1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  pci_irq.c - ACPI PCI Interrupt Routing ($Revision: 11 $)
4  *
5  *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
6  *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
7  *  Copyright (C) 2002       Dominik Brodowski <devel@brodo.de>
8  *  (c) Copyright 2008 Hewlett-Packard Development Company, L.P.
9  *	Bjorn Helgaas <bjorn.helgaas@hp.com>
10  */
11 
12 #define pr_fmt(fmt) "ACPI: PCI: " fmt
13 
14 #include <linux/dmi.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/types.h>
19 #include <linux/spinlock.h>
20 #include <linux/pm.h>
21 #include <linux/pci.h>
22 #include <linux/acpi.h>
23 #include <linux/slab.h>
24 #include <linux/interrupt.h>
25 
26 struct acpi_prt_entry {
27 	struct acpi_pci_id	id;
28 	u8			pin;
29 	acpi_handle		link;
30 	u32			index;		/* GSI, or link _CRS index */
31 };
32 
pin_name(int pin)33 static inline char pin_name(int pin)
34 {
35 	return 'A' + pin - 1;
36 }
37 
38 /* --------------------------------------------------------------------------
39                          PCI IRQ Routing Table (PRT) Support
40    -------------------------------------------------------------------------- */
41 
42 /* http://bugzilla.kernel.org/show_bug.cgi?id=4773 */
43 static const struct dmi_system_id medion_md9580[] = {
44 	{
45 		.ident = "Medion MD9580-F laptop",
46 		.matches = {
47 			DMI_MATCH(DMI_SYS_VENDOR, "MEDIONNB"),
48 			DMI_MATCH(DMI_PRODUCT_NAME, "A555"),
49 		},
50 	},
51 	{ }
52 };
53 
54 /* http://bugzilla.kernel.org/show_bug.cgi?id=5044 */
55 static const struct dmi_system_id dell_optiplex[] = {
56 	{
57 		.ident = "Dell Optiplex GX1",
58 		.matches = {
59 			DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
60 			DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex GX1 600S+"),
61 		},
62 	},
63 	{ }
64 };
65 
66 /* http://bugzilla.kernel.org/show_bug.cgi?id=10138 */
67 static const struct dmi_system_id hp_t5710[] = {
68 	{
69 		.ident = "HP t5710",
70 		.matches = {
71 			DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
72 			DMI_MATCH(DMI_PRODUCT_NAME, "hp t5000 series"),
73 			DMI_MATCH(DMI_BOARD_NAME, "098Ch"),
74 		},
75 	},
76 	{ }
77 };
78 
79 struct prt_quirk {
80 	const struct dmi_system_id *system;
81 	unsigned int		segment;
82 	unsigned int		bus;
83 	unsigned int		device;
84 	unsigned char		pin;
85 	const char		*source;	/* according to BIOS */
86 	const char		*actual_source;
87 };
88 
89 #define PCI_INTX_PIN(c)		(c - 'A' + 1)
90 
91 /*
92  * These systems have incorrect _PRT entries.  The BIOS claims the PCI
93  * interrupt at the listed segment/bus/device/pin is connected to the first
94  * link device, but it is actually connected to the second.
