LXR linux/drivers/acpi/pci

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
   4 *
   5 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
   6 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
   7 *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
   8 *
   9 * TBD: 
  10 *      1. Support more than one IRQ resource entry per link device (index).
  11 *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
  12 *         for IRQ management (e.g. start()->_SRS).
  13 */
  14
  15#include <linux/syscore_ops.h>
  16#include <linux/kernel.h>
  17#include <linux/module.h>
  18#include <linux/init.h>
  19#include <linux/types.h>
  20#include <linux/spinlock.h>
  21#include <linux/pm.h>
  22#include <linux/pci.h>
  23#include <linux/mutex.h>
  24#include <linux/slab.h>
  25#include <linux/acpi.h>
  26#include <linux/irq.h>
  27
  28#include "internal.h"
  29
  30#define _COMPONENT                      ACPI_PCI_COMPONENT
  31ACPI_MODULE_NAME("pci_link");
  32#define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  33#define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
  34#define ACPI_PCI_LINK_MAX_POSSIBLE      16
  35
  36static int acpi_pci_link_add(struct acpi_device *device,
  37                             const struct acpi_device_id *not_used);
  38static void acpi_pci_link_remove(struct acpi_device *device);
  39
  40static const struct acpi_device_id link_device_ids[] = {
  41        {"PNP0C0F", 0},
  42        {"", 0},
  43};
  44
  45static struct acpi_scan_handler pci_link_handler = {
  46        .ids = link_device_ids,
  47        .attach = acpi_pci_link_add,
  48        .detach = acpi_pci_link_remove,
  49};
  50
  51/*
  52 * If a link is initialized, we never change its active and initialized
  53 * later even the link is disable. Instead, we just repick the active irq
  54 */
  55struct acpi_pci_link_irq {
  56        u32 active;             /* Current IRQ */
  57        u8 triggering;          /* All IRQs */
  58        u8 polarity;            /* All IRQs */
  59        u8 resource_type;
  60        u8 possible_count;
  61        u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  62        u8 initialized:1;
  63        u8 reserved:7;
  64};
  65
  66struct acpi_pci_link {
  67        struct list_head                list;
  68        struct acpi_device              *device;
  69        struct acpi_pci_link_irq        irq;
  70        int                             refcnt;
  71};
  72
  73static LIST_HEAD(acpi_link_list);
  74static DEFINE_MUTEX(acpi_link_lock);
  75static int sci_irq = -1, sci_penalty;
  76
  77/* --------------------------------------------------------------------------
  78                            PCI Link Device Management
  79   -------------------------------------------------------------------------- */
  80
  81/*
  82 * set context (link) possible list from resource list
  83 */
  84static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
  85                                                void *context)
  86{
  87        struct acpi_pci_link *link = context;
  88        u32 i;
  89
  90        switch (resource->type) {
  91        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
  92        case ACPI_RESOURCE_TYPE_END_TAG:
  93                return AE_OK;
  94        case ACPI_RESOURCE_TYPE_IRQ:
  95                {
  96                        struct acpi_resource_irq *p = &resource->data.irq;
  97                        if (!p || !p->interrupt_count) {
  98                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
  99                                                  "Blank _PRS IRQ resource\n"));
 100                                return AE_OK;
 101                        }
 102                        for (i = 0;
 103                             (i < p->interrupt_count
 104                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 105                                if (!p->interrupts[i]) {
 106                                        printk(KERN_WARNING PREFIX
 107                                               "Invalid _PRS IRQ %d\n",
 108                                               p->interrupts[i]);
 109                                        continue;
 110                                }
 111                                link->irq.possible[i] = p->interrupts[i];
 112                                link->irq.possible_count++;
 113                        }
 114                        link->irq.triggering = p->triggering;
 115                        link->irq.polarity = p->polarity;
 116                        link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 117                        break;
 118                }
 119        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 120                {
 121                        struct acpi_resource_extended_irq *p =
 122                            &resource->data.extended_irq;
 123                        if (!p || !p->interrupt_count) {
 124                                printk(KERN_WARNING PREFIX
 125                                              "Blank _PRS EXT IRQ resource\n");
 126                                return AE_OK;
 127                        }
