xref: /openbmc/linux/drivers/acpi/pci_link.c (revision 95e9fd10)
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/syscore_ops.h>
33 #include <linux/kernel.h>
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/spinlock.h>
38 #include <linux/pm.h>
39 #include <linux/pci.h>
40 #include <linux/mutex.h>
41 #include <linux/slab.h>
42 
43 #include <acpi/acpi_bus.h>
44 #include <acpi/acpi_drivers.h>
45 
46 #define PREFIX "ACPI: "
47 
48 #define _COMPONENT			ACPI_PCI_COMPONENT
49 ACPI_MODULE_NAME("pci_link");
50 #define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
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 
56 static int acpi_pci_link_add(struct acpi_device *device);
57 static int acpi_pci_link_remove(struct acpi_device *device, int type);
58 
59 static const struct acpi_device_id link_device_ids[] = {
60 	{"PNP0C0F", 0},
61 	{"", 0},
62 };
63 MODULE_DEVICE_TABLE(acpi, link_device_ids);
64 
65 static struct acpi_driver acpi_pci_link_driver = {
66 	.name = "pci_link",
67 	.class = ACPI_PCI_LINK_CLASS,
68 	.ids = link_device_ids,
69 	.ops = {
70 		.add = acpi_pci_link_add,
71 		.remove = acpi_pci_link_remove,
72 	},
73 };
74 
75 /*
76  * If a link is initialized, we never change its active and initialized
77  * later even the link is disable. Instead, we just repick the active irq
78  */
79 struct acpi_pci_link_irq {
80 	u8 active;		/* Current IRQ */
81 	u8 triggering;		/* All IRQs */
82 	u8 polarity;		/* All IRQs */
83 	u8 resource_type;
84 	u8 possible_count;
85 	u8 possible[ACPI_PCI_LINK_MAX_POSSIBLE];
86 	u8 initialized:1;
87 	u8 reserved:7;
88 };
89 
90 struct acpi_pci_link {
91 	struct list_head		list;
92 	struct acpi_device		*device;
93 	struct acpi_pci_link_irq	irq;
94 	int				refcnt;
95 };
96 
97 static LIST_HEAD(acpi_link_list);
98 static DEFINE_MUTEX(acpi_link_lock);
99 
100 /* --------------------------------------------------------------------------
101                             PCI Link Device Management
102    -------------------------------------------------------------------------- */
103 
104 /*
105  * set context (link) possible list from resource list
106  */
107 static acpi_status acpi_pci_link_check_possible(struct acpi_resource *resource,
108 						void *context)
109 {
110 	struct acpi_pci_link *link = context;
111 	u32 i;
112 
113 	switch (resource->type) {
114 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
115 	case ACPI_RESOURCE_TYPE_END_TAG:
116 		return AE_OK;
117 	case ACPI_RESOURCE_TYPE_IRQ:
118 		{
119 			struct acpi_resource_irq *p = &resource->data.irq;
120 			if (!p || !p->interrupt_count) {
121 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
122 						  "Blank _PRS IRQ resource\n"));
123 				return AE_OK;
124 			}
125 			for (i = 0;
126 			     (i < p->interrupt_count
127 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
128 				if (!p->interrupts[i]) {
129 					printk(KERN_WARNING PREFIX
130 					       "Invalid _PRS IRQ %d\n",
131 					       p->interrupts[i]);
132 					continue;
133 				}
134 				link->irq.possible[i] = p->interrupts[i];
135 				link->irq.possible_count++;
136 			}
137 			link->irq.triggering = p->triggering;
138 			link->irq.polarity = p->polarity;
139 			link->irq.resource_type = ACPI_RESOURCE_TYPE_IRQ;
140 			break;
141 		}
142 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
143 		{
144 			struct acpi_resource_extended_irq *p =
145 			    &resource->data.extended_irq;
