1 /******************************************************************************
2 *
3 * Module Name: pswalk - Parser routines to walk parsed op tree(s)
4 *
5 *****************************************************************************/
6
7 /*
8 * Copyright (C) 2000 - 2004, 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
45 #include <acpi/acpi.h>
46 #include <acpi/acparser.h>
47 #include <acpi/acdispat.h>
48
49 #define _COMPONENT ACPI_PARSER
50 ACPI_MODULE_NAME ("pswalk")
51
52
53 /*******************************************************************************
54 *
55 * FUNCTION: acpi_ps_get_next_walk_op
56 *
57 * PARAMETERS: walk_state - Current state of the walk
58 * Op - Current Op to be walked
59 * ascending_callback - Procedure called when Op is complete
60 *
61 * RETURN: Status
62 *
63 * DESCRIPTION: Get the next Op in a walk of the parse tree.
64 *
65 ******************************************************************************/
66
67 acpi_status
acpi_ps_get_next_walk_op(struct acpi_walk_state * walk_state,union acpi_parse_object * op,acpi_parse_upwards ascending_callback)68 acpi_ps_get_next_walk_op (
69 struct acpi_walk_state *walk_state,
70 union acpi_parse_object *op,
71 acpi_parse_upwards ascending_callback)
72 {
73 union acpi_parse_object *next;
74 union acpi_parse_object *parent;
75 union acpi_parse_object *grand_parent;
76 acpi_status status;
77
78
79 ACPI_FUNCTION_TRACE_PTR ("ps_get_next_walk_op", op);
80
81
82 /* Check for a argument only if we are descending in the tree */
83
84 if (walk_state->next_op_info != ACPI_NEXT_OP_UPWARD) {
85 /* Look for an argument or child of the current op */
86
87 next = acpi_ps_get_arg (op, 0);
88 if (next) {
89 /* Still going downward in tree (Op is not completed yet) */
90
91 walk_state->prev_op = op;
92 walk_state->next_op = next;
93 walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;
94
95 return_ACPI_STATUS (AE_OK);
96 }
97
98 /*
99 * No more children, this Op is complete. Save Next and Parent
100 * in case the Op object gets deleted by the callback routine
101 */
102 next = op->common.next;
103 parent = op->common.parent;
104
105 walk_state->op = op;
106 walk_state->op_info = acpi_ps_get_opcode_info (op->common.aml_opcode);
107 walk_state->opcode = op->common.aml_opcode;
108
109 status = ascending_callback (walk_state);
110
111 /*
112 * If we are back to the starting point, the walk is complete.
113 */
114 if (op == walk_state->origin) {
115 /* Reached the point of origin, the walk is complete */
116
117 walk_state->prev_op = op;
118 walk_state->next_op = NULL;
119
120 return_ACPI_STATUS (status);
121 }
122
123 /*
124 * Check for a sibling to the current op. A sibling means
125 * we are still going "downward" in the tree.
126 */
127 if (next) {
128 /* There is a sibling, it will be next */
129
130 walk_state->prev_op = op;
131 walk_state->next_op = next;
132 walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;
133
134 /* Continue downward */
135
136 return_ACPI_STATUS (status);
137 }
138
139 /*
140 * Drop into the loop below because we are moving upwards in
141 * the tree
142 */
143 }
144 else {
145 /*
146 * We are resuming a walk, and we were (are) going upward in the tree.
147 * So, we want to drop into the parent loop below.
148 */
149 parent = op;
150 }
151
152 /*
153 * Look for a sibling of the current Op's parent
154 * Continue moving up the tree until we find a node that has not been
155 * visited, or we get back to where we started.
156 */
157 while (parent) {
158 /* We are moving up the tree, therefore this parent Op is complete */
159
160 grand_parent = parent->common.parent;
161 next = parent->common.next;
162
163 walk_state->op = parent;
164 walk_state->op_info = acpi_ps_get_opcode_info (parent->common.aml_opcode);
165 walk_state->opcode = parent->common.aml_opcode;
166
167 status = ascending_callback (walk_state);
168
169 /*
170 * If we are back to the starting point, the walk is complete.
