xref: /openbmc/linux/drivers/acpi/pci_link.c (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
1 /*
2  *  pci_link.c - ACPI PCI Interrupt Link Device Driver ($Revision: 34 $)
3  *
4  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
5  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
6  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
7  *
8  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9  *
10  *  This program is free software; you can redistribute it and/or modify
11  *  it under the terms of the GNU General Public License as published by
12  *  the Free Software Foundation; either version 2 of the License, or (at
13  *  your option) any later version.
14  *
15  *  This program is distributed in the hope that it will be useful, but
16  *  WITHOUT ANY WARRANTY; without even the implied warranty of
17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  *  General Public License for more details.
19  *
20  *  You should have received a copy of the GNU General Public License along
21  *  with this program; if not, write to the Free Software Foundation, Inc.,
22  *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
23  *
24  * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
25  *
26  * TBD:
27  *      1. Support more than one IRQ resource entry per link device (index).
28  *	2. Implement start/stop mechanism and use ACPI Bus Driver facilities
29  *	   for IRQ management (e.g. start()->_SRS).
30  */
31 
32 #include <linux/sysdev.h>
33 #include <linux/kernel.h>
34 #include <linux/module.h>
35 #include <linux/init.h>
36 #include <linux/types.h>
37 #include <linux/proc_fs.h>
38 #include <linux/spinlock.h>
39 #include <linux/pm.h>
40 #include <linux/pci.h>
41 
42 #include <acpi/acpi_bus.h>
43 #include <acpi/acpi_drivers.h>
44 
45 
46 #define _COMPONENT		ACPI_PCI_COMPONENT
47 ACPI_MODULE_NAME		("pci_link")
48 
49 #define ACPI_PCI_LINK_CLASS		"pci_irq_routing"
50 #define ACPI_PCI_LINK_HID		"PNP0C0F"
51 #define ACPI_PCI_LINK_DRIVER_NAME	"ACPI PCI Interrupt Link Driver"
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 
56 #define ACPI_PCI_LINK_MAX_POSSIBLE 16
57 
58 static int acpi_pci_link_add (struct acpi_device *device);
59 static int acpi_pci_link_remove (struct acpi_device *device, int type);
60 
61 static struct acpi_driver acpi_pci_link_driver = {
62 	.name =		ACPI_PCI_LINK_DRIVER_NAME,
63 	.class =	ACPI_PCI_LINK_CLASS,
64 	.ids =		ACPI_PCI_LINK_HID,
65 	.ops =		{
66 				.add =    acpi_pci_link_add,
67 				.remove = acpi_pci_link_remove,
68 			},
69 };
70 
71 struct acpi_pci_link_irq {
72 	u8			active;			/* Current IRQ */
73 	u8			edge_level;		/* All IRQs */
74 	u8			active_high_low;	/* All IRQs */
75 	u8			initialized;
76 	u8			resource_type;
77 	u8			possible_count;
78 	u8			possible[ACPI_PCI_LINK_MAX_POSSIBLE];
79 };
80 
81 struct acpi_pci_link {
82 	struct list_head	node;
83 	struct acpi_device	*device;
84 	acpi_handle		handle;
85 	struct acpi_pci_link_irq irq;
86 };
87 
88 static struct {
89 	int			count;
90 	struct list_head	entries;
91 }				acpi_link;
92 
93 
94 /* --------------------------------------------------------------------------
95                             PCI Link Device Management
96    -------------------------------------------------------------------------- */
97 
98 /*
99  * set context (link) possible list from resource list
100  */
101 static acpi_status
102 acpi_pci_link_check_possible (
103 	struct acpi_resource	*resource,
104 	void			*context)
105 {
106 	struct acpi_pci_link	*link = (struct acpi_pci_link *) context;
107 	u32			i = 0;
108 
109 	ACPI_FUNCTION_TRACE("acpi_pci_link_check_possible");
110 
111 	switch (resource->id) {
112 	case ACPI_RSTYPE_START_DPF:
113 		return_ACPI_STATUS(AE_OK);
114 	case ACPI_RSTYPE_IRQ:
115 	{
116 		struct acpi_resource_irq *p = &resource->data.irq;
117 		if (!p || !p->number_of_interrupts) {
118 			ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Blank IRQ resource\n"));
119 			return_ACPI_STATUS(AE_OK);
120 		}
