xref: /freebsd/sys/dev/pci/vga_pci.c (revision a466cc55373fc3cf86837f09da729535b57e69a1)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2005 John Baldwin <jhb@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 /*
32  * Simple driver for PCI VGA display devices.  Drivers such as agp(4) and
33  * drm(4) should attach as children of this device.
34  *
35  * XXX: The vgapci name is a hack until we somehow merge the isa vga driver
36  * in or rename it.
37  */
38 
39 #include <sys/param.h>
40 #include <sys/bus.h>
41 #include <sys/kernel.h>
42 #include <sys/module.h>
43 #include <sys/rman.h>
44 #include <sys/sysctl.h>
45 #include <sys/systm.h>
46 
47 #if defined(__amd64__) || defined(__i386__)
48 #include <vm/vm.h>
49 #include <vm/pmap.h>
50 #endif
51 
52 #include <dev/pci/pcireg.h>
53 #include <dev/pci/pcivar.h>
54 
55 #include <compat/x86bios/x86bios.h> /* To re-POST the card. */
56 
57 struct vga_resource {
58 	struct resource	*vr_res;
59 	int	vr_refs;
60 };
61 
62 struct vga_pci_softc {
63 	device_t	vga_msi_child;	/* Child driver using MSI. */
64 	struct vga_resource vga_bars[PCIR_MAX_BAR_0 + 1];
65 	struct vga_resource vga_bios;
66 };
67 
68 SYSCTL_DECL(_hw_pci);
69 
70 static struct vga_resource *lookup_res(struct vga_pci_softc *sc, int rid);
71 static struct resource *vga_pci_alloc_resource(device_t dev, device_t child,
72     int type, int *rid, rman_res_t start, rman_res_t end, rman_res_t count,
73     u_int flags);
74 static int	vga_pci_release_resource(device_t dev, device_t child, int type,
75     int rid, struct resource *r);
76 
77 int vga_pci_default_unit = -1;
78 SYSCTL_INT(_hw_pci, OID_AUTO, default_vgapci_unit, CTLFLAG_RDTUN,
79     &vga_pci_default_unit, -1, "Default VGA-compatible display");
80 
81 int
82 vga_pci_is_boot_display(device_t dev)
83 {
84 	int unit;
85 	device_t pcib;
86 	uint16_t config;
87 
88 	/* Check that the given device is a video card */
89 	if ((pci_get_class(dev) != PCIC_DISPLAY &&
90 	    (pci_get_class(dev) != PCIC_OLD ||
91 	     pci_get_subclass(dev) != PCIS_OLD_VGA)))
92 		return (0);
93 
94 	unit = device_get_unit(dev);
95 
96 	if (vga_pci_default_unit >= 0) {
97 		/*
98 		 * The boot display device was determined by a previous
99 		 * call to this function, or the user forced it using
100 		 * the hw.pci.default_vgapci_unit tunable.
101 		 */
102 		return (vga_pci_default_unit == unit);
103 	}
104 
105 	/*
106 	 * The primary video card used as a boot display must have the
107 	 * "I/O" and "Memory Address Space Decoding" bits set in its
108 	 * Command register.
109 	 *
110 	 * Furthermore, if the card is attached to a bridge, instead of
111 	 * the root PCI bus, the bridge must have the "VGA Enable" bit
112 	 * set in its Control register.
113 	 */
114 
115 	pcib = device_get_parent(device_get_parent(dev));
116 	if (device_get_devclass(device_get_parent(pcib)) ==
117 	    devclass_find("pci")) {
118 		/*
119 		 * The parent bridge is a PCI-to-PCI bridge: check the
120 		 * value of the "VGA Enable" bit.
121 		 */
122 		config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
123 		if ((config & PCIB_BCR_VGA_ENABLE) == 0)
124 			return (0);
125 	}
126 
127 	config = pci_read_config(dev, PCIR_COMMAND, 2);
128 	if ((config & (PCIM_CMD_PORTEN | PCIM_CMD_MEMEN)) == 0)
129 		return (0);
130 
131 	/*
132 	 * Disable interrupts until a chipset driver is loaded for
133 	 * this PCI device. Else unhandled display adapter interrupts
134 	 * might freeze the CPU.