171 */
172 if (parent == walk_state->origin) {
173 /* Reached the point of origin, the walk is complete */
174
175 walk_state->prev_op = parent;
176 walk_state->next_op = NULL;
177
178 return_ACPI_STATUS (status);
179 }
180
181 /*
182 * If there is a sibling to this parent (it is not the starting point
183 * Op), then we will visit it.
184 */
185 if (next) {
186 /* found sibling of parent */
187
188 walk_state->prev_op = parent;
189 walk_state->next_op = next;
190 walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;
191
192 return_ACPI_STATUS (status);
193 }
194
195 /* No siblings, no errors, just move up one more level in the tree */
196
197 op = parent;
198 parent = grand_parent;
199 walk_state->prev_op = op;
200 }
201
202
203 /*
204 * Got all the way to the top of the tree, we must be done!
205 * However, the code should have terminated in the loop above
206 */
207 walk_state->next_op = NULL;
208
209 return_ACPI_STATUS (AE_OK);
210 }
211
212
213 /*******************************************************************************
214 *
215 * FUNCTION: acpi_ps_delete_completed_op
216 *
217 * PARAMETERS: State - Walk state
218 * Op - Completed op
219 *
220 * RETURN: AE_OK
221 *
222 * DESCRIPTION: Callback function for acpi_ps_get_next_walk_op(). Used during
223 * acpi_ps_delete_parse tree to delete Op objects when all sub-objects
224 * have been visited (and deleted.)
225 *
226 ******************************************************************************/
227
228 acpi_status
acpi_ps_delete_completed_op(struct acpi_walk_state * walk_state)229 acpi_ps_delete_completed_op (
230 struct acpi_walk_state *walk_state)
231 {
232
233 acpi_ps_free_op (walk_state->op);
234 return (AE_OK);
235 }
236
237
238 /*******************************************************************************
239 *
240 * FUNCTION: acpi_ps_delete_parse_tree
241 *
242 * PARAMETERS: subtree_root - Root of tree (or subtree) to delete
243 *
244 * RETURN: None
245 *
246 * DESCRIPTION: Delete a portion of or an entire parse tree.
247 *
248 ******************************************************************************/
249
250 void
acpi_ps_delete_parse_tree(union acpi_parse_object * subtree_root)251 acpi_ps_delete_parse_tree (
252 union acpi_parse_object *subtree_root)
253 {
254 struct acpi_walk_state *walk_state;
255 struct acpi_thread_state *thread;
256 acpi_status status;
257
258
259 ACPI_FUNCTION_TRACE_PTR ("ps_delete_parse_tree", subtree_root);
260
261
262 if (!subtree_root) {
263 return_VOID;
264 }
265
266 /* Create and initialize a new walk list */
267
268 thread = acpi_ut_create_thread_state ();
269 if (!thread) {
270 return_VOID;
271 }
272
273 walk_state = acpi_ds_create_walk_state (0, NULL, NULL, thread);
274 if (!walk_state) {
275 return_VOID;
276 }
277
278 walk_state->parse_flags = 0;
279 walk_state->descending_callback = NULL;
280 walk_state->ascending_callback = NULL;
281
282 walk_state->origin = subtree_root;
283 walk_state->next_op = subtree_root;
284
285 /* Head downward in the tree */
286
287 walk_state->next_op_info = ACPI_NEXT_OP_DOWNWARD;
288
289 /* Visit all nodes in the subtree */
290
291 while (walk_state->next_op) {
292 status = acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,
293 acpi_ps_delete_completed_op);
294 if (ACPI_FAILURE (status)) {
295 break;
296 }
297 }
298
299 /* We are done with this walk */
300
301 acpi_ut_delete_generic_state (ACPI_CAST_PTR (union acpi_generic_state, thread));
302 acpi_ds_delete_walk_state (walk_state);
303
304 return_VOID;
305 }
306
307
308