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                              const struct acpi_device_id *not_used);
  50 static void acpi_pci_root_remove(struct acpi_device *device);
  51
  52 #define ACPI_PCIE_REQ_SUPPORT (OSC_EXT_PCI_CONFIG_SUPPORT \
  53                                 | OSC_ACTIVE_STATE_PWR_SUPPORT \
  54                                 | OSC_CLOCK_PWR_CAPABILITY_SUPPORT \
  55                                 | OSC_MSI_SUPPORT)
  56
  57 static const struct acpi_device_id root_device_ids[] = {
  58         {"PNP0A03", 0},
  59         {"", 0},
  60 };
  61
  62 static struct acpi_scan_handler pci_root_handler = {
  63         .ids = root_device_ids,
  64         .attach = acpi_pci_root_add,
  65         .detach = acpi_pci_root_remove,
  66 };
  67
  68 static DEFINE_MUTEX(osc_lock);
  69
  70 /**
  71  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
  72  * @handle - the ACPI CA node in question.
  73  *
  74  * Note: we could make this API take a struct acpi_device * instead, but
  75  * for now, it's more convenient to operate on an acpi_handle.
  76  */
  77 int acpi_is_root_bridge(acpi_handle handle)
  78 {
  79         int ret;
  80         struct acpi_device *device;
  81
  82         ret = acpi_bus_get_device(handle, &device);
  83         if (ret)
  84                 return 0;
  85
  86         ret = acpi_match_device_ids(device, root_device_ids);
  87         if (ret)
  88                 return 0;
  89         else
  90                 return 1;
  91 }
  92 EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
  93
  94 static acpi_status
  95 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
  96 {
  97         struct resource *res = data;
  98         struct acpi_resource_address64 address;
  99         acpi_status status;
 100
 101         status = acpi_resource_to_address64(resource, &address);
 102         if (ACPI_FAILURE(status))
 103                 return AE_OK;
 104
 105         if ((address.address_length > 0) &&
 106             (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
 107                 res->start = address.minimum;
 108                 res->end = address.minimum + address.address_length - 1;
 109         }
 110
 111         return AE_OK;
 112 }
 113
 114 static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
 115                                              struct resource *res)
 116 {
 117         acpi_status status;
 118
 119         res->start = -1;
 120         status =
 121             acpi_walk_resources(handle, METHOD_NAME__CRS,
 122                                 get_root_bridge_busnr_callback, res);
 123         if (ACPI_FAILURE(status))
 124                 return status;
 125         if (res->start == -1)
 126                 return AE_ERROR;
 127         return AE_OK;
 128 }
 129
 130 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 131
 132 static acpi_status acpi_pci_run_osc(acpi_handle handle,
 133                                     const u32 *capbuf, u32 *retval)
 134 {
 135         struct acpi_osc_context context = {
 136                 .uuid_str = pci_osc_uuid_str,
 137                 .rev = 1,
 138                 .cap.length = 12,
 139                 .cap.pointer = (void *)capbuf,
 140         };
 141         acpi_status status;
 142
 143         status = acpi_run_osc(handle, &context);
 144         if (ACPI_SUCCESS(status)) {
 145                 *retval = *((u32 *)(context.ret.pointer + 8));
 146                 kfree(context.ret.pointer);
 147         }
 148         return status;
 149 }
 150
 151 static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 152                                         u32 support,
 153                                         u32 *control)
 154 {
 155         acpi_status status;
 156         u32 result, capbuf[3];
 157
 158         support &= OSC_PCI_SUPPORT_MASKS;
 159         support |= root->osc_support_set;
 160
 161         capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
 162         capbuf[OSC_SUPPORT_TYPE] = support;
 163         if (control) {
 164                 *control &= OSC_PCI_CONTROL_MASKS;
 165                 capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
 166         } else {
 167                 /* Run _OSC query only with existing controls. */
 168                 capbuf[OSC_CONTROL_TYPE] = root->osc_control_set;
 169         }
 170
 171         status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
 172         if (ACPI_SUCCESS(status)) {
 173                 root->osc_support_set = support;
 174                 if (control)
 175                         *control = result;
 176         }
 177         return status;
 178 }
 179
 180 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 181 {
 182         acpi_status status;
 183         acpi_handle tmp;
 184
 185         status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
 186         if (ACPI_FAILURE(status))
 187                 return status;
 188         mutex_lock(&osc_lock);
 189         status = acpi_pci_query_osc(root, flags, NULL);
 190         mutex_unlock(&osc_lock);
 191         return status;
 192 }
 193
 194 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 195 {
 196         struct acpi_pci_root *root;
 197         struct acpi_device *device;
 198
 199         if (acpi_bus_get_device(handle, &device) ||
 200             acpi_match_device_ids(device, root_device_ids))
 201                 return NULL;
 202
 203         root = acpi_driver_data(device);
 204
 205         return root;
 206 }
 207 EXPORT_SYMBOL_GPL(acpi_pci_find_root);
 208
 209 struct acpi_handle_node {
 210         struct list_head node;
 211         acpi_handle handle;
 212 };
 213
 214 /**
 215  * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 216  * @handle: the handle in question
 217  *
 218  * Given an ACPI CA handle, the desired PCI device is located in the
 219  * list of PCI devices.