135 	 */
136 	pci_write_config(dev, PCIR_COMMAND, config | PCIM_CMD_INTxDIS, 2);
137 
138 	/* This video card is the boot display: record its unit number. */
139 	vga_pci_default_unit = unit;
140 	device_set_flags(dev, 1);
141 
142 	return (1);
143 }
144 
145 static void
146 vga_pci_reset(device_t dev)
147 {
148 	int ps;
149 	/*
150 	 * FLR is unsupported on GPUs so attempt a power-management reset by cycling
151 	 * the device in/out of D3 state.
152 	 * PCI spec says we can only go into D3 state from D0 state.
153 	 * Transition from D[12] into D0 before going to D3 state.
154 	 */
155 	ps = pci_get_powerstate(dev);
156 	if (ps != PCI_POWERSTATE_D0 && ps != PCI_POWERSTATE_D3)
157 		pci_set_powerstate(dev, PCI_POWERSTATE_D0);
158 	if (pci_get_powerstate(dev) != PCI_POWERSTATE_D3)
159 		pci_set_powerstate(dev, PCI_POWERSTATE_D3);
160 	pci_set_powerstate(dev, ps);
161 }
162 
163 void *
164 vga_pci_map_bios(device_t dev, size_t *size)
165 {
166 	struct vga_resource *vr;
167 	struct resource *res;
168 	device_t pcib;
169 	uint32_t rom_addr;
170 	uint16_t config;
171 	volatile unsigned char *bios;
172 	int i, rid, found;
173 
174 #if defined(__amd64__) || defined(__i386__)
175 	if (vga_pci_is_boot_display(dev)) {
176 		/*
177 		 * On x86, the System BIOS copy the default display
178 		 * device's Video BIOS at a fixed location in system
179 		 * memory (0xC0000, 128 kBytes long) at boot time.
180 		 *
181 		 * We use this copy for the default boot device, because
182 		 * the original ROM may not be valid after boot.
183 		 */
184 
185 		*size = VGA_PCI_BIOS_SHADOW_SIZE;
186 		return (pmap_mapbios(VGA_PCI_BIOS_SHADOW_ADDR, *size));
187 	}
188 #endif
189 
190 	pcib = device_get_parent(device_get_parent(dev));
191 	if (device_get_devclass(device_get_parent(pcib)) ==
192 	    devclass_find("pci")) {
193 		/*
194 		 * The parent bridge is a PCI-to-PCI bridge: check the
195 		 * value of the "VGA Enable" bit.
196 		 */
197 		config = pci_read_config(pcib, PCIR_BRIDGECTL_1, 2);
198 		if ((config & PCIB_BCR_VGA_ENABLE) == 0) {
199 			config |= PCIB_BCR_VGA_ENABLE;
200 			pci_write_config(pcib, PCIR_BRIDGECTL_1, config, 2);
201 		}
202 	}
203 
204 	switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
205 	case PCIM_HDRTYPE_BRIDGE:
206 		rid = PCIR_BIOS_1;
207 		break;
208 	case PCIM_HDRTYPE_CARDBUS:
209 		rid = 0;
210 		break;
211 	default:
212 		rid = PCIR_BIOS;
213 		break;
214 	}
215 	if (rid == 0)
216 		return (NULL);
