linux/drivers/acpi/pci_link.c
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   1/*
   2 *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
   3 *
   4 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   5 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   6 *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
   7 *
   8 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   9 *
  10 *  This program is free software; you can redistribute it and/or modify
  11 *  it under the terms of the GNU General Public License as published by
  12 *  the Free Software Foundation; either version 2 of the License, or (at
  13 *  your option) any later version.
  14 *
  15 *  This program is distributed in the hope that it will be useful, but
  16 *  WITHOUT ANY WARRANTY; without even the implied warranty of
  17 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18 *  General Public License for more details.
  19 *
  20 *  You should have received a copy of the GNU General Public License along
  21 *  with this program; if not, write to the Free Software Foundation, Inc.,
  22 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  23 *
  24 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  25 *
  26 * TBD: 
  27 *      1. Support more than one IRQ resource entry per link device (index).
  28 *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
  29 *         for IRQ management (e.g. start()->_SRS).
  30 */
  31
  32#include <linux/syscore_ops.h>
  33#include <linux/kernel.h>
  34#include <linux/module.h>
  35#include <linux/init.h>
  36#include <linux/types.h>
  37#include <linux/spinlock.h>
  38#include <linux/pm.h>
  39#include <linux/pci.h>
  40#include <linux/mutex.h>
  41#include <linux/slab.h>
  42
  43#include <acpi/acpi_bus.h>
  44#include <acpi/acpi_drivers.h>
  45
  46#define PREFIX "ACPI: "
  47
  48#define _COMPONENT                      ACPI_PCI_COMPONENT
  49ACPI_MODULE_NAME("pci_link");
  50#define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  51#define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
  52#define ACPI_PCI_LINK_FILE_INFO         "info"
  53#define ACPI_PCI_LINK_FILE_STATUS       "state"
  54#define ACPI_PCI_LINK_MAX_POSSIBLE      16
  55
  56static int acpi_pci_link_add(struct acpi_device *device,
  57                             const struct acpi_device_id *not_used);
  58static void acpi_pci_link_remove(struct acpi_device *device);
  59
  60static const struct acpi_device_id link_device_ids[] = {
  61        {"PNP0C0F", 0},
  62        {"", 0},
  63};
  64
  65static struct acpi_scan_handler pci_link_handler = {
  66        .ids = link_device_ids,
  67        .attach = acpi_pci_link_add,
  68        .detach = acpi_pci_link_remove,
  69};
  70
  71/*
  72 * If a link is initialized, we never change its active and initialized
  73 * later even the link is disable. Instead, we just repick the active irq
  74 */
  75struct acpi_pci_link_irq {
  76        u8 active;              /* Current IRQ */
  77        u8 triggering;          /* All IRQs */
  78        u8 polarity;            /* All IRQs */
  79        u8 resource_type;
  80        u8 possible_count;
  81        u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  82        u8 initialized:1;
  83        u8 reserved:7;
  84};
  85
  86struct acpi_pci_link {
  87        struct list_head                list;
  88        struct acpi_device              *device;
  89        struct acpi_pci_link_irq        irq;
  90        int                             refcnt;
  91};
  92
  93static LIST_HEAD(acpi_link_list);
  94static DEFINE_MUTEX(acpi_link_lock);
  95
  96/* --------------------------------------------------------------------------
  97                            PCI Link Device Management
  98   -------------------------------------------------------------------------- */
  99
 100/*
 101 * set context (link) possible list from resource list
 102 */
 103static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
 104                                                void *context)
 105{
 106        struct acpi_pci_link *link = context;
 107        u32 i;
 108
 109        switch (resource->type) {
 110        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 111        case ACPI_RESOURCE_TYPE_END_TAG:
 112                return AE_OK;
 113        case ACPI_RESOURCE_TYPE_IRQ:
 114                {
 115                        struct acpi_resource_irq *p = &resource->data.irq;
 116                        if (!p || !p->interrupt_count) {
 117                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 118                                                  "Blank _PRS IRQ resource\n"));
 119                                return AE_OK;
 120                        }
 121                        for (i = 0;
 122                             (i < p->interrupt_count
 123                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 124                                if (!p->interrupts[i]) {
 125                                        printk(KERN_WARNING PREFIX
 126                                               "Invalid _PRS IRQ %d\n",
 127                                               p->interrupts[i]);
 128                                        continue;
 129                                }
 130                                link->irq.possible[i] = p->interrupts[i];
 131                                link->irq.possible_count++;
 132                        }
 133                        link->irq.triggering = p->triggering;
 134                        link->irq.polarity = p->polarity;
 135                        link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 136                        break;