121 		for (i = 0; (i<p->number_of_interrupts && i<ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
122 			if (!p->interrupts[i]) {
123 				ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Invalid IRQ %d\n", p->interrupts[i]));
124 				continue;
125 			}
126 			link->irq.possible[i] = p->interrupts[i];
127 			link->irq.possible_count++;
128 		}
129 		link->irq.edge_level = p->edge_level;
130 		link->irq.active_high_low = p->active_high_low;
131 		link->irq.resource_type = ACPI_RSTYPE_IRQ;
132 		break;
133 	}
134 	case ACPI_RSTYPE_EXT_IRQ:
135 	{
136 		struct acpi_resource_ext_irq *p = &resource->data.extended_irq;
137 		if (!p || !p->number_of_interrupts) {
138 			ACPI_DEBUG_PRINT((ACPI_DB_WARN,
139 				"Blank EXT IRQ resource\n"));
140 			return_ACPI_STATUS(AE_OK);
141 		}
142 		for (i = 0; (i<p->number_of_interrupts && i<ACPI_PCI_LINK_MAX_POSSIBLE); i++) {
143 			if (!p->interrupts[i]) {
144 				ACPI_DEBUG_PRINT((ACPI_DB_WARN, "Invalid IRQ %d\n", p->interrupts[i]));
145 				continue;
146 			}
147 			link->irq.possible[i] = p->interrupts[i];
148 			link->irq.possible_count++;
149 		}
150 		link->irq.edge_level = p->edge_level;
151 		link->irq.active_high_low = p->active_high_low;
152 		link->irq.resource_type = ACPI_RSTYPE_EXT_IRQ;
153 		break;
154 	}
155 	default:
156 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
157 			"Resource is not an IRQ entry\n"));
158 		return_ACPI_STATUS(AE_OK);
159 	}
160 
161 	return_ACPI_STATUS(AE_CTRL_TERMINATE);
162 }
163 
164 
165 static int
166 acpi_pci_link_get_possible (
167 	struct acpi_pci_link	*link)
168 {
169 	acpi_status		status;
170 
171 	ACPI_FUNCTION_TRACE("acpi_pci_link_get_possible");
172 
173 	if (!link)
174 		return_VALUE(-EINVAL);
175 
176 	status = acpi_walk_resources(link->handle, METHOD_NAME__PRS,
177 			acpi_pci_link_check_possible, link);
178 	if (ACPI_FAILURE(status)) {
179 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRS\n"));
180 		return_VALUE(-ENODEV);
181 	}
182 
183 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
184 		"Found %d possible IRQs\n", link->irq.possible_count));
185 
186 	return_VALUE(0);
187 }
188 
189 
190 static acpi_status
191 acpi_pci_link_check_current (
192 	struct acpi_resource	*resource,
193 	void			*context)
194 {
195 	int			*irq = (int *) context;
196 
197 	ACPI_FUNCTION_TRACE("acpi_pci_link_check_current");
198 
199 	switch (resource->id) {
200 	case ACPI_RSTYPE_IRQ:
201 	{
202 		struct acpi_resource_irq *p = &resource->data.irq;
203 		if (!p || !p->number_of_interrupts) {
204 			/*
205 			 * IRQ descriptors may have no IRQ# bits set,
206 			 * particularly those those w/ _STA disabled
207 			 */
208 			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
209 				"Blank IRQ resource\n"));
210 			return_ACPI_STATUS(AE_OK);
211 		}
212 		*irq = p->interrupts[0];
213 		break;
214 	}
215 	case ACPI_RSTYPE_EXT_IRQ:
216 	{
217 		struct acpi_resource_ext_irq *p = &resource->data.extended_irq;
218 		if (!p || !p->number_of_interrupts) {
219 			/*
220 			 * extended IRQ descriptors must
221 			 * return at least 1 IRQ
222 			 */
223 			ACPI_DEBUG_PRINT((ACPI_DB_WARN,
224 				"Blank EXT IRQ resource\n"));
225 			return_ACPI_STATUS(AE_OK);
226 		}
227 		*irq = p->interrupts[0];
228 		break;
229 	}
230 	default:
231 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
232 			"Resource isn't an IRQ\n"));
233 		return_ACPI_STATUS(AE_OK);
234 	}
235 	return_ACPI_STATUS(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
246 acpi_pci_link_get_current (
247 	struct acpi_pci_link	*link)
248 {
249 	int			result = 0;
250 	acpi_status		status = AE_OK;
251 	int			irq = 0;
252 
253 	ACPI_FUNCTION_TRACE("acpi_pci_link_get_current");
254 
255 	if (!link || !link->handle)
256 		return_VALUE(-EINVAL);
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 			ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "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_VALUE(0);
272 		}
273 	}
274 
275 	/*
276 	 * Query and parse _CRS to get the current IRQ assignment.
