drivers/bus/acpi/parser/pswalk.c

   1 /******************************************************************************
   2  *
   3  * Module Name: pswalk - Parser routines to walk parsed op tree(s)
   4  *              $Revision$
   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         /* Check for a argument only if we are descending in the tree */
  65
  66         if (walk_state->next_op_info != NEXT_OP_UPWARD) {
  67                 /* Look for an argument or child of the current op */
  68
  69                 next = acpi_ps_get_arg (op, 0);
  70                 if (next) {
  71                         /* Still going downward in tree (Op is not completed yet) */
  72
  73                         walk_state->prev_op     = op;
  74                         walk_state->next_op     = next;
  75                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
  76
  77                         return (AE_OK);
  78                 }
  79
  80
  81                 /*
  82                  * No more children, this Op is complete.  Save Next and Parent
  83                  * in case the Op object gets deleted by the callback routine
  84                  */
  85
  86                 next    = op->next;
  87                 parent  = op->parent;
  88
  89                 status = ascending_callback (walk_state, op);
  90
  91                 /*
  92                  * If we are back to the starting point, the walk is complete.
  93                  */
  94                 if (op == walk_state->origin) {
  95                         /* Reached the point of origin, the walk is complete */
  96
  97                         walk_state->prev_op     = op;
  98                         walk_state->next_op     = NULL;
  99
 100                         return (status);
 101                 }
 102
 103                 /*
 104                  * Check for a sibling to the current op.  A sibling means
 105                  * we are still going "downward" in the tree.
 106                  */
 107
 108                 if (next) {
 109                         /* There is a sibling, it will be next */
 110
 111                         walk_state->prev_op     = op;
 112                         walk_state->next_op     = next;
 113                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 114
 115                         /* Continue downward */
 116
 117                         return (status);
 118                 }
 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
 133                 parent = op;
 134         }
 135
 136
 137         /*
 138          * Look for a sibling of the current Op's parent
 139          * Continue moving up the tree until we find a node that has not been
 140          * visited, or we get back to where we started.
 141          */
 142         while (parent) {
 143                 /* We are moving up the tree, therefore this parent Op is complete */
 144
 145                 grand_parent = parent->parent;
 146                 next        = parent->next;
 147
 148                 status = ascending_callback (walk_state, parent);
 149
 150                 /*
 151                  * If we are back to the starting point, the walk is complete.
 152                  */
 153                 if (parent == walk_state->origin) {
 154                         /* Reached the point of origin, the walk is complete */
 155
 156                         walk_state->prev_op     = parent;
 157                         walk_state->next_op     = NULL;
 158
 159                         return (status);
 160                 }
 161
 162                 /*
 163                  * If there is a sibling to this parent (it is not the starting point
 164                  * Op), then we will visit it.
 165                  */
 166                 if (next) {
 167                         /* found sibling of parent */
 168
 169                         walk_state->prev_op     = parent;
 170                         walk_state->next_op     = next;
 171                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 172
 173                         return (status);
 174                 }
 175
 176                 /* No siblings, no errors, just move up one more level in the tree */
 177
 178                 op                  = parent;
 179                 parent              = grand_parent;
 180                 walk_state->prev_op = op;
 181         }
 182
 183
 184         /* Got all the way to the top of the tree, we must be done! */
 185         /* However, the code should have terminated in the loop above */
 186
 187         walk_state->next_op     = NULL;
 188
 189         return (AE_OK);
 190 }
 191
 192
 193 /*******************************************************************************
 194  *
 195  * FUNCTION:    Acpi_ps_delete_completed_op
 196  *
 197  * PARAMETERS:  State           - Walk state
 198  *              Op              - Completed op
 199  *
 200  * RETURN:      AE_OK
 201  *
 202  * DESCRIPTION: Callback function for Acpi_ps_get_next_walk_op(). Used during
 203  *              Acpi_ps_delete_parse tree to delete Op objects when all sub-objects
 204  *              have been visited (and deleted.)
 205  *
 206  ******************************************************************************/
 207
 208 static ACPI_STATUS
 209 acpi_ps_delete_completed_op (
 210         ACPI_WALK_STATE         *state,
 211         ACPI_PARSE_OBJECT       *op)
 212 {
 213
 214         acpi_ps_free_op (op);
 215         return (AE_OK);
 216 }
 217
 218
 219 /*******************************************************************************
 220  *
 221  * FUNCTION:    Acpi_ps_delete_parse_tree
 222  *
 223  * PARAMETERS:  Subtree_root        - Root of tree (or subtree) to delete
 224  *
 225  * RETURN:      None
 226  *
 227  * DESCRIPTION: Delete a portion of or an entire parse tree.
 228  *
 229  ******************************************************************************/
 230
 231 void
 232 acpi_ps_delete_parse_tree (
 233         ACPI_PARSE_OBJECT       *subtree_root)
 234 {
 235         ACPI_WALK_STATE         *walk_state;
 236         ACPI_WALK_LIST          walk_list;
 237
 238
 239         if (!subtree_root) {
 240                 return;
 241         }
 242
 243         /* Create and initialize a new walk list */
 244
 245         walk_list.walk_state = NULL;
 246         walk_list.acquired_mutex_list.prev = NULL;
 247         walk_list.acquired_mutex_list.next = NULL;
 248
 249         walk_state = acpi_ds_create_walk_state (TABLE_ID_DSDT, NULL, NULL, &walk_list);
 250         if (!walk_state) {
 251                 return;
 252         }
 253
 254         walk_state->parser_state        = NULL;
 255         walk_state->parse_flags         = 0;
 256         walk_state->descending_callback = NULL;
 257         walk_state->ascending_callback  = NULL;
 258
 259
 260         walk_state->origin = subtree_root;
 261         walk_state->next_op = subtree_root;
 262
 263
 264         /* Head downward in the tree */
 265
 266         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 267
 268         /* Visit all nodes in the subtree */
 269
 270         while (walk_state->next_op) {
 271                 acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,
 272                                  acpi_ps_delete_completed_op);
 273         }
 274
 275         /* We are done with this walk */
 276
 277         acpi_aml_release_all_mutexes ((ACPI_OPERAND_OBJECT *) &walk_list.acquired_mutex_list);
 278         acpi_ds_delete_walk_state (walk_state);
 279
 280         return;
 281 }
 282
 283