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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
  42 #include <acpi/acpi_bus.h>
  43 #include <acpi/acpi_drivers.h>
  44
  45 #define _COMPONENT              ACPI_PCI_COMPONENT
  46 ACPI_MODULE_NAME("pci_link")
  47 #define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
  48 #define ACPI_PCI_LINK_HID               "PNP0C0F"
  49 #define ACPI_PCI_LINK_DRIVER_NAME       "ACPI PCI Interrupt Link Driver"
  50 #define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
  51 #define ACPI_PCI_LINK_FILE_INFO         "info"
  52 #define ACPI_PCI_LINK_FILE_STATUS       "state"
  53 #define ACPI_PCI_LINK_MAX_POSSIBLE 16
  54 static int acpi_pci_link_add(struct acpi_device *device);
  55 static int acpi_pci_link_remove(struct acpi_device *device, int type);
  56
  57 static struct acpi_driver acpi_pci_link_driver = {
  58         .name = ACPI_PCI_LINK_DRIVER_NAME,
  59         .class = ACPI_PCI_LINK_CLASS,
  60         .ids = ACPI_PCI_LINK_HID,
  61         .ops = {
  62                 .add = acpi_pci_link_add,
  63                 .remove = acpi_pci_link_remove,
  64                 },
  65 };
  66
  67 /*
  68  * If a link is initialized, we never change its active and initialized
  69  * later even the link is disable. Instead, we just repick the active irq
  70  */
  71 struct acpi_pci_link_irq {
  72         u8 active;              /* Current IRQ */
  73         u8 triggering;          /* All IRQs */
  74         u8 polarity;    /* All IRQs */
  75         u8 resource_type;
  76         u8 possible_count;
  77         u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
  78         u8 initialized:1;
  79         u8 reserved:7;
  80 };
  81
  82 struct acpi_pci_link {
  83         struct list_head node;
  84         struct acpi_device *device;
  85         acpi_handle handle;
  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 DECLARE_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         ACPI_FUNCTION_TRACE("acpi_pci_link_check_possible");
 110
 111         switch (resource->type) {
 112         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
 113                 return_ACPI_STATUS(AE_OK);
 114         case ACPI_RESOURCE_TYPE_IRQ:
 115                 {
 116                         struct acpi_resource_irq *p = &resource->data.irq;
 117                         if (!p || !p->interrupt_count) {
 118                                 ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 119                                                   "Blank IRQ resource\n"));
 120                                 return_ACPI_STATUS(AE_OK);
 121                         }
 122                         for (i = 0;
 123                              (i < p->interrupt_count
 124                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 125                                 if (!p->interrupts[i]) {
 126                                         ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 127                                                           "Invalid IRQ %d\n",
 128                                                           p->interrupts[i]));
 129                                         continue;
 130                                 }
 131                                 link->irq.possible[i] = p->interrupts[i];
 132                                 link->irq.possible_count++;
 133                         }
 134                         link->irq.triggering = p->triggering;
 135                         link->irq.polarity = p->polarity;
 136                         link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
 137                         break;
 138                 }
 139         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 140                 {
 141                         struct acpi_resource_extended_irq *p =
 142                             &resource->data.extended_irq;
 143                         if (!p || !p->interrupt_count) {
 144                                 ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 145                                                   "Blank EXT IRQ resource\n"));
 146                                 return_ACPI_STATUS(AE_OK);
 147                         }
 148                         for (i = 0;
 149                              (i < p->interrupt_count
 150                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
 151                                 if (!p->interrupts[i]) {
 152                                         ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 153                                                           "Invalid IRQ %d\n",
 154                                                           p->interrupts[i]));
 155                                         continue;
 156                                 }
 157                                 link->irq.possible[i] = p->interrupts[i];
 158                                 link->irq.possible_count++;