95  */
96 static const struct prt_quirk prt_quirks[] = {
97 	{ medion_md9580, 0, 0, 9, PCI_INTX_PIN('A'),
98 		"\\_SB_.PCI0.ISA_.LNKA",
99 		"\\_SB_.PCI0.ISA_.LNKB"},
100 	{ dell_optiplex, 0, 0, 0xd, PCI_INTX_PIN('A'),
101 		"\\_SB_.LNKB",
102 		"\\_SB_.LNKA"},
103 	{ hp_t5710, 0, 0, 1, PCI_INTX_PIN('A'),
104 		"\\_SB_.PCI0.LNK1",
105 		"\\_SB_.PCI0.LNK3"},
106 };
107 
do_prt_fixups(struct acpi_prt_entry * entry,struct acpi_pci_routing_table * prt)108 static void do_prt_fixups(struct acpi_prt_entry *entry,
109 			  struct acpi_pci_routing_table *prt)
110 {
111 	int i;
112 	const struct prt_quirk *quirk;
113 
114 	for (i = 0; i < ARRAY_SIZE(prt_quirks); i++) {
115 		quirk = &prt_quirks[i];
116 
117 		/* All current quirks involve link devices, not GSIs */
118 		if (dmi_check_system(quirk->system) &&
119 		    entry->id.segment == quirk->segment &&
120 		    entry->id.bus == quirk->bus &&
121 		    entry->id.device == quirk->device &&
122 		    entry->pin == quirk->pin &&
123 		    !strcmp(prt->source, quirk->source) &&
124 		    strlen(prt->source) >= strlen(quirk->actual_source)) {
125 			pr_warn("Firmware reports "
126 				"%04x:%02x:%02x PCI INT %c connected to %s; "
127 				"changing to %s\n",
128 				entry->id.segment, entry->id.bus,
129 				entry->id.device, pin_name(entry->pin),
130 				prt->source, quirk->actual_source);
131 			strcpy(prt->source, quirk->actual_source);
132 		}
133 	}
134 }
135 
acpi_pci_irq_check_entry(acpi_handle handle,struct pci_dev * dev,int pin,struct acpi_pci_routing_table * prt,struct acpi_prt_entry ** entry_ptr)136 static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev,
137 				  int pin, struct acpi_pci_routing_table *prt,
138 				  struct acpi_prt_entry **entry_ptr)
139 {
140 	int segment = pci_domain_nr(dev->bus);
141 	int bus = dev->bus->number;
142 	int device = pci_ari_enabled(dev->bus) ? 0 : PCI_SLOT(dev->devfn);
143 	struct acpi_prt_entry *entry;
144 
145 	if (((prt->address >> 16) & 0xffff) != device ||
146 	    prt->pin + 1 != pin)
147 		return -ENODEV;
148 
149 	entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
150 	if (!entry)
151 		return -ENOMEM;
152 
153 	/*
154 	 * Note that the _PRT uses 0=INTA, 1=INTB, etc, while PCI uses
155 	 * 1=INTA, 2=INTB.  We use the PCI encoding throughout, so convert
156 	 * it here.
157 	 */
158 	entry->id.segment = segment;
159 	entry->id.bus = bus;
160 	entry->id.device = (prt->address >> 16) & 0xFFFF;
161 	entry->pin = prt->pin + 1;
162 
163 	do_prt_fixups(entry, prt);
164 
165 	entry->index = prt->source_index;
166 
167 	/*
168 	 * Type 1: Dynamic
169 	 * ---------------
170 	 * The 'source' field specifies the PCI interrupt link device used to
171 	 * configure the IRQ assigned to this slot|dev|pin.  The 'source_index'
172 	 * indicates which resource descriptor in the resource template (of
173 	 * the link device) this interrupt is allocated from.
174 	 *
175 	 * NOTE: Don't query the Link Device for IRQ information at this time
176 	 *       because Link Device enumeration may not have occurred yet
177 	 *       (e.g. exists somewhere 'below' this _PRT entry in the ACPI
178 	 *       namespace).
179 	 */
180 	if (prt->source[0])
181 		acpi_get_handle(handle, prt->source, &entry->link);
182 
183 	/*
184 	 * Type 2: Static
185 	 * --------------
186 	 * The 'source' field is NULL, and the 'source_index' field specifies
187 	 * the IRQ value, which is hardwired to specific interrupt inputs on
188 	 * the interrupt controller.