 137                }
 138        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 139                {
 140                        struct acpi_resource_extended_irq *p =
 141                            &resource->data.extended_irq;
 142                        if (!p || !p->interrupt_count) {
 143                                printk(KERN_WARNING PREFIX
 144                                              "Blank _PRS EXT IRQ resource\n");
 145                                return AE_OK;
 146                        }
 147                        for (i = 0;
 148                             (i < p->interrupt_count
 149                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 150                                if (!p->interrupts[i]) {
 151                                        printk(KERN_WARNING PREFIX
 152                                               "Invalid _PRS IRQ %d\n",
 153                                               p->interrupts[i]);
 154                                        continue;
 155                                }
 156                                link->irq.possible[i] = p->interrupts[i];
 157                                link->irq.possible_count++;
 158                        }
 159                        link->irq.triggering = p->triggering;
 160                        link->irq.polarity = p->polarity;
 161                        link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 162                        break;
 163                }
 164        default:
 165                printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
 166                       resource->type);
 167                return AE_OK;
 168        }
 169
 170        return AE_CTRL_TERMINATE;
 171}
 172
 173static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 174{
 175        acpi_status status;
 176
 177        status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
 178                                     acpi_pci_link_check_possible, link);
 179        if (ACPI_FAILURE(status)) {
 180                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
 181                return -ENODEV;
 182        }
 183
 184        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 185                          "Found %d possible IRQs\n",
 186                          link->irq.possible_count));
 187
 188        return 0;
 189}
 190
 191static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 192                                               void *context)
 193{
 194        int *irq = context;
 195
 196        switch (resource->type) {
 197        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 198        case ACPI_RESOURCE_TYPE_END_TAG:
 199                return AE_OK;
 200        case ACPI_RESOURCE_TYPE_IRQ:
 201                {
 202                        struct acpi_resource_irq *p = &resource->data.irq;
 203                        if (!p || !p->interrupt_count) {
 204                                /*
 205                                 * IRQ descriptors may have no IRQ# bits set,
 206                                 * particularly those those w/ _STA disabled
 207                                 */
 208                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 209                                                  "Blank _CRS IRQ resource\n"));
 210                                return AE_OK;
 211                        }
 212                        *irq = p->interrupts[0];
 213                        break;
 214                }
 215        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 216                {
 217                        struct acpi_resource_extended_irq *p =
 218                            &resource->data.extended_irq;
 219                        if (!p || !p->interrupt_count) {
 220                                /*
 221                                 * extended IRQ descriptors must
 222                                 * return at least 1 IRQ
 223                                 */
 224                                printk(KERN_WARNING PREFIX
 225                                              "Blank _CRS EXT IRQ resource\n");
 226                                return AE_OK;
 227                        }
 228                        *irq = p->interrupts[0];
 229                        break;
 230                }
 231                break;
 232        default:
 233                printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
 234                       resource->type);
 235                return AE_OK;
 236        }
 237
 238        return AE_CTRL_TERMINATE;
 239}
 240
 241/*
 242 * Run _CRS and set link->irq.active
 243 *
 244 * return value:
 245 * 0 - success
 246 * !0 - failure
 247 */
 248static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 249{
 250        int result = 0;
 251        acpi_status status;
 252        int irq = 0;
 253
 254        link->irq.active = 0;
 255
 256        /* in practice, status disabled is meaningless, ignore it */
 257        if (acpi_strict) {
 258                /* Query _STA, set link->device->status */
 259                result = acpi_bus_get_status(link->device);
 260                if (result) {
 261                        printk(KERN_ERR PREFIX "Unable to read status\n");
 262                        goto end;
 263                }
 264
 265                if (!link->device->status.enabled) {
 266                        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
 267                        return 0;
 268                }
 269        }
 270
 271        /* 
 272         * Query and parse _CRS to get the current IRQ assignment. 
