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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  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 21  *
 22  * TBD: 
 23  *      1. Support more than one IRQ resource entry per link device (index).
 24  *      2. Implement start/stop mechanism and use ACPI Bus Driver facilities
 25  *         for IRQ management (e.g. start()->_SRS).
 26  */
 27 
 28 #include <linux/syscore_ops.h>
 29 #include <linux/kernel.h>
 30 #include <linux/module.h>
 31 #include <linux/init.h>
 32 #include <linux/types.h>
 33 #include <linux/spinlock.h>
 34 #include <linux/pm.h>
 35 #include <linux/pci.h>
 36 #include <linux/mutex.h>
 37 #include <linux/slab.h>
 38 #include <linux/acpi.h>
 39 #include <linux/irq.h>
 40 
 41 #include "internal.h"
 42 
 43 #define _COMPONENT                      ACPI_PCI_COMPONENT
 44 ACPI_MODULE_NAME("pci_link");
 45 #define ACPI_PCI_LINK_CLASS             "pci_irq_routing"
 46 #define ACPI_PCI_LINK_DEVICE_NAME       "PCI Interrupt Link"
 47 #define ACPI_PCI_LINK_FILE_INFO         "info"
 48 #define ACPI_PCI_LINK_FILE_STATUS       "state"
 49 #define ACPI_PCI_LINK_MAX_POSSIBLE      16
 50 
 51 static int acpi_pci_link_add(struct acpi_device *device,
 52                              const struct acpi_device_id *not_used);
 53 static void acpi_pci_link_remove(struct acpi_device *device);
 54 
 55 static const struct acpi_device_id link_device_ids[] = {
 56         {"PNP0C0F", 0},
 57         {"", 0},
 58 };
 59 
 60 static struct acpi_scan_handler pci_link_handler = {
 61         .ids = link_device_ids,
 62         .attach = acpi_pci_link_add,
 63         .detach = acpi_pci_link_remove,
 64 };
 65 
 66 /*
 67  * If a link is initialized, we never change its active and initialized
 68  * later even the link is disable. Instead, we just repick the active irq
 69  */
 70 struct acpi_pci_link_irq {
 71         u32 active;             /* Current IRQ */
 72         u8 triggering;          /* All IRQs */
 73         u8 polarity;            /* All IRQs */
 74         u8 resource_type;
 75         u8 possible_count;
 76         u32 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
 77         u8 initialized:1;
 78         u8 reserved:7;
 79 };
 80 
 81 struct acpi_pci_link {
 82         struct list_head                list;
 83         struct acpi_device              *device;
 84         struct acpi_pci_link_irq        irq;
 85         int                             refcnt;
 86 };
 87 
 88 static LIST_HEAD(acpi_link_list);
 89 static DEFINE_MUTEX(acpi_link_lock);
 90 static int sci_irq = -1, sci_penalty;
 91 
 92 /* --------------------------------------------------------------------------
 93                             PCI Link Device Management
 94    -------------------------------------------------------------------------- */
 95 
 96 /*
 97  * set context (link) possible list from resource list
 98  */
 99 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
100                                                 void *context)
101 {
102         struct acpi_pci_link *link = context;
103         u32 i;
104 
105         switch (resource->type) {
106         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
107         case ACPI_RESOURCE_TYPE_END_TAG:
108                 return AE_OK;
109         case ACPI_RESOURCE_TYPE_IRQ:
110                 {
111                         struct acpi_resource_irq *p = &resource->data.irq;
112                         if (!p || !p->interrupt_count) {
113                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
114                                                   "Blank _PRS IRQ resource\n"));
115                                 return AE_OK;
116                         }
117                         for (i = 0;
118                              (i < p->interrupt_count
119                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
120                                 if (!p->interrupts[i]) {
121                                         printk(KERN_WARNING PREFIX
122                                                "Invalid _PRS IRQ %d\n",
123                                                p->interrupts[i]);
124                                         continue;
125                                 }
126                                 link->irq.possible[i] = p->interrupts[i];
127                                 link->irq.possible_count++;
128                         }
129                         link->irq.triggering = p->triggering;
130                         link->irq.polarity = p->polarity;
131                         link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
132                         break;
133                 }
134         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
135                 {
136                         struct acpi_resource_extended_irq *p =
137                             &resource->data.extended_irq;
138                         if (!p || !p->interrupt_count) {
139                                 printk(KERN_WARNING PREFIX
