xref: /openbmc/linux/arch/x86/pci/irq.c (revision 22246614)
1 /*
2  *	Low-Level PCI Support for PC -- Routing of Interrupts
3  *
4  *	(c) 1999--2000 Martin Mares <mj@ucw.cz>
5  */
6 
7 #include <linux/types.h>
8 #include <linux/kernel.h>
9 #include <linux/pci.h>
10 #include <linux/init.h>
11 #include <linux/slab.h>
12 #include <linux/interrupt.h>
13 #include <linux/dmi.h>
14 #include <asm/io.h>
15 #include <asm/smp.h>
16 #include <asm/io_apic.h>
17 #include <linux/irq.h>
18 #include <linux/acpi.h>
19 
20 #include "pci.h"
21 
22 #define PIRQ_SIGNATURE	(('$' << 0) + ('P' << 8) + ('I' << 16) + ('R' << 24))
23 #define PIRQ_VERSION 0x0100
24 
25 static int broken_hp_bios_irq9;
26 static int acer_tm360_irqrouting;
27 
28 static struct irq_routing_table *pirq_table;
29 
30 static int pirq_enable_irq(struct pci_dev *dev);
31 
32 /*
33  * Never use: 0, 1, 2 (timer, keyboard, and cascade)
34  * Avoid using: 13, 14 and 15 (FP error and IDE).
35  * Penalize: 3, 4, 6, 7, 12 (known ISA uses: serial, floppy, parallel and mouse)
36  */
37 unsigned int pcibios_irq_mask = 0xfff8;
38 
39 static int pirq_penalty[16] = {
40 	1000000, 1000000, 1000000, 1000, 1000, 0, 1000, 1000,
41 	0, 0, 0, 0, 1000, 100000, 100000, 100000
42 };
43 
44 struct irq_router {
45 	char *name;
46 	u16 vendor, device;
47 	int (*get)(struct pci_dev *router, struct pci_dev *dev, int pirq);
48 	int (*set)(struct pci_dev *router, struct pci_dev *dev, int pirq, int new);
49 };
50 
51 struct irq_router_handler {
52 	u16 vendor;
53 	int (*probe)(struct irq_router *r, struct pci_dev *router, u16 device);
54 };
55 
56 int (*pcibios_enable_irq)(struct pci_dev *dev) = NULL;
57 void (*pcibios_disable_irq)(struct pci_dev *dev) = NULL;
58 
59 /*
60  *  Check passed address for the PCI IRQ Routing Table signature
61  *  and perform checksum verification.
62  */
63 
64 static inline struct irq_routing_table * pirq_check_routing_table(u8 *addr)
65 {
66 	struct irq_routing_table *rt;
67 	int i;
68 	u8 sum;
69 
70 	rt = (struct irq_routing_table *) addr;
71 	if (rt->signature != PIRQ_SIGNATURE ||
72 	    rt->version != PIRQ_VERSION ||
73 	    rt->size % 16 ||
74 	    rt->size < sizeof(struct irq_routing_table))
75 		return NULL;
76 	sum = 0;
77 	for (i=0; i < rt->size; i++)
78 		sum += addr[i];
79 	if (!sum) {
80 		DBG(KERN_DEBUG "PCI: Interrupt Routing Table found at 0x%p\n", rt);
81 		return rt;
82 	}
83 	return NULL;
84 }
85 
86 
87 
88 /*
89  *  Search 0xf0000 -- 0xfffff for the PCI IRQ Routing Table.
90  */
91 
92 static struct irq_routing_table * __init pirq_find_routing_table(void)
93 {
94 	u8 *addr;
95 	struct irq_routing_table *rt;
96 
97 	if (pirq_table_addr) {
98 		rt = pirq_check_routing_table((u8 *) __va(pirq_table_addr));
99 		if (rt)
100 			return rt;
101 		printk(KERN_WARNING "PCI: PIRQ table NOT found at pirqaddr\n");
102 	}
103 	for(addr = (u8 *) __va(0xf0000); addr < (u8 *) __va(0x100000); addr += 16) {
104 		rt = pirq_check_routing_table(addr);
105 		if (rt)
106 			return rt;
107 	}
108 	return NULL;
109 }
110 
111 /*
112  *  If we have a IRQ routing table, use it to search for peer host
113  *  bridges.  It's a gross hack, but since there are no other known
114  *  ways how to get a list of buses, we have to go this way.
115  */
116 
117 static void __init pirq_peer_trick(void)
118 {
119 	struct irq_routing_table *rt = pirq_table;
120 	u8 busmap[256];
121 	int i;
122 	struct irq_info *e;
123 
124 	memset(busmap, 0, sizeof(busmap));
125 	for(i=0; i < (rt->size - sizeof(struct irq_routing_table)) / sizeof(struct irq_info); i++) {
126 		e = &rt->slots[i];
127 #ifdef DEBUG
128 		{
129 			int j;
130 			DBG(KERN_DEBUG "%02x:%02x slot=%02x", e->bus, e->devfn/8, e->slot);
131 			for(j=0; j<4; j++)
132 				DBG(" %d:%02x/%04x", j, e->irq[j].link, e->irq[j].bitmap);
133 			DBG("\n");
134 		}
135 #endif
136 		busmap[e->bus] = 1;
137 	}
138 	for(i = 1; i < 256; i++) {
139 		int node;
140 		if (!busmap[i] || pci_find_bus(0, i))
141 			continue;
142 		node = get_mp_bus_to_node(i);
143 		if (pci_scan_bus_on_node(i, &pci_root_ops, node))
144 			printk(KERN_INFO "PCI: Discovered primary peer "
145 			       "bus %02x [IRQ]\n", i);
146 	}
147 	pcibios_last_bus = -1;
148 }
149 
150 /*
151  *  Code for querying and setting of IRQ routes on various interrupt routers.
