Version:  2.0.40 2.2.26 2.4.37 2.6.39 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15

Linux/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  *  You should have received a copy of the GNU General Public License along
 21  *  with this program; if not, write to the Free Software Foundation, Inc.,
 22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 23  *
 24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 25  *
 26  * TBD: 
 27  *      1. Support more than one IRQ resource entry per link device (index).
 28  *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
 29  *         for IRQ management (e.g. start()->_SRS).
 30  */
 31 
 32 #include <linux/syscore_ops.h>
 33 #include <linux/kernel.h>
 34 #include <linux/module.h>
 35 #include <linux/init.h>
 36 #include <linux/types.h>
 37 #include <linux/spinlock.h>
 38 #include <linux/pm.h>
 39 #include <linux/pci.h>
 40 #include <linux/mutex.h>
 41 #include <linux/slab.h>
 42 #include <linux/acpi.h>
 43 
 44 #include "internal.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_DEVICE_NAME       "PCI Interrupt Link"
 50 #define ACPI_PCI_LINK_FILE_INFO         "info"
 51 #define ACPI_PCI_LINK_FILE_STATUS       "state"
 52 #define ACPI_PCI_LINK_MAX_POSSIBLE      16
 53 
 54 static int acpi_pci_link_add(struct acpi_device *device,
 55                              const struct acpi_device_id *not_used);
 56 static void acpi_pci_link_remove(struct acpi_device *device);
 57 
 58 static const struct acpi_device_id link_device_ids[] = {
 59         {"PNP0C0F", 0},
 60         {"", 0},
 61 };
 62 
 63 static struct acpi_scan_handler pci_link_handler = {
 64         .ids = link_device_ids,
 65         .attach = acpi_pci_link_add,
 66         .detach = acpi_pci_link_remove,
 67 };
 68 
 69 /*
 70  * If a link is initialized, we never change its active and initialized
 71  * later even the link is disable. Instead, we just repick the active irq
 72  */
 73 struct acpi_pci_link_irq {
 74         u8 active;              /* Current IRQ */
 75         u8 triggering;          /* All IRQs */
 76         u8 polarity;            /* All IRQs */
 77         u8 resource_type;
 78         u8 possible_count;
 79         u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
 80         u8 initialized:1;
 81         u8 reserved:7;
 82 };
 83 
 84 struct acpi_pci_link {
 85         struct list_head                list;
 86         struct acpi_device              *device;
 87         struct acpi_pci_link_irq        irq;
 88         int                             refcnt;
 89 };
 90 
 91 static LIST_HEAD(acpi_link_list);
 92 static DEFINE_MUTEX(acpi_link_lock);
 93 
 94 /* --------------------------------------------------------------------------
 95                             PCI Link Device Management
 96    -------------------------------------------------------------------------- */
 97 
 98 /*
 99  * set context (link) possible list from resource list
100  */
101 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
102                                                 void *context)
103 {
104         struct acpi_pci_link *link = context;
105         u32 i;
106 
107         switch (resource->type) {
108         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
109         case ACPI_RESOURCE_TYPE_END_TAG:
110                 return AE_OK;
111         case ACPI_RESOURCE_TYPE_IRQ:
112                 {
113                         struct acpi_resource_irq *p = &resource->data.irq;
114                         if (!p || !p->interrupt_count) {
115                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
116                                                   "Blank _PRS IRQ resource\n"));
117                                 return AE_OK;
118                         }
119                         for (i = 0;
120                              (i < p->interrupt_count
121                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
122                                 if (!p->interrupts[i]) {
123                                         printk(KERN_WARNING PREFIX
124                                                "Invalid _PRS 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 _PRS 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
150                                                "Invalid _PRS IRQ %d\n",
151                                                p->interrupts[i]);
152                                         continue;
153                                 }
154                                 link->irq.possible[i] = p->interrupts[i];
155                                 link->irq.possible_count++;
156                         }
157                         link->irq.triggering = p->triggering;
158                         link->irq.polarity = p->polarity;
159                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
160                         break;
161                 }
162         default:
163                 printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
164                        resource->type);
165                 return AE_OK;
166         }
167 
168         return AE_CTRL_TERMINATE;
169 }
170 
171 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
172 {
173         acpi_status status;
174 
175         status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
176                                      acpi_pci_link_check_possible, link);
177         if (ACPI_FAILURE(status)) {
