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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/sysdev.h>
  33 #include <linux/kernel.h>
  34 #include <linux/module.h>
  35 #include <linux/init.h>
  36 #include <linux/types.h>
  37 #include <linux/proc_fs.h>
  38 #include <linux/spinlock.h>
  39 #include <linux/pm.h>
  40 #include <linux/pci.h>
  41 #include <linux/mutex.h>
  42
  43 #include <acpi/acpi_bus.h>
  44 #include <acpi/acpi_drivers.h>
  45
  46 #define _COMPONENT              ACPI_PCI_COMPONENT
  47 ACPI_MODULE_NAME("pci_link")
  48 #define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  49 #define ACPI_PCI_LINK_HID               "PNP0C0F"
  50 #define ACPI_PCI_LINK_DRIVER_NAME       "ACPI PCI Interrupt Link Driver"
  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 static int acpi_pci_link_add(struct acpi_device *device);
  56 static int acpi_pci_link_remove(struct acpi_device *device, int type);
  57
  58 static struct acpi_driver acpi_pci_link_driver = {
  59         .name = ACPI_PCI_LINK_DRIVER_NAME,
  60         .class = ACPI_PCI_LINK_CLASS,
  61         .ids = ACPI_PCI_LINK_HID,
  62         .ops = {
  63                 .add = acpi_pci_link_add,
  64                 .remove = acpi_pci_link_remove,
  65                 },
  66 };
  67
  68 /*
  69  * If a link is initialized, we never change its active and initialized
  70  * later even the link is disable. Instead, we just repick the active irq
  71  */
  72 struct acpi_pci_link_irq {
  73         u8 active;              /* Current IRQ */
  74         u8 triggering;          /* All IRQs */
  75         u8 polarity;    /* All IRQs */
  76         u8 resource_type;
  77         u8 possible_count;
  78         u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  79         u8 initialized:1;
  80         u8 reserved:7;
  81 };
  82
  83 struct acpi_pci_link {
  84         struct list_head node;
  85         struct acpi_device *device;
  86         struct acpi_pci_link_irq irq;
  87         int refcnt;
  88 };
  89
  90 static struct {
  91         int count;
  92         struct list_head entries;
  93 } acpi_link;
  94 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  */
 103 static acpi_status
 104 acpi_pci_link_check_possible(struct acpi_resource *resource, void *context)
 105 {
 106         struct acpi_pci_link *link = (struct acpi_pci_link *)context;
 107         u32 i = 0;
 108
 109
 110         switch (resource->type) {
 111         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 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                                 printk(KERN_WARNING PREFIX "Blank IRQ resource\n");
 118                                 return AE_OK;
 119                         }
 120                         for (i = 0;
 121                              (i < p->interrupt_count
 122                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 123                                 if (!p->interrupts[i]) {
 124                                         printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
 125                                                       p->interrupts[i]);
 126                                         continue;
 127                                 }
 128                                 link->irq.possible[i] = p->interrupts[i];
 129                                 link->irq.possible_count++;
 130                         }
 131                         link->irq.triggering = p->triggering;
 132                         link->irq.polarity = p->polarity;
 133                         link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 134                         break;
 135                 }
 136         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 137                 {
 138                         struct acpi_resource_extended_irq *p =
 139                             &resource->data.extended_irq;
 140                         if (!p || !p->interrupt_count) {
 141                                 printk(KERN_WARNING PREFIX
 142                                               "Blank EXT IRQ resource\n");
 143                                 return AE_OK;
 144                         }
 145                         for (i = 0;
 146                              (i < p->interrupt_count
 147                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 148                                 if (!p->interrupts[i]) {
 149                                         printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
 150                                                       p->interrupts[i]);
 151                                         continue;
 152                                 }
 153                                 link->irq.possible[i] = p->interrupts[i];
 154                                 link->irq.possible_count++;
 155                         }
 156                         link->irq.triggering = p->triggering;
 157                         link->irq.polarity = p->polarity;
 158                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 159                         break;
 160                 }
 161         default:
 162                 printk(KERN_ERR PREFIX "Resource is not an IRQ entry\n");
 163                 return AE_OK;
 164         }
 165
 166         return AE_CTRL_TERMINATE;
 167 }
 168
 169 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 170 {
 171         acpi_status status;
 172
