drivers/acpi/pci_link.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
   4  *
   5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
   8  *
   9  * TBD:
  10  *      1. Support more than one IRQ resource entry per link device (index).
  11  *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
  12  *         for IRQ management (e.g. start()->_SRS).
  13  */
  14
  15 #define pr_fmt(fmt) "ACPI: PCI: " fmt
  16
  17 #include <linux/syscore_ops.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/init.h>
  21 #include <linux/types.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/pm.h>
  24 #include <linux/pci.h>
  25 #include <linux/mutex.h>
  26 #include <linux/slab.h>
  27 #include <linux/acpi.h>
  28 #include <linux/irq.h>
  29
  30 #include "internal.h"
  31
  32 #define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  33 #define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
  34 #define ACPI_PCI_LINK_MAX_POSSIBLE      16
  35
  36 static int acpi_pci_link_add(struct acpi_device *device,
  37                              const struct acpi_device_id *not_used);
  38 static void acpi_pci_link_remove(struct acpi_device *device);
  39
  40 static const struct acpi_device_id link_device_ids[] = {
  41         {"PNP0C0F", 0},
  42         {"", 0},
  43 };
  44
  45 static struct acpi_scan_handler pci_link_handler = {
  46         .ids = link_device_ids,
  47         .attach = acpi_pci_link_add,
  48         .detach = acpi_pci_link_remove,
  49 };
  50
  51 /*
  52  * If a link is initialized, we never change its active and initialized
  53  * later even the link is disable. Instead, we just repick the active irq
  54  */
  55 struct acpi_pci_link_irq {
  56         u32 active;             /* Current IRQ */
  57         u8 triggering;          /* All IRQs */
  58         u8 polarity;            /* All IRQs */
  59         u8 resource_type;
  60         u8 possible_count;
  61         u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  62         u8 initialized:1;
  63         u8 reserved:7;
  64 };
  65
  66 struct acpi_pci_link {
  67         struct list_head                list;
  68         struct acpi_device              *device;
  69         struct acpi_pci_link_irq        irq;
  70         int                             refcnt;
  71 };
  72
  73 static LIST_HEAD(acpi_link_list);
  74 static DEFINE_MUTEX(acpi_link_lock);
  75 static int sci_irq = -1, sci_penalty;
  76
  77 /* --------------------------------------------------------------------------
  78                             PCI Link Device Management
  79    -------------------------------------------------------------------------- */
  80
  81 /*
  82  * set context (link) possible list from resource list
  83  */
  84 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
  85                                                 void *context)
  86 {
  87         struct acpi_pci_link *link = context;
  88         acpi_handle handle = link->device->handle;
  89         u32 i;
  90
  91         switch (resource->type) {
  92         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  93         case ACPI_RESOURCE_TYPE_END_TAG:
  94                 return AE_OK;
  95         case ACPI_RESOURCE_TYPE_IRQ:
  96                 {
  97                         struct acpi_resource_irq *p = &resource->data.irq;
  98                         if (!p->interrupt_count) {
  99                                 acpi_handle_debug(handle,
 100                                                   "Blank _PRS IRQ resource\n");
 101                                 return AE_OK;
 102                         }
 103                         for (i = 0;
 104                              (i < p->interrupt_count
 105                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 106                                 if (!p->interrupts[i]) {
 107                                         acpi_handle_debug(handle,
 108                                                           "Invalid _PRS IRQ %d\n",
 109                                                           p->interrupts[i]);
 110                                         continue;
 111                                 }
 112                                 link->irq.possible[i] = p->interrupts[i];
 113                                 link->irq.possible_count++;
 114                         }
 115                         link->irq.triggering = p->triggering;
 116                         link->irq.polarity = p->polarity;
 117                         link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 118                         break;
 119                 }
 120         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 121                 {
 122                         struct acpi_resource_extended_irq *p =
 123                             &resource->data.extended_irq;
 124                         if (!p->interrupt_count) {
 125                                 acpi_handle_debug(handle,
 126                                                   "Blank _PRS EXT IRQ resource\n");
 127                                 return AE_OK;
