xref: /linux/drivers/acpi/pci_link.c (revision b0148a98ec5151fec82064d95f11eb9efbc628ea)
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_HID		"PNP0C0F"
50 #define ACPI_PCI_LINK_DRIVER_NAME	"ACPI PCI Interrupt Link Driver"
51 #define ACPI_PCI_LINK_DEVICE_NAME	"PCI Interrupt Link"
52 #define ACPI_PCI_LINK_FILE_INFO		"info"
53 #define ACPI_PCI_LINK_FILE_STATUS	"state"
54 #define ACPI_PCI_LINK_MAX_POSSIBLE 16
55 static int acpi_pci_link_add(struct acpi_device *device);
56 static int acpi_pci_link_remove(struct acpi_device *device, int type);
57 
58 static struct acpi_driver acpi_pci_link_driver = {
59 	.name = ACPI_PCI_LINK_DRIVER_NAME,
60 	.class = ACPI_PCI_LINK_CLASS,
61 	.ids = ACPI_PCI_LINK_HID,
62 	.ops = {
63 		.add = acpi_pci_link_add,
64 		.remove = acpi_pci_link_remove,
65 		},
66 };
67 
68 /*
69  * If a link is initialized, we never change its active and initialized
70  * later even the link is disable. Instead, we just repick the active irq
71  */
72 struct acpi_pci_link_irq {
73 	u8 active;		/* Current IRQ */
74 	u8 triggering;		/* All IRQs */
75 	u8 polarity;	/* All IRQs */
76 	u8 resource_type;
77 	u8 possible_count;
78 	u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
79 	u8 initialized:1;
80 	u8 reserved:7;
81 };
82 
83 struct acpi_pci_link {
84 	struct list_head node;
85 	struct acpi_device *device;
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 DEFINE_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 = context;
107 	u32 i = 0;
108 
109 
110 	switch (resource->type) {
111 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
112 		return AE_OK;
113 	case ACPI_RESOURCE_TYPE_IRQ:
114 		{
115 			struct acpi_resource_irq *p = &resource->data.irq;
116 			if (!p || !p->interrupt_count) {
117 				printk(KERN_WARNING PREFIX "Blank IRQ resource\n");
118 				return AE_OK;
119 			}
120 			for (i = 0;
121 			     (i < p->interrupt_count
122 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
123 				if (!p->interrupts[i]) {
124 					printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
125 						      p->interrupts[i]);
126 					continue;
127 				}
128 				link->irq.possible[i] = p->interrupts[i];
129 				link->irq.possible_count++;
130 			}
131 			link->irq.triggering = p->triggering;
132 			link->irq.polarity = p->polarity;
133 			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
134 			break;
135 		}
136 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
137 		{
138 			struct acpi_resource_extended_irq *p =
139 			    &resource->data.extended_irq;
140 			if (!p || !p->interrupt_count) {
141 				printk(KERN_WARNING PREFIX
142 					      "Blank EXT IRQ resource\n");
143 				return AE_OK;
144 			}
145 			for (i = 0;
146 			     (i < p->interrupt_count
147 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
148 				if (!p->interrupts[i]) {
149 					printk(KERN_WARNING PREFIX "Invalid IRQ %d\n",
150 						      p->interrupts[i]);
151 					continue;
152 				}
153 				link->irq.possible[i] = p->interrupts[i];
154 				link->irq.possible_count++;
