drivers/bus/acpi/parser/pswalk.c

   1 /******************************************************************************
   2  *
   3  * Module Name: pswalk - Parser routines to walk parsed op tree(s)
   4  *              $Revision: 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
  29 #define _COMPONENT          ACPI_PARSER
  30          MODULE_NAME         ("pswalk")
  31
  32
  33 /*******************************************************************************
  34  *
  35  * FUNCTION:    Acpi_ps_get_next_walk_op
  36  *
  37  * PARAMETERS:  Walk_state          - Current state of the walk
  38  *              Op                  - Current Op to be walked
  39  *              Ascending_callback  - Procedure called when Op is complete
  40  *
  41  * RETURN:      Status
  42  *
  43  * DESCRIPTION: Get the next Op in a walk of the parse tree.
  44  *
  45  ******************************************************************************/
  46
  47 ACPI_STATUS
  48 acpi_ps_get_next_walk_op (
  49         ACPI_WALK_STATE         *walk_state,
  50         ACPI_PARSE_OBJECT       *op,
  51         ACPI_PARSE_UPWARDS      ascending_callback)
  52 {
  53         ACPI_PARSE_OBJECT       *next;
  54         ACPI_PARSE_OBJECT       *parent;
  55         ACPI_PARSE_OBJECT       *grand_parent;
  56         ACPI_STATUS             status;
  57
  58
  59         /* Check for a argument only if we are descending in the tree */
  60
  61         if (walk_state->next_op_info != NEXT_OP_UPWARD) {
  62                 /* Look for an argument or child of the current op */
  63
  64                 next = acpi_ps_get_arg (op, 0);
  65                 if (next) {
  66                         /* Still going downward in tree (Op is not completed yet) */
  67
  68                         walk_state->prev_op     = op;
  69                         walk_state->next_op     = next;
  70                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
  71
  72                         return (AE_OK);
  73                 }
  74
  75
  76                 /*
  77                  * No more children, this Op is complete.  Save Next and Parent
  78                  * in case the Op object gets deleted by the callback routine
  79                  */
  80
  81                 next    = op->next;
  82                 parent  = op->parent;
  83
  84                 status = ascending_callback (walk_state, op);
  85
  86                 /*
  87                  * If we are back to the starting point, the walk is complete.
  88                  */
  89                 if (op == walk_state->origin) {
  90                         /* Reached the point of origin, the walk is complete */
  91
  92                         walk_state->prev_op     = op;
  93                         walk_state->next_op     = NULL;
  94
  95                         return (status);
  96                 }
  97
  98                 /*
  99                  * Check for a sibling to the current op.  A sibling means
 100                  * we are still going "downward" in the tree.
 101                  */
 102
 103                 if (next) {
 104                         /* There is a sibling, it will be next */
 105
 106                         walk_state->prev_op     = op;
 107                         walk_state->next_op     = next;
 108                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 109
 110                         /* Continue downward */
 111
 112                         return (status);
 113                 }
 114
 115
 116                 /*
 117                  * Drop into the loop below because we are moving upwards in
 118                  * the tree
 119                  */
 120         }
 121
 122         else {
 123                 /*
 124                  * We are resuming a walk, and we were (are) going upward in the tree.
 125                  * So, we want to drop into the parent loop below.
 126                  */
 127
 128                 parent = op;
 129         }
 130
 131
 132         /*
 133          * Look for a sibling of the current Op's parent
 134          * Continue moving up the tree until we find a node that has not been
 135          * visited, or we get back to where we started.
 136          */
 137         while (parent) {
 138                 /* We are moving up the tree, therefore this parent Op is complete */
 139
 140                 grand_parent = parent->parent;
 141                 next        = parent->next;
 142
 143                 status = ascending_callback (walk_state, parent);
 144
 145                 /*
 146                  * If we are back to the starting point, the walk is complete.