 128                         }
 129                         for (i = 0;
 130                              (i < p->interrupt_count
 131                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 132                                 if (!p->interrupts[i]) {
 133                                         acpi_handle_debug(handle,
 134                                                           "Invalid _PRS IRQ %d\n",
 135                                                           p->interrupts[i]);
 136                                         continue;
 137                                 }
 138                                 link->irq.possible[i] = p->interrupts[i];
 139                                 link->irq.possible_count++;
 140                         }
 141                         link->irq.triggering = p->triggering;
 142                         link->irq.polarity = p->polarity;
 143                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 144                         break;
 145                 }
 146         default:
 147                 acpi_handle_debug(handle, "_PRS resource type 0x%x is not IRQ\n",
 148                                   resource->type);
 149                 return AE_OK;
 150         }
 151
 152         return AE_CTRL_TERMINATE;
 153 }
 154
 155 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 156 {
 157         acpi_handle handle = link->device->handle;
 158         acpi_status status;
 159
 160         status = acpi_walk_resources(handle, METHOD_NAME__PRS,
 161                                      acpi_pci_link_check_possible, link);
 162         if (ACPI_FAILURE(status)) {
 163                 acpi_handle_debug(handle, "_PRS not present or invalid");
 164                 return 0;
 165         }
 166
 167         acpi_handle_debug(handle, "Found %d possible IRQs\n",
 168                           link->irq.possible_count);
 169
 170         return 0;
 171 }
 172
 173 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 174                                                void *context)
 175 {
 176         int *irq = context;
 177
 178         switch (resource->type) {
 179         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 180         case ACPI_RESOURCE_TYPE_END_TAG:
 181                 return AE_OK;
 182         case ACPI_RESOURCE_TYPE_IRQ:
 183                 {
 184                         struct acpi_resource_irq *p = &resource->data.irq;
 185                         if (!p->interrupt_count) {
 186                                 /*
 187                                  * IRQ descriptors may have no IRQ# bits set,
 188                                  * particularly those w/ _STA disabled
 189                                  */
 190                                 pr_debug("Blank _CRS IRQ resource\n");
 191                                 return AE_OK;
 192                         }
 193                         *irq = p->interrupts[0];
 194                         break;
 195                 }
 196         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 197                 {
 198                         struct acpi_resource_extended_irq *p =
 199                             &resource->data.extended_irq;
 200                         if (!p->interrupt_count) {
 201                                 /*
 202                                  * extended IRQ descriptors must
 203                                  * return at least 1 IRQ
 204                                  */
 205                                 pr_debug("Blank _CRS EXT IRQ resource\n");
 206                                 return AE_OK;
 207                         }
 208                         *irq = p->interrupts[0];
 209                         break;
 210                 }
 211                 break;
 212         default:
 213                 pr_debug("_CRS resource type 0x%x is not IRQ\n",
 214                          resource->type);
 215                 return AE_OK;
 216         }
 217
 218         return AE_CTRL_TERMINATE;
 219 }
 220
 221 /*
 222  * Run _CRS and set link->irq.active
 223  *
 224  * return value:
 225  * 0 - success
 226  * !0 - failure
 227  */
 228 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 229 {
 230         acpi_handle handle = link->device->handle;
 231         acpi_status status;
 232         int result = 0;
 233         int irq = 0;
 234
 235         link->irq.active = 0;
 236
 237         /* in practice, status disabled is meaningless, ignore it */
 238         if (acpi_strict) {
 239                 /* Query _STA, set link->device->status */
 240                 result = acpi_bus_get_status(link->device);
 241                 if (result) {
 242                         acpi_handle_err(handle, "Unable to read status\n");
 243                         goto end;
 244                 }
 245
 246                 if (!link->device->status.enabled) {
 247                         acpi_handle_debug(handle, "Link disabled\n");
 248                         return 0;
 249                 }
 250         }
 251
 252         /*
 253          * Query and parse _CRS to get the current IRQ assignment.