146 			if (!p || !p->interrupt_count) {
147 				printk(KERN_WARNING PREFIX
148 					      "Blank _PRS EXT IRQ resource\n");
149 				return AE_OK;
150 			}
151 			for (i = 0;
152 			     (i < p->interrupt_count
153 			      && i < ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
154 				if (!p->interrupts[i]) {
155 					printk(KERN_WARNING PREFIX
156 					       "Invalid _PRS IRQ %d\n",
157 					       p->interrupts[i]);
158 					continue;
159 				}
160 				link->irq.possible[i] = p->interrupts[i];
161 				link->irq.possible_count++;
162 			}
163 			link->irq.triggering = p->triggering;
164 			link->irq.polarity = p->polarity;
165 			link->irq.resource_type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
166 			break;
167 		}
168 	default:
169 		printk(KERN_ERR PREFIX "_PRS resource type 0x%x isn't an IRQ\n",
170 		       resource->type);
171 		return AE_OK;
172 	}
173 
174 	return AE_CTRL_TERMINATE;
175 }
176 
177 static int acpi_pci_link_get_possible(struct acpi_pci_link *link)
178 {
179 	acpi_status status;
180 
181 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__PRS,
182 				     acpi_pci_link_check_possible, link);
183 	if (ACPI_FAILURE(status)) {
184 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRS"));
185 		return -ENODEV;
186 	}
187 
188 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
189 			  "Found %d possible IRQs\n",
190 			  link->irq.possible_count));
191 
192 	return 0;
193 }
194 
195 static acpi_status acpi_pci_link_check_current(struct acpi_resource *resource,
196 					       void *context)
197 {
198 	int *irq = context;
199 
200 	switch (resource->type) {
201 	case ACPI_RESOURCE_TYPE_START_DEPENDENT:
202 	case ACPI_RESOURCE_TYPE_END_TAG:
203 		return AE_OK;
204 	case ACPI_RESOURCE_TYPE_IRQ:
205 		{
206 			struct acpi_resource_irq *p = &resource->data.irq;
207 			if (!p || !p->interrupt_count) {
208 				/*
209 				 * IRQ descriptors may have no IRQ# bits set,
210 				 * particularly those those w/ _STA disabled
211 				 */
212 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
213 						  "Blank _CRS IRQ resource\n"));
214 				return AE_OK;
215 			}
216 			*irq = p->interrupts[0];
217 			break;
218 		}
219 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
220 		{
221 			struct acpi_resource_extended_irq *p =
222 			    &resource->data.extended_irq;
223 			if (!p || !p->interrupt_count) {
224 				/*
225 				 * extended IRQ descriptors must
226 				 * return at least 1 IRQ
227 				 */
228 				printk(KERN_WARNING PREFIX
229 					      "Blank _CRS EXT IRQ resource\n");
230 				return AE_OK;
231 			}
232 			*irq = p->interrupts[0];
233 			break;
234 		}
235 		break;
236 	default:
237 		printk(KERN_ERR PREFIX "_CRS resource type 0x%x isn't an IRQ\n",
238 		       resource->type);
239 		return AE_OK;
240 	}
241 
242 	return 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;
256 	int irq = 0;
257 
258 	link->irq.active = 0;
259 
260 	/* in practice, status disabled is meaningless, ignore it */
261 	if (acpi_strict) {
262 		/* Query _STA, set link->device->status */
263 		result = acpi_bus_get_status(link->device);
264 		if (result) {
265 			printk(KERN_ERR PREFIX "Unable to read status\n");
266 			goto end;
267 		}
268 
269 		if (!link->device->status.enabled) {
270 			ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link disabled\n"));
271 			return 0;
272 		}
273 	}
274 
275 	/*
276 	 * Query and parse _CRS to get the current IRQ assignment.
