Pileus Git - ~andy/linux/blob - 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 #include "internal.h"
  43
  44 #define PREFIX "ACPI: "
  45
  46 #define _COMPONENT              ACPI_PCI_COMPONENT
  47 ACPI_MODULE_NAME("pci_root");
  48 #define ACPI_PCI_ROOT_CLASS             "pci_bridge"
  49 #define ACPI_PCI_ROOT_DEVICE_NAME       "PCI Root Bridge"
  50 static int acpi_pci_root_add(struct acpi_device *device,
  51                              const struct acpi_device_id *not_used);
  52 static void acpi_pci_root_remove(struct acpi_device *device);
  53
  54 #define ACPI_PCIE_REQ_SUPPORT (OSC_EXT_PCI_CONFIG_SUPPORT \
  55                                 | OSC_ACTIVE_STATE_PWR_SUPPORT \
  56                                 | OSC_CLOCK_PWR_CAPABILITY_SUPPORT \
  57                                 | OSC_MSI_SUPPORT)
  58
  59 static const struct acpi_device_id root_device_ids[] = {
  60         {"PNP0A03", 0},
  61         {"", 0},
  62 };
  63
  64 static struct acpi_scan_handler pci_root_handler = {
  65         .ids = root_device_ids,
  66         .attach = acpi_pci_root_add,
  67         .detach = acpi_pci_root_remove,
  68         .hotplug = {
  69                 .ignore = true,
  70         },
  71 };
  72
  73 static DEFINE_MUTEX(osc_lock);
  74
  75 /**
  76  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
  77  * @handle - the ACPI CA node in question.
  78  *
  79  * Note: we could make this API take a struct acpi_device * instead, but
  80  * for now, it's more convenient to operate on an acpi_handle.
  81  */
  82 int acpi_is_root_bridge(acpi_handle handle)
  83 {
  84         int ret;
  85         struct acpi_device *device;
  86
  87         ret = acpi_bus_get_device(handle, &device);
  88         if (ret)
  89                 return 0;
  90
  91         ret = acpi_match_device_ids(device, root_device_ids);
  92         if (ret)
  93                 return 0;
  94         else
  95                 return 1;
  96 }
  97 EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
  98
  99 static acpi_status
 100 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
 101 {
 102         struct resource *res = data;
 103         struct acpi_resource_address64 address;
 104         acpi_status status;
 105
 106         status = acpi_resource_to_address64(resource, &address);
 107         if (ACPI_FAILURE(status))
 108                 return AE_OK;
 109
 110         if ((address.address_length > 0) &&
 111             (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
 112                 res->start = address.minimum;
 113                 res->end = address.minimum + address.address_length - 1;
 114         }
 115
 116         return AE_OK;
 117 }
 118
 119 static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
 120                                              struct resource *res)
 121 {
 122         acpi_status status;
 123
 124         res->start = -1;
 125         status =
 126             acpi_walk_resources(handle, METHOD_NAME__CRS,
 127                                 get_root_bridge_busnr_callback, res);
 128         if (ACPI_FAILURE(status))
 129                 return status;
 130         if (res->start == -1)
 131                 return AE_ERROR;
 132         return AE_OK;
 133 }
 134
 135 static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 136
 137 static acpi_status acpi_pci_run_osc(acpi_handle handle,
 138                                     const u32 *capbuf, u32 *retval)
 139 {
 140         struct acpi_osc_context context = {
 141                 .uuid_str = pci_osc_uuid_str,
 142                 .rev = 1,
 143                 .cap.length = 12,
 144                 .cap.pointer = (void *)capbuf,
 145         };
 146         acpi_status status;
 147
 148         status = acpi_run_osc(handle, &context);
 149         if (ACPI_SUCCESS(status)) {
 150                 *retval = *((u32 *)(context.ret.pointer + 8));
 151                 kfree(context.ret.pointer);
 152         }
 153         return status;
 154 }
 155
 156 static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 157                                         u32 support,
 158                                         u32 *control)
 159 {
 160         acpi_status status;
 161         u32 result, capbuf[3];
 162
 163         support &= OSC_PCI_SUPPORT_MASKS;
 164         support |= root->osc_support_set;
 165
 166         capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
 167         capbuf[OSC_SUPPORT_TYPE] = support;
 168         if (control) {
 169                 *control &= OSC_PCI_CONTROL_MASKS;
 170                 capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
 171         } else {
 172                 /* Run _OSC query only with existing controls. */
 173                 capbuf[OSC_CONTROL_TYPE] = root->osc_control_set;
 174         }
 175
 176         status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
 177         if (ACPI_SUCCESS(status)) {
 178                 root->osc_support_set = support;