 159                         }
 160                         link->irq.triggering = p->triggering;
 161                         link->irq.polarity = p->polarity;
 162                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 163                         break;
 164                 }
 165         default:
 166                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 167                                   "Resource is not an IRQ entry\n"));
 168                 return_ACPI_STATUS(AE_OK);
 169         }
 170
 171         return_ACPI_STATUS(AE_CTRL_TERMINATE);
 172 }
 173
 174 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
 175 {
 176         acpi_status status;
 177
 178         ACPI_FUNCTION_TRACE("acpi_pci_link_get_possible");
 179
 180         if (!link)
 181                 return_VALUE(-EINVAL);
 182
 183         status = acpi_walk_resources(link->handle, METHOD_NAME__PRS,
 184                                      acpi_pci_link_check_possible, link);
 185         if (ACPI_FAILURE(status)) {
 186                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRS\n"));
 187                 return_VALUE(-ENODEV);
 188         }
 189
 190         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 191                           "Found %d possible IRQs\n",
 192                           link->irq.possible_count));
 193
 194         return_VALUE(0);
 195 }
 196
 197 static acpi_status
 198 acpi_pci_link_check_current(struct acpi_resource *resource, void *context)
 199 {
 200         int *irq = (int *)context;
 201
 202         ACPI_FUNCTION_TRACE("acpi_pci_link_check_current");
 203
 204         switch (resource->type) {
 205         case ACPI_RESOURCE_TYPE_IRQ:
 206                 {
 207                         struct acpi_resource_irq *p = &resource->data.irq;
 208                         if (!p || !p->interrupt_count) {
 209                                 /*
 210                                  * IRQ descriptors may have no IRQ# bits set,
 211                                  * particularly those those w/ _STA disabled
 212                                  */
 213                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 214                                                   "Blank IRQ resource\n"));
 215                                 return_ACPI_STATUS(AE_OK);
 216                         }
 217                         *irq = p->interrupts[0];
 218                         break;
 219                 }
 220         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 221                 {
 222                         struct acpi_resource_extended_irq *p =
 223                             &resource->data.extended_irq;
 224                         if (!p || !p->interrupt_count) {
 225                                 /*
 226                                  * extended IRQ descriptors must
 227                                  * return at least 1 IRQ
 228                                  */
 229                                 ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 230                                                   "Blank EXT IRQ resource\n"));
 231                                 return_ACPI_STATUS(AE_OK);
 232                         }
 233                         *irq = p->interrupts[0];
 234                         break;
 235                 }
 236                 break;
 237         default:
 238                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Resource %d isn't an IRQ\n", resource->type));
 239         case ACPI_RESOURCE_TYPE_END_TAG:
 240                 return_ACPI_STATUS(AE_OK);
 241         }
 242         return_ACPI_STATUS(AE_CTRL_TERMINATE);
 243 }
 244
 245 /*
 246  * Run _CRS and set link->irq.active
 247  *
 248  * return value:
 249  * 0 - success
 250  * !0 - failure
 251  */
 252 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
 253 {
 254         int result = 0;
 255         acpi_status status = AE_OK;
 256         int irq = 0;
 257
 258         ACPI_FUNCTION_TRACE("acpi_pci_link_get_current");
 259
 260         if (!link || !link->handle)
 261                 return_VALUE(-EINVAL);
 262
 263         link->irq.active = 0;
 264
 265         /* in practice, status disabled is meaningless, ignore it */
 266         if (acpi_strict) {
 267                 /* Query _STA, set link->device->status */
 268                 result = acpi_bus_get_status(link->device);
 269                 if (result) {
 270                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 271                                           "Unable to read status\n"));
 272                         goto end;
 273                 }
 274
 275                 if (!link->device->status.enabled) {
 276                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
 277                         return_VALUE(0);
 278                 }
 279         }
 280
 281         /*
 282          * Query and parse _CRS to get the current IRQ assignment.