178                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
179                 return -ENODEV;
180         }
181 
182         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
183                           "Found %d possible IRQs\n",
184                           link->irq.possible_count));
185 
186         return 0;
187 }
188 
189 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
190                                                void *context)
191 {
192         int *irq = context;
193 
194         switch (resource->type) {
195         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
196         case ACPI_RESOURCE_TYPE_END_TAG:
197                 return AE_OK;
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 _CRS 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 _CRS 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 "_CRS resource type 0x%x isn't an IRQ\n",
232                        resource->type);
233                 return AE_OK;
234         }
235 
236         return AE_CTRL_TERMINATE;
237 }
238 
239 /*
240  * Run _CRS and set link->irq.active
241  *
242  * return value:
243  * 0 - success
244  * !0 - failure
245  */
246 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
247 {
248         int result = 0;
249         acpi_status status;
250         int irq = 0;
251 
252         link->irq.active = 0;
253 
254         /* in practice, status disabled is meaningless, ignore it */
255         if (acpi_strict) {
256                 /* Query _STA, set link->device->status */
257                 result = acpi_bus_get_status(link->device);
258                 if (result) {
259                         printk(KERN_ERR PREFIX "Unable to read status\n");
260                         goto end;
261                 }
262 
263                 if (!link->device->status.enabled) {
264                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
265                         return 0;
266                 }
267         }
268 
269         /* 
270          * Query and parse _CRS to get the current IRQ assignment. 
271          */
272 
273         status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
274                                      acpi_pci_link_check_current, &irq);
275         if (ACPI_FAILURE(status)) {
276                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
277                 result = -ENODEV;
278                 goto end;
279         }
280 
281         if (acpi_strict && !irq) {
282                 printk(KERN_ERR PREFIX "_CRS returned 0\n");
283                 result = -ENODEV;
284         }
285 
286         link->irq.active = irq;
287 
288         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
289 
290       end:
291         return result;
292 }
293 
294 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
295 {
296         int result;
297         acpi_status status;
298         struct {
299                 struct acpi_resource res;
300                 struct acpi_resource end;
301         } *resource;
302         struct acpi_buffer buffer = { 0, NULL };
303 
304         if (!irq)
305                 return -EINVAL;
306 
307         resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
308         if (!resource)
309                 return -ENOMEM;
310 
311         buffer.length = sizeof(*resource) + 1;
312         buffer.pointer = resource;
313 
314         switch (link->irq.resource_type) {
315         case ACPI_RESOURCE_TYPE_IRQ:
316                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
317                 resource->res.length = sizeof(struct acpi_resource);
318                 resource->res.data.irq.triggering = link->irq.triggering;
319                 resource->res.data.irq.polarity =
320                     link->irq.polarity;
321                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
322                         resource->res.data.irq.sharable =
323                             ACPI_EXCLUSIVE;
324                 else
325                         resource->res.data.irq.sharable = ACPI_SHARED;
326                 resource->res.data.irq.interrupt_count = 1;
327                 resource->res.data.irq.interrupts[0] = irq;
328                 break;
329 
330         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
331                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
332                 resource->res.length = sizeof(struct acpi_resource);
333                 resource->res.data.extended_irq.producer_consumer =
334                     ACPI_CONSUMER;
335                 resource->res.data.extended_irq.triggering =
336                     link->irq.triggering;
337                 resource->res.data.extended_irq.polarity =
338                     link->irq.polarity;
339                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
340                         resource->res.data.irq.sharable =
341                             ACPI_EXCLUSIVE;
342                 else
343                         resource->res.data.irq.sharable = ACPI_SHARED;
344                 resource->res.data.extended_irq.interrupt_count = 1;
345                 resource->res.data.extended_irq.interrupts[0] = irq;
346                 /* ignore resource_source, it's optional */
347                 break;
348         default:
349                 printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
350                 result = -EINVAL;
351                 goto end;