 273         */
 274
 275        status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
 276                                     acpi_pci_link_check_current, &irq);
 277        if (ACPI_FAILURE(status)) {
 278                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
 279                result = -ENODEV;
 280                goto end;
 281        }
 282
 283        if (acpi_strict && !irq) {
 284                printk(KERN_ERR PREFIX "_CRS returned 0\n");
 285                result = -ENODEV;
 286        }
 287
 288        link->irq.active = irq;
 289
 290        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
 291
 292      end:
 293        return result;
 294}
 295
 296static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 297{
 298        int result;
 299        acpi_status status;
 300        struct {
 301                struct acpi_resource res;
 302                struct acpi_resource end;
 303        } *resource;
 304        struct acpi_buffer buffer = { 0, NULL };
 305
 306        if (!irq)
 307                return -EINVAL;
 308
 309        resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
 310        if (!resource)
 311                return -ENOMEM;
 312
 313        buffer.length = sizeof(*resource) + 1;
 314        buffer.pointer = resource;
 315
 316        switch (link->irq.resource_type) {
 317        case ACPI_RESOURCE_TYPE_IRQ:
 318                resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 319                resource->res.length = sizeof(struct acpi_resource);
 320                resource->res.data.irq.triggering = link->irq.triggering;
 321                resource->res.data.irq.polarity =
 322                    link->irq.polarity;
 323                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 324                        resource->res.data.irq.sharable =
 325                            ACPI_EXCLUSIVE;
 326                else
 327                        resource->res.data.irq.sharable = ACPI_SHARED;
 328                resource->res.data.irq.interrupt_count = 1;
 329                resource->res.data.irq.interrupts[0] = irq;
 330                break;
 331
 332        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 333                resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 334                resource->res.length = sizeof(struct acpi_resource);
 335                resource->res.data.extended_irq.producer_consumer =
 336                    ACPI_CONSUMER;
 337                resource->res.data.extended_irq.triggering =
 338                    link->irq.triggering;
 339                resource->res.data.extended_irq.polarity =
 340                    link->irq.polarity;
 341                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 342                        resource->res.data.irq.sharable =
 343                            ACPI_EXCLUSIVE;
 344                else
 345                        resource->res.data.irq.sharable = ACPI_SHARED;
 346                resource->res.data.extended_irq.interrupt_count = 1;
 347                resource->res.data.extended_irq.interrupts[0] = irq;
 348                /* ignore resource_source, it's optional */
 349                break;
 350        default:
 351                printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
 352                result = -EINVAL;
 353                goto end;
 354
 355        }
 356        resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 357
 358        /* Attempt to set the resource */
 359        status = acpi_set_current_resources(link->device->handle, &buffer);
 360
 361        /* check for total failure */
 362        if (ACPI_FAILURE(status)) {
 363                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
 364                result = -ENODEV;
 365                goto end;
 366        }
 367
 368        /* Query _STA, set device->status */
 369        result = acpi_bus_get_status(link->device);
 370        if (result) {
 371                printk(KERN_ERR PREFIX "Unable to read status\n");
 372                goto end;
 373        }
 374        if (!link->device->status.enabled) {
 375                printk(KERN_WARNING PREFIX
 376                              "%s [%s] disabled and referenced, BIOS bug\n",
 377                              acpi_device_name(link->device),
 378                              acpi_device_bid(link->device));
 379        }
 380
 381        /* Query _CRS, set link->irq.active */
 382        result = acpi_pci_link_get_current(link);
 383        if (result) {
 384                goto end;
 385        }
 386
 387        /*
 388         * Is current setting not what we set?
 389         * set link->irq.active
 390         */
 391        if (link->irq.active != irq) {
 392                /*
 393                 * policy: when _CRS doesn't return what we just _SRS
 394                 * assume _SRS worked and override _CRS value.
 395                 */
 396                printk(KERN_WARNING PREFIX
 397                              "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 398                              acpi_device_name(link->device),
 399                              acpi_device_bid(link->device), link->irq.active, irq);
 400                link->irq.active = irq;
 401        }
 402
 403        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 404
 405      end:
 406        kfree(resource);
 407        return result;
 408}
 409
 410/* --------------------------------------------------------------------------
 411                            PCI Link IRQ Management
 412   -------------------------------------------------------------------------- */
 413
 414/*
 415 * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 416 * Link Devices to move the PIRQs around to minimize sharing.
 417 * 
 418 * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 419 * that the BIOS has already set to active.  This is necessary because
 420 * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 421 * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 422 * even if acpi_irq_nobalance is set.
 423 *
 424 * A tables of penalties avoids directing PCI interrupts to well known
 425 * ISA IRQs. Boot params are available to over-ride the default table:
 426 *
 427 * List interrupts that are free for PCI use.
 428 * acpi_irq_pci=n[,m]
 429 *
 430 * List interrupts that should not be used for PCI:
 431 * acpi_irq_isa=n[,m]
 432 *
 433 * Note that PCI IRQ routers have a list of possible IRQs,
 434 * which may not include the IRQs this table says are available.