140                                               "Blank _PRS EXT IRQ resource\n");
141                                 return AE_OK;
142                         }
143                         for (i = 0;
144                              (i < p->interrupt_count
145                               && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
146                                 if (!p->interrupts[i]) {
147                                         printk(KERN_WARNING PREFIX
148                                                "Invalid _PRS IRQ %d\n",
149                                                p->interrupts[i]);
150                                         continue;
151                                 }
152                                 link->irq.possible[i] = p->interrupts[i];
153                                 link->irq.possible_count++;
154                         }
155                         link->irq.triggering = p->triggering;
156                         link->irq.polarity = p->polarity;
157                         link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
158                         break;
159                 }
160         default:
161                 printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
162                        resource->type);
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         status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
174                                      acpi_pci_link_check_possible, link);
175         if (ACPI_FAILURE(status)) {
176                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
177                 return -ENODEV;
178         }
179 
180         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
181                           "Found %d possible IRQs\n",
182                           link->irq.possible_count));
183 
184         return 0;
185 }
186 
187 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
188                                                void *context)
189 {
190         int *irq = context;
191 
192         switch (resource->type) {
193         case ACPI_RESOURCE_TYPE_START_DEPENDENT:
194         case ACPI_RESOURCE_TYPE_END_TAG:
195                 return AE_OK;
196         case ACPI_RESOURCE_TYPE_IRQ:
197                 {
198                         struct acpi_resource_irq *p = &resource->data.irq;
199                         if (!p || !p->interrupt_count) {
200                                 /*
201                                  * IRQ descriptors may have no IRQ# bits set,
202                                  * particularly those those w/ _STA disabled
203                                  */
204                                 ACPI_DEBUG_PRINT((ACPI_DB_INFO,
205                                                   "Blank _CRS IRQ resource\n"));
206                                 return AE_OK;
207                         }
208                         *irq = p->interrupts[0];
209                         break;
210                 }
211         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
212                 {
213                         struct acpi_resource_extended_irq *p =
214                             &resource->data.extended_irq;
215                         if (!p || !p->interrupt_count) {
216                                 /*
217                                  * extended IRQ descriptors must
218                                  * return at least 1 IRQ
219                                  */
220                                 printk(KERN_WARNING PREFIX
221                                               "Blank _CRS EXT IRQ resource\n");
222                                 return AE_OK;
223                         }
224                         *irq = p->interrupts[0];
225                         break;
226                 }
227                 break;
228         default:
229                 printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
230                        resource->type);
231                 return AE_OK;
232         }
233 
234         return AE_CTRL_TERMINATE;
235 }
236 
237 /*
238  * Run _CRS and set link->irq.active
239  *
240  * return value:
241  * 0 - success
242  * !0 - failure
243  */
244 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
245 {
246         int result = 0;
247         acpi_status status;
248         int irq = 0;
249 
250         link->irq.active = 0;
251 
252         /* in practice, status disabled is meaningless, ignore it */
253         if (acpi_strict) {
254                 /* Query _STA, set link->device->status */
255                 result = acpi_bus_get_status(link->device);
256                 if (result) {
257                         printk(KERN_ERR PREFIX "Unable to read status\n");
258                         goto end;
259                 }
260 
261                 if (!link->device->status.enabled) {
262                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
263                         return 0;
264                 }
265         }
266 
267         /* 
268          * Query and parse _CRS to get the current IRQ assignment. 
