drivers/acpi/pci_root.c

   1 /*
   2  *  pci_root.c - ACPI PCI Root Bridge Driver ($Revision: 40 $)
   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/kernel.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <linux/types.h>
  30 #include <linux/mutex.h>
  31 #include <linux/pm.h>
  32 #include <linux/pm_runtime.h>
  33 #include <linux/pci.h>
  34 #include <linux/pci-acpi.h>
  35 #include <linux/pci-aspm.h>
  36 #include <linux/acpi.h>
  37 #include <linux/slab.h>
  38 #include <acpi/acpi_bus.h>
  39 #include <acpi/acpi_drivers.h>
  40 #include <acpi/apei.h>
  41
  42 #define PREFIX "ACPI: "
  43
  44 #define _COMPONENT              ACPI_PCI_COMPONENT
  45 ACPI_MODULE_NAME("pci_root");
  46 #define ACPI_PCI_ROOT_CLASS             "pci_bridge"
  47 #define ACPI_PCI_ROOT_DEVICE_NAME       "PCI Root Bridge"
  48 static int acpi_pci_root_add(struct acpi_device *device);
  49 static int acpi_pci_root_remove(struct acpi_device *device, int type);
  50
  51 #define ACPI_PCIE_REQ_SUPPORT (OSC_EXT_PCI_CONFIG_SUPPORT \
  52                                 | OSC_ACTIVE_STATE_PWR_SUPPORT \
  53                                 | OSC_CLOCK_PWR_CAPABILITY_SUPPORT \
  54                                 | OSC_MSI_SUPPORT)
  55
  56 static const struct acpi_device_id root_device_ids[] = {
  57         {"PNP0A03", 0},
  58         {"", 0},
  59 };
  60 MODULE_DEVICE_TABLE(acpi, root_device_ids);
  61
  62 static struct acpi_driver acpi_pci_root_driver = {
  63         .name = "pci_root",
  64         .class = ACPI_PCI_ROOT_CLASS,
  65         .ids = root_device_ids,
  66         .ops = {
  67                 .add = acpi_pci_root_add,
  68                 .remove = acpi_pci_root_remove,
  69                 },
  70 };
  71
  72 /* Lock to protect both acpi_pci_roots and acpi_pci_drivers lists */
  73 static DEFINE_MUTEX(acpi_pci_root_lock);
  74 static LIST_HEAD(acpi_pci_roots);
  75 static LIST_HEAD(acpi_pci_drivers);
  76
  77 static DEFINE_MUTEX(osc_lock);
  78
  79 int acpi_pci_register_driver(struct acpi_pci_driver *driver)
  80 {
  81         int n = 0;
  82         struct acpi_pci_root *root;
  83
  84         mutex_lock(&acpi_pci_root_lock);
  85         list_add_tail(&driver->node, &acpi_pci_drivers);
  86         if (driver->add)
  87                 list_for_each_entry(root, &acpi_pci_roots, node) {
  88                         driver->add(root);
  89                         n++;
  90                 }
  91         mutex_unlock(&acpi_pci_root_lock);
  92
  93         return n;
  94 }
  95 EXPORT_SYMBOL(acpi_pci_register_driver);
  96
  97 void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
  98 {
  99         struct acpi_pci_root *root;
 100
 101         mutex_lock(&acpi_pci_root_lock);
 102         list_del(&driver->node);
 103         if (driver->remove)
 104                 list_for_each_entry(root, &acpi_pci_roots, node)
 105                         driver->remove(root);
 106         mutex_unlock(&acpi_pci_root_lock);
 107 }
 108 EXPORT_SYMBOL(acpi_pci_unregister_driver);
 109
 110 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
 111 {
 112         struct acpi_pci_root *root;
 113         acpi_handle handle = NULL;
 114
 115         mutex_lock(&acpi_pci_root_lock);
 116         list_for_each_entry(root, &acpi_pci_roots, node)
 117                 if ((root->segment == (u16) seg) &&
 118                     (root->secondary.start == (u16) bus)) {
 119                         handle = root->device->handle;
 120                         break;
 121                 }
 122         mutex_unlock(&acpi_pci_root_lock);
 123         return handle;
 124 }
 125
 126 EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
 127
 128 /**
 129  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
 130  * @handle - the ACPI CA node in question.
 131  *
 132  * Note: we could make this API take a struct acpi_device * instead, but
 133  * for now, it's more convenient to operate on an acpi_handle.