 173
 174         if (!link)
 175                 return -EINVAL;
 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
 191 static acpi_status
 192 acpi_pci_link_check_current(struct acpi_resource *resource, void *context)
 193 {
 194         int *irq = (int *)context;
 195
 196
 197         switch (resource->type) {
 198         case ACPI_RESOURCE_TYPE_IRQ:
 199                 {
 200                         struct acpi_resource_irq *p = &resource->data.irq;
 201                         if (!p || !p->interrupt_count) {
 202                                 /*
 203                                  * IRQ descriptors may have no IRQ# bits set,
 204                                  * particularly those those w/ _STA disabled
 205                                  */
 206                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 207                                                   "Blank IRQ resource\n"));
 208                                 return AE_OK;
 209                         }
 210                         *irq = p->interrupts[0];
 211                         break;
 212                 }
 213         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 214                 {
 215                         struct acpi_resource_extended_irq *p =
 216                             &resource->data.extended_irq;
 217                         if (!p || !p->interrupt_count) {
 218                                 /*
 219                                  * extended IRQ descriptors must
 220                                  * return at least 1 IRQ
 221                                  */
 222                                 printk(KERN_WARNING PREFIX
 223                                               "Blank EXT IRQ resource\n");
 224                                 return AE_OK;
 225                         }
 226                         *irq = p->interrupts[0];
 227                         break;
 228                 }
 229                 break;
 230         default:
 231                 printk(KERN_ERR PREFIX "Resource %d isn't an IRQ\n", resource->type);
 232         case ACPI_RESOURCE_TYPE_END_TAG:
 233                 return AE_OK;
 234         }
 235         return AE_CTRL_TERMINATE;
 236 }
 237
 238 /*
 239  * Run _CRS and set link->irq.active
 240  *
 241  * return value:
 242  * 0 - success
 243  * !0 - failure
 244  */
 245 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 246 {
 247         int result = 0;
 248         acpi_status status = AE_OK;
 249         int irq = 0;
 250
 251         if (!link)
 252                 return -EINVAL;
 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
 296 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 297 {
 298         int result = 0;
 299         acpi_status status = AE_OK;
 300         struct {
 301                 struct acpi_resource res;
 302                 struct acpi_resource end;
 303         } *resource;
 304         struct acpi_buffer buffer = { 0, NULL };
 305
 306
 307         if (!link || !irq)
 308                 return -EINVAL;
 309
 310         resource = kmalloc(sizeof(*resource) + 1, GFP_ATOMIC);
 311         if (!resource)
 312                 return -ENOMEM;
 313
 314         memset(resource, 0, sizeof(*resource) + 1);
 315         buffer.length = sizeof(*resource) + 1;
 316         buffer.pointer = resource;
 317
 318         switch (link->irq.resource_type) {
 319         case ACPI_RESOURCE_TYPE_IRQ:
 320                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 321                 resource->res.length = sizeof(struct acpi_resource);
 322                 resource->res.data.irq.triggering = link->irq.triggering;
 323                 resource->res.data.irq.polarity =
 324                     link->irq.polarity;
 325                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 326                         resource->res.data.irq.sharable =
 327                             ACPI_EXCLUSIVE;
 328                 else
 329                         resource->res.data.irq.sharable = ACPI_SHARED;
 330                 resource->res.data.irq.interrupt_count = 1;
 331                 resource->res.data.irq.interrupts[0] = irq;
 332                 break;
 333
 334         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 335                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 336                 resource->res.length = sizeof(struct acpi_resource);
 337                 resource->res.data.extended_irq.producer_consumer =
 338                     ACPI_CONSUMER;
 339                 resource->res.data.extended_irq.triggering =
 340                     link->irq.triggering;
 341                 resource->res.data.extended_irq.polarity =
 342                     link->irq.polarity;
 343                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 344                         resource->res.data.irq.sharable =
 345                             ACPI_EXCLUSIVE;
 346                 else
 347                         resource->res.data.irq.sharable = ACPI_SHARED;
 348                 resource->res.data.extended_irq.interrupt_count = 1;
 349                 resource->res.data.extended_irq.interrupts[0] = irq;
 350                 /* ignore resource_source, it's optional */
 351                 break;
 352         default:
 353                 printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
 354                 result = -EINVAL;
 355                 goto end;
