xref: /openbmc/linux/drivers/acpi/pci_link.c (revision fd589a8f)
1 /*
2  *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
7  *
8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or (at
13  *  your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful, but
16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  *  General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with this program; if not, write to the Free Software Foundation, Inc.,
22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23  *
24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25  *
26  * TBD:
27  *      1. Support more than one IRQ resource entry per link device (index).
28  *	2. Implement start/stop mechanism and use ACPI Bus Driver facilities
29  *	   for IRQ management (e.g. start()->_SRS).
30  */
31 
32 #include <linux/sysdev.h>
33 #include <linux/kernel.h>
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/proc_fs.h>
38 #include <linux/spinlock.h>
39 #include <linux/pm.h>
40 #include <linux/pci.h>
41 #include <linux/mutex.h>
42 
43 #include <acpi/acpi_bus.h>
44 #include <acpi/acpi_drivers.h>
45 
46 #define _COMPONENT			ACPI_PCI_COMPONENT
47 ACPI_MODULE_NAME("pci_link");
48 #define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
49 #define ACPI_PCI_LINK_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 static int acpi_pci_link_remove(struct acpi_device *device, int type);
56 
57 static struct acpi_device_id link_device_ids[] = {
58 	{"PNP0C0F", 0},
59 	{"", 0},
60 };
61 MODULE_DEVICE_TABLE(acpi, link_device_ids);
62 
63 static struct acpi_driver acpi_pci_link_driver = {
64 	.name = "pci_link",
65 	.class = ACPI_PCI_LINK_CLASS,
66 	.ids = link_device_ids,
67 	.ops = {
68 		.add = acpi_pci_link_add,
69 		.remove = acpi_pci_link_remove,
70 	},
71 };
72 
73 /*
74  * If a link is initialized, we never change its active and initialized
75  * later even the link is disable. Instead, we just repick the active irq
76  */
77 struct acpi_pci_link_irq {
78 	u8 active;		/* Current IRQ */
79 	u8 triggering;		/* All IRQs */
80 	u8 polarity;		/* All IRQs */
81 	u8 resource_type;
82 	u8 possible_count;
83 	u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
84 	u8 initialized:1;
85 	u8 reserved:7;
86 };
87 
88 struct acpi_pci_link {
89 	struct list_head		list;
90 	struct acpi_device		*device;
91 	struct acpi_pci_link_irq	irq;
92 	int				refcnt;
93 };
94 
95 static LIST_HEAD(acpi_link_list);
96 static DEFINE_MUTEX(acpi_link_lock);
97 
98 /* --------------------------------------------------------------------------
99                             PCI Link Device Management
100    -------------------------------------------------------------------------- */
101 
102 /*
103  * set context (link) possible list from resource list
104  */
105 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
106 						void *context)
107 {
108 	struct acpi_pci_link *link = context;
109 	u32 i;
110 
111 	switch (resource->type) {
112 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
113 	case ACPI_RESOURCE_TYPE_END_TAG:
114 		return AE_OK;
115 	case ACPI_RESOURCE_TYPE_IRQ:
116 		{
117 			struct acpi_resource_irq *p = &resource->data.irq;
118 			if (!p || !p->interrupt_count) {
119 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
120 						  "Blank _PRS IRQ resource\n"));
121 				return AE_OK;
122 			}
123 			for (i = 0;
124 			     (i < p->interrupt_count
125 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
126 				if (!p->interrupts[i]) {
127 					printk(KERN_WARNING PREFIX
128 					       "Invalid _PRS IRQ %d\n",
129 					       p->interrupts[i]);
130 					continue;
131 				}
132 				link->irq.possible[i] = p->interrupts[i];
133 				link->irq.possible_count++;
134 			}
135 			link->irq.triggering = p->triggering;
136 			link->irq.polarity = p->polarity;
