drivers/acpi/pci_link.c

   1 /*
   2  *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
   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  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
   7  *
   8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License as published by
  12  *  the Free Software Foundation; either version 2 of the License, or (at
  13  *  your option) any later version.
  14  *
  15  *  This program is distributed in the hope that it will be useful, but
  16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  *  General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License along
  21  *  with this program; if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23  *
  24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25  *
  26  * TBD:
  27  *      1. Support more than one IRQ resource entry per link device (index).
  28  *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
  29  *         for IRQ management (e.g. start()->_SRS).
  30  */
  31
  32 #include <linux/syscore_ops.h>
  33 #include <linux/kernel.h>
  34 #include <linux/module.h>
  35 #include <linux/init.h>
  36 #include <linux/types.h>
  37 #include <linux/spinlock.h>
  38 #include <linux/pm.h>
  39 #include <linux/pci.h>
  40 #include <linux/mutex.h>
  41 #include <linux/slab.h>
  42
  43 #include <acpi/acpi_bus.h>
  44 #include <acpi/acpi_drivers.h>
  45
  46 #define PREFIX "ACPI: "
  47
  48 #define _COMPONENT                      ACPI_PCI_COMPONENT
  49 ACPI_MODULE_NAME("pci_link");
  50 #define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  51 #define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
  52 #define ACPI_PCI_LINK_FILE_INFO         "info"
  53 #define ACPI_PCI_LINK_FILE_STATUS       "state"
  54 #define ACPI_PCI_LINK_MAX_POSSIBLE      16
  55
  56 static int acpi_pci_link_add(struct acpi_device *device);
  57 static int acpi_pci_link_remove(struct acpi_device *device, int type);
  58
  59 static const struct acpi_device_id link_device_ids[] = {
  60         {"PNP0C0F", 0},
  61         {"", 0},
  62 };
  63 MODULE_DEVICE_TABLE(acpi, link_device_ids);
  64
  65 static struct acpi_driver acpi_pci_link_driver = {
  66         .name = "pci_link",
  67         .class = ACPI_PCI_LINK_CLASS,
  68         .ids = link_device_ids,
  69         .ops = {
  70                 .add = acpi_pci_link_add,
  71                 .remove = acpi_pci_link_remove,
  72         },
  73 };
  74
  75 /*
  76  * If a link is initialized, we never change its active and initialized
  77  * later even the link is disable. Instead, we just repick the active irq
  78  */
  79 struct acpi_pci_link_irq {
  80         u8 active;              /* Current IRQ */
  81         u8 triggering;          /* All IRQs */
  82         u8 polarity;            /* All IRQs */
  83         u8 resource_type;
  84         u8 possible_count;
  85         u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  86         u8 initialized:1;
  87         u8 reserved:7;
  88 };
  89
  90 struct acpi_pci_link {
  91         struct list_head                list;
  92         struct acpi_device              *device;
  93         struct acpi_pci_link_irq        irq;
  94         int                             refcnt;
  95 };
  96
  97 static LIST_HEAD(acpi_link_list);
  98 static DEFINE_MUTEX(acpi_link_lock);
  99
 100 /* --------------------------------------------------------------------------
 101                             PCI Link Device Management
 102    -------------------------------------------------------------------------- */
 103
 104 /*
 105  * set context (link) possible list from resource list
 106  */
 107 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
 108                                                 void *context)
 109 {
 110         struct acpi_pci_link *link = context;
 111         u32 i;
 112
 113         switch (resource->type) {
 114         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 115         case ACPI_RESOURCE_TYPE_END_TAG:
 116                 return AE_OK;
 117         case ACPI_RESOURCE_TYPE_IRQ:
 118                 {
 119                         struct acpi_resource_irq *p = &resource->data.irq;
 120                         if (!p || !p->interrupt_count) {
 121                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 122                                                   "Blank _PRS IRQ resource\n"));
 123                                 return AE_OK;
 124                         }
 125                         for (i = 0;
 126                              (i < p->interrupt_count
 127                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 128                                 if (!p->interrupts[i]) {
 129                                         printk(KERN_WARNING PREFIX
 130                                                "Invalid _PRS IRQ %d\n",
 131                                                p->interrupts[i]);
 132                                         continue;
 133                                 }
 134                                 link->irq.possible[i] = p->interrupts[i];
 135                                 link->irq.possible_count++;
 136                         }
 137                         link->irq.triggering = p->triggering;
 138                         link->irq.polarity = p->polarity;
 139                         link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 140                         break;
 141                 }
 142         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 143                 {
