drivers/acpi/system.c

   1 /*
   2  *  acpi_system.c - ACPI System Driver ($Revision: 63 $)
   3  *
   4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6  *
   7  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   8  *
   9  *  This program is free software; you can redistribute it and/or modify
  10  *  it under the terms of the GNU General Public License as published by
  11  *  the Free Software Foundation; either version 2 of the License, or (at
  12  *  your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful, but
  15  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  *  General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License along
  20  *  with this program; if not, write to the Free Software Foundation, Inc.,
  21  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  22  *
  23  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  24  */
  25
  26 #include <linux/proc_fs.h>
  27 #include <linux/seq_file.h>
  28 #include <linux/init.h>
  29 #include <linux/string.h>
  30 #include <asm/uaccess.h>
  31
  32 #include <acpi/acpi_drivers.h>
  33
  34 #define _COMPONENT              ACPI_SYSTEM_COMPONENT
  35 ACPI_MODULE_NAME("system");
  36 #ifdef MODULE_PARAM_PREFIX
  37 #undef MODULE_PARAM_PREFIX
  38 #endif
  39 #define MODULE_PARAM_PREFIX "acpi."
  40
  41 #define ACPI_SYSTEM_CLASS               "system"
  42 #define ACPI_SYSTEM_DEVICE_NAME         "System"
  43
  44 u32 acpi_irq_handled;
  45
  46 /*
  47  * Make ACPICA version work as module param
  48  */
  49 static int param_get_acpica_version(char *buffer, struct kernel_param *kp)
  50 {
  51         int result;
  52
  53         result = sprintf(buffer, "%x", ACPI_CA_VERSION);
  54
  55         return result;
  56 }
  57
  58 module_param_call(acpica_version, NULL, param_get_acpica_version, NULL, 0444);
  59
  60 /* --------------------------------------------------------------------------
  61                               FS Interface (/sys)
  62    -------------------------------------------------------------------------- */
  63 static LIST_HEAD(acpi_table_attr_list);
  64 static struct kobject *tables_kobj;
  65
  66 struct acpi_table_attr {
  67         struct bin_attribute attr;
  68         char name[8];
  69         int instance;
  70         struct list_head node;
  71 };
  72
  73 static ssize_t acpi_table_show(struct kobject *kobj,
  74                                struct bin_attribute *bin_attr, char *buf,
  75                                loff_t offset, size_t count)
  76 {
  77         struct acpi_table_attr *table_attr =
  78             container_of(bin_attr, struct acpi_table_attr, attr);
  79         struct acpi_table_header *table_header = NULL;
  80         acpi_status status;
  81         char name[ACPI_NAME_SIZE];
  82
  83         if (strncmp(table_attr->name, "NULL", 4))
  84                 memcpy(name, table_attr->name, ACPI_NAME_SIZE);
  85         else
  86                 memcpy(name, "\0\0\0\0", 4);
  87
  88         status =
  89             acpi_get_table(name, table_attr->instance,
  90                            &table_header);
  91         if (ACPI_FAILURE(status))
  92                 return -ENODEV;
  93
  94         return memory_read_from_buffer(buf, count, &offset,
  95                                         table_header, table_header->length);
  96 }
  97
  98 static void acpi_table_attr_init(struct acpi_table_attr *table_attr,
  99                                  struct acpi_table_header *table_header)
 100 {
 101         struct acpi_table_header *header = NULL;
 102         struct acpi_table_attr *attr = NULL;
 103
 104         if (table_header->signature[0] != '\0')
 105                 memcpy(table_attr->name, table_header->signature,
 106                         ACPI_NAME_SIZE);
 107         else
 108                 memcpy(table_attr->name, "NULL", 4);
 109
 110         list_for_each_entry(attr, &acpi_table_attr_list, node) {
 111                 if (!memcmp(table_attr->name, attr->name, ACPI_NAME_SIZE))
 112                         if (table_attr->instance < attr->instance)
 113                                 table_attr->instance = attr->instance;
 114         }
 115         table_attr->instance++;
 116
 117         if (table_attr->instance > 1 || (table_attr->instance == 1 &&
 118                                         !acpi_get_table
 119                                         (table_header->signature, 2, &header)))
