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#include <linux/string_choices.h>
26
27struct acpi_prt_entry {
28 struct acpi_pci_id id;
29 u8 pin;
30 acpi_handle link;
31 u32 index; /* GSI, or link _CRS index */
32};
33
34static inline char pin_name(int pin)
35{
36 return 'A' + pin - 1;
37}
38
39/* --------------------------------------------------------------------------
40 PCI IRQ Routing Table (PRT) Support
41 -------------------------------------------------------------------------- */
42
43/* http://bugzilla.kernel.org/show_bug.cgi?id=4773 */
44static const struct dmi_system_id medion_md9580[] = {
45 {
46 .ident = "Medion MD9580-F laptop",
47 .matches = {
48 DMI_MATCH(DMI_SYS_VENDOR, "MEDIONNB"),
49 DMI_MATCH(DMI_PRODUCT_NAME, "A555"),
50 },
51 },
52 { }
53};
54
55/* http://bugzilla.kernel.org/show_bug.cgi?id=5044 */
56static const struct dmi_system_id dell_optiplex[] = {
57 {
58 .ident = "Dell Optiplex GX1",
59 .matches = {
60 DMI_MATCH(DMI_SYS_VENDOR, "Dell Computer Corporation"),
61 DMI_MATCH(DMI_PRODUCT_NAME, "OptiPlex GX1 600S+"),
62 },
63 },
64 { }
65};
66
67/* http://bugzilla.kernel.org/show_bug.cgi?id=10138 */
68static const struct dmi_system_id hp_t5710[] = {
69 {
70 .ident = "HP t5710",
71 .matches = {
72 DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
73 DMI_MATCH(DMI_PRODUCT_NAME, "hp t5000 series"),
74 DMI_MATCH(DMI_BOARD_NAME, "098Ch"),
75 },
76 },
77 { }
78};
79
80struct prt_quirk {
81 const struct dmi_system_id *system;
82 unsigned int segment;
83 unsigned int bus;
84 unsigned int device;
85 unsigned char pin;
86 const char *source; /* according to BIOS */
87 const char *actual_source;
88};
89
90#define PCI_INTX_PIN(c) (c - 'A' + 1)
91
92/*
93 * These systems have incorrect _PRT entries. The BIOS claims the PCI
94 * interrupt at the listed segment/bus/device/pin is connected to the first
95 * link device, but it is actually connected to the second.
96 */
97static const struct prt_quirk prt_quirks[] = {
98 { medion_md9580, 0, 0, 9, PCI_INTX_PIN('A'),
99 "\\_SB_.PCI0.ISA_.LNKA",
100 "\\_SB_.PCI0.ISA_.LNKB"},
101 { dell_optiplex, 0, 0, 0xd, PCI_INTX_PIN('A'),
102 "\\_SB_.LNKB",
103 "\\_SB_.LNKA"},
104 { hp_t5710, 0, 0, 1, PCI_INTX_PIN('A'),
105 "\\_SB_.PCI0.LNK1",
106 "\\_SB_.PCI0.LNK3"},
107};
108
109static void do_prt_fixups(struct acpi_prt_entry *entry,
110 struct acpi_pci_routing_table *prt)
111{
112 int i;
113 const struct prt_quirk *quirk;
114
115 for (i = 0; i < ARRAY_SIZE(prt_quirks); i++) {
116 quirk = &prt_quirks[i];
117
118 /* All current quirks involve link devices, not GSIs */
119 if (dmi_check_system(list: quirk->system) &&
120 entry->id.segment == quirk->segment &&
121 entry->id.bus == quirk->bus &&
122 entry->id.device == quirk->device &&
123 entry->pin == quirk->pin &&
124 !strcmp(prt->source, quirk->source) &&
125 strlen(prt->source) >= strlen(quirk->actual_source)) {
126 pr_warn("Firmware reports "
127 "%04x:%02x:%02x PCI INT %c connected to %s; "
128 "changing to %s\n",
129 entry->id.segment, entry->id.bus,
130 entry->id.device, pin_name(entry->pin),
131 prt->source, quirk->actual_source);
132 strcpy(prt->source, quirk->actual_source);
133 }
134 }
135}
136
137static int acpi_pci_irq_check_entry(acpi_handle handle, struct pci_dev *dev,
138 int pin, struct acpi_pci_routing_table *prt,
139 struct acpi_prt_entry **entry_ptr)
140{
141 int segment = pci_domain_nr(bus: dev->bus);
142 int bus = dev->bus->number;
143 int device = pci_ari_enabled(bus: dev->bus) ? 0 : PCI_SLOT(dev->devfn);
144 struct acpi_prt_entry *entry;
145
146 if (((prt->address >> 16) & 0xffff) != device ||
147 prt->pin + 1 != pin)
148 return -ENODEV;
149
150 entry = kzalloc(sizeof(struct acpi_prt_entry), GFP_KERNEL);
151 if (!entry)
152 return -ENOMEM;
153
154 /*
155 * Note that the _PRT uses 0=INTA, 1=INTB, etc, while PCI uses
156 * 1=INTA, 2=INTB. We use the PCI encoding throughout, so convert
157 * it here.
