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/proc_fs.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/pm.h>
  33 #include <linux/pci.h>
  34 #include <linux/pci-acpi.h>
  35 #include <linux/acpi.h>
  36 #include <acpi/acpi_bus.h>
  37 #include <acpi/acpi_drivers.h>
  38
  39 #define _COMPONENT              ACPI_PCI_COMPONENT
  40 ACPI_MODULE_NAME("pci_root");
  41 #define ACPI_PCI_ROOT_CLASS             "pci_bridge"
  42 #define ACPI_PCI_ROOT_DEVICE_NAME       "PCI Root Bridge"
  43 static int acpi_pci_root_add(struct acpi_device *device);
  44 static int acpi_pci_root_remove(struct acpi_device *device, int type);
  45 static int acpi_pci_root_start(struct acpi_device *device);
  46
  47 static struct acpi_device_id root_device_ids[] = {
  48         {"PNP0A03", 0},
  49         {"", 0},
  50 };
  51 MODULE_DEVICE_TABLE(acpi, root_device_ids);
  52
  53 static struct acpi_driver acpi_pci_root_driver = {
  54         .name = "pci_root",
  55         .class = ACPI_PCI_ROOT_CLASS,
  56         .ids = root_device_ids,
  57         .ops = {
  58                 .add = acpi_pci_root_add,
  59                 .remove = acpi_pci_root_remove,
  60                 .start = acpi_pci_root_start,
  61                 },
  62 };
  63
  64 struct acpi_pci_root {
  65         struct list_head node;
  66         struct acpi_device * device;
  67         struct acpi_pci_id id;
  68         struct pci_bus *bus;
  69
  70         u32 osc_support_set;    /* _OSC state of support bits */
  71         u32 osc_control_set;    /* _OSC state of control bits */
  72         u32 osc_control_qry;    /* the latest _OSC query result */
  73
  74         u32 osc_queried:1;      /* has _OSC control been queried? */
  75 };
  76
  77 static LIST_HEAD(acpi_pci_roots);
  78
  79 static struct acpi_pci_driver *sub_driver;
  80 static DEFINE_MUTEX(osc_lock);
  81
  82 int acpi_pci_register_driver(struct acpi_pci_driver *driver)
  83 {
  84         int n = 0;
  85         struct list_head *entry;
  86
  87         struct acpi_pci_driver **pptr = &sub_driver;
  88         while (*pptr)
  89                 pptr = &(*pptr)->next;
  90         *pptr = driver;
  91
  92         if (!driver->add)
  93                 return 0;
  94
  95         list_for_each(entry, &acpi_pci_roots) {
  96                 struct acpi_pci_root *root;
  97                 root = list_entry(entry, struct acpi_pci_root, node);
  98                 driver->add(root->device->handle);
  99                 n++;
 100         }
 101
 102         return n;
 103 }
 104
 105 EXPORT_SYMBOL(acpi_pci_register_driver);
 106
 107 void acpi_pci_unregister_driver(struct acpi_pci_driver *driver)
 108 {
 109         struct list_head *entry;
 110
 111         struct acpi_pci_driver **pptr = &sub_driver;
 112         while (*pptr) {
 113                 if (*pptr == driver)
 114                         break;
 115                 pptr = &(*pptr)->next;
 116         }
 117         BUG_ON(!*pptr);
 118         *pptr = (*pptr)->next;
 119
 120         if (!driver->remove)
 121                 return;
 122
 123         list_for_each(entry, &acpi_pci_roots) {
 124                 struct acpi_pci_root *root;
 125                 root = list_entry(entry, struct acpi_pci_root, node);
 126                 driver->remove(root->device->handle);
 127         }
 128 }
 129
 130 EXPORT_SYMBOL(acpi_pci_unregister_driver);
 131
 132 acpi_handle acpi_get_pci_rootbridge_handle(unsigned int seg, unsigned int bus)
 133 {
 134         struct acpi_pci_root *tmp;
 135
 136         list_for_each_entry(tmp, &acpi_pci_roots, node) {
 137                 if ((tmp->id.segment == (u16) seg) && (tmp->id.bus == (u16) bus))
 138                         return tmp->device->handle;
 139         }
 140         return NULL;
 141 }
 142
 143 EXPORT_SYMBOL_GPL(acpi_get_pci_rootbridge_handle);
 144
 145 /**
 146  * acpi_is_root_bridge - determine whether an ACPI CA node is a PCI root bridge
 147  * @handle - the ACPI CA node in question.