155 			}
156 			link->irq.triggering = p->triggering;
157 			link->irq.polarity = p->polarity;
158 			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
159 			break;
160 		}
161 	default:
162 		printk(KERN_ERR PREFIX "Resource is not an IRQ entry\n");
163 		return AE_OK;
164 	}
165 
166 	return AE_CTRL_TERMINATE;
167 }
168 
169 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
170 {
171 	acpi_status status;
172 
173 
174 	if (!link)
175 		return -EINVAL;
176 
177 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
178 				     acpi_pci_link_check_possible, link);
179 	if (ACPI_FAILURE(status)) {
180 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
181 		return -ENODEV;
182 	}
183 
184 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
185 			  "Found %d possible IRQs\n",
186 			  link->irq.possible_count));
187 
188 	return 0;
189 }
190 
191 static acpi_status
192 acpi_pci_link_check_current(struct acpi_resource *resource, void *context)
193 {
194 	int *irq = (int *)context;
195 
196 
197 	switch (resource->type) {
198 	case ACPI_RESOURCE_TYPE_IRQ:
199 		{
200 			struct acpi_resource_irq *p = &resource->data.irq;
201 			if (!p || !p->interrupt_count) {
202 				/*
203 				 * IRQ descriptors may have no IRQ# bits set,
204 				 * particularly those those w/ _STA disabled
205 				 */
206 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
207 						  "Blank IRQ resource\n"));
208 				return AE_OK;
209 			}
210 			*irq = p->interrupts[0];
211 			break;
212 		}
213 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
214 		{
215 			struct acpi_resource_extended_irq *p =
216 			    &resource->data.extended_irq;
217 			if (!p || !p->interrupt_count) {
218 				/*
219 				 * extended IRQ descriptors must
220 				 * return at least 1 IRQ
221 				 */
222 				printk(KERN_WARNING PREFIX
223 					      "Blank EXT IRQ resource\n");
224 				return AE_OK;
225 			}
226 			*irq = p->interrupts[0];
227 			break;
228 		}
229 		break;
230 	default:
231 		printk(KERN_ERR PREFIX "Resource %d isn't an IRQ\n", resource->type);
232 	case ACPI_RESOURCE_TYPE_END_TAG:
233 		return AE_OK;
234 	}
235 	return AE_CTRL_TERMINATE;
236 }
237 
238 /*
239  * Run _CRS and set link->irq.active
240  *
241  * return value:
242  * 0 - success
243  * !0 - failure
244  */
245 static int acpi_pci_link_get_current(struct acpi_pci_link *link)
246 {
247 	int result = 0;
248 	acpi_status status = AE_OK;
249 	int irq = 0;
250 
251 	if (!link)
252 		return -EINVAL;
253 
254 	link->irq.active = 0;
255 
256 	/* in practice, status disabled is meaningless, ignore it */
257 	if (acpi_strict) {
258 		/* Query _STA, set link->device->status */
259 		result = acpi_bus_get_status(link->device);
260 		if (result) {
261 			printk(KERN_ERR PREFIX "Unable to read status\n");
262 			goto end;
263 		}
264 
265 		if (!link->device->status.enabled) {
266 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
267 			return 0;
268 		}
269 	}
270 
271 	/*
272 	 * Query and parse _CRS to get the current IRQ assignment.