352 
353         }
354         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
355         resource->end.length = sizeof(struct acpi_resource);
356 
357         /* Attempt to set the resource */
358         status = acpi_set_current_resources(link->device->handle, &buffer);
359 
360         /* check for total failure */
361         if (ACPI_FAILURE(status)) {
362                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
363                 result = -ENODEV;
364                 goto end;
365         }
366 
367         /* Query _STA, set device->status */
368         result = acpi_bus_get_status(link->device);
369         if (result) {
370                 printk(KERN_ERR PREFIX "Unable to read status\n");
371                 goto end;
372         }
373         if (!link->device->status.enabled) {
374                 printk(KERN_WARNING PREFIX
375                               "%s [%s] disabled and referenced, BIOS bug\n",
376                               acpi_device_name(link->device),
377                               acpi_device_bid(link->device));
378         }
379 
380         /* Query _CRS, set link->irq.active */
381         result = acpi_pci_link_get_current(link);
382         if (result) {
383                 goto end;
384         }
385 
386         /*
387          * Is current setting not what we set?
388          * set link->irq.active
389          */
390         if (link->irq.active != irq) {
391                 /*
392                  * policy: when _CRS doesn't return what we just _SRS
393                  * assume _SRS worked and override _CRS value.
394                  */
395                 printk(KERN_WARNING PREFIX
396                               "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
397                               acpi_device_name(link->device),
398                               acpi_device_bid(link->device), link->irq.active, irq);
399                 link->irq.active = irq;
400         }
401 
402         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
403 
404       end:
405         kfree(resource);
406         return result;
407 }
408 
409 /* --------------------------------------------------------------------------
410                             PCI Link IRQ Management
411    -------------------------------------------------------------------------- */
412 
413 /*
414  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
415  * Link Devices to move the PIRQs around to minimize sharing.
416  * 
417  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
418  * that the BIOS has already set to active.  This is necessary because
419  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
420  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
421  * even if acpi_irq_nobalance is set.
422  *
423  * A tables of penalties avoids directing PCI interrupts to well known
424  * ISA IRQs. Boot params are available to over-ride the default table:
425  *
426  * List interrupts that are free for PCI use.
427  * acpi_irq_pci=n[,m]
428  *
429  * List interrupts that should not be used for PCI:
430  * acpi_irq_isa=n[,m]
431  *
432  * Note that PCI IRQ routers have a list of possible IRQs,
433  * which may not include the IRQs this table says are available.
434  * 
435  * Since this heuristic can't tell the difference between a link
436  * that no device will attach to, vs. a link which may be shared
437  * by multiple active devices -- it is not optimal.
438  *
439  * If interrupt performance is that important, get an IO-APIC system
440  * with a pin dedicated to each device.  Or for that matter, an MSI
441  * enabled system.
442  */
443 
444 #define ACPI_MAX_IRQS           256
445 #define ACPI_MAX_ISA_IRQ        16
446 
447 #define PIRQ_PENALTY_PCI_AVAILABLE      (0)
448 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
449 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
450 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
451 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
452 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
453 
454 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
455         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
456         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
457         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
458         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
459         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
460         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
461         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
462         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
463         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
464         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ9  PCI, often acpi */
465         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ10 PCI */
466         PIRQ_PENALTY_PCI_AVAILABLE,     /* IRQ11 PCI */
467         PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
468         PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
469         PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
470         PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
471         /* >IRQ15 */
472 };
473 
474 int __init acpi_irq_penalty_init(void)
475 {
476         struct acpi_pci_link *link;
477         int i;
478 
479         /*
480          * Update penalties to facilitate IRQ balancing.
