drivers/acpi/parser/pswalk.c

   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
  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
 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
 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