 179                 if (control)
 180                         *control = result;
 181         }
 182         return status;
 183 }
 184
 185 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 186 {
 187         acpi_status status;
 188         acpi_handle tmp;
 189
 190         status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
 191         if (ACPI_FAILURE(status))
 192                 return status;
 193         mutex_lock(&osc_lock);
 194         status = acpi_pci_query_osc(root, flags, NULL);
 195         mutex_unlock(&osc_lock);
 196         return status;
 197 }
 198
 199 struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 200 {
 201         struct acpi_pci_root *root;
 202         struct acpi_device *device;
 203
 204         if (acpi_bus_get_device(handle, &device) ||
 205             acpi_match_device_ids(device, root_device_ids))
 206                 return NULL;
 207
 208         root = acpi_driver_data(device);
 209
 210         return root;
 211 }
 212 EXPORT_SYMBOL_GPL(acpi_pci_find_root);
 213
 214 struct acpi_handle_node {
 215         struct list_head node;
 216         acpi_handle handle;
 217 };
 218
 219 /**
 220  * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 221  * @handle: the handle in question
 222  *
 223  * Given an ACPI CA handle, the desired PCI device is located in the
 224  * list of PCI devices.
 225  *
 226  * If the device is found, its reference count is increased and this
 227  * function returns a pointer to its data structure.  The caller must
 228  * decrement the reference count by calling pci_dev_put().
 229  * If no device is found, %NULL is returned.
 230  */
 231 struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
 232 {
 233         int dev, fn;
 234         unsigned long long adr;
 235         acpi_status status;
 236         acpi_handle phandle;
 237         struct pci_bus *pbus;
 238         struct pci_dev *pdev = NULL;
 239         struct acpi_handle_node *node, *tmp;
 240         struct acpi_pci_root *root;
 241         LIST_HEAD(device_list);
 242
 243         /*
 244          * Walk up the ACPI CA namespace until we reach a PCI root bridge.
 245          */
 246         phandle = handle;
 247         while (!acpi_is_root_bridge(phandle)) {
 248                 node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
 249                 if (!node)
 250                         goto out;
 251
 252                 INIT_LIST_HEAD(&node->node);
 253                 node->handle = phandle;
 254                 list_add(&node->node, &device_list);
 255
 256                 status = acpi_get_parent(phandle, &phandle);
 257                 if (ACPI_FAILURE(status))
 258                         goto out;
 259         }
 260
 261         root = acpi_pci_find_root(phandle);
 262         if (!root)
 263                 goto out;
 264
 265         pbus = root->bus;
 266
 267         /*
 268          * Now, walk back down the PCI device tree until we return to our
 269          * original handle. Assumes that everything between the PCI root
 270          * bridge and the device we're looking for must be a P2P bridge.
 271          */
 272         list_for_each_entry(node, &device_list, node) {
 273                 acpi_handle hnd = node->handle;
 274                 status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
 275                 if (ACPI_FAILURE(status))
 276                         goto out;
 277                 dev = (adr >> 16) & 0xffff;
 278                 fn  = adr & 0xffff;
 279
 280                 pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
 281                 if (!pdev || hnd == handle)
 282                         break;
 283
 284                 pbus = pdev->subordinate;
 285                 pci_dev_put(pdev);
 286
 287                 /*
 288                  * This function may be called for a non-PCI device that has a
 289                  * PCI parent (eg. a disk under a PCI SATA controller).  In that
 290                  * case pdev->subordinate will be NULL for the parent.
 291                  */
 292                 if (!pbus) {
 293                         dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
 294                         pdev = NULL;
 295                         break;
 296                 }
 297         }
 298 out:
 299         list_for_each_entry_safe(node, tmp, &device_list, node)
 300                 kfree(node);
 301
 302         return pdev;
 303 }
 304 EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 305
 306 /**
 307  * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
 308  * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
 309  * @mask: Mask of _OSC bits to request control of, place to store control mask.
 310  * @req: Mask of _OSC bits the control of is essential to the caller.
 311  *
 312  * Run _OSC query for @mask and if that is successful, compare the returned
 313  * mask of control bits with @req.  If all of the @req bits are set in the
 314  * returned mask, run _OSC request for it.