 144                         struct acpi_resource_extended_irq *p =
 145                             &resource->data.extended_irq;
 146                         if (!p || !p->interrupt_count) {
 147                                 printk(KERN_WARNING PREFIX
 148                                               "Blank _PRS EXT IRQ resource\n");
 149                                 return AE_OK;
 150                         }
 151                         for (i = 0;
 152                              (i < p->interrupt_count
 153                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 154                                 if (!p->interrupts[i]) {
 155                                         printk(KERN_WARNING PREFIX
 156                                                "Invalid _PRS IRQ %d\n",
 157                                                p->interrupts[i]);
 158                                         continue;
 159                                 }
 160                                 link->irq.possible[i] = p->interrupts[i];
 161                                 link->irq.possible_count++;
 162                         }
 163                         link->irq.triggering = p->triggering;
 164                         link->irq.polarity = p->polarity;
 165                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 166                         break;
 167                 }
 168         default:
 169                 printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
 170                        resource->type);
 171                 return AE_OK;
 172         }
 173
 174         return AE_CTRL_TERMINATE;
 175 }
 176
 177 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 178 {
 179         acpi_status status;
 180
 181         status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
 182                                      acpi_pci_link_check_possible, link);
 183         if (ACPI_FAILURE(status)) {
 184                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
 185                 return -ENODEV;
 186         }
 187
 188         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 189                           "Found %d possible IRQs\n",
 190                           link->irq.possible_count));
 191
 192         return 0;
 193 }
 194
 195 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 196                                                void *context)
 197 {
 198         int *irq = context;
 199
 200         switch (resource->type) {
 201         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 202         case ACPI_RESOURCE_TYPE_END_TAG:
 203                 return AE_OK;
 204         case ACPI_RESOURCE_TYPE_IRQ:
 205                 {
 206                         struct acpi_resource_irq *p = &resource->data.irq;
 207                         if (!p || !p->interrupt_count) {
 208                                 /*
 209                                  * IRQ descriptors may have no IRQ# bits set,
 210                                  * particularly those those w/ _STA disabled
 211                                  */
 212                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 213                                                   "Blank _CRS IRQ resource\n"));
 214                                 return AE_OK;
 215                         }
 216                         *irq = p->interrupts[0];
 217                         break;
 218                 }
 219         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 220                 {
 221                         struct acpi_resource_extended_irq *p =
 222                             &resource->data.extended_irq;
 223                         if (!p || !p->interrupt_count) {
 224                                 /*
 225                                  * extended IRQ descriptors must
 226                                  * return at least 1 IRQ
 227                                  */
 228                                 printk(KERN_WARNING PREFIX
 229                                               "Blank _CRS EXT IRQ resource\n");
 230                                 return AE_OK;
 231                         }
 232                         *irq = p->interrupts[0];
 233                         break;
 234                 }
 235                 break;
 236         default:
 237                 printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
 238                        resource->type);
 239                 return AE_OK;
 240         }
 241
 242         return AE_CTRL_TERMINATE;
 243 }
 244
 245 /*
 246  * Run _CRS and set link->irq.active
 247  *
 248  * return value:
 249  * 0 - success
 250  * !0 - failure
 251  */
 252 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 253 {
 254         int result = 0;
 255         acpi_status status;
 256         int irq = 0;
 257
 258         link->irq.active = 0;
 259
 260         /* in practice, status disabled is meaningless, ignore it */
 261         if (acpi_strict) {
 262                 /* Query _STA, set link->device->status */
 263                 result = acpi_bus_get_status(link->device);
 264                 if (result) {
 265                         printk(KERN_ERR PREFIX "Unable to read status\n");
 266                         goto end;
 267                 }
 268
 269                 if (!link->device->status.enabled) {
 270                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
 271                         return 0;
 272                 }
 273         }
 274
 275         /*
 276          * Query and parse _CRS to get the current IRQ assignment.