 435 * 
 436 * Since this heuristic can't tell the difference between a link
 437 * that no device will attach to, vs. a link which may be shared
 438 * by multiple active devices -- it is not optimal.
 439 *
 440 * If interrupt performance is that important, get an IO-APIC system
 441 * with a pin dedicated to each device.  Or for that matter, an MSI
 442 * enabled system.
 443 */
 444
 445#define ACPI_MAX_IRQS           256
 446#define ACPI_MAX_ISA_IRQ        16
 447
 448#define PIRQ_PENALTY_PCI_AVAILABLE      (0)
 449#define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 450#define PIRQ_PENALTY_PCI_USING          (16*16*16)
 451#define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 452#define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 453#define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 454
 455static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 456        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 457        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 458        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 459        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 460        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 461        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 462        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 463        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 464        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 465        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
 466        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
 467        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
 468        PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
 469        PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
 470        PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
 471        PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
 472        /* >IRQ15 */
 473};
 474
 475int __init acpi_irq_penalty_init(void)
 476{
 477        struct acpi_pci_link *link;
 478        int i;
 479
 480        /*
 481         * Update penalties to facilitate IRQ balancing.
 482         */
 483        list_for_each_entry(link, &acpi_link_list, list) {
 484
 485                /*
 486                 * reflect the possible and active irqs in the penalty table --
 487                 * useful for breaking ties.
 488                 */
 489                if (link->irq.possible_count) {
 490                        int penalty =
 491                            PIRQ_PENALTY_PCI_POSSIBLE /
 492                            link->irq.possible_count;
 493
 494                        for (i = 0; i < link->irq.possible_count; i++) {
 495                                if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
 496                                        acpi_irq_penalty[link->irq.
 497                                                         possible[i]] +=
 498                                            penalty;
 499                        }
 500
 501                } else if (link->irq.active) {
 502                        acpi_irq_penalty[link->irq.active] +=
 503                            PIRQ_PENALTY_PCI_POSSIBLE;
 504                }
 505        }
 506        /* Add a penalty for the SCI */
 507        acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
 508        return 0;
 509}
 510
 511static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 512
 513static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 514{
 515        int irq;
 516        int i;
 517
 518        if (link->irq.initialized) {
 519                if (link->refcnt == 0)
 520                        /* This means the link is disabled but initialized */
 521                        acpi_pci_link_set(link, link->irq.active);
 522                return 0;
 523        }
 524
 525        /*
 526         * search for active IRQ in list of possible IRQs.
 527         */
 528        for (i = 0; i < link->irq.possible_count; ++i) {
 529                if (link->irq.active == link->irq.possible[i])
 530                        break;
 531        }
 532        /*
 533         * forget active IRQ that is not in possible list
 534         */
 535        if (i == link->irq.possible_count) {
 536                if (acpi_strict)
 537                        printk(KERN_WARNING PREFIX "_CRS %d not found"
 538                                      " in _PRS\n", link->irq.active);
 539                link->irq.active = 0;
 540        }
 541
 542        /*
 543         * if active found, use it; else pick entry from end of possible list.
 544         */
 545        if (link->irq.active)
 546                irq = link->irq.active;
 547        else
 548                irq = link->irq.possible[link->irq.possible_count - 1];
 549
 550        if (acpi_irq_balance || !link->irq.active) {
 551                /*
 552                 * Select the best IRQ.  This is done in reverse to promote
 553                 * the use of IRQs 9, 10, 11, and >15.