 356
 357         }
 358         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 359
 360         /* Attempt to set the resource */
 361         status = acpi_set_current_resources(link->device->handle, &buffer);
 362
 363         /* check for total failure */
 364         if (ACPI_FAILURE(status)) {
 365                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
 366                 result = -ENODEV;
 367                 goto end;
 368         }
 369
 370         /* Query _STA, set device->status */
 371         result = acpi_bus_get_status(link->device);
 372         if (result) {
 373                 printk(KERN_ERR PREFIX "Unable to read status\n");
 374                 goto end;
 375         }
 376         if (!link->device->status.enabled) {
 377                 printk(KERN_WARNING PREFIX
 378                               "%s [%s] disabled and referenced, BIOS bug\n",
 379                               acpi_device_name(link->device),
 380                               acpi_device_bid(link->device));
 381         }
 382
 383         /* Query _CRS, set link->irq.active */
 384         result = acpi_pci_link_get_current(link);
 385         if (result) {
 386                 goto end;
 387         }
 388
 389         /*
 390          * Is current setting not what we set?
 391          * set link->irq.active
 392          */
 393         if (link->irq.active != irq) {
 394                 /*
 395                  * policy: when _CRS doesn't return what we just _SRS
 396                  * assume _SRS worked and override _CRS value.
 397                  */
 398                 printk(KERN_WARNING PREFIX
 399                               "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 400                               acpi_device_name(link->device),
 401                               acpi_device_bid(link->device), link->irq.active, irq);
 402                 link->irq.active = irq;
 403         }
 404
 405         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 406
 407       end:
 408         kfree(resource);
 409         return result;
 410 }
 411
 412 /* --------------------------------------------------------------------------
 413                             PCI Link IRQ Management
 414    -------------------------------------------------------------------------- */
 415
 416 /*
 417  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 418  * Link Devices to move the PIRQs around to minimize sharing.
 419  *
 420  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 421  * that the BIOS has already set to active.  This is necessary because
 422  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 423  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 424  * even if acpi_irq_nobalance is set.
 425  *
 426  * A tables of penalties avoids directing PCI interrupts to well known
 427  * ISA IRQs. Boot params are available to over-ride the default table:
 428  *
 429  * List interrupts that are free for PCI use.
 430  * acpi_irq_pci=n[,m]
 431  *
 432  * List interrupts that should not be used for PCI:
 433  * acpi_irq_isa=n[,m]
 434  *
 435  * Note that PCI IRQ routers have a list of possible IRQs,
 436  * which may not include the IRQs this table says are available.
 437  *
 438  * Since this heuristic can't tell the difference between a link
 439  * that no device will attach to, vs. a link which may be shared
 440  * by multiple active devices -- it is not optimal.
 441  *
 442  * If interrupt performance is that important, get an IO-APIC system
 443  * with a pin dedicated to each device.  Or for that matter, an MSI
 444  * enabled system.
 445  */
 446
 447 #define ACPI_MAX_IRQS           256
 448 #define ACPI_MAX_ISA_IRQ        16
 449
 450 #define PIRQ_PENALTY_PCI_AVAILABLE      (0)
 451 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 452 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
 453 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 454 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 455 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 456
 457 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 458         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 459         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 460         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 461         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 462         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 463         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 464         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 465         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 466         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 467         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
 468         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
 469         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
 470         PIRQ_PENALTY_ISA_USED,  /* IRQ12 mouse */
 471         PIRQ_PENALTY_ISA_USED,  /* IRQ13 fpe, sometimes */
 472         PIRQ_PENALTY_ISA_USED,  /* IRQ14 ide0 */
 473         PIRQ_PENALTY_ISA_USED,  /* IRQ15 ide1 */
 474         /* >IRQ15 */
 475 };
 476
 477 int __init acpi_irq_penalty_init(void)
 478 {
 479         struct list_head *node = NULL;
 480         struct acpi_pci_link *link = NULL;
 481         int i = 0;
 482
 483
 484         /*
 485          * Update penalties to facilitate IRQ balancing.