 120                 sprintf(table_attr->name + ACPI_NAME_SIZE, "%d",
 121                         table_attr->instance);
 122
 123         table_attr->attr.size = 0;
 124         table_attr->attr.read = acpi_table_show;
 125         table_attr->attr.attr.name = table_attr->name;
 126         table_attr->attr.attr.mode = 0444;
 127
 128         return;
 129 }
 130
 131 static int acpi_system_sysfs_init(void)
 132 {
 133         struct acpi_table_attr *table_attr;
 134         struct acpi_table_header *table_header = NULL;
 135         int table_index = 0;
 136         int result;
 137
 138         tables_kobj = kobject_create_and_add("tables", acpi_kobj);
 139         if (!tables_kobj)
 140                 return -ENOMEM;
 141
 142         do {
 143                 result = acpi_get_table_by_index(table_index, &table_header);
 144                 if (!result) {
 145                         table_index++;
 146                         table_attr = NULL;
 147                         table_attr =
 148                             kzalloc(sizeof(struct acpi_table_attr), GFP_KERNEL);
 149                         if (!table_attr)
 150                                 return -ENOMEM;
 151
 152                         acpi_table_attr_init(table_attr, table_header);
 153                         result =
 154                             sysfs_create_bin_file(tables_kobj,
 155                                                   &table_attr->attr);
 156                         if (result) {
 157                                 kfree(table_attr);
 158                                 return result;
 159                         } else
 160                                 list_add_tail(&table_attr->node,
 161                                               &acpi_table_attr_list);
 162                 }
 163         } while (!result);
 164         kobject_uevent(tables_kobj, KOBJ_ADD);
 165
 166         return 0;
 167 }
 168
 169 /*
 170  * Detailed ACPI IRQ counters in /sys/firmware/acpi/interrupts/
 171  * See Documentation/ABI/testing/sysfs-firmware-acpi
 172  */
 173
 174 #define COUNT_GPE 0
 175 #define COUNT_SCI 1     /* acpi_irq_handled */
 176 #define COUNT_ERROR 2   /* other */
 177 #define NUM_COUNTERS_EXTRA 3
 178
 179 struct event_counter {
 180         u32 count;
 181         u32 flags;
 182 };
 183
 184 static struct event_counter *all_counters;
 185 static u32 num_gpes;
 186 static u32 num_counters;
 187 static struct attribute **all_attrs;
 188 static u32 acpi_gpe_count;
 189
 190 static struct attribute_group interrupt_stats_attr_group = {
 191         .name = "interrupts",
 192 };
 193 static struct kobj_attribute *counter_attrs;
 194
 195 static int count_num_gpes(void)
 196 {
 197         int count = 0;
 198         struct acpi_gpe_xrupt_info *gpe_xrupt_info;
 199         struct acpi_gpe_block_info *gpe_block;
 200         acpi_cpu_flags flags;
 201
 202         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 203
 204         gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
 205         while (gpe_xrupt_info) {
 206                 gpe_block = gpe_xrupt_info->gpe_block_list_head;
 207                 while (gpe_block) {
 208                         count += gpe_block->register_count *
 209                             ACPI_GPE_REGISTER_WIDTH;
 210                         gpe_block = gpe_block->next;
 211                 }
 212                 gpe_xrupt_info = gpe_xrupt_info->next;
 213         }
 214         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
 215
 216         return count;
 217 }
 218
 219 static int get_gpe_device(int index, acpi_handle *handle)
 220 {
 221         struct acpi_gpe_xrupt_info *gpe_xrupt_info;
 222         struct acpi_gpe_block_info *gpe_block;
 223         acpi_cpu_flags flags;
 224         struct acpi_namespace_node *node;
 225
 226         flags = acpi_os_acquire_lock(acpi_gbl_gpe_lock);
 227
 228         gpe_xrupt_info = acpi_gbl_gpe_xrupt_list_head;
 229         while (gpe_xrupt_info) {
 230                 gpe_block = gpe_xrupt_info->gpe_block_list_head;
 231                 node = gpe_block->node;
 232                 while (gpe_block) {
 233                         index -= gpe_block->register_count *
 234                             ACPI_GPE_REGISTER_WIDTH;
 235                         if (index < 0) {
 236                                 acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
 237                                 /* return NULL if it's FADT GPE */