137 			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
138 			break;
139 		}
140 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
141 		{
142 			struct acpi_resource_extended_irq *p =
143 			    &resource->data.extended_irq;
144 			if (!p || !p->interrupt_count) {
145 				printk(KERN_WARNING PREFIX
146 					      "Blank _PRS EXT IRQ resource\n");
147 				return AE_OK;
148 			}
149 			for (i = 0;
150 			     (i < p->interrupt_count
151 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
152 				if (!p->interrupts[i]) {
153 					printk(KERN_WARNING PREFIX
154 					       "Invalid _PRS IRQ %d\n",
155 					       p->interrupts[i]);
156 					continue;
157 				}
158 				link->irq.possible[i] = p->interrupts[i];
159 				link->irq.possible_count++;
160 			}
161 			link->irq.triggering = p->triggering;
162 			link->irq.polarity = p->polarity;
163 			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
164 			break;
165 		}
166 	default:
167 		printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
168 		       resource->type);
169 		return AE_OK;
170 	}
171 
172 	return AE_CTRL_TERMINATE;
173 }
174 
175 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
176 {
177 	acpi_status status;
178 
179 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
180 				     acpi_pci_link_check_possible, link);
181 	if (ACPI_FAILURE(status)) {
182 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
183 		return -ENODEV;
184 	}
185 
186 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
187 			  "Found %d possible IRQs\n",
188 			  link->irq.possible_count));
189 
190 	return 0;
191 }
192 
193 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
194 					       void *context)
195 {
196 	int *irq = context;
197 
198 	switch (resource->type) {
199 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
200 	case ACPI_RESOURCE_TYPE_END_TAG:
201 		return AE_OK;
202 	case ACPI_RESOURCE_TYPE_IRQ:
203 		{
204 			struct acpi_resource_irq *p = &resource->data.irq;
205 			if (!p || !p->interrupt_count) {
206 				/*
207 				 * IRQ descriptors may have no IRQ# bits set,
208 				 * particularly those those w/ _STA disabled
209 				 */
210 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
211 						  "Blank _CRS IRQ resource\n"));
212 				return AE_OK;
213 			}
214 			*irq = p->interrupts[0];
215 			break;
216 		}
217 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
218 		{
219 			struct acpi_resource_extended_irq *p =
220 			    &resource->data.extended_irq;
221 			if (!p || !p->interrupt_count) {
222 				/*
223 				 * extended IRQ descriptors must
224 				 * return at least 1 IRQ
225 				 */
226 				printk(KERN_WARNING PREFIX
227 					      "Blank _CRS EXT IRQ resource\n");
228 				return AE_OK;
229 			}
230 			*irq = p->interrupts[0];
231 			break;
232 		}
233 		break;
234 	default:
235 		printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
236 		       resource->type);
237 		return AE_OK;
238 	}
239 
240 	return AE_CTRL_TERMINATE;
241 }
242 
243 /*
244  * Run _CRS and set link->irq.active
245  *
246  * return value:
247  * 0 - success
248  * !0 - failure
249  */
250 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
251 {
252 	int result = 0;
253 	acpi_status status;
254 	int irq = 0;
255 
256 	link->irq.active = 0;
257 
258 	/* in practice, status disabled is meaningless, ignore it */
259 	if (acpi_strict) {
260 		/* Query _STA, set link->device->status */
261 		result = acpi_bus_get_status(link->device);
262 		if (result) {
263 			printk(KERN_ERR PREFIX "Unable to read status\n");
264 			goto end;
265 		}
266 
267 		if (!link->device->status.enabled) {
268 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
269 			return 0;
270 		}
271 	}
272 
273 	/*
274 	 * Query and parse _CRS to get the current IRQ assignment.