217 	res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
218 	    ~0, 1, RF_ACTIVE);
219 
220 	if (res == NULL) {
221 		device_printf(dev, "vga_pci_alloc_resource failed\n");
222 		return (NULL);
223 	}
224 	bios = rman_get_virtual(res);
225 	*size = rman_get_size(res);
226 	for (found = i = 0; i < hz; i++) {
227 		found = (bios[0] == 0x55 && bios[1] == 0xaa);
228 		if (found)
229 			break;
230 		pause("vgabios", 1);
231 	}
232 	if (found)
233 		return (__DEVOLATILE(void *, bios));
234 	if (bootverbose)
235 		device_printf(dev, "initial ROM mapping failed -- resetting\n");
236 
237 	/*
238 	 * Enable ROM decode
239 	 */
240 	vga_pci_reset(dev);
241 	rom_addr = pci_read_config(dev, rid, 4);
242 	rom_addr &= 0x7ff;
243 	rom_addr |= rman_get_start(res) | 0x1;
244 	pci_write_config(dev, rid, rom_addr, 4);
245 	vr = lookup_res(device_get_softc(dev), rid);
246 	vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
247 	    vr->vr_res);
248 
249 	/*
250 	 * re-allocate
251 	 */
252 	res = vga_pci_alloc_resource(dev, NULL, SYS_RES_MEMORY, &rid, 0,
253 	    ~0, 1, RF_ACTIVE);
254 	if (res == NULL) {
255 		device_printf(dev, "vga_pci_alloc_resource failed\n");
256 		return (NULL);
257 	}
258 	bios = rman_get_virtual(res);
259 	*size = rman_get_size(res);
260 	for (found = i = 0; i < 3*hz; i++) {
261 		found = (bios[0] == 0x55 && bios[1] == 0xaa);
262 		if (found)
263 			break;
264 		pause("vgabios", 1);
265 	}
266 	if (found)
267 		return (__DEVOLATILE(void *, bios));
268 	device_printf(dev, "ROM mapping failed\n");
269 	vr = lookup_res(device_get_softc(dev), rid);
270 	vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
271 	    vr->vr_res);
272 	return (NULL);
273 }
274 
275 void
276 vga_pci_unmap_bios(device_t dev, void *bios)
277 {
278 	struct vga_resource *vr;
279 	int rid;
280 
281 	if (bios == NULL) {
282 		return;
283 	}
284 
285 #if defined(__amd64__) || defined(__i386__)
286 	if (vga_pci_is_boot_display(dev)) {
287 		/* We mapped the BIOS shadow copy located at 0xC0000. */
288 		pmap_unmapdev(bios, VGA_PCI_BIOS_SHADOW_SIZE);
289 
290 		return;
291 	}
292 #endif
293 	switch(pci_read_config(dev, PCIR_HDRTYPE, 1)) {
294 	case PCIM_HDRTYPE_BRIDGE:
295 		rid = PCIR_BIOS_1;
296 		break;
297 	case PCIM_HDRTYPE_CARDBUS:
298 		rid = 0;
299 		break;
300 	default:
301 		rid = PCIR_BIOS;
302 		break;
303 	}
304 	if (rid == 0)
305 		return;
306 	/*
307 	 * Look up the PCIR_BIOS resource in our softc.  It should match
308 	 * the address we returned previously.