 238                                 if (node->type != ACPI_TYPE_DEVICE)
 239                                         *handle = NULL;
 240                                 else
 241                                         *handle = node;
 242                                 return 0;
 243                         }
 244                         node = gpe_block->node;
 245                         gpe_block = gpe_block->next;
 246                 }
 247                 gpe_xrupt_info = gpe_xrupt_info->next;
 248         }
 249         acpi_os_release_lock(acpi_gbl_gpe_lock, flags);
 250
 251         return -ENODEV;
 252 }
 253
 254 static void delete_gpe_attr_array(void)
 255 {
 256         struct event_counter *tmp = all_counters;
 257
 258         all_counters = NULL;
 259         kfree(tmp);
 260
 261         if (counter_attrs) {
 262                 int i;
 263
 264                 for (i = 0; i < num_gpes; i++)
 265                         kfree(counter_attrs[i].attr.name);
 266
 267                 kfree(counter_attrs);
 268         }
 269         kfree(all_attrs);
 270
 271         return;
 272 }
 273
 274 void acpi_os_gpe_count(u32 gpe_number)
 275 {
 276         acpi_gpe_count++;
 277
 278         if (!all_counters)
 279                 return;
 280
 281         if (gpe_number < num_gpes)
 282                 all_counters[gpe_number].count++;
 283         else
 284                 all_counters[num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_ERROR].
 285                                         count++;
 286
 287         return;
 288 }
 289
 290 void acpi_os_fixed_event_count(u32 event_number)
 291 {
 292         if (!all_counters)
 293                 return;
 294
 295         if (event_number < ACPI_NUM_FIXED_EVENTS)
 296                 all_counters[num_gpes + event_number].count++;
 297         else
 298                 all_counters[num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_ERROR].
 299                                 count++;
 300
 301         return;
 302 }
 303
 304 static int get_status(u32 index, acpi_event_status *status, acpi_handle *handle)
 305 {
 306         int result = 0;
 307
 308         if (index >= num_gpes + ACPI_NUM_FIXED_EVENTS)
 309                 goto end;
 310
 311         if (index < num_gpes) {
 312                 result = get_gpe_device(index, handle);
 313                 if (result) {
 314                         ACPI_EXCEPTION((AE_INFO, AE_NOT_FOUND,
 315                                 "Invalid GPE 0x%x\n", index));
 316                         goto end;
 317                 }
 318                 result = acpi_get_gpe_status(*handle, index,
 319                                                 ACPI_NOT_ISR, status);
 320         } else if (index < (num_gpes + ACPI_NUM_FIXED_EVENTS))
 321                 result = acpi_get_event_status(index - num_gpes, status);
 322
 323 end:
 324         return result;
 325 }
 326
 327 static ssize_t counter_show(struct kobject *kobj,
 328         struct kobj_attribute *attr, char *buf)
 329 {
 330         int index = attr - counter_attrs;
 331         int size;
 332         acpi_handle handle;
 333         acpi_event_status status;
 334         int result = 0;
 335
 336         all_counters[num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_SCI].count =
 337                 acpi_irq_handled;
 338         all_counters[num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_GPE].count =
 339                 acpi_gpe_count;
 340
 341         size = sprintf(buf, "%8d", all_counters[index].count);
 342
 343         /* "gpe_all" or "sci" */
 344         if (index >= num_gpes + ACPI_NUM_FIXED_EVENTS)
 345                 goto end;
 346
 347         result = get_status(index, &status, &handle);
 348         if (result)
 349                 goto end;
 350
 351         if (!(status & ACPI_EVENT_FLAG_HANDLE))
 352                 size += sprintf(buf + size, "   invalid");
 353         else if (status & ACPI_EVENT_FLAG_ENABLED)
 354                 size += sprintf(buf + size, "   enabled");
 355         else if (status & ACPI_EVENT_FLAG_WAKE_ENABLED)
 356                 size += sprintf(buf + size, "   wake_enabled");
 357         else
 358                 size += sprintf(buf + size, "   disabled");
 359
 360 end:
 361         size += sprintf(buf + size, "\n");
 362         return result ? result : size;
 363 }
 364
 365 /*
 366  * counter_set() sets the specified counter.