481          */
482         list_for_each_entry(link, &acpi_link_list, list) {
483 
484                 /*
485                  * reflect the possible and active irqs in the penalty table --
486                  * useful for breaking ties.
487                  */
488                 if (link->irq.possible_count) {
489                         int penalty =
490                             PIRQ_PENALTY_PCI_POSSIBLE /
491                             link->irq.possible_count;
492 
493                         for (i = 0; i < link->irq.possible_count; i++) {
494                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
495                                         acpi_irq_penalty[link->irq.
496                                                          possible[i]] +=
497                                             penalty;
498                         }
499 
500                 } else if (link->irq.active) {
501                         acpi_irq_penalty[link->irq.active] +=
502                             PIRQ_PENALTY_PCI_POSSIBLE;
503                 }
504         }
505         /* Add a penalty for the SCI */
506         acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
507         return 0;
508 }
509 
510 static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
511 
512 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
513 {
514         int irq;
515         int i;
516 
517         if (link->irq.initialized) {
518                 if (link->refcnt == 0)
519                         /* This means the link is disabled but initialized */
520                         acpi_pci_link_set(link, link->irq.active);
521                 return 0;
522         }
523 
524         /*
525          * search for active IRQ in list of possible IRQs.
526          */
527         for (i = 0; i < link->irq.possible_count; ++i) {
528                 if (link->irq.active == link->irq.possible[i])
529                         break;
530         }
531         /*
532          * forget active IRQ that is not in possible list
533          */
534         if (i == link->irq.possible_count) {
535                 if (acpi_strict)
536                         printk(KERN_WARNING PREFIX "_CRS %d not found"
537                                       " in _PRS\n", link->irq.active);
538                 link->irq.active = 0;
539         }
540 
541         /*
542          * if active found, use it; else pick entry from end of possible list.
543          */
544         if (link->irq.active)
545                 irq = link->irq.active;
546         else
547                 irq = link->irq.possible[link->irq.possible_count - 1];
548 
549         if (acpi_irq_balance || !link->irq.active) {
550                 /*
551                  * Select the best IRQ.  This is done in reverse to promote
552                  * the use of IRQs 9, 10, 11, and >15.
553                  */
554                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
555                         if (acpi_irq_penalty[irq] >
556                             acpi_irq_penalty[link->irq.possible[i]])
557                                 irq = link->irq.possible[i];
558                 }
559         }
560 
561         /* Attempt to enable the link device at this IRQ. */
562         if (acpi_pci_link_set(link, irq)) {
563                 printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
564                             "Try pci=noacpi or acpi=off\n",
565                             acpi_device_name(link->device),
566                             acpi_device_bid(link->device));
567                 return -ENODEV;
568         } else {
569                 acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
570                 printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
571                        acpi_device_name(link->device),
572                        acpi_device_bid(link->device), link->irq.active);
573         }
574 
575         link->irq.initialized = 1;
576         return 0;
577 }
578 
579 /*
580  * acpi_pci_link_allocate_irq
581  * success: return IRQ >= 0
582  * failure: return -1
583  */
584 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
585                                int *polarity, char **name)
586 {
587         int result;
588         struct acpi_device *device;
589         struct acpi_pci_link *link;
590 
591         result = acpi_bus_get_device(handle, &device);
592         if (result) {
593                 printk(KERN_ERR PREFIX "Invalid link device\n");
594                 return -1;
595         }
596 
597         link = acpi_driver_data(device);
598         if (!link) {
599                 printk(KERN_ERR PREFIX "Invalid link context\n");
600                 return -1;