 283          */
 284
 285         status = acpi_walk_resources(link->handle, METHOD_NAME__CRS,
 286                                      acpi_pci_link_check_current, &irq);
 287         if (ACPI_FAILURE(status)) {
 288                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _CRS\n"));
 289                 result = -ENODEV;
 290                 goto end;
 291         }
 292
 293         if (acpi_strict && !irq) {
 294                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "_CRS returned 0\n"));
 295                 result = -ENODEV;
 296         }
 297
 298         link->irq.active = irq;
 299
 300         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
 301
 302       end:
 303         return_VALUE(result);
 304 }
 305
 306 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
 307 {
 308         int result = 0;
 309         acpi_status status = AE_OK;
 310         struct {
 311                 struct acpi_resource res;
 312                 struct acpi_resource end;
 313         } *resource;
 314         struct acpi_buffer buffer = { 0, NULL };
 315
 316         ACPI_FUNCTION_TRACE("acpi_pci_link_set");
 317
 318         if (!link || !irq)
 319                 return_VALUE(-EINVAL);
 320
 321         resource = kmalloc(sizeof(*resource) + 1, GFP_ATOMIC);
 322         if (!resource)
 323                 return_VALUE(-ENOMEM);
 324
 325         memset(resource, 0, sizeof(*resource) + 1);
 326         buffer.length = sizeof(*resource) + 1;
 327         buffer.pointer = resource;
 328
 329         switch (link->irq.resource_type) {
 330         case ACPI_RESOURCE_TYPE_IRQ:
 331                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
 332                 resource->res.length = sizeof(struct acpi_resource);
 333                 resource->res.data.irq.triggering = link->irq.triggering;
 334                 resource->res.data.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.irq.interrupt_count = 1;
 342                 resource->res.data.irq.interrupts[0] = irq;
 343                 break;
 344
 345         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
 346                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
 347                 resource->res.length = sizeof(struct acpi_resource);
 348                 resource->res.data.extended_irq.producer_consumer =
 349                     ACPI_CONSUMER;
 350                 resource->res.data.extended_irq.triggering =
 351                     link->irq.triggering;
 352                 resource->res.data.extended_irq.polarity =
 353                     link->irq.polarity;
 354                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
 355                         resource->res.data.irq.sharable =
 356                             ACPI_EXCLUSIVE;
 357                 else
 358                         resource->res.data.irq.sharable = ACPI_SHARED;
 359                 resource->res.data.extended_irq.interrupt_count = 1;
 360                 resource->res.data.extended_irq.interrupts[0] = irq;
 361                 /* ignore resource_source, it's optional */
 362                 break;
 363         default:
 364                 printk("ACPI BUG: resource_type %d\n", link->irq.resource_type);
 365                 result = -EINVAL;
 366                 goto end;
 367
 368         }
 369         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
 370
 371         /* Attempt to set the resource */
 372         status = acpi_set_current_resources(link->handle, &buffer);
 373
 374         /* check for total failure */
 375         if (ACPI_FAILURE(status)) {
 376                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _SRS\n"));
 377                 result = -ENODEV;
 378                 goto end;
 379         }
 380
 381         /* Query _STA, set device->status */
 382         result = acpi_bus_get_status(link->device);
 383         if (result) {
 384                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Unable to read status\n"));
 385                 goto end;
 386         }
 387         if (!link->device->status.enabled) {
 388                 printk(KERN_WARNING PREFIX
 389                        "%s [%s] disabled and referenced, BIOS bug.\n",
 390                        acpi_device_name(link->device),
 391                        acpi_device_bid(link->device));
 392         }
 393
 394         /* Query _CRS, set link->irq.active */
 395         result = acpi_pci_link_get_current(link);
 396         if (result) {
 397                 goto end;
 398         }
 399
 400         /*
 401          * Is current setting not what we set?
 402          * set link->irq.active
 403          */
 404         if (link->irq.active != irq) {
 405                 /*
 406                  * policy: when _CRS doesn't return what we just _SRS
 407                  * assume _SRS worked and override _CRS value.
 408                  */
 409                 printk(KERN_WARNING PREFIX
 410                        "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
 411                        acpi_device_name(link->device),
 412                        acpi_device_bid(link->device), link->irq.active, irq);
 413                 link->irq.active = irq;
 414         }
 415
 416         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
 417
 418       end:
 419         kfree(resource);
 420         return_VALUE(result);
 421 }
 422
 423 /* --------------------------------------------------------------------------
 424                             PCI Link IRQ Management
 425    -------------------------------------------------------------------------- */
 426
 427 /*
 428  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
 429  * Link Devices to move the PIRQs around to minimize sharing.
 430  *
 431  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
 432  * that the BIOS has already set to active.  This is necessary because
 433  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
 434  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
 435  * even if acpi_irq_nobalance is set.
 436  *
 437  * A tables of penalties avoids directing PCI interrupts to well known
 438  * ISA IRQs. Boot params are available to over-ride the default table:
 439  *
 440  * List interrupts that are free for PCI use.
 441  * acpi_irq_pci=n[,m]
 442  *
 443  * List interrupts that should not be used for PCI:
 444  * acpi_irq_isa=n[,m]
 445  *
 446  * Note that PCI IRQ routers have a list of possible IRQs,
 447  * which may not include the IRQs this table says are available.