 367  * setting the total "sci" file to any value clears all counters.
 368  * enable/disable/clear a gpe/fixed event in user space.
 369  */
 370 static ssize_t counter_set(struct kobject *kobj,
 371         struct kobj_attribute *attr, const char *buf, size_t size)
 372 {
 373         int index = attr - counter_attrs;
 374         acpi_event_status status;
 375         acpi_handle handle;
 376         int result = 0;
 377
 378         if (index == num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_SCI) {
 379                 int i;
 380                 for (i = 0; i < num_counters; ++i)
 381                         all_counters[i].count = 0;
 382                 acpi_gpe_count = 0;
 383                 acpi_irq_handled = 0;
 384                 goto end;
 385         }
 386
 387         /* show the event status for both GPEs and Fixed Events */
 388         result = get_status(index, &status, &handle);
 389         if (result)
 390                 goto end;
 391
 392         if (!(status & ACPI_EVENT_FLAG_HANDLE)) {
 393                 printk(KERN_WARNING PREFIX
 394                         "Can not change Invalid GPE/Fixed Event status\n");
 395                 return -EINVAL;
 396         }
 397
 398         if (index < num_gpes) {
 399                 if (!strcmp(buf, "disable\n") &&
 400                                 (status & ACPI_EVENT_FLAG_ENABLED))
 401                         result = acpi_disable_gpe(handle, index);
 402                 else if (!strcmp(buf, "enable\n") &&
 403                                 !(status & ACPI_EVENT_FLAG_ENABLED))
 404                         result = acpi_enable_gpe(handle, index);
 405                 else if (!strcmp(buf, "clear\n") &&
 406                                 (status & ACPI_EVENT_FLAG_SET))
 407                         result = acpi_clear_gpe(handle, index, ACPI_NOT_ISR);
 408                 else
 409                         all_counters[index].count = strtoul(buf, NULL, 0);
 410         } else if (index < num_gpes + ACPI_NUM_FIXED_EVENTS) {
 411                 int event = index - num_gpes;
 412                 if (!strcmp(buf, "disable\n") &&
 413                                 (status & ACPI_EVENT_FLAG_ENABLED))
 414                         result = acpi_disable_event(event, ACPI_NOT_ISR);
 415                 else if (!strcmp(buf, "enable\n") &&
 416                                 !(status & ACPI_EVENT_FLAG_ENABLED))
 417                         result = acpi_enable_event(event, ACPI_NOT_ISR);
 418                 else if (!strcmp(buf, "clear\n") &&
 419                                 (status & ACPI_EVENT_FLAG_SET))
 420                         result = acpi_clear_event(event);
 421                 else
 422                         all_counters[index].count = strtoul(buf, NULL, 0);
 423         } else
 424                 all_counters[index].count = strtoul(buf, NULL, 0);
 425
 426         if (ACPI_FAILURE(result))
 427                 result = -EINVAL;
 428 end:
 429         return result ? result : size;
 430 }
 431
 432 void acpi_irq_stats_init(void)
 433 {
 434         int i;
 435
 436         if (all_counters)
 437                 return;
 438
 439         num_gpes = count_num_gpes();
 440         num_counters = num_gpes + ACPI_NUM_FIXED_EVENTS + NUM_COUNTERS_EXTRA;
 441
 442         all_attrs = kzalloc(sizeof(struct attribute *) * (num_counters + 1),
 443                         GFP_KERNEL);
 444         if (all_attrs == NULL)
 445                 return;
 446
 447         all_counters = kzalloc(sizeof(struct event_counter) * (num_counters),