 277          */
 278
 279         status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
 280                                      acpi_pci_link_check_current, &irq);
 281         if (ACPI_FAILURE(status)) {
 282                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
 283                 result = -ENODEV;
 284                 goto end;
 285         }
 286
 287         if (acpi_strict && !irq) {
 288                 printk(KERN_ERR PREFIX "_CRS returned 0\n");
 289                 result = -ENODEV;
 290         }
 291
 292         link->irq.active = irq;
 293
 294         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
 295
 296       end:
 297         return result;
 298 }
 299
 300 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 301 {
 302         int result;
 303         acpi_status status;
 304         struct {
 305                 struct acpi_resource res;
 306                 struct acpi_resource end;
 307         } *resource;
 308         struct acpi_buffer buffer = { 0, NULL };
 309
 310         if (!irq)
 311                 return -EINVAL;
 312
 313         resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
 314         if (!resource)
 315                 return -ENOMEM;
 316
 317         buffer.length = sizeof(*resource) + 1;
 318         buffer.pointer = resource;
 319
 320         switch (link->irq.resource_type) {
 321         case ACPI_RESOURCE_TYPE_IRQ:
 322                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 323                 resource->res.length = sizeof(struct acpi_resource);
 324                 resource->res.data.irq.triggering = link->irq.triggering;
 325                 resource->res.data.irq.polarity =
 326                     link->irq.polarity;
 327                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 328                         resource->res.data.irq.sharable =
 329                             ACPI_EXCLUSIVE;
 330                 else
 331                         resource->res.data.irq.sharable = ACPI_SHARED;
 332                 resource->res.data.irq.interrupt_count = 1;
 333                 resource->res.data.irq.interrupts[0] = irq;
 334                 break;
 335
 336         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 337                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 338                 resource->res.length = sizeof(struct acpi_resource);
 339                 resource->res.data.extended_irq.producer_consumer =
 340                     ACPI_CONSUMER;
 341                 resource->res.data.extended_irq.triggering =
 342                     link->irq.triggering;
 343                 resource->res.data.extended_irq.polarity =
 344                     link->irq.polarity;
 345                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 346                         resource->res.data.irq.sharable =
 347                             ACPI_EXCLUSIVE;
 348                 else
 349                         resource->res.data.irq.sharable = ACPI_SHARED;
 350                 resource->res.data.extended_irq.interrupt_count = 1;
 351                 resource->res.data.extended_irq.interrupts[0] = irq;
 352                 /* ignore resource_source, it's optional */
 353                 break;
 354         default:
 355                 printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
 356                 result = -EINVAL;
 357                 goto end;
 358
 359         }
 360         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 361
 362         /* Attempt to set the resource */
 363         status = acpi_set_current_resources(link->device->handle, &buffer);
 364
 365         /* check for total failure */
 366         if (ACPI_FAILURE(status)) {
 367                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
 368                 result = -ENODEV;
 369                 goto end;
 370         }
 371
 372         /* Query _STA, set device->status */
 373         result = acpi_bus_get_status(link->device);
 374         if (result) {
 375                 printk(KERN_ERR PREFIX "Unable to read status\n");
 376                 goto end;
 377         }
 378         if (!link->device->status.enabled) {
 379                 printk(KERN_WARNING PREFIX
 380                               "%s [%s] disabled and referenced, BIOS bug\n",
 381                               acpi_device_name(link->device),
 382                               acpi_device_bid(link->device));
 383         }
 384
 385         /* Query _CRS, set link->irq.active */
 386         result = acpi_pci_link_get_current(link);
 387         if (result) {
 388                 goto end;
 389         }
 390
 391         /*
 392          * Is current setting not what we set?