277 	 */
278 
279 	status = acpi_walk_resources(link->device->handle, METHOD_NAME__CRS,
280 				     acpi_pci_link_check_current, &irq);
281 	if (ACPI_FAILURE(status)) {
282 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _CRS"));
283 		result = -ENODEV;
284 		goto end;
285 	}
286 
287 	if (acpi_strict && !irq) {
288 		printk(KERN_ERR PREFIX "_CRS returned 0\n");
289 		result = -ENODEV;
290 	}
291 
292 	link->irq.active = irq;
293 
294 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Link at IRQ %d \n", link->irq.active));
295 
296       end:
297 	return result;
298 }
299 
300 static int acpi_pci_link_set(struct acpi_pci_link *link, int irq)
301 {
302 	int result;
303 	acpi_status status;
304 	struct {
305 		struct acpi_resource res;
306 		struct acpi_resource end;
307 	} *resource;
308 	struct acpi_buffer buffer = { 0, NULL };
309 
310 	if (!irq)
311 		return -EINVAL;
312 
313 	resource = kzalloc(sizeof(*resource) + 1, irqs_disabled() ? GFP_ATOMIC: GFP_KERNEL);
314 	if (!resource)
315 		return -ENOMEM;
316 
317 	buffer.length = sizeof(*resource) + 1;
318 	buffer.pointer = resource;
319 
320 	switch (link->irq.resource_type) {
321 	case ACPI_RESOURCE_TYPE_IRQ:
322 		resource->res.type = ACPI_RESOURCE_TYPE_IRQ;
323 		resource->res.length = sizeof(struct acpi_resource);
324 		resource->res.data.irq.triggering = link->irq.triggering;
325 		resource->res.data.irq.polarity =
326 		    link->irq.polarity;
327 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
328 			resource->res.data.irq.sharable =
329 			    ACPI_EXCLUSIVE;
330 		else
331 			resource->res.data.irq.sharable = ACPI_SHARED;
332 		resource->res.data.irq.interrupt_count = 1;
333 		resource->res.data.irq.interrupts[0] = irq;
334 		break;
335 
336 	case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
337 		resource->res.type = ACPI_RESOURCE_TYPE_EXTENDED_IRQ;
338 		resource->res.length = sizeof(struct acpi_resource);
339 		resource->res.data.extended_irq.producer_consumer =
340 		    ACPI_CONSUMER;
341 		resource->res.data.extended_irq.triggering =
342 		    link->irq.triggering;
343 		resource->res.data.extended_irq.polarity =
344 		    link->irq.polarity;
345 		if (link->irq.triggering == ACPI_EDGE_SENSITIVE)
346 			resource->res.data.irq.sharable =
347 			    ACPI_EXCLUSIVE;
348 		else
349 			resource->res.data.irq.sharable = ACPI_SHARED;
350 		resource->res.data.extended_irq.interrupt_count = 1;
351 		resource->res.data.extended_irq.interrupts[0] = irq;
352 		/* ignore resource_source, it's optional */
353 		break;
354 	default:
355 		printk(KERN_ERR PREFIX "Invalid Resource_type %d\n", link->irq.resource_type);
356 		result = -EINVAL;
357 		goto end;
358 
359 	}
360 	resource->end.type = ACPI_RESOURCE_TYPE_END_TAG;
361 
362 	/* Attempt to set the resource */
363 	status = acpi_set_current_resources(link->device->handle, &buffer);
364 
365 	/* check for total failure */
366 	if (ACPI_FAILURE(status)) {
367 		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SRS"));
368 		result = -ENODEV;
369 		goto end;
370 	}
371 
372 	/* Query _STA, set device->status */
373 	result = acpi_bus_get_status(link->device);
374 	if (result) {
375 		printk(KERN_ERR PREFIX "Unable to read status\n");
376 		goto end;
377 	}
378 	if (!link->device->status.enabled) {
379 		printk(KERN_WARNING PREFIX
380 			      "%s [%s] disabled and referenced, BIOS bug\n",
381 			      acpi_device_name(link->device),
382 			      acpi_device_bid(link->device));
383 	}
384 
385 	/* Query _CRS, set link->irq.active */
386 	result = acpi_pci_link_get_current(link);
387 	if (result) {
388 		goto end;
389 	}
390 
391 	/*
392 	 * Is current setting not what we set?
393 	 * set link->irq.active
394 	 */
395 	if (link->irq.active != irq) {
396 		/*
397 		 * policy: when _CRS doesn't return what we just _SRS
398 		 * assume _SRS worked and override _CRS value.
