xref: /netbsd-src/sys/dev/pci/agp_amd64.c (revision bdc22b2e01993381dcefeff2bc9b56ca75a4235c)
1 /*-
2  * Copyright (c) 2004, 2005 Jung-uk Kim <jkim@FreeBSD.org>
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24  * SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __KERNEL_RCSID(0, "$NetBSD: agp_amd64.c,v 1.8 2015/04/04 15:08:40 riastradh Exp $");
29 
30 #include <sys/param.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
33 #include <sys/kernel.h>
34 #include <sys/proc.h>
35 #include <sys/conf.h>
36 #include <sys/device.h>
37 #include <sys/agpio.h>
38 
39 #include <dev/pci/pcivar.h>
40 #include <dev/pci/pcireg.h>
41 #include <dev/pci/agpvar.h>
42 #include <dev/pci/agpreg.h>
43 
44 #include <dev/pci/pcidevs.h>
45 
46 #include <sys/bus.h>
47 
48 
49 #define	AMD64_MAX_MCTRL		8
50 
51 /* XXX nForce3 requires secondary AGP bridge at 0:11:0. */
52 #define AGP_AMD64_NVIDIA_PCITAG(pc)	pci_make_tag(pc, 0, 11, 0)
53 /* XXX Some VIA bridge requires secondary AGP bridge at 0:1:0. */
54 #define AGP_AMD64_VIA_PCITAG(pc)	pci_make_tag(pc, 0, 1, 0)
55 
56 
57 static uint32_t agp_amd64_get_aperture(struct agp_softc *);
58 static int agp_amd64_set_aperture(struct agp_softc *, uint32_t);
59 static int agp_amd64_bind_page(struct agp_softc *, off_t, bus_addr_t);
60 static int agp_amd64_unbind_page(struct agp_softc *, off_t);
61 static void agp_amd64_flush_tlb(struct agp_softc *);
62 
63 static void agp_amd64_apbase_fixup(struct agp_softc *);
64 
65 static void agp_amd64_uli_init(struct agp_softc *);
66 static int agp_amd64_uli_set_aperture(struct agp_softc *, uint32_t);
67 
68 static int agp_amd64_nvidia_match(const struct pci_attach_args *, uint16_t);
69 static void agp_amd64_nvidia_init(struct agp_softc *);
70 static int agp_amd64_nvidia_set_aperture(struct agp_softc *, uint32_t);
71 
72 static int agp_amd64_via_match(const struct pci_attach_args *);
73 static void agp_amd64_via_init(struct agp_softc *);
74 static int agp_amd64_via_set_aperture(struct agp_softc *, uint32_t);
75 
76 
77 struct agp_amd64_softc {
78 	uint32_t		initial_aperture;
79 	struct agp_gatt		*gatt;
80 	uint32_t		apbase;
81 	pcitag_t		ctrl_tag;	/* use NVIDIA and VIA */
82 	pcitag_t		mctrl_tag[AMD64_MAX_MCTRL];
83 	int			n_mctrl;
84 	int			via_agp;
85 };
86 
87 static struct agp_methods agp_amd64_methods = {
88 	agp_amd64_get_aperture,
89 	agp_amd64_set_aperture,
90 	agp_amd64_bind_page,
91 	agp_amd64_unbind_page,
92 	agp_amd64_flush_tlb,
93 	agp_generic_enable,
94 	agp_generic_alloc_memory,
95 	agp_generic_free_memory,
96 	agp_generic_bind_memory,
97 	agp_generic_unbind_memory,
98 };
99 
100 