 220  *
 221  * If the device is found, its reference count is increased and this
 222  * function returns a pointer to its data structure.  The caller must
 223  * decrement the reference count by calling pci_dev_put().
 224  * If no device is found, %NULL is returned.
 225  */
 226 struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
 227 {
 228         int dev, fn;
 229         unsigned long long adr;
 230         acpi_status status;
 231         acpi_handle phandle;
 232         struct pci_bus *pbus;
 233         struct pci_dev *pdev = NULL;
 234         struct acpi_handle_node *node, *tmp;
 235         struct acpi_pci_root *root;
 236         LIST_HEAD(device_list);
 237
 238         /*
 239          * Walk up the ACPI CA namespace until we reach a PCI root bridge.
 240          */
 241         phandle = handle;
 242         while (!acpi_is_root_bridge(phandle)) {
 243                 node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
 244                 if (!node)
 245                         goto out;
 246
 247                 INIT_LIST_HEAD(&node->node);
 248                 node->handle = phandle;
 249                 list_add(&node->node, &device_list);
 250
 251                 status = acpi_get_parent(phandle, &phandle);
 252                 if (ACPI_FAILURE(status))
 253                         goto out;
 254         }
 255
 256         root = acpi_pci_find_root(phandle);
 257         if (!root)
 258                 goto out;
 259
 260         pbus = root->bus;
 261
 262         /*
 263          * Now, walk back down the PCI device tree until we return to our
 264          * original handle. Assumes that everything between the PCI root
 265          * bridge and the device we're looking for must be a P2P bridge.
 266          */
 267         list_for_each_entry(node, &device_list, node) {
 268                 acpi_handle hnd = node->handle;
 269                 status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
 270                 if (ACPI_FAILURE(status))
 271                         goto out;
 272                 dev = (adr >> 16) & 0xffff;
 273                 fn  = adr & 0xffff;
 274
 275                 pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
 276                 if (!pdev || hnd == handle)
 277                         break;
 278
 279                 pbus = pdev->subordinate;
 280                 pci_dev_put(pdev);
 281
 282                 /*
 283                  * This function may be called for a non-PCI device that has a
 284                  * PCI parent (eg. a disk under a PCI SATA controller).  In that
 285                  * case pdev->subordinate will be NULL for the parent.
 286                  */
 287                 if (!pbus) {
 288                         dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
 289                         pdev = NULL;
 290                         break;
 291                 }
 292         }
 293 out:
 294         list_for_each_entry_safe(node, tmp, &device_list, node)
 295                 kfree(node);
 296
 297         return pdev;
 298 }
 299 EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 300
 301 /**
 302  * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
 303  * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
 304  * @mask: Mask of _OSC bits to request control of, place to store control mask.
 305  * @req: Mask of _OSC bits the control of is essential to the caller.
 306  *
 307  * Run _OSC query for @mask and if that is successful, compare the returned
 308  * mask of control bits with @req.  If all of the @req bits are set in the
 309  * returned mask, run _OSC request for it.
 310  *
 311  * The variable at the @mask address may be modified regardless of whether or
 312  * not the function returns success.  On success it will contain the mask of
 313  * _OSC bits the BIOS has granted control of, but its contents are meaningless
 314  * on failure.