399 		 */
400 		printk(KERN_WARNING PREFIX
401 			      "%s [%s] BIOS reported IRQ %d, using IRQ %d\n",
402 			      acpi_device_name(link->device),
403 			      acpi_device_bid(link->device), link->irq.active, irq);
404 		link->irq.active = irq;
405 	}
406 
407 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Set IRQ %d\n", link->irq.active));
408 
409       end:
410 	kfree(resource);
411 	return result;
412 }
413 
414 /* --------------------------------------------------------------------------
415                             PCI Link IRQ Management
416    -------------------------------------------------------------------------- */
417 
418 /*
419  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
420  * Link Devices to move the PIRQs around to minimize sharing.
421  *
422  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
423  * that the BIOS has already set to active.  This is necessary because
424  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
425  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
426  * even if acpi_irq_nobalance is set.
427  *
428  * A tables of penalties avoids directing PCI interrupts to well known
429  * ISA IRQs. Boot params are available to over-ride the default table:
430  *
431  * List interrupts that are free for PCI use.
432  * acpi_irq_pci=n[,m]
433  *
434  * List interrupts that should not be used for PCI:
435  * acpi_irq_isa=n[,m]
436  *
437  * Note that PCI IRQ routers have a list of possible IRQs,
438  * which may not include the IRQs this table says are available.
439  *
440  * Since this heuristic can't tell the difference between a link
441  * that no device will attach to, vs. a link which may be shared
442  * by multiple active devices -- it is not optimal.
443  *
444  * If interrupt performance is that important, get an IO-APIC system
445  * with a pin dedicated to each device.  Or for that matter, an MSI
446  * enabled system.
447  */
448 
449 #define ACPI_MAX_IRQS		256
450 #define ACPI_MAX_ISA_IRQ	16
451 
452 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
453 #define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
454 #define PIRQ_PENALTY_PCI_USING		(16*16*16)
455 #define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
456 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
457 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
458 
459 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
460 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
461 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
462 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
463 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3 serial */
464 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4 serial */
465 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
466 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
467 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
468 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
469 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
470 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
471 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
472 	PIRQ_PENALTY_ISA_USED,		/* IRQ12 mouse */
473 	PIRQ_PENALTY_ISA_USED,		/* IRQ13 fpe, sometimes */
474 	PIRQ_PENALTY_ISA_USED,		/* IRQ14 ide0 */
475 	PIRQ_PENALTY_ISA_USED,		/* IRQ15 ide1 */
476 	/* >IRQ15 */
477 };
478 
479 int __init acpi_irq_penalty_init(void)
480 {
481 	struct acpi_pci_link *link;
482 	int i;
483 
484 	/*
485 	 * Update penalties to facilitate IRQ balancing.
486 	 */
487 	list_for_each_entry(link, &acpi_link_list, list) {
488 
489 		/*
490 		 * reflect the possible and active irqs in the penalty table --
491 		 * useful for breaking ties.
492 		 */
493 		if (link->irq.possible_count) {
494 			int penalty =
495 			    PIRQ_PENALTY_PCI_POSSIBLE /
496 			    link->irq.possible_count;
497 
498 			for (i = 0; i < link->irq.possible_count; i++) {
499 				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
500 					acpi_irq_penalty[link->irq.
501 							 possible[i]] +=
502 					    penalty;
503 			}
504 
505 		} else if (link->irq.active) {
506 			acpi_irq_penalty[link->irq.active] +=
507 			    PIRQ_PENALTY_PCI_POSSIBLE;
508 		}
509 	}
510 	/* Add a penalty for the SCI */
511 	acpi_irq_penalty[acpi_gbl_FADT.sci_interrupt] += PIRQ_PENALTY_PCI_USING;
512 	return 0;
513 }
514 
515 static int acpi_irq_balance = -1;	/* 0: static, 1: balance */
516 
517 static int acpi_pci_link_allocate(struct acpi_pci_link *link)
518 {
519 	int irq;
520 	int i;
521 
522 	if (link->irq.initialized) {
523 		if (link->refcnt == 0)
524 			/* This means the link is disabled but initialized */
525 			acpi_pci_link_set(link, link->irq.active);
526 		return 0;
527 	}
528 
529 	/*
530 	 * search for active IRQ in list of possible IRQs.