 128                        for (i = 0;
 129                             (i < p->interrupt_count
 130                              && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 131                                if (!p->interrupts[i]) {
 132                                        printk(KERN_WARNING PREFIX
 133                                               "Invalid _PRS IRQ %d\n",
 134                                               p->interrupts[i]);
 135                                        continue;
 136                                }
 137                                link->irq.possible[i] = p->interrupts[i];
 138                                link->irq.possible_count++;
 139                        }
 140                        link->irq.triggering = p->triggering;
 141                        link->irq.polarity = p->polarity;
 142                        link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 143                        break;
 144                }
 145        default:
 146                printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
 147                       resource->type);
 148                return AE_OK;
 149        }
 150
 151        return AE_CTRL_TERMINATE;
 152}
 153
 154static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 155{
 156        acpi_status status;
 157
 158        status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
 159                                     acpi_pci_link_check_possible, link);
 160        if (ACPI_FAILURE(status)) {
 161                acpi_handle_debug(link->device->handle, "_PRS not present or invalid");
 162                return 0;
 163        }
 164
 165        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 166                          "Found %d possible IRQs\n",
 167                          link->irq.possible_count));
 168
 169        return 0;
 170}
 171
 172static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
 173                                               void *context)
 174{
 175        int *irq = context;
 176
 177        switch (resource->type) {
 178        case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 179        case ACPI_RESOURCE_TYPE_END_TAG:
 180                return AE_OK;
 181        case ACPI_RESOURCE_TYPE_IRQ:
 182                {
 183                        struct acpi_resource_irq *p = &resource->data.irq;
 184                        if (!p || !p->interrupt_count) {
 185                                /*
 186                                 * IRQ descriptors may have no IRQ# bits set,
 187                                 * particularly those those w/ _STA disabled
 188                                 */
 189                                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 190                                                  "Blank _CRS IRQ resource\n"));
 191                                return AE_OK;
 192                        }
 193                        *irq = p->interrupts[0];
 194                        break;
 195                }
 196        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 197                {
 198                        struct acpi_resource_extended_irq *p =
 199                            &resource->data.extended_irq;
 200                        if (!p || !p->interrupt_count) {
 201                                /*
 202                                 * extended IRQ descriptors must
 203                                 * return at least 1 IRQ
 204                                 */
 205                                printk(KERN_WARNING PREFIX
 206                                              "Blank _CRS EXT IRQ resource\n");
 207                                return AE_OK;
 208                        }
 209                        *irq = p->interrupts[0];
 210                        break;
 211                }
 212                break;
 213        default:
 214                printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
 215                       resource->type);
 216                return AE_OK;
 217        }
 218
 219        return AE_CTRL_TERMINATE;
 220}
 221
 222/*
 223 * Run _CRS and set link->irq.active
 224 *
 225 * return value:
 226 * 0 - success
 227 * !0 - failure
 228 */
 229static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 230{
 231        int result = 0;
 232        acpi_status status;
 233        int irq = 0;
 234
 235        link->irq.active = 0;
 236
 237        /* in practice, status disabled is meaningless, ignore it */
 238        if (acpi_strict) {
 239                /* Query _STA, set link->device->status */
 240                result = acpi_bus_get_status(link->device);
 241                if (result) {
 242                        printk(KERN_ERR PREFIX "Unable to read status\n");
 243                        goto end;
 244                }
 245
 246                if (!link->device->status.enabled) {
 247                        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
 248                        return 0;
 249                }
 250        }
 251
 252        /* 
 253         * Query and parse _CRS to get the current IRQ assignment. 