 134  */
 135 int acpi_is_root_bridge(acpi_handle handle)
 136 {
 137         int ret;
 138         struct acpi_device *device;
 139
 140         ret = acpi_bus_get_device(handle, &device);
 141         if (ret)
 142                 return 0;
 143
 144         ret = acpi_match_device_ids(device, root_device_ids);
 145         if (ret)
 146                 return 0;
 147         else
 148                 return 1;
 149 }
 150 EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
 151
 152 static acpi_status
 153 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
 154 {
 155         struct resource *res = data;
 156         struct acpi_resource_address64 address;
 157
 158         if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
 159             resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
 160             resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
 161                 return AE_OK;
 162
 163         acpi_resource_to_address64(resource, &address);
 164         if ((address.address_length > 0) &&
 165             (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
 166                 res->start = address.minimum;
 167                 res->end = address.minimum + address.address_length - 1;
 168         }
 169
 170         return AE_OK;
 171 }
 172
 173 static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
 174                                              struct resource *res)
 175 {
 176         acpi_status status;
 177
 178         res->start = -1;
 179         status =
 180             acpi_walk_resources(handle, METHOD_NAME__CRS,
 181                                 get_root_bridge_busnr_callback, res);
 182         if (ACPI_FAILURE(status))
 183                 return status;
 184         if (res->start == -1)
 185                 return AE_ERROR;
 186         return AE_OK;
 187 }
 188
 189 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 190
 191 static acpi_status acpi_pci_run_osc(acpi_handle handle,
 192                                     const u32 *capbuf, u32 *retval)
 193 {
 194         struct acpi_osc_context context = {
 195                 .uuid_str = pci_osc_uuid_str,
 196                 .rev = 1,
 197                 .cap.length = 12,
 198                 .cap.pointer = (void *)capbuf,
 199         };
 200         acpi_status status;
 201
 202         status = acpi_run_osc(handle, &context);
 203         if (ACPI_SUCCESS(status)) {
 204                 *retval = *((u32 *)(context.ret.pointer + 8));
 205                 kfree(context.ret.pointer);
 206         }
 207         return status;
 208 }
 209
 210 static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 211                                         u32 support,
 212                                         u32 *control)
 213 {
 214         acpi_status status;
 215         u32 result, capbuf[3];
 216
 217         support &= OSC_PCI_SUPPORT_MASKS;
 218         support |= root->osc_support_set;
 219
 220         capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
 221         capbuf[OSC_SUPPORT_TYPE] = support;
 222         if (control) {
 223                 *control &= OSC_PCI_CONTROL_MASKS;
 224                 capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
 225         } else {
 226                 /* Run _OSC query for all possible controls. */
 227                 capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
 228         }
 229
 230         status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
 231         if (ACPI_SUCCESS(status)) {
 232                 root->osc_support_set = support;
 233                 if (control)
 234                         *control = result;
 235         }
 236         return status;
 237 }
 238
 239 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 240 {
 241         acpi_status status;
 242         acpi_handle tmp;
 243
 244         status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
 245         if (ACPI_FAILURE(status))
 246                 return status;
 247         mutex_lock(&osc_lock);
 248         status = acpi_pci_query_osc(root, flags, NULL);
 249         mutex_unlock(&osc_lock);
 250         return status;
 251 }
 252
 253 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 254 {
 255         struct acpi_pci_root *root;
 256         struct acpi_device *device;
 257
 258         if (acpi_bus_get_device(handle, &device) ||
 259             acpi_match_device_ids(device, root_device_ids))
 260                 return NULL;
 261
 262         root = acpi_driver_data(device);
 263
 264         return root;
 265 }
 266 EXPORT_SYMBOL_GPL(acpi_pci_find_root);
 267
 268 struct acpi_handle_node {
 269         struct list_head node;
 270         acpi_handle handle;
 271 };
 272
 273 /**
 274  * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 275  * @handle: the handle in question
 276  *
 277  * Given an ACPI CA handle, the desired PCI device is located in the
 278  * list of PCI devices.
 279  *
 280  * If the device is found, its reference count is increased and this
 281  * function returns a pointer to its data structure.  The caller must
 282  * decrement the reference count by calling pci_dev_put().
 283  * If no device is found, %NULL is returned.
 284  */
 285 struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
 286 {
 287         int dev, fn;
 288         unsigned long long adr;
 289         acpi_status status;
 290         acpi_handle phandle;
 291         struct pci_bus *pbus;
 292         struct pci_dev *pdev = NULL;
 293         struct acpi_handle_node *node, *tmp;
 294         struct acpi_pci_root *root;
 295         LIST_HEAD(device_list);
 296
 297         /*
 298          * Walk up the ACPI CA namespace until we reach a PCI root bridge.