 315  **/
 316 acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 317 {
 318         struct acpi_pci_root *root;
 319         acpi_status status;
 320         u32 ctrl, capbuf[3];
 321         acpi_handle tmp;
 322
 323         if (!mask)
 324                 return AE_BAD_PARAMETER;
 325
 326         ctrl = *mask & OSC_PCI_CONTROL_MASKS;
 327         if ((ctrl & req) != req)
 328                 return AE_TYPE;
 329
 330         root = acpi_pci_find_root(handle);
 331         if (!root)
 332                 return AE_NOT_EXIST;
 333
 334         status = acpi_get_handle(handle, "_OSC", &tmp);
 335         if (ACPI_FAILURE(status))
 336                 return status;
 337
 338         mutex_lock(&osc_lock);
 339
 340         *mask = ctrl | root->osc_control_set;
 341         /* No need to evaluate _OSC if the control was already granted. */
 342         if ((root->osc_control_set & ctrl) == ctrl)
 343                 goto out;
 344
 345         /* Need to check the available controls bits before requesting them. */
 346         while (*mask) {
 347                 status = acpi_pci_query_osc(root, root->osc_support_set, mask);
 348                 if (ACPI_FAILURE(status))
 349                         goto out;
 350                 if (ctrl == *mask)
 351                         break;
 352                 ctrl = *mask;
 353         }
 354
 355         if ((ctrl & req) != req) {
 356                 status = AE_SUPPORT;
 357                 goto out;
 358         }
 359
 360         capbuf[OSC_QUERY_TYPE] = 0;
 361         capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
 362         capbuf[OSC_CONTROL_TYPE] = ctrl;
 363         status = acpi_pci_run_osc(handle, capbuf, mask);
 364         if (ACPI_SUCCESS(status))
 365                 root->osc_control_set = *mask;
 366 out:
 367         mutex_unlock(&osc_lock);
 368         return status;
 369 }
 370 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 371
 372 static int acpi_pci_root_add(struct acpi_device *device,
 373                              const struct acpi_device_id *not_used)
 374 {
 375         unsigned long long segment, bus;
 376         acpi_status status;
 377         int result;
 378         struct acpi_pci_root *root;
 379         u32 flags, base_flags;
 380         acpi_handle handle = device->handle;
 381         bool no_aspm = false, clear_aspm = false;
 382
 383         root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 384         if (!root)
 385                 return -ENOMEM;
 386
 387         segment = 0;
 388         status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL,
 389                                        &segment);
 390         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 391                 dev_err(&device->dev,  "can't evaluate _SEG\n");
 392                 result = -ENODEV;
 393                 goto end;
 394         }
 395
 396         /* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
 397         root->secondary.flags = IORESOURCE_BUS;
 398         status = try_get_root_bridge_busnr(handle, &root->secondary);
 399         if (ACPI_FAILURE(status)) {
 400                 /*
 401                  * We need both the start and end of the downstream bus range
 402                  * to interpret _CBA (MMCONFIG base address), so it really is
 403                  * supposed to be in _CRS.  If we don't find it there, all we
 404                  * can do is assume [_BBN-0xFF] or [0-0xFF].
 405                  */
 406                 root->secondary.end = 0xFF;
 407                 dev_warn(&device->dev,
 408                          FW_BUG "no secondary bus range in _CRS\n");
 409                 status = acpi_evaluate_integer(handle, METHOD_NAME__BBN,
 410                                                NULL, &bus);
 411                 if (ACPI_SUCCESS(status))
 412                         root->secondary.start = bus;
 413                 else if (status == AE_NOT_FOUND)
 414                         root->secondary.start = 0;
 415                 else {
 416                         dev_err(&device->dev, "can't evaluate _BBN\n");
 417                         result = -ENODEV;
 418                         goto end;
 419                 }
 420         }
 421
 422         root->device = device;
 423         root->segment = segment & 0xFFFF;
 424         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 425         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 426         device->driver_data = root;
 427
 428         pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
 429                acpi_device_name(device), acpi_device_bid(device),
 430                root->segment, &root->secondary);
 431
 432         root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
 433
 434         /*
 435          * All supported architectures that use ACPI have support for
 436          * PCI domains, so we indicate this in _OSC support capabilities.