152  */
153 
154 void eisa_set_level_irq(unsigned int irq)
155 {
156 	unsigned char mask = 1 << (irq & 7);
157 	unsigned int port = 0x4d0 + (irq >> 3);
158 	unsigned char val;
159 	static u16 eisa_irq_mask;
160 
161 	if (irq >= 16 || (1 << irq) & eisa_irq_mask)
162 		return;
163 
164 	eisa_irq_mask |= (1 << irq);
165 	printk(KERN_DEBUG "PCI: setting IRQ %u as level-triggered\n", irq);
166 	val = inb(port);
167 	if (!(val & mask)) {
168 		DBG(KERN_DEBUG " -> edge");
169 		outb(val | mask, port);
170 	}
171 }
172 
173 /*
174  * Common IRQ routing practice: nibbles in config space,
175  * offset by some magic constant.
176  */
177 static unsigned int read_config_nybble(struct pci_dev *router, unsigned offset, unsigned nr)
178 {
179 	u8 x;
180 	unsigned reg = offset + (nr >> 1);
181 
182 	pci_read_config_byte(router, reg, &x);
183 	return (nr & 1) ? (x >> 4) : (x & 0xf);
184 }
185 
186 static void write_config_nybble(struct pci_dev *router, unsigned offset, unsigned nr, unsigned int val)
187 {
188 	u8 x;
189 	unsigned reg = offset + (nr >> 1);
190 
191 	pci_read_config_byte(router, reg, &x);
192 	x = (nr & 1) ? ((x & 0x0f) | (val << 4)) : ((x & 0xf0) | val);
193 	pci_write_config_byte(router, reg, x);
194 }
195 
196 /*
197  * ALI pirq entries are damn ugly, and completely undocumented.
198  * This has been figured out from pirq tables, and it's not a pretty
199  * picture.
200  */
201 static int pirq_ali_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
202 {
203 	static const unsigned char irqmap[16] = { 0, 9, 3, 10, 4, 5, 7, 6, 1, 11, 0, 12, 0, 14, 0, 15 };
204 
205 	WARN_ON_ONCE(pirq > 16);
206 	return irqmap[read_config_nybble(router, 0x48, pirq-1)];
207 }
208 
209 static int pirq_ali_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
210 {
211 	static const unsigned char irqmap[16] = { 0, 8, 0, 2, 4, 5, 7, 6, 0, 1, 3, 9, 11, 0, 13, 15 };
212 	unsigned int val = irqmap[irq];
213 
214 	WARN_ON_ONCE(pirq > 16);
215 	if (val) {
216 		write_config_nybble(router, 0x48, pirq-1, val);
217 		return 1;
218 	}
219 	return 0;
220 }
221 
222 /*
223  * The Intel PIIX4 pirq rules are fairly simple: "pirq" is
224  * just a pointer to the config space.
225  */
226 static int pirq_piix_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
227 {
228 	u8 x;
229 
230 	pci_read_config_byte(router, pirq, &x);
231 	return (x < 16) ? x : 0;
232 }
233 
234 static int pirq_piix_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
235 {
236 	pci_write_config_byte(router, pirq, irq);
237 	return 1;
238 }
239 
240 /*
241  * The VIA pirq rules are nibble-based, like ALI,
242  * but without the ugly irq number munging.
243  * However, PIRQD is in the upper instead of lower 4 bits.
244  */
245 static int pirq_via_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
246 {
247 	return read_config_nybble(router, 0x55, pirq == 4 ? 5 : pirq);
248 }
249 
250 static int pirq_via_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
251 {
252 	write_config_nybble(router, 0x55, pirq == 4 ? 5 : pirq, irq);
253 	return 1;
254 }
255 
256 /*
257  * The VIA pirq rules are nibble-based, like ALI,
258  * but without the ugly irq number munging.
259  * However, for 82C586, nibble map is different .
260  */
261 static int pirq_via586_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
262 {
263 	static const unsigned int pirqmap[5] = { 3, 2, 5, 1, 1 };
264 
265 	WARN_ON_ONCE(pirq > 5);
266 	return read_config_nybble(router, 0x55, pirqmap[pirq-1]);
267 }
268 
269 static int pirq_via586_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
270 {
271 	static const unsigned int pirqmap[5] = { 3, 2, 5, 1, 1 };
272 
273 	WARN_ON_ONCE(pirq > 5);
274 	write_config_nybble(router, 0x55, pirqmap[pirq-1], irq);
275 	return 1;
276 }
277 
278 /*
279  * ITE 8330G pirq rules are nibble-based
280  * FIXME: pirqmap may be { 1, 0, 3, 2 },
281  * 	  2+3 are both mapped to irq 9 on my system
282  */
283 static int pirq_ite_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
284 {
285 	static const unsigned char pirqmap[4] = { 1, 0, 2, 3 };
286 
287 	WARN_ON_ONCE(pirq > 4);
288 	return read_config_nybble(router,0x43, pirqmap[pirq-1]);
289 }
290 
291 static int pirq_ite_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
292 {
293 	static const unsigned char pirqmap[4] = { 1, 0, 2, 3 };
294 
295 	WARN_ON_ONCE(pirq > 4);
296 	write_config_nybble(router, 0x43, pirqmap[pirq-1], irq);
297 	return 1;
298 }
299 
300 /*
301  * OPTI: high four bits are nibble pointer..
302  * I wonder what the low bits do?
303  */
304 static int pirq_opti_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
305 {
306 	return read_config_nybble(router, 0xb8, pirq >> 4);
307 }
308 
309 static int pirq_opti_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
310 {
311 	write_config_nybble(router, 0xb8, pirq >> 4, irq);
312 	return 1;
313 }
314 
315 /*
316  * Cyrix: nibble offset 0x5C
317  * 0x5C bits 7:4 is INTB bits 3:0 is INTA
318  * 0x5D bits 7:4 is INTD bits 3:0 is INTC
319  */
320 static int pirq_cyrix_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
321 {
322 	return read_config_nybble(router, 0x5C, (pirq-1)^1);
323 }
324 
325 static int pirq_cyrix_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
326 {
327 	write_config_nybble(router, 0x5C, (pirq-1)^1, irq);
328 	return 1;
329 }
330 
331 /*
332  *	PIRQ routing for SiS 85C503 router used in several SiS chipsets.