269          */
270 
271         status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
272                                      acpi_pci_link_check_current, &irq);
273         if (ACPI_FAILURE(status)) {
274                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
275                 result = -ENODEV;
276                 goto end;
277         }
278 
279         if (acpi_strict && !irq) {
280                 printk(KERN_ERR PREFIX "_CRS returned 0\n");
281                 result = -ENODEV;
282         }
283 
284         link->irq.active = irq;
285 
286         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
287 
288       end:
289         return result;
290 }
291 
292 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
293 {
294         int result;
295         acpi_status status;
296         struct {
297                 struct acpi_resource res;
298                 struct acpi_resource end;
299         } *resource;
300         struct acpi_buffer buffer = { 0, NULL };
301 
302         if (!irq)
303                 return -EINVAL;
304 
305         resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
306         if (!resource)
307                 return -ENOMEM;
308 
309         buffer.length = sizeof(*resource) + 1;
310         buffer.pointer = resource;
311 
312         switch (link->irq.resource_type) {
313         case ACPI_RESOURCE_TYPE_IRQ:
314                 resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
315                 resource->res.length = sizeof(struct acpi_resource);
316                 resource->res.data.irq.triggering = link->irq.triggering;
317                 resource->res.data.irq.polarity =
318                     link->irq.polarity;
319                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
320                         resource->res.data.irq.sharable =
321                             ACPI_EXCLUSIVE;
322                 else
323                         resource->res.data.irq.sharable = ACPI_SHARED;
324                 resource->res.data.irq.interrupt_count = 1;
325                 resource->res.data.irq.interrupts[0] = irq;
326                 break;
327 
328         case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
329                 resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
330                 resource->res.length = sizeof(struct acpi_resource);
331                 resource->res.data.extended_irq.producer_consumer =
332                     ACPI_CONSUMER;
333                 resource->res.data.extended_irq.triggering =
334                     link->irq.triggering;
335                 resource->res.data.extended_irq.polarity =
336                     link->irq.polarity;
337                 if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
338                         resource->res.data.irq.sharable =
339                             ACPI_EXCLUSIVE;
340                 else
341                         resource->res.data.irq.sharable = ACPI_SHARED;
342                 resource->res.data.extended_irq.interrupt_count = 1;
343                 resource->res.data.extended_irq.interrupts[0] = irq;
344                 /* ignore resource_source, it's optional */
345                 break;
346         default:
347                 printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
348                 result = -EINVAL;
349                 goto end;
350 
351         }
352         resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
353         resource->end.length = sizeof(struct acpi_resource);
354 
355         /* Attempt to set the resource */
356         status = acpi_set_current_resources(link->device->handle, &buffer);
357 
358         /* check for total failure */
359         if (ACPI_FAILURE(status)) {
360                 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
361                 result = -ENODEV;
362                 goto end;
363         }
364 
365         /* Query _STA, set device->status */
366         result = acpi_bus_get_status(link->device);
367         if (result) {
368                 printk(KERN_ERR PREFIX "Unable to read status\n");
369                 goto end;
370         }
371         if (!link->device->status.enabled) {
372                 printk(KERN_WARNING PREFIX
373                               "%s [%s] disabled and referenced, BIOS bug\n",
374                               acpi_device_name(link->device),
375                               acpi_device_bid(link->device));
376         }
377 
378         /* Query _CRS, set link->irq.active */
379         result = acpi_pci_link_get_current(link);
380         if (result) {
381                 goto end;
382         }
383 
384         /*
385          * Is current setting not what we set?
386          * set link->irq.active
387          */
388         if (link->irq.active != irq) {
389                 /*
390                  * policy: when _CRS doesn't return what we just _SRS
391                  * assume _SRS worked and override _CRS value.
392                  */
393                 printk(KERN_WARNING PREFIX
394                               "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
395                               acpi_device_name(link->device),
396                               acpi_device_bid(link->device), link->irq.active, irq);
397                 link->irq.active = irq;
398         }
399 
400         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
401 
402       end:
403         kfree(resource);
404         return result;
405 }
406 
407 /* --------------------------------------------------------------------------
408                             PCI Link IRQ Management
409    -------------------------------------------------------------------------- */
410 
411 /*
412  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
413  * Link Devices to move the PIRQs around to minimize sharing.
414  * 
415  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
416  * that the BIOS has already set to active.  This is necessary because
417  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
418  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
419  * even if acpi_irq_nobalance is set.
420  *
421  * A tables of penalties avoids directing PCI interrupts to well known
422  * ISA IRQs. Boot params are available to over-ride the default table:
423  *
424  * List interrupts that are free for PCI use.
425  * acpi_irq_pci=n[,m]
426  *
427  * List interrupts that should not be used for PCI:
428  * acpi_irq_isa=n[,m]
429  *
430  * Note that PCI IRQ routers have a list of possible IRQs,
431  * which may not include the IRQs this table says are available.
432  * 
433  * Since this heuristic can't tell the difference between a link
434  * that no device will attach to, vs. a link which may be shared
435  * by multiple active devices -- it is not optimal.