 254         */
 255
 256        status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
 257                                     acpi_pci_link_check_current, &irq);
 258        if (ACPI_FAILURE(status)) {
 259                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
 260                result = -ENODEV;
 261                goto end;
 262        }
 263
 264        if (acpi_strict && !irq) {
 265                printk(KERN_ERR PREFIX "_CRS returned 0\n");
 266                result = -ENODEV;
 267        }
 268
 269        link->irq.active = irq;
 270
 271        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
 272
 273      end:
 274        return result;
 275}
 276
 277static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 278{
 279        int result;
 280        acpi_status status;
 281        struct {
 282                struct acpi_resource res;
 283                struct acpi_resource end;
 284        } *resource;
 285        struct acpi_buffer buffer = { 0, NULL };
 286
 287        if (!irq)
 288                return -EINVAL;
 289
 290        resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
 291        if (!resource)
 292                return -ENOMEM;
 293
 294        buffer.length = sizeof(*resource) + 1;
 295        buffer.pointer = resource;
 296
 297        switch (link->irq.resource_type) {
 298        case ACPI_RESOURCE_TYPE_IRQ:
 299                resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 300                resource->res.length = sizeof(struct acpi_resource);
 301                resource->res.data.irq.triggering = link->irq.triggering;
 302                resource->res.data.irq.polarity =
 303                    link->irq.polarity;
 304                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 305                        resource->res.data.irq.shareable =
 306                            ACPI_EXCLUSIVE;
 307                else
 308                        resource->res.data.irq.shareable = ACPI_SHARED;
 309                resource->res.data.irq.interrupt_count = 1;
 310                resource->res.data.irq.interrupts[0] = irq;
 311                break;
 312
 313        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 314                resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 315                resource->res.length = sizeof(struct acpi_resource);
 316                resource->res.data.extended_irq.producer_consumer =
 317                    ACPI_CONSUMER;
 318                resource->res.data.extended_irq.triggering =
 319                    link->irq.triggering;
 320                resource->res.data.extended_irq.polarity =
 321                    link->irq.polarity;
 322                if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 323                        resource->res.data.extended_irq.shareable =
 324                            ACPI_EXCLUSIVE;
 325                else
 326                        resource->res.data.extended_irq.shareable = ACPI_SHARED;
 327                resource->res.data.extended_irq.interrupt_count = 1;
 328                resource->res.data.extended_irq.interrupts[0] = irq;
 329                /* ignore resource_source, it's optional */
 330                break;
 331        default:
 332                printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
 333                result = -EINVAL;
 334                goto end;
 335
 336        }
 337        resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 338        resource->end.length = sizeof(struct acpi_resource);
 339
 340        /* Attempt to set the resource */
 341        status = acpi_set_current_resources(link->device->handle, &buffer);
 342
 343        /* check for total failure */
 344        if (ACPI_FAILURE(status)) {
 345                ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
 346                result = -ENODEV;
 347                goto end;
 348        }
 349
 350        /* Query _STA, set device->status */
 351        result = acpi_bus_get_status(link->device);
 352        if (result) {
 353                printk(KERN_ERR PREFIX "Unable to read status\n");
 354                goto end;
 355        }
 356        if (!link->device->status.enabled) {
 357                printk(KERN_WARNING PREFIX
 358                              "%s [%s] disabled and referenced, BIOS bug\n",
 359                              acpi_device_name(link->device),
 360                              acpi_device_bid(link->device));
 361        }
 362
 363        /* Query _CRS, set link->irq.active */
 364        result = acpi_pci_link_get_current(link);
 365        if (result) {
 366                goto end;
 367        }
 368
 369        /*
 370         * Is current setting not what we set?
 371         * set link->irq.active
 372         */
 373        if (link->irq.active != irq) {
 374                /*
 375                 * policy: when _CRS doesn't return what we just _SRS
 376                 * assume _SRS worked and override _CRS value.
 377                 */
 378                printk(KERN_WARNING PREFIX
 379                              "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 380                              acpi_device_name(link->device),
 381                              acpi_device_bid(link->device), link->irq.active, irq);
 382                link->irq.active = irq;
 383        }
 384
 385        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 386
 387      end:
 388        kfree(resource);
 389        return result;
 390}
 391
 392/* --------------------------------------------------------------------------
 393                            PCI Link IRQ Management
 394   -------------------------------------------------------------------------- */
 395
 396/*
 397 * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 398 * Link Devices to move the PIRQs around to minimize sharing.
