LXR linux/drivers/acpi/pci

   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
  36static int acpi_pci_link_add(struct acpi_device *device,
  37                             const struct acpi_device_id *not_used);
  38static void acpi_pci_link_remove(struct acpi_device *device);
  39
  40static const struct acpi_device_id link_device_ids[] = {
  41        {"PNP0C0F", 0},
  42        {"", 0},
  43};
  44
  45static 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 */
  55struct 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
  66struct 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
  73static LIST_HEAD(acpi_link_list);
  74static DEFINE_MUTEX(acpi_link_lock);
  75static 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 */
  84static 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 || !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 || !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
 155static 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
 173static 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 || !p->interrupt_count) {
 186                                /*
 187                                 * IRQ descriptors may have no IRQ# bits set,
 188                                 * particularly those 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 || !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 */
 228static 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
 277static 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
 431static 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
 451static 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
 477static 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
 490int __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
 526static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 527
 528static 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 */
 606int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 607                               int *polarity, char **name)
 608{
 609        int result;
 610        struct acpi_device *device;
 611        struct acpi_pci_link *link;
 612
 613        result = acpi_bus_get_device(handle, &device);
 614        if (result) {
 615                acpi_handle_err(handle, "Invalid link device\n");
 616                return -1;
 617        }
 618
 619        link = acpi_driver_data(device);
 620        if (!link) {
 621                acpi_handle_err(handle, "Invalid link context\n");
 622                return -1;
 623        }
 624
 625        /* TBD: Support multiple index (IRQ) entries per Link Device */
 626        if (index) {
 627                acpi_handle_err(handle, "Invalid index %d\n", index);
 628                return -1;
 629        }
 630
 631        mutex_lock(&acpi_link_lock);
 632        if (acpi_pci_link_allocate(link)) {
 633                mutex_unlock(&acpi_link_lock);
 634                return -1;
 635        }
 636
 637        if (!link->irq.active) {
 638                mutex_unlock(&acpi_link_lock);
 639                acpi_handle_err(handle, "Link active IRQ is 0!\n");
 640                return -1;
 641        }
 642        link->refcnt++;
 643        mutex_unlock(&acpi_link_lock);
 644
 645        if (triggering)
 646                *triggering = link->irq.triggering;
 647        if (polarity)
 648                *polarity = link->irq.polarity;
 649        if (name)
 650                *name = acpi_device_bid(link->device);
 651        acpi_handle_debug(handle, "Link is referenced\n");
 652        return link->irq.active;
 653}
 654
 655/*
 656 * We don't change link's irq information here.  After it is reenabled, we
 657 * continue use the info
 658 */
 659int acpi_pci_link_free_irq(acpi_handle handle)
 660{
 661        struct acpi_device *device;
 662        struct acpi_pci_link *link;
 663        acpi_status result;
 664
 665        result = acpi_bus_get_device(handle, &device);
 666        if (result) {
 667                acpi_handle_err(handle, "Invalid link device\n");
 668                return -1;
 669        }
 670
 671        link = acpi_driver_data(device);
 672        if (!link) {
 673                acpi_handle_err(handle, "Invalid link context\n");
 674                return -1;
 675        }
 676
 677        mutex_lock(&acpi_link_lock);
 678        if (!link->irq.initialized) {
 679                mutex_unlock(&acpi_link_lock);
 680                acpi_handle_err(handle, "Link isn't initialized\n");
 681                return -1;
 682        }
 683#ifdef  FUTURE_USE
 684        /*
 685         * The Link reference count allows us to _DISable an unused link
 686         * and suspend time, and set it again  on resume.
 687         * However, 2.6.12 still has irq_router.resume
 688         * which blindly restores the link state.