 393          * set link->irq.active
 394          */
 395         if (link->irq.active != irq) {
 396                 /*
 397                  * policy: when _CRS doesn't return what we just _SRS
 398                  * assume _SRS worked and override _CRS value.
 399                  */
 400                 printk(KERN_WARNING PREFIX
 401                               "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 402                               acpi_device_name(link->device),
 403                               acpi_device_bid(link->device), link->irq.active, irq);
 404                 link->irq.active = irq;
 405         }
 406
 407         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 408
 409       end:
 410         kfree(resource);
 411         return result;
 412 }
 413
 414 /* --------------------------------------------------------------------------
 415                             PCI Link IRQ Management
 416    -------------------------------------------------------------------------- */
 417
 418 /*
 419  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 420  * Link Devices to move the PIRQs around to minimize sharing.
 421  *
 422  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 423  * that the BIOS has already set to active.  This is necessary because
 424  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 425  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 426  * even if acpi_irq_nobalance is set.
 427  *
 428  * A tables of penalties avoids directing PCI interrupts to well known
 429  * ISA IRQs. Boot params are available to over-ride the default table:
 430  *
 431  * List interrupts that are free for PCI use.
 432  * acpi_irq_pci=n[,m]
 433  *
 434  * List interrupts that should not be used for PCI:
 435  * acpi_irq_isa=n[,m]
 436  *
 437  * Note that PCI IRQ routers have a list of possible IRQs,
 438  * which may not include the IRQs this table says are available.
 439  *
 440  * Since this heuristic can't tell the difference between a link
 441  * that no device will attach to, vs. a link which may be shared
 442  * by multiple active devices -- it is not optimal.
 443  *
 444  * If interrupt performance is that important, get an IO-APIC system
 445  * with a pin dedicated to each device.  Or for that matter, an MSI
 446  * enabled system.
 447  */
 448
 449 #define ACPI_MAX_IRQS           256
 450 #define ACPI_MAX_ISA_IRQ        16
 451
 452 #define PIRQ_PENALTY_PCI_AVAILABLE      (0)
 453 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 454 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
 455 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 456 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 457 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 458
 459 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 460         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 461         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 462         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 463         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 464         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 465         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 466         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 467         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 468         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 469         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
 470         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
 471         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
 472         PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
 473         PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
 474         PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
 475         PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
 476         /* >IRQ15 */
 477 };
 478
 479 int __init acpi_irq_penalty_init(void)
 480 {
 481         struct acpi_pci_link *link;
 482         int i;
 483
 484         /*
 485          * Update penalties to facilitate IRQ balancing.
 486          */
 487         list_for_each_entry(link, &acpi_link_list, list) {
 488
 489                 /*
 490                  * reflect the possible and active irqs in the penalty table --
 491                  * useful for breaking ties.
 492                  */
 493                 if (link->irq.possible_count) {
 494                         int penalty =
 495                             PIRQ_PENALTY_PCI_POSSIBLE /
 496                             link->irq.possible_count;
 497
 498                         for (i = 0; i < link->irq.possible_count; i++) {
 499                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
 500                                         acpi_irq_penalty[link->irq.
 501                                                          possible[i]] +=
 502                                             penalty;
 503                         }
 504
 505                 } else if (link->irq.active) {
 506                         acpi_irq_penalty[link->irq.active] +=
 507                             PIRQ_PENALTY_PCI_POSSIBLE;
 508                 }
 509         }
 510         /* Add a penalty for the SCI */
 511         acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
 512         return 0;
 513 }
 514
 515 static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 516
 517 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 518 {
 519         int irq;
 520         int i;
 521
 522         if (link->irq.initialized) {
 523                 if (link->refcnt == 0)
 524                         /* This means the link is disabled but initialized */
 525                         acpi_pci_link_set(link, link->irq.active);
 526                 return 0;
 527         }
 528
 529         /*
 530          * search for active IRQ in list of possible IRQs.