273 	 */
274 
275 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
276 				     acpi_pci_link_check_current, &irq);
277 	if (ACPI_FAILURE(status)) {
278 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
279 		result = -ENODEV;
280 		goto end;
281 	}
282 
283 	if (acpi_strict && !irq) {
284 		printk(KERN_ERR PREFIX "_CRS returned 0\n");
285 		result = -ENODEV;
286 	}
287 
288 	link->irq.active = irq;
289 
290 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
291 
292       end:
293 	return result;
294 }
295 
296 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
297 {
298 	int result = 0;
299 	acpi_status status = AE_OK;
300 	struct {
301 		struct acpi_resource res;
302 		struct acpi_resource end;
303 	} *resource;
304 	struct acpi_buffer buffer = { 0, NULL };
305 
306 
307 	if (!link || !irq)
308 		return -EINVAL;
309 
310 	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
311 	if (!resource)
312 		return -ENOMEM;
313 
314 	buffer.length = sizeof(*resource) + 1;
315 	buffer.pointer = resource;
316 
317 	switch (link->irq.resource_type) {
318 	case ACPI_RESOURCE_TYPE_IRQ:
319 		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
320 		resource->res.length = sizeof(struct acpi_resource);
321 		resource->res.data.irq.triggering = link->irq.triggering;
322 		resource->res.data.irq.polarity =
323 		    link->irq.polarity;
324 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
325 			resource->res.data.irq.sharable =
326 			    ACPI_EXCLUSIVE;
327 		else
328 			resource->res.data.irq.sharable = ACPI_SHARED;
329 		resource->res.data.irq.interrupt_count = 1;
330 		resource->res.data.irq.interrupts[0] = irq;
331 		break;
332 
333 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
334 		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
335 		resource->res.length = sizeof(struct acpi_resource);
336 		resource->res.data.extended_irq.producer_consumer =
337 		    ACPI_CONSUMER;
338 		resource->res.data.extended_irq.triggering =
339 		    link->irq.triggering;
340 		resource->res.data.extended_irq.polarity =
341 		    link->irq.polarity;
342 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
343 			resource->res.data.irq.sharable =
344 			    ACPI_EXCLUSIVE;
345 		else
346 			resource->res.data.irq.sharable = ACPI_SHARED;
347 		resource->res.data.extended_irq.interrupt_count = 1;
348 		resource->res.data.extended_irq.interrupts[0] = irq;
349 		/* ignore resource_source, it's optional */
350 		break;
351 	default:
352 		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
353 		result = -EINVAL;
354 		goto end;
355 
356 	}
357 	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
358 
359 	/* Attempt to set the resource */
360 	status = acpi_set_current_resources(link->device->handle, &buffer);
361 
362 	/* check for total failure */
363 	if (ACPI_FAILURE(status)) {
364 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
365 		result = -ENODEV;
366 		goto end;
367 	}
368 
369 	/* Query _STA, set device->status */
370 	result = acpi_bus_get_status(link->device);
371 	if (result) {
372 		printk(KERN_ERR PREFIX "Unable to read status\n");
373 		goto end;
374 	}
375 	if (!link->device->status.enabled) {
376 		printk(KERN_WARNING PREFIX
377 			      "%s [%s] disabled and referenced, BIOS bug\n",
378 			      acpi_device_name(link->device),
379 			      acpi_device_bid(link->device));
380 	}
381 
382 	/* Query _CRS, set link->irq.active */
383 	result = acpi_pci_link_get_current(link);
384 	if (result) {
385 		goto end;
386 	}
387 
388 	/*
389 	 * Is current setting not what we set?
390 	 * set link->irq.active
391 	 */
392 	if (link->irq.active != irq) {
393 		/*
394 		 * policy: when _CRS doesn't return what we just _SRS
395 		 * assume _SRS worked and override _CRS value.
396 		 */
397 		printk(KERN_WARNING PREFIX
398 			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
399 			      acpi_device_name(link->device),
400 			      acpi_device_bid(link->device), link->irq.active, irq);
401 		link->irq.active = irq;
402 	}
403 
404 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
405 
406       end:
407 	kfree(resource);
408 	return result;
409 }
410 
411 /* --------------------------------------------------------------------------
412                             PCI Link IRQ Management
413    -------------------------------------------------------------------------- */
414 
415 /*
416  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
417  * Link Devices to move the PIRQs around to minimize sharing.
418  *
419  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
420  * that the BIOS has already set to active.  This is necessary because
421  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
422  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
423  * even if acpi_irq_nobalance is set.
424  *
425  * A tables of penalties avoids directing PCI interrupts to well known
426  * ISA IRQs. Boot params are available to over-ride the default table:
427  *
428  * List interrupts that are free for PCI use.
429  * acpi_irq_pci=n[,m]
430  *
431  * List interrupts that should not be used for PCI:
432  * acpi_irq_isa=n[,m]
433  *
434  * Note that PCI IRQ routers have a list of possible IRQs,
435  * which may not include the IRQs this table says are available.
