drivers/acpi/pci_link.c

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