 531          */
 532         for (i = 0; i < link->irq.possible_count; ++i) {
 533                 if (link->irq.active == link->irq.possible[i])
 534                         break;
 535         }
 536         /*
 537          * forget active IRQ that is not in possible list
 538          */
 539         if (i == link->irq.possible_count) {
 540                 if (acpi_strict)
 541                         printk(KERN_WARNING PREFIX "_CRS %d not found"
 542                                       " in _PRS\n", link->irq.active);
 543                 link->irq.active = 0;
 544         }
 545
 546         /*
 547          * if active found, use it; else pick entry from end of possible list.
 548          */
 549         if (link->irq.active)
 550                 irq = link->irq.active;
 551         else
 552                 irq = link->irq.possible[link->irq.possible_count - 1];
 553
 554         if (acpi_irq_balance || !link->irq.active) {
 555                 /*
 556                  * Select the best IRQ.  This is done in reverse to promote
 557                  * the use of IRQs 9, 10, 11, and >15.
 558                  */
 559                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 560                         if (acpi_irq_penalty[irq] >
 561                             acpi_irq_penalty[link->irq.possible[i]])
 562                                 irq = link->irq.possible[i];
 563                 }
 564         }
 565
 566         /* Attempt to enable the link device at this IRQ. */
 567         if (acpi_pci_link_set(link, irq)) {
 568                 printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
 569                             "Try pci=noacpi or acpi=off\n",
 570                             acpi_device_name(link->device),
 571                             acpi_device_bid(link->device));
 572                 return -ENODEV;
 573         } else {
 574                 acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 575                 printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
 576                        acpi_device_name(link->device),
 577                        acpi_device_bid(link->device), link->irq.active);
 578         }
 579
 580         link->irq.initialized = 1;
 581         return 0;
 582 }
 583
 584 /*
 585  * acpi_pci_link_allocate_irq
 586  * success: return IRQ >= 0
 587  * failure: return -1
 588  */
 589 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 590                                int *polarity, char **name)
 591 {
 592         int result;
 593         struct acpi_device *device;
 594         struct acpi_pci_link *link;
 595
 596         result = acpi_bus_get_device(handle, &device);
 597         if (result) {
 598                 printk(KERN_ERR PREFIX "Invalid link device\n");
 599                 return -1;
 600         }
 601
 602         link = acpi_driver_data(device);
 603         if (!link) {
 604                 printk(KERN_ERR PREFIX "Invalid link context\n");
 605                 return -1;
 606         }
 607
 608         /* TBD: Support multiple index (IRQ) entries per Link Device */
 609         if (index) {
 610                 printk(KERN_ERR PREFIX "Invalid index %d\n", index);
 611                 return -1;
 612         }
 613
 614         mutex_lock(&acpi_link_lock);
 615         if (acpi_pci_link_allocate(link)) {
 616                 mutex_unlock(&acpi_link_lock);
 617                 return -1;
 618         }
 619
 620         if (!link->irq.active) {
 621                 mutex_unlock(&acpi_link_lock);
 622                 printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
 623                 return -1;
 624         }
 625         link->refcnt++;
 626         mutex_unlock(&acpi_link_lock);
 627
 628         if (triggering)
 629                 *triggering = link->irq.triggering;
 630         if (polarity)
 631                 *polarity = link->irq.polarity;
 632         if (name)
 633                 *name = acpi_device_bid(link->device);
 634         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 635                           "Link %s is referenced\n",
 636                           acpi_device_bid(link->device)));
 637         return (link->irq.active);
 638 }
 639
 640 /*
 641  * We don't change link's irq information here.  After it is reenabled, we
 642  * continue use the info
 643  */
 644 int acpi_pci_link_free_irq(acpi_handle handle)
 645 {
 646         struct acpi_device *device;
 647         struct acpi_pci_link *link;
 648         acpi_status result;
 649
 650         result = acpi_bus_get_device(handle, &device);
 651         if (result) {
 652                 printk(KERN_ERR PREFIX "Invalid link device\n");
 653                 return -1;
 654         }
 655
 656         link = acpi_driver_data(device);
 657         if (!link) {
 658                 printk(KERN_ERR PREFIX "Invalid link context\n");
 659                 return -1;
 660         }
 661
 662         mutex_lock(&acpi_link_lock);
 663         if (!link->irq.initialized) {
 664                 mutex_unlock(&acpi_link_lock);
 665                 printk(KERN_ERR PREFIX "Link isn't initialized\n");
 666                 return -1;
 667         }
 668 #ifdef  FUTURE_USE
 669         /*
 670          * The Link reference count allows us to _DISable an unused link
 671          * and suspend time, and set it again  on resume.