277 	 */
278 
279 	status = acpi_walk_resources(link->handle, METHOD_NAME__CRS,
280 			acpi_pci_link_check_current, &irq);
281 	if (ACPI_FAILURE(status)) {
282 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _CRS\n"));
283 		result = -ENODEV;
284 		goto end;
285 	}
286 
287 	if (acpi_strict && !irq) {
288 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "_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_VALUE(result);
298 }
299 
300 static int
301 acpi_pci_link_set (
302 	struct acpi_pci_link	*link,
303 	int			irq)
304 {
305 	int			result = 0;
306 	acpi_status		status = AE_OK;
307 	struct {
308 		struct acpi_resource	res;
309 		struct acpi_resource	end;
310 	}    *resource;
311 	struct acpi_buffer	buffer = {0, NULL};
312 
313 	ACPI_FUNCTION_TRACE("acpi_pci_link_set");
314 
315 	if (!link || !irq)
316 		return_VALUE(-EINVAL);
317 
318 	resource = kmalloc( sizeof(*resource)+1, GFP_KERNEL);
319 	if(!resource)
320 		return_VALUE(-ENOMEM);
321 
322 	memset(resource, 0, sizeof(*resource)+1);
323 	buffer.length = sizeof(*resource) +1;
324 	buffer.pointer = resource;
325 
326 	switch(link->irq.resource_type) {
327 	case ACPI_RSTYPE_IRQ:
328 		resource->res.id = ACPI_RSTYPE_IRQ;
329 		resource->res.length = sizeof(struct acpi_resource);
330 		resource->res.data.irq.edge_level = link->irq.edge_level;
331 		resource->res.data.irq.active_high_low = link->irq.active_high_low;
332 		if (link->irq.edge_level == ACPI_EDGE_SENSITIVE)
333 			resource->res.data.irq.shared_exclusive = ACPI_EXCLUSIVE;
334 		else
335 			resource->res.data.irq.shared_exclusive = ACPI_SHARED;
336 		resource->res.data.irq.number_of_interrupts = 1;
337 		resource->res.data.irq.interrupts[0] = irq;
338 		break;
339 
340 	case ACPI_RSTYPE_EXT_IRQ:
341 		resource->res.id = ACPI_RSTYPE_EXT_IRQ;
342 		resource->res.length = sizeof(struct acpi_resource);
343 		resource->res.data.extended_irq.producer_consumer = ACPI_CONSUMER;
344 		resource->res.data.extended_irq.edge_level = link->irq.edge_level;
345 		resource->res.data.extended_irq.active_high_low = link->irq.active_high_low;
346 		if (link->irq.edge_level == ACPI_EDGE_SENSITIVE)
347 			resource->res.data.irq.shared_exclusive = ACPI_EXCLUSIVE;
348 		else
349 			resource->res.data.irq.shared_exclusive = ACPI_SHARED;
350 		resource->res.data.extended_irq.number_of_interrupts = 1;
351 		resource->res.data.extended_irq.interrupts[0] = irq;
352 		/* ignore resource_source, it's optional */
353 		break;
354 	default:
355 		printk("ACPI BUG: resource_type %d\n", link->irq.resource_type);
356 		result = -EINVAL;
357 		goto end;
358 
359 	}
360 	resource->end.id = ACPI_RSTYPE_END_TAG;
361 
362 	/* Attempt to set the resource */
363 	status = acpi_set_current_resources(link->handle, &buffer);
364 
365 	/* check for total failure */
366 	if (ACPI_FAILURE(status)) {
367 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _SRS\n"));
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 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "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),
404 			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_VALUE(result);
413 }
414 
415 
416 /* --------------------------------------------------------------------------
417                             PCI Link IRQ Management
418    -------------------------------------------------------------------------- */
419 
420 /*
421  * "acpi_irq_balance" (default in APIC mode) enables ACPI to use PIC Interrupt
422  * Link Devices to move the PIRQs around to minimize sharing.
