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        resource->end.length = sizeof(struct acpi_resource);
 358
 359        /* Attempt to set the resource */
 360        status = acpi_set_current_resources(link->device->handle, &buffer);
 361
 362        /* check for total failure */
 363        if (ACPI_FAILURE(status)) {
 364                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
 365                result = -ENODEV;
 366                goto end;
 367        }
 368
 369        /* Query _STA, set device->status */
 370        result = acpi_bus_get_status(link->device);
 371        if (result) {
 372                printk(KERN_ERR PREFIX "Unable to read status\n");
 373                goto end;
 374        }
 375        if (!link->device->status.enabled) {
 376                printk(KERN_WARNING PREFIX
 377                              "%s [%s] disabled and referenced, BIOS bug\n",
 378                              acpi_device_name(link->device),
 379                              acpi_device_bid(link->device));
 380        }
 381
 382        /* Query _CRS, set link->irq.active */
 383        result = acpi_pci_link_get_current(link);
 384        if (result) {
 385                goto end;
 386        }
 387
 388        /*
 389         * Is current setting not what we set?
 390         * set link->irq.active
 391         */
 392        if (link->irq.active != irq) {
 393                /*
 394                 * policy: when _CRS doesn't return what we just _SRS
 395                 * assume _SRS worked and override _CRS value.
 396                 */
 397                printk(KERN_WARNING PREFIX
 398                              "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 399                              acpi_device_name(link->device),
 400                              acpi_device_bid(link->device), link->irq.active, irq);
 401                link->irq.active = irq;
 402        }
 403
 404        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 405
 406      end:
 407        kfree(resource);
 408        return result;
 409}
 410
 411/* --------------------------------------------------------------------------
 412                            PCI Link IRQ Management
 413   -------------------------------------------------------------------------- */
 414
 415/*
 416 * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 417 * Link Devices to move the PIRQs around to minimize sharing.
 418 * 
 419 * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 420 * that the BIOS has already set to active.  This is necessary because
 421 * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 422 * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 423 * even if acpi_irq_nobalance is set.
 424 *
 425 * A tables of penalties avoids directing PCI interrupts to well known
 426 * ISA IRQs. Boot params are available to over-ride the default table:
 427 *
 428 * List interrupts that are free for PCI use.
 429 * acpi_irq_pci=n[,m]
 430 *
 431 * List interrupts that should not be used for PCI:
 432 * acpi_irq_isa=n[,m]
 433 *
 434 * Note that PCI IRQ routers have a list of possible IRQs,
 435 * which may not include the IRQs this table says are available.
 436 * 
 437 * Since this heuristic can't tell the difference between a link
 438 * that no device will attach to, vs. a link which may be shared
 439 * by multiple active devices -- it is not optimal.
 440 *
 441 * If interrupt performance is that important, get an IO-APIC system
 442 * with a pin dedicated to each device.  Or for that matter, an MSI
 443 * enabled system.
 444 */
 445
 446#define ACPI_MAX_IRQS           256
 447#define ACPI_MAX_ISA_IRQ        16
 448
 449#define PIRQ_PENALTY_PCI_AVAILABLE      (0)
 450#define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 451#define PIRQ_PENALTY_PCI_USING          (16*16*16)
 452#define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 453#define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 454#define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 455
 456static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 457        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 458        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 459        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 460        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 461        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 462        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 463        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 464        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 465        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 466        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
 467        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
 468        PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
 469        PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
 470        PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
 471        PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
 472        PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
 473        /* >IRQ15 */
 474};
 475
 476int __init acpi_irq_penalty_init(void)
 477{
 478        struct acpi_pci_link *link;
 479        int i;
 480
 481        /*
 482         * Update penalties to facilitate IRQ balancing.
 483         */
 484        list_for_each_entry(link, &acpi_link_list, list) {
 485
 486                /*
 487                 * reflect the possible and active irqs in the penalty table --
 488                 * useful for breaking ties.