 672          * However, 2.6.12 still has irq_router.resume
 673          * which blindly restores the link state.
 674          * So we disable the reference count method
 675          * to prevent duplicate acpi_pci_link_set()
 676          * which would harm some systems
 677          */
 678         link->refcnt--;
 679 #endif
 680         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 681                           "Link %s is dereferenced\n",
 682                           acpi_device_bid(link->device)));
 683
 684         if (link->refcnt == 0)
 685                 acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 686
 687         mutex_unlock(&acpi_link_lock);
 688         return (link->irq.active);
 689 }
 690
 691 /* --------------------------------------------------------------------------
 692                                  Driver Interface
 693    -------------------------------------------------------------------------- */
 694
 695 static int acpi_pci_link_add(struct acpi_device *device)
 696 {
 697         int result;
 698         struct acpi_pci_link *link;
 699         int i;
 700         int found = 0;
 701
 702         link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 703         if (!link)
 704                 return -ENOMEM;
 705
 706         link->device = device;
 707         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 708         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 709         device->driver_data = link;
 710
 711         mutex_lock(&acpi_link_lock);
 712         result = acpi_pci_link_get_possible(link);
 713         if (result)
 714                 goto end;
 715
 716         /* query and set link->irq.active */
 717         acpi_pci_link_get_current(link);
 718
 719         printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 720                acpi_device_bid(device));
 721         for (i = 0; i < link->irq.possible_count; i++) {
 722                 if (link->irq.active == link->irq.possible[i]) {
 723                         printk(KERN_CONT " *%d", link->irq.possible[i]);
 724                         found = 1;
 725                 } else
 726                         printk(KERN_CONT " %d", link->irq.possible[i]);
 727         }
 728
 729         printk(KERN_CONT ")");
 730
 731         if (!found)
 732                 printk(KERN_CONT " *%d", link->irq.active);
 733
 734         if (!link->device->status.enabled)
 735                 printk(KERN_CONT ", disabled.");
 736
 737         printk(KERN_CONT "\n");
 738
 739         list_add_tail(&link->list, &acpi_link_list);
 740
 741       end:
 742         /* disable all links -- to be activated on use */
 743         acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
 744         mutex_unlock(&acpi_link_lock);
 745
 746         if (result)
 747                 kfree(link);
 748
 749         return result;
 750 }
 751
 752 static int acpi_pci_link_resume(struct acpi_pci_link *link)
 753 {
 754         if (link->refcnt && link->irq.active && link->irq.initialized)
 755                 return (acpi_pci_link_set(link, link->irq.active));
 756
 757         return 0;
 758 }
 759
 760 static void irqrouter_resume(void)
 761 {
 762         struct acpi_pci_link *link;
 763
 764         list_for_each_entry(link, &acpi_link_list, list) {
 765                 acpi_pci_link_resume(link);
 766         }
 767 }
 768
 769 static int acpi_pci_link_remove(struct acpi_device *device, int type)
 770 {
 771         struct acpi_pci_link *link;
 772
 773         link = acpi_driver_data(device);
 774
 775         mutex_lock(&acpi_link_lock);
 776         list_del(&link->list);
 777         mutex_unlock(&acpi_link_lock);
 778
 779         kfree(link);
 780         return 0;
 781 }