601         }
602 
603         /* TBD: Support multiple index (IRQ) entries per Link Device */
604         if (index) {
605                 printk(KERN_ERR PREFIX "Invalid index %d\n", index);
606                 return -1;
607         }
608 
609         mutex_lock(&acpi_link_lock);
610         if (acpi_pci_link_allocate(link)) {
611                 mutex_unlock(&acpi_link_lock);
612                 return -1;
613         }
614 
615         if (!link->irq.active) {
616                 mutex_unlock(&acpi_link_lock);
617                 printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
618                 return -1;
619         }
620         link->refcnt++;
621         mutex_unlock(&acpi_link_lock);
622 
623         if (triggering)
624                 *triggering = link->irq.triggering;
625         if (polarity)
626                 *polarity = link->irq.polarity;
627         if (name)
628                 *name = acpi_device_bid(link->device);
629         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
630                           "Link %s is referenced\n",
631                           acpi_device_bid(link->device)));
632         return (link->irq.active);
633 }
634 
635 /*
636  * We don't change link's irq information here.  After it is reenabled, we
637  * continue use the info
638  */
639 int acpi_pci_link_free_irq(acpi_handle handle)
640 {
641         struct acpi_device *device;
642         struct acpi_pci_link *link;
643         acpi_status result;
644 
645         result = acpi_bus_get_device(handle, &device);
646         if (result) {
647                 printk(KERN_ERR PREFIX "Invalid link device\n");
648                 return -1;
649         }
650 
651         link = acpi_driver_data(device);
652         if (!link) {
653                 printk(KERN_ERR PREFIX "Invalid link context\n");
654                 return -1;
655         }
656 
657         mutex_lock(&acpi_link_lock);
658         if (!link->irq.initialized) {
659                 mutex_unlock(&acpi_link_lock);
660                 printk(KERN_ERR PREFIX "Link isn't initialized\n");
661                 return -1;
662         }
663 #ifdef  FUTURE_USE
664         /*
665          * The Link reference count allows us to _DISable an unused link
666          * and suspend time, and set it again  on resume.
667          * However, 2.6.12 still has irq_router.resume
668          * which blindly restores the link state.
669          * So we disable the reference count method
670          * to prevent duplicate acpi_pci_link_set()
671          * which would harm some systems
672          */
673         link->refcnt--;
674 #endif
675         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
676                           "Link %s is dereferenced\n",
677                           acpi_device_bid(link->device)));
678 
679         if (link->refcnt == 0)
680                 acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
681 
682         mutex_unlock(&acpi_link_lock);
683         return (link->irq.active);
684 }
685 
686 /* --------------------------------------------------------------------------
687                                  Driver Interface
688    -------------------------------------------------------------------------- */
689 
690 static int acpi_pci_link_add(struct acpi_device *device,
691                              const struct acpi_device_id *not_used)
692 {
693         int result;
694         struct acpi_pci_link *link;
695         int i;
696         int found = 0;
697 
698         link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
699         if (!link)
700                 return -ENOMEM;
701 
702         link->device = device;
703         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
704         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
705         device->driver_data = link;
706 
707         mutex_lock(&acpi_link_lock);
708         result = acpi_pci_link_get_possible(link);
709         if (result)
710                 goto end;
711 
712         /* query and set link->irq.active */
713         acpi_pci_link_get_current(link);
714 
715         printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
716                acpi_device_bid(device));
717         for (i = 0; i < link->irq.possible_count; i++) {
718                 if (link->irq.active == link->irq.possible[i]) {
719                         printk(KERN_CONT " *%d", link->irq.possible[i]);
720                         found = 1;
721                 } else
722                         printk(KERN_CONT " %d", link->irq.possible[i]);
723         }
724 
725         printk(KERN_CONT ")");
726 
727         if (!found)
728                 printk(KERN_CONT " *%d", link->irq.active);
