linux/drivers/acpi/pci_root.c
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   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
  45ACPI_MODULE_NAME("pci_root");
  46#define ACPI_PCI_ROOT_CLASS             "pci_bridge"
  47#define ACPI_PCI_ROOT_DEVICE_NAME       "PCI Root Bridge"
  48static int acpi_pci_root_add(struct acpi_device *device,
  49                             const struct acpi_device_id *not_used);
  50static 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
  57static const struct acpi_device_id root_device_ids[] = {
  58        {"PNP0A03", 0},
  59        {"", 0},
  60};
  61
  62static 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/* Lock to protect both acpi_pci_roots and acpi_pci_drivers lists */
  69static DEFINE_MUTEX(acpi_pci_root_lock);
  70static LIST_HEAD(acpi_pci_roots);
  71static LIST_HEAD(acpi_pci_drivers);
  72
  73static DEFINE_MUTEX(osc_lock);
  74
  75int acpi_pci_register_driver(struct acpi_pci_driver *driver)
  76{
  77        int n = 0;
  78        struct acpi_pci_root *root;
  79
  80        mutex_lock(&acpi_pci_root_lock);
  81        list_add_tail(&driver->node, &acpi_pci_drivers);
  82        if (driver->add)
  83                list_for_each_entry(root, &acpi_pci_roots, node) {
  84                        driver->add(root);
  85                        n++;
  86                }
  87        mutex_unlock(&acpi_pci_root_lock);
  88
  89        return n;
  90}
  91EXPORT_SYMBOL(acpi_pci_register_driver);
  92
  93void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
  94{
  95        struct acpi_pci_root *root;
  96
  97        mutex_lock(&acpi_pci_root_lock);
  98        list_del(&driver->node);
  99        if (driver->remove)
 100                list_for_each_entry(root, &acpi_pci_roots, node)
 101                        driver->remove(root);
 102        mutex_unlock(&acpi_pci_root_lock);
 103}
 104EXPORT_SYMBOL(acpi_pci_unregister_driver);
 105
 106/**
 107 * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
 108 * @handle - the ACPI CA node in question.
 109 *
 110 * Note: we could make this API take a struct acpi_device * instead, but
 111 * for now, it's more convenient to operate on an acpi_handle.
 112 */
 113int acpi_is_root_bridge(acpi_handle handle)
 114{
 115        int ret;
 116        struct acpi_device *device;
 117
 118        ret = acpi_bus_get_device(handle, &device);
 119        if (ret)
 120                return 0;
 121
 122        ret = acpi_match_device_ids(device, root_device_ids);
 123        if (ret)
 124                return 0;
 125        else
 126                return 1;
 127}
 128EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
 129
 130static acpi_status
 131get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
 132{
 133        struct resource *res = data;
 134        struct acpi_resource_address64 address;
 135
 136        if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
 137            resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
 138            resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
 139                return AE_OK;
 140
 141        acpi_resource_to_address64(resource, &address);
 142        if ((address.address_length > 0) &&
 143            (address.resource_type == ACPI_BUS_NUMBER_RANGE)) {
 144                res->start = address.minimum;
 145                res->end = address.minimum + address.address_length - 1;
 146        }
 147
 148        return AE_OK;
 149}
 150
 151static acpi_status try_get_root_bridge_busnr(acpi_handle handle,
 152                                             struct resource *res)
 153{
 154        acpi_status status;
 155
 156        res->start = -1;
 157        status =
 158            acpi_walk_resources(handle, METHOD_NAME__CRS,
 159                                get_root_bridge_busnr_callback, res);
 160        if (ACPI_FAILURE(status))
 161                return status;
 162        if (res->start == -1)
 163                return AE_ERROR;
 164        return AE_OK;
 165}
 166
 167static u8 pci_osc_uuid_str[] = "33DB4D5B-1FF7-401C-9657-7441C03DD766";
 168
 169static acpi_status acpi_pci_run_osc(acpi_handle handle,
 170                                    const u32 *capbuf, u32 *retval)
 171{
 172        struct acpi_osc_context context = {
 173                .uuid_str = pci_osc_uuid_str,
 174                .rev = 1,
 175                .cap.length = 12,