 148  *
 149  * Note: we could make this API take a struct acpi_device * instead, but
 150  * for now, it's more convenient to operate on an acpi_handle.
 151  */
 152 int acpi_is_root_bridge(acpi_handle handle)
 153 {
 154         int ret;
 155         struct acpi_device *device;
 156
 157         ret = acpi_bus_get_device(handle, &device);
 158         if (ret)
 159                 return 0;
 160
 161         ret = acpi_match_device_ids(device, root_device_ids);
 162         if (ret)
 163                 return 0;
 164         else
 165                 return 1;
 166 }
 167 EXPORT_SYMBOL_GPL(acpi_is_root_bridge);
 168
 169 static acpi_status
 170 get_root_bridge_busnr_callback(struct acpi_resource *resource, void *data)
 171 {
 172         int *busnr = data;
 173         struct acpi_resource_address64 address;
 174
 175         if (resource->type != ACPI_RESOURCE_TYPE_ADDRESS16 &&
 176             resource->type != ACPI_RESOURCE_TYPE_ADDRESS32 &&
 177             resource->type != ACPI_RESOURCE_TYPE_ADDRESS64)
 178                 return AE_OK;
 179
 180         acpi_resource_to_address64(resource, &address);
 181         if ((address.address_length > 0) &&
 182             (address.resource_type == ACPI_BUS_NUMBER_RANGE))
 183                 *busnr = address.minimum;
 184
 185         return AE_OK;
 186 }
 187
 188 static acpi_status try_get_root_bridge_busnr(acpi_handle handle, int *busnum)
 189 {
 190         acpi_status status;
 191
 192         *busnum = -1;
 193         status =
 194             acpi_walk_resources(handle, METHOD_NAME__CRS,
 195                                 get_root_bridge_busnr_callback, busnum);
 196         if (ACPI_FAILURE(status))
 197                 return status;
 198         /* Check if we really get a bus number from _CRS */
 199         if (*busnum == -1)
 200                 return AE_ERROR;
 201         return AE_OK;
 202 }
 203
 204 static void acpi_pci_bridge_scan(struct acpi_device *device)
 205 {
 206         int status;
 207         struct acpi_device *child = NULL;
 208
 209         if (device->flags.bus_address)
 210                 if (device->parent && device->parent->ops.bind) {
 211                         status = device->parent->ops.bind(device);
 212                         if (!status) {
 213                                 list_for_each_entry(child, &device->children, node)
 214                                         acpi_pci_bridge_scan(child);
 215                         }
 216                 }
 217 }
 218
 219 static u8 OSC_UUID[16] = {0x5B, 0x4D, 0xDB, 0x33, 0xF7, 0x1F, 0x1C, 0x40,
 220                           0x96, 0x57, 0x74, 0x41, 0xC0, 0x3D, 0xD7, 0x66};
 221
 222 static acpi_status acpi_pci_run_osc(acpi_handle handle,
 223                                     const u32 *capbuf, u32 *retval)
 224 {
 225         acpi_status status;
 226         struct acpi_object_list input;
 227         union acpi_object in_params[4];
 228         struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
 229         union acpi_object *out_obj;
 230         u32 errors;
 231
 232         /* Setting up input parameters */
 233         input.count = 4;
 234         input.pointer = in_params;
 235         in_params[0].type               = ACPI_TYPE_BUFFER;
 236         in_params[0].buffer.length      = 16;
 237         in_params[0].buffer.pointer     = OSC_UUID;
 238         in_params[1].type               = ACPI_TYPE_INTEGER;
 239         in_params[1].integer.value      = 1;
 240         in_params[2].type               = ACPI_TYPE_INTEGER;
 241         in_params[2].integer.value      = 3;
 242         in_params[3].type               = ACPI_TYPE_BUFFER;
 243         in_params[3].buffer.length      = 12;
 244         in_params[3].buffer.pointer     = (u8 *)capbuf;
 245
 246         status = acpi_evaluate_object(handle, "_OSC", &input, &output);