 448  *
 449  * Since this heuristic can't tell the difference between a link
 450  * that no device will attach to, vs. a link which may be shared
 451  * by multiple active devices -- it is not optimal.
 452  *
 453  * If interrupt performance is that important, get an IO-APIC system
 454  * with a pin dedicated to each device.  Or for that matter, an MSI
 455  * enabled system.
 456  */
 457
 458 #define ACPI_MAX_IRQS           256
 459 #define ACPI_MAX_ISA_IRQ        16
 460
 461 #define PIRQ_PENALTY_PCI_AVAILABLE      (0)
 462 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
 463 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
 464 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
 465 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
 466 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
 467
 468 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
 469         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
 470         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
 471         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
 472         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
 473         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
 474         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
 475         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
 476         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
 477         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
 478         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
 479         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
 480         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
 481         PIRQ_PENALTY_ISA_USED,  /* IRQ12 mouse */
 482         PIRQ_PENALTY_ISA_USED,  /* IRQ13 fpe, sometimes */
 483         PIRQ_PENALTY_ISA_USED,  /* IRQ14 ide0 */
 484         PIRQ_PENALTY_ISA_USED,  /* IRQ15 ide1 */
 485         /* >IRQ15 */
 486 };
 487
 488 int __init acpi_irq_penalty_init(void)
 489 {
 490         struct list_head *node = NULL;
 491         struct acpi_pci_link *link = NULL;
 492         int i = 0;
 493
 494         ACPI_FUNCTION_TRACE("acpi_irq_penalty_init");
 495
 496         /*
 497          * Update penalties to facilitate IRQ balancing.
 498          */
 499         list_for_each(node, &acpi_link.entries) {
 500
 501                 link = list_entry(node, struct acpi_pci_link, node);
 502                 if (!link) {
 503                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 504                                           "Invalid link context\n"));
 505                         continue;
 506                 }
 507
 508                 /*
 509                  * reflect the possible and active irqs in the penalty table --
 510                  * useful for breaking ties.
 511                  */
 512                 if (link->irq.possible_count) {
 513                         int penalty =
 514                             PIRQ_PENALTY_PCI_POSSIBLE /
 515                             link->irq.possible_count;
 516
 517                         for (i = 0; i < link->irq.possible_count; i++) {
 518                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
 519                                         acpi_irq_penalty[link->irq.
 520                                                          possible[i]] +=
 521                                             penalty;
 522                         }
 523
 524                 } else if (link->irq.active) {
 525                         acpi_irq_penalty[link->irq.active] +=
 526                             PIRQ_PENALTY_PCI_POSSIBLE;
 527                 }
 528         }
 529         /* Add a penalty for the SCI */
 530         acpi_irq_penalty[acpi_fadt.sci_int] += PIRQ_PENALTY_PCI_USING;
 531
 532         return_VALUE(0);
 533 }
 534
 535 static int acpi_irq_balance;    /* 0: static, 1: balance */
 536
 537 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
 538 {
 539         int irq;
 540         int i;
 541
 542         ACPI_FUNCTION_TRACE("acpi_pci_link_allocate");
 543
 544         if (link->irq.initialized) {
 545                 if (link->refcnt == 0)
 546                         /* This means the link is disabled but initialized */
 547                         acpi_pci_link_set(link, link->irq.active);
 548                 return_VALUE(0);
 549         }
 550
 551         /*
 552          * search for active IRQ in list of possible IRQs.
 553          */
 554         for (i = 0; i < link->irq.possible_count; ++i) {
 555                 if (link->irq.active == link->irq.possible[i])
 556                         break;
 557         }
 558         /*
 559          * forget active IRQ that is not in possible list
 560          */
 561         if (i == link->irq.possible_count) {
 562                 if (acpi_strict)
 563                         printk(KERN_WARNING PREFIX "_CRS %d not found"
 564                                " in _PRS\n", link->irq.active);
 565                 link->irq.active = 0;
 566         }
 567
 568         /*
 569          * if active found, use it; else pick entry from end of possible list.
 570          */
 571         if (link->irq.active) {
 572                 irq = link->irq.active;
 573         } else {
 574                 irq = link->irq.possible[link->irq.possible_count - 1];
 575         }
 576
 577         if (acpi_irq_balance || !link->irq.active) {
 578                 /*
 579                  * Select the best IRQ.  This is done in reverse to promote
 580                  * the use of IRQs 9, 10, 11, and >15.
