drivers/bus/acpi/executer/ammutex.c

   1
   2 /******************************************************************************
   3  *
   4  * Module Name: ammutex - ASL Mutex Acquire/Release functions
   5  *              $Revision$
   6  *
   7  *****************************************************************************/
   8
   9 /*
  10  *  Copyright (C) 2000, 2001 R. Byron Moore
  11  *
  12  *  This program is free software; you can redistribute it and/or modify
  13  *  it under the terms of the GNU General Public License as published by
  14  *  the Free Software Foundation; either version 2 of the License, or
  15  *  (at your option) any later version.
  16  *
  17  *  This program is distributed in the hope that it will be useful,
  18  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  *  GNU General Public License for more details.
  21  *
  22  *  You should have received a copy of the GNU General Public License
  23  *  along with this program; if not, write to the Free Software
  24  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25  */
  26
  27
  28 #include "acpi.h"
  29 #include "acinterp.h"
  30 #include "acnamesp.h"
  31 #include "achware.h"
  32 #include "acevents.h"
  33
  34 #define _COMPONENT          ACPI_EXECUTER
  35          MODULE_NAME         ("ammutex")
  36
  37
  38 /*******************************************************************************
  39  *
  40  * FUNCTION:    Acpi_aml_unlink_mutex
  41  *
  42  * PARAMETERS:  *Obj_desc           - The mutex to be unlinked
  43  *
  44  * RETURN:      Status
  45  *
  46  * DESCRIPTION: Remove a mutex from the "Acquired_mutex" list
  47  *
  48  ******************************************************************************/
  49
  50 void
  51 acpi_aml_unlink_mutex (
  52         ACPI_OPERAND_OBJECT     *obj_desc)
  53 {
  54
  55         if (obj_desc->mutex.next) {
  56                 (obj_desc->mutex.next)->mutex.prev = obj_desc->mutex.prev;
  57         }
  58         if (obj_desc->mutex.prev) {
  59                 (obj_desc->mutex.prev)->mutex.next = obj_desc->mutex.next;
  60         }
  61 }
  62
  63
  64 /*******************************************************************************
  65  *
  66  * FUNCTION:    Acpi_aml_link_mutex
  67  *
  68  * PARAMETERS:  *Obj_desc           - The mutex to be linked
  69  *              *List_head          - head of the "Acquired_mutex" list
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Add a mutex to the "Acquired_mutex" list for this walk
  74  *
  75  ******************************************************************************/
  76
  77 void
  78 acpi_aml_link_mutex (
  79         ACPI_OPERAND_OBJECT     *obj_desc,
  80         ACPI_OPERAND_OBJECT     *list_head)
  81 {
  82
  83         /* This object will be the first object in the list */
  84
  85         obj_desc->mutex.prev = list_head;
  86         obj_desc->mutex.next = list_head->mutex.next;
  87
  88         /* Update old first object to point back to this object */
  89
  90         if (list_head->mutex.next) {
  91                 (list_head->mutex.next)->mutex.prev = obj_desc;
  92         }
  93
  94         /* Update list head */
  95
  96         list_head->mutex.next = obj_desc;
  97 }
  98
  99
 100 /*******************************************************************************
 101  *
 102  * FUNCTION:    Acpi_aml_acquire_mutex
 103  *
 104  * PARAMETERS:  *Time_desc          - The 'time to delay' object descriptor
 105  *              *Obj_desc           - The object descriptor for this op
 106  *
 107  * RETURN:      Status
 108  *
 109  * DESCRIPTION: Acquire an AML mutex
 110  *
 111  ******************************************************************************/
 112
 113 ACPI_STATUS
 114 acpi_aml_acquire_mutex (
 115         ACPI_OPERAND_OBJECT     *time_desc,
 116         ACPI_OPERAND_OBJECT     *obj_desc,
 117         ACPI_WALK_STATE         *walk_state)
 118 {
 119         ACPI_STATUS             status;
 120
 121
 122         if (!obj_desc) {
 123                 return (AE_BAD_PARAMETER);
 124         }
 125
 126         /*
 127          * Current Sync must be less than or equal to the sync level of the
 128          * mutex.  This mechanism provides some deadlock prevention
 129          */
 130         if (walk_state->current_sync_level > obj_desc->mutex.sync_level) {
 131                 return (AE_AML_MUTEX_ORDER);
 132         }
 133
 134         /*
 135          * If the mutex is already owned by this thread,
 136          * just increment the acquisition depth
 137          */
 138         if (obj_desc->mutex.owner == walk_state) {
 139                 obj_desc->mutex.acquisition_depth++;
 140                 return (AE_OK);
 141         }
 142
 143         /* Acquire the mutex, wait if necessary */
 144
 145         status = acpi_aml_system_acquire_mutex (time_desc, obj_desc);
 146         if (ACPI_FAILURE (status)) {
 147                 /* Includes failure from a timeout on Time_desc */
 148
 149                 return (status);
 150         }
 151
 152         /* Have the mutex, update mutex and walk info */
 153
 154         obj_desc->mutex.owner = walk_state;
 155         obj_desc->mutex.acquisition_depth = 1;
 156         walk_state->current_sync_level = obj_desc->mutex.sync_level;
 157
 158         /* Link the mutex to the walk state for force-unlock at method exit */
 159
 160         acpi_aml_link_mutex (obj_desc, (ACPI_OPERAND_OBJECT *)
 161                          &(walk_state->walk_list->acquired_mutex_list));
 162
 163         return (AE_OK);
 164 }
 165
 166
 167 /*******************************************************************************
 168  *
 169  * FUNCTION:    Acpi_aml_release_mutex
 170  *
 171  * PARAMETERS:  *Obj_desc           - The object descriptor for this op
 172  *
 173  * RETURN:      Status
 174  *
 175  * DESCRIPTION: Release a previously acquired Mutex.
