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