 437          */
 438         flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
 439         acpi_pci_osc_support(root, flags);
 440
 441         if (pci_ext_cfg_avail())
 442                 flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
 443         if (pcie_aspm_support_enabled()) {
 444                 flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 445                 OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 446         }
 447         if (pci_msi_enabled())
 448                 flags |= OSC_MSI_SUPPORT;
 449         if (flags != base_flags) {
 450                 status = acpi_pci_osc_support(root, flags);
 451                 if (ACPI_FAILURE(status)) {
 452                         dev_info(&device->dev, "ACPI _OSC support "
 453                                 "notification failed, disabling PCIe ASPM\n");
 454                         no_aspm = true;
 455                         flags = base_flags;
 456                 }
 457         }
 458
 459         if (!pcie_ports_disabled
 460             && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
 461                 flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
 462                         | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
 463                         | OSC_PCI_EXPRESS_PME_CONTROL;
 464
 465                 if (pci_aer_available()) {
 466                         if (aer_acpi_firmware_first())
 467                                 dev_dbg(&device->dev,
 468                                         "PCIe errors handled by BIOS.\n");
 469                         else
 470                                 flags |= OSC_PCI_EXPRESS_AER_CONTROL;
 471                 }
 472
 473                 dev_info(&device->dev,
 474                         "Requesting ACPI _OSC control (0x%02x)\n", flags);
 475
 476                 status = acpi_pci_osc_control_set(handle, &flags,
 477                                        OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
 478                 if (ACPI_SUCCESS(status)) {
 479                         dev_info(&device->dev,
 480                                 "ACPI _OSC control (0x%02x) granted\n", flags);
 481                         if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 482                                 /*
 483                                  * We have ASPM control, but the FADT indicates
 484                                  * that it's unsupported. Clear it.
 485                                  */
 486                                 clear_aspm = true;
 487                         }
 488                 } else {
 489                         dev_info(&device->dev,
 490                                 "ACPI _OSC request failed (%s), "
 491                                 "returned control mask: 0x%02x\n",
 492                                 acpi_format_exception(status), flags);
 493                         dev_info(&device->dev,
 494                                  "ACPI _OSC control for PCIe not granted, disabling ASPM\n");
 495                         /*
 496                          * We want to disable ASPM here, but aspm_disabled
 497                          * needs to remain in its state from boot so that we
 498                          * properly handle PCIe 1.1 devices.  So we set this
 499                          * flag here, to defer the action until after the ACPI
 500                          * root scan.
 501                          */
 502                         no_aspm = true;
 503                 }
 504         } else {
 505                 dev_info(&device->dev,
 506                          "Unable to request _OSC control "
 507                          "(_OSC support mask: 0x%02x)\n", flags);
 508         }
 509
 510         /*
 511          * TBD: Need PCI interface for enumeration/configuration of roots.
 512          */
 513
 514         /*
 515          * Scan the Root Bridge
 516          * --------------------
 517          * Must do this prior to any attempt to bind the root device, as the
 518          * PCI namespace does not get created until this call is made (and
 519          * thus the root bridge's pci_dev does not exist).
 520          */
 521         root->bus = pci_acpi_scan_root(root);
 522         if (!root->bus) {
 523                 dev_err(&device->dev,
 524                         "Bus %04x:%02x not present in PCI namespace\n",
 525                         root->segment, (unsigned int)root->secondary.start);
 526                 result = -ENODEV;
 527                 goto end;
 528         }
 529
 530         if (clear_aspm) {
 531                 dev_info(&device->dev, "Disabling ASPM (FADT indicates it is unsupported)\n");
 532                 pcie_clear_aspm(root->bus);
 533         }
 534         if (no_aspm)
 535                 pcie_no_aspm();
 536
 537         pci_acpi_add_bus_pm_notifier(device, root->bus);
 538         if (device->wakeup.flags.run_wake)
 539                 device_set_run_wake(root->bus->bridge, true);
 540
 541         if (system_state != SYSTEM_BOOTING) {
 542                 pcibios_resource_survey_bus(root->bus);
 543                 pci_assign_unassigned_root_bus_resources(root->bus);
 544         }
 545
 546         pci_bus_add_devices(root->bus);
 547         return 1;
 548
 549 end:
 550         kfree(root);
 551         return result;
 552 }
 553
 554 static void acpi_pci_root_remove(struct acpi_device *device)
 555 {