333  *	We have to deal with the following issues here:
334  *	- vendors have different ideas about the meaning of link values
335  *	- some onboard devices (integrated in the chipset) have special
336  *	  links and are thus routed differently (i.e. not via PCI INTA-INTD)
337  *	- different revision of the router have a different layout for
338  *	  the routing registers, particularly for the onchip devices
339  *
340  *	For all routing registers the common thing is we have one byte
341  *	per routeable link which is defined as:
342  *		 bit 7      IRQ mapping enabled (0) or disabled (1)
343  *		 bits [6:4] reserved (sometimes used for onchip devices)
344  *		 bits [3:0] IRQ to map to
345  *		     allowed: 3-7, 9-12, 14-15
346  *		     reserved: 0, 1, 2, 8, 13
347  *
348  *	The config-space registers located at 0x41/0x42/0x43/0x44 are
349  *	always used to route the normal PCI INT A/B/C/D respectively.
350  *	Apparently there are systems implementing PCI routing table using
351  *	link values 0x01-0x04 and others using 0x41-0x44 for PCI INTA..D.
352  *	We try our best to handle both link mappings.
353  *
354  *	Currently (2003-05-21) it appears most SiS chipsets follow the
355  *	definition of routing registers from the SiS-5595 southbridge.
356  *	According to the SiS 5595 datasheets the revision id's of the
357  *	router (ISA-bridge) should be 0x01 or 0xb0.
358  *
359  *	Furthermore we've also seen lspci dumps with revision 0x00 and 0xb1.
360  *	Looks like these are used in a number of SiS 5xx/6xx/7xx chipsets.
361  *	They seem to work with the current routing code. However there is
362  *	some concern because of the two USB-OHCI HCs (original SiS 5595
363  *	had only one). YMMV.
364  *
365  *	Onchip routing for router rev-id 0x01/0xb0 and probably 0x00/0xb1:
366  *
367  *	0x61:	IDEIRQ:
368  *		bits [6:5] must be written 01
369  *		bit 4 channel-select primary (0), secondary (1)
370  *
371  *	0x62:	USBIRQ:
372  *		bit 6 OHCI function disabled (0), enabled (1)
373  *
374  *	0x6a:	ACPI/SCI IRQ: bits 4-6 reserved
375  *
376  *	0x7e:	Data Acq. Module IRQ - bits 4-6 reserved
377  *
378  *	We support USBIRQ (in addition to INTA-INTD) and keep the
379  *	IDE, ACPI and DAQ routing untouched as set by the BIOS.
380  *
381  *	Currently the only reported exception is the new SiS 65x chipset
382  *	which includes the SiS 69x southbridge. Here we have the 85C503
383  *	router revision 0x04 and there are changes in the register layout
384  *	mostly related to the different USB HCs with USB 2.0 support.
385  *
386  *	Onchip routing for router rev-id 0x04 (try-and-error observation)
387  *
388  *	0x60/0x61/0x62/0x63:	1xEHCI and 3xOHCI (companion) USB-HCs
389  *				bit 6-4 are probably unused, not like 5595
390  */
391 
392 #define PIRQ_SIS_IRQ_MASK	0x0f
393 #define PIRQ_SIS_IRQ_DISABLE	0x80
394 #define PIRQ_SIS_USB_ENABLE	0x40
395 
396 static int pirq_sis_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
397 {
398 	u8 x;
399 	int reg;
400 
401 	reg = pirq;
402 	if (reg >= 0x01 && reg <= 0x04)
403 		reg += 0x40;
404 	pci_read_config_byte(router, reg, &x);
405 	return (x & PIRQ_SIS_IRQ_DISABLE) ? 0 : (x & PIRQ_SIS_IRQ_MASK);
406 }
407 
408 static int pirq_sis_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
409 {
410 	u8 x;
411 	int reg;
412 
413 	reg = pirq;
414 	if (reg >= 0x01 && reg <= 0x04)
415 		reg += 0x40;
416 	pci_read_config_byte(router, reg, &x);
417 	x &= ~(PIRQ_SIS_IRQ_MASK | PIRQ_SIS_IRQ_DISABLE);
418 	x |= irq ? irq: PIRQ_SIS_IRQ_DISABLE;
419 	pci_write_config_byte(router, reg, x);
420 	return 1;
421 }
422 
423 
424 /*
425  * VLSI: nibble offset 0x74 - educated guess due to routing table and
426  *       config space of VLSI 82C534 PCI-bridge/router (1004:0102)
427  *       Tested on HP OmniBook 800 covering PIRQ 1, 2, 4, 8 for onboard
428  *       devices, PIRQ 3 for non-pci(!) soundchip and (untested) PIRQ 6
429  *       for the busbridge to the docking station.
430  */
431 
432 static int pirq_vlsi_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
433 {
434 	WARN_ON_ONCE(pirq >= 9);
435 	if (pirq > 8) {
436 		printk(KERN_INFO "VLSI router pirq escape (%d)\n", pirq);
437 		return 0;
438 	}
439 	return read_config_nybble(router, 0x74, pirq-1);
440 }
441 
442 static int pirq_vlsi_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
443 {
444 	WARN_ON_ONCE(pirq >= 9);
445 	if (pirq > 8) {
446 		printk(KERN_INFO "VLSI router pirq escape (%d)\n", pirq);
447 		return 0;
448 	}
449 	write_config_nybble(router, 0x74, pirq-1, irq);
450 	return 1;
451 }
452 
453 /*
454  * ServerWorks: PCI interrupts mapped to system IRQ lines through Index
455  * and Redirect I/O registers (0x0c00 and 0x0c01).  The Index register
456  * format is (PCIIRQ## | 0x10), e.g.: PCIIRQ10=0x1a.  The Redirect
457  * register is a straight binary coding of desired PIC IRQ (low nibble).
458  *
459  * The 'link' value in the PIRQ table is already in the correct format
460  * for the Index register.  There are some special index values:
461  * 0x00 for ACPI (SCI), 0x01 for USB, 0x02 for IDE0, 0x04 for IDE1,
462  * and 0x03 for SMBus.