 399 * 
 400 * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 401 * that the BIOS has already set to active.  This is necessary because
 402 * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 403 * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 404 * even if acpi_irq_nobalance is set.
 405 *
 406 * A tables of penalties avoids directing PCI interrupts to well known
 407 * ISA IRQs. Boot params are available to over-ride the default table:
 408 *
 409 * List interrupts that are free for PCI use.
 410 * acpi_irq_pci=n[,m]
 411 *
 412 * List interrupts that should not be used for PCI:
 413 * acpi_irq_isa=n[,m]
 414 *
 415 * Note that PCI IRQ routers have a list of possible IRQs,
 416 * which may not include the IRQs this table says are available.
 417 * 
 418 * Since this heuristic can't tell the difference between a link
 419 * that no device will attach to, vs. a link which may be shared
 420 * by multiple active devices -- it is not optimal.
 421 *
 422 * If interrupt performance is that important, get an IO-APIC system
 423 * with a pin dedicated to each device.  Or for that matter, an MSI
 424 * enabled system.
 425 */
 426
 427#define ACPI_MAX_ISA_IRQS       16
 428
 429#define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 430#define PIRQ_PENALTY_PCI_USING          (16*16*16)
 431#define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 432#define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 433#define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 434
 435static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
 436        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 437        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 438        PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 439        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 440        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 441        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 442        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 443        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 444        PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 445        0,                              /* IRQ9  PCI, often acpi */
 446        0,                              /* IRQ10 PCI */
 447        0,                              /* IRQ11 PCI */
 448        PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
 449        PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
 450        PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
 451        PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
 452        /* >IRQ15 */
 453};
 454
 455static int acpi_irq_pci_sharing_penalty(int irq)
 456{
 457        struct acpi_pci_link *link;
 458        int penalty = 0;
 459        int i;
 460
 461        list_for_each_entry(link, &acpi_link_list, list) {
 462                /*
 463                 * If a link is active, penalize its IRQ heavily
 464                 * so we try to choose a different IRQ.
 465                 */
 466                if (link->irq.active && link->irq.active == irq)
 467                        penalty += PIRQ_PENALTY_PCI_USING;
 468
 469                /*
 470                 * penalize the IRQs PCI might use, but not as severely.
 471                 */
 472                for (i = 0; i < link->irq.possible_count; i++)
 473                        if (link->irq.possible[i] == irq)
 474                                penalty += PIRQ_PENALTY_PCI_POSSIBLE /
 475                                        link->irq.possible_count;
 476        }
 477
 478        return penalty;
 479}
 480
 481static int acpi_irq_get_penalty(int irq)
 482{
 483        int penalty = 0;
 484
 485        if (irq == sci_irq)
 486                penalty += sci_penalty;
 487
 488        if (irq < ACPI_MAX_ISA_IRQS)
 489                return penalty + acpi_isa_irq_penalty[irq];
 490
 491        return penalty + acpi_irq_pci_sharing_penalty(irq);
 492}
 493
 494int __init acpi_irq_penalty_init(void)
 495{
 496        struct acpi_pci_link *link;
 497        int i;
 498
 499        /*
 500         * Update penalties to facilitate IRQ balancing.
 501         */
 502        list_for_each_entry(link, &acpi_link_list, list) {
 503
 504                /*
 505                 * reflect the possible and active irqs in the penalty table --
 506                 * useful for breaking ties.
 507                 */
 508                if (link->irq.possible_count) {
 509                        int penalty =
 510                            PIRQ_PENALTY_PCI_POSSIBLE /
 511                            link->irq.possible_count;
 512
 513                        for (i = 0; i < link->irq.possible_count; i++) {
 514                                if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
 515                                        acpi_isa_irq_penalty[link->irq.
 516                                                         possible[i]] +=
 517                                            penalty;
 518                        }
 519
 520                } else if (link->irq.active &&
 521                                (link->irq.active < ACPI_MAX_ISA_IRQS)) {
 522                        acpi_isa_irq_penalty[link->irq.active] +=
 523                            PIRQ_PENALTY_PCI_POSSIBLE;
 524                }
 525        }
 526
 527        return 0;
 528}
 529
 530static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
 531
 532static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 533{
 534        int irq;
 535        int i;
 536
 537        if (link->irq.initialized) {
 538                if (link->refcnt == 0)
 539                        /* This means the link is disabled but initialized */
 540                        acpi_pci_link_set(link, link->irq.active);
 541                return 0;
 542        }
 543
 544        /*
 545         * search for active IRQ in list of possible IRQs.
