xref: /linux/drivers/acpi/pci_link.c (revision 47902f3611b392209e2a412bf7ec02dca95e666d)
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 #include <linux/slab.h>
43 
44 #include <acpi/acpi_bus.h>
45 #include <acpi/acpi_drivers.h>
46 
47 #define PREFIX "ACPI: "
48 
49 #define _COMPONENT			ACPI_PCI_COMPONENT
50 ACPI_MODULE_NAME("pci_link");
51 #define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
52 #define ACPI_PCI_LINK_DEVICE_NAME	"PCI Interrupt Link"
53 #define ACPI_PCI_LINK_FILE_INFO		"info"
54 #define ACPI_PCI_LINK_FILE_STATUS	"state"
55 #define ACPI_PCI_LINK_MAX_POSSIBLE	16
56 
57 static int acpi_pci_link_add(struct acpi_device *device);
58 static int acpi_pci_link_remove(struct acpi_device *device, int type);
59 
60 static const struct acpi_device_id link_device_ids[] = {
61 	{"PNP0C0F", 0},
62 	{"", 0},
63 };
64 MODULE_DEVICE_TABLE(acpi, link_device_ids);
65 
66 static struct acpi_driver acpi_pci_link_driver = {
67 	.name = "pci_link",
68 	.class = ACPI_PCI_LINK_CLASS,
69 	.ids = link_device_ids,
70 	.ops = {
71 		.add = acpi_pci_link_add,
72 		.remove = acpi_pci_link_remove,
73 	},
74 };
75 
76 /*
77  * If a link is initialized, we never change its active and initialized
78  * later even the link is disable. Instead, we just repick the active irq
79  */
80 struct acpi_pci_link_irq {
81 	u8 active;		/* Current IRQ */
82 	u8 triggering;		/* All IRQs */
83 	u8 polarity;		/* All IRQs */
84 	u8 resource_type;
85 	u8 possible_count;
86 	u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
87 	u8 initialized:1;
88 	u8 reserved:7;
89 };
90 
91 struct acpi_pci_link {
92 	struct list_head		list;
93 	struct acpi_device		*device;
94 	struct acpi_pci_link_irq	irq;
95 	int				refcnt;
96 };
97 
98 static LIST_HEAD(acpi_link_list);
99 static DEFINE_MUTEX(acpi_link_lock);
100 
101 /* --------------------------------------------------------------------------
102                             PCI Link Device Management
103    -------------------------------------------------------------------------- */
104 
105 /*
106  * set context (link) possible list from resource list
107  */
108 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
109 						void *context)
110 {
111 	struct acpi_pci_link *link = context;
112 	u32 i;
113 
114 	switch (resource->type) {
115 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
116 	case ACPI_RESOURCE_TYPE_END_TAG:
117 		return AE_OK;
118 	case ACPI_RESOURCE_TYPE_IRQ:
119 		{
120 			struct acpi_resource_irq *p = &resource->data.irq;
121 			if (!p || !p->interrupt_count) {
122 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
123 						  "Blank _PRS IRQ resource\n"));
124 				return AE_OK;
125 			}
126 			for (i = 0;
127 			     (i < p->interrupt_count
128 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
129 				if (!p->interrupts[i]) {
130 					printk(KERN_WARNING PREFIX
131 					       "Invalid _PRS IRQ %d\n",
132 					       p->interrupts[i]);
133 					continue;
134 				}
135 				link->irq.possible[i] = p->interrupts[i];
136 				link->irq.possible_count++;
137 			}
138 			link->irq.triggering = p->triggering;
139 			link->irq.polarity = p->polarity;
140 			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
141 			break;
142 		}
143 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
144 		{
145 			struct acpi_resource_extended_irq *p =
146 			    &resource->data.extended_irq;
147 			if (!p || !p->interrupt_count) {
148 				printk(KERN_WARNING PREFIX
149 					      "Blank _PRS EXT IRQ resource\n");
150 				return AE_OK;
151 			}
152 			for (i = 0;
153 			     (i < p->interrupt_count
154 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
155 				if (!p->interrupts[i]) {
156 					printk(KERN_WARNING PREFIX
157 					       "Invalid _PRS IRQ %d\n",
158 					       p->interrupts[i]);
159 					continue;
160 				}
161 				link->irq.possible[i] = p->interrupts[i];
162 				link->irq.possible_count++;
163 			}
164 			link->irq.triggering = p->triggering;
165 			link->irq.polarity = p->polarity;
166 			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
167 			break;
168 		}
169 	default:
170 		printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
171 		       resource->type);
172 		return AE_OK;
173 	}
174 
175 	return AE_CTRL_TERMINATE;
176 }
177 
178 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
179 {
180 	acpi_status status;
181 
182 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
183 				     acpi_pci_link_check_possible, link);
184 	if (ACPI_FAILURE(status)) {