 556         struct acpi_pci_root *root = acpi_driver_data(device);
 557
 558         pci_stop_root_bus(root->bus);
 559
 560         device_set_run_wake(root->bus->bridge, false);
 561         pci_acpi_remove_bus_pm_notifier(device);
 562
 563         pci_remove_root_bus(root->bus);
 564
 565         kfree(root);
 566 }
 567
 568 void __init acpi_pci_root_init(void)
 569 {
 570         acpi_hest_init();
 571
 572         if (!acpi_pci_disabled) {
 573                 pci_acpi_crs_quirks();
 574                 acpi_scan_add_handler(&pci_root_handler);
 575         }
 576 }
 577 /* Support root bridge hotplug */
 578
 579 static void handle_root_bridge_insertion(acpi_handle handle)
 580 {
 581         struct acpi_device *device;
 582
 583         if (!acpi_bus_get_device(handle, &device)) {
 584                 dev_printk(KERN_DEBUG, &device->dev,
 585                            "acpi device already exists; ignoring notify\n");
 586                 return;
 587         }
 588
 589         if (acpi_bus_scan(handle))
 590                 acpi_handle_err(handle, "cannot add bridge to acpi list\n");
 591 }
 592
 593 static void handle_root_bridge_removal(struct acpi_device *device)
 594 {
 595         acpi_status status;
 596         struct acpi_eject_event *ej_event;
 597
 598         ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
 599         if (!ej_event) {
 600                 /* Inform firmware the hot-remove operation has error */
 601                 (void) acpi_evaluate_hotplug_ost(device->handle,
 602                                         ACPI_NOTIFY_EJECT_REQUEST,
 603                                         ACPI_OST_SC_NON_SPECIFIC_FAILURE,
 604                                         NULL);
 605                 return;
 606         }
 607
 608         ej_event->device = device;
 609         ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
 610
 611         status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
 612         if (ACPI_FAILURE(status))
 613                 kfree(ej_event);
 614 }
 615
 616 static void _handle_hotplug_event_root(struct work_struct *work)
 617 {
 618         struct acpi_pci_root *root;
 619         struct acpi_hp_work *hp_work;
 620         acpi_handle handle;
 621         u32 type;
 622
 623         hp_work = container_of(work, struct acpi_hp_work, work);
 624         handle = hp_work->handle;
 625         type = hp_work->type;
 626
 627         acpi_scan_lock_acquire();
 628
 629         root = acpi_pci_find_root(handle);
 630
 631         switch (type) {
 632         case ACPI_NOTIFY_BUS_CHECK:
 633                 /* bus enumerate */
 634                 acpi_handle_printk(KERN_DEBUG, handle,
 635                                    "Bus check notify on %s\n", __func__);
 636                 if (root)
 637                         acpiphp_check_host_bridge(handle);
 638                 else
 639                         handle_root_bridge_insertion(handle);
 640
 641                 break;
 642
 643         case ACPI_NOTIFY_DEVICE_CHECK:
 644                 /* device check */
 645                 acpi_handle_printk(KERN_DEBUG, handle,
 646                                    "Device check notify on %s\n", __func__);
 647                 if (!root)
 648                         handle_root_bridge_insertion(handle);
 649                 break;
 650
 651         case ACPI_NOTIFY_EJECT_REQUEST:
 652                 /* request device eject */
 653                 acpi_handle_printk(KERN_DEBUG, handle,
 654                                    "Device eject notify on %s\n", __func__);
 655                 if (root)
 656                         handle_root_bridge_removal(root->device);
 657                 break;
 658         default:
 659                 acpi_handle_warn(handle,
 660                                  "notify_handler: unknown event type 0x%x\n",
 661                                  type);
 662                 break;
 663         }
 664
 665         acpi_scan_lock_release();
 666         kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
 667 }
 668
 669 static void handle_hotplug_event_root(acpi_handle handle, u32 type,
 670                                         void *context)
 671 {
 672         alloc_acpi_hp_work(handle, type, context,
 673                                 _handle_hotplug_event_root);
 674 }
 675
 676 static acpi_status __init
 677 find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 678 {
 679         acpi_status status;
 680         int *count = (int *)context;
 681
 682         if (!acpi_is_root_bridge(handle))
 683                 return AE_OK;
 684
 685         (*count)++;
 686
 687         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 688                                         handle_hotplug_event_root, NULL);
 689         if (ACPI_FAILURE(status))
 690                 acpi_handle_printk(KERN_DEBUG, handle,
 691                         "notify handler is not installed, exit status: %u\n",
 692                          (unsigned int)status);
 693         else
 694                 acpi_handle_printk(KERN_DEBUG, handle,
 695                                    "notify handler is installed\n");
 696
 697         return AE_OK;
 698 }
 699
 700 void __init acpi_pci_root_hp_init(void)
 701 {
 702         int num = 0;
 703
 704         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 705                 ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
 706
 707         printk(KERN_DEBUG "Found %d acpi root devices\n", num);
 708 }