 489                 */
 490                if (link->irq.possible_count) {
 491                        int penalty =
 492                            PIRQ_PENALTY_PCI_POSSIBLE /
 493                            link->irq.possible_count;
 494
 495                        for (i = 0; i < link->irq.possible_count; i++) {
 496                                if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
 497                                        acpi_irq_penalty[link->irq.
 498                                                         possible[i]] +=
 499                                            penalty;
 500                        }
 501
 502                } else if (link->irq.active) {
 503                        acpi_irq_penalty[link->irq.active] +=
 504                            PIRQ_PENALTY_PCI_POSSIBLE;
 505                }
 506        }
 507        /* Add a penalty for the SCI */
 508        acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
 509        return 0;
 510}
 511
 512static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 513
 514static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 515{
 516        int irq;
 517        int i;
 518
 519        if (link->irq.initialized) {
 520                if (link->refcnt == 0)
 521                        /* This means the link is disabled but initialized */
 522                        acpi_pci_link_set(link, link->irq.active);
 523                return 0;
 524        }
 525
 526        /*
 527         * search for active IRQ in list of possible IRQs.
 528         */
 529        for (i = 0; i < link->irq.possible_count; ++i) {
 530                if (link->irq.active == link->irq.possible[i])
 531                        break;
 532        }
 533        /*
 534         * forget active IRQ that is not in possible list
 535         */
 536        if (i == link->irq.possible_count) {
 537                if (acpi_strict)
 538                        printk(KERN_WARNING PREFIX "_CRS %d not found"
 539                                      " in _PRS\n", link->irq.active);
 540                link->irq.active = 0;
 541        }
 542
 543        /*
 544         * if active found, use it; else pick entry from end of possible list.
 545         */
 546        if (link->irq.active)
 547                irq = link->irq.active;
 548        else
 549                irq = link->irq.possible[link->irq.possible_count - 1];
 550
 551        if (acpi_irq_balance || !link->irq.active) {
 552                /*
 553                 * Select the best IRQ.  This is done in reverse to promote
 554                 * the use of IRQs 9, 10, 11, and >15.
 555                 */
 556                for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 557                        if (acpi_irq_penalty[irq] >
 558                            acpi_irq_penalty[link->irq.possible[i]])
 559                                irq = link->irq.possible[i];
 560                }
 561        }
 562
 563        /* Attempt to enable the link device at this IRQ. */
 564        if (acpi_pci_link_set(link, irq)) {
 565                printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
 566                            "Try pci=noacpi or acpi=off\n",
 567                            acpi_device_name(link->device),
 568                            acpi_device_bid(link->device));
 569                return -ENODEV;
 570        } else {
 571                acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 572                printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
 573                       acpi_device_name(link->device),
 574                       acpi_device_bid(link->device), link->irq.active);
 575        }
 576
 577        link->irq.initialized = 1;
 578        return 0;
 579}
 580
 581/*
 582 * acpi_pci_link_allocate_irq
 583 * success: return IRQ >= 0
 584 * failure: return -1
 585 */
 586int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 587                               int *polarity, char **name)
 588{
 589        int result;
 590        struct acpi_device *device;
 591        struct acpi_pci_link *link;
 592
 593        result = acpi_bus_get_device(handle, &device);
 594        if (result) {
 595                printk(KERN_ERR PREFIX "Invalid link device\n");
 596                return -1;
 597        }
 598
 599        link = acpi_driver_data(device);
 600        if (!link) {
 601                printk(KERN_ERR PREFIX "Invalid link context\n");
 602                return -1;
 603        }
 604
 605        /* TBD: Support multiple index (IRQ) entries per Link Device */
 606        if (index) {