423  *
424  * "acpi_irq_nobalance" (default in PIC mode) tells ACPI not to move any PIC IRQs
425  * that the BIOS has already set to active.  This is necessary because
426  * ACPI has no automatic means of knowing what ISA IRQs are used.  Note that
427  * if the BIOS doesn't set a Link Device active, ACPI needs to program it
428  * even if acpi_irq_nobalance is set.
429  *
430  * A tables of penalties avoids directing PCI interrupts to well known
431  * ISA IRQs. Boot params are available to over-ride the default table:
432  *
433  * List interrupts that are free for PCI use.
434  * acpi_irq_pci=n[,m]
435  *
436  * List interrupts that should not be used for PCI:
437  * acpi_irq_isa=n[,m]
438  *
439  * Note that PCI IRQ routers have a list of possible IRQs,
440  * which may not include the IRQs this table says are available.
441  *
442  * Since this heuristic can't tell the difference between a link
443  * that no device will attach to, vs. a link which may be shared
444  * by multiple active devices -- it is not optimal.
445  *
446  * If interrupt performance is that important, get an IO-APIC system
447  * with a pin dedicated to each device.  Or for that matter, an MSI
448  * enabled system.
449  */
450 
451 #define ACPI_MAX_IRQS		256
452 #define ACPI_MAX_ISA_IRQ	16
453 
454 #define PIRQ_PENALTY_PCI_AVAILABLE	(0)
455 #define PIRQ_PENALTY_PCI_POSSIBLE	(16*16)
456 #define PIRQ_PENALTY_PCI_USING		(16*16*16)
457 #define PIRQ_PENALTY_ISA_TYPICAL	(16*16*16*16)
458 #define PIRQ_PENALTY_ISA_USED		(16*16*16*16*16)
459 #define PIRQ_PENALTY_ISA_ALWAYS		(16*16*16*16*16*16)
460 
461 static int acpi_irq_penalty[ACPI_MAX_IRQS] = {
462 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ0 timer */
463 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ1 keyboard */
464 	PIRQ_PENALTY_ISA_ALWAYS,	/* IRQ2 cascade */
465 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ3	serial */
466 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ4	serial */
467 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ5 sometimes SoundBlaster */
468 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ6 */
469 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ7 parallel, spurious */
470 	PIRQ_PENALTY_ISA_TYPICAL,	/* IRQ8 rtc, sometimes */
471 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ9  PCI, often acpi */
472 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ10 PCI */
473 	PIRQ_PENALTY_PCI_AVAILABLE,	/* IRQ11 PCI */
474 	PIRQ_PENALTY_ISA_USED,	/* IRQ12 mouse */
475 	PIRQ_PENALTY_ISA_USED,	/* IRQ13 fpe, sometimes */
476 	PIRQ_PENALTY_ISA_USED,	/* IRQ14 ide0 */
477 	PIRQ_PENALTY_ISA_USED,	/* IRQ15 ide1 */
478 			/* >IRQ15 */
479 };
480 
481 int __init
482 acpi_irq_penalty_init(void)
483 {
484 	struct list_head	*node = NULL;
485 	struct acpi_pci_link    *link = NULL;
486 	int			i = 0;
487 
488 	ACPI_FUNCTION_TRACE("acpi_irq_penalty_init");
489 
490 	/*
491 	 * Update penalties to facilitate IRQ balancing.