 581                  */
 582                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
 583                         if (acpi_irq_penalty[irq] >
 584                             acpi_irq_penalty[link->irq.possible[i]])
 585                                 irq = link->irq.possible[i];
 586                 }
 587         }
 588
 589         /* Attempt to enable the link device at this IRQ. */
 590         if (acpi_pci_link_set(link, irq)) {
 591                 printk(PREFIX
 592                        "Unable to set IRQ for %s [%s] (likely buggy ACPI BIOS).\n"
 593                        "Try pci=noacpi or acpi=off\n",
 594                        acpi_device_name(link->device),
 595                        acpi_device_bid(link->device));
 596                 return_VALUE(-ENODEV);
 597         } else {
 598                 acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
 599                 printk(PREFIX "%s [%s] enabled at IRQ %d\n",
 600                        acpi_device_name(link->device),
 601                        acpi_device_bid(link->device), link->irq.active);
 602         }
 603
 604         link->irq.initialized = 1;
 605
 606         return_VALUE(0);
 607 }
 608
 609 /*
 610  * acpi_pci_link_allocate_irq
 611  * success: return IRQ >= 0
 612  * failure: return -1
 613  */
 614
 615 int
 616 acpi_pci_link_allocate_irq(acpi_handle handle,
 617                            int index,
 618                            int *triggering, int *polarity, char **name)
 619 {
 620         int result = 0;
 621         struct acpi_device *device = NULL;
 622         struct acpi_pci_link *link = NULL;
 623
 624         ACPI_FUNCTION_TRACE("acpi_pci_link_allocate_irq");
 625
 626         result = acpi_bus_get_device(handle, &device);
 627         if (result) {
 628                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link device\n"));
 629                 return_VALUE(-1);
 630         }
 631
 632         link = (struct acpi_pci_link *)acpi_driver_data(device);
 633         if (!link) {
 634                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
 635                 return_VALUE(-1);
 636         }
 637
 638         /* TBD: Support multiple index (IRQ) entries per Link Device */
 639         if (index) {
 640                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid index %d\n", index));
 641                 return_VALUE(-1);
 642         }
 643
 644         down(&acpi_link_lock);
 645         if (acpi_pci_link_allocate(link)) {
 646                 up(&acpi_link_lock);
 647                 return_VALUE(-1);
 648         }
 649
 650         if (!link->irq.active) {
 651                 up(&acpi_link_lock);
 652                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Link active IRQ is 0!\n"));
 653                 return_VALUE(-1);
 654         }
 655         link->refcnt++;
 656         up(&acpi_link_lock);
 657
 658         if (triggering)
 659                 *triggering = link->irq.triggering;
 660         if (polarity)
 661                 *polarity = link->irq.polarity;
 662         if (name)
 663                 *name = acpi_device_bid(link->device);
 664         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 665                           "Link %s is referenced\n",
 666                           acpi_device_bid(link->device)));
 667         return_VALUE(link->irq.active);
 668 }
 669
 670 /*
 671  * We don't change link's irq information here.  After it is reenabled, we
 672  * continue use the info
 673  */
 674 int acpi_pci_link_free_irq(acpi_handle handle)
 675 {
 676         struct acpi_device *device = NULL;
 677         struct acpi_pci_link *link = NULL;
 678         acpi_status result;
 679
 680         ACPI_FUNCTION_TRACE("acpi_pci_link_free_irq");
 681
 682         result = acpi_bus_get_device(handle, &device);
 683         if (result) {
 684                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link device\n"));
 685                 return_VALUE(-1);
 686         }
 687
 688         link = (struct acpi_pci_link *)acpi_driver_data(device);
 689         if (!link) {
 690                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
 691                 return_VALUE(-1);
 692         }
 693
 694         down(&acpi_link_lock);
 695         if (!link->irq.initialized) {
 696                 up(&acpi_link_lock);
 697                 ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Link isn't initialized\n"));
 698                 return_VALUE(-1);
 699         }
 700 #ifdef  FUTURE_USE
 701         /*
 702          * The Link reference count allows us to _DISable an unused link
 703          * and suspend time, and set it again  on resume.
 704          * However, 2.6.12 still has irq_router.resume
 705          * which blindly restores the link state.