463  */
464 static int pirq_serverworks_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
465 {
466 	outb(pirq, 0xc00);
467 	return inb(0xc01) & 0xf;
468 }
469 
470 static int pirq_serverworks_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
471 {
472 	outb(pirq, 0xc00);
473 	outb(irq, 0xc01);
474 	return 1;
475 }
476 
477 /* Support for AMD756 PCI IRQ Routing
478  * Jhon H. Caicedo <jhcaiced@osso.org.co>
479  * Jun/21/2001 0.2.0 Release, fixed to use "nybble" functions... (jhcaiced)
480  * Jun/19/2001 Alpha Release 0.1.0 (jhcaiced)
481  * The AMD756 pirq rules are nibble-based
482  * offset 0x56 0-3 PIRQA  4-7  PIRQB
483  * offset 0x57 0-3 PIRQC  4-7  PIRQD
484  */
485 static int pirq_amd756_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
486 {
487 	u8 irq;
488 	irq = 0;
489 	if (pirq <= 4)
490 	{
491 		irq = read_config_nybble(router, 0x56, pirq - 1);
492 	}
493 	printk(KERN_INFO "AMD756: dev %04x:%04x, router pirq : %d get irq : %2d\n",
494 		dev->vendor, dev->device, pirq, irq);
495 	return irq;
496 }
497 
498 static int pirq_amd756_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
499 {
500 	printk(KERN_INFO "AMD756: dev %04x:%04x, router pirq : %d SET irq : %2d\n",
501 		dev->vendor, dev->device, pirq, irq);
502 	if (pirq <= 4)
503 	{
504 		write_config_nybble(router, 0x56, pirq - 1, irq);
505 	}
506 	return 1;
507 }
508 
509 /*
510  * PicoPower PT86C523
511  */
512 static int pirq_pico_get(struct pci_dev *router, struct pci_dev *dev, int pirq)
513 {
514 	outb(0x10 + ((pirq - 1) >> 1), 0x24);
515 	return ((pirq - 1) & 1) ? (inb(0x26) >> 4) : (inb(0x26) & 0xf);
516 }
517 
518 static int pirq_pico_set(struct pci_dev *router, struct pci_dev *dev, int pirq,
519 			int irq)
520 {
521 	unsigned int x;
522 	outb(0x10 + ((pirq - 1) >> 1), 0x24);
523 	x = inb(0x26);
524 	x = ((pirq - 1) & 1) ? ((x & 0x0f) | (irq << 4)) : ((x & 0xf0) | (irq));
525 	outb(x, 0x26);
526 	return 1;
527 }
528 
529 #ifdef CONFIG_PCI_BIOS
530 
531 static int pirq_bios_set(struct pci_dev *router, struct pci_dev *dev, int pirq, int irq)
532 {
533 	struct pci_dev *bridge;
534 	int pin = pci_get_interrupt_pin(dev, &bridge);
535 	return pcibios_set_irq_routing(bridge, pin, irq);
536 }
537 
538 #endif
539 
540 static __init int intel_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
541 {
542 	static struct pci_device_id __initdata pirq_440gx[] = {
543 		{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443GX_0) },
544 		{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_82443GX_2) },
545 		{ },
546 	};
547 
548 	/* 440GX has a proprietary PIRQ router -- don't use it */
549 	if (pci_dev_present(pirq_440gx))
550 		return 0;
551 
552 	switch(device)
553 	{
554 		case PCI_DEVICE_ID_INTEL_82371FB_0:
555 		case PCI_DEVICE_ID_INTEL_82371SB_0:
556 		case PCI_DEVICE_ID_INTEL_82371AB_0:
557 		case PCI_DEVICE_ID_INTEL_82371MX:
558 		case PCI_DEVICE_ID_INTEL_82443MX_0:
559 		case PCI_DEVICE_ID_INTEL_82801AA_0:
560 		case PCI_DEVICE_ID_INTEL_82801AB_0:
561 		case PCI_DEVICE_ID_INTEL_82801BA_0:
562 		case PCI_DEVICE_ID_INTEL_82801BA_10:
563 		case PCI_DEVICE_ID_INTEL_82801CA_0:
564 		case PCI_DEVICE_ID_INTEL_82801CA_12:
565 		case PCI_DEVICE_ID_INTEL_82801DB_0:
566 		case PCI_DEVICE_ID_INTEL_82801E_0:
567 		case PCI_DEVICE_ID_INTEL_82801EB_0:
568 		case PCI_DEVICE_ID_INTEL_ESB_1:
569 		case PCI_DEVICE_ID_INTEL_ICH6_0:
570 		case PCI_DEVICE_ID_INTEL_ICH6_1:
571 		case PCI_DEVICE_ID_INTEL_ICH7_0:
572 		case PCI_DEVICE_ID_INTEL_ICH7_1:
573 		case PCI_DEVICE_ID_INTEL_ICH7_30:
574 		case PCI_DEVICE_ID_INTEL_ICH7_31:
575 		case PCI_DEVICE_ID_INTEL_ESB2_0:
576 		case PCI_DEVICE_ID_INTEL_ICH8_0:
577 		case PCI_DEVICE_ID_INTEL_ICH8_1:
578 		case PCI_DEVICE_ID_INTEL_ICH8_2:
579 		case PCI_DEVICE_ID_INTEL_ICH8_3:
580 		case PCI_DEVICE_ID_INTEL_ICH8_4:
581 		case PCI_DEVICE_ID_INTEL_ICH9_0:
582 		case PCI_DEVICE_ID_INTEL_ICH9_1:
583 		case PCI_DEVICE_ID_INTEL_ICH9_2:
584 		case PCI_DEVICE_ID_INTEL_ICH9_3:
585 		case PCI_DEVICE_ID_INTEL_ICH9_4:
586 		case PCI_DEVICE_ID_INTEL_ICH9_5:
587 		case PCI_DEVICE_ID_INTEL_TOLAPAI_0:
588 		case PCI_DEVICE_ID_INTEL_ICH10_0:
589 		case PCI_DEVICE_ID_INTEL_ICH10_1:
590 		case PCI_DEVICE_ID_INTEL_ICH10_2:
591 		case PCI_DEVICE_ID_INTEL_ICH10_3:
592 			r->name = "PIIX/ICH";
593 			r->get = pirq_piix_get;
594 			r->set = pirq_piix_set;
595 			return 1;
596 	}
597 	return 0;
598 }
599 
600 static __init int via_router_probe(struct irq_router *r,
601 				struct pci_dev *router, u16 device)
602 {
603 	/* FIXME: We should move some of the quirk fixup stuff here */
604 
605 	/*
606 	 * workarounds for some buggy BIOSes
607 	 */
608 	if (device == PCI_DEVICE_ID_VIA_82C586_0) {
609 		switch(router->device) {
610 		case PCI_DEVICE_ID_VIA_82C686:
611 			/*
612 			 * Asus k7m bios wrongly reports 82C686A
613 			 * as 586-compatible