436  *
437  * Since this heuristic can't tell the difference between a link
438  * that no device will attach to, vs. a link which may be shared
439  * by multiple active devices -- it is not optimal.
440  *
441  * If interrupt performance is that important, get an IO-APIC system
442  * with a pin dedicated to each device.  Or for that matter, an MSI
443  * enabled system.
444  */
445 
446 #define ACPI_MAX_IRQS		256
447 #define ACPI_MAX_ISA_IRQ	16
448 
449 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
450 #define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
451 #define PIRQ_PENALTY_PCI_USING		(16*16*16)
452 #define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
453 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
454 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
455 
456 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
457 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
458 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
459 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
460 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
461 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
462 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
463 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
464 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
465 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
466 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
467 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
468 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
469 	PIRQ_PENALTY_ISA_USED,	/* IRQ12 mouse */
470 	PIRQ_PENALTY_ISA_USED,	/* IRQ13 fpe, sometimes */
471 	PIRQ_PENALTY_ISA_USED,	/* IRQ14 ide0 */
472 	PIRQ_PENALTY_ISA_USED,	/* IRQ15 ide1 */
473 	/* >IRQ15 */
474 };
475 
476 int __init acpi_irq_penalty_init(void)
477 {
478 	struct list_head *node = NULL;
479 	struct acpi_pci_link *link = NULL;
480 	int i = 0;
481 
482 
483 	/*
484 	 * Update penalties to facilitate IRQ balancing.
485 	 */
486 	list_for_each(node, &acpi_link.entries) {
487 
488 		link = list_entry(node, struct acpi_pci_link, node);
489 		if (!link) {
490 			printk(KERN_ERR PREFIX "Invalid link context\n");
491 			continue;
492 		}
493 
494 		/*
495 		 * reflect the possible and active irqs in the penalty table --
496 		 * useful for breaking ties.
497 		 */
498 		if (link->irq.possible_count) {
499 			int penalty =
500 			    PIRQ_PENALTY_PCI_POSSIBLE /
501 			    link->irq.possible_count;
502 
503 			for (i = 0; i < link->irq.possible_count; i++) {
504 				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
505 					acpi_irq_penalty[link->irq.
506 							 possible[i]] +=
507 					    penalty;
508 			}
509 
510 		} else if (link->irq.active) {
511 			acpi_irq_penalty[link->irq.active] +=
512 			    PIRQ_PENALTY_PCI_POSSIBLE;
513 		}
514 	}
515 	/* Add a penalty for the SCI */
516 	acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
517 
518 	return 0;
519 }
520 
521 static int acpi_irq_balance;	/* 0: static, 1: balance */
522 
523 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
524 {
525 	int irq;
526 	int i;
527 
528 
529 	if (link->irq.initialized) {
530 		if (link->refcnt == 0)
531 			/* This means the link is disabled but initialized */
532 			acpi_pci_link_set(link, link->irq.active);
533 		return 0;
534 	}
535 
536 	/*
537 	 * search for active IRQ in list of possible IRQs.
538 	 */
539 	for (i = 0; i < link->irq.possible_count; ++i) {
540 		if (link->irq.active == link->irq.possible[i])
541 			break;
542 	}
543 	/*
544 	 * forget active IRQ that is not in possible list
545 	 */
546 	if (i == link->irq.possible_count) {
547 		if (acpi_strict)
548 			printk(KERN_WARNING PREFIX "_CRS %d not found"
549 				      " in _PRS\n", link->irq.active);
550 		link->irq.active = 0;
551 	}
552 
553 	/*
554 	 * if active found, use it; else pick entry from end of possible list.
555 	 */
556 	if (link->irq.active) {
557 		irq = link->irq.active;
558 	} else {
559 		irq = link->irq.possible[link->irq.possible_count - 1];
560 	}
561 
562 	if (acpi_irq_balance || !link->irq.active) {
563 		/*
564 		 * Select the best IRQ.  This is done in reverse to promote
565 		 * the use of IRQs 9, 10, 11, and >15.
