xref: /openbmc/linux/drivers/acpi/pci_irq.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
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 
27 #include <linux/config.h>
28 
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/init.h>
32 #include <linux/types.h>
33 #include <linux/proc_fs.h>
34 #include <linux/spinlock.h>
35 #include <linux/pm.h>
36 #include <linux/pci.h>
37 #include <linux/acpi.h>
38 #include <acpi/acpi_bus.h>
39 #include <acpi/acpi_drivers.h>
40 
41 #define _COMPONENT		ACPI_PCI_COMPONENT
42 ACPI_MODULE_NAME("pci_irq")
43 
44 static struct acpi_prt_list acpi_prt;
45 static DEFINE_SPINLOCK(acpi_prt_lock);
46 
47 /* --------------------------------------------------------------------------
48                          PCI IRQ Routing Table (PRT) Support
49    -------------------------------------------------------------------------- */
50 
51 static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,
52 							  int bus,
53 							  int device, int pin)
54 {
55 	struct list_head *node = NULL;
56 	struct acpi_prt_entry *entry = NULL;
57 
58 	ACPI_FUNCTION_TRACE("acpi_pci_irq_find_prt_entry");
59 
60 	if (!acpi_prt.count)
61 		return_PTR(NULL);
62 
63 	/*
64 	 * Parse through all PRT entries looking for a match on the specified
65 	 * PCI device's segment, bus, device, and pin (don't care about func).
66 	 *
67 	 */
68 	spin_lock(&acpi_prt_lock);
69 	list_for_each(node, &acpi_prt.entries) {
70 		entry = list_entry(node, struct acpi_prt_entry, node);
71 		if ((segment == entry->id.segment)
72 		    && (bus == entry->id.bus)
73 		    && (device == entry->id.device)
74 		    && (pin == entry->pin)) {
75 			spin_unlock(&acpi_prt_lock);
76 			return_PTR(entry);
77 		}
78 	}
79 
80 	spin_unlock(&acpi_prt_lock);
81 	return_PTR(NULL);
82 }
83 
84 static int
85 acpi_pci_irq_add_entry(acpi_handle handle,
86 		       int segment, int bus, struct acpi_pci_routing_table *prt)
87 {
88 	struct acpi_prt_entry *entry = NULL;
89 
90 	ACPI_FUNCTION_TRACE("acpi_pci_irq_add_entry");
91 
92 	if (!prt)
93 		return_VALUE(-EINVAL);
94 
95 	entry = kmalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
96 	if (!entry)
97 		return_VALUE(-ENOMEM);
98 	memset(entry, 0, sizeof(struct acpi_prt_entry));
99 
100 	entry->id.segment = segment;
101 	entry->id.bus = bus;
102 	entry->id.device = (prt->address >> 16) & 0xFFFF;
103 	entry->id.function = prt->address & 0xFFFF;
104 	entry->pin = prt->pin;
105 
106 	/*
107 	 * Type 1: Dynamic
108 	 * ---------------
109 	 * The 'source' field specifies the PCI interrupt link device used to
110 	 * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
111 	 * indicates which resource descriptor in the resource template (of
112 	 * the link device) this interrupt is allocated from.
113 	 *
114 	 * NOTE: Don't query the Link Device for IRQ information at this time
115 	 *       because Link Device enumeration may not have occurred yet
116 	 *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
117 	 *       namespace).
118 	 */
119 	if (prt->source[0]) {
120 		acpi_get_handle(handle, prt->source, &entry->link.handle);
121 		entry->link.index = prt->source_index;
122 	}
123 	/*
124 	 * Type 2: Static
125 	 * --------------
126 	 * The 'source' field is NULL, and the 'source_index' field specifies
127 	 * the IRQ value, which is hardwired to specific interrupt inputs on
128 	 * the interrupt controller.