 546         */
 547        for (i = 0; i < link->irq.possible_count; ++i) {
 548                if (link->irq.active == link->irq.possible[i])
 549                        break;
 550        }
 551        /*
 552         * forget active IRQ that is not in possible list
 553         */
 554        if (i == link->irq.possible_count) {
 555                if (acpi_strict)
 556                        printk(KERN_WARNING PREFIX "_CRS %d not found"
 557                                      " in _PRS\n", link->irq.active);
 558                link->irq.active = 0;
 559        }
 560
 561        /*
 562         * if active found, use it; else pick entry from end of possible list.
 563         */
 564        if (link->irq.active)
 565                irq = link->irq.active;
 566        else
 567                irq = link->irq.possible[link->irq.possible_count - 1];
 568
 569        if (acpi_irq_balance || !link->irq.active) {
 570                /*
 571                 * Select the best IRQ.  This is done in reverse to promote
 572                 * the use of IRQs 9, 10, 11, and >15.
 573                 */
 574                for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 575                        if (acpi_irq_get_penalty(irq) >
 576                            acpi_irq_get_penalty(link->irq.possible[i]))
 577                                irq = link->irq.possible[i];
 578                }
 579        }
 580        if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
 581                printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
 582                            "Try pci=noacpi or acpi=off\n",
 583                            acpi_device_name(link->device),
 584                            acpi_device_bid(link->device));
 585                return -ENODEV;
 586        }
 587
 588        /* Attempt to enable the link device at this IRQ. */
 589        if (acpi_pci_link_set(link, irq)) {
 590                printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
 591                            "Try pci=noacpi or acpi=off\n",
 592                            acpi_device_name(link->device),
 593                            acpi_device_bid(link->device));
 594                return -ENODEV;
 595        } else {
 596                if (link->irq.active < ACPI_MAX_ISA_IRQS)
 597                        acpi_isa_irq_penalty[link->irq.active] +=
 598                                PIRQ_PENALTY_PCI_USING;
 599
 600                pr_info("%s [%s] enabled at IRQ %d\n",
 601                       acpi_device_name(link->device),
 602                       acpi_device_bid(link->device), link->irq.active);
 603        }
 604
 605        link->irq.initialized = 1;
 606        return 0;
 607}
 608
 609/*
 610 * acpi_pci_link_allocate_irq
 611 * success: return IRQ >= 0
 612 * failure: return -1
 613 */
 614int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
 615                               int *polarity, char **name)
 616{
 617        int result;
 618        struct acpi_device *device;
 619        struct acpi_pci_link *link;
 620
 621        result = acpi_bus_get_device(handle, &device);
 622        if (result) {
 623                printk(KERN_ERR PREFIX "Invalid link device\n");
 624                return -1;
 625        }
 626
 627        link = acpi_driver_data(device);
 628        if (!link) {
 629                printk(KERN_ERR PREFIX "Invalid link context\n");
 630                return -1;
 631        }
 632
 633        /* TBD: Support multiple index (IRQ) entries per Link Device */
 634        if (index) {
 635                printk(KERN_ERR PREFIX "Invalid index %d\n", index);
 636                return -1;
 637        }
 638
 639        mutex_lock(&acpi_link_lock);
 640        if (acpi_pci_link_allocate(link)) {
 641                mutex_unlock(&acpi_link_lock);
 642                return -1;
 643        }
 644
 645        if (!link->irq.active) {
 646                mutex_unlock(&acpi_link_lock);
 647                printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
 648                return -1;
 649        }
 650        link->refcnt++;
 651        mutex_unlock(&acpi_link_lock);
 652
 653        if (triggering)
 654                *triggering = link->irq.triggering;
 655        if (polarity)
 656                *polarity = link->irq.polarity;
 657        if (name)
 658                *name = acpi_device_bid(link->device);
 659        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 660                          "Link %s is referenced\n",