309 	 */
310 	vr = lookup_res(device_get_softc(dev), rid);
311 	KASSERT(vr->vr_res != NULL, ("vga_pci_unmap_bios: bios not mapped"));
312 	KASSERT(rman_get_virtual(vr->vr_res) == bios,
313 	    ("vga_pci_unmap_bios: mismatch"));
314 	vga_pci_release_resource(dev, NULL, SYS_RES_MEMORY, rid,
315 	    vr->vr_res);
316 }
317 
318 int
319 vga_pci_repost(device_t dev)
320 {
321 #if defined(__amd64__) || defined(__i386__)
322 	x86regs_t regs;
323 
324 	if (!vga_pci_is_boot_display(dev))
325 		return (EINVAL);
326 
327 	if (x86bios_get_orm(VGA_PCI_BIOS_SHADOW_ADDR) == NULL)
328 		return (ENOTSUP);
329 
330 	x86bios_init_regs(&regs);
331 
332 	regs.R_AH = pci_get_bus(dev);
333 	regs.R_AL = (pci_get_slot(dev) << 3) | (pci_get_function(dev) & 0x07);
334 	regs.R_DL = 0x80;
335 
336 	device_printf(dev, "REPOSTing\n");
337 	x86bios_call(&regs, X86BIOS_PHYSTOSEG(VGA_PCI_BIOS_SHADOW_ADDR + 3),
338 	    X86BIOS_PHYSTOOFF(VGA_PCI_BIOS_SHADOW_ADDR + 3));
339 
340 	x86bios_get_intr(0x10);
341 
342 	return (0);
343 #else
344 	return (ENOTSUP);
345 #endif
346 }
347 
348 static int
349 vga_pci_probe(device_t dev)
350 {
351 
352 	switch (pci_get_class(dev)) {
353 	case PCIC_DISPLAY:
354 		break;
355 	case PCIC_OLD:
356 		if (pci_get_subclass(dev) != PCIS_OLD_VGA)
357 			return (ENXIO);
358 		break;
359 	default:
360 		return (ENXIO);
361 	}
362 
363 	/* Probe default display. */
364 	vga_pci_is_boot_display(dev);
365 
366 	device_set_desc(dev, "VGA-compatible display");
367 	return (BUS_PROBE_GENERIC);
368 }
369 
370 static int
371 vga_pci_attach(device_t dev)
372 {
373 
374 	bus_generic_probe(dev);
375 
376 	/* Always create a drm child for now to make it easier on drm. */
377 	device_add_child(dev, "drm", -1);
378 	device_add_child(dev, "drmn", -1);
379 	bus_generic_attach(dev);
380 
381 	if (vga_pci_is_boot_display(dev))
382 		device_printf(dev, "Boot video device\n");
383 
384 	return (0);
385 }
386 
387 static int
388 vga_pci_suspend(device_t dev)
389 {
390 
391 	return (bus_generic_suspend(dev));
392 }
393 
394 static int
395 vga_pci_detach(device_t dev)
396 {
397 	int error;
398 
399 	error = bus_generic_detach(dev);
400 	if (error == 0)
401 		error = device_delete_children(dev);
402 	return (error);
403 }
404 
405 static int
406 vga_pci_resume(device_t dev)
407 {
408 
409 	return (bus_generic_resume(dev));
410 }
411 
412 /* Bus interface. */
413 
414 static int
415 vga_pci_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
416 {
417 
418 	return (BUS_READ_IVAR(device_get_parent(dev), dev, which, result));
419 }
420 
421 static int
422 vga_pci_write_ivar(device_t dev, device_t child, int which, uintptr_t value)
423 {
424 
425 	return (EINVAL);
426 }
427 
428 static int
429 vga_pci_setup_intr(device_t dev, device_t child, struct resource *irq,
430     int flags, driver_filter_t *filter, driver_intr_t *intr, void *arg,
431     void **cookiep)
432 {
433 	return (BUS_SETUP_INTR(device_get_parent(dev), dev, irq, flags,
434 	    filter, intr, arg, cookiep));
435 }
436 
437 static int
438 vga_pci_teardown_intr(device_t dev, device_t child, struct resource *irq,
439     void *cookie)
440 {
441 	return (BUS_TEARDOWN_INTR(device_get_parent(dev), dev, irq, cookie));
442 }
443 
444 static struct vga_resource *
445 lookup_res(struct vga_pci_softc *sc, int rid)
446 {
447 	int bar;
448 
449 	if (rid == PCIR_BIOS)
450 		return (&sc->vga_bios);
451 	bar = PCI_RID2BAR(rid);
452 	if (bar >= 0 && bar <= PCIR_MAX_BAR_0)
453 		return (&sc->vga_bars[bar]);
454 	return (NULL);
455 }
456 
457 static struct resource *
458 vga_pci_alloc_resource(device_t dev, device_t child, int type, int *rid,
459     rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
460 {
461 	struct vga_resource *vr;
462 
463 	switch (type) {
464 	case SYS_RES_MEMORY:
465 	case SYS_RES_IOPORT:
466 		/*
467 		 * For BARs, we cache the resource so that we only allocate it
468 		 * from the PCI bus once.