 554                 */
 555                for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 556                        if (acpi_irq_penalty[irq] >
 557                            acpi_irq_penalty[link->irq.possible[i]])
 558                                irq = link->irq.possible[i];
 559                }
 560        }
 561
 562        /* Attempt to enable the link device at this IRQ. */
 563        if (acpi_pci_link_set(link, irq)) {
 564                printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
 565                            "Try pci=noacpi or acpi=off\n",
 566                            acpi_device_name(link->device),
 567                            acpi_device_bid(link->device));
 568                return -ENODEV;
 569        } else {
 570                acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 571                printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
 572                       acpi_device_name(link->device),
 573                       acpi_device_bid(link->device), link->irq.active);
 574        }
 575
 576        link->irq.initialized = 1;
 577        return 0;
 578}
 579
 580/*
 581 * acpi_pci_link_allocate_irq
 582 * success: return IRQ >= 0
 583 * failure: return -1
 584 */
 585int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 586                               int *polarity, char **name)
 587{
 588        int result;
 589        struct acpi_device *device;
 590        struct acpi_pci_link *link;
 591
 592        result = acpi_bus_get_device(handle, &device);
 593        if (result) {
 594                printk(KERN_ERR PREFIX "Invalid link device\n");
 595                return -1;
 596        }
 597
 598        link = acpi_driver_data(device);
 599        if (!link) {
 600                printk(KERN_ERR PREFIX "Invalid link context\n");
 601                return -1;
 602        }
 603
 604        /* TBD: Support multiple index (IRQ) entries per Link Device */
 605        if (index) {
 606                printk(KERN_ERR PREFIX "Invalid index %d\n", index);
 607                return -1;
 608        }
 609
 610        mutex_lock(&acpi_link_lock);
 611        if (acpi_pci_link_allocate(link)) {
 612                mutex_unlock(&acpi_link_lock);
 613                return -1;
 614        }
 615
 616        if (!link->irq.active) {
 617                mutex_unlock(&acpi_link_lock);
 618                printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
 619                return -1;
 620        }
 621        link->refcnt++;
 622        mutex_unlock(&acpi_link_lock);
 623
 624        if (triggering)
 625                *triggering = link->irq.triggering;
 626        if (polarity)
 627                *polarity = link->irq.polarity;
 628        if (name)
 629                *name = acpi_device_bid(link->device);
 630        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 631                          "Link %s is referenced\n",
 632                          acpi_device_bid(link->device)));
 633        return (link->irq.active);
 634}
 635
 636/*
 637 * We don't change link's irq information here.  After it is reenabled, we
 638 * continue use the info
 639 */
 640int acpi_pci_link_free_irq(acpi_handle handle)
 641{
 642        struct acpi_device *device;
 643        struct acpi_pci_link *link;
 644        acpi_status result;
 645
 646        result = acpi_bus_get_device(handle, &device);
 647        if (result) {
 648                printk(KERN_ERR PREFIX "Invalid link device\n");
 649                return -1;
 650        }
 651
 652        link = acpi_driver_data(device);
 653        if (!link) {
 654                printk(KERN_ERR PREFIX "Invalid link context\n");
 655                return -1;
 656        }
 657
 658        mutex_lock(&acpi_link_lock);
 659        if (!link->irq.initialized) {
 660                mutex_unlock(&acpi_link_lock);
 661                printk(KERN_ERR PREFIX "Link isn't initialized\n");
 662                return -1;
 663        }
 664#ifdef  FUTURE_USE
 665        /*
 666         * The Link reference count allows us to _DISable an unused link
 667         * and suspend time, and set it again  on resume.
 668         * However, 2.6.12 still has irq_router.resume
 669         * which blindly restores the link state.
 670         * So we disable the reference count method
 671         * to prevent duplicate acpi_pci_link_set()
 672         * which would harm some systems
 673         */
 674        link->refcnt--;
 675#endif
 676        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 677                          "Link %s is dereferenced\n",
 678                          acpi_device_bid(link->device)));
 679
 680        if (link->refcnt == 0)
 681                acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 682
 683        mutex_unlock(&acpi_link_lock);
 684        return (link->irq.active);
 685}
 686
 687/* --------------------------------------------------------------------------
 688                                 Driver Interface
 689   -------------------------------------------------------------------------- */
 690
 691static int acpi_pci_link_add(struct acpi_device *device,
 692                             const struct acpi_device_id *not_used)
 693{
 694        int result;
 695        struct acpi_pci_link *link;
 696        int i;
 697        int found = 0;
 698
 699        link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 700        if (!link)
 701                return -ENOMEM;
 702
 703        link->device = device;
 704        strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 705        strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 706        device->driver_data = link;