185 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
186 		return -ENODEV;
187 	}
188 
189 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
190 			  "Found %d possible IRQs\n",
191 			  link->irq.possible_count));
192 
193 	return 0;
194 }
195 
196 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
197 					       void *context)
198 {
199 	int *irq = context;
200 
201 	switch (resource->type) {
202 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
203 	case ACPI_RESOURCE_TYPE_END_TAG:
204 		return AE_OK;
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 _CRS IRQ resource\n"));
215 				return 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 				printk(KERN_WARNING PREFIX
230 					      "Blank _CRS EXT IRQ resource\n");
231 				return AE_OK;
232 			}
233 			*irq = p->interrupts[0];
234 			break;
235 		}
236 		break;
237 	default:
238 		printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
239 		       resource->type);
240 		return AE_OK;
241 	}
242 
243 	return AE_CTRL_TERMINATE;
244 }
245 
246 /*
247  * Run _CRS and set link->irq.active
248  *
249  * return value:
250  * 0 - success
251  * !0 - failure
252  */
253 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
254 {
255 	int result = 0;
256 	acpi_status status;
257 	int irq = 0;
258 
259 	link->irq.active = 0;
260 
261 	/* in practice, status disabled is meaningless, ignore it */
262 	if (acpi_strict) {
263 		/* Query _STA, set link->device->status */
264 		result = acpi_bus_get_status(link->device);
265 		if (result) {
266 			printk(KERN_ERR PREFIX "Unable to read status\n");
267 			goto end;
268 		}
269 
270 		if (!link->device->status.enabled) {
271 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
272 			return 0;
273 		}
274 	}
275 
276 	/*
277 	 * Query and parse _CRS to get the current IRQ assignment.
278 	 */
279 
280 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
281 				     acpi_pci_link_check_current, &irq);
282 	if (ACPI_FAILURE(status)) {
283 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
284 		result = -ENODEV;
285 		goto end;
286 	}
287 
288 	if (acpi_strict && !irq) {
289 		printk(KERN_ERR PREFIX "_CRS returned 0\n");
290 		result = -ENODEV;
291 	}
292 
293 	link->irq.active = irq;
294 
295 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
296 
297       end:
298 	return result;
299 }
300 
301 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
302 {
303 	int result;
304 	acpi_status status;
305 	struct {
306 		struct acpi_resource res;
307 		struct acpi_resource end;
308 	} *resource;
309 	struct acpi_buffer buffer = { 0, NULL };
310 
311 	if (!irq)
312 		return -EINVAL;
313 
314 	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
315 	if (!resource)
316 		return -ENOMEM;
317 
318 	buffer.length = sizeof(*resource) + 1;
319 	buffer.pointer = resource;
320 
321 	switch (link->irq.resource_type) {
322 	case ACPI_RESOURCE_TYPE_IRQ:
323 		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
324 		resource->res.length = sizeof(struct acpi_resource);
325 		resource->res.data.irq.triggering = link->irq.triggering;
326 		resource->res.data.irq.polarity =
327 		    link->irq.polarity;
328 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
329 			resource->res.data.irq.sharable =
330 			    ACPI_EXCLUSIVE;
331 		else
332 			resource->res.data.irq.sharable = ACPI_SHARED;
333 		resource->res.data.irq.interrupt_count = 1;
334 		resource->res.data.irq.interrupts[0] = irq;
335 		break;
336 
337 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
338 		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
339 		resource->res.length = sizeof(struct acpi_resource);
340 		resource->res.data.extended_irq.producer_consumer =
341 		    ACPI_CONSUMER;
342 		resource->res.data.extended_irq.triggering =
343 		    link->irq.triggering;
344 		resource->res.data.extended_irq.polarity =
345 		    link->irq.polarity;
346 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
347 			resource->res.data.irq.sharable =
348 			    ACPI_EXCLUSIVE;
349 		else
350 			resource->res.data.irq.sharable = ACPI_SHARED;
351 		resource->res.data.extended_irq.interrupt_count = 1;
352 		resource->res.data.extended_irq.interrupts[0] = irq;
353 		/* ignore resource_source, it's optional */
354 		break;
355 	default:
356 		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
357 		result = -EINVAL;
358 		goto end;
359 
360 	}
361 	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
362 
363 	/* Attempt to set the resource */
364 	status = acpi_set_current_resources(link->device->handle, &buffer);