469 		 */
470 		vr = lookup_res(device_get_softc(dev), *rid);
471 		if (vr == NULL)
472 			return (NULL);
473 		if (vr->vr_res == NULL)
474 			vr->vr_res = bus_alloc_resource(dev, type, rid, start,
475 			    end, count, flags);
476 		if (vr->vr_res != NULL)
477 			vr->vr_refs++;
478 		return (vr->vr_res);
479 	}
480 	return (bus_alloc_resource(dev, type, rid, start, end, count, flags));
481 }
482 
483 static int
484 vga_pci_release_resource(device_t dev, device_t child, int type, int rid,
485     struct resource *r)
486 {
487 	struct vga_resource *vr;
488 	int error;
489 
490 	switch (type) {
491 	case SYS_RES_MEMORY:
492 	case SYS_RES_IOPORT:
493 		/*
494 		 * For BARs, we release the resource from the PCI bus
495 		 * when the last child reference goes away.
496 		 */
497 		vr = lookup_res(device_get_softc(dev), rid);
498 		if (vr == NULL)
499 			return (EINVAL);
500 		if (vr->vr_res == NULL)
501 			return (EINVAL);
502 		KASSERT(vr->vr_res == r, ("vga_pci resource mismatch"));
503 		if (vr->vr_refs > 1) {
504 			vr->vr_refs--;
505 			return (0);
506 		}
507 		KASSERT(vr->vr_refs > 0,
508 		    ("vga_pci resource reference count underflow"));
509 		error = bus_release_resource(dev, type, rid, r);
510 		if (error == 0) {
511 			vr->vr_res = NULL;
512 			vr->vr_refs = 0;
513 		}
514 		return (error);
515 	}
516 
517 	return (bus_release_resource(dev, type, rid, r));
518 }
519 
520 /* PCI interface. */
521 
522 static uint32_t
523 vga_pci_read_config(device_t dev, device_t child, int reg, int width)
524 {
525 
526 	return (pci_read_config(dev, reg, width));
527 }
528 
529 static void
530 vga_pci_write_config(device_t dev, device_t child, int reg,
531     uint32_t val, int width)
532 {
533 
534 	pci_write_config(dev, reg, val, width);
535 }
536 
537 static int
538 vga_pci_enable_busmaster(device_t dev, device_t child)
539 {
540 
541 	return (pci_enable_busmaster(dev));
542 }
543 
544 static int
545 vga_pci_disable_busmaster(device_t dev, device_t child)
546 {
547 
548 	return (pci_disable_busmaster(dev));
549 }
550 
551 static int
552 vga_pci_enable_io(device_t dev, device_t child, int space)
553 {
554 
555 	device_printf(dev, "child %s requested pci_enable_io\n",
556 	    device_get_nameunit(child));
557 	return (pci_enable_io(dev, space));
558 }
559 
560 static int
561 vga_pci_disable_io(device_t dev, device_t child, int space)
562 {
563 
564 	device_printf(dev, "child %s requested pci_disable_io\n",
565 	    device_get_nameunit(child));
566 	return (pci_disable_io(dev, space));
567 }
568 
569 static int
570 vga_pci_get_vpd_ident(device_t dev, device_t child, const char **identptr)
571 {
572 
573 	return (pci_get_vpd_ident(dev, identptr));
574 }
575 
576 static int
577 vga_pci_get_vpd_readonly(device_t dev, device_t child, const char *kw,
578     const char **vptr)
579 {
580 
581 	return (pci_get_vpd_readonly(dev, kw, vptr));
582 }
583 
584 static int
585 vga_pci_set_powerstate(device_t dev, device_t child, int state)
586 {
587 