 176                .cap.pointer = (void *)capbuf,
 177        };
 178        acpi_status status;
 179
 180        status = acpi_run_osc(handle, &context);
 181        if (ACPI_SUCCESS(status)) {
 182                *retval = *((u32 *)(context.ret.pointer + 8));
 183                kfree(context.ret.pointer);
 184        }
 185        return status;
 186}
 187
 188static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root,
 189                                        u32 support,
 190                                        u32 *control)
 191{
 192        acpi_status status;
 193        u32 result, capbuf[3];
 194
 195        support &= OSC_PCI_SUPPORT_MASKS;
 196        support |= root->osc_support_set;
 197
 198        capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
 199        capbuf[OSC_SUPPORT_TYPE] = support;
 200        if (control) {
 201                *control &= OSC_PCI_CONTROL_MASKS;
 202                capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
 203        } else {
 204                /* Run _OSC query only with existing controls. */
 205                capbuf[OSC_CONTROL_TYPE] = root->osc_control_set;
 206        }
 207
 208        status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
 209        if (ACPI_SUCCESS(status)) {
 210                root->osc_support_set = support;
 211                if (control)
 212                        *control = result;
 213        }
 214        return status;
 215}
 216
 217static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 218{
 219        acpi_status status;
 220        acpi_handle tmp;
 221
 222        status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
 223        if (ACPI_FAILURE(status))
 224                return status;
 225        mutex_lock(&osc_lock);
 226        status = acpi_pci_query_osc(root, flags, NULL);
 227        mutex_unlock(&osc_lock);
 228        return status;
 229}
 230
 231struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 232{
 233        struct acpi_pci_root *root;
 234        struct acpi_device *device;
 235
 236        if (acpi_bus_get_device(handle, &device) ||
 237            acpi_match_device_ids(device, root_device_ids))
 238                return NULL;
 239
 240        root = acpi_driver_data(device);
 241
 242        return root;
 243}
 244EXPORT_SYMBOL_GPL(acpi_pci_find_root);
 245
 246struct acpi_handle_node {
 247        struct list_head node;
 248        acpi_handle handle;
 249};
 250
 251/**
 252 * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 253 * @handle: the handle in question
 254 *
 255 * Given an ACPI CA handle, the desired PCI device is located in the
 256 * list of PCI devices.
 257 *
 258 * If the device is found, its reference count is increased and this
 259 * function returns a pointer to its data structure.  The caller must
 260 * decrement the reference count by calling pci_dev_put().
 261 * If no device is found, %NULL is returned.
 262 */
 263struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
 264{
 265        int dev, fn;
 266        unsigned long long adr;
 267        acpi_status status;
 268        acpi_handle phandle;
 269        struct pci_bus *pbus;
 270        struct pci_dev *pdev = NULL;
 271        struct acpi_handle_node *node, *tmp;
 272        struct acpi_pci_root *root;
 273        LIST_HEAD(device_list);
 274
 275        /*
 276         * Walk up the ACPI CA namespace until we reach a PCI root bridge.
 277         */
 278        phandle = handle;
 279        while (!acpi_is_root_bridge(phandle)) {
 280                node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
 281                if (!node)
 282                        goto out;
 283
 284                INIT_LIST_HEAD(&node->node);
 285                node->handle = phandle;
 286                list_add(&node->node, &device_list);
 287
 288                status = acpi_get_parent(phandle, &phandle);
 289                if (ACPI_FAILURE(status))
 290                        goto out;
 291        }
 292
 293        root = acpi_pci_find_root(phandle);
 294        if (!root)
 295                goto out;
 296
 297        pbus = root->bus;
 298
 299        /*
 300         * Now, walk back down the PCI device tree until we return to our
 301         * original handle. Assumes that everything between the PCI root
 302         * bridge and the device we're looking for must be a P2P bridge.