 661                          acpi_device_bid(link->device)));
 662        return link->irq.active;
 663}
 664
 665/*
 666 * We don't change link's irq information here.  After it is reenabled, we
 667 * continue use the info
 668 */
 669int acpi_pci_link_free_irq(acpi_handle handle)
 670{
 671        struct acpi_device *device;
 672        struct acpi_pci_link *link;
 673        acpi_status result;
 674
 675        result = acpi_bus_get_device(handle, &device);
 676        if (result) {
 677                printk(KERN_ERR PREFIX "Invalid link device\n");
 678                return -1;
 679        }
 680
 681        link = acpi_driver_data(device);
 682        if (!link) {
 683                printk(KERN_ERR PREFIX "Invalid link context\n");
 684                return -1;
 685        }
 686
 687        mutex_lock(&acpi_link_lock);
 688        if (!link->irq.initialized) {
 689                mutex_unlock(&acpi_link_lock);
 690                printk(KERN_ERR PREFIX "Link isn't initialized\n");
 691                return -1;
 692        }
 693#ifdef  FUTURE_USE
 694        /*
 695         * The Link reference count allows us to _DISable an unused link
 696         * and suspend time, and set it again  on resume.
 697         * However, 2.6.12 still has irq_router.resume
 698         * which blindly restores the link state.
 699         * So we disable the reference count method
 700         * to prevent duplicate acpi_pci_link_set()
 701         * which would harm some systems
 702         */
 703        link->refcnt--;
 704#endif
 705        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 706                          "Link %s is dereferenced\n",
 707                          acpi_device_bid(link->device)));
 708
 709        if (link->refcnt == 0)
 710                acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
 711
 712        mutex_unlock(&acpi_link_lock);
 713        return link->irq.active;
 714}
 715
 716/* --------------------------------------------------------------------------
 717                                 Driver Interface
 718   -------------------------------------------------------------------------- */
 719
 720static int acpi_pci_link_add(struct acpi_device *device,
 721                             const struct acpi_device_id *not_used)
 722{
 723        int result;
 724        struct acpi_pci_link *link;
 725        int i;
 726        int found = 0;
 727
 728        link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 729        if (!link)
 730                return -ENOMEM;
 731
 732        link->device = device;
 733        strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 734        strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 735        device->driver_data = link;
 736
 737        mutex_lock(&acpi_link_lock);
 738        result = acpi_pci_link_get_possible(link);
 739        if (result)
 740                goto end;
 741
 742        /* query and set link->irq.active */
 743        acpi_pci_link_get_current(link);
 744
 745        printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 746               acpi_device_bid(device));
 747        for (i = 0; i < link->irq.possible_count; i++) {
 748                if (link->irq.active == link->irq.possible[i]) {
 749                        printk(KERN_CONT " *%d", link->irq.possible[i]);
 750                        found = 1;
 751                } else
 752                        printk(KERN_CONT " %d", link->irq.possible[i]);
 753        }
 754
 755        printk(KERN_CONT ")");
 756
 757        if (!found)
 758                printk(KERN_CONT " *%d", link->irq.active);
 759
 760        if (!link->device->status.enabled)
 761                printk(KERN_CONT ", disabled.");
 762
 763        printk(KERN_CONT "\n");
 764
 765        list_add_tail(&link->list, &acpi_link_list);
 766
 767      end:
 768        /* disable all links -- to be activated on use */
 769        acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
 770        mutex_unlock(&acpi_link_lock);
 771
 772        if (result)
 773                kfree(link);
 774
 775        return result < 0 ? result : 1;
 776}
 777
 778static int acpi_pci_link_resume(struct acpi_pci_link *link)
 779{
 780        if (link->refcnt && link->irq.active && link->irq.initialized)
 781                return (acpi_pci_link_set(link, link->irq.active));
 782
 783        return 0;
 784}
 785
 786static void irqrouter_resume(void)