 486          */
 487         list_for_each(node, &acpi_link.entries) {
 488
 489                 link = list_entry(node, struct acpi_pci_link, node);
 490                 if (!link) {
 491                         printk(KERN_ERR PREFIX "Invalid link context\n");
 492                         continue;
 493                 }
 494
 495                 /*
 496                  * reflect the possible and active irqs in the penalty table --
 497                  * useful for breaking ties.
 498                  */
 499                 if (link->irq.possible_count) {
 500                         int penalty =
 501                             PIRQ_PENALTY_PCI_POSSIBLE /
 502                             link->irq.possible_count;
 503
 504                         for (i = 0; i < link->irq.possible_count; i++) {
 505                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
 506                                         acpi_irq_penalty[link->irq.
 507                                                          possible[i]] +=
 508                                             penalty;
 509                         }
 510
 511                 } else if (link->irq.active) {
 512                         acpi_irq_penalty[link->irq.active] +=
 513                             PIRQ_PENALTY_PCI_POSSIBLE;
 514                 }
 515         }
 516         /* Add a penalty for the SCI */
 517         acpi_irq_penalty[acpi_fadt.sci_int] += PIRQ_PENALTY_PCI_USING;
 518
 519         return 0;
 520 }
 521
 522 static int acpi_irq_balance;    /* 0: static, 1: balance */
 523
 524 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 525 {
 526         int irq;
 527         int i;
 528
 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
 563         if (acpi_irq_balance || !link->irq.active) {
 564                 /*
 565                  * Select the best IRQ.  This is done in reverse to promote
 566                  * the use of IRQs 9, 10, 11, and >15.
 567                  */
 568                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 569                         if (acpi_irq_penalty[irq] >
 570                             acpi_irq_penalty[link->irq.possible[i]])
 571                                 irq = link->irq.possible[i];
 572                 }
 573         }
 574
 575         /* Attempt to enable the link device at this IRQ. */
 576         if (acpi_pci_link_set(link, irq)) {
 577                 printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
 578                             "Try pci=noacpi or acpi=off\n",
 579                             acpi_device_name(link->device),
 580                             acpi_device_bid(link->device));
 581                 return -ENODEV;
 582         } else {
 583                 acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 584                 printk(PREFIX "%s [%s] enabled at IRQ %d\n",
 585                        acpi_device_name(link->device),
 586                        acpi_device_bid(link->device), link->irq.active);
 587         }
 588
 589         link->irq.initialized = 1;
 590
 591         return 0;
 592 }
 593
 594 /*
 595  * acpi_pci_link_allocate_irq
 596  * success: return IRQ >= 0
 597  * failure: return -1
 598  */
 599
 600 int
 601 acpi_pci_link_allocate_irq(acpi_handle handle,
 602                            int index,
 603                            int *triggering, int *polarity, char **name)
 604 {
 605         int result = 0;
 606         struct acpi_device *device = NULL;
 607         struct acpi_pci_link *link = NULL;
 608
 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 = (struct acpi_pci_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 = NULL;
 661         struct acpi_pci_link *link = NULL;
 662         acpi_status result;
 663
 664
 665         result = acpi_bus_get_device(handle, &device);
 666         if (result) {
 667                 printk(KERN_ERR PREFIX "Invalid link device\n");
 668                 return -1;
 669         }
 670
 671         link = (struct acpi_pci_link *)acpi_driver_data(device);
 672         if (!link) {
 673                 printk(KERN_ERR PREFIX "Invalid link context\n");
 674                 return -1;
 675         }
 676
 677         mutex_lock(&acpi_link_lock);
 678         if (!link->irq.initialized) {
 679                 mutex_unlock(&acpi_link_lock);
 680                 printk(KERN_ERR PREFIX "Link isn't initialized\n");
 681                 return -1;
 682         }
 683 #ifdef  FUTURE_USE
 684         /*
 685          * The Link reference count allows us to _DISable an unused link
 686          * and suspend time, and set it again  on resume.