 707
 708        mutex_lock(&acpi_link_lock);
 709        result = acpi_pci_link_get_possible(link);
 710        if (result)
 711                goto end;
 712
 713        /* query and set link->irq.active */
 714        acpi_pci_link_get_current(link);
 715
 716        printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 717               acpi_device_bid(device));
 718        for (i = 0; i < link->irq.possible_count; i++) {
 719                if (link->irq.active == link->irq.possible[i]) {
 720                        printk(KERN_CONT " *%d", link->irq.possible[i]);
 721                        found = 1;
 722                } else
 723                        printk(KERN_CONT " %d", link->irq.possible[i]);
 724        }
 725
 726        printk(KERN_CONT ")");
 727
 728        if (!found)
 729                printk(KERN_CONT " *%d", link->irq.active);
 730
 731        if (!link->device->status.enabled)
 732                printk(KERN_CONT ", disabled.");
 733
 734        printk(KERN_CONT "\n");
 735
 736        list_add_tail(&link->list, &acpi_link_list);
 737
 738      end:
 739        /* disable all links -- to be activated on use */
 740        acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
 741        mutex_unlock(&acpi_link_lock);
 742
 743        if (result)
 744                kfree(link);
 745
 746        return result < 0 ? result : 1;
 747}
 748
 749static int acpi_pci_link_resume(struct acpi_pci_link *link)
 750{
 751        if (link->refcnt && link->irq.active && link->irq.initialized)
 752                return (acpi_pci_link_set(link, link->irq.active));
 753
 754        return 0;
 755}
 756
 757static void irqrouter_resume(void)
 758{
 759        struct acpi_pci_link *link;
 760
 761        list_for_each_entry(link, &acpi_link_list, list) {
 762                acpi_pci_link_resume(link);
 763        }
 764}
 765
 766static void acpi_pci_link_remove(struct acpi_device *device)
 767{
 768        struct acpi_pci_link *link;
 769
 770        link = acpi_driver_data(device);
 771
 772        mutex_lock(&acpi_link_lock);
 773        list_del(&link->list);
 774        mutex_unlock(&acpi_link_lock);
 775
 776        kfree(link);
 777}
 778
 779/*
 780 * modify acpi_irq_penalty[] from cmdline
 781 */
 782static int __init acpi_irq_penalty_update(char *str, int used)
 783{
 784        int i;
 785
 786        for (i = 0; i < 16; i++) {
 787                int retval;
 788                int irq;
 789
 790                retval = get_option(&str, &irq);
 791
 792                if (!retval)
 793                        break;  /* no number found */
 794
 795                if (irq < 0)
 796                        continue;
 797
 798                if (irq >= ARRAY_SIZE(acpi_irq_penalty))
 799                        continue;
 800
 801                if (used)
 802                        acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 803                else
 804                        acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 805
 806                if (retval != 2)        /* no next number */
 807                        break;
 808        }
 809        return 1;
 810}
 811
 812/*
 813 * We'd like PNP to call this routine for the
 814 * single ISA_USED value for each legacy device.
 815 * But instead it calls us with each POSSIBLE setting.
 816 * There is no ISA_POSSIBLE weight, so we simply use
 817 * the (small) PCI_USING penalty.
 818 */
 819void acpi_penalize_isa_irq(int irq, int active)
 820{
 821        if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
 822                if (active)
 823                        acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 824                else
 825                        acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
 826        }
 827}
 828
 829/*
 830 * Over-ride default table to reserve additional IRQs for use by ISA
 831 * e.g. acpi_irq_isa=5
 832 * Useful for telling ACPI how not to interfere with your ISA sound card.
 833 */
 834static int __init acpi_irq_isa(char *str)
 835{
 836        return acpi_irq_penalty_update(str, 1);
 837}
 838
 839__setup("acpi_irq_isa=", acpi_irq_isa);
 840
 841/*
 842 * Over-ride default table to free additional IRQs for use by PCI
 843 * e.g. acpi_irq_pci=7,15
 844 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 845 */
 846static int __init acpi_irq_pci(char *str)
 847{
 848        return acpi_irq_penalty_update(str, 0);
 849}
 850
 851__setup("acpi_irq_pci=", acpi_irq_pci);
 852
 853static int __init acpi_irq_nobalance_set(char *str)
 854{
 855        acpi_irq_balance = 0;
 856        return 1;
 857}
 858
 859__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 860
 861static int __init acpi_irq_balance_set(char *str)
 862{
 863        acpi_irq_balance = 1;
 864        return 1;
 865}
 866
 867__setup("acpi_irq_balance", acpi_irq_balance_set);
 868
 869static struct syscore_ops irqrouter_syscore_ops = {
 870        .resume = irqrouter_resume,
 871};
 872
 873void __init acpi_pci_link_init(void)
 874{
 875        if (acpi_noirq)
 876                return;
 877
 878        if (acpi_irq_balance == -1) {
 879                /* no command line switch: enable balancing in IOAPIC mode */
 880                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 881                        acpi_irq_balance = 1;
 882                else
 883                        acpi_irq_balance = 0;
 884        }
 885        register_syscore_ops(&irqrouter_syscore_ops);
 886        acpi_scan_add_handler(&pci_link_handler);
 887}
 888
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