531 	 */
532 	for (i = 0; i < link->irq.possible_count; ++i) {
533 		if (link->irq.active == link->irq.possible[i])
534 			break;
535 	}
536 	/*
537 	 * forget active IRQ that is not in possible list
538 	 */
539 	if (i == link->irq.possible_count) {
540 		if (acpi_strict)
541 			printk(KERN_WARNING PREFIX "_CRS %d not found"
542 				      " in _PRS\n", link->irq.active);
543 		link->irq.active = 0;
544 	}
545 
546 	/*
547 	 * if active found, use it; else pick entry from end of possible list.
548 	 */
549 	if (link->irq.active)
550 		irq = link->irq.active;
551 	else
552 		irq = link->irq.possible[link->irq.possible_count - 1];
553 
554 	if (acpi_irq_balance || !link->irq.active) {
555 		/*
556 		 * Select the best IRQ.  This is done in reverse to promote
557 		 * the use of IRQs 9, 10, 11, and >15.
558 		 */
559 		for (i = (link->irq.possible_count - 1); i >= 0; i--) {
560 			if (acpi_irq_penalty[irq] >
561 			    acpi_irq_penalty[link->irq.possible[i]])
562 				irq = link->irq.possible[i];
563 		}
564 	}
565 
566 	/* Attempt to enable the link device at this IRQ. */
567 	if (acpi_pci_link_set(link, irq)) {
568 		printk(KERN_ERR PREFIX "Unable to set IRQ for %s [%s]. "
569 			    "Try pci=noacpi or acpi=off\n",
570 			    acpi_device_name(link->device),
571 			    acpi_device_bid(link->device));
572 		return -ENODEV;
573 	} else {
574 		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
575 		printk(KERN_WARNING PREFIX "%s [%s] enabled at IRQ %d\n",
576 		       acpi_device_name(link->device),
577 		       acpi_device_bid(link->device), link->irq.active);
578 	}
579 
580 	link->irq.initialized = 1;
581 	return 0;
582 }
583 
584 /*
585  * acpi_pci_link_allocate_irq
586  * success: return IRQ >= 0
587  * failure: return -1
588  */
589 int acpi_pci_link_allocate_irq(acpi_handle handle, int index, int *triggering,
590 			       int *polarity, char **name)
591 {
592 	int result;
593 	struct acpi_device *device;
594 	struct acpi_pci_link *link;
595 
596 	result = acpi_bus_get_device(handle, &device);
597 	if (result) {
598 		printk(KERN_ERR PREFIX "Invalid link device\n");
599 		return -1;
600 	}
601 
602 	link = acpi_driver_data(device);
603 	if (!link) {
604 		printk(KERN_ERR PREFIX "Invalid link context\n");
605 		return -1;
606 	}
607 
608 	/* TBD: Support multiple index (IRQ) entries per Link Device */
609 	if (index) {
610 		printk(KERN_ERR PREFIX "Invalid index %d\n", index);
611 		return -1;
612 	}
613 
614 	mutex_lock(&acpi_link_lock);
615 	if (acpi_pci_link_allocate(link)) {
616 		mutex_unlock(&acpi_link_lock);
617 		return -1;
618 	}
619 
620 	if (!link->irq.active) {
621 		mutex_unlock(&acpi_link_lock);
622 		printk(KERN_ERR PREFIX "Link active IRQ is 0!\n");
623 		return -1;
624 	}
625 	link->refcnt++;
626 	mutex_unlock(&acpi_link_lock);
627 
628 	if (triggering)
629 		*triggering = link->irq.triggering;
630 	if (polarity)
631 		*polarity = link->irq.polarity;
632 	if (name)
633 		*name = acpi_device_bid(link->device);
634 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
635 			  "Link %s is referenced\n",
636 			  acpi_device_bid(link->device)));
637 	return (link->irq.active);
638 }
639 
640 /*
641  * We don't change link's irq information here.  After it is reenabled, we
642  * continue use the info
643  */
644 int acpi_pci_link_free_irq(acpi_handle handle)
645 {
646 	struct acpi_device *device;
647 	struct acpi_pci_link *link;
648 	acpi_status result;
649 
650 	result = acpi_bus_get_device(handle, &device);
651 	if (result) {
652 		printk(KERN_ERR PREFIX "Invalid link device\n");
653 		return -1;
654 	}
655 
656 	link = acpi_driver_data(device);
657 	if (!link) {
658 		printk(KERN_ERR PREFIX "Invalid link context\n");
659 		return -1;
660 	}
661 
662 	mutex_lock(&acpi_link_lock);
663 	if (!link->irq.initialized) {
664 		mutex_unlock(&acpi_link_lock);
665 		printk(KERN_ERR PREFIX "Link isn't initialized\n");
666 		return -1;
667 	}
668 #ifdef	FUTURE_USE
669 	/*
670 	 * The Link reference count allows us to _DISable an unused link
671 	 * and suspend time, and set it again  on resume.