365 
366 	/* check for total failure */
367 	if (ACPI_FAILURE(status)) {
368 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
369 		result = -ENODEV;
370 		goto end;
371 	}
372 
373 	/* Query _STA, set device->status */
374 	result = acpi_bus_get_status(link->device);
375 	if (result) {
376 		printk(KERN_ERR PREFIX "Unable to read status\n");
377 		goto end;
378 	}
379 	if (!link->device->status.enabled) {
380 		printk(KERN_WARNING PREFIX
381 			      "%s [%s] disabled and referenced, BIOS bug\n",
382 			      acpi_device_name(link->device),
383 			      acpi_device_bid(link->device));
384 	}
385 
386 	/* Query _CRS, set link->irq.active */
387 	result = acpi_pci_link_get_current(link);
388 	if (result) {
389 		goto end;
390 	}
391 
392 	/*
393 	 * Is current setting not what we set?
394 	 * set link->irq.active
395 	 */
396 	if (link->irq.active != irq) {
397 		/*
398 		 * policy: when _CRS doesn't return what we just _SRS
399 		 * assume _SRS worked and override _CRS value.
400 		 */
401 		printk(KERN_WARNING PREFIX
402 			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
403 			      acpi_device_name(link->device),
404 			      acpi_device_bid(link->device), link->irq.active, irq);
405 		link->irq.active = irq;
406 	}
407 
408 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
409 
410       end:
411 	kfree(resource);
412 	return result;
413 }
414 
415 /* --------------------------------------------------------------------------
416                             PCI Link IRQ Management
417    -------------------------------------------------------------------------- */
418 
419 /*
420  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
421  * Link Devices to move the PIRQs around to minimize sharing.
422  *
423  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
424  * that the BIOS has already set to active.  This is necessary because
425  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
426  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
427  * even if acpi_irq_nobalance is set.
428  *
429  * A tables of penalties avoids directing PCI interrupts to well known
430  * ISA IRQs. Boot params are available to over-ride the default table:
431  *
432  * List interrupts that are free for PCI use.
433  * acpi_irq_pci=n[,m]
434  *
435  * List interrupts that should not be used for PCI:
436  * acpi_irq_isa=n[,m]
437  *
438  * Note that PCI IRQ routers have a list of possible IRQs,
439  * which may not include the IRQs this table says are available.
440  *
441  * Since this heuristic can't tell the difference between a link
442  * that no device will attach to, vs. a link which may be shared
443  * by multiple active devices -- it is not optimal.
444  *
445  * If interrupt performance is that important, get an IO-APIC system
446  * with a pin dedicated to each device.  Or for that matter, an MSI
447  * enabled system.
448  */
449 
450 #define ACPI_MAX_IRQS		256
451 #define ACPI_MAX_ISA_IRQ	16
452 
453 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
454 #define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
455 #define PIRQ_PENALTY_PCI_USING		(16*16*16)
456 #define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
457 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
458 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
459 
460 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
461 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
462 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
463 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
464 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
465 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
466 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
467 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
468 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
469 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
470 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
471 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
472 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
473 	PIRQ_PENALTY_ISA_USED,		/* IRQ12 mouse */
474 	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
475 	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
476 	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
477 	/* >IRQ15 */
478 };
479 
480 int __init acpi_irq_penalty_init(void)
481 {
482 	struct acpi_pci_link *link;
483 	int i;
484 
485 	/*
486 	 * Update penalties to facilitate IRQ balancing.