189 	 */
190 	pr_debug("%04x:%02x:%02x[%c] -> %s[%d]\n",
191 		 entry->id.segment, entry->id.bus, entry->id.device,
192 		 pin_name(entry->pin), prt->source, entry->index);
193 
194 	*entry_ptr = entry;
195 
196 	return 0;
197 }
198 
acpi_pci_irq_find_prt_entry(struct pci_dev * dev,int pin,struct acpi_prt_entry ** entry_ptr)199 static int acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
200 			  int pin, struct acpi_prt_entry **entry_ptr)
201 {
202 	acpi_status status;
203 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
204 	struct acpi_pci_routing_table *entry;
205 	acpi_handle handle = NULL;
206 
207 	if (dev->bus->bridge)
208 		handle = ACPI_HANDLE(dev->bus->bridge);
209 
210 	if (!handle)
211 		return -ENODEV;
212 
213 	/* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
214 	status = acpi_get_irq_routing_table(handle, &buffer);
215 	if (ACPI_FAILURE(status)) {
216 		kfree(buffer.pointer);
217 		return -ENODEV;
218 	}
219 
220 	entry = buffer.pointer;
221 	while (entry && (entry->length > 0)) {
222 		if (!acpi_pci_irq_check_entry(handle, dev, pin,
223 						 entry, entry_ptr))
224 			break;
225 		entry = (struct acpi_pci_routing_table *)
226 		    ((unsigned long)entry + entry->length);
227 	}
228 
229 	kfree(buffer.pointer);
230 	return 0;
231 }
232 
233 /* --------------------------------------------------------------------------
234                           PCI Interrupt Routing Support
235    -------------------------------------------------------------------------- */
236 #ifdef CONFIG_X86_IO_APIC
237 extern int noioapicquirk;
238 extern int noioapicreroute;
239 
bridge_has_boot_interrupt_variant(struct pci_bus * bus)240 static int bridge_has_boot_interrupt_variant(struct pci_bus *bus)
241 {
242 	struct pci_bus *bus_it;
243 
244 	for (bus_it = bus ; bus_it ; bus_it = bus_it->parent) {
245 		if (!bus_it->self)
246 			return 0;
247 		if (bus_it->self->irq_reroute_variant)
248 			return bus_it->self->irq_reroute_variant;
249 	}
250 	return 0;
251 }
252 
253 /*
254  * Some chipsets (e.g. Intel 6700PXH) generate a legacy INTx when the IRQ
255  * entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel does
256  * during interrupt handling). When this INTx generation cannot be disabled,
257  * we reroute these interrupts to their legacy equivalent to get rid of
258  * spurious interrupts.
259  */
acpi_reroute_boot_interrupt(struct pci_dev * dev,struct acpi_prt_entry * entry)260 static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
261 				       struct acpi_prt_entry *entry)
262 {
263 	if (noioapicquirk || noioapicreroute) {
264 		return 0;
265 	} else {
266 		switch (bridge_has_boot_interrupt_variant(dev->bus)) {
267 		case 0:
268 			/* no rerouting necessary */
269 			return 0;
270 		case INTEL_IRQ_REROUTE_VARIANT:
271 			/*
272 			 * Remap according to INTx routing table in 6700PXH
273 			 * specs, intel order number 302628-002, section
274 			 * 2.15.2. Other chipsets (80332, ...) have the same
275 			 * mapping and are handled here as well.
