File: /usr/src/linux/drivers/acpi/parser/pswalk.c
1 /******************************************************************************
2 *
3 * Module Name: pswalk - Parser routines to walk parsed op tree(s)
4 * $Revision: 56 $
5 *
6 *****************************************************************************/
7
8 /*
9 * Copyright (C) 2000, 2001 R. Byron Moore
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or
14 * (at your option) any later version.
15 *
16 * This program is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 * GNU General Public License for more details.
20 *
21 * You should have received a copy of the GNU General Public License
22 * along with this program; if not, write to the Free Software
23 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 */
25
26
27 #include "acpi.h"
28 #include "amlcode.h"
29 #include "acparser.h"
30 #include "acdispat.h"
31 #include "acnamesp.h"
32 #include "acinterp.h"
33
34 #define _COMPONENT ACPI_PARSER
35 MODULE_NAME ("pswalk")
36
37
38 /*******************************************************************************
39 *
40 * FUNCTION: Acpi_ps_get_next_walk_op
41 *
42 * PARAMETERS: Walk_state - Current state of the walk
43 * Op - Current Op to be walked
44 * Ascending_callback - Procedure called when Op is complete
45 *
46 * RETURN: Status
47 *
48 * DESCRIPTION: Get the next Op in a walk of the parse tree.
49 *
50 ******************************************************************************/
51
52 acpi_status
53 acpi_ps_get_next_walk_op (
54 acpi_walk_state *walk_state,
55 acpi_parse_object *op,
56 acpi_parse_upwards ascending_callback)
57 {
58 acpi_parse_object *next;
59 acpi_parse_object *parent;
60 acpi_parse_object *grand_parent;
61 acpi_status status;
62
63
64 FUNCTION_TRACE_PTR ("Ps_get_next_walk_op", op);
65
66
67 /* Check for a argument only if we are descending in the tree */
68
69 if (walk_state->next_op_info != NEXT_OP_UPWARD) {
70 /* Look for an argument or child of the current op */
71
72 next = acpi_ps_get_arg (op, 0);
73 if (next) {
74 /* Still going downward in tree (Op is not completed yet) */
75
76 walk_state->prev_op = op;
77 walk_state->next_op = next;
78 walk_state->next_op_info = NEXT_OP_DOWNWARD;
79
80 return_ACPI_STATUS (AE_OK);
81 }
82
83
84 /*
85 * No more children, this Op is complete. Save Next and Parent
86 * in case the Op object gets deleted by the callback routine
87 */
88 next = op->next;
89 parent = op->parent;
90
91 status = ascending_callback (walk_state, op);
92
93 /*
94 * If we are back to the starting point, the walk is complete.
95 */
96 if (op == walk_state->origin) {
97 /* Reached the point of origin, the walk is complete */
98
99 walk_state->prev_op = op;
100 walk_state->next_op = NULL;
101
102 return_ACPI_STATUS (status);
103 }
104
105 /*
106 * Check for a sibling to the current op. A sibling means
107 * we are still going "downward" in the tree.
108 */
109 if (next) {
110 /* There is a sibling, it will be next */
111
112 walk_state->prev_op = op;
113 walk_state->next_op = next;
114 walk_state->next_op_info = NEXT_OP_DOWNWARD;
115
116 /* Continue downward */
117
118 return_ACPI_STATUS (status);
119 }
120
121 /*
122 * Drop into the loop below because we are moving upwards in
123 * the tree
124 */
125 }
126
127 else {
128 /*
129 * We are resuming a walk, and we were (are) going upward in the tree.
130 * So, we want to drop into the parent loop below.
131 */
132 parent = op;
133 }
134
135
136 /*
137 * Look for a sibling of the current Op's parent
138 * Continue moving up the tree until we find a node that has not been
139 * visited, or we get back to where we started.
140 */
141 while (parent) {
142 /* We are moving up the tree, therefore this parent Op is complete */
143
144 grand_parent = parent->parent;
145 next = parent->next;
146
147 status = ascending_callback (walk_state, parent);
148
149 /*
150 * If we are back to the starting point, the walk is complete.