 787{
 788        struct acpi_pci_link *link;
 789
 790        list_for_each_entry(link, &acpi_link_list, list) {
 791                acpi_pci_link_resume(link);
 792        }
 793}
 794
 795static void acpi_pci_link_remove(struct acpi_device *device)
 796{
 797        struct acpi_pci_link *link;
 798
 799        link = acpi_driver_data(device);
 800
 801        mutex_lock(&acpi_link_lock);
 802        list_del(&link->list);
 803        mutex_unlock(&acpi_link_lock);
 804
 805        kfree(link);
 806}
 807
 808/*
 809 * modify acpi_isa_irq_penalty[] from cmdline
 810 */
 811static int __init acpi_irq_penalty_update(char *str, int used)
 812{
 813        int i;
 814
 815        for (i = 0; i < 16; i++) {
 816                int retval;
 817                int irq;
 818                int new_penalty;
 819
 820                retval = get_option(&str, &irq);
 821
 822                if (!retval)
 823                        break;  /* no number found */
 824
 825                /* see if this is a ISA IRQ */
 826                if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
 827                        continue;
 828
 829                if (used)
 830                        new_penalty = acpi_isa_irq_penalty[irq] +
 831                                        PIRQ_PENALTY_ISA_USED;
 832                else
 833                        new_penalty = 0;
 834
 835                acpi_isa_irq_penalty[irq] = new_penalty;
 836                if (retval != 2)        /* no next number */
 837                        break;
 838        }
 839        return 1;
 840}
 841
 842/*
 843 * We'd like PNP to call this routine for the
 844 * single ISA_USED value for each legacy device.
 845 * But instead it calls us with each POSSIBLE setting.
 846 * There is no ISA_POSSIBLE weight, so we simply use
 847 * the (small) PCI_USING penalty.
 848 */
 849void acpi_penalize_isa_irq(int irq, int active)
 850{
 851        if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
 852                acpi_isa_irq_penalty[irq] +=
 853                  (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
 854}
 855
 856bool acpi_isa_irq_available(int irq)
 857{
 858        return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
 859                    acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
 860}
 861
 862void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
 863{
 864        sci_irq = irq;
 865
 866        if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
 867            polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
 868                sci_penalty = PIRQ_PENALTY_PCI_USING;
 869        else
 870                sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
 871}
 872
 873/*
 874 * Over-ride default table to reserve additional IRQs for use by ISA
 875 * e.g. acpi_irq_isa=5
 876 * Useful for telling ACPI how not to interfere with your ISA sound card.
 877 */
 878static int __init acpi_irq_isa(char *str)
 879{
 880        return acpi_irq_penalty_update(str, 1);
 881}
 882
 883__setup("acpi_irq_isa=", acpi_irq_isa);
 884
 885/*
 886 * Over-ride default table to free additional IRQs for use by PCI
 887 * e.g. acpi_irq_pci=7,15
 888 * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 889 */
 890static int __init acpi_irq_pci(char *str)
 891{
 892        return acpi_irq_penalty_update(str, 0);
 893}
 894
 895__setup("acpi_irq_pci=", acpi_irq_pci);
 896
 897static int __init acpi_irq_nobalance_set(char *str)
 898{
 899        acpi_irq_balance = 0;
 900        return 1;
 901}
 902
 903__setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 904
 905static int __init acpi_irq_balance_set(char *str)
 906{
 907        acpi_irq_balance = 1;
 908        return 1;
 909}
 910
 911__setup("acpi_irq_balance", acpi_irq_balance_set);
 912
 913static struct syscore_ops irqrouter_syscore_ops = {
 914        .resume = irqrouter_resume,
 915};
 916
 917void __init acpi_pci_link_init(void)
 918{
 919        if (acpi_noirq)
 920                return;
 921
 922        if (acpi_irq_balance == -1) {
 923                /* no command line switch: enable balancing in IOAPIC mode */
 924                if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
 925                        acpi_irq_balance = 1;
 926                else
 927                        acpi_irq_balance = 0;
 928        }
 929        register_syscore_ops(&irqrouter_syscore_ops);
 930        acpi_scan_add_handler(&pci_link_handler);
 931}
 932