1/*
2 *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 1.1.1.1 $)
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
28#include <linux/kernel.h>
29#include <linux/module.h>
30#include <linux/init.h>
31#include <linux/types.h>
32#include <linux/proc_fs.h>
33#include <linux/spinlock.h>
34#include <linux/pm.h>
35#include <linux/pci.h>
36#include <linux/acpi.h>
37#include <acpi/acpi_bus.h>
38#include <acpi/acpi_drivers.h>
39
40#define _COMPONENT		ACPI_PCI_COMPONENT
41ACPI_MODULE_NAME("pci_irq");
42
43static struct acpi_prt_list acpi_prt;
44static DEFINE_SPINLOCK(acpi_prt_lock);
45
46/* --------------------------------------------------------------------------
47                         PCI IRQ Routing Table (PRT) Support
48   -------------------------------------------------------------------------- */
49
50static struct acpi_prt_entry *acpi_pci_irq_find_prt_entry(int segment,
51							  int bus,
52							  int device, int pin)
53{
54	struct list_head *node = NULL;
55	struct acpi_prt_entry *entry = NULL;
56
57
58	if (!acpi_prt.count)
59		return NULL;
60
61	/*
62	 * Parse through all PRT entries looking for a match on the specified
63	 * PCI device's segment, bus, device, and pin (don't care about func).
64	 *
65	 */
66	spin_lock(&acpi_prt_lock);
67	list_for_each(node, &acpi_prt.entries) {
68		entry = list_entry(node, struct acpi_prt_entry, node);
69		if ((segment == entry->id.segment)
70		    && (bus == entry->id.bus)
71		    && (device == entry->id.device)
72		    && (pin == entry->pin)) {
73			spin_unlock(&acpi_prt_lock);
74			return entry;
75		}
76	}
77
78	spin_unlock(&acpi_prt_lock);
79	return NULL;
80}
81
82static int
83acpi_pci_irq_add_entry(acpi_handle handle,
84		       int segment, int bus, struct acpi_pci_routing_table *prt)
85{
86	struct acpi_prt_entry *entry = NULL;
87
88
89	if (!prt)
90		return -EINVAL;
91
92	entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
93	if (!entry)
94		return -ENOMEM;
95
96	entry->id.segment = segment;
97	entry->id.bus = bus;
98	entry->id.device = (prt->address >> 16) & 0xFFFF;
99	entry->id.function = prt->address & 0xFFFF;
100	entry->pin = prt->pin;
101
102	/*
103	 * Type 1: Dynamic
104	 * ---------------
105	 * The 'source' field specifies the PCI interrupt link device used to
106	 * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
107	 * indicates which resource descriptor in the resource template (of
108	 * the link device) this interrupt is allocated from.
109	 *
110	 * NOTE: Don't query the Link Device for IRQ information at this time
111	 *       because Link Device enumeration may not have occurred yet
112	 *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
113	 *       namespace).
114	 */
115	if (prt->source[0]) {
116		acpi_get_handle(handle, prt->source, &entry->link.handle);
117		entry->link.index = prt->source_index;
118	}
119	/*
120	 * Type 2: Static
121	 * --------------
122	 * The 'source' field is NULL, and the 'source_index' field specifies
123	 * the IRQ value, which is hardwired to specific interrupt inputs on
124	 * the interrupt controller.