158 */
159 entry->id.segment = segment;
160 entry->id.bus = bus;
161 entry->id.device = (prt->address >> 16) & 0xFFFF;
162 entry->pin = prt->pin + 1;
163
164 do_prt_fixups(entry, prt);
165
166 entry->index = prt->source_index;
167
168 /*
169 * Type 1: Dynamic
170 * ---------------
171 * The 'source' field specifies the PCI interrupt link device used to
172 * configure the IRQ assigned to this slot|dev|pin. The 'source_index'
173 * indicates which resource descriptor in the resource template (of
174 * the link device) this interrupt is allocated from.
175 *
176 * NOTE: Don't query the Link Device for IRQ information at this time
177 * because Link Device enumeration may not have occurred yet
178 * (e.g. exists somewhere 'below' this _PRT entry in the ACPI
179 * namespace).
180 */
181 if (prt->source[0])
182 acpi_get_handle(parent: handle, pathname: prt->source, ret_handle: &entry->link);
183
184 /*
185 * Type 2: Static
186 * --------------
187 * The 'source' field is NULL, and the 'source_index' field specifies
188 * the IRQ value, which is hardwired to specific interrupt inputs on
189 * the interrupt controller.
190 */
191 pr_debug("%04x:%02x:%02x[%c] -> %s[%d]\n",
192 entry->id.segment, entry->id.bus, entry->id.device,
193 pin_name(entry->pin), prt->source, entry->index);
194
195 *entry_ptr = entry;
196
197 return 0;
198}
199
200static int acpi_pci_irq_find_prt_entry(struct pci_dev *dev,
201 int pin, struct acpi_prt_entry **entry_ptr)
202{
203 acpi_status status;
204 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
205 struct acpi_pci_routing_table *entry;
206 acpi_handle handle = NULL;
207
208 if (dev->bus->bridge)
209 handle = ACPI_HANDLE(dev->bus->bridge);
210
211 if (!handle)
212 return -ENODEV;
213
214 /* 'handle' is the _PRT's parent (root bridge or PCI-PCI bridge) */
215 status = acpi_get_irq_routing_table(device: handle, ret_buffer: &buffer);
216 if (ACPI_FAILURE(status)) {
217 kfree(objp: buffer.pointer);
218 return -ENODEV;
219 }
220
221 entry = buffer.pointer;
222 while (entry && (entry->length > 0)) {
223 if (!acpi_pci_irq_check_entry(handle, dev, pin,
224 prt: entry, entry_ptr))
225 break;
226 entry = (struct acpi_pci_routing_table *)
227 ((unsigned long)entry + entry->length);
228 }
229
230 kfree(objp: buffer.pointer);
231 return 0;
232}
233
234/* --------------------------------------------------------------------------
235 PCI Interrupt Routing Support
236 -------------------------------------------------------------------------- */
237#ifdef CONFIG_X86_IO_APIC
238extern int noioapicquirk;
239extern int noioapicreroute;
240
241static int bridge_has_boot_interrupt_variant(struct pci_bus *bus)
242{
243 struct pci_bus *bus_it;
244
245 for (bus_it = bus ; bus_it ; bus_it = bus_it->parent) {
246 if (!bus_it->self)
247 return 0;
248 if (bus_it->self->irq_reroute_variant)
249 return bus_it->self->irq_reroute_variant;
250 }
251 return 0;
252}
253
254/*
255 * Some chipsets (e.g. Intel 6700PXH) generate a legacy INTx when the IRQ
256 * entry in the chipset's IO-APIC is masked (as, e.g. the RT kernel does
257 * during interrupt handling). When this INTx generation cannot be disabled,
258 * we reroute these interrupts to their legacy equivalent to get rid of
259 * spurious interrupts.