275 	 */
276 
277 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
278 				     acpi_pci_link_check_current, &irq);
279 	if (ACPI_FAILURE(status)) {
280 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
281 		result = -ENODEV;
282 		goto end;
283 	}
284 
285 	if (acpi_strict && !irq) {
286 		printk(KERN_ERR PREFIX "_CRS returned 0\n");
287 		result = -ENODEV;
288 	}
289 
290 	link->irq.active = irq;
291 
292 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
293 
294       end:
295 	return result;
296 }
297 
298 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
299 {
300 	int result;
301 	acpi_status status;
302 	struct {
303 		struct acpi_resource res;
304 		struct acpi_resource end;
305 	} *resource;
306 	struct acpi_buffer buffer = { 0, NULL };
307 
308 	if (!irq)
309 		return -EINVAL;
310 
311 	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
312 	if (!resource)
313 		return -ENOMEM;
314 
315 	buffer.length = sizeof(*resource) + 1;
316 	buffer.pointer = resource;
317 
318 	switch (link->irq.resource_type) {
319 	case ACPI_RESOURCE_TYPE_IRQ:
320 		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
321 		resource->res.length = sizeof(struct acpi_resource);
322 		resource->res.data.irq.triggering = link->irq.triggering;
323 		resource->res.data.irq.polarity =
324 		    link->irq.polarity;
325 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
326 			resource->res.data.irq.sharable =
327 			    ACPI_EXCLUSIVE;
328 		else
329 			resource->res.data.irq.sharable = ACPI_SHARED;
330 		resource->res.data.irq.interrupt_count = 1;
331 		resource->res.data.irq.interrupts[0] = irq;
332 		break;
333 
334 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
335 		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
336 		resource->res.length = sizeof(struct acpi_resource);
337 		resource->res.data.extended_irq.producer_consumer =
338 		    ACPI_CONSUMER;
339 		resource->res.data.extended_irq.triggering =
340 		    link->irq.triggering;
341 		resource->res.data.extended_irq.polarity =
342 		    link->irq.polarity;
343 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
344 			resource->res.data.irq.sharable =
345 			    ACPI_EXCLUSIVE;
346 		else
347 			resource->res.data.irq.sharable = ACPI_SHARED;
348 		resource->res.data.extended_irq.interrupt_count = 1;
349 		resource->res.data.extended_irq.interrupts[0] = irq;
350 		/* ignore resource_source, it's optional */
351 		break;
352 	default:
353 		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
354 		result = -EINVAL;
355 		goto end;
356 
357 	}
358 	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
359 
360 	/* Attempt to set the resource */
361 	status = acpi_set_current_resources(link->device->handle, &buffer);
362 
363 	/* check for total failure */
364 	if (ACPI_FAILURE(status)) {
365 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
366 		result = -ENODEV;
367 		goto end;
368 	}
369 
370 	/* Query _STA, set device->status */
371 	result = acpi_bus_get_status(link->device);
372 	if (result) {
373 		printk(KERN_ERR PREFIX "Unable to read status\n");
374 		goto end;
375 	}
376 	if (!link->device->status.enabled) {
377 		printk(KERN_WARNING PREFIX
378 			      "%s [%s] disabled and referenced, BIOS bug\n",
379 			      acpi_device_name(link->device),
380 			      acpi_device_bid(link->device));
381 	}
382 
383 	/* Query _CRS, set link->irq.active */
384 	result = acpi_pci_link_get_current(link);
385 	if (result) {
386 		goto end;
387 	}
388 
389 	/*
390 	 * Is current setting not what we set?
391 	 * set link->irq.active
392 	 */
393 	if (link->irq.active != irq) {
394 		/*
395 		 * policy: when _CRS doesn't return what we just _SRS
396 		 * assume _SRS worked and override _CRS value.
397 		 */
398 		printk(KERN_WARNING PREFIX
399 			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
400 			      acpi_device_name(link->device),
401 			      acpi_device_bid(link->device), link->irq.active, irq);
402 		link->irq.active = irq;
403 	}
404 
405 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
406 
407       end:
408 	kfree(resource);
409 	return result;
410 }
411 
412 /* --------------------------------------------------------------------------
413                             PCI Link IRQ Management
414    -------------------------------------------------------------------------- */
415 
416 /*
417  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
418  * Link Devices to move the PIRQs around to minimize sharing.
419  *
420  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
421  * that the BIOS has already set to active.  This is necessary because
422  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
423  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
424  * even if acpi_irq_nobalance is set.
425  *
426  * A tables of penalties avoids directing PCI interrupts to well known
427  * ISA IRQs. Boot params are available to over-ride the default table:
428  *
429  * List interrupts that are free for PCI use.
430  * acpi_irq_pci=n[,m]
431  *
432  * List interrupts that should not be used for PCI:
433  * acpi_irq_isa=n[,m]
434  *
435  * Note that PCI IRQ routers have a list of possible IRQs,
436  * which may not include the IRQs this table says are available.
437  *
438  * Since this heuristic can't tell the difference between a link
439  * that no device will attach to, vs. a link which may be shared
440  * by multiple active devices -- it is not optimal.
441  *
442  * If interrupt performance is that important, get an IO-APIC system
443  * with a pin dedicated to each device.  Or for that matter, an MSI
444  * enabled system.