 254          */
 255
 256         status = acpi_walk_resources(handle, METHOD_NAME__CRS,
 257                                      acpi_pci_link_check_current, &irq);
 258         if (ACPI_FAILURE(status)) {
 259                 acpi_evaluation_failure_warn(handle, "_CRS", status);
 260                 result = -ENODEV;
 261                 goto end;
 262         }
 263
 264         if (acpi_strict && !irq) {
 265                 acpi_handle_err(handle, "_CRS returned 0\n");
 266                 result = -ENODEV;
 267         }
 268
 269         link->irq.active = irq;
 270
 271         acpi_handle_debug(handle, "Link at IRQ %d \n", link->irq.active);
 272
 273       end:
 274         return result;
 275 }
 276
 277 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 278 {
 279         struct {
 280                 struct acpi_resource res;
 281                 struct acpi_resource end;
 282         } *resource;
 283         struct acpi_buffer buffer = { 0, NULL };
 284         acpi_handle handle = link->device->handle;
 285         acpi_status status;
 286         int result;
 287
 288         if (!irq)
 289                 return -EINVAL;
 290
 291         resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
 292         if (!resource)
 293                 return -ENOMEM;
 294
 295         buffer.length = sizeof(*resource) + 1;
 296         buffer.pointer = resource;
 297
 298         switch (link->irq.resource_type) {
 299         case ACPI_RESOURCE_TYPE_IRQ:
 300                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 301                 resource->res.length = sizeof(struct acpi_resource);
 302                 resource->res.data.irq.triggering = link->irq.triggering;
 303                 resource->res.data.irq.polarity =
 304                     link->irq.polarity;
 305                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 306                         resource->res.data.irq.shareable =
 307                             ACPI_EXCLUSIVE;
 308                 else
 309                         resource->res.data.irq.shareable = ACPI_SHARED;
 310                 resource->res.data.irq.interrupt_count = 1;
 311                 resource->res.data.irq.interrupts[0] = irq;
 312                 break;
 313
 314         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 315                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 316                 resource->res.length = sizeof(struct acpi_resource);
 317                 resource->res.data.extended_irq.producer_consumer =
 318                     ACPI_CONSUMER;
 319                 resource->res.data.extended_irq.triggering =
 320                     link->irq.triggering;
 321                 resource->res.data.extended_irq.polarity =
 322                     link->irq.polarity;
 323                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 324                         resource->res.data.extended_irq.shareable =
 325                             ACPI_EXCLUSIVE;
 326                 else
 327                         resource->res.data.extended_irq.shareable = ACPI_SHARED;
 328                 resource->res.data.extended_irq.interrupt_count = 1;
 329                 resource->res.data.extended_irq.interrupts[0] = irq;
 330                 /* ignore resource_source, it's optional */
 331                 break;
 332         default:
 333                 acpi_handle_err(handle, "Invalid resource type %d\n",
 334                                 link->irq.resource_type);
 335                 result = -EINVAL;
 336                 goto end;
 337
 338         }
 339         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 340         resource->end.length = sizeof(struct acpi_resource);
 341
 342         /* Attempt to set the resource */
 343         status = acpi_set_current_resources(link->device->handle, &buffer);
 344
 345         /* check for total failure */
 346         if (ACPI_FAILURE(status)) {
 347                 acpi_evaluation_failure_warn(handle, "_SRS", status);
 348                 result = -ENODEV;
 349                 goto end;
 350         }
 351
 352         /* Query _STA, set device->status */
 353         result = acpi_bus_get_status(link->device);
 354         if (result) {
 355                 acpi_handle_err(handle, "Unable to read status\n");
 356                 goto end;
 357         }
 358         if (!link->device->status.enabled)
 359                 acpi_handle_warn(handle, "Disabled and referenced, BIOS bug\n");
 360
 361         /* Query _CRS, set link->irq.active */
 362         result = acpi_pci_link_get_current(link);
 363         if (result) {
 364                 goto end;
 365         }
 366
 367         /*
 368          * Is current setting not what we set?
 369          * set link->irq.active
 370          */
 371         if (link->irq.active != irq) {
 372                 /*
 373                  * policy: when _CRS doesn't return what we just _SRS
 374                  * assume _SRS worked and override _CRS value.