 315  *
 316  * The variable at the @mask address may be modified regardless of whether or
 317  * not the function returns success.  On success it will contain the mask of
 318  * _OSC bits the BIOS has granted control of, but its contents are meaningless
 319  * on failure.
 320  **/
 321 acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 322 {
 323         struct acpi_pci_root *root;
 324         acpi_status status;
 325         u32 ctrl, capbuf[3];
 326         acpi_handle tmp;
 327
 328         if (!mask)
 329                 return AE_BAD_PARAMETER;
 330
 331         ctrl = *mask & OSC_PCI_CONTROL_MASKS;
 332         if ((ctrl & req) != req)
 333                 return AE_TYPE;
 334
 335         root = acpi_pci_find_root(handle);
 336         if (!root)
 337                 return AE_NOT_EXIST;
 338
 339         status = acpi_get_handle(handle, "_OSC", &tmp);
 340         if (ACPI_FAILURE(status))
 341                 return status;
 342
 343         mutex_lock(&osc_lock);
 344
 345         *mask = ctrl | root->osc_control_set;
 346         /* No need to evaluate _OSC if the control was already granted. */
 347         if ((root->osc_control_set & ctrl) == ctrl)
 348                 goto out;
 349
 350         /* Need to check the available controls bits before requesting them. */
 351         while (*mask) {
 352                 status = acpi_pci_query_osc(root, root->osc_support_set, mask);
 353                 if (ACPI_FAILURE(status))
 354                         goto out;
 355                 if (ctrl == *mask)
 356                         break;
 357                 ctrl = *mask;
 358         }
 359
 360         if ((ctrl & req) != req) {
 361                 status = AE_SUPPORT;
 362                 goto out;
 363         }
 364
 365         capbuf[OSC_QUERY_TYPE] = 0;
 366         capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
 367         capbuf[OSC_CONTROL_TYPE] = ctrl;
 368         status = acpi_pci_run_osc(handle, capbuf, mask);
 369         if (ACPI_SUCCESS(status))
 370                 root->osc_control_set = *mask;
 371 out:
 372         mutex_unlock(&osc_lock);
 373         return status;
 374 }
 375 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 376
 377 static int acpi_pci_root_add(struct acpi_device *device,
 378                              const struct acpi_device_id *not_used)
 379 {
 380         unsigned long long segment, bus;
 381         acpi_status status;
 382         int result;
 383         struct acpi_pci_root *root;
 384         u32 flags, base_flags;
 385         acpi_handle handle = device->handle;
 386         bool no_aspm = false, clear_aspm = false;
 387
 388         root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 389         if (!root)
 390                 return -ENOMEM;
 391
 392         segment = 0;
 393         status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL,
 394                                        &segment);
 395         if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 396                 dev_err(&device->dev,  "can't evaluate _SEG\n");
 397                 result = -ENODEV;
 398                 goto end;
 399         }
 400
 401         /* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
 402         root->secondary.flags = IORESOURCE_BUS;
 403         status = try_get_root_bridge_busnr(handle, &root->secondary);
 404         if (ACPI_FAILURE(status)) {
 405                 /*
 406                  * We need both the start and end of the downstream bus range
 407                  * to interpret _CBA (MMCONFIG base address), so it really is
 408                  * supposed to be in _CRS.  If we don't find it there, all we
 409                  * can do is assume [_BBN-0xFF] or [0-0xFF].
 410                  */
 411                 root->secondary.end = 0xFF;
 412                 dev_warn(&device->dev,
 413                          FW_BUG "no secondary bus range in _CRS\n");
 414                 status = acpi_evaluate_integer(handle, METHOD_NAME__BBN,
 415                                                NULL, &bus);
 416                 if (ACPI_SUCCESS(status))
 417                         root->secondary.start = bus;
 418                 else if (status == AE_NOT_FOUND)
 419                         root->secondary.start = 0;
 420                 else {
 421                         dev_err(&device->dev, "can't evaluate _BBN\n");
 422                         result = -ENODEV;
 423                         goto end;
 424                 }
 425         }
 426
 427         root->device = device;
 428         root->segment = segment & 0xFFFF;
 429         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 430         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 431         device->driver_data = root;
 432
 433         pr_info(PREFIX "%s [%s] (domain %04x %pR)\n",
 434                acpi_device_name(device), acpi_device_bid(device),
 435                root->segment, &root->secondary);
 436
 437         root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
 438
 439         /*
 440          * All supported architectures that use ACPI have support for
 441          * PCI domains, so we indicate this in _OSC support capabilities.