 607                printk(KERN_ERR PREFIX "Invalid index %d\n", index);
 608                return -1;
 609        }
 610
 611        mutex_lock(&acpi_link_lock);
 612        if (acpi_pci_link_allocate(link)) {
 613                mutex_unlock(&acpi_link_lock);
 614                return -1;
 615        }
 616
 617        if (!link->irq.active) {
 618                mutex_unlock(&acpi_link_lock);
 619                printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
 620                return -1;
 621        }
 622        link->refcnt++;
 623        mutex_unlock(&acpi_link_lock);
 624
 625        if (triggering)
 626                *triggering = link->irq.triggering;
 627        if (polarity)
 628                *polarity = link->irq.polarity;
 629        if (name)
 630                *name = acpi_device_bid(link->device);
 631        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 632                          "Link %s is referenced\n",
 633                          acpi_device_bid(link->device)));
 634        return (link->irq.active);
 635}
 636
 637/*
 638 * We don't change link's irq information here.  After it is reenabled, we
 639 * continue use the info
 640 */
 641int acpi_pci_link_free_irq(acpi_handle handle)
 642{
 643        struct acpi_device *device;
 644        struct acpi_pci_link *link;
 645        acpi_status result;
 646
 647        result = acpi_bus_get_device(handle, &device);
 648        if (result) {
 649                printk(KERN_ERR PREFIX "Invalid link device\n");
 650                return -1;
 651        }
 652
 653        link = acpi_driver_data(device);
 654        if (!link) {
 655                printk(KERN_ERR PREFIX "Invalid link context\n");
 656                return -1;
 657        }
 658
 659        mutex_lock(&acpi_link_lock);
 660        if (!link->irq.initialized) {
 661                mutex_unlock(&acpi_link_lock);
 662                printk(KERN_ERR PREFIX "Link isn't initialized\n");
 663                return -1;
 664        }
 665#ifdef  FUTURE_USE
 666        /*
 667         * The Link reference count allows us to _DISable an unused link
 668         * and suspend time, and set it again  on resume.
 669         * However, 2.6.12 still has irq_router.resume
 670         * which blindly restores the link state.
 671         * So we disable the reference count method
 672         * to prevent duplicate acpi_pci_link_set()
 673         * which would harm some systems
 674         */
 675        link->refcnt--;
 676#endif
 677        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 678                          "Link %s is dereferenced\n",
 679                          acpi_device_bid(link->device)));
 680
 681        if (link->refcnt == 0)
 682                acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 683
 684        mutex_unlock(&acpi_link_lock);
 685        return (link->irq.active);
 686}
 687
 688/* --------------------------------------------------------------------------
 689                                 Driver Interface
 690   -------------------------------------------------------------------------- */
 691
 692static int acpi_pci_link_add(struct acpi_device *device,
 693                             const struct acpi_device_id *not_used)
 694{
 695        int result;
 696        struct acpi_pci_link *link;
 697        int i;
 698        int found = 0;
 699
 700        link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 701        if (!link)
 702                return -ENOMEM;
 703
 704        link->device = device;
 705        strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 706        strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 707        device->driver_data = link;
 708
 709        mutex_lock(&acpi_link_lock);
 710        result = acpi_pci_link_get_possible(link);
 711        if (result)
 712                goto end;
 713
 714        /* query and set link->irq.active */
 715        acpi_pci_link_get_current(link);
 716
 717        printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 718               acpi_device_bid(device));
 719        for (i = 0; i < link->irq.possible_count; i++) {
 720                if (link->irq.active == link->irq.possible[i]) {
 721                        printk(KERN_CONT " *%d", link->irq.possible[i]);
 722                        found = 1;
 723                } else
 724                        printk(KERN_CONT " %d", link->irq.possible[i]);
 725        }
 726
 727        printk(KERN_CONT ")");
 728
 729        if (!found)
 730                printk(KERN_CONT " *%d", link->irq.active);
 731
 732        if (!link->device->status.enabled)
 733                printk(KERN_CONT ", disabled.");