566 		 */
567 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
568 			if (acpi_irq_penalty[irq] >
569 			    acpi_irq_penalty[link->irq.possible[i]])
570 				irq = link->irq.possible[i];
571 		}
572 	}
573 
574 	/* Attempt to enable the link device at this IRQ. */
575 	if (acpi_pci_link_set(link, irq)) {
576 		printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
577 			    "Try pci=noacpi or acpi=off\n",
578 			    acpi_device_name(link->device),
579 			    acpi_device_bid(link->device));
580 		return -ENODEV;
581 	} else {
582 		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
583 		printk(PREFIX "%s [%s] enabled at IRQ %d\n",
584 		       acpi_device_name(link->device),
585 		       acpi_device_bid(link->device), link->irq.active);
586 	}
587 
588 	link->irq.initialized = 1;
589 
590 	return 0;
591 }
592 
593 /*
594  * acpi_pci_link_allocate_irq
595  * success: return IRQ >= 0
596  * failure: return -1
597  */
598 
599 int
600 acpi_pci_link_allocate_irq(acpi_handle handle,
601 			   int index,
602 			   int *triggering, int *polarity, char **name)
603 {
604 	int result = 0;
605 	struct acpi_device *device = NULL;
606 	struct acpi_pci_link *link = NULL;
607 
608 
609 	result = acpi_bus_get_device(handle, &device);
610 	if (result) {
611 		printk(KERN_ERR PREFIX "Invalid link device\n");
612 		return -1;
613 	}
614 
615 	link = acpi_driver_data(device);
616 	if (!link) {
617 		printk(KERN_ERR PREFIX "Invalid link context\n");
618 		return -1;
619 	}
620 
621 	/* TBD: Support multiple index (IRQ) entries per Link Device */
622 	if (index) {
623 		printk(KERN_ERR PREFIX "Invalid index %d\n", index);
624 		return -1;
625 	}
626 
627 	mutex_lock(&acpi_link_lock);
628 	if (acpi_pci_link_allocate(link)) {
629 		mutex_unlock(&acpi_link_lock);
630 		return -1;
631 	}
632 
633 	if (!link->irq.active) {
634 		mutex_unlock(&acpi_link_lock);
635 		printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
636 		return -1;
637 	}
638 	link->refcnt++;
639 	mutex_unlock(&acpi_link_lock);
640 
641 	if (triggering)
642 		*triggering = link->irq.triggering;
643 	if (polarity)
644 		*polarity = link->irq.polarity;
645 	if (name)
646 		*name = acpi_device_bid(link->device);
647 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
648 			  "Link %s is referenced\n",
649 			  acpi_device_bid(link->device)));
650 	return (link->irq.active);
651 }
652 
653 /*
654  * We don't change link's irq information here.  After it is reenabled, we
655  * continue use the info
656  */
657 int acpi_pci_link_free_irq(acpi_handle handle)
658 {
659 	struct acpi_device *device = NULL;
660 	struct acpi_pci_link *link = NULL;
661 	acpi_status result;
662 
663 
664 	result = acpi_bus_get_device(handle, &device);
665 	if (result) {
666 		printk(KERN_ERR PREFIX "Invalid link device\n");
667 		return -1;
668 	}
669 
670 	link = acpi_driver_data(device);
671 	if (!link) {
672 		printk(KERN_ERR PREFIX "Invalid link context\n");
673 		return -1;
674 	}
675 
676 	mutex_lock(&acpi_link_lock);
677 	if (!link->irq.initialized) {
678 		mutex_unlock(&acpi_link_lock);
679 		printk(KERN_ERR PREFIX "Link isn't initialized\n");
680 		return -1;
681 	}
682 #ifdef	FUTURE_USE
683 	/*
684 	 * The Link reference count allows us to _DISable an unused link
685 	 * and suspend time, and set it again  on resume.