729 
730         if (!link->device->status.enabled)
731                 printk(KERN_CONT ", disabled.");
732 
733         printk(KERN_CONT "\n");
734 
735         list_add_tail(&link->list, &acpi_link_list);
736 
737       end:
738         /* disable all links -- to be activated on use */
739         acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
740         mutex_unlock(&acpi_link_lock);
741 
742         if (result)
743                 kfree(link);
744 
745         return result < 0 ? result : 1;
746 }
747 
748 static int acpi_pci_link_resume(struct acpi_pci_link *link)
749 {
750         if (link->refcnt && link->irq.active && link->irq.initialized)
751                 return (acpi_pci_link_set(link, link->irq.active));
752 
753         return 0;
754 }
755 
756 static void irqrouter_resume(void)
757 {
758         struct acpi_pci_link *link;
759 
760         list_for_each_entry(link, &acpi_link_list, list) {
761                 acpi_pci_link_resume(link);
762         }
763 }
764 
765 static void acpi_pci_link_remove(struct acpi_device *device)
766 {
767         struct acpi_pci_link *link;
768 
769         link = acpi_driver_data(device);
770 
771         mutex_lock(&acpi_link_lock);
772         list_del(&link->list);
773         mutex_unlock(&acpi_link_lock);
774 
775         kfree(link);
776 }
777 
778 /*
779  * modify acpi_irq_penalty[] from cmdline
780  */
781 static int __init acpi_irq_penalty_update(char *str, int used)
782 {
783         int i;
784 
785         for (i = 0; i < 16; i++) {
786                 int retval;
787                 int irq;
788 
789                 retval = get_option(&str, &irq);
790 
791                 if (!retval)
792                         break;  /* no number found */
793 
794                 if (irq < 0)
795                         continue;
796 
797                 if (irq >= ARRAY_SIZE(acpi_irq_penalty))
798                         continue;
799 
800                 if (used)
801                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
802                 else
803                         acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
804 
805                 if (retval != 2)        /* no next number */
806                         break;
807         }
808         return 1;
809 }
810 
811 /*
812  * We'd like PNP to call this routine for the
813  * single ISA_USED value for each legacy device.
814  * But instead it calls us with each POSSIBLE setting.
815  * There is no ISA_POSSIBLE weight, so we simply use
816  * the (small) PCI_USING penalty.
817  */
818 void acpi_penalize_isa_irq(int irq, int active)
819 {
820         if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
821                 if (active)
822                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
823                 else
824                         acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
825         }
826 }
827 
828 /*
829  * Over-ride default table to reserve additional IRQs for use by ISA
830  * e.g. acpi_irq_isa=5
831  * Useful for telling ACPI how not to interfere with your ISA sound card.
832  */
833 static int __init acpi_irq_isa(char *str)
834 {
835         return acpi_irq_penalty_update(str, 1);
836 }
837 
838 __setup("acpi_irq_isa=", acpi_irq_isa);
839 
840 /*
841  * Over-ride default table to free additional IRQs for use by PCI
842  * e.g. acpi_irq_pci=7,15
843  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
844  */
845 static int __init acpi_irq_pci(char *str)
846 {
847         return acpi_irq_penalty_update(str, 0);
848 }
849 
850 __setup("acpi_irq_pci=", acpi_irq_pci);
851 
852 static int __init acpi_irq_nobalance_set(char *str)
853 {
854         acpi_irq_balance = 0;
855         return 1;
856 }
857 
858 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
859 
860 static int __init acpi_irq_balance_set(char *str)
861 {
862         acpi_irq_balance = 1;
863         return 1;
864 }
865 
866 __setup("acpi_irq_balance", acpi_irq_balance_set);
867 
868 static struct syscore_ops irqrouter_syscore_ops = {
869         .resume = irqrouter_resume,
870 };
871 
872 void __init acpi_pci_link_init(void)
873 {
874         if (acpi_noirq)
875                 return;
876 
877         if (acpi_irq_balance == -1) {
878                 /* no command line switch: enable balancing in IOAPIC mode */
879                 if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
880                         acpi_irq_balance = 1;
881                 else
882                         acpi_irq_balance = 0;
883         }
884         register_syscore_ops(&irqrouter_syscore_ops);
885         acpi_scan_add_handler(&pci_link_handler);
886 }
887 

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