drivers/acpi/parser/pswalk.c

   1 /******************************************************************************
   2  *
   3  * Module Name: pswalk - Parser routines to walk parsed op tree(s)
   4  *              $Revision: 1.1.1.1 $
   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                 walk_state->op    = op;
  92                 walk_state->op_info = acpi_ps_get_opcode_info (op->opcode);
  93                 walk_state->opcode = op->opcode;
  94
  95                 status = ascending_callback (walk_state);
  96
  97                 /*
  98                  * If we are back to the starting point, the walk is complete.
  99                  */
 100                 if (op == walk_state->origin) {
 101                         /* Reached the point of origin, the walk is complete */
 102
 103                         walk_state->prev_op     = op;
 104                         walk_state->next_op     = NULL;
 105
 106                         return_ACPI_STATUS (status);
 107                 }
 108
 109                 /*
 110                  * Check for a sibling to the current op.  A sibling means
 111                  * we are still going "downward" in the tree.
 112                  */
 113                 if (next) {
 114                         /* There is a sibling, it will be next */
 115
 116                         walk_state->prev_op     = op;
 117                         walk_state->next_op     = next;
 118                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 119
 120                         /* Continue downward */
 121
 122                         return_ACPI_STATUS (status);
 123                 }
 124
 125                 /*
 126                  * Drop into the loop below because we are moving upwards in
 127                  * the tree
 128                  */
 129         }
 130
 131         else {
 132                 /*
 133                  * We are resuming a walk, and we were (are) going upward in the tree.
 134                  * So, we want to drop into the parent loop below.
 135                  */
 136                 parent = op;
 137         }
 138
 139
 140         /*
 141          * Look for a sibling of the current Op's parent
 142          * Continue moving up the tree until we find a node that has not been
 143          * visited, or we get back to where we started.
 144          */
 145         while (parent) {
 146                 /* We are moving up the tree, therefore this parent Op is complete */
 147
 148                 grand_parent = parent->parent;
 149                 next        = parent->next;
 150
 151                 walk_state->op    = parent;
 152                 walk_state->op_info = acpi_ps_get_opcode_info (parent->opcode);
 153                 walk_state->opcode = parent->opcode;
 154
 155                 status = ascending_callback (walk_state);
 156
 157                 /*
 158                  * If we are back to the starting point, the walk is complete.
 159                  */
 160                 if (parent == walk_state->origin) {
 161                         /* Reached the point of origin, the walk is complete */
 162
 163                         walk_state->prev_op     = parent;
 164                         walk_state->next_op     = NULL;
 165
 166                         return_ACPI_STATUS (status);
 167                 }
 168
 169                 /*
 170                  * If there is a sibling to this parent (it is not the starting point
 171                  * Op), then we will visit it.
 172                  */
 173                 if (next) {
 174                         /* found sibling of parent */
 175
 176                         walk_state->prev_op     = parent;
 177                         walk_state->next_op     = next;
 178                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 179
 180                         return_ACPI_STATUS (status);
 181                 }
 182
 183                 /* No siblings, no errors, just move up one more level in the tree */
 184
 185                 op                  = parent;
 186                 parent              = grand_parent;
 187                 walk_state->prev_op = op;
 188         }
 189
 190
 191         /* Got all the way to the top of the tree, we must be done! */
 192         /* However, the code should have terminated in the loop above */
 193
 194         walk_state->next_op     = NULL;
 195
 196         return_ACPI_STATUS (AE_OK);
 197 }
 198
 199
 200 /*******************************************************************************
 201  *
 202  * FUNCTION:    Acpi_ps_delete_completed_op
 203  *
 204  * PARAMETERS:  State           - Walk state
 205  *              Op              - Completed op
 206  *
 207  * RETURN:      AE_OK
 208  *
 209  * DESCRIPTION: Callback function for Acpi_ps_get_next_walk_op(). Used during
 210  *              Acpi_ps_delete_parse tree to delete Op objects when all sub-objects
 211  *              have been visited (and deleted.)
 212  *
 213  ******************************************************************************/
 214
 215 static acpi_status
 216 acpi_ps_delete_completed_op (
 217         acpi_walk_state         *walk_state)
 218 {
 219
 220         acpi_ps_free_op (walk_state->op);
 221         return (AE_OK);
 222 }
 223
 224
 225 /*******************************************************************************
 226  *
 227  * FUNCTION:    Acpi_ps_delete_parse_tree
 228  *
 229  * PARAMETERS:  Subtree_root        - Root of tree (or subtree) to delete
 230  *
 231  * RETURN:      None
 232  *
 233  * DESCRIPTION: Delete a portion of or an entire parse tree.
 234  *
 235  ******************************************************************************/
 236
 237 void
 238 acpi_ps_delete_parse_tree (
 239         acpi_parse_object       *subtree_root)
 240 {
 241         acpi_walk_state         *walk_state;
 242         acpi_walk_list          walk_list;
 243
 244
 245         FUNCTION_TRACE_PTR ("Ps_delete_parse_tree", subtree_root);
 246
 247
 248         if (!subtree_root) {
 249                 return_VOID;
 250         }
 251
 252         /* Create and initialize a new walk list */
 253
 254         walk_list.walk_state = NULL;
 255         walk_list.acquired_mutex_list.prev = NULL;
 256         walk_list.acquired_mutex_list.next = NULL;
 257
 258         walk_state = acpi_ds_create_walk_state (TABLE_ID_DSDT, NULL, NULL, &walk_list);
 259         if (!walk_state) {
 260                 return_VOID;
 261         }
 262
 263         walk_state->parse_flags         = 0;
 264         walk_state->descending_callback = NULL;
 265         walk_state->ascending_callback  = NULL;
 266
 267
 268         walk_state->origin = subtree_root;
 269         walk_state->next_op = subtree_root;
 270
 271
 272         /* Head downward in the tree */
 273
 274         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 275
 276         /* Visit all nodes in the subtree */
 277
 278         while (walk_state->next_op) {
 279                 acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,
 280                                  acpi_ps_delete_completed_op);
 281         }
 282
 283         /* We are done with this walk */
 284
 285         acpi_ex_release_all_mutexes ((acpi_operand_object *) &walk_list.acquired_mutex_list);
 286         acpi_ds_delete_walk_state (walk_state);
 287
 288         return_VOID;
 289 }
 290
 291