 448                                 GFP_KERNEL);
 449         if (all_counters == NULL)
 450                 goto fail;
 451
 452         counter_attrs = kzalloc(sizeof(struct kobj_attribute) * (num_counters),
 453                         GFP_KERNEL);
 454         if (counter_attrs == NULL)
 455                 goto fail;
 456
 457         for (i = 0; i < num_counters; ++i) {
 458                 char buffer[12];
 459                 char *name;
 460
 461                 if (i < num_gpes)
 462                         sprintf(buffer, "gpe%02X", i);
 463                 else if (i == num_gpes + ACPI_EVENT_PMTIMER)
 464                         sprintf(buffer, "ff_pmtimer");
 465                 else if (i == num_gpes + ACPI_EVENT_GLOBAL)
 466                         sprintf(buffer, "ff_gbl_lock");
 467                 else if (i == num_gpes + ACPI_EVENT_POWER_BUTTON)
 468                         sprintf(buffer, "ff_pwr_btn");
 469                 else if (i == num_gpes + ACPI_EVENT_SLEEP_BUTTON)
 470                         sprintf(buffer, "ff_slp_btn");
 471                 else if (i == num_gpes + ACPI_EVENT_RTC)
 472                         sprintf(buffer, "ff_rt_clk");
 473                 else if (i == num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_GPE)
 474                         sprintf(buffer, "gpe_all");
 475                 else if (i == num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_SCI)
 476                         sprintf(buffer, "sci");
 477                 else if (i == num_gpes + ACPI_NUM_FIXED_EVENTS + COUNT_ERROR)
 478                         sprintf(buffer, "error");
 479                 else
 480                         sprintf(buffer, "bug%02X", i);
 481
 482                 name = kzalloc(strlen(buffer) + 1, GFP_KERNEL);
 483                 if (name == NULL)
 484                         goto fail;
 485                 strncpy(name, buffer, strlen(buffer) + 1);
 486
 487                 counter_attrs[i].attr.name = name;
 488                 counter_attrs[i].attr.mode = 0644;
 489                 counter_attrs[i].show = counter_show;
 490                 counter_attrs[i].store = counter_set;
 491
 492                 all_attrs[i] = &counter_attrs[i].attr;
 493         }
 494
 495         interrupt_stats_attr_group.attrs = all_attrs;
 496         if (!sysfs_create_group(acpi_kobj, &interrupt_stats_attr_group))
 497                 return;
 498
 499 fail:
 500         delete_gpe_attr_array();
 501         return;
 502 }
 503
 504 static void __exit interrupt_stats_exit(void)
 505 {
 506         sysfs_remove_group(acpi_kobj, &interrupt_stats_attr_group);
 507
 508         delete_gpe_attr_array();
 509
 510         return;
 511 }
 512
 513 /* --------------------------------------------------------------------------
 514                               FS Interface (/proc)
 515    -------------------------------------------------------------------------- */
 516 #ifdef CONFIG_ACPI_PROCFS
 517 #define ACPI_SYSTEM_FILE_INFO           "info"
 518 #define ACPI_SYSTEM_FILE_EVENT          "event"
 519 #define ACPI_SYSTEM_FILE_DSDT           "dsdt"
 520 #define ACPI_SYSTEM_FILE_FADT           "fadt"
 521
 522 static int acpi_system_read_info(struct seq_file *seq, void *offset)
 523 {
 524
 525         seq_printf(seq, "version:                 %x\n", ACPI_CA_VERSION);
 526         return 0;
 527 }
 528
 529 static int acpi_system_info_open_fs(struct inode *inode, struct file *file)
 530 {
 531         return single_open(file, acpi_system_read_info, PDE(inode)->data);
 532 }
 533