 375                  */
 376                 acpi_handle_warn(handle, "BIOS reported IRQ %d, using IRQ %d\n",
 377                                  link->irq.active, irq);
 378                 link->irq.active = irq;
 379         }
 380
 381         acpi_handle_debug(handle, "Set IRQ %d\n", link->irq.active);
 382
 383       end:
 384         kfree(resource);
 385         return result;
 386 }
 387
 388 /* --------------------------------------------------------------------------
 389                             PCI Link IRQ Management
 390    -------------------------------------------------------------------------- */
 391
 392 /*
 393  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 394  * Link Devices to move the PIRQs around to minimize sharing.
 395  *
 396  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 397  * that the BIOS has already set to active.  This is necessary because
 398  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 399  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 400  * even if acpi_irq_nobalance is set.
 401  *
 402  * A tables of penalties avoids directing PCI interrupts to well known
 403  * ISA IRQs. Boot params are available to over-ride the default table:
 404  *
 405  * List interrupts that are free for PCI use.
 406  * acpi_irq_pci=n[,m]
 407  *
 408  * List interrupts that should not be used for PCI:
 409  * acpi_irq_isa=n[,m]
 410  *
 411  * Note that PCI IRQ routers have a list of possible IRQs,
 412  * which may not include the IRQs this table says are available.
 413  *
 414  * Since this heuristic can't tell the difference between a link
 415  * that no device will attach to, vs. a link which may be shared
 416  * by multiple active devices -- it is not optimal.
 417  *
 418  * If interrupt performance is that important, get an IO-APIC system
 419  * with a pin dedicated to each device.  Or for that matter, an MSI
 420  * enabled system.
 421  */
 422
 423 #define ACPI_MAX_ISA_IRQS       16
 424
 425 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 426 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
 427 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 428 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 429 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 430
 431 static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
 432         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 433         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 434         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 435         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 436         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 437         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 438         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 439         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 440         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 441         0,                              /* IRQ9  PCI, often acpi */
 442         0,                              /* IRQ10 PCI */
 443         0,                              /* IRQ11 PCI */
 444         PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
 445         PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
 446         PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
 447         PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
 448         /* >IRQ15 */
 449 };
 450
 451 static int acpi_irq_pci_sharing_penalty(int irq)
 452 {
 453         struct acpi_pci_link *link;
 454         int penalty = 0;
 455         int i;
 456
 457         list_for_each_entry(link, &acpi_link_list, list) {
 458                 /*
 459                  * If a link is active, penalize its IRQ heavily
 460                  * so we try to choose a different IRQ.
 461                  */
 462                 if (link->irq.active && link->irq.active == irq)
 463                         penalty += PIRQ_PENALTY_PCI_USING;
 464
 465                 /*
 466                  * penalize the IRQs PCI might use, but not as severely.
 467                  */
 468                 for (i = 0; i < link->irq.possible_count; i++)
 469                         if (link->irq.possible[i] == irq)
 470                                 penalty += PIRQ_PENALTY_PCI_POSSIBLE /
 471                                         link->irq.possible_count;
 472         }
 473
 474         return penalty;
 475 }
 476
 477 static int acpi_irq_get_penalty(int irq)
 478 {
 479         int penalty = 0;
 480
 481         if (irq == sci_irq)
 482                 penalty += sci_penalty;
 483
 484         if (irq < ACPI_MAX_ISA_IRQS)
 485                 return penalty + acpi_isa_irq_penalty[irq];
 486
 487         return penalty + acpi_irq_pci_sharing_penalty(irq);
 488 }
 489
 490 int __init acpi_irq_penalty_init(void)
 491 {
 492         struct acpi_pci_link *link;
 493         int i;
 494
 495         /*
 496          * Update penalties to facilitate IRQ balancing.
 497          */
 498         list_for_each_entry(link, &acpi_link_list, list) {
 499
 500                 /*
 501                  * reflect the possible and active irqs in the penalty table --
 502                  * useful for breaking ties.
 503                  */
 504                 if (link->irq.possible_count) {
 505                         int penalty =
 506                             PIRQ_PENALTY_PCI_POSSIBLE /
 507                             link->irq.possible_count;
 508
 509                         for (i = 0; i < link->irq.possible_count; i++) {
 510                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
 511                                         acpi_isa_irq_penalty[link->irq.