614 			 */
615 			device = PCI_DEVICE_ID_VIA_82C686;
616 			break;
617 		case PCI_DEVICE_ID_VIA_8235:
618 			/**
619 			 * Asus a7v-x bios wrongly reports 8235
620 			 * as 586-compatible
621 			 */
622 			device = PCI_DEVICE_ID_VIA_8235;
623 			break;
624 		}
625 	}
626 
627 	switch(device) {
628 	case PCI_DEVICE_ID_VIA_82C586_0:
629 		r->name = "VIA";
630 		r->get = pirq_via586_get;
631 		r->set = pirq_via586_set;
632 		return 1;
633 	case PCI_DEVICE_ID_VIA_82C596:
634 	case PCI_DEVICE_ID_VIA_82C686:
635 	case PCI_DEVICE_ID_VIA_8231:
636 	case PCI_DEVICE_ID_VIA_8233A:
637 	case PCI_DEVICE_ID_VIA_8235:
638 	case PCI_DEVICE_ID_VIA_8237:
639 		/* FIXME: add new ones for 8233/5 */
640 		r->name = "VIA";
641 		r->get = pirq_via_get;
642 		r->set = pirq_via_set;
643 		return 1;
644 	}
645 	return 0;
646 }
647 
648 static __init int vlsi_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
649 {
650 	switch(device)
651 	{
652 		case PCI_DEVICE_ID_VLSI_82C534:
653 			r->name = "VLSI 82C534";
654 			r->get = pirq_vlsi_get;
655 			r->set = pirq_vlsi_set;
656 			return 1;
657 	}
658 	return 0;
659 }
660 
661 
662 static __init int serverworks_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
663 {
664 	switch(device)
665 	{
666 		case PCI_DEVICE_ID_SERVERWORKS_OSB4:
667 		case PCI_DEVICE_ID_SERVERWORKS_CSB5:
668 			r->name = "ServerWorks";
669 			r->get = pirq_serverworks_get;
670 			r->set = pirq_serverworks_set;
671 			return 1;
672 	}
673 	return 0;
674 }
675 
676 static __init int sis_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
677 {
678 	if (device != PCI_DEVICE_ID_SI_503)
679 		return 0;
680 
681 	r->name = "SIS";
682 	r->get = pirq_sis_get;
683 	r->set = pirq_sis_set;
684 	return 1;
685 }
686 
687 static __init int cyrix_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
688 {
689 	switch(device)
690 	{
691 		case PCI_DEVICE_ID_CYRIX_5520:
692 			r->name = "NatSemi";
693 			r->get = pirq_cyrix_get;
694 			r->set = pirq_cyrix_set;
695 			return 1;
696 	}
697 	return 0;
698 }
699 
700 static __init int opti_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
701 {
702 	switch(device)
703 	{
704 		case PCI_DEVICE_ID_OPTI_82C700:
705 			r->name = "OPTI";
706 			r->get = pirq_opti_get;
707 			r->set = pirq_opti_set;
708 			return 1;
709 	}
710 	return 0;
711 }
712 
713 static __init int ite_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
714 {
715 	switch(device)
716 	{
717 		case PCI_DEVICE_ID_ITE_IT8330G_0:
718 			r->name = "ITE";
719 			r->get = pirq_ite_get;
720 			r->set = pirq_ite_set;
721 			return 1;
722 	}
723 	return 0;
724 }
725 
726 static __init int ali_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
727 {
728 	switch(device)
729 	{
730 	case PCI_DEVICE_ID_AL_M1533:
731 	case PCI_DEVICE_ID_AL_M1563:
732 		printk(KERN_DEBUG "PCI: Using ALI IRQ Router\n");
733 		r->name = "ALI";
734 		r->get = pirq_ali_get;
735 		r->set = pirq_ali_set;
736 		return 1;
737 	}
738 	return 0;
739 }
740 
741 static __init int amd_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
742 {
743 	switch(device)
744 	{
745 		case PCI_DEVICE_ID_AMD_VIPER_740B:
746 			r->name = "AMD756";
747 			break;
748 		case PCI_DEVICE_ID_AMD_VIPER_7413:
749 			r->name = "AMD766";
750 			break;
751 		case PCI_DEVICE_ID_AMD_VIPER_7443:
752 			r->name = "AMD768";
753 			break;
754 		default:
755 			return 0;
756 	}
757 	r->get = pirq_amd756_get;
758 	r->set = pirq_amd756_set;
759 	return 1;
760 }
761 
762 static __init int pico_router_probe(struct irq_router *r, struct pci_dev *router, u16 device)
763 {
764 	switch (device) {
765 	case PCI_DEVICE_ID_PICOPOWER_PT86C523:
766 		r->name = "PicoPower PT86C523";
767 		r->get = pirq_pico_get;
768 		r->set = pirq_pico_set;
769 		return 1;
770 
771 	case PCI_DEVICE_ID_PICOPOWER_PT86C523BBP:
772 		r->name = "PicoPower PT86C523 rev. BB+";
773 		r->get = pirq_pico_get;
774 		r->set = pirq_pico_set;
775 		return 1;
776 	}
777 	return 0;
778 }
779 
780 static __initdata struct irq_router_handler pirq_routers[] = {
781 	{ PCI_VENDOR_ID_INTEL, intel_router_probe },
782 	{ PCI_VENDOR_ID_AL, ali_router_probe },
783 	{ PCI_VENDOR_ID_ITE, ite_router_probe },
784 	{ PCI_VENDOR_ID_VIA, via_router_probe },
785 	{ PCI_VENDOR_ID_OPTI, opti_router_probe },
786 	{ PCI_VENDOR_ID_SI, sis_router_probe },
787 	{ PCI_VENDOR_ID_CYRIX, cyrix_router_probe },
788 	{ PCI_VENDOR_ID_VLSI, vlsi_router_probe },
789 	{ PCI_VENDOR_ID_SERVERWORKS, serverworks_router_probe },
790 	{ PCI_VENDOR_ID_AMD, amd_router_probe },
791 	{ PCI_VENDOR_ID_PICOPOWER, pico_router_probe },
792 	/* Someone with docs needs to add the ATI Radeon IGP */
793 	{ 0, NULL }
794 };
795 static struct irq_router pirq_router;
796 static struct pci_dev *pirq_router_dev;
797 
798 
799 /*
800  *	FIXME: should we have an option to say "generic for
801  *	chipset" ?