672 	 * However, 2.6.12 still has irq_router.resume
673 	 * which blindly restores the link state.
674 	 * So we disable the reference count method
675 	 * to prevent duplicate acpi_pci_link_set()
676 	 * which would harm some systems
677 	 */
678 	link->refcnt--;
679 #endif
680 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
681 			  "Link %s is dereferenced\n",
682 			  acpi_device_bid(link->device)));
683 
684 	if (link->refcnt == 0)
685 		acpi_evaluate_object(link->device->handle, "_DIS", NULL, NULL);
686 
687 	mutex_unlock(&acpi_link_lock);
688 	return (link->irq.active);
689 }
690 
691 /* --------------------------------------------------------------------------
692                                  Driver Interface
693    -------------------------------------------------------------------------- */
694 
695 static int acpi_pci_link_add(struct acpi_device *device)
696 {
697 	int result;
698 	struct acpi_pci_link *link;
699 	int i;
700 	int found = 0;
701 
702 	link = kzalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
703 	if (!link)
704 		return -ENOMEM;
705 
706 	link->device = device;
707 	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
708 	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
709 	device->driver_data = link;
710 
711 	mutex_lock(&acpi_link_lock);
712 	result = acpi_pci_link_get_possible(link);
713 	if (result)
714 		goto end;
715 
716 	/* query and set link->irq.active */
717 	acpi_pci_link_get_current(link);
718 
719 	printk(KERN_INFO PREFIX "%s [%s] (IRQs", acpi_device_name(device),
720 	       acpi_device_bid(device));
721 	for (i = 0; i < link->irq.possible_count; i++) {
722 		if (link->irq.active == link->irq.possible[i]) {
723 			printk(KERN_CONT " *%d", link->irq.possible[i]);
724 			found = 1;
725 		} else
726 			printk(KERN_CONT " %d", link->irq.possible[i]);
727 	}
728 
729 	printk(KERN_CONT ")");
730 
731 	if (!found)
732 		printk(KERN_CONT " *%d", link->irq.active);
733 
734 	if (!link->device->status.enabled)
735 		printk(KERN_CONT ", disabled.");
736 
737 	printk(KERN_CONT "\n");
738 
739 	list_add_tail(&link->list, &acpi_link_list);
740 
741       end:
742 	/* disable all links -- to be activated on use */
743 	acpi_evaluate_object(device->handle, "_DIS", NULL, NULL);
744 	mutex_unlock(&acpi_link_lock);
745 
746 	if (result)
747 		kfree(link);
748 
749 	return result;
750 }
751 
752 static int acpi_pci_link_resume(struct acpi_pci_link *link)
753 {
754 	if (link->refcnt && link->irq.active && link->irq.initialized)
755 		return (acpi_pci_link_set(link, link->irq.active));
756 
757 	return 0;
758 }
759 
760 static void irqrouter_resume(void)
761 {
762 	struct acpi_pci_link *link;
763 
764 	list_for_each_entry(link, &acpi_link_list, list) {
765 		acpi_pci_link_resume(link);
766 	}
767 }
768 
769 static int acpi_pci_link_remove(struct acpi_device *device, int type)
770 {
771 	struct acpi_pci_link *link;
772 
773 	link = acpi_driver_data(device);
774 
775 	mutex_lock(&acpi_link_lock);
776 	list_del(&link->list);
777 	mutex_unlock(&acpi_link_lock);
778 
779 	kfree(link);
780 	return 0;