125	 */
126	else
127		entry->link.index = prt->source_index;
128
129	ACPI_DEBUG_PRINT_RAW((ACPI_DB_INFO,
130			      "      %02X:%02X:%02X[%c] -> %s[%d]\n",
131			      entry->id.segment, entry->id.bus,
132			      entry->id.device, ('A' + entry->pin), prt->source,
133			      entry->link.index));
134
135	spin_lock(&acpi_prt_lock);
136	list_add_tail(&entry->node, &acpi_prt.entries);
137	acpi_prt.count++;
138	spin_unlock(&acpi_prt_lock);
139
140	return 0;
141}
142
143static void
144acpi_pci_irq_del_entry(int segment, int bus, struct acpi_prt_entry *entry)
145{
146	if (segment == entry->id.segment && bus == entry->id.bus) {
147		acpi_prt.count--;
148		list_del(&entry->node);
149		kfree(entry);
150	}
151}
152
153int acpi_pci_irq_add_prt(acpi_handle handle, int segment, int bus)
154{
155	acpi_status status = AE_OK;
156	char *pathname = NULL;
157	struct acpi_buffer buffer = { 0, NULL };
158	struct acpi_pci_routing_table *prt = NULL;
159	struct acpi_pci_routing_table *entry = NULL;
160	static int first_time = 1;
161
162
163	pathname = kzalloc(ACPI_PATHNAME_MAX, GFP_KERNEL);
164	if (!pathname)
165		return -ENOMEM;
166
167	if (first_time) {
168		acpi_prt.count = 0;
169		INIT_LIST_HEAD(&acpi_prt.entries);
170		first_time = 0;
171	}
172
173	/*
174	 * NOTE: We're given a 'handle' to the _PRT object's parent device
175	 *       (either a PCI root bridge or PCI-PCI bridge).
176	 */
177
178	buffer.length = ACPI_PATHNAME_MAX;
179	buffer.pointer = pathname;
180	acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer);
181
182	printk(KERN_DEBUG "ACPI: PCI Interrupt Routing Table [%s._PRT]\n",
183	       pathname);
184
185	/*
186	 * Evaluate this _PRT and add its entries to our global list (acpi_prt).
187	 */
188
189	buffer.length = 0;
190	buffer.pointer = NULL;
191	kfree(pathname);
192	status = acpi_get_irq_routing_table(handle, &buffer);
193	if (status != AE_BUFFER_OVERFLOW) {
194		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
195				acpi_format_exception(status)));
196		return -ENODEV;
197	}
198
199	prt = kzalloc(buffer.length, GFP_KERNEL);
200	if (!prt) {
201		return -ENOMEM;
202	}
203	buffer.pointer = prt;
204
205	status = acpi_get_irq_routing_table(handle, &buffer);
206	if (ACPI_FAILURE(status)) {
207		ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PRT [%s]",
208				acpi_format_exception(status)));
209		kfree(buffer.pointer);
210		return -ENODEV;
211	}
212
213	entry = prt;
214
215	while (entry && (entry->length > 0)) {
216		acpi_pci_irq_add_entry(handle, segment, bus, entry);
217		entry = (struct acpi_pci_routing_table *)
218		    ((unsigned long)entry + entry->length);
219	}
220
221	kfree(prt);
222
223	return 0;
224}
225
226void acpi_pci_irq_del_prt(int segment, int bus)
227{
228	struct list_head *node = NULL, *n = NULL;
229	struct acpi_prt_entry *entry = NULL;
230
231	if (!acpi_prt.count) {
232		return;
233	}
234
235	printk(KERN_DEBUG
236	       "ACPI: Delete PCI Interrupt Routing Table for %x:%x\n", segment,
237	       bus);
238	spin_lock(&acpi_prt_lock);
239	list_for_each_safe(node, n, &acpi_prt.entries) {
240		entry = list_entry(node, struct acpi_prt_entry, node);
241
242		acpi_pci_irq_del_entry(segment, bus, entry);
243	}
244	spin_unlock(&acpi_prt_lock);
245}
246
247/* --------------------------------------------------------------------------
248                          PCI Interrupt Routing Support
249   -------------------------------------------------------------------------- */
250typedef int (*irq_lookup_func) (struct acpi_prt_entry *, int *, int *, char **);
251
252static int
253acpi_pci_allocate_irq(struct acpi_prt_entry *entry,
254		      int *triggering, int *polarity, char **link)
255{
256	int irq;
257
258
259	if (entry->link.handle) {
260		irq = acpi_pci_link_allocate_irq(entry->link.handle,
261						 entry->link.index, triggering,
262						 polarity, link);