686 	 * However, 2.6.12 still has irq_router.resume
687 	 * which blindly restores the link state.
688 	 * So we disable the reference count method
689 	 * to prevent duplicate acpi_pci_link_set()
690 	 * which would harm some systems
691 	 */
692 	link->refcnt--;
693 #endif
694 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
695 			  "Link %s is dereferenced\n",
696 			  acpi_device_bid(link->device)));
697 
698 	if (link->refcnt == 0) {
699 		acpi_ut_evaluate_object(link->device->handle, "_DIS", 0, NULL);
700 	}
701 	mutex_unlock(&acpi_link_lock);
702 	return (link->irq.active);
703 }
704 
705 /* --------------------------------------------------------------------------
706                                  Driver Interface
707    -------------------------------------------------------------------------- */
708 
709 static int acpi_pci_link_add(struct acpi_device *device)
710 {
711 	int result = 0;
712 	struct acpi_pci_link *link = NULL;
713 	int i = 0;
714 	int found = 0;
715 
716 
717 	if (!device)
718 		return -EINVAL;
719 
720 	link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
721 	if (!link)
722 		return -ENOMEM;
723 
724 	link->device = device;
725 	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
726 	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
727 	acpi_driver_data(device) = link;
728 
729 	mutex_lock(&acpi_link_lock);
730 	result = acpi_pci_link_get_possible(link);
731 	if (result)
732 		goto end;
733 
734 	/* query and set link->irq.active */
735 	acpi_pci_link_get_current(link);
736 
737 	printk(PREFIX "%s [%s] (IRQs", acpi_device_name(device),
738 	       acpi_device_bid(device));
739 	for (i = 0; i < link->irq.possible_count; i++) {
740 		if (link->irq.active == link->irq.possible[i]) {
741 			printk(" *%d", link->irq.possible[i]);
742 			found = 1;
743 		} else
744 			printk(" %d", link->irq.possible[i]);
745 	}
746 
747 	printk(")");
748 
749 	if (!found)
750 		printk(" *%d", link->irq.active);
751 
752 	if (!link->device->status.enabled)
753 		printk(", disabled.");
754 
755 	printk("\n");
756 
757 	/* TBD: Acquire/release lock */
758 	list_add_tail(&link->node, &acpi_link.entries);
759 	acpi_link.count++;
760 
761       end:
762 	/* disable all links -- to be activated on use */
763 	acpi_ut_evaluate_object(device->handle, "_DIS", 0, NULL);
764 	mutex_unlock(&acpi_link_lock);
765 
766 	if (result)
767 		kfree(link);
768 
769 	return result;
770 }
771 
772 static int acpi_pci_link_resume(struct acpi_pci_link *link)
773 {
774 
775 	if (link->refcnt && link->irq.active && link->irq.initialized)
776 		return (acpi_pci_link_set(link, link->irq.active));
777 	else
778 		return 0;
779 }
780 
781 static int irqrouter_resume(struct sys_device *dev)
782 {
783 	struct list_head *node = NULL;
784 	struct acpi_pci_link *link = NULL;
785 
786 
787 	/* Make sure SCI is enabled again (Apple firmware bug?) */
788 	acpi_set_register(ACPI_BITREG_SCI_ENABLE, 1);
789 
790 	list_for_each(node, &acpi_link.entries) {
791 		link = list_entry(node, struct acpi_pci_link, node);
792 		if (!link) {
793 			printk(KERN_ERR PREFIX "Invalid link context\n");
794 			continue;
795 		}
796 		acpi_pci_link_resume(link);
797 	}
798 	return 0;
799 }
800 
801 static int acpi_pci_link_remove(struct acpi_device *device, int type)
802 {
803 	struct acpi_pci_link *link = NULL;
804 
805 
806 	if (!device || !acpi_driver_data(device))
807 		return -EINVAL;
808 
809 	link = acpi_driver_data(device);
810 
811 	mutex_lock(&acpi_link_lock);
812 	list_del(&link->node);
813 	mutex_unlock(&acpi_link_lock);
814 
815 	kfree(link);
816 
817 	return 0;
818 }
819 
820 /*
821  * modify acpi_irq_penalty[] from cmdline
822  */
823 static int __init acpi_irq_penalty_update(char *str, int used)
824 {
825 	int i;
826 
827 	for (i = 0; i < 16; i++) {
828 		int retval;
829 		int irq;
830 
831 		retval = get_option(&str, &irq);
832 
833 		if (!retval)
834 			break;	/* no number found */
835 
836 		if (irq < 0)
837 			continue;
838 
839 		if (irq >= ACPI_MAX_IRQS)
840 			continue;
841 
842 		if (used)
843 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
844 		else
845 			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
846 
847 		if (retval != 2)	/* no next number */
848 			break;
849 	}
850 	return 1;
851 }
852 
853 /*
854  * We'd like PNP to call this routine for the
855  * single ISA_USED value for each legacy device.