445  */
446 
447 #define ACPI_MAX_IRQS		256
448 #define ACPI_MAX_ISA_IRQ	16
449 
450 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
451 #define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
452 #define PIRQ_PENALTY_PCI_USING		(16*16*16)
453 #define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
454 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
455 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
456 
457 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
458 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
459 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
460 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
461 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
462 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
463 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
464 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
465 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
466 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
467 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
468 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
469 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
470 	PIRQ_PENALTY_ISA_USED,		/* IRQ12 mouse */
471 	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
472 	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
473 	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
474 	/* >IRQ15 */
475 };
476 
477 int __init acpi_irq_penalty_init(void)
478 {
479 	struct acpi_pci_link *link;
480 	int i;
481 
482 	/*
483 	 * Update penalties to facilitate IRQ balancing.
484 	 */
485 	list_for_each_entry(link, &acpi_link_list, list) {
486 
487 		/*
488 		 * reflect the possible and active irqs in the penalty table --
489 		 * useful for breaking ties.
490 		 */
491 		if (link->irq.possible_count) {
492 			int penalty =
493 			    PIRQ_PENALTY_PCI_POSSIBLE /
494 			    link->irq.possible_count;
495 
496 			for (i = 0; i < link->irq.possible_count; i++) {
497 				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
498 					acpi_irq_penalty[link->irq.
499 							 possible[i]] +=
500 					    penalty;
501 			}
502 
503 		} else if (link->irq.active) {
504 			acpi_irq_penalty[link->irq.active] +=
505 			    PIRQ_PENALTY_PCI_POSSIBLE;
506 		}
507 	}
508 	/* Add a penalty for the SCI */
509 	acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
510 	return 0;
511 }
512 
513 static int acpi_irq_balance = -1;	/* 0: static, 1: balance */
514 
515 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
516 {
517 	int irq;
518 	int i;
519 
520 	if (link->irq.initialized) {
521 		if (link->refcnt == 0)
522 			/* This means the link is disabled but initialized */
523 			acpi_pci_link_set(link, link->irq.active);
524 		return 0;
525 	}
526 
527 	/*
528 	 * search for active IRQ in list of possible IRQs.
529 	 */
530 	for (i = 0; i < link->irq.possible_count; ++i) {
531 		if (link->irq.active == link->irq.possible[i])
532 			break;
533 	}
534 	/*
535 	 * forget active IRQ that is not in possible list
536 	 */
537 	if (i == link->irq.possible_count) {
538 		if (acpi_strict)
539 			printk(KERN_WARNING PREFIX "_CRS %d not found"
540 				      " in _PRS\n", link->irq.active);
541 		link->irq.active = 0;
542 	}
543 
544 	/*
545 	 * if active found, use it; else pick entry from end of possible list.
546 	 */
547 	if (link->irq.active)
548 		irq = link->irq.active;
549 	else
550 		irq = link->irq.possible[link->irq.possible_count - 1];
551 
552 	if (acpi_irq_balance || !link->irq.active) {
553 		/*
554 		 * Select the best IRQ.  This is done in reverse to promote
555 		 * the use of IRQs 9, 10, 11, and >15.
556 		 */
557 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
558 			if (acpi_irq_penalty[irq] >
559 			    acpi_irq_penalty[link->irq.possible[i]])
560 				irq = link->irq.possible[i];
561 		}
562 	}
563 
564 	/* Attempt to enable the link device at this IRQ. */
565 	if (acpi_pci_link_set(link, irq)) {
566 		printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
567 			    "Try pci=noacpi or acpi=off\n",
568 			    acpi_device_name(link->device),
569 			    acpi_device_bid(link->device));
570 		return -ENODEV;
571 	} else {
572 		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
573 		printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
574 		       acpi_device_name(link->device),
575 		       acpi_device_bid(link->device), link->irq.active);
576 	}
577 