781 }
782 
783 /*
784  * modify acpi_irq_penalty[] from cmdline
785  */
786 static int __init acpi_irq_penalty_update(char *str, int used)
787 {
788 	int i;
789 
790 	for (i = 0; i < 16; i++) {
791 		int retval;
792 		int irq;
793 
794 		retval = get_option(&str, &irq);
795 
796 		if (!retval)
797 			break;	/* no number found */
798 
799 		if (irq < 0)
800 			continue;
801 
802 		if (irq >= ARRAY_SIZE(acpi_irq_penalty))
803 			continue;
804 
805 		if (used)
806 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
807 		else
808 			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
809 
810 		if (retval != 2)	/* no next number */
811 			break;
812 	}
813 	return 1;
814 }
815 
816 /*
817  * We'd like PNP to call this routine for the
818  * single ISA_USED value for each legacy device.
819  * But instead it calls us with each POSSIBLE setting.
820  * There is no ISA_POSSIBLE weight, so we simply use
821  * the (small) PCI_USING penalty.
822  */
823 void acpi_penalize_isa_irq(int irq, int active)
824 {
825 	if (irq >= 0 && irq < ARRAY_SIZE(acpi_irq_penalty)) {
826 		if (active)
827 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
828 		else
829 			acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
830 	}
831 }
832 
833 /*
834  * Over-ride default table to reserve additional IRQs for use by ISA
835  * e.g. acpi_irq_isa=5
836  * Useful for telling ACPI how not to interfere with your ISA sound card.
837  */
838 static int __init acpi_irq_isa(char *str)
839 {
840 	return acpi_irq_penalty_update(str, 1);
841 }
842 
843 __setup("acpi_irq_isa=", acpi_irq_isa);
844 
845 /*
846  * Over-ride default table to free additional IRQs for use by PCI
847  * e.g. acpi_irq_pci=7,15
848  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
849  */
850 static int __init acpi_irq_pci(char *str)
851 {
852 	return acpi_irq_penalty_update(str, 0);
853 }
854 
855 __setup("acpi_irq_pci=", acpi_irq_pci);
856 
857 static int __init acpi_irq_nobalance_set(char *str)
858 {
859 	acpi_irq_balance = 0;
860 	return 1;
861 }
862 
863 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
864 
865 static int __init acpi_irq_balance_set(char *str)
866 {
867 	acpi_irq_balance = 1;
868 	return 1;
869 }
870 
871 __setup("acpi_irq_balance", acpi_irq_balance_set);
872 
873 static struct syscore_ops irqrouter_syscore_ops = {
874 	.resume = irqrouter_resume,
875 };
876 
877 static int __init irqrouter_init_ops(void)
878 {
879 	if (!acpi_disabled && !acpi_noirq)
880 		register_syscore_ops(&irqrouter_syscore_ops);
881 
882 	return 0;
883 }
884 
885 device_initcall(irqrouter_init_ops);
886 
887 static int __init acpi_pci_link_init(void)
888 {
889 	if (acpi_noirq)
890 		return 0;
891 
892 	if (acpi_irq_balance == -1) {
893 		/* no command line switch: enable balancing in IOAPIC mode */
894 		if (acpi_irq_model == ACPI_IRQ_MODEL_IOAPIC)
895 			acpi_irq_balance = 1;
896 		else
897 			acpi_irq_balance = 0;
898 	}
899 
900 	if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
901 		return -ENODEV;
902 
903 	return 0;
904 }
905 
906 subsys_initcall(acpi_pci_link_init);
907