 687          * However, 2.6.12 still has irq_router.resume
 688          * which blindly restores the link state.
 689          * So we disable the reference count method
 690          * to prevent duplicate acpi_pci_link_set()
 691          * which would harm some systems
 692          */
 693         link->refcnt--;
 694 #endif
 695         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 696                           "Link %s is dereferenced\n",
 697                           acpi_device_bid(link->device)));
 698
 699         if (link->refcnt == 0) {
 700                 acpi_ut_evaluate_object(link->device->handle, "_DIS", 0, NULL);
 701         }
 702         mutex_unlock(&acpi_link_lock);
 703         return (link->irq.active);
 704 }
 705
 706 /* --------------------------------------------------------------------------
 707                                  Driver Interface
 708    -------------------------------------------------------------------------- */
 709
 710 static int acpi_pci_link_add(struct acpi_device *device)
 711 {
 712         int result = 0;
 713         struct acpi_pci_link *link = NULL;
 714         int i = 0;
 715         int found = 0;
 716
 717
 718         if (!device)
 719                 return -EINVAL;
 720
 721         link = kmalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 722         if (!link)
 723                 return -ENOMEM;
 724         memset(link, 0, sizeof(struct acpi_pci_link));
 725
 726         link->device = device;
 727         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 728         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 729         acpi_driver_data(device) = link;
 730
 731         mutex_lock(&acpi_link_lock);
 732         result = acpi_pci_link_get_possible(link);
 733         if (result)
 734                 goto end;
 735
 736         /* query and set link->irq.active */
 737         acpi_pci_link_get_current(link);
 738
 739         printk(PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 740                acpi_device_bid(device));
 741         for (i = 0; i < link->irq.possible_count; i++) {
 742                 if (link->irq.active == link->irq.possible[i]) {
 743                         printk(" *%d", link->irq.possible[i]);
 744                         found = 1;
 745                 } else
 746                         printk(" %d", link->irq.possible[i]);
 747         }
 748
 749         printk(")");
 750
 751         if (!found)
 752                 printk(" *%d", link->irq.active);
 753
 754         if (!link->device->status.enabled)
 755                 printk(", disabled.");
 756
 757         printk("\n");
 758
 759         /* TBD: Acquire/release lock */
 760         list_add_tail(&link->node, &acpi_link.entries);
 761         acpi_link.count++;
 762
 763       end:
 764         /* disable all links -- to be activated on use */
 765         acpi_ut_evaluate_object(device->handle, "_DIS", 0, NULL);
 766         mutex_unlock(&acpi_link_lock);
 767
 768         if (result)
 769                 kfree(link);
 770
 771         return result;
 772 }
 773
 774 static int acpi_pci_link_resume(struct acpi_pci_link *link)
 775 {
 776
 777         if (link->refcnt && link->irq.active && link->irq.initialized)
 778                 return (acpi_pci_link_set(link, link->irq.active));
 779         else
 780                 return 0;
 781 }
 782
 783 /*
 784  * FIXME: this is a workaround to avoid nasty warning.  It will be removed
 785  * after every device calls pci_disable_device in .resume.