 442          */
 443         flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
 444         acpi_pci_osc_support(root, flags);
 445
 446         if (pci_ext_cfg_avail())
 447                 flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
 448         if (pcie_aspm_support_enabled()) {
 449                 flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 450                 OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 451         }
 452         if (pci_msi_enabled())
 453                 flags |= OSC_MSI_SUPPORT;
 454         if (flags != base_flags) {
 455                 status = acpi_pci_osc_support(root, flags);
 456                 if (ACPI_FAILURE(status)) {
 457                         dev_info(&device->dev, "ACPI _OSC support "
 458                                 "notification failed, disabling PCIe ASPM\n");
 459                         no_aspm = true;
 460                         flags = base_flags;
 461                 }
 462         }
 463
 464         if (!pcie_ports_disabled
 465             && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
 466                 flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
 467                         | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
 468                         | OSC_PCI_EXPRESS_PME_CONTROL;
 469
 470                 if (pci_aer_available()) {
 471                         if (aer_acpi_firmware_first())
 472                                 dev_dbg(&device->dev,
 473                                         "PCIe errors handled by BIOS.\n");
 474                         else
 475                                 flags |= OSC_PCI_EXPRESS_AER_CONTROL;
 476                 }
 477
 478                 dev_info(&device->dev,
 479                         "Requesting ACPI _OSC control (0x%02x)\n", flags);
 480
 481                 status = acpi_pci_osc_control_set(handle, &flags,
 482                                        OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
 483                 if (ACPI_SUCCESS(status)) {
 484                         dev_info(&device->dev,
 485                                 "ACPI _OSC control (0x%02x) granted\n", flags);
 486                         if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 487                                 /*
 488                                  * We have ASPM control, but the FADT indicates
 489                                  * that it's unsupported. Clear it.
 490                                  */
 491                                 clear_aspm = true;
 492                         }
 493                 } else {
 494                         dev_info(&device->dev,
 495                                 "ACPI _OSC request failed (%s), "
 496                                 "returned control mask: 0x%02x\n",
 497                                 acpi_format_exception(status), flags);
 498                         dev_info(&device->dev,
 499                                  "ACPI _OSC control for PCIe not granted, disabling ASPM\n");
 500                         /*
 501                          * We want to disable ASPM here, but aspm_disabled
 502                          * needs to remain in its state from boot so that we
 503                          * properly handle PCIe 1.1 devices.  So we set this
 504                          * flag here, to defer the action until after the ACPI
 505                          * root scan.
 506                          */
 507                         no_aspm = true;
 508                 }
 509         } else {
 510                 dev_info(&device->dev,
 511                          "Unable to request _OSC control "
 512                          "(_OSC support mask: 0x%02x)\n", flags);
 513         }
 514
 515         /*
 516          * TBD: Need PCI interface for enumeration/configuration of roots.
 517          */
 518
 519         /*
 520          * Scan the Root Bridge
 521          * --------------------
 522          * Must do this prior to any attempt to bind the root device, as the
 523          * PCI namespace does not get created until this call is made (and
 524          * thus the root bridge's pci_dev does not exist).