436  *
437  * If interrupt performance is that important, get an IO-APIC system
438  * with a pin dedicated to each device.  Or for that matter, an MSI
439  * enabled system.
440  */
441 
442 #define ACPI_MAX_ISA_IRQS       16
443 
444 #define PIRQ_PENALTY_PCI_POSSIBLE       (16*16)
445 #define PIRQ_PENALTY_PCI_USING          (16*16*16)
446 #define PIRQ_PENALTY_ISA_TYPICAL        (16*16*16*16)
447 #define PIRQ_PENALTY_ISA_USED           (16*16*16*16*16)
448 #define PIRQ_PENALTY_ISA_ALWAYS         (16*16*16*16*16*16)
449 
450 static int acpi_isa_irq_penalty[ACPI_MAX_ISA_IRQS] = {
451         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ0 timer */
452         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ1 keyboard */
453         PIRQ_PENALTY_ISA_ALWAYS,        /* IRQ2 cascade */
454         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ3 serial */
455         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ4 serial */
456         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ5 sometimes SoundBlaster */
457         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ6 */
458         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ7 parallel, spurious */
459         PIRQ_PENALTY_ISA_TYPICAL,       /* IRQ8 rtc, sometimes */
460         0,                              /* IRQ9  PCI, often acpi */
461         0,                              /* IRQ10 PCI */
462         0,                              /* IRQ11 PCI */
463         PIRQ_PENALTY_ISA_USED,          /* IRQ12 mouse */
464         PIRQ_PENALTY_ISA_USED,          /* IRQ13 fpe, sometimes */
465         PIRQ_PENALTY_ISA_USED,          /* IRQ14 ide0 */
466         PIRQ_PENALTY_ISA_USED,          /* IRQ15 ide1 */
467         /* >IRQ15 */
468 };
469 
470 static int acpi_irq_pci_sharing_penalty(int irq)
471 {
472         struct acpi_pci_link *link;
473         int penalty = 0;
474         int i;
475 
476         list_for_each_entry(link, &acpi_link_list, list) {
477                 /*
478                  * If a link is active, penalize its IRQ heavily
479                  * so we try to choose a different IRQ.
480                  */
481                 if (link->irq.active && link->irq.active == irq)
482                         penalty += PIRQ_PENALTY_PCI_USING;
483 
484                 /*
485                  * penalize the IRQs PCI might use, but not as severely.
486                  */
487                 for (i = 0; i < link->irq.possible_count; i++)
488                         if (link->irq.possible[i] == irq)
489                                 penalty += PIRQ_PENALTY_PCI_POSSIBLE /
490                                         link->irq.possible_count;
491         }
492 
493         return penalty;
494 }
495 
496 static int acpi_irq_get_penalty(int irq)
497 {
498         int penalty = 0;
499 
500         if (irq == sci_irq)
501                 penalty += sci_penalty;
502 
503         if (irq < ACPI_MAX_ISA_IRQS)
504                 return penalty + acpi_isa_irq_penalty[irq];
505 
506         return penalty + acpi_irq_pci_sharing_penalty(irq);
507 }
508 
509 int __init acpi_irq_penalty_init(void)
510 {
511         struct acpi_pci_link *link;
512         int i;
513 
514         /*
515          * Update penalties to facilitate IRQ balancing.
516          */
517         list_for_each_entry(link, &acpi_link_list, list) {
518 
519                 /*
520                  * reflect the possible and active irqs in the penalty table --
521                  * useful for breaking ties.
522                  */
523                 if (link->irq.possible_count) {
524                         int penalty =
525                             PIRQ_PENALTY_PCI_POSSIBLE /
526                             link->irq.possible_count;
527 
528                         for (i = 0; i < link->irq.possible_count; i++) {
529                                 if (link->irq.possible[i] < ACPI_MAX_ISA_IRQS)
530                                         acpi_isa_irq_penalty[link->irq.