276 			 */
277 			dev_info(&dev->dev, "PCI IRQ %d -> rerouted to legacy "
278 				 "IRQ %d\n", entry->index,
279 				 (entry->index % 4) + 16);
280 			entry->index = (entry->index % 4) + 16;
281 			return 1;
282 		default:
283 			dev_warn(&dev->dev, "Cannot reroute IRQ %d to legacy "
284 				 "IRQ: unknown mapping\n", entry->index);
285 			return -1;
286 		}
287 	}
288 }
289 #endif /* CONFIG_X86_IO_APIC */
290 
acpi_pci_irq_lookup(struct pci_dev * dev,int pin)291 static struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
292 {
293 	struct acpi_prt_entry *entry = NULL;
294 	struct pci_dev *bridge;
295 	u8 bridge_pin, orig_pin = pin;
296 	int ret;
297 
298 	ret = acpi_pci_irq_find_prt_entry(dev, pin, &entry);
299 	if (!ret && entry) {
300 #ifdef CONFIG_X86_IO_APIC
301 		acpi_reroute_boot_interrupt(dev, entry);
302 #endif /* CONFIG_X86_IO_APIC */
303 		dev_dbg(&dev->dev, "Found [%c] _PRT entry\n", pin_name(pin));
304 		return entry;
305 	}
306 
307 	/*
308 	 * Attempt to derive an IRQ for this device from a parent bridge's
309 	 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
310 	 */
311 	bridge = dev->bus->self;
312 	while (bridge) {
313 		pin = pci_swizzle_interrupt_pin(dev, pin);
314 
315 		if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
316 			/* PC card has the same IRQ as its cardbridge */
317 			bridge_pin = bridge->pin;
318 			if (!bridge_pin) {
319 				dev_dbg(&bridge->dev, "No interrupt pin configured\n");
320 				return NULL;
321 			}
322 			pin = bridge_pin;
323 		}
324 
325 		ret = acpi_pci_irq_find_prt_entry(bridge, pin, &entry);
326 		if (!ret && entry) {
327 			dev_dbg(&dev->dev, "Derived GSI INT %c from %s\n",
328 				pin_name(orig_pin), pci_name(bridge));
329 			return entry;
330 		}
331 
332 		dev = bridge;
333 		bridge = dev->bus->self;
334 	}
335 
336 	dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",
337 		 pin_name(orig_pin));
338 	return NULL;
339 }
340 
341 #if IS_ENABLED(CONFIG_ISA) || IS_ENABLED(CONFIG_EISA)
acpi_isa_register_gsi(struct pci_dev * dev)342 static int acpi_isa_register_gsi(struct pci_dev *dev)
343 {
344 	u32 dev_gsi;
345 
346 	/* Interrupt Line values above 0xF are forbidden */
347 	if (dev->irq > 0 && (dev->irq <= 0xF) &&
348 	    acpi_isa_irq_available(dev->irq) &&
349 	    (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) {
350 		dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d\n",
351 			 pin_name(dev->pin), dev->irq);
352 		acpi_register_gsi(&dev->dev, dev_gsi,
353 				  ACPI_LEVEL_SENSITIVE,
354 				  ACPI_ACTIVE_LOW);
355 		return 0;
356 	}
357 	return -EINVAL;
358 }
359 #else
acpi_isa_register_gsi(struct pci_dev * dev)360 static inline int acpi_isa_register_gsi(struct pci_dev *dev)
361 {
362 	return -ENODEV;
363 }
364 #endif
365 
acpi_pci_irq_valid(struct pci_dev * dev,u8 pin)366 static inline bool acpi_pci_irq_valid(struct pci_dev *dev, u8 pin)
367 {
368 #ifdef CONFIG_X86
369 	/*
370 	 * On x86 irq line 0xff means "unknown" or "no connection"
371 	 * (PCI 3.0, Section 6.2.4, footnote on page 223).
372 	 */
373 	if (dev->irq == 0xff) {
374 		dev->irq = IRQ_NOTCONNECTED;
375 		dev_warn(&dev->dev, "PCI INT %c: not connected\n",
376 			 pin_name(pin));
377 		return false;
378 	}
379 #endif
380 	return true;
381 }
382 
acpi_pci_irq_enable(struct pci_dev * dev)383 int acpi_pci_irq_enable(struct pci_dev *dev)
384 {
385 	struct acpi_prt_entry *entry;
386 	int gsi;
387 	u8 pin;
388 	int triggering = ACPI_LEVEL_SENSITIVE;
389 	/*
390 	 * On ARM systems with the GIC interrupt model, or LoongArch
391 	 * systems with the LPIC interrupt model, level interrupts
392 	 * are always polarity high by specification; PCI legacy
393 	 * IRQs lines are inverted before reaching the interrupt
394 	 * controller and must therefore be considered active high
395 	 * as default.