 303         */
 304        list_for_each_entry(node, &device_list, node) {
 305                acpi_handle hnd = node->handle;
 306                status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
 307                if (ACPI_FAILURE(status))
 308                        goto out;
 309                dev = (adr >> 16) & 0xffff;
 310                fn  = adr & 0xffff;
 311
 312                pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
 313                if (!pdev || hnd == handle)
 314                        break;
 315
 316                pbus = pdev->subordinate;
 317                pci_dev_put(pdev);
 318
 319                /*
 320                 * This function may be called for a non-PCI device that has a
 321                 * PCI parent (eg. a disk under a PCI SATA controller).  In that
 322                 * case pdev->subordinate will be NULL for the parent.
 323                 */
 324                if (!pbus) {
 325                        dev_dbg(&pdev->dev, "Not a PCI-to-PCI bridge\n");
 326                        pdev = NULL;
 327                        break;
 328                }
 329        }
 330out:
 331        list_for_each_entry_safe(node, tmp, &device_list, node)
 332                kfree(node);
 333
 334        return pdev;
 335}
 336EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 337
 338/**
 339 * acpi_pci_osc_control_set - Request control of PCI root _OSC features.
 340 * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
 341 * @mask: Mask of _OSC bits to request control of, place to store control mask.
 342 * @req: Mask of _OSC bits the control of is essential to the caller.
 343 *
 344 * Run _OSC query for @mask and if that is successful, compare the returned
 345 * mask of control bits with @req.  If all of the @req bits are set in the
 346 * returned mask, run _OSC request for it.
 347 *
 348 * The variable at the @mask address may be modified regardless of whether or
 349 * not the function returns success.  On success it will contain the mask of
 350 * _OSC bits the BIOS has granted control of, but its contents are meaningless
 351 * on failure.
 352 **/
 353acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 354{
 355        struct acpi_pci_root *root;
 356        acpi_status status;
 357        u32 ctrl, capbuf[3];
 358        acpi_handle tmp;
 359
 360        if (!mask)
 361                return AE_BAD_PARAMETER;
 362
 363        ctrl = *mask & OSC_PCI_CONTROL_MASKS;
 364        if ((ctrl & req) != req)
 365                return AE_TYPE;
 366
 367        root = acpi_pci_find_root(handle);
 368        if (!root)
 369                return AE_NOT_EXIST;
 370
 371        status = acpi_get_handle(handle, "_OSC", &tmp);
 372        if (ACPI_FAILURE(status))
 373                return status;
 374
 375        mutex_lock(&osc_lock);
 376
 377        *mask = ctrl | root->osc_control_set;
 378        /* No need to evaluate _OSC if the control was already granted. */
 379        if ((root->osc_control_set & ctrl) == ctrl)
 380                goto out;
 381
 382        /* Need to check the available controls bits before requesting them. */
 383        while (*mask) {
 384                status = acpi_pci_query_osc(root, root->osc_support_set, mask);
 385                if (ACPI_FAILURE(status))
 386                        goto out;
 387                if (ctrl == *mask)
 388                        break;
 389                ctrl = *mask;
 390        }
 391
 392        if ((ctrl & req) != req) {
 393                status = AE_SUPPORT;
 394                goto out;
 395        }
 396
 397        capbuf[OSC_QUERY_TYPE] = 0;
 398        capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
 399        capbuf[OSC_CONTROL_TYPE] = ctrl;
 400        status = acpi_pci_run_osc(handle, capbuf, mask);
 401        if (ACPI_SUCCESS(status))
 402                root->osc_control_set = *mask;
 403out:
 404        mutex_unlock(&osc_lock);
 405        return status;
 406}
 407EXPORT_SYMBOL(acpi_pci_osc_control_set);
 408
 409static int acpi_pci_root_add(struct acpi_device *device,
 410                             const struct acpi_device_id *not_used)
 411{
 412        unsigned long long segment, bus;
 413        acpi_status status;
 414        int result;
 415        struct acpi_pci_root *root;
 416        struct acpi_pci_driver *driver;
 417        u32 flags, base_flags;
 418
 419        root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 420        if (!root)
 421                return -ENOMEM;
 422
 423        segment = 0;
 424        status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
 425                                       &segment);
 426        if (ACPI_FAILURE(status) && status != AE_NOT_FOUND) {
 427                printk(KERN_ERR PREFIX "can't evaluate _SEG\n");
 428                result = -ENODEV;
 429                goto end;
 430        }
 431
 432        /* Check _CRS first, then _BBN.  If no _BBN, default to zero. */
 433        root->secondary.flags = IORESOURCE_BUS;
 434        status = try_get_root_bridge_busnr(device->handle, &root->secondary);
 435        if (ACPI_FAILURE(status)) {
 436                /*
 437                 * We need both the start and end of the downstream bus range
 438                 * to interpret _CBA (MMCONFIG base address), so it really is
 439                 * supposed to be in _CRS.  If we don't find it there, all we
 440                 * can do is assume [_BBN-0xFF] or [0-0xFF].
