Pull trivial2 into release branch
[linux-2.6.git] / 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/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         acpi_in_resume = 1;
816         list_for_each(node, &acpi_link.entries) {
817                 link = list_entry(node, struct acpi_pci_link, node);
818                 if (!link) {
819                         ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
820                                           "Invalid link context\n"));
821                         continue;
822                 }
823                 acpi_pci_link_resume(link);
824         }
825         acpi_in_resume = 0;
826         return_VALUE(0);
827 }
828
829 static int acpi_pci_link_remove(struct acpi_device *device, int type)
830 {
831         struct acpi_pci_link *link = NULL;
832
833         ACPI_FUNCTION_TRACE("acpi_pci_link_remove");
834
835         if (!device || !acpi_driver_data(device))
836                 return_VALUE(-EINVAL);
837
838         link = (struct acpi_pci_link *)acpi_driver_data(device);
839
840         down(&acpi_link_lock);
841         list_del(&link->node);
842         up(&acpi_link_lock);
843
844         kfree(link);
845
846         return_VALUE(0);
847 }
848
849 /*
850  * modify acpi_irq_penalty[] from cmdline
851  */
852 static int __init acpi_irq_penalty_update(char *str, int used)
853 {
854         int i;
855
856         for (i = 0; i < 16; i++) {
857                 int retval;
858                 int irq;
859
860                 retval = get_option(&str, &irq);
861
862                 if (!retval)
863                         break;  /* no number found */
864
865                 if (irq < 0)
866                         continue;
867
868                 if (irq >= ACPI_MAX_IRQS)
869                         continue;
870
871                 if (used)
872                         acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
873                 else
874                         acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
875
876                 if (retval != 2)        /* no next number */
877                         break;
878         }
879         return 1;
880 }
881
882 /*
883  * We'd like PNP to call this routine for the
884  * single ISA_USED value for each legacy device.
885  * But instead it calls us with each POSSIBLE setting.
886  * There is no ISA_POSSIBLE weight, so we simply use
887  * the (small) PCI_USING penalty.
888  */
889 void acpi_penalize_isa_irq(int irq, int active)
890 {
891         if (active)
892                 acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
893         else
894                 acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
895 }
896
897 /*
898  * Over-ride default table to reserve additional IRQs for use by ISA
899  * e.g. acpi_irq_isa=5
900  * Useful for telling ACPI how not to interfere with your ISA sound card.
901  */
902 static int __init acpi_irq_isa(char *str)
903 {
904         return acpi_irq_penalty_update(str, 1);
905 }
906
907 __setup("acpi_irq_isa=", acpi_irq_isa);
908
909 /*
910  * Over-ride default table to free additional IRQs for use by PCI
911  * e.g. acpi_irq_pci=7,15
912  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
913  */
914 static int __init acpi_irq_pci(char *str)
915 {
916         return acpi_irq_penalty_update(str, 0);
917 }
918
919 __setup("acpi_irq_pci=", acpi_irq_pci);
920
921 static int __init acpi_irq_nobalance_set(char *str)
922 {
923         acpi_irq_balance = 0;
924         return 1;
925 }
926
927 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
928
929 int __init acpi_irq_balance_set(char *str)
930 {
931         acpi_irq_balance = 1;
932         return 1;
933 }
934
935 __setup("acpi_irq_balance", acpi_irq_balance_set);
936
937 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
938 static struct sysdev_class irqrouter_sysdev_class = {
939         set_kset_name("irqrouter"),
940         .resume = irqrouter_resume,
941 };
942
943 static struct sys_device device_irqrouter = {
944         .id = 0,
945         .cls = &irqrouter_sysdev_class,
946 };
947
948 static int __init irqrouter_init_sysfs(void)
949 {
950         int error;
951
952         ACPI_FUNCTION_TRACE("irqrouter_init_sysfs");
953
954         if (acpi_disabled || acpi_noirq)
955                 return_VALUE(0);
956
957         error = sysdev_class_register(&irqrouter_sysdev_class);
958         if (!error)
959                 error = sysdev_register(&device_irqrouter);
960
961         return_VALUE(error);
962 }
963
964 device_initcall(irqrouter_init_sysfs);
965
966 static int __init acpi_pci_link_init(void)
967 {
968         ACPI_FUNCTION_TRACE("acpi_pci_link_init");
969
970         if (acpi_noirq)
971                 return_VALUE(0);
972
973         acpi_link.count = 0;
974         INIT_LIST_HEAD(&acpi_link.entries);
975
976         if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
977                 return_VALUE(-ENODEV);
978
979         return_VALUE(0);
980 }
981
982 subsys_initcall(acpi_pci_link_init);