578 	link->irq.initialized = 1;
579 	return 0;
580 }
581 
582 /*
583  * acpi_pci_link_allocate_irq
584  * success: return IRQ >= 0
585  * failure: return -1
586  */
587 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
588 			       int *polarity, char **name)
589 {
590 	int result;
591 	struct acpi_device *device;
592 	struct acpi_pci_link *link;
593 
594 	result = acpi_bus_get_device(handle, &device);
595 	if (result) {
596 		printk(KERN_ERR PREFIX "Invalid link device\n");
597 		return -1;
598 	}
599 
600 	link = acpi_driver_data(device);
601 	if (!link) {
602 		printk(KERN_ERR PREFIX "Invalid link context\n");
603 		return -1;
604 	}
605 
606 	/* TBD: Support multiple index (IRQ) entries per Link Device */
607 	if (index) {
608 		printk(KERN_ERR PREFIX "Invalid index %d\n", index);
609 		return -1;
610 	}
611 
612 	mutex_lock(&acpi_link_lock);
613 	if (acpi_pci_link_allocate(link)) {
614 		mutex_unlock(&acpi_link_lock);
615 		return -1;
616 	}
617 
618 	if (!link->irq.active) {
619 		mutex_unlock(&acpi_link_lock);
620 		printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
621 		return -1;
622 	}
623 	link->refcnt++;
624 	mutex_unlock(&acpi_link_lock);
625 
626 	if (triggering)
627 		*triggering = link->irq.triggering;
628 	if (polarity)
629 		*polarity = link->irq.polarity;
630 	if (name)
631 		*name = acpi_device_bid(link->device);
632 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
633 			  "Link %s is referenced\n",
634 			  acpi_device_bid(link->device)));
635 	return (link->irq.active);
636 }
637 
638 /*
639  * We don't change link's irq information here.  After it is reenabled, we
640  * continue use the info
641  */
642 int acpi_pci_link_free_irq(acpi_handle handle)
643 {
644 	struct acpi_device *device;
645 	struct acpi_pci_link *link;
646 	acpi_status result;
647 
648 	result = acpi_bus_get_device(handle, &device);
649 	if (result) {
650 		printk(KERN_ERR PREFIX "Invalid link device\n");
651 		return -1;
652 	}
653 
654 	link = acpi_driver_data(device);
655 	if (!link) {
656 		printk(KERN_ERR PREFIX "Invalid link context\n");
657 		return -1;
658 	}
659 
660 	mutex_lock(&acpi_link_lock);
661 	if (!link->irq.initialized) {
662 		mutex_unlock(&acpi_link_lock);
663 		printk(KERN_ERR PREFIX "Link isn't initialized\n");
664 		return -1;
665 	}
666 #ifdef	FUTURE_USE
667 	/*
668 	 * The Link reference count allows us to _DISable an unused link
669 	 * and suspend time, and set it again  on resume.
670 	 * However, 2.6.12 still has irq_router.resume
671 	 * which blindly restores the link state.
672 	 * So we disable the reference count method
673 	 * to prevent duplicate acpi_pci_link_set()
674 	 * which would harm some systems
675 	 */
676 	link->refcnt--;
677 #endif
678 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
679 			  "Link %s is dereferenced\n",
680 			  acpi_device_bid(link->device)));
681 
682 	if (link->refcnt == 0)
683 		acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
684 
685 	mutex_unlock(&acpi_link_lock);
686 	return (link->irq.active);
687 }
688 
689 /* --------------------------------------------------------------------------
690                                  Driver Interface
691    -------------------------------------------------------------------------- */
692 
693 static int acpi_pci_link_add(struct acpi_device *device)
694 {
695 	int result;
696 	struct acpi_pci_link *link;
697 	int i;
698 	int found = 0;
699 
700 	link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
701 	if (!link)
702 		return -ENOMEM;
703 
704 	link->device = device;
705 	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
706 	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
707 	device->driver_data = link;
708 
709 	mutex_lock(&acpi_link_lock);
710 	result = acpi_pci_link_get_possible(link);
711 	if (result)
712 		goto end;
713 
714 	/* query and set link->irq.active */
715 	acpi_pci_link_get_current(link);
716 
717 	printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
718 	       acpi_device_bid(device));
719 	for (i = 0; i < link->irq.possible_count; i++) {
720 		if (link->irq.active == link->irq.possible[i]) {
721 			printk(" *%d", link->irq.possible[i]);
722 			found = 1;
723 		} else
724 			printk(" %d", link->irq.possible[i]);
725 	}
726 
727 	printk(")");
728 
729 	if (!found)
730 		printk(" *%d", link->irq.active);
731 
732 	if (!link->device->status.enabled)
733 		printk(", disabled.");
734 
735 	printk("\n");
736 