 734
 735        printk(KERN_CONT "\n");
 736
 737        list_add_tail(&link->list, &acpi_link_list);
 738
 739      end:
 740        /* disable all links -- to be activated on use */
 741        acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
 742        mutex_unlock(&acpi_link_lock);
 743
 744        if (result)
 745                kfree(link);
 746
 747        return result < 0 ? result : 1;
 748}
 749
 750static int acpi_pci_link_resume(struct acpi_pci_link *link)
 751{
 752        if (link->refcnt && link->irq.active && link->irq.initialized)
 753                return (acpi_pci_link_set(link, link->irq.active));
 754
 755        return 0;
 756}
 757
 758static void irqrouter_resume(void)
 759{
 760        struct acpi_pci_link *link;
 761
 762        list_for_each_entry(link, &acpi_link_list, list) {
 763                acpi_pci_link_resume(link);
 764        }
 765}
 766
 767static void acpi_pci_link_remove(struct acpi_device *device)
 768{
 769        struct acpi_pci_link *link;
 770
 771        link = acpi_driver_data(device);
 772
 773        mutex_lock(&acpi_link_lock);
 774        list_del(&link->list);
 775        mutex_unlock(&acpi_link_lock);
 776
 777        kfree(link);
 778}
 779
 780/*
 781 * modify acpi_irq_penalty[] from cmdline
 782 */
 783static int __init acpi_irq_penalty_update(char *str, int used)
 784{
 785        int i;
 786
 787        for (i = 0; i < 16; i++) {
 788                int retval;
 789                int irq;
 790
 791                retval = get_option(&str, &irq);
 792
 793                if (!retval)
 794                        break;  /* no number found */
 795
 796                if (irq < 0)
 797                        continue;
 798
 799                if (irq >= ARRAY_SIZE(acpi_irq_penalty))
 800                        continue;
 801
 802                if (used)
 803                        acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 804                else
 805                        acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 806
 807                if (retval != 2)        /* no next number */
 808                        break;
 809        }
 810        return 1;
 811}
 812
 813/*
 814 * We'd like PNP to call this routine for the
 815 * single ISA_USED value for each legacy device.
 816 * But instead it calls us with each POSSIBLE setting.
 817 * There is no ISA_POSSIBLE weight, so we simply use
 818 * the (small) PCI_USING penalty.
 819 */
 820void acpi_penalize_isa_irq(int irq, int active)
 821{
 822        if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
 823                if (active)
 824                        acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 825                else
 826                        acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
 827        }
 828}
 829
 830/*
 831 * Over-ride default table to reserve additional IRQs for use by ISA
 832 * e.g. acpi_irq_isa=5
 833 * Useful for telling ACPI how not to interfere with your ISA sound card.
 834 */
 835static int __init acpi_irq_isa(char *str)
 836{
 837        return acpi_irq_penalty_update(str, 1);
 838}
 839
 840__setup("acpi_irq_isa=", acpi_irq_isa);
 841
 842/*
 843 * Over-ride default table to free additional IRQs for use by PCI
 844 * e.g. acpi_irq_pci=7,15
 845 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 846 */
 847static int __init acpi_irq_pci(char *str)
 848{
 849        return acpi_irq_penalty_update(str, 0);
 850}
 851
 852__setup("acpi_irq_pci=", acpi_irq_pci);
 853
 854static int __init acpi_irq_nobalance_set(char *str)
 855{
 856        acpi_irq_balance = 0;
 857        return 1;
 858}
 859
 860__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 861
 862static int __init acpi_irq_balance_set(char *str)
 863{
 864        acpi_irq_balance = 1;
 865        return 1;
 866}
 867
 868__setup("acpi_irq_balance", acpi_irq_balance_set);
 869
 870static struct syscore_ops irqrouter_syscore_ops = {
 871        .resume = irqrouter_resume,
 872};
 873
 874void __init acpi_pci_link_init(void)
 875{
 876        if (acpi_noirq)
 877                return;
 878
 879        if (acpi_irq_balance == -1) {
 880                /* no command line switch: enable balancing in IOAPIC mode */
 881                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 882                        acpi_irq_balance = 1;
 883                else
 884                        acpi_irq_balance = 0;
 885        }
 886        register_syscore_ops(&irqrouter_syscore_ops);
 887        acpi_scan_add_handler(&pci_link_handler);
 888}
 889
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