 689         * So we disable the reference count method
 690         * to prevent duplicate acpi_pci_link_set()
 691         * which would harm some systems
 692         */
 693        link->refcnt--;
 694#endif
 695        acpi_handle_debug(handle, "Link is dereferenced\n");
 696
 697        if (link->refcnt == 0)
 698                acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 699
 700        mutex_unlock(&acpi_link_lock);
 701        return link->irq.active;
 702}
 703
 704/* --------------------------------------------------------------------------
 705                                 Driver Interface
 706   -------------------------------------------------------------------------- */
 707
 708static int acpi_pci_link_add(struct acpi_device *device,
 709                             const struct acpi_device_id *not_used)
 710{
 711        acpi_handle handle = device->handle;
 712        struct acpi_pci_link *link;
 713        int result;
 714        int i;
 715
 716        link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 717        if (!link)
 718                return -ENOMEM;
 719
 720        link->device = device;
 721        strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 722        strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 723        device->driver_data = link;
 724
 725        mutex_lock(&acpi_link_lock);
 726        result = acpi_pci_link_get_possible(link);
 727        if (result)
 728                goto end;
 729
 730        /* query and set link->irq.active */
 731        acpi_pci_link_get_current(link);
 732
 733        pr_info("Interrupt link %s configured for IRQ %d\n",
 734                acpi_device_bid(device), link->irq.active);
 735
 736        for (i = 0; i < link->irq.possible_count; i++) {
 737                if (link->irq.active != link->irq.possible[i])
 738                        acpi_handle_debug(handle, "Possible IRQ %d\n",
 739                                          link->irq.possible[i]);
 740        }
 741
 742        if (!link->device->status.enabled)
 743                pr_info("Interrupt link %s disabled\n", acpi_device_bid(device));
 744
 745        list_add_tail(&link->list, &acpi_link_list);
 746
 747      end:
 748        /* disable all links -- to be activated on use */
 749        acpi_evaluate_object(handle, "_DIS", NULL, NULL);
 750        mutex_unlock(&acpi_link_lock);
 751
 752        if (result)
 753                kfree(link);
 754
 755        return result < 0 ? result : 1;
 756}
 757
 758static int acpi_pci_link_resume(struct acpi_pci_link *link)
 759{
 760        if (link->refcnt && link->irq.active && link->irq.initialized)
 761                return (acpi_pci_link_set(link, link->irq.active));
 762
 763        return 0;
 764}
 765
 766static void irqrouter_resume(void)
 767{
 768        struct acpi_pci_link *link;
 769
 770        list_for_each_entry(link, &acpi_link_list, list) {
 771                acpi_pci_link_resume(link);
 772        }
 773}
 774
 775static void acpi_pci_link_remove(struct acpi_device *device)
 776{
 777        struct acpi_pci_link *link;
 778
 779        link = acpi_driver_data(device);
 780
 781        mutex_lock(&acpi_link_lock);
 782        list_del(&link->list);
 783        mutex_unlock(&acpi_link_lock);
 784
 785        kfree(link);
 786}
 787
 788/*
 789 * modify acpi_isa_irq_penalty[] from cmdline
 790 */
 791static int __init acpi_irq_penalty_update(char *str, int used)
 792{
 793        int i;
 794
 795        for (i = 0; i < 16; i++) {
 796                int retval;
 797                int irq;
 798                int new_penalty;
 799
 800                retval = get_option(&str, &irq);
 801
 802                if (!retval)
 803                        break;  /* no number found */
 804
 805                /* see if this is a ISA IRQ */
 806                if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
 807                        continue;
 808
 809                if (used)
 810                        new_penalty = acpi_isa_irq_penalty[irq] +
 811                                        PIRQ_PENALTY_ISA_USED;
 812                else
 813                        new_penalty = 0;
 814
 815                acpi_isa_irq_penalty[irq] = new_penalty;
 816                if (retval != 2)        /* no next number */
 817                        break;
 818        }
 819        return 1;
 820}
 821
 822/*
 823 * We'd like PNP to call this routine for the
 824 * single ISA_USED value for each legacy device.
 825 * But instead it calls us with each POSSIBLE setting.
 826 * There is no ISA_POSSIBLE weight, so we simply use
 827 * the (small) PCI_USING penalty.
 828 */
 829void acpi_penalize_isa_irq(int irq, int active)
 830{
 831        if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
 832                acpi_isa_irq_penalty[irq] +=
 833                  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
 834}
 835
 836bool acpi_isa_irq_available(int irq)
 837{
 838        return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
 839                    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
 840}
 841
 842void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
 843{
 844        sci_irq = irq;
 845
 846        if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
 847            polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
 848                sci_penalty = PIRQ_PENALTY_PCI_USING;
 849        else
 850                sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
 851}
 852
 853/*
 854 * Over-ride default table to reserve additional IRQs for use by ISA
 855 * e.g. acpi_irq_isa=5
 856 * Useful for telling ACPI how not to interfere with your ISA sound card.
 857 */
 858static int __init acpi_irq_isa(char *str)
 859{
 860        return acpi_irq_penalty_update(str, 1);
 861}
 862
 863__setup("acpi_irq_isa=", acpi_irq_isa);
 864
 865/*
 866 * Over-ride default table to free additional IRQs for use by PCI
 867 * e.g. acpi_irq_pci=7,15
 868 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 869 */
 870static int __init acpi_irq_pci(char *str)
 871{
 872        return acpi_irq_penalty_update(str, 0);
 873}
 874
 875__setup("acpi_irq_pci=", acpi_irq_pci);
 876
 877static int __init acpi_irq_nobalance_set(char *str)
 878{
 879        acpi_irq_balance = 0;
 880        return 1;
 881}
 882
 883__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 884
 885static int __init acpi_irq_balance_set(char *str)
 886{
 887        acpi_irq_balance = 1;
 888        return 1;
 889}
 890
 891__setup("acpi_irq_balance", acpi_irq_balance_set);
 892
 893static struct syscore_ops irqrouter_syscore_ops = {
 894        .resume = irqrouter_resume,
 895};
 896
 897void __init acpi_pci_link_init(void)
 898{
 899        if (acpi_noirq)
 900                return;
 901
 902        if (acpi_irq_balance == -1) {
 903                /* no command line switch: enable balancing in IOAPIC mode */
 904                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 905                        acpi_irq_balance = 1;
 906                else
 907                        acpi_irq_balance = 0;
 908        }
 909        register_syscore_ops(&irqrouter_syscore_ops);
 910        acpi_scan_add_handler(&pci_link_handler);
 911}
 912