487 	 */
488 	list_for_each_entry(link, &acpi_link_list, list) {
489 
490 		/*
491 		 * reflect the possible and active irqs in the penalty table --
492 		 * useful for breaking ties.
493 		 */
494 		if (link->irq.possible_count) {
495 			int penalty =
496 			    PIRQ_PENALTY_PCI_POSSIBLE /
497 			    link->irq.possible_count;
498 
499 			for (i = 0; i < link->irq.possible_count; i++) {
500 				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
501 					acpi_irq_penalty[link->irq.
502 							 possible[i]] +=
503 					    penalty;
504 			}
505 
506 		} else if (link->irq.active) {
507 			acpi_irq_penalty[link->irq.active] +=
508 			    PIRQ_PENALTY_PCI_POSSIBLE;
509 		}
510 	}
511 	/* Add a penalty for the SCI */
512 	acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
513 	return 0;
514 }
515 
516 static int acpi_irq_balance = -1;	/* 0: static, 1: balance */
517 
518 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
519 {
520 	int irq;
521 	int i;
522 
523 	if (link->irq.initialized) {
524 		if (link->refcnt == 0)
525 			/* This means the link is disabled but initialized */
526 			acpi_pci_link_set(link, link->irq.active);
527 		return 0;
528 	}
529 
530 	/*
531 	 * search for active IRQ in list of possible IRQs.
532 	 */
533 	for (i = 0; i < link->irq.possible_count; ++i) {
534 		if (link->irq.active == link->irq.possible[i])
535 			break;
536 	}
537 	/*
538 	 * forget active IRQ that is not in possible list
539 	 */
540 	if (i == link->irq.possible_count) {
541 		if (acpi_strict)
542 			printk(KERN_WARNING PREFIX "_CRS %d not found"
543 				      " in _PRS\n", link->irq.active);
544 		link->irq.active = 0;
545 	}
546 
547 	/*
548 	 * if active found, use it; else pick entry from end of possible list.
549 	 */
550 	if (link->irq.active)
551 		irq = link->irq.active;
552 	else
553 		irq = link->irq.possible[link->irq.possible_count - 1];
554 
555 	if (acpi_irq_balance || !link->irq.active) {
556 		/*
557 		 * Select the best IRQ.  This is done in reverse to promote
558 		 * the use of IRQs 9, 10, 11, and >15.
559 		 */
560 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
561 			if (acpi_irq_penalty[irq] >
562 			    acpi_irq_penalty[link->irq.possible[i]])
563 				irq = link->irq.possible[i];
564 		}
565 	}
566 
567 	/* Attempt to enable the link device at this IRQ. */
568 	if (acpi_pci_link_set(link, irq)) {
569 		printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
570 			    "Try pci=noacpi or acpi=off\n",
571 			    acpi_device_name(link->device),
572 			    acpi_device_bid(link->device));
573 		return -ENODEV;
574 	} else {
575 		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
576 		printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
577 		       acpi_device_name(link->device),
578 		       acpi_device_bid(link->device), link->irq.active);
579 	}
580 
581 	link->irq.initialized = 1;
582 	return 0;
583 }
584 
585 /*
586  * acpi_pci_link_allocate_irq
587  * success: return IRQ >= 0
588  * failure: return -1
589  */
590 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
591 			       int *polarity, char **name)
592 {
593 	int result;
594 	struct acpi_device *device;
595 	struct acpi_pci_link *link;
596 
597 	result = acpi_bus_get_device(handle, &device);
598 	if (result) {
599 		printk(KERN_ERR PREFIX "Invalid link device\n");
600 		return -1;
601 	}
602 
603 	link = acpi_driver_data(device);
604 	if (!link) {
605 		printk(KERN_ERR PREFIX "Invalid link context\n");
606 		return -1;
607 	}
608 
609 	/* TBD: Support multiple index (IRQ) entries per Link Device */
610 	if (index) {
611 		printk(KERN_ERR PREFIX "Invalid index %d\n", index);
612 		return -1;
613 	}
614 
615 	mutex_lock(&acpi_link_lock);
616 	if (acpi_pci_link_allocate(link)) {
617 		mutex_unlock(&acpi_link_lock);
618 		return -1;
619 	}
620 
621 	if (!link->irq.active) {
622 		mutex_unlock(&acpi_link_lock);
623 		printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