 299          */
 300         phandle = handle;
 301         while (!acpi_is_root_bridge(phandle)) {
 302                 node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
 303                 if (!node)
 304                         goto out;
 305
 306                 INIT_LIST_HEAD(&node->node);
 307                 node->handle = phandle;
 308                 list_add(&node->node, &device_list);
 309
 310                 status = acpi_get_parent(phandle, &phandle);
 311                 if (ACPI_FAILURE(status))
 312                         goto out;
 313         }
 314
 315         root = acpi_pci_find_root(phandle);
 316         if (!root)
 317                 goto out;
 318
 319         pbus = root->bus;
 320
 321         /*
 322          * Now, walk back down the PCI device tree until we return to our
 323          * original handle. Assumes that everything between the PCI root
 324          * bridge and the device we're looking for must be a P2P bridge.
 325          */
 326         list_for_each_entry(node, &device_list, node) {
 327                 acpi_handle hnd = node->handle;
 328                 status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
 329                 if (ACPI_FAILURE(status))
 330                         goto out;
 331                 dev = (adr >> 16) & 0xffff;
 332                 fn  = adr & 0xffff;
 333
 334                 pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
 335                 if (!pdev || hnd == handle)
 336                         break;
 337
 338                 pbus = pdev->subordinate;
 339                 pci_dev_put(pdev);
 340
 341                 /*
 342                  * This function may be called for a non-PCI device that has a
 343                  * PCI parent (eg. a disk under a PCI SATA controller).  In that
 344                  * case pdev->subordinate will be NULL for the parent.
 345                  */
 346                 if (!pbus) {
 347                         dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
 348                         pdev = NULL;
 349                         break;
 350                 }
 351         }
 352 out:
 353         list_for_each_entry_safe(node, tmp, &device_list, node)
 354                 kfree(node);
 355
 356         return pdev;
 357 }
 358 EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 359
 360 /**
 361  * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
 362  * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
 363  * @mask: Mask of _OSC bits to request control of, place to store control mask.
 364  * @req: Mask of _OSC bits the control of is essential to the caller.
 365  *
 366  * Run _OSC query for @mask and if that is successful, compare the returned
 367  * mask of control bits with @req.  If all of the @req bits are set in the
 368  * returned mask, run _OSC request for it.
 369  *
 370  * The variable at the @mask address may be modified regardless of whether or
 371  * not the function returns success.  On success it will contain the mask of
 372  * _OSC bits the BIOS has granted control of, but its contents are meaningless
 373  * on failure.
 374  **/
 375 acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 376 {
 377         struct acpi_pci_root *root;
 378         acpi_status status;
 379         u32 ctrl, capbuf[3];
 380         acpi_handle tmp;
 381
 382         if (!mask)
 383                 return AE_BAD_PARAMETER;
 384
 385         ctrl = *mask & OSC_PCI_CONTROL_MASKS;
 386         if ((ctrl & req) != req)
 387                 return AE_TYPE;
 388
 389         root = acpi_pci_find_root(handle);
 390         if (!root)
 391                 return AE_NOT_EXIST;
 392
 393         status = acpi_get_handle(handle, "_OSC", &tmp);
 394         if (ACPI_FAILURE(status))
 395                 return status;
 396
 397         mutex_lock(&osc_lock);
 398
 399         *mask = ctrl | root->osc_control_set;
 400         /* No need to evaluate _OSC if the control was already granted. */
 401         if ((root->osc_control_set & ctrl) == ctrl)
 402                 goto out;
 403
 404         /* Need to check the available controls bits before requesting them. */
 405         while (*mask) {
 406                 status = acpi_pci_query_osc(root, root->osc_support_set, mask);
 407                 if (ACPI_FAILURE(status))
 408                         goto out;
 409                 if (ctrl == *mask)
 410                         break;
 411                 ctrl = *mask;
 412         }
 413
 414         if ((ctrl & req) != req) {
 415                 status = AE_SUPPORT;
 416                 goto out;
 417         }
 418
 419         capbuf[OSC_QUERY_TYPE] = 0;
 420         capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
 421         capbuf[OSC_CONTROL_TYPE] = ctrl;
 422         status = acpi_pci_run_osc(handle, capbuf, mask);
 423         if (ACPI_SUCCESS(status))
 424                 root->osc_control_set = *mask;
 425 out:
 426         mutex_unlock(&osc_lock);
 427         return status;
 428 }
 429 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 430
 431 static int acpi_pci_root_add(struct acpi_device *device)
 432 {
 433         unsigned long long segment, bus;
 434         acpi_status status;
 435         int result;
 436         struct acpi_pci_root *root;
 437         acpi_handle handle;
 438         struct acpi_pci_driver *driver;
 439         u32 flags, base_flags;
 440         bool is_osc_granted = false;
 441
 442         root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 443         if (!root)
 444                 return -ENOMEM;
 445
 446         segment = 0;
 447         status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
 448                                        &segment);
 449         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 450                 printk(KERN_ERR PREFIX "can't evaluate _SEG\n");
 451                 result = -ENODEV;
 452                 goto end;
 453         }
 454
 455         /* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
 456         root->secondary.flags = IORESOURCE_BUS;
 457         status = try_get_root_bridge_busnr(device->handle, &root->secondary);
 458         if (ACPI_FAILURE(status)) {
 459                 /*
 460                  * We need both the start and end of the downstream bus range
 461                  * to interpret _CBA (MMCONFIG base address), so it really is
 462                  * supposed to be in _CRS.  If we don't find it there, all we
 463                  * can do is assume [_BBN-0xFF] or [0-0xFF].