856  * But instead it calls us with each POSSIBLE setting.
857  * There is no ISA_POSSIBLE weight, so we simply use
858  * the (small) PCI_USING penalty.
859  */
860 void acpi_penalize_isa_irq(int irq, int active)
861 {
862 	if (active)
863 		acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
864 	else
865 		acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
866 }
867 
868 /*
869  * Over-ride default table to reserve additional IRQs for use by ISA
870  * e.g. acpi_irq_isa=5
871  * Useful for telling ACPI how not to interfere with your ISA sound card.
872  */
873 static int __init acpi_irq_isa(char *str)
874 {
875 	return acpi_irq_penalty_update(str, 1);
876 }
877 
878 __setup("acpi_irq_isa=", acpi_irq_isa);
879 
880 /*
881  * Over-ride default table to free additional IRQs for use by PCI
882  * e.g. acpi_irq_pci=7,15
883  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
884  */
885 static int __init acpi_irq_pci(char *str)
886 {
887 	return acpi_irq_penalty_update(str, 0);
888 }
889 
890 __setup("acpi_irq_pci=", acpi_irq_pci);
891 
892 static int __init acpi_irq_nobalance_set(char *str)
893 {
894 	acpi_irq_balance = 0;
895 	return 1;
896 }
897 
898 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
899 
900 int __init acpi_irq_balance_set(char *str)
901 {
902 	acpi_irq_balance = 1;
903 	return 1;
904 }
905 
906 __setup("acpi_irq_balance", acpi_irq_balance_set);
907 
908 /* FIXME: we will remove this interface after all drivers call pci_disable_device */
909 static struct sysdev_class irqrouter_sysdev_class = {
910 	set_kset_name("irqrouter"),
911 	.resume = irqrouter_resume,
912 };
913 
914 static struct sys_device device_irqrouter = {
915 	.id = 0,
916 	.cls = &irqrouter_sysdev_class,
917 };
918 
919 static int __init irqrouter_init_sysfs(void)
920 {
921 	int error;
922 
923 
924 	if (acpi_disabled || acpi_noirq)
925 		return 0;
926 
927 	error = sysdev_class_register(&irqrouter_sysdev_class);
928 	if (!error)
929 		error = sysdev_register(&device_irqrouter);
930 
931 	return error;
932 }
933 
934 device_initcall(irqrouter_init_sysfs);
935 
936 static int __init acpi_pci_link_init(void)
937 {
938 
939 	if (acpi_noirq)
940 		return 0;
941 
942 	acpi_link.count = 0;
943 	INIT_LIST_HEAD(&acpi_link.entries);
944 
945 	if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
946 		return -ENODEV;
947 
948 	return 0;
949 }
950 
951 subsys_initcall(acpi_pci_link_init);
952