101 int
102 agp_amd64_match(const struct pci_attach_args *pa)
103 {
104 
105 	switch (PCI_VENDOR(pa->pa_id)) {
106 	case PCI_VENDOR_AMD:
107 		switch (PCI_PRODUCT(pa->pa_id)) {
108 		case PCI_PRODUCT_AMD_AGP8151_DEV:
109 			return 1;
110 		}
111 		break;
112 
113 	case PCI_VENDOR_SIS:
114 		switch (PCI_PRODUCT(pa->pa_id)) {
115 		case PCI_PRODUCT_SIS_755:
116 		case PCI_PRODUCT_SIS_760:
117 			return 1;
118 		}
119 		break;
120 
121 	case PCI_VENDOR_ALI:
122 		switch (PCI_PRODUCT(pa->pa_id)) {
123 		case PCI_PRODUCT_ALI_M1689:
124 			return 1;
125 		}
126 		break;
127 
128 	case PCI_VENDOR_NVIDIA:
129 		switch (PCI_PRODUCT(pa->pa_id)) {
130 		case PCI_PRODUCT_NVIDIA_NFORCE3_PCHB:
131 			return agp_amd64_nvidia_match(pa,
132 			    PCI_PRODUCT_NVIDIA_NFORCE3_PPB2);
133 
134 			/* NOTREACHED */
135 
136 		case PCI_PRODUCT_NVIDIA_NFORCE3_250_PCHB:
137 			return agp_amd64_nvidia_match(pa,
138 			    PCI_PRODUCT_NVIDIA_NFORCE3_250_AGP);
139 
140 			/* NOTREACHED */
141 		}
142 		break;
143 
144 	case PCI_VENDOR_VIATECH:
145 		switch (PCI_PRODUCT(pa->pa_id)) {
146 		case PCI_PRODUCT_VIATECH_K8M800_0:
147 		case PCI_PRODUCT_VIATECH_K8T890_0:
148 		case PCI_PRODUCT_VIATECH_K8HTB_0:
149 		case PCI_PRODUCT_VIATECH_K8HTB:
150 			return 1;
151 		}
152 		break;
153 	}
154 
155 	return 0;
156 }
157 
158 static int
159 agp_amd64_nvidia_match(const struct pci_attach_args *pa, uint16_t devid)
160 {
161 	pcitag_t tag;
162 	pcireg_t reg;
163 
164 	tag = AGP_AMD64_NVIDIA_PCITAG(pa->pa_pc);
165 
166 	reg = pci_conf_read(pa->pa_pc, tag, PCI_CLASS_REG);
167 	if (PCI_CLASS(reg) != PCI_CLASS_BRIDGE ||
168 	    PCI_SUBCLASS(reg) != PCI_SUBCLASS_BRIDGE_PCI)
169 		return 0;
170 
171 	reg = pci_conf_read(pa->pa_pc, tag, PCI_ID_REG);
172 	if (PCI_VENDOR(reg) != PCI_VENDOR_NVIDIA || PCI_PRODUCT(reg) != devid)
173 		return 0;
174 
175 	return 1;
176 }
177 
178 static int
179 agp_amd64_via_match(const struct pci_attach_args *pa)
180 {
181 	pcitag_t tag;
182 	pcireg_t reg;
183 
184 	tag = AGP_AMD64_VIA_PCITAG(pa->pa_pc);
185 
186 	reg = pci_conf_read(pa->pa_pc, tag, PCI_CLASS_REG);
187 	if (PCI_CLASS(reg) != PCI_CLASS_BRIDGE ||
188 	    PCI_SUBCLASS(reg) != PCI_SUBCLASS_BRIDGE_PCI)
189 		return 0;
190 
191 	reg = pci_conf_read(pa->pa_pc, tag, PCI_ID_REG);
192 	if (PCI_VENDOR(reg) != PCI_VENDOR_VIATECH ||
193 	    PCI_PRODUCT(reg) != PCI_PRODUCT_VIATECH_K8HTB_AGP)
194 		return 0;
195 
196 	return 1;
197 }
198 
199 int
200 agp_amd64_attach(device_t parent, device_t self, void *aux)
201 {
202 	struct agp_softc *sc = device_private(self);
203 	struct agp_amd64_softc *asc;
204 	struct pci_attach_args *pa = aux;