531                                                          possible[i]] +=
532                                             penalty;
533                         }
534 
535                 } else if (link->irq.active &&
536                                 (link->irq.active < ACPI_MAX_ISA_IRQS)) {
537                         acpi_isa_irq_penalty[link->irq.active] +=
538                             PIRQ_PENALTY_PCI_POSSIBLE;
539                 }
540         }
541 
542         return 0;
543 }
544 
545 static int acpi_irq_balance = -1;       /* 0: static, 1: balance */
546 
547 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
548 {
549         int irq;
550         int i;
551 
552         if (link->irq.initialized) {
553                 if (link->refcnt == 0)
554                         /* This means the link is disabled but initialized */
555                         acpi_pci_link_set(link, link->irq.active);
556                 return 0;
557         }
558 
559         /*
560          * search for active IRQ in list of possible IRQs.
561          */
562         for (i = 0; i < link->irq.possible_count; ++i) {
563                 if (link->irq.active == link->irq.possible[i])
564                         break;
565         }
566         /*
567          * forget active IRQ that is not in possible list
568          */
569         if (i == link->irq.possible_count) {
570                 if (acpi_strict)
571                         printk(KERN_WARNING PREFIX "_CRS %d not found"
572                                       " in _PRS\n", link->irq.active);
573                 link->irq.active = 0;
574         }
575 
576         /*
577          * if active found, use it; else pick entry from end of possible list.
578          */
579         if (link->irq.active)
580                 irq = link->irq.active;
581         else
582                 irq = link->irq.possible[link->irq.possible_count - 1];
583 
584         if (acpi_irq_balance || !link->irq.active) {
585                 /*
586                  * Select the best IRQ.  This is done in reverse to promote
587                  * the use of IRQs 9, 10, 11, and >15.
588                  */
589                 for (i = (link->irq.possible_count - 1); i >= 0; i--) {
590                         if (acpi_irq_get_penalty(irq) >
591                             acpi_irq_get_penalty(link->irq.possible[i]))
592                                 irq = link->irq.possible[i];
593                 }
594         }
595         if (acpi_irq_get_penalty(irq) >= PIRQ_PENALTY_ISA_ALWAYS) {
596                 printk(KERN_ERR PREFIX "No IRQ available for %s [%s]. "
597                             "Try pci=noacpi or acpi=off\n",
598                             acpi_device_name(link->device),
599                             acpi_device_bid(link->device));
600                 return -ENODEV;
601         }
602 
603         /* Attempt to enable the link device at this IRQ. */
604         if (acpi_pci_link_set(link, irq)) {
605                 printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
606                             "Try pci=noacpi or acpi=off\n",
607                             acpi_device_name(link->device),
608                             acpi_device_bid(link->device));
609                 return -ENODEV;
610         } else {
611                 if (link->irq.active < ACPI_MAX_ISA_IRQS)
612                         acpi_isa_irq_penalty[link->irq.active] +=
613                                 PIRQ_PENALTY_PCI_USING;
614 
615                 printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
616                        acpi_device_name(link->device),
617                        acpi_device_bid(link->device), link->irq.active);
618         }
619 
620         link->irq.initialized = 1;
621         return 0;
622 }
623 
624 /*
625  * acpi_pci_link_allocate_irq
626  * success: return IRQ >= 0
627  * failure: return -1
628  */
629 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
630                                int *polarity, char **name)
631 {
632         int result;
633         struct acpi_device *device;
634         struct acpi_pci_link *link;
635 
636         result = acpi_bus_get_device(handle, &device);
637         if (result) {
638                 printk(KERN_ERR PREFIX "Invalid link device\n");
639                 return -1;
640         }
641 
642         link = acpi_driver_data(device);
643         if (!link) {
644                 printk(KERN_ERR PREFIX "Invalid link context\n");
645                 return -1;
646         }
647 
648         /* TBD: Support multiple index (IRQ) entries per Link Device */
649         if (index) {
650                 printk(KERN_ERR PREFIX "Invalid index %d\n", index);
651                 return -1;
652         }
653 
654         mutex_lock(&acpi_link_lock);
655         if (acpi_pci_link_allocate(link)) {
656                 mutex_unlock(&acpi_link_lock);
657                 return -1;
658         }
659 
660         if (!link->irq.active) {
661                 mutex_unlock(&acpi_link_lock);
662                 printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
663                 return -1;
664         }
665         link->refcnt++;
666         mutex_unlock(&acpi_link_lock);
667 
668         if (triggering)
669                 *triggering = link->irq.triggering;
670         if (polarity)
671                 *polarity = link->irq.polarity;
672         if (name)
673                 *name = acpi_device_bid(link->device);
674         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
675                           "Link %s is referenced\n",
676                           acpi_device_bid(link->device)));
677         return (link->irq.active);
678 }
679 
680 /*
681  * We don't change link's irq information here.  After it is reenabled, we
682  * continue use the info
683  */
684 int acpi_pci_link_free_irq(acpi_handle handle)
685 {
686         struct acpi_device *device;
687         struct acpi_pci_link *link;
688         acpi_status result;
689 
690         result = acpi_bus_get_device(handle, &device);
691         if (result) {
692                 printk(KERN_ERR PREFIX "Invalid link device\n");
693                 return -1;
694         }
695 
696         link = acpi_driver_data(device);
697         if (!link) {
698                 printk(KERN_ERR PREFIX "Invalid link context\n");
699                 return -1;
700         }
701 
702         mutex_lock(&acpi_link_lock);
703         if (!link->irq.initialized) {
704                 mutex_unlock(&acpi_link_lock);
705                 printk(KERN_ERR PREFIX "Link isn't initialized\n");
706                 return -1;
707         }
708 #ifdef  FUTURE_USE
709         /*
710          * The Link reference count allows us to _DISable an unused link
711          * and suspend time, and set it again  on resume.