263		if (irq < 0) {
264			printk(KERN_WARNING PREFIX
265				      "Invalid IRQ link routing entry\n");
266			return -1;
267		}
268	} else {
269		irq = entry->link.index;
270		*triggering = ACPI_LEVEL_SENSITIVE;
271		*polarity = ACPI_ACTIVE_LOW;
272	}
273
274	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found IRQ %d\n", irq));
275	return irq;
276}
277
278static int
279acpi_pci_free_irq(struct acpi_prt_entry *entry,
280		  int *triggering, int *polarity, char **link)
281{
282	int irq;
283
284	if (entry->link.handle) {
285		irq = acpi_pci_link_free_irq(entry->link.handle);
286	} else {
287		irq = entry->link.index;
288	}
289	return irq;
290}
291
292/*
293 * acpi_pci_irq_lookup
294 * success: return IRQ >= 0
295 * failure: return -1
296 */
297static int
298acpi_pci_irq_lookup(struct pci_bus *bus,
299		    int device,
300		    int pin,
301		    int *triggering,
302		    int *polarity, char **link, irq_lookup_func func)
303{
304	struct acpi_prt_entry *entry = NULL;
305	int segment = pci_domain_nr(bus);
306	int bus_nr = bus->number;
307	int ret;
308
309
310	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
311			  "Searching for PRT entry for %02x:%02x:%02x[%c]\n",
312			  segment, bus_nr, device, ('A' + pin)));
313
314	entry = acpi_pci_irq_find_prt_entry(segment, bus_nr, device, pin);
315	if (!entry) {
316		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "PRT entry not found\n"));
317		return -1;
318	}
319
320	ret = func(entry, triggering, polarity, link);
321	return ret;
322}
323
324/*
325 * acpi_pci_irq_derive
326 * success: return IRQ >= 0
327 * failure: return < 0
328 */
329static int
330acpi_pci_irq_derive(struct pci_dev *dev,
331		    int pin,
332		    int *triggering,
333		    int *polarity, char **link, irq_lookup_func func)
334{
335	struct pci_dev *bridge = dev;
336	int irq = -1;
337	u8 bridge_pin = 0;
338
339
340	if (!dev)
341		return -EINVAL;
342
343	/*
344	 * Attempt to derive an IRQ for this device from a parent bridge's
345	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
346	 */
347	while (irq < 0 && bridge->bus->self) {
348		pin = (pin + PCI_SLOT(bridge->devfn)) % 4;
349		bridge = bridge->bus->self;
350
351		if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
352			/* PC card has the same IRQ as its cardbridge */
353			bridge_pin = bridge->pin;
354			if (!bridge_pin) {
355				ACPI_DEBUG_PRINT((ACPI_DB_INFO,
356						  "No interrupt pin configured for device %s\n",
357						  pci_name(bridge)));
358				return -1;
359			}
360			/* Pin is from 0 to 3 */
361			bridge_pin--;
362			pin = bridge_pin;
363		}
364
365		irq = acpi_pci_irq_lookup(bridge->bus, PCI_SLOT(bridge->devfn),
366					  pin, triggering, polarity,
367					  link, func);
368	}
369
370	if (irq < 0) {
371		printk(KERN_WARNING PREFIX "Unable to derive IRQ for device %s\n",
372			      pci_name(dev));
373		return -1;
374	}
375
376	ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Derive IRQ %d for device %s from %s\n",
377			  irq, pci_name(dev), pci_name(bridge)));
378
379	return irq;
380}
381
382/*
383 * acpi_pci_irq_enable
384 * success: return 0
385 * failure: return < 0
386 */
387
388int acpi_pci_irq_enable(struct pci_dev *dev)
389{
390	int irq = 0;
391	u8 pin = 0;
392	int triggering = ACPI_LEVEL_SENSITIVE;
393	int polarity = ACPI_ACTIVE_LOW;
394	char *link = NULL;
395	int rc;
396
397
398	if (!dev)
399		return -EINVAL;
400
401	pin = dev->pin;
402	if (!pin) {
403		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
404				  "No interrupt pin configured for device %s\n",
405				  pci_name(dev)));
406		return 0;
407	}
408	pin--;
409
410	if (!dev->bus) {
411		printk(KERN_ERR PREFIX "Invalid (NULL) 'bus' field\n");
412		return -ENODEV;
413	}
414
415	/*
416	 * First we check the PCI IRQ routing table (PRT) for an IRQ.  PRT
417	 * values override any BIOS-assigned IRQs set during boot.