624 		return -1;
625 	}
626 	link->refcnt++;
627 	mutex_unlock(&acpi_link_lock);
628 
629 	if (triggering)
630 		*triggering = link->irq.triggering;
631 	if (polarity)
632 		*polarity = link->irq.polarity;
633 	if (name)
634 		*name = acpi_device_bid(link->device);
635 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
636 			  "Link %s is referenced\n",
637 			  acpi_device_bid(link->device)));
638 	return (link->irq.active);
639 }
640 
641 /*
642  * We don't change link's irq information here.  After it is reenabled, we
643  * continue use the info
644  */
645 int acpi_pci_link_free_irq(acpi_handle handle)
646 {
647 	struct acpi_device *device;
648 	struct acpi_pci_link *link;
649 	acpi_status result;
650 
651 	result = acpi_bus_get_device(handle, &device);
652 	if (result) {
653 		printk(KERN_ERR PREFIX "Invalid link device\n");
654 		return -1;
655 	}
656 
657 	link = acpi_driver_data(device);
658 	if (!link) {
659 		printk(KERN_ERR PREFIX "Invalid link context\n");
660 		return -1;
661 	}
662 
663 	mutex_lock(&acpi_link_lock);
664 	if (!link->irq.initialized) {
665 		mutex_unlock(&acpi_link_lock);
666 		printk(KERN_ERR PREFIX "Link isn't initialized\n");
667 		return -1;
668 	}
669 #ifdef	FUTURE_USE
670 	/*
671 	 * The Link reference count allows us to _DISable an unused link
672 	 * and suspend time, and set it again  on resume.
673 	 * However, 2.6.12 still has irq_router.resume
674 	 * which blindly restores the link state.
675 	 * So we disable the reference count method
676 	 * to prevent duplicate acpi_pci_link_set()
677 	 * which would harm some systems
678 	 */
679 	link->refcnt--;
680 #endif
681 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
682 			  "Link %s is dereferenced\n",
683 			  acpi_device_bid(link->device)));
684 
685 	if (link->refcnt == 0)
686 		acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
687 
688 	mutex_unlock(&acpi_link_lock);
689 	return (link->irq.active);
690 }
691 
692 /* --------------------------------------------------------------------------
693                                  Driver Interface
694    -------------------------------------------------------------------------- */
695 
696 static int acpi_pci_link_add(struct acpi_device *device)
697 {
698 	int result;
699 	struct acpi_pci_link *link;
700 	int i;
701 	int found = 0;
702 
703 	link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
704 	if (!link)
705 		return -ENOMEM;
706 
707 	link->device = device;
708 	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
709 	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
710 	device->driver_data = link;
711 
712 	mutex_lock(&acpi_link_lock);
713 	result = acpi_pci_link_get_possible(link);
714 	if (result)
715 		goto end;
716 
717 	/* query and set link->irq.active */
718 	acpi_pci_link_get_current(link);
719 
720 	printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
721 	       acpi_device_bid(device));
722 	for (i = 0; i < link->irq.possible_count; i++) {
723 		if (link->irq.active == link->irq.possible[i]) {
724 			printk(" *%d", link->irq.possible[i]);
725 			found = 1;
726 		} else
727 			printk(" %d", link->irq.possible[i]);
728 	}
729 
730 	printk(")");
731 
732 	if (!found)
733 		printk(" *%d", link->irq.active);
734 
735 	if (!link->device->status.enabled)
736 		printk(", disabled.");
737 
738 	printk("\n");
739 
740 	list_add_tail(&link->list, &acpi_link_list);
741 
742       end:
743 	/* disable all links -- to be activated on use */
744 	acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
745 	mutex_unlock(&acpi_link_lock);
746 
747 	if (result)
748 		kfree(link);
749 
750 	return result;
751 }
752 
753 static int acpi_pci_link_resume(struct acpi_pci_link *link)
754 {
755 	if (link->refcnt && link->irq.active && link->irq.initialized)
756 		return (acpi_pci_link_set(link, link->irq.active));
757 
758 	return 0;
759 }
760 