 512                                                          possible[i]] +=
 513                                             penalty;
 514                         }
 515
 516                 } else if (link->irq.active &&
 517                                 (link->irq.active < ACPI_MAX_ISA_IRQS)) {
 518                         acpi_isa_irq_penalty[link->irq.active] +=
 519                             PIRQ_PENALTY_PCI_POSSIBLE;
 520                 }
 521         }
 522
 523         return 0;
 524 }
 525
 526 static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 527
 528 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 529 {
 530         acpi_handle handle = link->device->handle;
 531         int irq;
 532         int i;
 533
 534         if (link->irq.initialized) {
 535                 if (link->refcnt == 0)
 536                         /* This means the link is disabled but initialized */
 537                         acpi_pci_link_set(link, link->irq.active);
 538                 return 0;
 539         }
 540
 541         /*
 542          * search for active IRQ in list of possible IRQs.
 543          */
 544         for (i = 0; i < link->irq.possible_count; ++i) {
 545                 if (link->irq.active == link->irq.possible[i])
 546                         break;
 547         }
 548         /*
 549          * forget active IRQ that is not in possible list
 550          */
 551         if (i == link->irq.possible_count) {
 552                 if (acpi_strict)
 553                         acpi_handle_warn(handle, "_CRS %d not found in _PRS\n",
 554                                          link->irq.active);
 555                 link->irq.active = 0;
 556         }
 557
 558         /*
 559          * if active found, use it; else pick entry from end of possible list.
 560          */
 561         if (link->irq.active)
 562                 irq = link->irq.active;
 563         else
 564                 irq = link->irq.possible[link->irq.possible_count - 1];
 565
 566         if (acpi_irq_balance || !link->irq.active) {
 567                 /*
 568                  * Select the best IRQ.  This is done in reverse to promote
 569                  * the use of IRQs 9, 10, 11, and >15.
 570                  */
 571                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 572                         if (acpi_irq_get_penalty(irq) >
 573                             acpi_irq_get_penalty(link->irq.possible[i]))
 574                                 irq = link->irq.possible[i];
 575                 }
 576         }
 577         if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
 578                 acpi_handle_err(handle,
 579                                 "No IRQ available. Try pci=noacpi or acpi=off\n");
 580                 return -ENODEV;
 581         }
 582
 583         /* Attempt to enable the link device at this IRQ. */
 584         if (acpi_pci_link_set(link, irq)) {
 585                 acpi_handle_err(handle,
 586                                 "Unable to set IRQ. Try pci=noacpi or acpi=off\n");
 587                 return -ENODEV;
 588         } else {
 589                 if (link->irq.active < ACPI_MAX_ISA_IRQS)
 590                         acpi_isa_irq_penalty[link->irq.active] +=
 591                                 PIRQ_PENALTY_PCI_USING;
 592
 593                 acpi_handle_info(handle, "Enabled at IRQ %d\n",
 594                                  link->irq.active);
 595         }
 596
 597         link->irq.initialized = 1;
 598         return 0;
 599 }
 600
 601 /*
 602  * acpi_pci_link_allocate_irq
 603  * success: return IRQ >= 0
 604  * failure: return -1
 605  */
 606 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 607                                int *polarity, char **name)
 608 {
 609         struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 610         struct acpi_pci_link *link;
 611
 612         if (!device) {
 613                 acpi_handle_err(handle, "Invalid link device\n");
 614                 return -1;
 615         }
 616
 617         link = acpi_driver_data(device);
 618         if (!link) {
 619                 acpi_handle_err(handle, "Invalid link context\n");
 620                 return -1;
 621         }
 622
 623         /* TBD: Support multiple index (IRQ) entries per Link Device */
 624         if (index) {
 625                 acpi_handle_err(handle, "Invalid index %d\n", index);
 626                 return -1;
 627         }
 628
 629         mutex_lock(&acpi_link_lock);
 630         if (acpi_pci_link_allocate(link)) {
 631                 mutex_unlock(&acpi_link_lock);
 632                 return -1;