588 	device_printf(dev, "child %s requested pci_set_powerstate\n",
589 	    device_get_nameunit(child));
590 	return (pci_set_powerstate(dev, state));
591 }
592 
593 static int
594 vga_pci_get_powerstate(device_t dev, device_t child)
595 {
596 
597 	device_printf(dev, "child %s requested pci_get_powerstate\n",
598 	    device_get_nameunit(child));
599 	return (pci_get_powerstate(dev));
600 }
601 
602 static int
603 vga_pci_assign_interrupt(device_t dev, device_t child)
604 {
605 
606 	device_printf(dev, "child %s requested pci_assign_interrupt\n",
607 	    device_get_nameunit(child));
608 	return (PCI_ASSIGN_INTERRUPT(device_get_parent(dev), dev));
609 }
610 
611 static int
612 vga_pci_find_cap(device_t dev, device_t child, int capability,
613     int *capreg)
614 {
615 
616 	return (pci_find_cap(dev, capability, capreg));
617 }
618 
619 static int
620 vga_pci_find_next_cap(device_t dev, device_t child, int capability,
621     int start, int *capreg)
622 {
623 
624 	return (pci_find_next_cap(dev, capability, start, capreg));
625 }
626 
627 static int
628 vga_pci_find_extcap(device_t dev, device_t child, int capability,
629     int *capreg)
630 {
631 
632 	return (pci_find_extcap(dev, capability, capreg));
633 }
634 
635 static int
636 vga_pci_find_next_extcap(device_t dev, device_t child, int capability,
637     int start, int *capreg)
638 {
639 
640 	return (pci_find_next_extcap(dev, capability, start, capreg));
641 }
642 
643 static int
644 vga_pci_find_htcap(device_t dev, device_t child, int capability,
645     int *capreg)
646 {
647 
648 	return (pci_find_htcap(dev, capability, capreg));
649 }
650 
651 static int
652 vga_pci_find_next_htcap(device_t dev, device_t child, int capability,
653     int start, int *capreg)
654 {
655 
656 	return (pci_find_next_htcap(dev, capability, start, capreg));
657 }
658 
659 static int
660 vga_pci_alloc_msi(device_t dev, device_t child, int *count)
661 {
662 	struct vga_pci_softc *sc;
663 	int error;
664 
665 	sc = device_get_softc(dev);
666 	if (sc->vga_msi_child != NULL)
667 		return (EBUSY);
668 	error = pci_alloc_msi(dev, count);
669 	if (error == 0)
670 		sc->vga_msi_child = child;
671 	return (error);
672 }
673 
674 static int
675 vga_pci_alloc_msix(device_t dev, device_t child, int *count)
676 {
677 	struct vga_pci_softc *sc;
678 	int error;
679 
680 	sc = device_get_softc(dev);
681 	if (sc->vga_msi_child != NULL)
682 		return (EBUSY);
683 	error = pci_alloc_msix(dev, count);
684 	if (error == 0)
685 		sc->vga_msi_child = child;
686 	return (error);
687 }
688 
689 static int
690 vga_pci_remap_msix(device_t dev, device_t child, int count,
691     const u_int *vectors)
692 {
693 	struct vga_pci_softc *sc;
694 
695 	sc = device_get_softc(dev);
696 	if (sc->vga_msi_child != child)
697 		return (ENXIO);
698 	return (pci_remap_msix(dev, count, vectors));
699 }
700 
701 static int
702 vga_pci_release_msi(device_t dev, device_t child)
703 {
704 	struct vga_pci_softc *sc;
705 	int error;
706 
707 	sc = device_get_softc(dev);
708 	if (sc->vga_msi_child != child)