737 	list_add_tail(&link->list, &acpi_link_list);
738 
739       end:
740 	/* disable all links -- to be activated on use */
741 	acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
742 	mutex_unlock(&acpi_link_lock);
743 
744 	if (result)
745 		kfree(link);
746 
747 	return result;
748 }
749 
750 static int acpi_pci_link_resume(struct acpi_pci_link *link)
751 {
752 	if (link->refcnt && link->irq.active && link->irq.initialized)
753 		return (acpi_pci_link_set(link, link->irq.active));
754 
755 	return 0;
756 }
757 
758 static int irqrouter_resume(struct sys_device *dev)
759 {
760 	struct acpi_pci_link *link;
761 
762 	list_for_each_entry(link, &acpi_link_list, list) {
763 		acpi_pci_link_resume(link);
764 	}
765 	return 0;
766 }
767 
768 static int acpi_pci_link_remove(struct acpi_device *device, int type)
769 {
770 	struct acpi_pci_link *link;
771 
772 	link = acpi_driver_data(device);
773 
774 	mutex_lock(&acpi_link_lock);
775 	list_del(&link->list);
776 	mutex_unlock(&acpi_link_lock);
777 
778 	kfree(link);
779 	return 0;
780 }
781 
782 /*
783  * modify acpi_irq_penalty[] from cmdline
784  */
785 static int __init acpi_irq_penalty_update(char *str, int used)
786 {
787 	int i;
788 
789 	for (i = 0; i < 16; i++) {
790 		int retval;
791 		int irq;
792 
793 		retval = get_option(&str, &irq);
794 
795 		if (!retval)
796 			break;	/* no number found */
797 
798 		if (irq < 0)
799 			continue;
800 
801 		if (irq >= ARRAY_SIZE(acpi_irq_penalty))
802 			continue;
803 
804 		if (used)
805 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
806 		else
807 			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
808 
809 		if (retval != 2)	/* no next number */
810 			break;
811 	}
812 	return 1;
813 }
814 
815 /*
816  * We'd like PNP to call this routine for the
817  * single ISA_USED value for each legacy device.
818  * But instead it calls us with each POSSIBLE setting.
819  * There is no ISA_POSSIBLE weight, so we simply use
820  * the (small) PCI_USING penalty.
821  */
822 void acpi_penalize_isa_irq(int irq, int active)
823 {
824 	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
825 		if (active)
826 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
827 		else
828 			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
829 	}
830 }
831 
832 /*
833  * Over-ride default table to reserve additional IRQs for use by ISA
834  * e.g. acpi_irq_isa=5
835  * Useful for telling ACPI how not to interfere with your ISA sound card.
836  */
837 static int __init acpi_irq_isa(char *str)
838 {
839 	return acpi_irq_penalty_update(str, 1);
840 }
841 
842 __setup("acpi_irq_isa=", acpi_irq_isa);
843 
844 /*
845  * Over-ride default table to free additional IRQs for use by PCI
846  * e.g. acpi_irq_pci=7,15
847  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
848  */
849 static int __init acpi_irq_pci(char *str)
850 {
851 	return acpi_irq_penalty_update(str, 0);
852 }
853 
854 __setup("acpi_irq_pci=", acpi_irq_pci);
855 
856 static int __init acpi_irq_nobalance_set(char *str)
857 {
858 	acpi_irq_balance = 0;
859 	return 1;
860 }
861 
862 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
863 
864 static int __init acpi_irq_balance_set(char *str)
865 {
866 	acpi_irq_balance = 1;
867 	return 1;
868 }
869 
870 __setup("acpi_irq_balance", acpi_irq_balance_set);
871 
872 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
873 static struct sysdev_class irqrouter_sysdev_class = {
874 	.name = "irqrouter",
875 	.resume = irqrouter_resume,
876 };
877 
878 static struct sys_device device_irqrouter = {
879 	.id = 0,
880 	.cls = &irqrouter_sysdev_class,
881 };
882 
883 static int __init irqrouter_init_sysfs(void)
884 {
885 	int error;
886 
887 	if (acpi_disabled || acpi_noirq)
888 		return 0;
889 
890 	error = sysdev_class_register(&irqrouter_sysdev_class);
891 	if (!error)
892 		error = sysdev_register(&device_irqrouter);
893 
894 	return error;
895 }
896 
897 device_initcall(irqrouter_init_sysfs);
898 
899 static int __init acpi_pci_link_init(void)
900 {
901 	if (acpi_noirq)
902 		return 0;
903 
904 	if (acpi_irq_balance == -1) {
905 		/* no command line switch: enable balancing in IOAPIC mode */
906 		if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
907 			acpi_irq_balance = 1;
908 		else
909 			acpi_irq_balance = 0;
910 	}
911 
912 	if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
913 		return -ENODEV;
914 
915 	return 0;
916 }
917 
918 subsys_initcall(acpi_pci_link_init);
919