 706          * So we disable the reference count method
 707          * to prevent duplicate acpi_pci_link_set()
 708          * which would harm some systems
 709          */
 710         link->refcnt--;
 711 #endif
 712         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 713                           "Link %s is dereferenced\n",
 714                           acpi_device_bid(link->device)));
 715
 716         if (link->refcnt == 0) {
 717                 acpi_ut_evaluate_object(link->handle, "_DIS", 0, NULL);
 718         }
 719         up(&acpi_link_lock);
 720         return_VALUE(link->irq.active);
 721 }
 722
 723 /* --------------------------------------------------------------------------
 724                                  Driver Interface
 725    -------------------------------------------------------------------------- */
 726
 727 static int acpi_pci_link_add(struct acpi_device *device)
 728 {
 729         int result = 0;
 730         struct acpi_pci_link *link = NULL;
 731         int i = 0;
 732         int found = 0;
 733
 734         ACPI_FUNCTION_TRACE("acpi_pci_link_add");
 735
 736         if (!device)
 737                 return_VALUE(-EINVAL);
 738
 739         link = kmalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
 740         if (!link)
 741                 return_VALUE(-ENOMEM);
 742         memset(link, 0, sizeof(struct acpi_pci_link));
 743
 744         link->device = device;
 745         link->handle = device->handle;
 746         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
 747         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
 748         acpi_driver_data(device) = link;
 749
 750         down(&acpi_link_lock);
 751         result = acpi_pci_link_get_possible(link);
 752         if (result)
 753                 goto end;
 754
 755         /* query and set link->irq.active */
 756         acpi_pci_link_get_current(link);
 757
 758         printk(PREFIX "%s [%s] (IRQs", acpi_device_name(device),
 759                acpi_device_bid(device));
 760         for (i = 0; i < link->irq.possible_count; i++) {
 761                 if (link->irq.active == link->irq.possible[i]) {
 762                         printk(" *%d", link->irq.possible[i]);
 763                         found = 1;
 764                 } else
 765                         printk(" %d", link->irq.possible[i]);
 766         }
 767
 768         printk(")");
 769
 770         if (!found)
 771                 printk(" *%d", link->irq.active);
 772
 773         if (!link->device->status.enabled)
 774                 printk(", disabled.");
 775
 776         printk("\n");
 777
 778         /* TBD: Acquire/release lock */
 779         list_add_tail(&link->node, &acpi_link.entries);
 780         acpi_link.count++;
 781
 782       end:
 783         /* disable all links -- to be activated on use */
 784         acpi_ut_evaluate_object(link->handle, "_DIS", 0, NULL);
 785         up(&acpi_link_lock);
 786
 787         if (result)
 788                 kfree(link);
 789
 790         return_VALUE(result);
 791 }
 792
 793 static int acpi_pci_link_resume(struct acpi_pci_link *link)
 794 {
 795         ACPI_FUNCTION_TRACE("acpi_pci_link_resume");
 796
 797         if (link->refcnt && link->irq.active && link->irq.initialized)
 798                 return_VALUE(acpi_pci_link_set(link, link->irq.active));
 799         else
 800                 return_VALUE(0);
 801 }
 802
 803 /*
 804  * FIXME: this is a workaround to avoid nasty warning.  It will be removed
 805  * after every device calls pci_disable_device in .resume.