712          * However, 2.6.12 still has irq_router.resume
713          * which blindly restores the link state.
714          * So we disable the reference count method
715          * to prevent duplicate acpi_pci_link_set()
716          * which would harm some systems
717          */
718         link->refcnt--;
719 #endif
720         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
721                           "Link %s is dereferenced\n",
722                           acpi_device_bid(link->device)));
723 
724         if (link->refcnt == 0)
725                 acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
726 
727         mutex_unlock(&acpi_link_lock);
728         return (link->irq.active);
729 }
730 
731 /* --------------------------------------------------------------------------
732                                  Driver Interface
733    -------------------------------------------------------------------------- */
734 
735 static int acpi_pci_link_add(struct acpi_device *device,
736                              const struct acpi_device_id *not_used)
737 {
738         int result;
739         struct acpi_pci_link *link;
740         int i;
741         int found = 0;
742 
743         link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
744         if (!link)
745                 return -ENOMEM;
746 
747         link->device = device;
748         strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
749         strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
750         device->driver_data = link;
751 
752         mutex_lock(&acpi_link_lock);
753         result = acpi_pci_link_get_possible(link);
754         if (result)
755                 goto end;
756 
757         /* query and set link->irq.active */
758         acpi_pci_link_get_current(link);
759 
760         printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
761                acpi_device_bid(device));
762         for (i = 0; i < link->irq.possible_count; i++) {
763                 if (link->irq.active == link->irq.possible[i]) {
764                         printk(KERN_CONT " *%d", link->irq.possible[i]);
765                         found = 1;
766                 } else
767                         printk(KERN_CONT " %d", link->irq.possible[i]);
768         }
769 
770         printk(KERN_CONT ")");
771 
772         if (!found)
773                 printk(KERN_CONT " *%d", link->irq.active);
774 
775         if (!link->device->status.enabled)
776                 printk(KERN_CONT ", disabled.");
777 
778         printk(KERN_CONT "\n");
779 
780         list_add_tail(&link->list, &acpi_link_list);
781 
782       end:
783         /* disable all links -- to be activated on use */
784         acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
785         mutex_unlock(&acpi_link_lock);
786 
787         if (result)
788                 kfree(link);
789 
790         return result < 0 ? result : 1;
791 }
792 
793 static int acpi_pci_link_resume(struct acpi_pci_link *link)
794 {
795         if (link->refcnt && link->irq.active && link->irq.initialized)
796                 return (acpi_pci_link_set(link, link->irq.active));
797 
798         return 0;
799 }
800 
801 static void irqrouter_resume(void)
802 {
803         struct acpi_pci_link *link;
804 
805         list_for_each_entry(link, &acpi_link_list, list) {
806                 acpi_pci_link_resume(link);
807         }
808 }
809 
810 static void acpi_pci_link_remove(struct acpi_device *device)
811 {
812         struct acpi_pci_link *link;
813 
814         link = acpi_driver_data(device);
815 
816         mutex_lock(&acpi_link_lock);
817         list_del(&link->list);
818         mutex_unlock(&acpi_link_lock);
819 
820         kfree(link);
821 }
822 
823 /*
824  * modify acpi_isa_irq_penalty[] from cmdline
825  */
826 static int __init acpi_irq_penalty_update(char *str, int used)
827 {
828         int i;
829 
830         for (i = 0; i < 16; i++) {
831                 int retval;
832                 int irq;
833                 int new_penalty;
834 
835                 retval = get_option(&str, &irq);
836 
837                 if (!retval)
838                         break;  /* no number found */
839 
840                 /* see if this is a ISA IRQ */
841                 if ((irq < 0) || (irq >= ACPI_MAX_ISA_IRQS))
842                         continue;
843 
844                 if (used)
845                         new_penalty = acpi_isa_irq_penalty[irq] +
846                                         PIRQ_PENALTY_ISA_USED;
847                 else
848                         new_penalty = 0;
849 
850                 acpi_isa_irq_penalty[irq] = new_penalty;
851                 if (retval != 2)        /* no next number */
852                         break;
853         }
854         return 1;
855 }
856 
857 /*
858  * We'd like PNP to call this routine for the
859  * single ISA_USED value for each legacy device.