 176  *
 177  ******************************************************************************/
 178
 179 ACPI_STATUS
 180 acpi_aml_release_mutex (
 181         ACPI_OPERAND_OBJECT     *obj_desc,
 182         ACPI_WALK_STATE         *walk_state)
 183 {
 184         ACPI_STATUS             status;
 185
 186
 187         if (!obj_desc) {
 188                 return (AE_BAD_PARAMETER);
 189         }
 190
 191         /*  The mutex must have been previously acquired in order to release it */
 192
 193         if (!obj_desc->mutex.owner) {
 194                 return (AE_AML_MUTEX_NOT_ACQUIRED);
 195         }
 196
 197         /* The Mutex is owned, but this thread must be the owner */
 198
 199         if (obj_desc->mutex.owner != walk_state) {
 200                 return (AE_AML_NOT_OWNER);
 201         }
 202
 203         /*
 204          * The sync level of the mutex must be less than or
 205          * equal to the current sync level
 206          */
 207         if (obj_desc->mutex.sync_level > walk_state->current_sync_level) {
 208                 return (AE_AML_MUTEX_ORDER);
 209         }
 210
 211         /*
 212          * Match multiple Acquires with multiple Releases
 213          */
 214         obj_desc->mutex.acquisition_depth--;
 215         if (obj_desc->mutex.acquisition_depth != 0) {
 216                 /* Just decrement the depth and return */
 217
 218                 return (AE_OK);
 219         }
 220
 221
 222         /* Release the mutex */
 223
 224         status = acpi_aml_system_release_mutex (obj_desc);
 225
 226         /* Update the mutex and walk state */
 227
 228         obj_desc->mutex.owner = NULL;
 229         walk_state->current_sync_level = obj_desc->mutex.sync_level;
 230
 231         /* Unlink the mutex from the owner's list */
 232
 233         acpi_aml_unlink_mutex (obj_desc);
 234
 235         return (AE_OK);
 236 }
 237
 238
 239 /*******************************************************************************
 240  *
 241  * FUNCTION:    Acpi_aml_release_all_mutexes
 242  *
 243  * PARAMETERS:  *Mutex_list           - Head of the mutex list
 244  *
 245  * RETURN:      Status
 246  *
 247  * DESCRIPTION: Release all mutexes in the list
 248  *
 249  ******************************************************************************/
 250
 251 ACPI_STATUS
 252 acpi_aml_release_all_mutexes (
 253         ACPI_OPERAND_OBJECT     *list_head)
 254 {
 255         ACPI_OPERAND_OBJECT     *next = list_head->mutex.next;
 256         ACPI_OPERAND_OBJECT     *this;
 257
 258
 259         /*
 260          * Traverse the list of owned mutexes, releasing each one.
 261          */
 262         while (next) {
 263                 this = next;
 264                 next = this->mutex.next;
 265
 266                 /* Mark mutex un-owned */
 267
 268                 this->mutex.owner = NULL;
 269                 this->mutex.prev = NULL;
 270                 this->mutex.next = NULL;
 271                 this->mutex.acquisition_depth = 0;
 272
 273                  /* Release the mutex */
 274
 275                 acpi_aml_system_release_mutex (this);
 276         }
 277
 278         return (AE_OK);
 279 }
 280
 281