 247         if (ACPI_FAILURE(status))
 248                 return status;
 249
 250         if (!output.length)
 251                 return AE_NULL_OBJECT;
 252
 253         out_obj = output.pointer;
 254         if (out_obj->type != ACPI_TYPE_BUFFER) {
 255                 printk(KERN_DEBUG "_OSC evaluation returned wrong type\n");
 256                 status = AE_TYPE;
 257                 goto out_kfree;
 258         }
 259         /* Need to ignore the bit0 in result code */
 260         errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
 261         if (errors) {
 262                 if (errors & OSC_REQUEST_ERROR)
 263                         printk(KERN_DEBUG "_OSC request failed\n");
 264                 if (errors & OSC_INVALID_UUID_ERROR)
 265                         printk(KERN_DEBUG "_OSC invalid UUID\n");
 266                 if (errors & OSC_INVALID_REVISION_ERROR)
 267                         printk(KERN_DEBUG "_OSC invalid revision\n");
 268                 if (errors & OSC_CAPABILITIES_MASK_ERROR) {
 269                         if (capbuf[OSC_QUERY_TYPE] & OSC_QUERY_ENABLE)
 270                                 goto out_success;
 271                         printk(KERN_DEBUG
 272                                "Firmware did not grant requested _OSC control\n");
 273                         status = AE_SUPPORT;
 274                         goto out_kfree;
 275                 }
 276                 status = AE_ERROR;
 277                 goto out_kfree;
 278         }
 279 out_success:
 280         *retval = *((u32 *)(out_obj->buffer.pointer + 8));
 281         status = AE_OK;
 282
 283 out_kfree:
 284         kfree(output.pointer);
 285         return status;
 286 }
 287
 288 static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, u32 flags)
 289 {
 290         acpi_status status;
 291         u32 support_set, result, capbuf[3];
 292
 293         /* do _OSC query for all possible controls */
 294         support_set = root->osc_support_set | (flags & OSC_SUPPORT_MASKS);
 295         capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
 296         capbuf[OSC_SUPPORT_TYPE] = support_set;
 297         capbuf[OSC_CONTROL_TYPE] = OSC_CONTROL_MASKS;
 298
 299         status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
 300         if (ACPI_SUCCESS(status)) {
 301                 root->osc_support_set = support_set;
 302                 root->osc_control_qry = result;
 303                 root->osc_queried = 1;
 304         }
 305         return status;
 306 }
 307
 308 static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
 309 {
 310         acpi_status status;
 311         acpi_handle tmp;
 312
 313         status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
 314         if (ACPI_FAILURE(status))
 315                 return status;
 316         mutex_lock(&osc_lock);
 317         status = acpi_pci_query_osc(root, flags);
 318         mutex_unlock(&osc_lock);
 319         return status;
 320 }
 321
 322 static struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)
 323 {
 324         struct acpi_pci_root *root;
 325         list_for_each_entry(root, &acpi_pci_roots, node) {
 326                 if (root->device->handle == handle)
 327                         return root;
 328         }
 329         return NULL;
 330 }
 331
 332 struct acpi_handle_node {
 333         struct list_head node;
 334         acpi_handle handle;
 335 };
 336
 337 /**
 338  * acpi_get_pci_dev - convert ACPI CA handle to struct pci_dev
 339  * @handle: the handle in question
 340  *
 341  * Given an ACPI CA handle, the desired PCI device is located in the
 342  * list of PCI devices.
 343  *
 344  * If the device is found, its reference count is increased and this
 345  * function returns a pointer to its data structure.  The caller must
 346  * decrement the reference count by calling pci_dev_put().