492 	 */
493 	list_for_each(node, &acpi_link.entries) {
494 
495 		link = list_entry(node, struct acpi_pci_link, node);
496 		if (!link) {
497 			ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
498 			continue;
499 		}
500 
501 		/*
502 		 * reflect the possible and active irqs in the penalty table --
503 		 * useful for breaking ties.
504 		 */
505 		if (link->irq.possible_count) {
506 			int penalty = PIRQ_PENALTY_PCI_POSSIBLE / link->irq.possible_count;
507 
508 			for (i = 0; i < link->irq.possible_count; i++) {
509 				if (link->irq.possible[i] < ACPI_MAX_ISA_IRQ)
510 					acpi_irq_penalty[link->irq.possible[i]] += penalty;
511 			}
512 
513 		} else if (link->irq.active) {
514 			acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_POSSIBLE;
515 		}
516 	}
517 	/* Add a penalty for the SCI */
518 	acpi_irq_penalty[acpi_fadt.sci_int] += PIRQ_PENALTY_PCI_USING;
519 
520 	return_VALUE(0);
521 }
522 
523 static int acpi_irq_balance;	/* 0: static, 1: balance */
524 
525 static int acpi_pci_link_allocate(
526 	struct acpi_pci_link	*link)
527 {
528 	int			irq;
529 	int			i;
530 
531 	ACPI_FUNCTION_TRACE("acpi_pci_link_allocate");
532 
533 	if (link->irq.initialized)
534 		return_VALUE(0);
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] > acpi_irq_penalty[link->irq.possible[i]])
569 				irq = link->irq.possible[i];
570 		}
571 	}
572 
573 	/* Attempt to enable the link device at this IRQ. */
574 	if (acpi_pci_link_set(link, irq)) {
575 		printk(PREFIX "Unable to set IRQ for %s [%s] (likely buggy ACPI BIOS).\n"
576 				"Try pci=noacpi or acpi=off\n",
577 			acpi_device_name(link->device),
578 			acpi_device_bid(link->device));
579 		return_VALUE(-ENODEV);
580 	} else {
581 		acpi_irq_penalty[link->irq.active] += PIRQ_PENALTY_PCI_USING;
582 		printk(PREFIX "%s [%s] enabled at IRQ %d\n",
583 			acpi_device_name(link->device),
584 			acpi_device_bid(link->device), link->irq.active);
585 	}
586 
587 	link->irq.initialized = 1;
588 
589 	return_VALUE(0);
590 }
591 
592 /*
593  * acpi_pci_link_get_irq
594  * success: return IRQ >= 0
595  * failure: return -1
596  */
597 
598 int
599 acpi_pci_link_get_irq (
600 	acpi_handle		handle,
601 	int			index,
602 	int			*edge_level,
603 	int			*active_high_low,
604 	char			**name)
605 {
606 	int                     result = 0;
607 	struct acpi_device	*device = NULL;
608 	struct acpi_pci_link	*link = NULL;
609 
610 	ACPI_FUNCTION_TRACE("acpi_pci_link_get_irq");
611 
612 	result = acpi_bus_get_device(handle, &device);
613 	if (result) {
614 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link device\n"));
615 		return_VALUE(-1);
616 	}
617 
618 	link = (struct acpi_pci_link *) acpi_driver_data(device);
619 	if (!link) {
620 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
621 		return_VALUE(-1);
622 	}
623 
624 	/* TBD: Support multiple index (IRQ) entries per Link Device */
625 	if (index) {
626 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid index %d\n", index));
627 		return_VALUE(-1);
628 	}
629 
630 	if (acpi_pci_link_allocate(link))
631 		return_VALUE(-1);
632 
633 	if (!link->irq.active) {
634 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Link active IRQ is 0!\n"));
635 		return_VALUE(-1);
636 	}
637 
638 	if (edge_level) *edge_level = link->irq.edge_level;
639 	if (active_high_low) *active_high_low = link->irq.active_high_low;
640 	if (name) *name = acpi_device_bid(link->device);
641 	return_VALUE(link->irq.active);
642 }
643 
644 
645 /* --------------------------------------------------------------------------
646                                  Driver Interface
647    -------------------------------------------------------------------------- */
648 
649 static int
650 acpi_pci_link_add (