 441                 */
 442                root->secondary.end = 0xFF;
 443                printk(KERN_WARNING FW_BUG PREFIX
 444                       "no secondary bus range in _CRS\n");
 445                status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN,
 446                                               NULL, &bus);
 447                if (ACPI_SUCCESS(status))
 448                        root->secondary.start = bus;
 449                else if (status == AE_NOT_FOUND)
 450                        root->secondary.start = 0;
 451                else {
 452                        printk(KERN_ERR PREFIX "can't evaluate _BBN\n");
 453                        result = -ENODEV;
 454                        goto end;
 455                }
 456        }
 457
 458        INIT_LIST_HEAD(&root->node);
 459        root->device = device;
 460        root->segment = segment & 0xFFFF;
 461        strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 462        strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 463        device->driver_data = root;
 464
 465        printk(KERN_INFO PREFIX "%s [%s] (domain %04x %pR)\n",
 466               acpi_device_name(device), acpi_device_bid(device),
 467               root->segment, &root->secondary);
 468
 469        root->mcfg_addr = acpi_pci_root_get_mcfg_addr(device->handle);
 470
 471        /*
 472         * All supported architectures that use ACPI have support for
 473         * PCI domains, so we indicate this in _OSC support capabilities.
 474         */
 475        flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
 476        acpi_pci_osc_support(root, flags);
 477
 478        /*
 479         * TBD: Need PCI interface for enumeration/configuration of roots.
 480         */
 481
 482        mutex_lock(&acpi_pci_root_lock);
 483        list_add_tail(&root->node, &acpi_pci_roots);
 484        mutex_unlock(&acpi_pci_root_lock);
 485
 486        /*
 487         * Scan the Root Bridge
 488         * --------------------
 489         * Must do this prior to any attempt to bind the root device, as the
 490         * PCI namespace does not get created until this call is made (and
 491         * thus the root bridge's pci_dev does not exist).
 492         */
 493        root->bus = pci_acpi_scan_root(root);
 494        if (!root->bus) {
 495                printk(KERN_ERR PREFIX
 496                            "Bus %04x:%02x not present in PCI namespace\n",
 497                            root->segment, (unsigned int)root->secondary.start);
 498                result = -ENODEV;
 499                goto out_del_root;
 500        }
 501
 502        /* Indicate support for various _OSC capabilities. */
 503        if (pci_ext_cfg_avail())
 504                flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
 505        if (pcie_aspm_support_enabled()) {
 506                flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 507                OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 508        }
 509        if (pci_msi_enabled())
 510                flags |= OSC_MSI_SUPPORT;
 511        if (flags != base_flags) {
 512                status = acpi_pci_osc_support(root, flags);
 513                if (ACPI_FAILURE(status)) {
 514                        dev_info(&device->dev, "ACPI _OSC support "
 515                                "notification failed, disabling PCIe ASPM\n");
 516                        pcie_no_aspm();
 517                        flags = base_flags;
 518                }
 519        }
 520
 521        if (!pcie_ports_disabled
 522            && (flags & ACPI_PCIE_REQ_SUPPORT) == ACPI_PCIE_REQ_SUPPORT) {
 523                flags = OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL
 524                        | OSC_PCI_EXPRESS_NATIVE_HP_CONTROL
 525                        | OSC_PCI_EXPRESS_PME_CONTROL;
 526
 527                if (pci_aer_available()) {
 528                        if (aer_acpi_firmware_first())
 529                                dev_dbg(&device->dev,
 530                                        "PCIe errors handled by BIOS.\n");
 531                        else
 532                                flags |= OSC_PCI_EXPRESS_AER_CONTROL;
 533                }
 534
 535                dev_info(&device->dev,
 536                        "Requesting ACPI _OSC control (0x%02x)\n", flags);
 537
 538                status = acpi_pci_osc_control_set(device->handle, &flags,
 539                                       OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL);
 540                if (ACPI_SUCCESS(status)) {
 541                        dev_info(&device->dev,
 542                                "ACPI _OSC control (0x%02x) granted\n", flags);
 543                        if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
 544                                /*
 545                                 * We have ASPM control, but the FADT indicates
 546                                 * that it's unsupported. Clear it.