 347  * If no device is found, %NULL is returned.
 348  */
 349 struct pci_dev *acpi_get_pci_dev(acpi_handle handle)
 350 {
 351         int dev, fn;
 352         unsigned long long adr;
 353         acpi_status status;
 354         acpi_handle phandle;
 355         struct pci_bus *pbus;
 356         struct pci_dev *pdev = NULL;
 357         struct acpi_handle_node *node, *tmp;
 358         struct acpi_pci_root *root;
 359         LIST_HEAD(device_list);
 360
 361         /*
 362          * Walk up the ACPI CA namespace until we reach a PCI root bridge.
 363          */
 364         phandle = handle;
 365         while (!acpi_is_root_bridge(phandle)) {
 366                 node = kzalloc(sizeof(struct acpi_handle_node), GFP_KERNEL);
 367                 if (!node)
 368                         goto out;
 369
 370                 INIT_LIST_HEAD(&node->node);
 371                 node->handle = phandle;
 372                 list_add(&node->node, &device_list);
 373
 374                 status = acpi_get_parent(phandle, &phandle);
 375                 if (ACPI_FAILURE(status))
 376                         goto out;
 377         }
 378
 379         root = acpi_pci_find_root(phandle);
 380         if (!root)
 381                 goto out;
 382
 383         pbus = root->bus;
 384
 385         /*
 386          * Now, walk back down the PCI device tree until we return to our
 387          * original handle. Assumes that everything between the PCI root
 388          * bridge and the device we're looking for must be a P2P bridge.
 389          */
 390         list_for_each_entry(node, &device_list, node) {
 391                 acpi_handle hnd = node->handle;
 392                 status = acpi_evaluate_integer(hnd, "_ADR", NULL, &adr);
 393                 if (ACPI_FAILURE(status))
 394                         goto out;
 395                 dev = (adr >> 16) & 0xffff;
 396                 fn  = adr & 0xffff;
 397
 398                 pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
 399                 if (hnd == handle)
 400                         break;
 401
 402                 pbus = pdev->subordinate;
 403                 pci_dev_put(pdev);
 404         }
 405 out:
 406         list_for_each_entry_safe(node, tmp, &device_list, node)
 407                 kfree(node);
 408
 409         return pdev;
 410 }
 411 EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
 412
 413 /**
 414  * acpi_pci_osc_control_set - commit requested control to Firmware
 415  * @handle: acpi_handle for the target ACPI object
 416  * @flags: driver's requested control bits
 417  *
 418  * Attempt to take control from Firmware on requested control bits.
 419  **/
 420 acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 flags)
 421 {
 422         acpi_status status;
 423         u32 control_req, result, capbuf[3];
 424         acpi_handle tmp;
 425         struct acpi_pci_root *root;
 426
 427         status = acpi_get_handle(handle, "_OSC", &tmp);
 428         if (ACPI_FAILURE(status))
 429                 return status;
 430
 431         control_req = (flags & OSC_CONTROL_MASKS);
 432         if (!control_req)
 433                 return AE_TYPE;
 434
 435         root = acpi_pci_find_root(handle);
 436         if (!root)
 437                 return AE_NOT_EXIST;
 438
 439         mutex_lock(&osc_lock);
 440         /* No need to evaluate _OSC if the control was already granted. */
 441         if ((root->osc_control_set & control_req) == control_req)
 442                 goto out;
 443
 444         /* Need to query controls first before requesting them */
 445         if (!root->osc_queried) {
 446                 status = acpi_pci_query_osc(root, root->osc_support_set);
 447                 if (ACPI_FAILURE(status))
 448                         goto out;
 449         }
 450         if ((root->osc_control_qry & control_req) != control_req) {
 451                 printk(KERN_DEBUG
 452                        "Firmware did not grant requested _OSC control\n");
 453                 status = AE_SUPPORT;
 454                 goto out;
 455         }
 456
 457         capbuf[OSC_QUERY_TYPE] = 0;
 458         capbuf[OSC_SUPPORT_TYPE] = root->osc_support_set;
 459         capbuf[OSC_CONTROL_TYPE] = root->osc_control_set | control_req;
 460         status = acpi_pci_run_osc(handle, capbuf, &result);