651 	struct acpi_device *device)
652 {
653 	int			result = 0;
654 	struct acpi_pci_link	*link = NULL;
655 	int			i = 0;
656 	int			found = 0;
657 
658 	ACPI_FUNCTION_TRACE("acpi_pci_link_add");
659 
660 	if (!device)
661 		return_VALUE(-EINVAL);
662 
663 	link = kmalloc(sizeof(struct acpi_pci_link), GFP_KERNEL);
664 	if (!link)
665 		return_VALUE(-ENOMEM);
666 	memset(link, 0, sizeof(struct acpi_pci_link));
667 
668 	link->device = device;
669 	link->handle = device->handle;
670 	strcpy(acpi_device_name(device), ACPI_PCI_LINK_DEVICE_NAME);
671 	strcpy(acpi_device_class(device), ACPI_PCI_LINK_CLASS);
672 	acpi_driver_data(device) = link;
673 
674 	result = acpi_pci_link_get_possible(link);
675 	if (result)
676 		goto end;
677 
678 	/* query and set link->irq.active */
679 	acpi_pci_link_get_current(link);
680 
681 	printk(PREFIX "%s [%s] (IRQs", acpi_device_name(device),
682 		acpi_device_bid(device));
683 	for (i = 0; i < link->irq.possible_count; i++) {
684 		if (link->irq.active == link->irq.possible[i]) {
685 			printk(" *%d", link->irq.possible[i]);
686 			found = 1;
687 		}
688 		else
689 			printk(" %d", link->irq.possible[i]);
690 	}
691 
692 	printk(")");
693 
694 	if (!found)
695 		printk(" *%d", link->irq.active);
696 
697 	if(!link->device->status.enabled)
698 		printk(", disabled.");
699 
700 	printk("\n");
701 
702 	/* TBD: Acquire/release lock */
703 	list_add_tail(&link->node, &acpi_link.entries);
704 	acpi_link.count++;
705 
706 end:
707 	/* disable all links -- to be activated on use */
708 	acpi_ut_evaluate_object(link->handle, "_DIS", 0, NULL);
709 
710 	if (result)
711 		kfree(link);
712 
713 	return_VALUE(result);
714 }
715 
716 
717 static int
718 acpi_pci_link_resume (
719 	struct acpi_pci_link	*link)
720 {
721 	ACPI_FUNCTION_TRACE("acpi_pci_link_resume");
722 
723 	if (link->irq.active && link->irq.initialized)
724 		return_VALUE(acpi_pci_link_set(link, link->irq.active));
725 	else
726 		return_VALUE(0);
727 }
728 
729 
730 static int
731 irqrouter_resume(
732 	struct sys_device *dev)
733 {
734 	struct list_head        *node = NULL;
735 	struct acpi_pci_link    *link = NULL;
736 
737 	ACPI_FUNCTION_TRACE("irqrouter_resume");
738 
739 	list_for_each(node, &acpi_link.entries) {
740 
741 		link = list_entry(node, struct acpi_pci_link, node);
742 		if (!link) {
743 			ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Invalid link context\n"));
744 			continue;
745 		}
746 
747 		acpi_pci_link_resume(link);
748 	}
749 	return_VALUE(0);
750 }
751 
752 
753 static int
754 acpi_pci_link_remove (
755 	struct acpi_device	*device,
756 	int			type)
757 {
758 	struct acpi_pci_link *link = NULL;
759 
760 	ACPI_FUNCTION_TRACE("acpi_pci_link_remove");
761 
762 	if (!device || !acpi_driver_data(device))
763 		return_VALUE(-EINVAL);
764 
765 	link = (struct acpi_pci_link *) acpi_driver_data(device);
766 
767 	/* TBD: Acquire/release lock */
768 	list_del(&link->node);
769 
770 	kfree(link);
771 
772 	return_VALUE(0);
773 }
774 
775 /*
776  * modify acpi_irq_penalty[] from cmdline
777  */
778 static int __init acpi_irq_penalty_update(char *str, int used)
779 {
780 	int i;
781 
782 	for (i = 0; i < 16; i++) {
783 		int retval;
784 		int irq;
785 
786 		retval = get_option(&str,&irq);
787 
788 		if (!retval)
789 			break;	/* no number found */
790 
791 		if (irq < 0)
792 			continue;
793 
794 		if (irq >= ACPI_MAX_IRQS)
795 			continue;
796 
797 		if (used)
798 			acpi_irq_penalty[irq] += PIRQ_PENALTY_ISA_USED;
799 		else
800 			acpi_irq_penalty[irq] = PIRQ_PENALTY_PCI_AVAILABLE;
801 
802 		if (retval != 2)	/* no next number */
803 			break;
804 	}
805 	return 1;
806 }
807 
808 /*
809  * We'd like PNP to call this routine for the
810  * single ISA_USED value for each legacy device.