 547                                 */
 548                                pcie_clear_aspm(root->bus);
 549                        }
 550                } else {
 551                        dev_info(&device->dev,
 552                                "ACPI _OSC request failed (%s), "
 553                                "returned control mask: 0x%02x\n",
 554                                acpi_format_exception(status), flags);
 555                        pr_info("ACPI _OSC control for PCIe not granted, "
 556                                "disabling ASPM\n");
 557                        pcie_no_aspm();
 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        pci_acpi_add_bus_pm_notifier(device, root->bus);
 566        if (device->wakeup.flags.run_wake)
 567                device_set_run_wake(root->bus->bridge, true);
 568
 569        if (system_state != SYSTEM_BOOTING) {
 570                pcibios_resource_survey_bus(root->bus);
 571                pci_assign_unassigned_bus_resources(root->bus);
 572        }
 573
 574        mutex_lock(&acpi_pci_root_lock);
 575        list_for_each_entry(driver, &acpi_pci_drivers, node)
 576                if (driver->add)
 577                        driver->add(root);
 578        mutex_unlock(&acpi_pci_root_lock);
 579
 580        /* need to after hot-added ioapic is registered */
 581        if (system_state != SYSTEM_BOOTING)
 582                pci_enable_bridges(root->bus);
 583
 584        pci_bus_add_devices(root->bus);
 585        return 1;
 586
 587out_del_root:
 588        mutex_lock(&acpi_pci_root_lock);
 589        list_del(&root->node);
 590        mutex_unlock(&acpi_pci_root_lock);
 591
 592end:
 593        kfree(root);
 594        return result;
 595}
 596
 597static void acpi_pci_root_remove(struct acpi_device *device)
 598{
 599        struct acpi_pci_root *root = acpi_driver_data(device);
 600        struct acpi_pci_driver *driver;
 601
 602        pci_stop_root_bus(root->bus);
 603
 604        mutex_lock(&acpi_pci_root_lock);
 605        list_for_each_entry_reverse(driver, &acpi_pci_drivers, node)
 606                if (driver->remove)
 607                        driver->remove(root);
 608        mutex_unlock(&acpi_pci_root_lock);
 609
 610        device_set_run_wake(root->bus->bridge, false);
 611        pci_acpi_remove_bus_pm_notifier(device);
 612
 613        pci_remove_root_bus(root->bus);
 614
 615        mutex_lock(&acpi_pci_root_lock);
 616        list_del(&root->node);
 617        mutex_unlock(&acpi_pci_root_lock);
 618        kfree(root);
 619}
 620
 621void __init acpi_pci_root_init(void)
 622{
 623        acpi_hest_init();
 624
 625        if (!acpi_pci_disabled) {
 626                pci_acpi_crs_quirks();
 627                acpi_scan_add_handler(&pci_root_handler);
 628        }
 629}
 630/* Support root bridge hotplug */
 631
 632static void handle_root_bridge_insertion(acpi_handle handle)
 633{
 634        struct acpi_device *device;
 635
 636        if (!acpi_bus_get_device(handle, &device)) {
 637                printk(KERN_DEBUG "acpi device exists...\n");
 638                return;
 639        }
 640
 641        if (acpi_bus_scan(handle))
 642                printk(KERN_ERR "cannot add bridge to acpi list\n");
 643}
 644
 645static void handle_root_bridge_removal(struct acpi_device *device)
 646{
 647        acpi_status status;
 648        struct acpi_eject_event *ej_event;
 649
 650        ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
 651        if (!ej_event) {
 652                /* Inform firmware the hot-remove operation has error */
 653                (void) acpi_evaluate_hotplug_ost(device->handle,
 654                                        ACPI_NOTIFY_EJECT_REQUEST,
 655                                        ACPI_OST_SC_NON_SPECIFIC_FAILURE,
 656                                        NULL);
 657                return;
 658        }
 659
 660        ej_event->device = device;
 661        ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