129 	 */
130 	else
131 		entry->link.index = prt->source_index;
132 
133 	ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
134 			      "      %02X:%02X:%02X[%c] -> %s[%d]\n",
135 			      entry->id.segment, entry->id.bus,
136 			      entry->id.device, ('A' + entry->pin), prt->source,
137 			      entry->link.index));
138 
139 	spin_lock(&acpi_prt_lock);
140 	list_add_tail(&entry->node, &acpi_prt.entries);
141 	acpi_prt.count++;
142 	spin_unlock(&acpi_prt_lock);
143 
144 	return_VALUE(0);
145 }
146 
147 static void
148 acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
149 {
150 	if (segment == entry->id.segment && bus == entry->id.bus) {
151 		acpi_prt.count--;
152 		list_del(&entry->node);
153 		kfree(entry);
154 	}
155 }
156 
157 int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
158 {
159 	acpi_status status = AE_OK;
160 	char *pathname = NULL;
161 	struct acpi_buffer buffer = { 0, NULL };
162 	struct acpi_pci_routing_table *prt = NULL;
163 	struct acpi_pci_routing_table *entry = NULL;
164 	static int first_time = 1;
165 
166 	ACPI_FUNCTION_TRACE("acpi_pci_irq_add_prt");
167 
168 	pathname = (char *)kmalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
169 	if (!pathname)
170 		return_VALUE(-ENOMEM);
171 	memset(pathname, 0, ACPI_PATHNAME_MAX);
172 
173 	if (first_time) {
174 		acpi_prt.count = 0;
175 		INIT_LIST_HEAD(&acpi_prt.entries);
176 		first_time = 0;
177 	}
178 
179 	/*
180 	 * NOTE: We're given a 'handle' to the _PRT object's parent device
181 	 *       (either a PCI root bridge or PCI-PCI bridge).
182 	 */
183 
184 	buffer.length = ACPI_PATHNAME_MAX;
185 	buffer.pointer = pathname;
186 	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
187 
188 	printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
189 	       pathname);
190 
191 	/*
192 	 * Evaluate this _PRT and add its entries to our global list (acpi_prt).
193 	 */
194 
195 	buffer.length = 0;
196 	buffer.pointer = NULL;
197 	kfree(pathname);
198 	status = acpi_get_irq_routing_table(handle, &buffer);
199 	if (status != AE_BUFFER_OVERFLOW) {
200 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRT [%s]\n",
201 				  acpi_format_exception(status)));
202 		return_VALUE(-ENODEV);
203 	}
204 
205 	prt = kmalloc(buffer.length, GFP_KERNEL);
206 	if (!prt) {
207 		return_VALUE(-ENOMEM);
208 	}
209 	memset(prt, 0, buffer.length);
210 	buffer.pointer = prt;
211 
212 	status = acpi_get_irq_routing_table(handle, &buffer);
213 	if (ACPI_FAILURE(status)) {
214 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "Error evaluating _PRT [%s]\n",
215 				  acpi_format_exception(status)));
216 		kfree(buffer.pointer);
217 		return_VALUE(-ENODEV);
218 	}
219 
220 	entry = prt;
221 
222 	while (entry && (entry->length > 0)) {
223 		acpi_pci_irq_add_entry(handle, segment, bus, entry);
224 		entry = (struct acpi_pci_routing_table *)
225 		    ((unsigned long)entry + entry->length);
226 	}
227 
228 	kfree(prt);
229 
230 	return_VALUE(0);
231 }
232 
233 void acpi_pci_irq_del_prt(int segment, int bus)
234 {
235 	struct list_head *node = NULL, *n = NULL;
236 	struct acpi_prt_entry *entry = NULL;
237 
238 	if (!acpi_prt.count) {
239 		return;
240 	}
241 
242 	printk(KERN_DEBUG
243 	       "ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,
244 	       bus);
245 	spin_lock(&acpi_prt_lock);
246 	list_for_each_safe(node, n, &acpi_prt.entries) {
247 		entry = list_entry(node, struct acpi_prt_entry, node);
248 
249 		acpi_pci_irq_del_entry(segment, bus, entry);
250 	}
251 	spin_unlock(&acpi_prt_lock);
252 }
253 
254 /* --------------------------------------------------------------------------
255                           PCI Interrupt Routing Support
256    -------------------------------------------------------------------------- */
257 typedef int (*irq_lookup_func) (struct acpi_prt_entry *, int *, int *, char **);
258 
259 static int
260 acpi_pci_allocate_irq(struct acpi_prt_entry *entry,
261 		      int *edge_level, int *active_high_low, char **link)
262 {
263 	int irq;
264 
265 	ACPI_FUNCTION_TRACE("acpi_pci_allocate_irq");
266 
267 	if (entry->link.handle) {
268 		irq = acpi_pci_link_allocate_irq(entry->link.handle,
269 						 entry->link.index, edge_level,
270 						 active_high_low, link);
271 		if (irq < 0) {
272 			ACPI_DEBUG_PRINT((ACPI_DB_WARN,