260 */
261static int acpi_reroute_boot_interrupt(struct pci_dev *dev,
262 struct acpi_prt_entry *entry)
263{
264 if (noioapicquirk || noioapicreroute) {
265 return 0;
266 } else {
267 switch (bridge_has_boot_interrupt_variant(bus: dev->bus)) {
268 case 0:
269 /* no rerouting necessary */
270 return 0;
271 case INTEL_IRQ_REROUTE_VARIANT:
272 /*
273 * Remap according to INTx routing table in 6700PXH
274 * specs, intel order number 302628-002, section
275 * 2.15.2. Other chipsets (80332, ...) have the same
276 * mapping and are handled here as well.
277 */
278 dev_info(&dev->dev, "PCI IRQ %d -> rerouted to legacy "
279 "IRQ %d\n", entry->index,
280 (entry->index % 4) + 16);
281 entry->index = (entry->index % 4) + 16;
282 return 1;
283 default:
284 dev_warn(&dev->dev, "Cannot reroute IRQ %d to legacy "
285 "IRQ: unknown mapping\n", entry->index);
286 return -1;
287 }
288 }
289}
290#endif /* CONFIG_X86_IO_APIC */
291
292struct acpi_prt_entry *acpi_pci_irq_lookup(struct pci_dev *dev, int pin)
293{
294 struct acpi_prt_entry *entry = NULL;
295 struct pci_dev *bridge;
296 u8 bridge_pin, orig_pin = pin;
297 int ret;
298
299 ret = acpi_pci_irq_find_prt_entry(dev, pin, entry_ptr: &entry);
300 if (!ret && entry) {
301#ifdef CONFIG_X86_IO_APIC
302 acpi_reroute_boot_interrupt(dev, entry);
303#endif /* CONFIG_X86_IO_APIC */
304 dev_dbg(&dev->dev, "Found [%c] _PRT entry\n", pin_name(pin));
305 return entry;
306 }
307
308 /*
309 * Attempt to derive an IRQ for this device from a parent bridge's
310 * PCI interrupt routing entry (eg. yenta bridge and add-in card bridge).
311 */
312 bridge = dev->bus->self;
313 while (bridge) {
314 pin = pci_swizzle_interrupt_pin(dev, pin);
315
316 if ((bridge->class >> 8) == PCI_CLASS_BRIDGE_CARDBUS) {
317 /* PC card has the same IRQ as its cardbridge */
318 bridge_pin = bridge->pin;
319 if (!bridge_pin) {
320 dev_dbg(&bridge->dev, "No interrupt pin configured\n");
321 return NULL;
322 }
323 pin = bridge_pin;
324 }
325
326 ret = acpi_pci_irq_find_prt_entry(dev: bridge, pin, entry_ptr: &entry);
327 if (!ret && entry) {
328 dev_dbg(&dev->dev, "Derived GSI INT %c from %s\n",
329 pin_name(orig_pin), pci_name(bridge));
330 return entry;
331 }
332
333 dev = bridge;
334 bridge = dev->bus->self;
335 }
336
337 dev_warn(&dev->dev, "can't derive routing for PCI INT %c\n",
338 pin_name(orig_pin));
339 return NULL;
340}
341
342#if IS_ENABLED(CONFIG_ISA) || IS_ENABLED(CONFIG_EISA)
343static int acpi_isa_register_gsi(struct pci_dev *dev)
344{
345 u32 dev_gsi;
346
347 /* Interrupt Line values above 0xF are forbidden */
348 if (dev->irq > 0 && (dev->irq <= 0xF) &&
349 acpi_isa_irq_available(dev->irq) &&
350 (acpi_isa_irq_to_gsi(dev->irq, &dev_gsi) == 0)) {
351 dev_warn(&dev->dev, "PCI INT %c: no GSI - using ISA IRQ %d\n",
352 pin_name(dev->pin), dev->irq);
353 acpi_register_gsi(&dev->dev, dev_gsi,
354 ACPI_LEVEL_SENSITIVE,
355 ACPI_ACTIVE_LOW);
356 return 0;
357 }
358 return -EINVAL;
359}
360#else
361static inline int acpi_isa_register_gsi(struct pci_dev *dev)
362{
363 return -ENODEV;
364}
365#endif
366
367static inline bool acpi_pci_irq_valid(struct pci_dev *dev, u8 pin)
368{
369#ifdef CONFIG_X86
370 /*
371 * On x86 irq line 0xff means "unknown" or "no connection"
372 * (PCI 3.0, Section 6.2.4, footnote on page 223).