 633         }
 634
 635         if (!link->irq.active) {
 636                 mutex_unlock(&acpi_link_lock);
 637                 acpi_handle_err(handle, "Link active IRQ is 0!\n");
 638                 return -1;
 639         }
 640         link->refcnt++;
 641         mutex_unlock(&acpi_link_lock);
 642
 643         if (triggering)
 644                 *triggering = link->irq.triggering;
 645         if (polarity)
 646                 *polarity = link->irq.polarity;
 647         if (name)
 648                 *name = acpi_device_bid(link->device);
 649         acpi_handle_debug(handle, "Link is referenced\n");
 650         return link->irq.active;
 651 }
 652
 653 /*
 654  * We don't change link's irq information here.  After it is reenabled, we
 655  * continue use the info
 656  */
 657 int acpi_pci_link_free_irq(acpi_handle handle)
 658 {
 659         struct acpi_device *device = acpi_fetch_acpi_dev(handle);
 660         struct acpi_pci_link *link;
 661
 662         if (!device) {
 663                 acpi_handle_err(handle, "Invalid link device\n");
 664                 return -1;
 665         }
 666
 667         link = acpi_driver_data(device);
 668         if (!link) {
 669                 acpi_handle_err(handle, "Invalid link context\n");
 670                 return -1;
 671         }
 672
 673         mutex_lock(&acpi_link_lock);
 674         if (!link->irq.initialized) {
 675                 mutex_unlock(&acpi_link_lock);
 676                 acpi_handle_err(handle, "Link isn't initialized\n");
 677                 return -1;
 678         }
 679 #ifdef  FUTURE_USE
 680         /*
 681          * The Link reference count allows us to _DISable an unused link
 682          * and suspend time, and set it again  on resume.
 683          * However, 2.6.12 still has irq_router.resume
 684          * which blindly restores the link state.
 685          * So we disable the reference count method
 686          * to prevent duplicate acpi_pci_link_set()
 687          * which would harm some systems
 688          */
 689         link->refcnt--;
 690 #endif
 691         acpi_handle_debug(handle, "Link is dereferenced\n");
 692
 693         if (link->refcnt == 0)
 694                 acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 695
 696         mutex_unlock(&acpi_link_lock);
 697         return link->irq.active;
 698 }
 699
 700 /* --------------------------------------------------------------------------
 701                                  Driver Interface
 702    -------------------------------------------------------------------------- */
 703
 704 static int acpi_pci_link_add(struct acpi_device *device,
 705                              const struct acpi_device_id *not_used)
 706 {
 707         acpi_handle handle = device->handle;
 708         struct acpi_pci_link *link;
 709         int result;
 710         int i;
 711
 712         link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 713         if (!link)
 714                 return -ENOMEM;
 715
 716         link->device = device;
 717         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 718         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 719         device->driver_data = link;
 720
 721         mutex_lock(&acpi_link_lock);
 722         result = acpi_pci_link_get_possible(link);
 723         if (result)
 724                 goto end;
 725
 726         /* query and set link->irq.active */
 727         acpi_pci_link_get_current(link);
 728
 729         pr_info("Interrupt link %s configured for IRQ %d\n",
 730                 acpi_device_bid(device), link->irq.active);
 731
 732         for (i = 0; i < link->irq.possible_count; i++) {
 733                 if (link->irq.active != link->irq.possible[i])
 734                         acpi_handle_debug(handle, "Possible IRQ %d\n",
 735                                           link->irq.possible[i]);
 736         }
 737
 738         if (!link->device->status.enabled)
 739                 pr_info("Interrupt link %s disabled\n", acpi_device_bid(device));
 740
 741         list_add_tail(&link->list, &acpi_link_list);
 742
 743       end:
 744         /* disable all links -- to be activated on use */
 745         acpi_evaluate_object(handle, "_DIS", NULL, NULL);
 746         mutex_unlock(&acpi_link_lock);
 747
 748         if (result)
 749                 kfree(link);
 750
 751         return result < 0 ? result : 1;
 752 }
 753
 754 static int acpi_pci_link_resume(struct acpi_pci_link *link)
 755 {
 756         if (link->refcnt && link->irq.active && link->irq.initialized)
 757                 return (acpi_pci_link_set(link, link->irq.active));
 758