273 					  "Invalid IRQ link routing entry\n"));
274 			return_VALUE(-1);
275 		}
276 	} else {
277 		irq = entry->link.index;
278 		*edge_level = ACPI_LEVEL_SENSITIVE;
279 		*active_high_low = ACPI_ACTIVE_LOW;
280 	}
281 
282 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));
283 	return_VALUE(irq);
284 }
285 
286 static int
287 acpi_pci_free_irq(struct acpi_prt_entry *entry,
288 		  int *edge_level, int *active_high_low, char **link)
289 {
290 	int irq;
291 
292 	ACPI_FUNCTION_TRACE("acpi_pci_free_irq");
293 	if (entry->link.handle) {
294 		irq = acpi_pci_link_free_irq(entry->link.handle);
295 	} else {
296 		irq = entry->link.index;
297 	}
298 	return_VALUE(irq);
299 }
300 
301 /*
302  * acpi_pci_irq_lookup
303  * success: return IRQ >= 0
304  * failure: return -1
305  */
306 static int
307 acpi_pci_irq_lookup(struct pci_bus *bus,
308 		    int device,
309 		    int pin,
310 		    int *edge_level,
311 		    int *active_high_low, char **link, irq_lookup_func func)
312 {
313 	struct acpi_prt_entry *entry = NULL;
314 	int segment = pci_domain_nr(bus);
315 	int bus_nr = bus->number;
316 	int ret;
317 
318 	ACPI_FUNCTION_TRACE("acpi_pci_irq_lookup");
319 
320 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
321 			  "Searching for PRT entry for %02x:%02x:%02x[%c]\n",
322 			  segment, bus_nr, device, ('A' + pin)));
323 
324 	entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);
325 	if (!entry) {
326 		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));
327 		return_VALUE(-1);
328 	}
329 
330 	ret = func(entry, edge_level, active_high_low, link);
331 	return_VALUE(ret);
332 }
333 
334 /*
335  * acpi_pci_irq_derive
336  * success: return IRQ >= 0
337  * failure: return < 0
338  */
339 static int
340 acpi_pci_irq_derive(struct pci_dev *dev,
341 		    int pin,
342 		    int *edge_level,
343 		    int *active_high_low, char **link, irq_lookup_func func)
344 {
345 	struct pci_dev *bridge = dev;
346 	int irq = -1;
347 	u8 bridge_pin = 0;
348 
349 	ACPI_FUNCTION_TRACE("acpi_pci_irq_derive");
350 
351 	if (!dev)
352 		return_VALUE(-EINVAL);
353 
354 	/*
355 	 * Attempt to derive an IRQ for this device from a parent bridge's
356 	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
357 	 */
358 	while (irq < 0 && bridge->bus->self) {
359 		pin = (pin + PCI_SLOT(bridge->devfn)) % 4;
360 		bridge = bridge->bus->self;
361 
362 		if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
363 			/* PC card has the same IRQ as its cardbridge */
364 			pci_read_config_byte(bridge, PCI_INTERRUPT_PIN,
365 					     &bridge_pin);
366 			if (!bridge_pin) {
367 				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
368 						  "No interrupt pin configured for device %s\n",
369 						  pci_name(bridge)));
370 				return_VALUE(-1);
371 			}
372 			/* Pin is from 0 to 3 */
373 			bridge_pin--;
374 			pin = bridge_pin;
375 		}
376 
377 		irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),
378 					  pin, edge_level, active_high_low,
379 					  link, func);
380 	}
381 
382 	if (irq < 0) {
383 		ACPI_DEBUG_PRINT((ACPI_DB_WARN,
384 				  "Unable to derive IRQ for device %s\n",
385 				  pci_name(dev)));
386 		return_VALUE(-1);
387 	}
388 
389 	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",
390 			  irq, pci_name(dev), pci_name(bridge)));
391 
392 	return_VALUE(irq);
393 }
394 
395 /*
396  * acpi_pci_irq_enable
397  * success: return 0
398  * failure: return < 0
399  */
400 
401 int acpi_pci_irq_enable(struct pci_dev *dev)
402 {
403 	int irq = 0;
404 	u8 pin = 0;
405 	int edge_level = ACPI_LEVEL_SENSITIVE;
406 	int active_high_low = ACPI_ACTIVE_LOW;
407 	char *link = NULL;
408 	int rc;
409 
410 	ACPI_FUNCTION_TRACE("acpi_pci_irq_enable");
411 
412 	if (!dev)
413 		return_VALUE(-EINVAL);
414 
415 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
416 	if (!pin) {
417 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
418 				  "No interrupt pin configured for device %s\n",
419 				  pci_name(dev)));
420 		return_VALUE(0);
421 	}
422 	pin--;
423 
424 	if (!dev->bus) {
425 		ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
426 				  "Invalid (NULL) 'bus' field\n"));
427 		return_VALUE(-ENODEV);
428 	}
429 
430 	/*
431 	 * First we check the PCI IRQ routing table (PRT) for an IRQ.  PRT
432 	 * values override any BIOS-assigned IRQs set during boot.