396 	 */
397 	int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ||
398 		       acpi_irq_model == ACPI_IRQ_MODEL_LPIC ?
399 				      ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
400 	char *link = NULL;
401 	char link_desc[16];
402 	int rc;
403 
404 	pin = dev->pin;
405 	if (!pin) {
406 		dev_dbg(&dev->dev, "No interrupt pin configured\n");
407 		return 0;
408 	}
409 
410 	if (dev->irq_managed && dev->irq > 0)
411 		return 0;
412 
413 	entry = acpi_pci_irq_lookup(dev, pin);
414 	if (!entry) {
415 		/*
416 		 * IDE legacy mode controller IRQs are magic. Why do compat
417 		 * extensions always make such a nasty mess.
418 		 */
419 		if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&
420 				(dev->class & 0x05) == 0)
421 			return 0;
422 	}
423 
424 	if (entry) {
425 		if (entry->link)
426 			gsi = acpi_pci_link_allocate_irq(entry->link,
427 							 entry->index,
428 							 &triggering, &polarity,
429 							 &link);
430 		else
431 			gsi = entry->index;
432 	} else
433 		gsi = -1;
434 
435 	if (gsi < 0) {
436 		/*
437 		 * No IRQ known to the ACPI subsystem - maybe the BIOS /
438 		 * driver reported one, then use it. Exit in any case.
439 		 */
440 		if (!acpi_pci_irq_valid(dev, pin)) {
441 			kfree(entry);
442 			return 0;
443 		}
444 
445 		if (acpi_isa_register_gsi(dev))
446 			dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
447 				 pin_name(pin));
448 
449 		kfree(entry);
450 		return 0;
451 	}
452 
453 	rc = acpi_register_gsi(&dev->dev, gsi, triggering, polarity);
454 	if (rc < 0) {
455 		dev_warn(&dev->dev, "PCI INT %c: failed to register GSI\n",
456 			 pin_name(pin));
457 		kfree(entry);
458 		return rc;
459 	}
460 	dev->irq = rc;
461 	dev->irq_managed = 1;
462 
463 	if (link)
464 		snprintf(link_desc, sizeof(link_desc), " -> Link[%s]", link);
465 	else
466 		link_desc[0] = '\0';
467 
468 	dev_dbg(&dev->dev, "PCI INT %c%s -> GSI %u (%s, %s) -> IRQ %d\n",
469 		pin_name(pin), link_desc, gsi,
470 		(triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
471 		(polarity == ACPI_ACTIVE_LOW) ? "low" : "high", dev->irq);
472 
473 	kfree(entry);
474 	return 0;
475 }
476 
acpi_pci_irq_disable(struct pci_dev * dev)477 void acpi_pci_irq_disable(struct pci_dev *dev)
478 {
479 	struct acpi_prt_entry *entry;
480 	int gsi;
481 	u8 pin;
482 
483 	pin = dev->pin;
484 	if (!pin || !dev->irq_managed || dev->irq <= 0)
485 		return;
486 
487 	/* Keep IOAPIC pin configuration when suspending */
488 	if (dev->dev.power.is_prepared)
489 		return;
490 #ifdef	CONFIG_PM
491 	if (dev->dev.power.runtime_status == RPM_SUSPENDING)
492 		return;
493 #endif
494 
495 	entry = acpi_pci_irq_lookup(dev, pin);
496 	if (!entry)
497 		return;
498 
499 	if (entry->link)
500 		gsi = acpi_pci_link_free_irq(entry->link);
501 	else
502 		gsi = entry->index;
503 
504 	kfree(entry);
505 
506 	/*
507 	 * TBD: It might be worth clearing dev->irq by magic constant
508 	 * (e.g. PCI_UNDEFINED_IRQ).
509 	 */
510 
511 	dev_dbg(&dev->dev, "PCI INT %c disabled\n", pin_name(pin));
512 	if (gsi >= 0) {
513 		acpi_unregister_gsi(gsi);
514 		dev->irq_managed = 0;
515 	}
516 }
517