 48 /* Otherwise just return the next peer */49 50 return (child_node->peer);51}52 53/*******************************************************************************54 *55 * FUNCTION: acpi_ns_get_next_node_typed56 *57 * PARAMETERS: type - Type of node to be searched for58 * parent_node - Parent node whose children we are59 * getting60 * child_node - Previous child that was found.61 * The NEXT child will be returned62 *63 * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if64 * none is found.65 *66 * DESCRIPTION: Return the next peer node within the namespace. If Handle67 * is valid, Scope is ignored. Otherwise, the first node68 * within Scope is returned.69 *70 ******************************************************************************/71 72struct acpi_namespace_node *acpi_ns_get_next_node_typed(acpi_object_type type,73 struct74 acpi_namespace_node75 *parent_node,76 struct77 acpi_namespace_node78 *child_node)79{80 struct acpi_namespace_node *next_node = NULL;81 82 ACPI_FUNCTION_ENTRY();83 84 next_node = acpi_ns_get_next_node(parent_node, child_node);85 86 87 /* If any type is OK, we are done */88 89 if (type == ACPI_TYPE_ANY) {90 91 /* next_node is NULL if we are at the end-of-list */92 93 return (next_node);94 }95 96 /* Must search for the node -- but within this scope only */97 98 while (next_node) {99 100 /* If type matches, we are done */101 102 if (next_node->type == type) {103 return (next_node);104 }105 106 /* Otherwise, move on to the next peer node */107 108 next_node = next_node->peer;109 }110 111 /* Not found */112 113 return (NULL);114}115 116/*******************************************************************************117 *118 * FUNCTION: acpi_ns_walk_namespace119 *120 * PARAMETERS: type - acpi_object_type to search for121 * start_node - Handle in namespace where search begins122 * max_depth - Depth to which search is to reach123 * flags - Whether to unlock the NS before invoking124 * the callback routine125 * descending_callback - Called during tree descent126 * when an object of "Type" is found127 * ascending_callback - Called during tree ascent128 * when an object of "Type" is found129 * context - Passed to user function(s) above130 * return_value - from the user_function if terminated131 * early. Otherwise, returns NULL.132 * RETURNS: Status133 *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 callback function is called whenever a node that matches137 * the type parameter is found. If the callback function returns138 * a non-zero value, the search is terminated immediately and139 * this value is returned to the caller.140 *141 * The point of this procedure is to provide a generic namespace142 * walk routine that can be called from multiple places to143 * provide multiple services; the callback function(s) can be144 * tailored to each task, whether it is a print function,145 * a compare function, etc.146 *147 ******************************************************************************/148 149acpi_status150acpi_ns_walk_namespace(acpi_object_type type,151 acpi_handle start_node,152 u32 max_depth,153 u32 flags,154 acpi_walk_callback descending_callback,155 acpi_walk_callback ascending_callback,156 void *context, void **return_value)157{158 acpi_status status;159 acpi_status mutex_status;160 struct acpi_namespace_node *child_node;161 struct acpi_namespace_node *parent_node;162 acpi_object_type child_type;163 u32 level;164 u8 node_previously_visited = FALSE;165 166 ACPI_FUNCTION_TRACE(ns_walk_namespace);167 168 /* Special case for the namespace Root Node */169 170 if (start_node == ACPI_ROOT_OBJECT) {171 start_node = acpi_gbl_root_node;172 if (!start_node) {173 return_ACPI_STATUS(AE_NO_NAMESPACE);174 }175 }176 177 /* Null child means "get first node" */178 179 parent_node = start_node;180 child_node = acpi_ns_get_next_node(parent_node, NULL);181 child_type = ACPI_TYPE_ANY;182 level = 1;183 184 /*185 * Traverse the tree of nodes until we bubble back up to where we186 * started. When Level is zero, the loop is done because we have187 * bubbled up to (and passed) the original parent handle (start_entry)188 */189 while (level > 0 && child_node) {190 status = AE_OK;191 192 /* Found next child, get the type if we are not searching for ANY */193 194 if (type != ACPI_TYPE_ANY) {195 child_type = child_node->type;196 }197 198 /*199 * Ignore all temporary namespace nodes (created during control200 * method execution) unless told otherwise. These temporary nodes201 * can cause a race condition because they can be deleted during202 * the execution of the user function (if the namespace is203 * unlocked before invocation of the user function.) Only the204 * debugger namespace dump will examine the temporary nodes.205 */206 if ((child_node->flags & ANOBJ_TEMPORARY) &&207 !(flags & ACPI_NS_WALK_TEMP_NODES)) {208 status = AE_CTRL_DEPTH;209 }210 211 /* Type must match requested type */212 213 else if (child_type == type) {214 /*215 * Found a matching node, invoke the user callback function.216 * Unlock the namespace if flag is set.217 */218 if (flags & ACPI_NS_WALK_UNLOCK) {219 mutex_status =220 acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);221 if (ACPI_FAILURE(mutex_status)) {222 return_ACPI_STATUS(mutex_status);223 }224 }225 226 /*227 * Invoke the user function, either descending, ascending,228 * or both.229 */230 if (!node_previously_visited) {231 if (descending_callback) {232 status =233 descending_callback(child_node,234 level, context,235 return_value);236 }237 } else {238 if (ascending_callback) {239 status =240 ascending_callback(child_node,241 level, context,242 return_value);243 }244 }245 246 if (flags & ACPI_NS_WALK_UNLOCK) {247 mutex_status =248 acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);249 if (ACPI_FAILURE(mutex_status)) {250 return_ACPI_STATUS(mutex_status);251 }252 }253 254 switch (status) {255 case AE_OK:256 case AE_CTRL_DEPTH:257 258 /* Just keep going */259 break;260 261 case AE_CTRL_TERMINATE:262 263 /* Exit now, with OK status */264 265 return_ACPI_STATUS(AE_OK);266 267 default:268 269 /* All others are valid exceptions */270 271 return_ACPI_STATUS(status);272 }273 }274 275 /*276 * Depth first search: Attempt to go down another level in the277 * namespace if we are allowed to. Don't go any further if we have278 * reached the caller specified maximum depth or if the user279 * function has specified that the maximum depth has been reached.280 */281 if (!node_previously_visited &&282 (level < max_depth) && (status != AE_CTRL_DEPTH)) {283 if (child_node->child) {284 285 /* There is at least one child of this node, visit it */286 287 level++;288 parent_node = child_node;289 child_node =290 acpi_ns_get_next_node(parent_node, NULL);291 continue;292 }293 }294 295 /* No more children, re-visit this node */296 297 if (!node_previously_visited) {298 node_previously_visited = TRUE;299 continue;300 }301 302 /* No more children, visit peers */303 304 child_node = acpi_ns_get_next_node(parent_node, child_node);305 if (child_node) {306 node_previously_visited = FALSE;307 }308 309 /* No peers, re-visit parent */310 311 else {312 /*313 * No more children of this node (acpi_ns_get_next_node failed), go314 * back upwards in the namespace tree to the node's parent.315 */316 level--;317 child_node = parent_node;318 parent_node = parent_node->parent;319 320 node_previously_visited = TRUE;321 }322 }323 324 /* Complete walk, not terminated by user function */325 326 return_ACPI_STATUS(AE_OK);327}328