 782
 783 /*
 784  * modify acpi_irq_penalty[] from cmdline
 785  */
 786 static int __init acpi_irq_penalty_update(char *str, int used)
 787 {
 788         int i;
 789
 790         for (i = 0; i < 16; i++) {
 791                 int retval;
 792                 int irq;
 793
 794                 retval = get_option(&str, &irq);
 795
 796                 if (!retval)
 797                         break;  /* no number found */
 798
 799                 if (irq < 0)
 800                         continue;
 801
 802                 if (irq >= ARRAY_SIZE(acpi_irq_penalty))
 803                         continue;
 804
 805                 if (used)
 806                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 807                 else
 808                         acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 809
 810                 if (retval != 2)        /* no next number */
 811                         break;
 812         }
 813         return 1;
 814 }
 815
 816 /*
 817  * We'd like PNP to call this routine for the
 818  * single ISA_USED value for each legacy device.
 819  * But instead it calls us with each POSSIBLE setting.
 820  * There is no ISA_POSSIBLE weight, so we simply use
 821  * the (small) PCI_USING penalty.
 822  */
 823 void acpi_penalize_isa_irq(int irq, int active)
 824 {
 825         if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
 826                 if (active)
 827                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 828                 else
 829                         acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
 830         }
 831 }
 832
 833 /*
 834  * Over-ride default table to reserve additional IRQs for use by ISA
 835  * e.g. acpi_irq_isa=5
 836  * Useful for telling ACPI how not to interfere with your ISA sound card.
 837  */
 838 static int __init acpi_irq_isa(char *str)
 839 {
 840         return acpi_irq_penalty_update(str, 1);
 841 }
 842
 843 __setup("acpi_irq_isa=", acpi_irq_isa);
 844
 845 /*
 846  * Over-ride default table to free additional IRQs for use by PCI
 847  * e.g. acpi_irq_pci=7,15
 848  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 849  */
 850 static int __init acpi_irq_pci(char *str)
 851 {
 852         return acpi_irq_penalty_update(str, 0);
 853 }
 854
 855 __setup("acpi_irq_pci=", acpi_irq_pci);
 856
 857 static int __init acpi_irq_nobalance_set(char *str)
 858 {
 859         acpi_irq_balance = 0;
 860         return 1;
 861 }
 862
 863 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 864
 865 static int __init acpi_irq_balance_set(char *str)
 866 {
 867         acpi_irq_balance = 1;
 868         return 1;
 869 }
 870
 871 __setup("acpi_irq_balance", acpi_irq_balance_set);
 872
 873 static struct syscore_ops irqrouter_syscore_ops = {
 874         .resume = irqrouter_resume,
 875 };
 876
 877 static int __init irqrouter_init_ops(void)
 878 {
 879         if (!acpi_disabled && !acpi_noirq)
 880                 register_syscore_ops(&irqrouter_syscore_ops);
 881
 882         return 0;
 883 }
 884
 885 device_initcall(irqrouter_init_ops);
 886
 887 static int __init acpi_pci_link_init(void)
 888 {
 889         if (acpi_noirq)
 890                 return 0;
 891
 892         if (acpi_irq_balance == -1) {
 893                 /* no command line switch: enable balancing in IOAPIC mode */
 894                 if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 895                         acpi_irq_balance = 1;
 896                 else
 897                         acpi_irq_balance = 0;
 898         }
 899
 900         if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
 901                 return -ENODEV;
 902
 903         return 0;
 904 }
 905
 906 subsys_initcall(acpi_pci_link_init);