 464                  */
 465                 root->secondary.end = 0xFF;
 466                 printk(KERN_WARNING FW_BUG PREFIX
 467                        "no secondary bus range in _CRS\n");
 468                 status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,
 469                                                NULL, &bus);
 470                 if (ACPI_SUCCESS(status))
 471                         root->secondary.start = bus;
 472                 else if (status == AE_NOT_FOUND)
 473                         root->secondary.start = 0;
 474                 else {
 475                         printk(KERN_ERR PREFIX "can't evaluate _BBN\n");
 476                         result = -ENODEV;
 477                         goto end;
 478                 }
 479         }
 480
 481         INIT_LIST_HEAD(&root->node);
 482         root->device = device;
 483         root->segment = segment & 0xFFFF;
 484         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 485         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 486         device->driver_data = root;
 487
 488         printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n",
 489                acpi_device_name(device), acpi_device_bid(device),
 490                root->segment, &root->secondary);
 491
 492         /*
 493          * PCI Routing Table
 494          * -----------------
 495          * Evaluate and parse _PRT, if exists.
 496          */
 497         status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
 498         if (ACPI_SUCCESS(status))
 499                 result = acpi_pci_irq_add_prt(device->handle, root->segment,
 500                                               root->secondary.start);
 501
 502         root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);
 503
 504         /*
 505          * All supported architectures that use ACPI have support for
 506          * PCI domains, so we indicate this in _OSC support capabilities.
 507          */
 508         flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
 509         acpi_pci_osc_support(root, flags);
 510
 511         /* Indicate support for various _OSC capabilities. */
 512         if (pci_ext_cfg_avail())
 513                 flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
 514         if (pcie_aspm_support_enabled()) {
 515                 flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 516                 OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 517         }
 518         if (pci_msi_enabled())
 519                 flags |= OSC_MSI_SUPPORT;
 520         if (flags != base_flags) {
 521                 status = acpi_pci_osc_support(root, flags);
 522                 if (ACPI_FAILURE(status)) {
 523                         dev_info(&device->dev, "ACPI _OSC support "
 524                                 "notification failed, disabling PCIe ASPM\n");
 525                         pcie_no_aspm();
 526                         flags = base_flags;
 527                 }
 528         }
 529         if (!pcie_ports_disabled
 530             && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
 531                 flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
 532                         | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
 533                         | OSC_PCI_EXPRESS_PME_CONTROL;
 534
 535                 if (pci_aer_available()) {
 536                         if (aer_acpi_firmware_first())
 537                                 dev_dbg(&device->dev,
 538                                         "PCIe errors handled by BIOS.\n");
 539                         else
 540                                 flags |= OSC_PCI_EXPRESS_AER_CONTROL;
 541                 }
 542
 543                 dev_info(&device->dev,
 544                         "Requesting ACPI _OSC control (0x%02x)\n", flags);
 545
 546                 status = acpi_pci_osc_control_set(device->handle, &flags,
 547                                        OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
 548                 if (ACPI_SUCCESS(status)) {
 549                         is_osc_granted = true;
 550                         dev_info(&device->dev,
 551                                 "ACPI _OSC control (0x%02x) granted\n", flags);
 552                 } else {
 553                         is_osc_granted = false;
 554                         dev_info(&device->dev,
 555                                 "ACPI _OSC request failed (%s), "
 556                                 "returned control mask: 0x%02x\n",
 557                                 acpi_format_exception(status), flags);
 558                 }
 559         } else {
 560                 dev_info(&device->dev,
 561                         "Unable to request _OSC control "
 562                         "(_OSC support mask: 0x%02x)\n", flags);
 563         }
 564
 565         /*
 566          * TBD: Need PCI interface for enumeration/configuration of roots.