373 */
374 if (dev->irq == 0xff) {
375 dev->irq = IRQ_NOTCONNECTED;
376 dev_warn(&dev->dev, "PCI INT %c: not connected\n",
377 pin_name(pin));
378 return false;
379 }
380#endif
381 return true;
382}
383
384int acpi_pci_irq_enable(struct pci_dev *dev)
385{
386 struct acpi_prt_entry *entry;
387 int gsi;
388 u8 pin;
389 int triggering = ACPI_LEVEL_SENSITIVE;
390 /*
391 * On ARM systems with the GIC interrupt model, or LoongArch
392 * systems with the LPIC interrupt model, level interrupts
393 * are always polarity high by specification; PCI legacy
394 * IRQs lines are inverted before reaching the interrupt
395 * controller and must therefore be considered active high
396 * as default.
397 */
398 int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ||
399 acpi_irq_model == ACPI_IRQ_MODEL_LPIC ?
400 ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
401 char *link = NULL;
402 char link_desc[16];
403 int rc;
404
405 pin = dev->pin;
406 if (!pin) {
407 dev_dbg(&dev->dev, "No interrupt pin configured\n");
408 return 0;
409 }
410
411 if (dev->irq_managed && dev->irq > 0)
412 return 0;
413
414 entry = acpi_pci_irq_lookup(dev, pin);
415 if (!entry) {
416 /*
417 * IDE legacy mode controller IRQs are magic. Why do compat
418 * extensions always make such a nasty mess.
419 */
420 if (dev->class >> 8 == PCI_CLASS_STORAGE_IDE &&
421 (dev->class & 0x05) == 0)
422 return 0;
423 }
424
425 if (entry) {
426 if (entry->link)
427 gsi = acpi_pci_link_allocate_irq(handle: entry->link,
428 index: entry->index,
429 triggering: &triggering, polarity: &polarity,
430 name: &link);
431 else
432 gsi = entry->index;
433 } else
434 gsi = -1;
435
436 if (gsi < 0) {
437 /*
438 * No IRQ known to the ACPI subsystem - maybe the BIOS /
439 * driver reported one, then use it. Exit in any case.
440 */
441 if (!acpi_pci_irq_valid(dev, pin)) {
442 kfree(objp: entry);
443 return 0;
444 }
445
446 if (acpi_isa_register_gsi(dev))
447 dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
448 pin_name(pin));
449
450 kfree(objp: entry);
451 return 0;
452 }
453
454 rc = acpi_register_gsi(dev: &dev->dev, gsi, triggering, polarity);
455 if (rc < 0) {
456 dev_warn(&dev->dev, "PCI INT %c: failed to register GSI\n",
457 pin_name(pin));
458 kfree(objp: entry);
459 return rc;
460 }
461 dev->irq = rc;
462 dev->irq_managed = 1;
463
464 if (link)
465 snprintf(buf: link_desc, size: sizeof(link_desc), fmt: " -> Link[%s]", link);
466 else
467 link_desc[0] = '\0';
468
469 dev_dbg(&dev->dev, "PCI INT %c%s -> GSI %u (%s, %s) -> IRQ %d\n",
470 pin_name(pin), link_desc, gsi,
471 (triggering == ACPI_LEVEL_SENSITIVE) ? "level" : "edge",
472 str_low_high(polarity == ACPI_ACTIVE_LOW), dev->irq);
473
474 kfree(objp: entry);
475 return 0;
476}
477
478void acpi_pci_irq_disable(struct pci_dev *dev)
479{
480 struct acpi_prt_entry *entry;
481 int gsi;
482 u8 pin;
483
484 pin = dev->pin;
485 if (!pin || !dev->irq_managed || dev->irq <= 0)
486 return;
487
488 /* Keep IOAPIC pin configuration when suspending */
489 if (dev->dev.power.is_prepared)
490 return;
491#ifdef CONFIG_PM
492 if (dev->dev.power.runtime_status == RPM_SUSPENDING)
493 return;
494#endif
495
496 entry = acpi_pci_irq_lookup(dev, pin);
497 if (!entry)
498 return;
499
500 if (entry->link)
501 gsi = acpi_pci_link_free_irq(handle: entry->link);
502 else
503 gsi = entry->index;
504
505 kfree(objp: entry);
506
507 /*
508 * TBD: It might be worth clearing dev->irq by magic constant
509 * (e.g. PCI_UNDEFINED_IRQ).
510 */
511
512 dev_dbg(&dev->dev, "PCI INT %c disabled\n", pin_name(pin));
513 if (gsi >= 0) {
514 acpi_unregister_gsi(gsi);
515 dev->irq_managed = 0;
516 }
517}
518