1 | // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 |
2 | /****************************************************************************** |
3 | * |
4 | * Module Name: nswalk - Functions for walking the ACPI namespace |
5 | * |
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_NAMESPACE |
15 | ACPI_MODULE_NAME("nswalk" ) |
16 | |
17 | /******************************************************************************* |
18 | * |
19 | * FUNCTION: acpi_ns_get_next_node |
20 | * |
21 | * PARAMETERS: parent_node - Parent node whose children we are |
22 | * getting |
23 | * child_node - Previous child that was found. |
24 | * The NEXT child will be returned |
25 | * |
26 | * RETURN: struct acpi_namespace_node - Pointer to the NEXT child or NULL if |
27 | * none is found. |
28 | * |
29 | * DESCRIPTION: Return the next peer node within the namespace. If Handle |
30 | * is valid, Scope is ignored. Otherwise, the first node |
31 | * within Scope is returned. |
32 | * |
33 | ******************************************************************************/ |
34 | struct acpi_namespace_node *acpi_ns_get_next_node(struct acpi_namespace_node |
35 | *parent_node, |
36 | struct acpi_namespace_node |
37 | *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_typed |
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 *acpi_ns_get_next_node_typed(acpi_object_type type, |
73 | struct |
74 | acpi_namespace_node |
75 | *parent_node, |
76 | struct |
77 | acpi_namespace_node |
78 | *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_namespace |
119 | * |
120 | * PARAMETERS: type - acpi_object_type to search for |
121 | * start_node - Handle in namespace where search begins |
122 | * max_depth - Depth to which search is to reach |
123 | * flags - Whether to unlock the NS before invoking |
124 | * the callback routine |
125 | * descending_callback - Called during tree descent |
126 | * when an object of "Type" is found |
127 | * ascending_callback - Called during tree ascent |
128 | * when an object of "Type" is found |
129 | * context - Passed to user function(s) above |
130 | * return_value - from the user_function if terminated |
131 | * early. 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 callback function is called whenever a node that matches |
137 | * the type parameter is found. If the callback function returns |
138 | * a non-zero value, the search is terminated immediately and |
139 | * this 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 callback function(s) can be |
144 | * tailored to each task, whether it is a print function, |
145 | * a compare 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 | 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 we |
186 | * started. When Level is zero, the loop is done because we have |
187 | * 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 control |
200 | * method execution) unless told otherwise. These temporary nodes |
201 | * can cause a race condition because they can be deleted during |
202 | * the execution of the user function (if the namespace is |
203 | * unlocked before invocation of the user function.) Only the |
204 | * 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 the |
277 | * namespace if we are allowed to. Don't go any further if we have |
278 | * reached the caller specified maximum depth or if the user |
279 | * 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), go |
314 | * 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 | |