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; 381 382 root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL); 383 if (!root) 384 return -ENOMEM; 385 386 segment = 0; 387 status = acpi_evaluate_integer(handle, METHOD_NAME__SEG, NULL, 388 &segment); 389 if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) { 390 dev_err(&device->dev, "can't evaluate _SEG\n"); 391 result = -ENODEV; 392 goto end; 393 } 394 395 /* Check _CRS first, then _BBN. If no _BBN, default to zero. */ 396 root->secondary.flags = IORESOURCE_BUS; 397 status = try_get_root_bridge_busnr(handle, &root->secondary); 398 if (ACPI_FAILURE(status)) { 399 /* 400 * We need both the start and end of the downstream bus range 401 * to interpret _CBA (MMCONFIG base address), so it really is 402 * supposed to be in _CRS. If we don't find it there, all we 403 * can do is assume [_BBN-0xFF] or [0-0xFF]. 404 */ 405 root->secondary.end = 0xFF; 406 dev_warn(&device->dev, 407 FW_BUG "no secondary bus range in _CRS\n"); 408 status = acpi_evaluate_integer(handle, METHOD_NAME__BBN, 409 NULL, &bus); 410 if (ACPI_SUCCESS(status)) 411 root->secondary.start = bus; 412 else if (status == AE_NOT_FOUND) 413 root->secondary.start = 0; 414 else { 415 dev_err(&device->dev, "can't evaluate _BBN\n"); 416 result = -ENODEV; 417 goto end; 418 } 419 } 420 421 root->device = device; 422 root->segment = segment & 0xFFFF; 423 strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME); 424 strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS); 425 device->driver_data = root; 426 427 pr_info(PREFIX "%s [%s] (domain %04x %pR)\n", 428 acpi_device_name(device), acpi_device_bid(device), 429 root->segment, &root->secondary); 430 431 root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle); 432 433 /* 434 * All supported architectures that use ACPI have support for 435 * PCI domains, so we indicate this in _OSC support capabilities. 436 */ 437 flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT; 438 acpi_pci_osc_support(root, flags); 439 440 /* 441 * TBD: Need PCI interface for enumeration/configuration of roots. 442 */ 443 444 /* 445 * Scan the Root Bridge 446 * -------------------- 447 * Must do this prior to any attempt to bind the root device, as the 448 * PCI namespace does not get created until this call is made (and 449 * thus the root bridge's pci_dev does not exist). 450 */ 451 root->bus = pci_acpi_scan_root(root); 452 if (!root->bus) { 453 dev_err(&device->dev, 454 "Bus %04x:%02x not present in PCI namespace\n", 455 root->segment, (unsigned int)root->secondary.start); 456 result = -ENODEV; 457 goto end; 458 } 459 460 /* Indicate support for various _OSC capabilities. */ 461 if (pci_ext_cfg_avail()) 462 flags |= OSC_EXT_PCI_CONFIG_SUPPORT; 463 if (pcie_aspm_support_enabled()) { 464 flags |= OSC_ACTIVE_STATE_PWR_SUPPORT | 465 OSC_CLOCK_PWR_CAPABILITY_SUPPORT; 466 } 467 if (pci_msi_enabled()) 468 flags |= OSC_MSI_SUPPORT; 469 if (flags != base_flags) { 470 status = acpi_pci_osc_support(root, flags); 471 if (ACPI_FAILURE(status)) { 472 dev_info(&device->dev, "ACPI _OSC support " 473 "notification failed, disabling PCIe ASPM\n"); 474 pcie_no_aspm(); 475 flags = base_flags; 476 } 477 } 478 479 if (!pcie_ports_disabled 480 && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) { 481 flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL 482 | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL 483 | OSC_PCI_EXPRESS_PME_CONTROL; 484 485 if (pci_aer_available()) { 486 if (aer_acpi_firmware_first()) 487 dev_dbg(&device->dev, 488 "PCIe errors handled by BIOS.\n"); 489 else 490 flags |= OSC_PCI_EXPRESS_AER_CONTROL; 491 } 492 493 dev_info(&device->dev, 494 "Requesting ACPI _OSC control (0x%02x)\n", flags); 495 496 status = acpi_pci_osc_control_set(handle, &flags, 497 OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL); 498 if (ACPI_SUCCESS(status)) { 499 dev_info(&device->dev, 500 "ACPI _OSC control (0x%02x) granted\n", flags); 501 if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) { 502 /* 503 * We have ASPM control, but the FADT indicates 504 * that it's unsupported. Clear it. 505 */ 506 pcie_clear_aspm(root->bus); 507 } 508 } else { 509 dev_info(&device->dev, 510 "ACPI _OSC request failed (%s), " 511 "returned control mask: 0x%02x\n", 512 acpi_format_exception(status), flags); 513 dev_info(&device->dev, 514 "ACPI _OSC control for PCIe not granted, disabling ASPM\n"); 515 pcie_no_aspm(); 516 } 517 } else { 518 dev_info(&device->dev, 519 "Unable to request _OSC control " 520 "(_OSC support mask: 