 567          */
 568
 569         mutex_lock(&acpi_pci_root_lock);
 570         list_add_tail(&root->node, &acpi_pci_roots);
 571         mutex_unlock(&acpi_pci_root_lock);
 572
 573         /*
 574          * Scan the Root Bridge
 575          * --------------------
 576          * Must do this prior to any attempt to bind the root device, as the
 577          * PCI namespace does not get created until this call is made (and
 578          * thus the root bridge's pci_dev does not exist).
 579          */
 580         root->bus = pci_acpi_scan_root(root);
 581         if (!root->bus) {
 582                 printk(KERN_ERR PREFIX
 583                             "Bus %04x:%02x not present in PCI namespace\n",
 584                             root->segment, (unsigned int)root->secondary.start);
 585                 result = -ENODEV;
 586                 goto out_del_root;
 587         }
 588
 589         /* ASPM setting */
 590         if (is_osc_granted) {
 591                 if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM)
 592                         pcie_clear_aspm(root->bus);
 593         } else {
 594                 pr_info("ACPI _OSC control for PCIe not granted, "
 595                         "disabling ASPM\n");
 596                 pcie_no_aspm();
 597         }
 598
 599         pci_acpi_add_bus_pm_notifier(device, root->bus);
 600         if (device->wakeup.flags.run_wake)
 601                 device_set_run_wake(root->bus->bridge, true);
 602
 603         if (system_state != SYSTEM_BOOTING) {
 604                 pcibios_resource_survey_bus(root->bus);
 605                 pci_assign_unassigned_bus_resources(root->bus);
 606         }
 607
 608         mutex_lock(&acpi_pci_root_lock);
 609         list_for_each_entry(driver, &acpi_pci_drivers, node)
 610                 if (driver->add)
 611                         driver->add(root);
 612         mutex_unlock(&acpi_pci_root_lock);
 613
 614         /* need to after hot-added ioapic is registered */
 615         if (system_state != SYSTEM_BOOTING)
 616                 pci_enable_bridges(root->bus);
 617
 618         pci_bus_add_devices(root->bus);
 619         return 0;
 620
 621 out_del_root:
 622         mutex_lock(&acpi_pci_root_lock);
 623         list_del(&root->node);
 624         mutex_unlock(&acpi_pci_root_lock);
 625
 626         acpi_pci_irq_del_prt(root->segment, root->secondary.start);
 627 end:
 628         kfree(root);
 629         return result;
 630 }
 631
 632 static int acpi_pci_root_remove(struct acpi_device *device, int type)
 633 {
 634         acpi_status status;
 635         acpi_handle handle;
 636         struct acpi_pci_root *root = acpi_driver_data(device);
 637         struct acpi_pci_driver *driver;
 638
 639         pci_stop_root_bus(root->bus);
 640
 641         mutex_lock(&acpi_pci_root_lock);
 642         list_for_each_entry_reverse(driver, &acpi_pci_drivers, node)
 643                 if (driver->remove)
 644                         driver->remove(root);
 645         mutex_unlock(&acpi_pci_root_lock);
 646
 647         device_set_run_wake(root->bus->bridge, false);
 648         pci_acpi_remove_bus_pm_notifier(device);
 649
 650         status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
 651         if (ACPI_SUCCESS(status))
 652                 acpi_pci_irq_del_prt(root->segment, root->secondary.start);
 653
 654         pci_remove_root_bus(root->bus);
 655
 656         mutex_lock(&acpi_pci_root_lock);
 657         list_del(&root->node);
 658         mutex_unlock(&acpi_pci_root_lock);
 659         kfree(root);
 660         return 0;
 661 }
 662
 663 int __init acpi_pci_root_init(void)
 664 {
 665         acpi_hest_init();
 666
 667         if (acpi_pci_disabled)
 668                 return 0;
 669
 670         pci_acpi_crs_quirks();
 671         if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
 672                 return -ENODEV;
 673
 674         return 0;
 675 }