709 		return (ENXIO);
710 	error = pci_release_msi(dev);
711 	if (error == 0)
712 		sc->vga_msi_child = NULL;
713 	return (error);
714 }
715 
716 static int
717 vga_pci_msi_count(device_t dev, device_t child)
718 {
719 
720 	return (pci_msi_count(dev));
721 }
722 
723 static int
724 vga_pci_msix_count(device_t dev, device_t child)
725 {
726 
727 	return (pci_msix_count(dev));
728 }
729 
730 static bus_dma_tag_t
731 vga_pci_get_dma_tag(device_t bus, device_t child)
732 {
733 
734 	return (bus_get_dma_tag(bus));
735 }
736 
737 static device_method_t vga_pci_methods[] = {
738 	/* Device interface */
739 	DEVMETHOD(device_probe,		vga_pci_probe),
740 	DEVMETHOD(device_attach,	vga_pci_attach),
741 	DEVMETHOD(device_shutdown,	bus_generic_shutdown),
742 	DEVMETHOD(device_suspend,	vga_pci_suspend),
743 	DEVMETHOD(device_detach,	vga_pci_detach),
744 	DEVMETHOD(device_resume,	vga_pci_resume),
745 
746 	/* Bus interface */
747 	DEVMETHOD(bus_read_ivar,	vga_pci_read_ivar),
748 	DEVMETHOD(bus_write_ivar,	vga_pci_write_ivar),
749 	DEVMETHOD(bus_setup_intr,	vga_pci_setup_intr),
750 	DEVMETHOD(bus_teardown_intr,	vga_pci_teardown_intr),
751 	DEVMETHOD(bus_alloc_resource,	vga_pci_alloc_resource),
752 	DEVMETHOD(bus_release_resource,	vga_pci_release_resource),
753 	DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
754 	DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
755 	DEVMETHOD(bus_get_dma_tag,	vga_pci_get_dma_tag),
756 
757 	/* PCI interface */
758 	DEVMETHOD(pci_read_config,	vga_pci_read_config),
759 	DEVMETHOD(pci_write_config,	vga_pci_write_config),
760 	DEVMETHOD(pci_enable_busmaster,	vga_pci_enable_busmaster),
761 	DEVMETHOD(pci_disable_busmaster, vga_pci_disable_busmaster),
762 	DEVMETHOD(pci_enable_io,	vga_pci_enable_io),
763 	DEVMETHOD(pci_disable_io,	vga_pci_disable_io),
764 	DEVMETHOD(pci_get_vpd_ident,	vga_pci_get_vpd_ident),
765 	DEVMETHOD(pci_get_vpd_readonly,	vga_pci_get_vpd_readonly),
766 	DEVMETHOD(pci_get_powerstate,	vga_pci_get_powerstate),
767 	DEVMETHOD(pci_set_powerstate,	vga_pci_set_powerstate),
768 	DEVMETHOD(pci_assign_interrupt,	vga_pci_assign_interrupt),
769 	DEVMETHOD(pci_find_cap,		vga_pci_find_cap),
770 	DEVMETHOD(pci_find_next_cap,	vga_pci_find_next_cap),
771 	DEVMETHOD(pci_find_extcap,	vga_pci_find_extcap),
772 	DEVMETHOD(pci_find_next_extcap,	vga_pci_find_next_extcap),
773 	DEVMETHOD(pci_find_htcap,	vga_pci_find_htcap),
774 	DEVMETHOD(pci_find_next_htcap,	vga_pci_find_next_htcap),
775 	DEVMETHOD(pci_alloc_msi,	vga_pci_alloc_msi),
776 	DEVMETHOD(pci_alloc_msix,	vga_pci_alloc_msix),
777 	DEVMETHOD(pci_remap_msix,	vga_pci_remap_msix),
778 	DEVMETHOD(pci_release_msi,	vga_pci_release_msi),
779 	DEVMETHOD(pci_msi_count,	vga_pci_msi_count),
780 	DEVMETHOD(pci_msix_count,	vga_pci_msix_count),
781 	{ 0, 0 }
782 };
783 
784 static driver_t vga_pci_driver = {
785 	"vgapci",
786 	vga_pci_methods,
787 	sizeof(struct vga_pci_softc),
788 };
789 
790 DRIVER_MODULE(vgapci, pci, vga_pci_driver, 0, 0);
791 MODULE_DEPEND(vgapci, x86bios, 1, 1, 1);
792