433 	 */
434 	irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
435 				  &edge_level, &active_high_low, &link,
436 				  acpi_pci_allocate_irq);
437 
438 	/*
439 	 * If no PRT entry was found, we'll try to derive an IRQ from the
440 	 * device's parent bridge.
441 	 */
442 	if (irq < 0)
443 		irq = acpi_pci_irq_derive(dev, pin, &edge_level,
444 					  &active_high_low, &link,
445 					  acpi_pci_allocate_irq);
446 
447 	/*
448 	 * No IRQ known to the ACPI subsystem - maybe the BIOS /
449 	 * driver reported one, then use it. Exit in any case.
450 	 */
451 	if (irq < 0) {
452 		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",
453 		       pci_name(dev), ('A' + pin));
454 		/* Interrupt Line values above 0xF are forbidden */
455 		if (dev->irq > 0 && (dev->irq <= 0xF)) {
456 			printk(" - using IRQ %d\n", dev->irq);
457 			acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,
458 					  ACPI_ACTIVE_LOW);
459 			return_VALUE(0);
460 		} else {
461 			printk("\n");
462 			return_VALUE(0);
463 		}
464 	}
465 
466 	rc = acpi_register_gsi(irq, edge_level, active_high_low);
467 	if (rc < 0) {
468 		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "
469 		       "to register GSI\n", pci_name(dev), ('A' + pin));
470 		return_VALUE(rc);
471 	}
472 	dev->irq = rc;
473 
474 	printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",
475 	       pci_name(dev), 'A' + pin);
476 
477 	if (link)
478 		printk("Link [%s] -> ", link);
479 
480 	printk("GSI %u (%s, %s) -> IRQ %d\n", irq,
481 	       (edge_level == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
482 	       (active_high_low == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);
483 
484 	return_VALUE(0);
485 }
486 
487 EXPORT_SYMBOL(acpi_pci_irq_enable);
488 
489 /* FIXME: implement x86/x86_64 version */
490 void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)
491 {
492 }
493 
494 void acpi_pci_irq_disable(struct pci_dev *dev)
495 {
496 	int gsi = 0;
497 	u8 pin = 0;
498 	int edge_level = ACPI_LEVEL_SENSITIVE;
499 	int active_high_low = ACPI_ACTIVE_LOW;
500 
501 	ACPI_FUNCTION_TRACE("acpi_pci_irq_disable");
502 
503 	if (!dev || !dev->bus)
504 		return_VOID;
505 
506 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
507 	if (!pin)
508 		return_VOID;
509 	pin--;
510 
511 	/*
512 	 * First we check the PCI IRQ routing table (PRT) for an IRQ.
513 	 */
514 	gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
515 				  &edge_level, &active_high_low, NULL,
516 				  acpi_pci_free_irq);
517 	/*
518 	 * If no PRT entry was found, we'll try to derive an IRQ from the
519 	 * device's parent bridge.
520 	 */
521 	if (gsi < 0)
522 		gsi = acpi_pci_irq_derive(dev, pin,
523 					  &edge_level, &active_high_low, NULL,
524 					  acpi_pci_free_irq);
525 	if (gsi < 0)
526 		return_VOID;
527 
528 	/*
529 	 * TBD: It might be worth clearing dev->irq by magic constant
530 	 * (e.g. PCI_UNDEFINED_IRQ).
531 	 */
532 
533 	printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",
534 	       pci_name(dev));
535 
536 	acpi_unregister_gsi(gsi);
537 
538 	return_VOID;
539 }
540