 786  */
 787 int acpi_in_resume;
 788 static int irqrouter_resume(struct sys_device *dev)
 789 {
 790         struct list_head *node = NULL;
 791         struct acpi_pci_link *link = NULL;
 792
 793
 794         /* Make sure SCI is enabled again (Apple firmware bug?) */
 795         acpi_set_register(ACPI_BITREG_SCI_ENABLE, 1, ACPI_MTX_DO_NOT_LOCK);
 796
 797         acpi_in_resume = 1;
 798         list_for_each(node, &acpi_link.entries) {
 799                 link = list_entry(node, struct acpi_pci_link, node);
 800                 if (!link) {
 801                         printk(KERN_ERR PREFIX "Invalid link context\n");
 802                         continue;
 803                 }
 804                 acpi_pci_link_resume(link);
 805         }
 806         acpi_in_resume = 0;
 807         return 0;
 808 }
 809
 810 static int acpi_pci_link_remove(struct acpi_device *device, int type)
 811 {
 812         struct acpi_pci_link *link = NULL;
 813
 814
 815         if (!device || !acpi_driver_data(device))
 816                 return -EINVAL;
 817
 818         link = (struct acpi_pci_link *)acpi_driver_data(device);
 819
 820         mutex_lock(&acpi_link_lock);
 821         list_del(&link->node);
 822         mutex_unlock(&acpi_link_lock);
 823
 824         kfree(link);
 825
 826         return 0;
 827 }
 828
 829 /*
 830  * modify acpi_irq_penalty[] from cmdline
 831  */
 832 static int __init acpi_irq_penalty_update(char *str, int used)
 833 {
 834         int i;
 835
 836         for (i = 0; i < 16; i++) {
 837                 int retval;
 838                 int irq;
 839
 840                 retval = get_option(&str, &irq);
 841
 842                 if (!retval)
 843                         break;  /* no number found */
 844
 845                 if (irq < 0)
 846                         continue;
 847
 848                 if (irq >= ACPI_MAX_IRQS)
 849                         continue;
 850
 851                 if (used)
 852                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 853                 else
 854                         acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 855
 856                 if (retval != 2)        /* no next number */
 857                         break;
 858         }
 859         return 1;
 860 }
 861
 862 /*
 863  * We'd like PNP to call this routine for the
 864  * single ISA_USED value for each legacy device.
 865  * But instead it calls us with each POSSIBLE setting.
 866  * There is no ISA_POSSIBLE weight, so we simply use
 867  * the (small) PCI_USING penalty.
 868  */
 869 void acpi_penalize_isa_irq(int irq, int active)
 870 {
 871         if (active)
 872                 acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 873         else
 874                 acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
 875 }
 876
 877 /*
 878  * Over-ride default table to reserve additional IRQs for use by ISA
 879  * e.g. acpi_irq_isa=5
 880  * Useful for telling ACPI how not to interfere with your ISA sound card.
 881  */
 882 static int __init acpi_irq_isa(char *str)
 883 {
 884         return acpi_irq_penalty_update(str, 1);
 885 }
 886
 887 __setup("acpi_irq_isa=", acpi_irq_isa);
 888
 889 /*
 890  * Over-ride default table to free additional IRQs for use by PCI
 891  * e.g. acpi_irq_pci=7,15
 892  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 893  */
 894 static int __init acpi_irq_pci(char *str)
 895 {
 896         return acpi_irq_penalty_update(str, 0);
 897 }
 898
 899 __setup("acpi_irq_pci=", acpi_irq_pci);
 900
 901 static int __init acpi_irq_nobalance_set(char *str)
 902 {
 903         acpi_irq_balance = 0;
 904         return 1;
 905 }
 906
 907 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 908
 909 int __init acpi_irq_balance_set(char *str)
 910 {
 911         acpi_irq_balance = 1;
 912         return 1;
 913 }
 914
 915 __setup("acpi_irq_balance", acpi_irq_balance_set);
 916
 917 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
 918 static struct sysdev_class irqrouter_sysdev_class = {
 919         set_kset_name("irqrouter"),
 920         .resume = irqrouter_resume,
 921 };
 922
 923 static struct sys_device device_irqrouter = {
 924         .id = 0,
 925         .cls = &irqrouter_sysdev_class,
 926 };
 927
 928 static int __init irqrouter_init_sysfs(void)
 929 {
 930         int error;
 931
 932
 933         if (acpi_disabled || acpi_noirq)
 934                 return 0;
 935
 936         error = sysdev_class_register(&irqrouter_sysdev_class);
 937         if (!error)
 938                 error = sysdev_register(&device_irqrouter);
 939
 940         return error;
 941 }
 942
 943 device_initcall(irqrouter_init_sysfs);
 944
 945 static int __init acpi_pci_link_init(void)
 946 {
 947
 948         if (acpi_noirq)
 949                 return 0;
 950
 951         acpi_link.count = 0;
 952         INIT_LIST_HEAD(&acpi_link.entries);
 953
 954         if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
 955                 return -ENODEV;
 956
 957         return 0;
 958 }
 959
 960 subsys_initcall(acpi_pci_link_init);