 534 static const struct file_operations acpi_system_info_ops = {
 535         .owner = THIS_MODULE,
 536         .open = acpi_system_info_open_fs,
 537         .read = seq_read,
 538         .llseek = seq_lseek,
 539         .release = single_release,
 540 };
 541
 542 static ssize_t acpi_system_read_dsdt(struct file *, char __user *, size_t,
 543                                      loff_t *);
 544
 545 static const struct file_operations acpi_system_dsdt_ops = {
 546         .owner = THIS_MODULE,
 547         .read = acpi_system_read_dsdt,
 548 };
 549
 550 static ssize_t
 551 acpi_system_read_dsdt(struct file *file,
 552                       char __user * buffer, size_t count, loff_t * ppos)
 553 {
 554         acpi_status status = AE_OK;
 555         struct acpi_table_header *dsdt = NULL;
 556         ssize_t res;
 557
 558         status = acpi_get_table(ACPI_SIG_DSDT, 1, &dsdt);
 559         if (ACPI_FAILURE(status))
 560                 return -ENODEV;
 561
 562         res = simple_read_from_buffer(buffer, count, ppos, dsdt, dsdt->length);
 563
 564         return res;
 565 }
 566
 567 static ssize_t acpi_system_read_fadt(struct file *, char __user *, size_t,
 568                                      loff_t *);
 569
 570 static const struct file_operations acpi_system_fadt_ops = {
 571         .owner = THIS_MODULE,
 572         .read = acpi_system_read_fadt,
 573 };
 574
 575 static ssize_t
 576 acpi_system_read_fadt(struct file *file,
 577                       char __user * buffer, size_t count, loff_t * ppos)
 578 {
 579         acpi_status status = AE_OK;
 580         struct acpi_table_header *fadt = NULL;
 581         ssize_t res;
 582
 583         status = acpi_get_table(ACPI_SIG_FADT, 1, &fadt);
 584         if (ACPI_FAILURE(status))
 585                 return -ENODEV;
 586
 587         res = simple_read_from_buffer(buffer, count, ppos, fadt, fadt->length);
 588
 589         return res;
 590 }
 591
 592 static int acpi_system_procfs_init(void)
 593 {
 594         struct proc_dir_entry *entry;
 595         int error = 0;
 596
 597         /* 'info' [R] */
 598         entry = proc_create(ACPI_SYSTEM_FILE_INFO, S_IRUGO, acpi_root_dir,
 599                             &acpi_system_info_ops);
 600         if (!entry)
 601                 goto Error;
 602
 603         /* 'dsdt' [R] */
 604         entry = proc_create(ACPI_SYSTEM_FILE_DSDT, S_IRUSR, acpi_root_dir,
 605                             &acpi_system_dsdt_ops);
 606         if (!entry)
 607                 goto Error;
 608
 609         /* 'fadt' [R] */
 610         entry = proc_create(ACPI_SYSTEM_FILE_FADT, S_IRUSR, acpi_root_dir,
 611                             &acpi_system_fadt_ops);
 612         if (!entry)
 613                 goto Error;
 614
 615       Done:
 616         return error;
 617
 618       Error:
 619         remove_proc_entry(ACPI_SYSTEM_FILE_FADT, acpi_root_dir);
 620         remove_proc_entry(ACPI_SYSTEM_FILE_DSDT, acpi_root_dir);
 621         remove_proc_entry(ACPI_SYSTEM_FILE_INFO, acpi_root_dir);
 622
 623         error = -EFAULT;
 624         goto Done;
 625 }
 626 #else
 627 static int acpi_system_procfs_init(void)
 628 {
 629         return 0;
 630 }
 631 #endif
 632
 633 static int __init acpi_system_init(void)
 634 {
 635         int result = 0;
 636
 637         if (acpi_disabled)
 638                 return 0;
 639
 640         result = acpi_system_procfs_init();
 641         if (result)
 642                 return result;
 643
 644         result = acpi_system_sysfs_init();
 645
 646         return result;
 647 }
 648
 649 subsys_initcall(acpi_system_init);