418	 */
419	irq = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
420				  &triggering, &polarity, &link,
421				  acpi_pci_allocate_irq);
422
423	/*
424	 * If no PRT entry was found, we'll try to derive an IRQ from the
425	 * device's parent bridge.
426	 */
427	if (irq < 0)
428		irq = acpi_pci_irq_derive(dev, pin, &triggering,
429					  &polarity, &link,
430					  acpi_pci_allocate_irq);
431
432	/*
433	 * No IRQ known to the ACPI subsystem - maybe the BIOS /
434	 * driver reported one, then use it. Exit in any case.
435	 */
436	if (irq < 0) {
437		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: no GSI",
438		       pci_name(dev), ('A' + pin));
439		/* Interrupt Line values above 0xF are forbidden */
440		if (dev->irq > 0 && (dev->irq <= 0xF)) {
441			printk(" - using IRQ %d\n", dev->irq);
442			acpi_register_gsi(dev->irq, ACPI_LEVEL_SENSITIVE,
443					  ACPI_ACTIVE_LOW);
444			return 0;
445		} else {
446			printk("\n");
447			return 0;
448		}
449	}
450
451	rc = acpi_register_gsi(irq, triggering, polarity);
452	if (rc < 0) {
453		printk(KERN_WARNING PREFIX "PCI Interrupt %s[%c]: failed "
454		       "to register GSI\n", pci_name(dev), ('A' + pin));
455		return rc;
456	}
457	dev->irq = rc;
458
459	printk(KERN_INFO PREFIX "PCI Interrupt %s[%c] -> ",
460	       pci_name(dev), 'A' + pin);
461
462	if (link)
463		printk("Link [%s] -> ", link);
464
465	printk("GSI %u (%s, %s) -> IRQ %d\n", irq,
466	       (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
467	       (polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);
468
469	return 0;
470}
471
472EXPORT_SYMBOL(acpi_pci_irq_enable);
473
474void __attribute__ ((weak)) acpi_unregister_gsi(u32 i)
475{
476}
477
478void acpi_pci_irq_disable(struct pci_dev *dev)
479{
480	int gsi = 0;
481	u8 pin = 0;
482	int triggering = ACPI_LEVEL_SENSITIVE;
483	int polarity = ACPI_ACTIVE_LOW;
484
485
486	if (!dev || !dev->bus)
487		return;
488
489	pin = dev->pin;
490	if (!pin)
491		return;
492	pin--;
493
494	/*
495	 * First we check the PCI IRQ routing table (PRT) for an IRQ.
496	 */
497	gsi = acpi_pci_irq_lookup(dev->bus, PCI_SLOT(dev->devfn), pin,
498				  &triggering, &polarity, NULL,
499				  acpi_pci_free_irq);
500	/*
501	 * If no PRT entry was found, we'll try to derive an IRQ from the
502	 * device's parent bridge.
503	 */
504	if (gsi < 0)
505		gsi = acpi_pci_irq_derive(dev, pin,
506					  &triggering, &polarity, NULL,
507					  acpi_pci_free_irq);
508	if (gsi < 0)
509		return;
510
511	/*
512	 * TBD: It might be worth clearing dev->irq by magic constant
513	 * (e.g. PCI_UNDEFINED_IRQ).
514	 */
515
516	printk(KERN_INFO PREFIX "PCI interrupt for device %s disabled\n",
517	       pci_name(dev));
518
519	acpi_unregister_gsi(gsi);
520
521	return;
522}
523