205 	struct agp_gatt *gatt;
206 	pcitag_t tag;
207 	pcireg_t id, attbase, apctrl;
208 	int maxdevs, i, n;
209 	int error;
210 
211 	asc = malloc(sizeof(struct agp_amd64_softc), M_AGP, M_NOWAIT | M_ZERO);
212 	if (asc == NULL) {
213 		aprint_error(": can't allocate softc\n");
214 		error = ENOMEM;
215 		goto fail0;
216 	}
217 
218 	if (agp_map_aperture(pa, sc, AGP_APBASE) != 0) {
219 		aprint_error(": can't map aperture\n");
220 		error = ENXIO;
221 		goto fail1;
222 	}
223 
224 	maxdevs = pci_bus_maxdevs(pa->pa_pc, 0);
225 	for (i = 0, n = 0; i < maxdevs && n < AMD64_MAX_MCTRL; i++) {
226 		tag = pci_make_tag(pa->pa_pc, 0, i, 3);
227 		id = pci_conf_read(pa->pa_pc, tag, PCI_ID_REG);
228 		if (PCI_VENDOR(id) == PCI_VENDOR_AMD &&
229 		    (PCI_PRODUCT(id) == PCI_PRODUCT_AMD_AMD64_MISC ||
230 		     PCI_PRODUCT(id) == PCI_PRODUCT_AMD_AMD64_F10_MISC)) {
231 			asc->mctrl_tag[n] = tag;
232 			n++;
233 		}
234 	}
235 	if (n == 0) {
236 		aprint_error(": No Miscellaneous Control unit found.\n");
237 		error = ENXIO;
238 		goto fail1;
239 	}
240 	asc->n_mctrl = n;
241 
242 	aprint_normal(": %d Miscellaneous Control unit(s) found.\n",
243 	    asc->n_mctrl);
244 	aprint_normal("%s", device_xname(self));
245 
246 	sc->as_chipc = asc;
247 	sc->as_methods = &agp_amd64_methods;
248 	pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_AGP, &sc->as_capoff,
249 	    NULL);
250 	asc->initial_aperture = AGP_GET_APERTURE(sc);
251 
252 	for (;;) {
253 		gatt = agp_alloc_gatt(sc);
254 		if (gatt)
255 			break;
256 
257 		/*
258 		 * Probably contigmalloc failure. Try reducing the
259 		 * aperture so that the gatt size reduces.
260 		 */
261 		if (AGP_SET_APERTURE(sc, AGP_GET_APERTURE(sc) / 2)) {
262 			error = ENOMEM;
263 			goto fail1;
264 		}
265 	}
266 	asc->gatt = gatt;
267 
268 	switch (PCI_VENDOR(sc->as_id)) {
269 	case PCI_VENDOR_ALI:
270 		agp_amd64_uli_init(sc);
271 		if (agp_amd64_uli_set_aperture(sc, asc->initial_aperture)) {
272 			/* XXX Back out agp_amd64_uli_init?  */
273 			error = ENXIO;
274 			goto fail2;
275 		}
276 		break;
277 
278 	case PCI_VENDOR_NVIDIA:
279 		asc->ctrl_tag = AGP_AMD64_NVIDIA_PCITAG(pa->pa_pc);
280 		agp_amd64_nvidia_init(sc);
281 		if (agp_amd64_nvidia_set_aperture(sc, asc->initial_aperture)) {
282 			/* XXX Back out agp_amd64_nvidia_init?  */
283 			error = ENXIO;
284 			goto fail2;
285 		}
286 		break;
287 
288 	case PCI_VENDOR_VIATECH:
289 		asc->via_agp = agp_amd64_via_match(pa);
290 		if (asc->via_agp) {
291 			asc->ctrl_tag = AGP_AMD64_VIA_PCITAG(pa->pa_pc);
292 			agp_amd64_via_init(sc);
293 			if (agp_amd64_via_set_aperture(sc,