 461         if (ACPI_SUCCESS(status))
 462                 root->osc_control_set = result;
 463 out:
 464         mutex_unlock(&osc_lock);
 465         return status;
 466 }
 467 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 468
 469 static int __devinit acpi_pci_root_add(struct acpi_device *device)
 470 {
 471         int result = 0;
 472         struct acpi_pci_root *root = NULL;
 473         struct acpi_pci_root *tmp;
 474         acpi_status status = AE_OK;
 475         unsigned long long value = 0;
 476         acpi_handle handle = NULL;
 477         struct acpi_device *child;
 478         u32 flags, base_flags;
 479
 480
 481         if (!device)
 482                 return -EINVAL;
 483
 484         root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 485         if (!root)
 486                 return -ENOMEM;
 487         INIT_LIST_HEAD(&root->node);
 488
 489         root->device = device;
 490         strcpy(acpi_device_name(device), ACPI_PCI_ROOT_DEVICE_NAME);
 491         strcpy(acpi_device_class(device), ACPI_PCI_ROOT_CLASS);
 492         device->driver_data = root;
 493
 494         /*
 495          * All supported architectures that use ACPI have support for
 496          * PCI domains, so we indicate this in _OSC support capabilities.
 497          */
 498         flags = base_flags = OSC_PCI_SEGMENT_GROUPS_SUPPORT;
 499         acpi_pci_osc_support(root, flags);
 500
 501         /*
 502          * Segment
 503          * -------
 504          * Obtained via _SEG, if exists, otherwise assumed to be zero (0).
 505          */
 506         status = acpi_evaluate_integer(device->handle, METHOD_NAME__SEG, NULL,
 507                                        &value);
 508         switch (status) {
 509         case AE_OK:
 510                 root->id.segment = (u16) value;
 511                 break;
 512         case AE_NOT_FOUND:
 513                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 514                                   "Assuming segment 0 (no _SEG)\n"));
 515                 root->id.segment = 0;
 516                 break;
 517         default:
 518                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SEG"));
 519                 result = -ENODEV;
 520                 goto end;
 521         }
 522
 523         /*
 524          * Bus
 525          * ---
 526          * Obtained via _BBN, if exists, otherwise assumed to be zero (0).
 527          */
 528         status = acpi_evaluate_integer(device->handle, METHOD_NAME__BBN, NULL,
 529                                        &value);
 530         switch (status) {
 531         case AE_OK:
 532                 root->id.bus = (u16) value;
 533                 break;
 534         case AE_NOT_FOUND:
 535                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Assuming bus 0 (no _BBN)\n"));
 536                 root->id.bus = 0;
 537                 break;
 538         default:
 539                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _BBN"));
 540                 result = -ENODEV;
 541                 goto end;
 542         }
 543
 544         /* Some systems have wrong _BBN */
 545         list_for_each_entry(tmp, &acpi_pci_roots, node) {
 546                 if ((tmp->id.segment == root->id.segment)
 547                     && (tmp->id.bus == root->id.bus)) {
 548                         int bus = 0;
 549                         acpi_status status;
 550
 551                         printk(KERN_ERR PREFIX
 552                                     "Wrong _BBN value, reboot"
 553                                     " and use option 'pci=noacpi'\n");
 554
 555                         status = try_get_root_bridge_busnr(device->handle, &bus);
 556                         if (ACPI_FAILURE(status))
 557                                 break;
 558                         if (bus != root->id.bus) {
 559                                 printk(KERN_INFO PREFIX
 560                                        "PCI _CRS %d overrides _BBN 0\n", bus);
 561                                 root->id.bus = bus;
 562                         }
 563                         break;
 564                 }
 565         }
 566         /*
 567          * Device & Function
 568          * -----------------
 569          * Obtained from _ADR (which has already been evaluated for us).