151 */
152 if (parent == walk_state->origin) {
153 /* Reached the point of origin, the walk is complete */
154
155 walk_state->prev_op = parent;
156 walk_state->next_op = NULL;
157
158 return_ACPI_STATUS (status);
159 }
160
161 /*
162 * If there is a sibling to this parent (it is not the starting point
163 * Op), then we will visit it.
164 */
165 if (next) {
166 /* found sibling of parent */
167
168 walk_state->prev_op = parent;
169 walk_state->next_op = next;
170 walk_state->next_op_info = NEXT_OP_DOWNWARD;
171
172 return_ACPI_STATUS (status);
173 }
174
175 /* No siblings, no errors, just move up one more level in the tree */
176
177 op = parent;
178 parent = grand_parent;
179 walk_state->prev_op = op;
180 }
181
182
183 /* Got all the way to the top of the tree, we must be done! */
184 /* However, the code should have terminated in the loop above */
185
186 walk_state->next_op = NULL;
187
188 return_ACPI_STATUS (AE_OK);
189 }
190
191
192 /*******************************************************************************
193 *
194 * FUNCTION: Acpi_ps_delete_completed_op
195 *
196 * PARAMETERS: State - Walk state
197 * Op - Completed op
198 *
199 * RETURN: AE_OK
200 *
201 * DESCRIPTION: Callback function for Acpi_ps_get_next_walk_op(). Used during
202 * Acpi_ps_delete_parse tree to delete Op objects when all sub-objects
203 * have been visited (and deleted.)
204 *
205 ******************************************************************************/
206
207 static acpi_status
208 acpi_ps_delete_completed_op (
209 acpi_walk_state *state,
210 acpi_parse_object *op)
211 {
212
213 acpi_ps_free_op (op);
214 return (AE_OK);
215 }
216
217
218 /*******************************************************************************
219 *
220 * FUNCTION: Acpi_ps_delete_parse_tree
221 *
222 * PARAMETERS: Subtree_root - Root of tree (or subtree) to delete
223 *
224 * RETURN: None
225 *
226 * DESCRIPTION: Delete a portion of or an entire parse tree.
227 *
228 ******************************************************************************/
229
230 void
231 acpi_ps_delete_parse_tree (
232 acpi_parse_object *subtree_root)
233 {
234 acpi_walk_state *walk_state;
235 acpi_walk_list walk_list;
236
237
238 FUNCTION_TRACE_PTR ("Ps_delete_parse_tree", subtree_root);
239
240
241 if (!subtree_root) {
242 return_VOID;
243 }
244
245 /* Create and initialize a new walk list */
246
247 walk_list.walk_state = NULL;
248 walk_list.acquired_mutex_list.prev = NULL;
249 walk_list.acquired_mutex_list.next = NULL;
250
251 walk_state = acpi_ds_create_walk_state (TABLE_ID_DSDT, NULL, NULL, &walk_list);
252 if (!walk_state) {
253 return_VOID;
254 }
255
256 walk_state->parser_state = NULL;
257 walk_state->parse_flags = 0;
258 walk_state->descending_callback = NULL;
259 walk_state->ascending_callback = NULL;
260
261
262 walk_state->origin = subtree_root;
263 walk_state->next_op = subtree_root;
264
265
266 /* Head downward in the tree */
267
268 walk_state->next_op_info = NEXT_OP_DOWNWARD;
269
270 /* Visit all nodes in the subtree */
271
272 while (walk_state->next_op) {
273 acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,
274 acpi_ps_delete_completed_op);
275 }
276
277 /* We are done with this walk */
278
279 acpi_ex_release_all_mutexes ((acpi_operand_object *) &walk_list.acquired_mutex_list);
280 acpi_ds_delete_walk_state (walk_state);
281
282 return_VOID;
283 }
284
285
286