802  */
803 
804 static void __init pirq_find_router(struct irq_router *r)
805 {
806 	struct irq_routing_table *rt = pirq_table;
807 	struct irq_router_handler *h;
808 
809 #ifdef CONFIG_PCI_BIOS
810 	if (!rt->signature) {
811 		printk(KERN_INFO "PCI: Using BIOS for IRQ routing\n");
812 		r->set = pirq_bios_set;
813 		r->name = "BIOS";
814 		return;
815 	}
816 #endif
817 
818 	/* Default unless a driver reloads it */
819 	r->name = "default";
820 	r->get = NULL;
821 	r->set = NULL;
822 
823 	DBG(KERN_DEBUG "PCI: Attempting to find IRQ router for %04x:%04x\n",
824 	    rt->rtr_vendor, rt->rtr_device);
825 
826 	pirq_router_dev = pci_get_bus_and_slot(rt->rtr_bus, rt->rtr_devfn);
827 	if (!pirq_router_dev) {
828 		DBG(KERN_DEBUG "PCI: Interrupt router not found at "
829 			"%02x:%02x\n", rt->rtr_bus, rt->rtr_devfn);
830 		return;
831 	}
832 
833 	for( h = pirq_routers; h->vendor; h++) {
834 		/* First look for a router match */
835 		if (rt->rtr_vendor == h->vendor && h->probe(r, pirq_router_dev, rt->rtr_device))
836 			break;
837 		/* Fall back to a device match */
838 		if (pirq_router_dev->vendor == h->vendor && h->probe(r, pirq_router_dev, pirq_router_dev->device))
839 			break;
840 	}
841 	printk(KERN_INFO "PCI: Using IRQ router %s [%04x/%04x] at %s\n",
842 		pirq_router.name,
843 		pirq_router_dev->vendor,
844 		pirq_router_dev->device,
845 		pci_name(pirq_router_dev));
846 
847 	/* The device remains referenced for the kernel lifetime */
848 }
849 
850 static struct irq_info *pirq_get_info(struct pci_dev *dev)
851 {
852 	struct irq_routing_table *rt = pirq_table;
853 	int entries = (rt->size - sizeof(struct irq_routing_table)) / sizeof(struct irq_info);
854 	struct irq_info *info;
855 
856 	for (info = rt->slots; entries--; info++)
857 		if (info->bus == dev->bus->number && PCI_SLOT(info->devfn) == PCI_SLOT(dev->devfn))
858 			return info;
859 	return NULL;
860 }
861 
862 static int pcibios_lookup_irq(struct pci_dev *dev, int assign)
863 {
864 	u8 pin;
865 	struct irq_info *info;
866 	int i, pirq, newirq;
867 	int irq = 0;
868 	u32 mask;
869 	struct irq_router *r = &pirq_router;
870 	struct pci_dev *dev2 = NULL;
871 	char *msg = NULL;
872 
873 	/* Find IRQ pin */
874 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
875 	if (!pin) {
876 		DBG(KERN_DEBUG " -> no interrupt pin\n");
877 		return 0;
878 	}
879 	pin = pin - 1;
880 
881 	/* Find IRQ routing entry */
882 
883 	if (!pirq_table)
884 		return 0;
885 
886 	DBG(KERN_DEBUG "IRQ for %s[%c]", pci_name(dev), 'A' + pin);
887 	info = pirq_get_info(dev);
888 	if (!info) {
889 		DBG(" -> not found in routing table\n" KERN_DEBUG);
890 		return 0;
891 	}
892 	pirq = info->irq[pin].link;
893 	mask = info->irq[pin].bitmap;
894 	if (!pirq) {
895 		DBG(" -> not routed\n" KERN_DEBUG);
896 		return 0;
897 	}
898 	DBG(" -> PIRQ %02x, mask %04x, excl %04x", pirq, mask, pirq_table->exclusive_irqs);
899 	mask &= pcibios_irq_mask;
900 
901 	/* Work around broken HP Pavilion Notebooks which assign USB to
902 	   IRQ 9 even though it is actually wired to IRQ 11 */
903 
904 	if (broken_hp_bios_irq9 && pirq == 0x59 && dev->irq == 9) {
905 		dev->irq = 11;
906 		pci_write_config_byte(dev, PCI_INTERRUPT_LINE, 11);
907 		r->set(pirq_router_dev, dev, pirq, 11);
908 	}
909 
910 	/* same for Acer Travelmate 360, but with CB and irq 11 -> 10 */
911 	if (acer_tm360_irqrouting && dev->irq == 11 && dev->vendor == PCI_VENDOR_ID_O2) {
912 		pirq = 0x68;
913 		mask = 0x400;
914 		dev->irq = r->get(pirq_router_dev, dev, pirq);
915 		pci_write_config_byte(dev, PCI_INTERRUPT_LINE, dev->irq);
916 	}
917 
918 	/*
919 	 * Find the best IRQ to assign: use the one
920 	 * reported by the device if possible.