 570          */
 571         root->id.device = device->pnp.bus_address >> 16;
 572         root->id.function = device->pnp.bus_address & 0xFFFF;
 573
 574         /*
 575          * TBD: Need PCI interface for enumeration/configuration of roots.
 576          */
 577
 578         /* TBD: Locking */
 579         list_add_tail(&root->node, &acpi_pci_roots);
 580
 581         printk(KERN_INFO PREFIX "%s [%s] (%04x:%02x)\n",
 582                acpi_device_name(device), acpi_device_bid(device),
 583                root->id.segment, root->id.bus);
 584
 585         /*
 586          * Scan the Root Bridge
 587          * --------------------
 588          * Must do this prior to any attempt to bind the root device, as the
 589          * PCI namespace does not get created until this call is made (and
 590          * thus the root bridge's pci_dev does not exist).
 591          */
 592         root->bus = pci_acpi_scan_root(device, root->id.segment, root->id.bus);
 593         if (!root->bus) {
 594                 printk(KERN_ERR PREFIX
 595                             "Bus %04x:%02x not present in PCI namespace\n",
 596                             root->id.segment, root->id.bus);
 597                 result = -ENODEV;
 598                 goto end;
 599         }
 600
 601         /*
 602          * Attach ACPI-PCI Context
 603          * -----------------------
 604          * Thus binding the ACPI and PCI devices.
 605          */
 606         result = acpi_pci_bind_root(device, &root->id, root->bus);
 607         if (result)
 608                 goto end;
 609
 610         /*
 611          * PCI Routing Table
 612          * -----------------
 613          * Evaluate and parse _PRT, if exists.
 614          */
 615         status = acpi_get_handle(device->handle, METHOD_NAME__PRT, &handle);
 616         if (ACPI_SUCCESS(status))
 617                 result = acpi_pci_irq_add_prt(device->handle, root->id.segment,
 618                                               root->id.bus);
 619
 620         /*
 621          * Scan and bind all _ADR-Based Devices
 622          */
 623         list_for_each_entry(child, &device->children, node)
 624                 acpi_pci_bridge_scan(child);
 625
 626         /* Indicate support for various _OSC capabilities. */
 627         if (pci_ext_cfg_avail(root->bus->self))
 628                 flags |= OSC_EXT_PCI_CONFIG_SUPPORT;
 629         if (pcie_aspm_enabled())
 630                 flags |= OSC_ACTIVE_STATE_PWR_SUPPORT |
 631                         OSC_CLOCK_PWR_CAPABILITY_SUPPORT;
 632         if (pci_msi_enabled())
 633                 flags |= OSC_MSI_SUPPORT;
 634         if (flags != base_flags)
 635                 acpi_pci_osc_support(root, flags);
 636
 637       end:
 638         if (result) {
 639                 if (!list_empty(&root->node))
 640                         list_del(&root->node);
 641                 kfree(root);
 642         }
 643
 644         return result;
 645 }
 646
 647 static int acpi_pci_root_start(struct acpi_device *device)
 648 {
 649         struct acpi_pci_root *root;
 650
 651
 652         list_for_each_entry(root, &acpi_pci_roots, node) {
 653                 if (root->device == device) {
 654                         pci_bus_add_devices(root->bus);
 655                         return 0;
 656                 }
 657         }
 658         return -ENODEV;
 659 }
 660
 661 static int acpi_pci_root_remove(struct acpi_device *device, int type)
 662 {
 663         struct acpi_pci_root *root = NULL;
 664
 665
 666         if (!device || !acpi_driver_data(device))
 667                 return -EINVAL;
 668
 669         root = acpi_driver_data(device);
 670
 671         kfree(root);
 672
 673         return 0;
 674 }
 675
 676 static int __init acpi_pci_root_init(void)
 677 {
 678         if (acpi_pci_disabled)
 679                 return 0;
 680
 681         if (acpi_bus_register_driver(&acpi_pci_root_driver) < 0)
 682                 return -ENODEV;
 683
 684         return 0;
 685 }
 686
 687 subsys_initcall(acpi_pci_root_init);