 147                  */
 148                 if (parent == walk_state->origin) {
 149                         /* Reached the point of origin, the walk is complete */
 150
 151                         walk_state->prev_op     = parent;
 152                         walk_state->next_op     = NULL;
 153
 154                         return (status);
 155                 }
 156
 157                 /*
 158                  * If there is a sibling to this parent (it is not the starting point
 159                  * Op), then we will visit it.
 160                  */
 161                 if (next) {
 162                         /* found sibling of parent */
 163
 164                         walk_state->prev_op     = parent;
 165                         walk_state->next_op     = next;
 166                         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 167
 168                         return (status);
 169                 }
 170
 171                 /* No siblings, no errors, just move up one more level in the tree */
 172
 173                 op                  = parent;
 174                 parent              = grand_parent;
 175                 walk_state->prev_op = op;
 176         }
 177
 178
 179         /* Got all the way to the top of the tree, we must be done! */
 180         /* However, the code should have terminated in the loop above */
 181
 182         walk_state->next_op     = NULL;
 183
 184         return (AE_OK);
 185 }
 186
 187
 188 /*******************************************************************************
 189  *
 190  * FUNCTION:    Acpi_ps_delete_completed_op
 191  *
 192  * PARAMETERS:  State           - Walk state
 193  *              Op              - Completed op
 194  *
 195  * RETURN:      AE_OK
 196  *
 197  * DESCRIPTION: Callback function for Acpi_ps_get_next_walk_op(). Used during
 198  *              Acpi_ps_delete_parse tree to delete Op objects when all sub-objects
 199  *              have been visited (and deleted.)
 200  *
 201  ******************************************************************************/
 202
 203 static ACPI_STATUS
 204 acpi_ps_delete_completed_op (
 205         ACPI_WALK_STATE         *state,
 206         ACPI_PARSE_OBJECT       *op)
 207 {
 208
 209         acpi_ps_free_op (op);
 210         return (AE_OK);
 211 }
 212
 213
 214 /*******************************************************************************
 215  *
 216  * FUNCTION:    Acpi_ps_delete_parse_tree
 217  *
 218  * PARAMETERS:  Subtree_root        - Root of tree (or subtree) to delete
 219  *
 220  * RETURN:      None
 221  *
 222  * DESCRIPTION: Delete a portion of or an entire parse tree.
 223  *
 224  ******************************************************************************/
 225
 226 void
 227 acpi_ps_delete_parse_tree (
 228         ACPI_PARSE_OBJECT       *subtree_root)
 229 {
 230         ACPI_WALK_STATE         *walk_state;
 231         ACPI_WALK_LIST          walk_list;
 232
 233
 234         if (!subtree_root) {
 235                 return;
 236         }
 237
 238         /* Create and initialize a new walk list */
 239
 240         walk_list.walk_state = NULL;
 241         walk_list.acquired_mutex_list.prev = NULL;
 242         walk_list.acquired_mutex_list.next = NULL;
 243
 244         walk_state = acpi_ds_create_walk_state (TABLE_ID_DSDT, NULL, NULL, &walk_list);
 245         if (!walk_state) {
 246                 return;
 247         }
 248
 249         walk_state->parser_state        = NULL;
 250         walk_state->parse_flags         = 0;
 251         walk_state->descending_callback = NULL;
 252         walk_state->ascending_callback  = NULL;
 253
 254
 255         walk_state->origin = subtree_root;
 256         walk_state->next_op = subtree_root;
 257
 258
 259         /* Head downward in the tree */
 260
 261         walk_state->next_op_info = NEXT_OP_DOWNWARD;
 262
 263         /* Visit all nodes in the subtree */
 264
 265         while (walk_state->next_op) {
 266                 acpi_ps_get_next_walk_op (walk_state, walk_state->next_op,
 267                                  acpi_ps_delete_completed_op);
 268         }
 269
 270         /* We are done with this walk */
 271
 272         acpi_aml_release_all_mutexes ((ACPI_OPERAND_OBJECT *) &walk_list.acquired_mutex_list);
 273         acpi_ds_delete_walk_state (walk_state);
 274
 275         return;
 276 }
 277
 278