921 	 */
922 	newirq = dev->irq;
923 	if (newirq && !((1 << newirq) & mask)) {
924 		if ( pci_probe & PCI_USE_PIRQ_MASK) newirq = 0;
925 		else printk("\n" KERN_WARNING
926 			"PCI: IRQ %i for device %s doesn't match PIRQ mask "
927 			"- try pci=usepirqmask\n" KERN_DEBUG, newirq,
928 			pci_name(dev));
929 	}
930 	if (!newirq && assign) {
931 		for (i = 0; i < 16; i++) {
932 			if (!(mask & (1 << i)))
933 				continue;
934 			if (pirq_penalty[i] < pirq_penalty[newirq] && can_request_irq(i, IRQF_SHARED))
935 				newirq = i;
936 		}
937 	}
938 	DBG(" -> newirq=%d", newirq);
939 
940 	/* Check if it is hardcoded */
941 	if ((pirq & 0xf0) == 0xf0) {
942 		irq = pirq & 0xf;
943 		DBG(" -> hardcoded IRQ %d\n", irq);
944 		msg = "Hardcoded";
945 	} else if ( r->get && (irq = r->get(pirq_router_dev, dev, pirq)) && \
946 	((!(pci_probe & PCI_USE_PIRQ_MASK)) || ((1 << irq) & mask)) ) {
947 		DBG(" -> got IRQ %d\n", irq);
948 		msg = "Found";
949 		eisa_set_level_irq(irq);
950 	} else if (newirq && r->set && (dev->class >> 8) != PCI_CLASS_DISPLAY_VGA) {
951 		DBG(" -> assigning IRQ %d", newirq);
952 		if (r->set(pirq_router_dev, dev, pirq, newirq)) {
953 			eisa_set_level_irq(newirq);
954 			DBG(" ... OK\n");
955 			msg = "Assigned";
956 			irq = newirq;
957 		}
958 	}
959 
960 	if (!irq) {
961 		DBG(" ... failed\n");
962 		if (newirq && mask == (1 << newirq)) {
963 			msg = "Guessed";
964 			irq = newirq;
965 		} else
966 			return 0;
967 	}
968 	printk(KERN_INFO "PCI: %s IRQ %d for device %s\n", msg, irq, pci_name(dev));
969 
970 	/* Update IRQ for all devices with the same pirq value */
971 	while ((dev2 = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev2)) != NULL) {
972 		pci_read_config_byte(dev2, PCI_INTERRUPT_PIN, &pin);
973 		if (!pin)
974 			continue;
975 		pin--;
976 		info = pirq_get_info(dev2);
977 		if (!info)
978 			continue;
979 		if (info->irq[pin].link == pirq) {
980 			/* We refuse to override the dev->irq information. Give a warning! */
981 		    	if ( dev2->irq && dev2->irq != irq && \
982 			(!(pci_probe & PCI_USE_PIRQ_MASK) || \
983 			((1 << dev2->irq) & mask)) ) {
984 #ifndef CONFIG_PCI_MSI
985 		    		printk(KERN_INFO "IRQ routing conflict for %s, have irq %d, want irq %d\n",
986 				       pci_name(dev2), dev2->irq, irq);
987 #endif
988 		    		continue;
989 		    	}
990 			dev2->irq = irq;
991 			pirq_penalty[irq]++;
992 			if (dev != dev2)
993 				printk(KERN_INFO "PCI: Sharing IRQ %d with %s\n", irq, pci_name(dev2));
994 		}
995 	}
996 	return 1;
997 }
998 
999 static void __init pcibios_fixup_irqs(void)
1000 {
1001 	struct pci_dev *dev = NULL;
1002 	u8 pin;
1003 
1004 	DBG(KERN_DEBUG "PCI: IRQ fixup\n");
1005 	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
1006 		/*
1007 		 * If the BIOS has set an out of range IRQ number, just ignore it.
1008 		 * Also keep track of which IRQ's are already in use.
1009 		 */
1010 		if (dev->irq >= 16) {
1011 			DBG(KERN_DEBUG "%s: ignoring bogus IRQ %d\n", pci_name(dev), dev->irq);
1012 			dev->irq = 0;
1013 		}
1014 		/* If the IRQ is already assigned to a PCI device, ignore its ISA use penalty */
1015 		if (pirq_penalty[dev->irq] >= 100 && pirq_penalty[dev->irq] < 100000)
1016 			pirq_penalty[dev->irq] = 0;
1017 		pirq_penalty[dev->irq]++;
1018 	}
1019 
1020 	dev = NULL;
1021 	while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
1022 		pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
1023 #ifdef CONFIG_X86_IO_APIC
1024 		/*
1025 		 * Recalculate IRQ numbers if we use the I/O APIC.
1026 		 */
1027 		if (io_apic_assign_pci_irqs)
1028 		{
1029 			int irq;
1030 
1031 			if (pin) {
1032 				pin--;		/* interrupt pins are numbered starting from 1 */
1033 				irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin);
1034 	/*
1035 	 * Busses behind bridges are typically not listed in the MP-table.
1036 	 * In this case we have to look up the IRQ based on the parent bus,
1037 	 * parent slot, and pin number. The SMP code detects such bridged
1038 	 * busses itself so we should get into this branch reliably.
1039 	 */
1040 				if (irq < 0 && dev->bus->parent) { /* go back to the bridge */
1041 					struct pci_dev * bridge = dev->bus->self;
1042 
1043 					pin = (pin + PCI_SLOT(dev->devfn)) % 4;
1044 					irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number,
1045 							PCI_SLOT(bridge->devfn), pin);
1046 					if (irq >= 0)
1047 						printk(KERN_WARNING "PCI: using PPB %s[%c] to get irq %d\n",
1048 							pci_name(bridge), 'A' + pin, irq);
1049 				}
1050 				if (irq >= 0) {
1051 					printk(KERN_INFO "PCI->APIC IRQ transform: %s[%c] -> IRQ %d\n",
1052 						pci_name(dev), 'A' + pin, irq);
1053 					dev->irq = irq;
1054 				}
1055 			}
1056 		}
1057 #endif
1058 		/*
1059 		 * Still no IRQ? Try to lookup one...