860  * But instead it calls us with each POSSIBLE setting.
861  * There is no ISA_POSSIBLE weight, so we simply use
862  * the (small) PCI_USING penalty.
863  */
864 void acpi_penalize_isa_irq(int irq, int active)
865 {
866         if ((irq >= 0) && (irq < ARRAY_SIZE(acpi_isa_irq_penalty)))
867                 acpi_isa_irq_penalty[irq] +=
868                   (active ? PIRQ_PENALTY_ISA_USED : PIRQ_PENALTY_PCI_USING);
869 }
870 
871 bool acpi_isa_irq_available(int irq)
872 {
873         return irq >= 0 && (irq >= ARRAY_SIZE(acpi_isa_irq_penalty) ||
874                     acpi_irq_get_penalty(irq) < PIRQ_PENALTY_ISA_ALWAYS);
875 }
876 
877 void acpi_penalize_sci_irq(int irq, int trigger, int polarity)
878 {
879         sci_irq = irq;
880 
881         if (trigger == ACPI_MADT_TRIGGER_LEVEL &&
882             polarity == ACPI_MADT_POLARITY_ACTIVE_LOW)
883                 sci_penalty = PIRQ_PENALTY_PCI_USING;
884         else
885                 sci_penalty = PIRQ_PENALTY_ISA_ALWAYS;
886 }
887 
888 /*
889  * Over-ride default table to reserve additional IRQs for use by ISA
890  * e.g. acpi_irq_isa=5
891  * Useful for telling ACPI how not to interfere with your ISA sound card.
892  */
893 static int __init acpi_irq_isa(char *str)
894 {
895         return acpi_irq_penalty_update(str, 1);
896 }
897 
898 __setup("acpi_irq_isa=", acpi_irq_isa);
899 
900 /*
901  * Over-ride default table to free additional IRQs for use by PCI
902  * e.g. acpi_irq_pci=7,15
903  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
904  */
905 static int __init acpi_irq_pci(char *str)
906 {
907         return acpi_irq_penalty_update(str, 0);
908 }
909 
910 __setup("acpi_irq_pci=", acpi_irq_pci);
911 
912 static int __init acpi_irq_nobalance_set(char *str)
913 {
914         acpi_irq_balance = 0;
915         return 1;
916 }
917 
918 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
919 
920 static int __init acpi_irq_balance_set(char *str)
921 {
922         acpi_irq_balance = 1;
923         return 1;
924 }
925 
926 __setup("acpi_irq_balance", acpi_irq_balance_set);
927 
928 static struct syscore_ops irqrouter_syscore_ops = {
929         .resume = irqrouter_resume,
930 };
931 
932 void __init acpi_pci_link_init(void)
933 {
934         if (acpi_noirq)
935                 return;
936 
937         if (acpi_irq_balance == -1) {
938                 /* no command line switch: enable balancing in IOAPIC mode */
939                 if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
940                         acpi_irq_balance = 1;
941                 else
942                         acpi_irq_balance = 0;
943         }
944         register_syscore_ops(&irqrouter_syscore_ops);
945         acpi_scan_add_handler(&pci_link_handler);
946 }
947 

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