 759         return 0;
 760 }
 761
 762 static void irqrouter_resume(void)
 763 {
 764         struct acpi_pci_link *link;
 765
 766         list_for_each_entry(link, &acpi_link_list, list) {
 767                 acpi_pci_link_resume(link);
 768         }
 769 }
 770
 771 static void acpi_pci_link_remove(struct acpi_device *device)
 772 {
 773         struct acpi_pci_link *link;
 774
 775         link = acpi_driver_data(device);
 776
 777         mutex_lock(&acpi_link_lock);
 778         list_del(&link->list);
 779         mutex_unlock(&acpi_link_lock);
 780
 781         kfree(link);
 782 }
 783
 784 /*
 785  * modify acpi_isa_irq_penalty[] from cmdline
 786  */
 787 static int __init acpi_irq_penalty_update(char *str, int used)
 788 {
 789         int i;
 790
 791         for (i = 0; i < 16; i++) {
 792                 int retval;
 793                 int irq;
 794                 int new_penalty;
 795
 796                 retval = get_option(&str, &irq);
 797
 798                 if (!retval)
 799                         break;  /* no number found */
 800
 801                 /* see if this is a ISA IRQ */
 802                 if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
 803                         continue;
 804
 805                 if (used)
 806                         new_penalty = acpi_isa_irq_penalty[irq] +
 807                                         PIRQ_PENALTY_ISA_USED;
 808                 else
 809                         new_penalty = 0;
 810
 811                 acpi_isa_irq_penalty[irq] = new_penalty;
 812                 if (retval != 2)        /* no next number */
 813                         break;
 814         }
 815         return 1;
 816 }
 817
 818 /*
 819  * We'd like PNP to call this routine for the
 820  * single ISA_USED value for each legacy device.
 821  * But instead it calls us with each POSSIBLE setting.
 822  * There is no ISA_POSSIBLE weight, so we simply use
 823  * the (small) PCI_USING penalty.
 824  */
 825 void acpi_penalize_isa_irq(int irq, int active)
 826 {
 827         if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
 828                 acpi_isa_irq_penalty[irq] +=
 829                   (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
 830 }
 831
 832 bool acpi_isa_irq_available(int irq)
 833 {
 834         return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
 835                     acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
 836 }
 837
 838 void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
 839 {
 840         sci_irq = irq;
 841
 842         if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
 843             polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
 844                 sci_penalty = PIRQ_PENALTY_PCI_USING;
 845         else
 846                 sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
 847 }
 848
 849 /*
 850  * Over-ride default table to reserve additional IRQs for use by ISA
 851  * e.g. acpi_irq_isa=5
 852  * Useful for telling ACPI how not to interfere with your ISA sound card.
 853  */
 854 static int __init acpi_irq_isa(char *str)
 855 {
 856         return acpi_irq_penalty_update(str, 1);
 857 }
 858
 859 __setup("acpi_irq_isa=", acpi_irq_isa);
 860
 861 /*
 862  * Over-ride default table to free additional IRQs for use by PCI
 863  * e.g. acpi_irq_pci=7,15
 864  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 865  */
 866 static int __init acpi_irq_pci(char *str)
 867 {
 868         return acpi_irq_penalty_update(str, 0);
 869 }
 870
 871 __setup("acpi_irq_pci=", acpi_irq_pci);
 872
 873 static int __init acpi_irq_nobalance_set(char *str)
 874 {
 875         acpi_irq_balance = 0;
 876         return 1;
 877 }
 878
 879 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 880
 881 static int __init acpi_irq_balance_set(char *str)
 882 {
 883         acpi_irq_balance = 1;
 884         return 1;
 885 }
 886
 887 __setup("acpi_irq_balance", acpi_irq_balance_set);
 888
 889 static struct syscore_ops irqrouter_syscore_ops = {
 890         .resume = irqrouter_resume,
 891 };
 892
 893 void __init acpi_pci_link_init(void)
 894 {
 895         if (acpi_noirq)
 896                 return;
 897
 898         if (acpi_irq_balance == -1) {
 899                 /* no command line switch: enable balancing in IOAPIC mode */
 900                 if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 901                         acpi_irq_balance = 1;
 902                 else
 903                         acpi_irq_balance = 0;
 904         }
 905         register_syscore_ops(&irqrouter_syscore_ops);
 906         acpi_scan_add_handler(&pci_link_handler);
 907 }