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
26struct 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
33static 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 */
43static 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 */
55static 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 */
67static 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
79struct 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 */
96static 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
108static 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
136static 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
199static 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
237extern int noioapicquirk;
238extern int noioapicreroute;
239
240static 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 */
260static 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
291static 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)
342static 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
360static inline int acpi_isa_register_gsi(struct pci_dev *dev)
361{
362	return -ENODEV;
363}
364#endif
365
366static 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
383int 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
477void 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