0x%02x)\n", flags); 521 } 522 523 pci_acpi_add_bus_pm_notifier(device, root->bus); 524 if (device->wakeup.flags.run_wake) 525 device_set_run_wake(root->bus->bridge, true); 526 527 if (system_state != SYSTEM_BOOTING) { 528 pcibios_resource_survey_bus(root->bus); 529 pci_assign_unassigned_bus_resources(root->bus); 530 531 /* need to after hot-added ioapic is registered */ 532 pci_enable_bridges(root->bus); 533 } 534 535 pci_bus_add_devices(root->bus); 536 return 1; 537 538 end: 539 kfree(root); 540 return result; 541 } 542 543 static void acpi_pci_root_remove(struct acpi_device *device) 544 { 545 struct acpi_pci_root *root = acpi_driver_data(device); 546 547 pci_stop_root_bus(root->bus); 548 549 device_set_run_wake(root->bus->bridge, false); 550 pci_acpi_remove_bus_pm_notifier(device); 551 552 pci_remove_root_bus(root->bus); 553 554 kfree(root); 555 } 556 557 void __init acpi_pci_root_init(void) 558 { 559 acpi_hest_init(); 560 561 if (!acpi_pci_disabled) { 562 pci_acpi_crs_quirks(); 563 acpi_scan_add_handler(&pci_root_handler); 564 } 565 } 566 /* Support root bridge hotplug */ 567 568 static void handle_root_bridge_insertion(acpi_handle handle) 569 { 570 struct acpi_device *device; 571 572 if (!acpi_bus_get_device(handle, &device)) { 573 dev_printk(KERN_DEBUG, &device->dev, 574 "acpi device already exists; ignoring notify\n"); 575 return; 576 } 577 578 if (acpi_bus_scan(handle)) 579 acpi_handle_err(handle, "cannot add bridge to acpi list\n"); 580 } 581 582 static void handle_root_bridge_removal(struct acpi_device *device) 583 { 584 acpi_status status; 585 struct acpi_eject_event *ej_event; 586 587 ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL); 588 if (!ej_event) { 589 /* Inform firmware the hot-remove operation has error */ 590 (void) acpi_evaluate_hotplug_ost(device->handle, 591 ACPI_NOTIFY_EJECT_REQUEST, 592 ACPI_OST_SC_NON_SPECIFIC_FAILURE, 593 NULL); 594 return; 595 } 596 597 ej_event->device = device; 598 ej_event->event = ACPI_NOTIFY_EJECT_REQUEST; 599 600 status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event); 601 if (ACPI_FAILURE(status)) 602 kfree(ej_event); 603 } 604 605 static void _handle_hotplug_event_root(struct work_struct *work) 606 { 607 struct acpi_pci_root *root; 608 struct acpi_hp_work *hp_work; 609 acpi_handle handle; 610 u32 type; 611 612 hp_work = container_of(work, struct acpi_hp_work, work); 613 handle = hp_work->handle; 614 type = hp_work->type; 615 616 acpi_scan_lock_acquire(); 617 618 root = acpi_pci_find_root(handle); 619 620 switch (type) { 621 case ACPI_NOTIFY_BUS_CHECK: 622 /* bus enumerate */ 623 acpi_handle_printk(KERN_DEBUG, handle, 624 "Bus check notify on %s\n", __func__); 625 if (root) 626 acpiphp_check_host_bridge(handle); 627 else 628 handle_root_bridge_insertion(handle); 629 630 break; 631 632 case ACPI_NOTIFY_DEVICE_CHECK: 633 /* device check */ 634 acpi_handle_printk(KERN_DEBUG, handle, 635 "Device check notify on %s\n", __func__); 636 if (!root) 637 handle_root_bridge_insertion(handle); 638 break; 639 640 case ACPI_NOTIFY_EJECT_REQUEST: 641 /* request device eject */ 642 acpi_handle_printk(KERN_DEBUG, handle, 643 "Device eject notify on %s\n", __func__); 644 if (root) 645 handle_root_bridge_removal(root->device); 646 break; 647 default: 648 acpi_handle_warn(handle, 649 "notify_handler: unknown event type 0x%x\n", 650 type); 651 break; 652 } 653 654 acpi_scan_lock_release(); 655 kfree(hp_work); /* allocated in handle_hotplug_event_bridge */ 656 } 657 658 static void handle_hotplug_event_root(acpi_handle handle, u32 type, 659 void *context) 660 { 661 alloc_acpi_hp_work(handle, type, context, 662 _handle_hotplug_event_root); 663 } 664 665 static acpi_status __init 666 find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv) 667 { 668 acpi_status status; 669 int *count = (int *)context; 670 671 if (!acpi_is_root_bridge(handle)) 672 return AE_OK; 673 674 (*count)++; 675 676 status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY, 677 handle_hotplug_event_root, NULL); 678 if (ACPI_FAILURE(status)) 679 acpi_handle_printk(KERN_DEBUG, handle, 680 "notify handler is not installed, exit status: %u\n", 681 (unsigned int)status); 682 else 683 acpi_handle_printk(KERN_DEBUG, handle, 684 "notify handler is installed\n"); 685 686 return AE_OK; 687 } 688 689 void __init acpi_pci_root_hp_init(void) 690 { 691 int num = 0; 692 693 acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, 694 ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL); 695 696 printk(KERN_DEBUG "Found %d acpi root devices\n", num); 697 } 698