 662
 663        status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device, ej_event);
 664        if (ACPI_FAILURE(status))
 665                kfree(ej_event);
 666}
 667
 668static void _handle_hotplug_event_root(struct work_struct *work)
 669{
 670        struct acpi_pci_root *root;
 671        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER };
 672        struct acpi_hp_work *hp_work;
 673        acpi_handle handle;
 674        u32 type;
 675
 676        hp_work = container_of(work, struct acpi_hp_work, work);
 677        handle = hp_work->handle;
 678        type = hp_work->type;
 679
 680        acpi_scan_lock_acquire();
 681
 682        root = acpi_pci_find_root(handle);
 683        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 684
 685        switch (type) {
 686        case ACPI_NOTIFY_BUS_CHECK:
 687                /* bus enumerate */
 688                printk(KERN_DEBUG "%s: Bus check notify on %s\n", __func__,
 689                                 (char *)buffer.pointer);
 690                if (!root)
 691                        handle_root_bridge_insertion(handle);
 692
 693                break;
 694
 695        case ACPI_NOTIFY_DEVICE_CHECK:
 696                /* device check */
 697                printk(KERN_DEBUG "%s: Device check notify on %s\n", __func__,
 698                                 (char *)buffer.pointer);
 699                if (!root)
 700                        handle_root_bridge_insertion(handle);
 701                break;
 702
 703        case ACPI_NOTIFY_EJECT_REQUEST:
 704                /* request device eject */
 705                printk(KERN_DEBUG "%s: Device eject notify on %s\n", __func__,
 706                                 (char *)buffer.pointer);
 707                if (root)
 708                        handle_root_bridge_removal(root->device);
 709                break;
 710        default:
 711                printk(KERN_WARNING "notify_handler: unknown event type 0x%x for %s\n",
 712                                 type, (char *)buffer.pointer);
 713                break;
 714        }
 715
 716        acpi_scan_lock_release();
 717        kfree(hp_work); /* allocated in handle_hotplug_event_bridge */
 718        kfree(buffer.pointer);
 719}
 720
 721static void handle_hotplug_event_root(acpi_handle handle, u32 type,
 722                                        void *context)
 723{
 724        alloc_acpi_hp_work(handle, type, context,
 725                                _handle_hotplug_event_root);
 726}
 727
 728static acpi_status __init
 729find_root_bridges(acpi_handle handle, u32 lvl, void *context, void **rv)
 730{
 731        acpi_status status;
 732        char objname[64];
 733        struct acpi_buffer buffer = { .length = sizeof(objname),
 734                                      .pointer = objname };
 735        int *count = (int *)context;
 736
 737        if (!acpi_is_root_bridge(handle))
 738                return AE_OK;
 739
 740        (*count)++;
 741
 742        acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
 743
 744        status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 745                                        handle_hotplug_event_root, NULL);
 746        if (ACPI_FAILURE(status))
 747                printk(KERN_DEBUG "acpi root: %s notify handler is not installed, exit status: %u\n",
 748                                  objname, (unsigned int)status);
 749        else
 750                printk(KERN_DEBUG "acpi root: %s notify handler is installed\n",
 751                                 objname);
 752
 753        return AE_OK;
 754}
 755
 756void __init acpi_pci_root_hp_init(void)
 757{
 758        int num = 0;
 759
 760        acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
 761                ACPI_UINT32_MAX, find_root_bridges, NULL, &num, NULL);
 762
 763        printk(KERN_DEBUG "Found %d acpi root devices\n", num);
 764}
 765
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