1060 		 */
1061 		if (pin && !dev->irq)
1062 			pcibios_lookup_irq(dev, 0);
1063 	}
1064 }
1065 
1066 /*
1067  * Work around broken HP Pavilion Notebooks which assign USB to
1068  * IRQ 9 even though it is actually wired to IRQ 11
1069  */
1070 static int __init fix_broken_hp_bios_irq9(const struct dmi_system_id *d)
1071 {
1072 	if (!broken_hp_bios_irq9) {
1073 		broken_hp_bios_irq9 = 1;
1074 		printk(KERN_INFO "%s detected - fixing broken IRQ routing\n", d->ident);
1075 	}
1076 	return 0;
1077 }
1078 
1079 /*
1080  * Work around broken Acer TravelMate 360 Notebooks which assign
1081  * Cardbus to IRQ 11 even though it is actually wired to IRQ 10
1082  */
1083 static int __init fix_acer_tm360_irqrouting(const struct dmi_system_id *d)
1084 {
1085 	if (!acer_tm360_irqrouting) {
1086 		acer_tm360_irqrouting = 1;
1087 		printk(KERN_INFO "%s detected - fixing broken IRQ routing\n", d->ident);
1088 	}
1089 	return 0;
1090 }
1091 
1092 static struct dmi_system_id __initdata pciirq_dmi_table[] = {
1093 	{
1094 		.callback = fix_broken_hp_bios_irq9,
1095 		.ident = "HP Pavilion N5400 Series Laptop",
1096 		.matches = {
1097 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
1098 			DMI_MATCH(DMI_BIOS_VERSION, "GE.M1.03"),
1099 			DMI_MATCH(DMI_PRODUCT_VERSION, "HP Pavilion Notebook Model GE"),
1100 			DMI_MATCH(DMI_BOARD_VERSION, "OmniBook N32N-736"),
1101 		},
1102 	},
1103 	{
1104 		.callback = fix_acer_tm360_irqrouting,
1105 		.ident = "Acer TravelMate 36x Laptop",
1106 		.matches = {
1107 			DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
1108 			DMI_MATCH(DMI_PRODUCT_NAME, "TravelMate 360"),
1109 		},
1110 	},
1111 	{ }
1112 };
1113 
1114 static int __init pcibios_irq_init(void)
1115 {
1116 	DBG(KERN_DEBUG "PCI: IRQ init\n");
1117 
1118 	if (pcibios_enable_irq || raw_pci_ops == NULL)
1119 		return 0;
1120 
1121 	dmi_check_system(pciirq_dmi_table);
1122 
1123 	pirq_table = pirq_find_routing_table();
1124 
1125 #ifdef CONFIG_PCI_BIOS
1126 	if (!pirq_table && (pci_probe & PCI_BIOS_IRQ_SCAN))
1127 		pirq_table = pcibios_get_irq_routing_table();
1128 #endif
1129 	if (pirq_table) {
1130 		pirq_peer_trick();
1131 		pirq_find_router(&pirq_router);
1132 		if (pirq_table->exclusive_irqs) {
1133 			int i;
1134 			for (i=0; i<16; i++)
1135 				if (!(pirq_table->exclusive_irqs & (1 << i)))
1136 					pirq_penalty[i] += 100;
1137 		}
1138 		/* If we're using the I/O APIC, avoid using the PCI IRQ routing table */
1139 		if (io_apic_assign_pci_irqs)
1140 			pirq_table = NULL;
1141 	}
1142 
1143 	pcibios_enable_irq = pirq_enable_irq;
1144 
1145 	pcibios_fixup_irqs();
1146 	return 0;
1147 }
1148 
1149 subsys_initcall(pcibios_irq_init);
1150 
1151 
1152 static void pirq_penalize_isa_irq(int irq, int active)
1153 {
1154 	/*
1155 	 *  If any ISAPnP device reports an IRQ in its list of possible
1156 	 *  IRQ's, we try to avoid assigning it to PCI devices.
1157 	 */
1158 	if (irq < 16) {
1159 		if (active)
1160 			pirq_penalty[irq] += 1000;
1161 		else
1162 			pirq_penalty[irq] += 100;
1163 	}
1164 }
1165 
1166 void pcibios_penalize_isa_irq(int irq, int active)
1167 {
1168 #ifdef CONFIG_ACPI
1169 	if (!acpi_noirq)
1170 		acpi_penalize_isa_irq(irq, active);
1171 	else
1172 #endif
1173 		pirq_penalize_isa_irq(irq, active);
1174 }
1175 
1176 static int pirq_enable_irq(struct pci_dev *dev)
1177 {
1178 	u8 pin;
1179 	struct pci_dev *temp_dev;
1180 
1181 	pci_read_config_byte(dev, PCI_INTERRUPT_PIN, &pin);
1182 	if (pin && !pcibios_lookup_irq(dev, 1) && !dev->irq) {
1183 		char *msg = "";
1184 
1185 		pin--;		/* interrupt pins are numbered starting from 1 */
1186 
1187 		if (io_apic_assign_pci_irqs) {
1188 			int irq;
1189 
1190 			irq = IO_APIC_get_PCI_irq_vector(dev->bus->number, PCI_SLOT(dev->devfn), pin);
1191 			/*
1192 			 * Busses behind bridges are typically not listed in the MP-table.
1193 			 * In this case we have to look up the IRQ based on the parent bus,
1194 			 * parent slot, and pin number. The SMP code detects such bridged
1195 			 * busses itself so we should get into this branch reliably.
1196 			 */
1197 			temp_dev = dev;
1198 			while (irq < 0 && dev->bus->parent) { /* go back to the bridge */
1199 				struct pci_dev * bridge = dev->bus->self;
1200 
1201 				pin = (pin + PCI_SLOT(dev->devfn)) % 4;
1202 				irq = IO_APIC_get_PCI_irq_vector(bridge->bus->number,
1203 						PCI_SLOT(bridge->devfn), pin);
1204 				if (irq >= 0)
1205 					printk(KERN_WARNING "PCI: using PPB %s[%c] to get irq %d\n",
1206 						pci_name(bridge), 'A' + pin, irq);
1207 				dev = bridge;
1208 			}
1209 			dev = temp_dev;
1210 			if (irq >= 0) {
1211 				printk(KERN_INFO "PCI->APIC IRQ transform: %s[%c] -> IRQ %d\n",
1212 					pci_name(dev), 'A' + pin, irq);
1213 				dev->irq = irq;
1214 				return 0;
1215 			} else
1216 				msg = " Probably buggy MP table.";
1217 		} else if (pci_probe & PCI_BIOS_IRQ_SCAN)
1218 			msg = "";
1219 		else
1220 			msg = " Please try using pci=biosirq.";
1221 
1222 		/* With IDE legacy devices the IRQ lookup failure is not a problem.. */
1223 		if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE && !(dev->class & 0x5))
1224 			return 0;
1225 
1226 		printk(KERN_WARNING "PCI: No IRQ known for interrupt pin %c of device %s.%s\n",
1227 		       'A' + pin, pci_name(dev), msg);
1228 	}
1229 	return 0;
1230 }
1231