 525          */
 526         root->bus = pci_acpi_scan_root(root);
 527         if (!root->bus) {
 528                 dev_err(&device->dev,
 529                         "Bus %04x:%02x not present in PCI namespace\n",
 530                         root->segment, (unsigned int)root->secondary.start);
 531                 device->driver_data = NULL;
 532                 result = -ENODEV;
 533                 goto end;
 534         }
 535
 536         if (clear_aspm) {
 537                 dev_info(&device->dev, "Disabling ASPM (FADT indicates it is unsupported)\n");
 538                 pcie_clear_aspm(root->bus);
 539         }
 540         if (no_aspm)
 541                 pcie_no_aspm();
 542
 543         pci_acpi_add_bus_pm_notifier(device, root->bus);
 544         if (device->wakeup.flags.run_wake)
 545                 device_set_run_wake(root->bus->bridge, true);
 546
 547         if (system_state != SYSTEM_BOOTING) {
 548                 pcibios_resource_survey_bus(root->bus);
 549                 pci_assign_unassigned_root_bus_resources(root->bus);
 550         }
 551
 552         pci_bus_add_devices(root->bus);
 553         return 1;
 554
 555 end:
 556         kfree(root);
 557         return result;
 558 }
 559
 560 static void acpi_pci_root_remove(struct acpi_device *device)
 561 {
 562         struct acpi_pci_root *root = acpi_driver_data(device);
 563
 564         pci_stop_root_bus(root->bus);
 565
 566         device_set_run_wake(root->bus->bridge, false);
 567         pci_acpi_remove_bus_pm_notifier(device);
 568
 569         pci_remove_root_bus(root->bus);
 570
 571         kfree(root);
 572 }
 573
 574 void __init acpi_pci_root_init(void)
 575 {
 576         acpi_hest_init();
 577
 578         if (!acpi_pci_disabled) {
 579                 pci_acpi_crs_quirks();
 580                 acpi_scan_add_handler(&pci_root_handler);
 581         }
 582 }
 583 /* Support root bridge hotplug */
 584
 585 static void handle_root_bridge_insertion(acpi_handle handle)
 586 {
 587         struct acpi_device *device;
 588
 589         if (!acpi_bus_get_device(handle, &device)) {
 590                 dev_printk(KERN_DEBUG, &device->dev,
 591                            "acpi device already exists; ignoring notify\n");
 592                 return;
 593         }
 594
 595         if (acpi_bus_scan(handle))
 596                 acpi_handle_err(handle, "cannot add bridge to acpi list\n");
 597 }
 598
 599 static void hotplug_event_root(void *data, u32 type)
 600 {
 601         acpi_handle handle = data;
 602         struct acpi_pci_root *root;
 603
 604         acpi_scan_lock_acquire();
 605
 606         root = acpi_pci_find_root(handle);
 607
 608         switch (type) {
 609         case ACPI_NOTIFY_BUS_CHECK:
 610                 /* bus enumerate */
 611                 acpi_handle_printk(KERN_DEBUG, handle,
 612                                    "Bus check notify on %s\n", __func__);
 613                 if (root)
 614                         acpiphp_check_host_bridge(handle);
 615                 else
 616                         handle_root_bridge_insertion(handle);
 617
 618                 break;
 619
 620         case ACPI_NOTIFY_DEVICE_CHECK:
 621                 /* device check */
 622                 acpi_handle_printk(KERN_DEBUG, handle,
 623                                    "Device check notify on %s\n", __func__);
 624                 if (!root)
 625                         handle_root_bridge_insertion(handle);
 626                 break;
 627
 628         case ACPI_NOTIFY_EJECT_REQUEST:
 629                 /* request device eject */
 630                 acpi_handle_printk(KERN_DEBUG, handle,
 631                                    "Device eject notify on %s\n", __func__);
 632                 if (!root)
 633                         break;
 634
 635                 get_device(&root->device->dev);
 636
 637                 acpi_scan_lock_release();
 638
 639                 acpi_bus_device_eject(root->device, ACPI_NOTIFY_EJECT_REQUEST);
 640                 return;
 641         default:
 642                 acpi_handle_warn(handle,
 643                                  "notify_handler: unknown event type 0x%x\n",
 644                                  type);
 645                 break;
 646         }
 647
 648         acpi_scan_lock_release();
 649 }
 650
 651 static void handle_hotplug_event_root(acpi_handle handle, u32 type,
 652                                         void *context)
 653 {
 654         acpi_hotplug_execute(hotplug_event_root, handle, type);
 655 }
 656
 657 static acpi_status __init
 658 find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 659 {
 660         acpi_status status;
 661         int *count = (int *)context;
 662
 663         if (!acpi_is_root_bridge(handle))
 664                 return AE_OK;
 665
 666         (*count)++;
 667
 668         status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 669                                         handle_hotplug_event_root, NULL);
 670         if (ACPI_FAILURE(status))
 671                 acpi_handle_printk(KERN_DEBUG, handle,
 672                         "notify handler is not installed, exit status: %u\n",
 673                          (unsigned int)status);
 674         else
 675                 acpi_handle_printk(KERN_DEBUG, handle,
 676                                    "notify handler is installed\n");
 677
 678         return AE_OK;
 679 }
 680
 681 void __init acpi_pci_root_hp_init(void)
 682 {
 683         int num = 0;
 684
 685         acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 686                 ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
 687
 688         printk(KERN_DEBUG "Found %d acpi root devices\n", num);
 689 }