761 static int irqrouter_resume(struct sys_device *dev)
762 {
763 	struct acpi_pci_link *link;
764 
765 	list_for_each_entry(link, &acpi_link_list, list) {
766 		acpi_pci_link_resume(link);
767 	}
768 	return 0;
769 }
770 
771 static int acpi_pci_link_remove(struct acpi_device *device, int type)
772 {
773 	struct acpi_pci_link *link;
774 
775 	link = acpi_driver_data(device);
776 
777 	mutex_lock(&acpi_link_lock);
778 	list_del(&link->list);
779 	mutex_unlock(&acpi_link_lock);
780 
781 	kfree(link);
782 	return 0;
783 }
784 
785 /*
786  * modify acpi_irq_penalty[] from cmdline
787  */
788 static int __init acpi_irq_penalty_update(char *str, int used)
789 {
790 	int i;
791 
792 	for (i = 0; i < 16; i++) {
793 		int retval;
794 		int irq;
795 
796 		retval = get_option(&str, &irq);
797 
798 		if (!retval)
799 			break;	/* no number found */
800 
801 		if (irq < 0)
802 			continue;
803 
804 		if (irq >= ARRAY_SIZE(acpi_irq_penalty))
805 			continue;
806 
807 		if (used)
808 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
809 		else
810 			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
811 
812 		if (retval != 2)	/* no next number */
813 			break;
814 	}
815 	return 1;
816 }
817 
818 /*
819  * We'd like PNP to call this routine for the
820  * single ISA_USED value for each legacy device.
821  * But instead it calls us with each POSSIBLE setting.
822  * There is no ISA_POSSIBLE weight, so we simply use
823  * the (small) PCI_USING penalty.
824  */
825 void acpi_penalize_isa_irq(int irq, int active)
826 {
827 	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
828 		if (active)
829 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
830 		else
831 			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
832 	}
833 }
834 
835 /*
836  * Over-ride default table to reserve additional IRQs for use by ISA
837  * e.g. acpi_irq_isa=5
838  * Useful for telling ACPI how not to interfere with your ISA sound card.
839  */
840 static int __init acpi_irq_isa(char *str)
841 {
842 	return acpi_irq_penalty_update(str, 1);
843 }
844 
845 __setup("acpi_irq_isa=", acpi_irq_isa);
846 
847 /*
848  * Over-ride default table to free additional IRQs for use by PCI
849  * e.g. acpi_irq_pci=7,15
850  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
851  */
852 static int __init acpi_irq_pci(char *str)
853 {
854 	return acpi_irq_penalty_update(str, 0);
855 }
856 
857 __setup("acpi_irq_pci=", acpi_irq_pci);
858 
859 static int __init acpi_irq_nobalance_set(char *str)
860 {
861 	acpi_irq_balance = 0;
862 	return 1;
863 }
864 
865 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
866 
867 static int __init acpi_irq_balance_set(char *str)
868 {
869 	acpi_irq_balance = 1;
870 	return 1;
871 }
872 
873 __setup("acpi_irq_balance", acpi_irq_balance_set);
874 
875 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
876 static struct sysdev_class irqrouter_sysdev_class = {
877 	.name = "irqrouter",
878 	.resume = irqrouter_resume,
879 };
880 
881 static struct sys_device device_irqrouter = {
882 	.id = 0,
883 	.cls = &irqrouter_sysdev_class,
884 };
885 
886 static int __init irqrouter_init_sysfs(void)
887 {
888 	int error;
889 
890 	if (acpi_disabled || acpi_noirq)
891 		return 0;
892 
893 	error = sysdev_class_register(&irqrouter_sysdev_class);
894 	if (!error)
895 		error = sysdev_register(&device_irqrouter);
896 
897 	return error;
898 }
899 
900 device_initcall(irqrouter_init_sysfs);
901 
902 static int __init acpi_pci_link_init(void)
903 {
904 	if (acpi_noirq)
905 		return 0;
906 
907 	if (acpi_irq_balance == -1) {
908 		/* no command line switch: enable balancing in IOAPIC mode */
909 		if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
910 			acpi_irq_balance = 1;
911 		else
912 			acpi_irq_balance = 0;
913 	}
914 
915 	if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
916 		return -ENODEV;
917 
918 	return 0;
919 }
920 
921 subsys_initcall(acpi_pci_link_init);
922