 806  */
 807 int acpi_in_resume;
 808 static int irqrouter_resume(struct sys_device *dev)
 809 {
 810         struct list_head *node = NULL;
 811         struct acpi_pci_link *link = NULL;
 812
 813         ACPI_FUNCTION_TRACE("irqrouter_resume");
 814
 815         /* Make sure SCI is enabled again (Apple firmware bug?) */
 816         acpi_set_register(ACPI_BITREG_SCI_ENABLE, 1, ACPI_MTX_DO_NOT_LOCK);
 817
 818         acpi_in_resume = 1;
 819         list_for_each(node, &acpi_link.entries) {
 820                 link = list_entry(node, struct acpi_pci_link, node);
 821                 if (!link) {
 822                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
 823                                           "Invalid link context\n"));
 824                         continue;
 825                 }
 826                 acpi_pci_link_resume(link);
 827         }
 828         acpi_in_resume = 0;
 829         return_VALUE(0);
 830 }
 831
 832 static int acpi_pci_link_remove(struct acpi_device *device, int type)
 833 {
 834         struct acpi_pci_link *link = NULL;
 835
 836         ACPI_FUNCTION_TRACE("acpi_pci_link_remove");
 837
 838         if (!device || !acpi_driver_data(device))
 839                 return_VALUE(-EINVAL);
 840
 841         link = (struct acpi_pci_link *)acpi_driver_data(device);
 842
 843         down(&acpi_link_lock);
 844         list_del(&link->node);
 845         up(&acpi_link_lock);
 846
 847         kfree(link);
 848
 849         return_VALUE(0);
 850 }
 851
 852 /*
 853  * modify acpi_irq_penalty[] from cmdline
 854  */
 855 static int __init acpi_irq_penalty_update(char *str, int used)
 856 {
 857         int i;
 858
 859         for (i = 0; i < 16; i++) {
 860                 int retval;
 861                 int irq;
 862
 863                 retval = get_option(&str, &irq);
 864
 865                 if (!retval)
 866                         break;  /* no number found */
 867
 868                 if (irq < 0)
 869                         continue;
 870
 871                 if (irq >= ACPI_MAX_IRQS)
 872                         continue;
 873
 874                 if (used)
 875                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 876                 else
 877                         acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
 878
 879                 if (retval != 2)        /* no next number */
 880                         break;
 881         }
 882         return 1;
 883 }
 884
 885 /*
 886  * We'd like PNP to call this routine for the
 887  * single ISA_USED value for each legacy device.
 888  * But instead it calls us with each POSSIBLE setting.
 889  * There is no ISA_POSSIBLE weight, so we simply use
 890  * the (small) PCI_USING penalty.
 891  */
 892 void acpi_penalize_isa_irq(int irq, int active)
 893 {
 894         if (active)
 895                 acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
 896         else
 897                 acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
 898 }
 899
 900 /*
 901  * Over-ride default table to reserve additional IRQs for use by ISA
 902  * e.g. acpi_irq_isa=5
 903  * Useful for telling ACPI how not to interfere with your ISA sound card.
 904  */
 905 static int __init acpi_irq_isa(char *str)
 906 {
 907         return acpi_irq_penalty_update(str, 1);
 908 }
 909
 910 __setup("acpi_irq_isa=", acpi_irq_isa);
 911
 912 /*
 913  * Over-ride default table to free additional IRQs for use by PCI
 914  * e.g. acpi_irq_pci=7,15
 915  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
 916  */
 917 static int __init acpi_irq_pci(char *str)
 918 {
 919         return acpi_irq_penalty_update(str, 0);
 920 }
 921
 922 __setup("acpi_irq_pci=", acpi_irq_pci);
 923
 924 static int __init acpi_irq_nobalance_set(char *str)
 925 {
 926         acpi_irq_balance = 0;
 927         return 1;
 928 }
 929
 930 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
 931
 932 int __init acpi_irq_balance_set(char *str)
 933 {
 934         acpi_irq_balance = 1;
 935         return 1;
 936 }
 937
 938 __setup("acpi_irq_balance", acpi_irq_balance_set);
 939
 940 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
 941 static struct sysdev_class irqrouter_sysdev_class = {
 942         set_kset_name("irqrouter"),
 943         .resume = irqrouter_resume,
 944 };
 945
 946 static struct sys_device device_irqrouter = {
 947         .id = 0,
 948         .cls = &irqrouter_sysdev_class,
 949 };
 950
 951 static int __init irqrouter_init_sysfs(void)
 952 {
 953         int error;
 954
 955         ACPI_FUNCTION_TRACE("irqrouter_init_sysfs");
 956
 957         if (acpi_disabled || acpi_noirq)
 958                 return_VALUE(0);
 959
 960         error = sysdev_class_register(&irqrouter_sysdev_class);
 961         if (!error)
 962                 error = sysdev_register(&device_irqrouter);
 963
 964         return_VALUE(error);
 965 }
 966
 967 device_initcall(irqrouter_init_sysfs);
 968
 969 static int __init acpi_pci_link_init(void)
 970 {
 971         ACPI_FUNCTION_TRACE("acpi_pci_link_init");
 972
 973         if (acpi_noirq)
 974                 return_VALUE(0);
 975
 976         acpi_link.count = 0;
 977         INIT_LIST_HEAD(&acpi_link.entries);
 978
 979         if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
 980                 return_VALUE(-ENODEV);
 981
 982         return_VALUE(0);
 983 }
 984
 985 subsys_initcall(acpi_pci_link_init);