LXR linux/drivers/acpi/pci

   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
  47ACPI_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
  54static int acpi_pci_link_add(struct acpi_device *device,
  55                             const struct acpi_device_id *not_used);
  56static void acpi_pci_link_remove(struct acpi_device *device);
  57
  58static const struct acpi_device_id link_device_ids[] = {
  59        {"PNP0C0F", 0},
  60        {"", 0},
  61};
  62
  63static 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 */
  73struct 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
  84struct 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
  91static LIST_HEAD(acpi_link_list);
  92static 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 */
 101static 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
 171static 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
 189static 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 */
 246static 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
 294static 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
 454static 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
 474int __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
 510static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 511
 512static 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 */
 584int 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 */
 639int 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
 690static 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
 748static 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
 756static 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
 765static 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 */
 781static 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 */
 818void 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 */
 833static 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 */
 845static 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
 852static 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
 860static 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
 868static struct syscore_ops irqrouter_syscore_ops = {
 869        .resume = irqrouter_resume,
 870};
 871
 872void __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}
 887