811  * But instead it calls us with each POSSIBLE setting.
812  * There is no ISA_POSSIBLE weight, so we simply use
813  * the (small) PCI_USING penalty.
814  */
815 void acpi_penalize_isa_irq(int irq)
816 {
817 	acpi_irq_penalty[irq] += PIRQ_PENALTY_PCI_USING;
818 }
819 
820 /*
821  * Over-ride default table to reserve additional IRQs for use by ISA
822  * e.g. acpi_irq_isa=5
823  * Useful for telling ACPI how not to interfere with your ISA sound card.
824  */
825 static int __init acpi_irq_isa(char *str)
826 {
827 	return acpi_irq_penalty_update(str, 1);
828 }
829 __setup("acpi_irq_isa=", acpi_irq_isa);
830 
831 /*
832  * Over-ride default table to free additional IRQs for use by PCI
833  * e.g. acpi_irq_pci=7,15
834  * Used for acpi_irq_balance to free up IRQs to reduce PCI IRQ sharing.
835  */
836 static int __init acpi_irq_pci(char *str)
837 {
838 	return acpi_irq_penalty_update(str, 0);
839 }
840 __setup("acpi_irq_pci=", acpi_irq_pci);
841 
842 static int __init acpi_irq_nobalance_set(char *str)
843 {
844 	acpi_irq_balance = 0;
845 	return 1;
846 }
847 __setup("acpi_irq_nobalance", acpi_irq_nobalance_set);
848 
849 int __init acpi_irq_balance_set(char *str)
850 {
851 	acpi_irq_balance = 1;
852 	return 1;
853 }
854 __setup("acpi_irq_balance", acpi_irq_balance_set);
855 
856 
857 static struct sysdev_class irqrouter_sysdev_class = {
858         set_kset_name("irqrouter"),
859         .resume = irqrouter_resume,
860 };
861 
862 
863 static struct sys_device device_irqrouter = {
864 	.id     = 0,
865 	.cls    = &irqrouter_sysdev_class,
866 };
867 
868 
869 static int __init irqrouter_init_sysfs(void)
870 {
871 	int error;
872 
873 	ACPI_FUNCTION_TRACE("irqrouter_init_sysfs");
874 
875 	if (acpi_disabled || acpi_noirq)
876 		return_VALUE(0);
877 
878 	error = sysdev_class_register(&irqrouter_sysdev_class);
879 	if (!error)
880 		error = sysdev_register(&device_irqrouter);
881 
882 	return_VALUE(error);
883 }
884 
885 device_initcall(irqrouter_init_sysfs);
886 
887 
888 static int __init acpi_pci_link_init (void)
889 {
890 	ACPI_FUNCTION_TRACE("acpi_pci_link_init");
891 
892 	if (acpi_noirq)
893 		return_VALUE(0);
894 
895 	acpi_link.count = 0;
896 	INIT_LIST_HEAD(&acpi_link.entries);
897 
898 	if (acpi_bus_register_driver(&acpi_pci_link_driver) < 0)
899 		return_VALUE(-ENODEV);
900 
901 	return_VALUE(0);
902 }
903 
904 subsys_initcall(acpi_pci_link_init);
905