294 			    asc->initial_aperture)) {
295 				/* XXX Back out agp_amd64_via_init?  */
296 				error = ENXIO;
297 				goto fail2;
298 			}
299 		}
300 		break;
301 	}
302 
303 	/* Install the gatt and enable aperture. */
304 	attbase = (uint32_t)(gatt->ag_physical >> 8) & AGP_AMD64_ATTBASE_MASK;
305 	for (i = 0; i < asc->n_mctrl; i++) {
306 		pci_conf_write(pa->pa_pc, asc->mctrl_tag[i], AGP_AMD64_ATTBASE,
307 		    attbase);
308 		apctrl = pci_conf_read(pa->pa_pc, asc->mctrl_tag[i],
309 		    AGP_AMD64_APCTRL);
310 		apctrl |= AGP_AMD64_APCTRL_GARTEN;
311 		apctrl &=
312 		    ~(AGP_AMD64_APCTRL_DISGARTCPU | AGP_AMD64_APCTRL_DISGARTIO);
313 		pci_conf_write(pa->pa_pc, asc->mctrl_tag[i], AGP_AMD64_APCTRL,
314 		    apctrl);
315 	}
316 
317 	agp_flush_cache();
318 
319 	/* Success!  */
320 	return 0;
321 
322 fail2:	agp_free_gatt(sc, gatt);
323 fail1:	free(asc, M_AGP);
324 fail0:	agp_generic_detach(sc);
325 	KASSERT(error);
326 	return error;
327 }
328 
329 
330 static uint32_t agp_amd64_table[] = {
331 	0x02000000,	/*   32 MB */
332 	0x04000000,	/*   64 MB */
333 	0x08000000,	/*  128 MB */
334 	0x10000000,	/*  256 MB */
335 	0x20000000,	/*  512 MB */
336 	0x40000000,	/* 1024 MB */
337 	0x80000000,	/* 2048 MB */
338 };
339 
340 #define AGP_AMD64_TABLE_SIZE \
341 	(sizeof(agp_amd64_table) / sizeof(agp_amd64_table[0]))
342 
343 static uint32_t
344 agp_amd64_get_aperture(struct agp_softc *sc)
345 {
346 	struct agp_amd64_softc *asc = sc->as_chipc;
347 	uint32_t i;
348 
349 	i = (pci_conf_read(sc->as_pc, asc->mctrl_tag[0], AGP_AMD64_APCTRL) &
350 		AGP_AMD64_APCTRL_SIZE_MASK) >> 1;
351 
352 	if (i >= AGP_AMD64_TABLE_SIZE)
353 		return 0;
354 
355 	return agp_amd64_table[i];
356 }
357 
358 static int
359 agp_amd64_set_aperture(struct agp_softc *sc, uint32_t aperture)
360 {
361 	struct agp_amd64_softc *asc = sc->as_chipc;
362 	uint32_t i;
363 	pcireg_t apctrl;
364 	int j;
365 
366 	for (i = 0; i < AGP_AMD64_TABLE_SIZE; i++)
367 		if (agp_amd64_table[i] == aperture)
368 			break;
369 	if (i >= AGP_AMD64_TABLE_SIZE)
370 		return EINVAL;
371 
372 	for (j = 0; j < asc->n_mctrl; j++) {
373 		apctrl = pci_conf_read(sc->as_pc, asc->mctrl_tag[0],
374 		    AGP_AMD64_APCTRL);
375 		pci_conf_write(sc->as_pc, asc->mctrl_tag[0], AGP_AMD64_APCTRL,
376 		    (apctrl & ~(AGP_AMD64_APCTRL_SIZE_MASK)) | (i << 1));
377 	}
378 
379 	switch (PCI_VENDOR(sc->as_id)) {
380 	case PCI_VENDOR_ALI:
381 		return agp_amd64_uli_set_aperture(sc, aperture);
382 		break;
383 
384 	case PCI_VENDOR_NVIDIA:
385 		return agp_amd64_nvidia_set_aperture(sc, aperture);
386 		break;
387 
388 	case PCI_VENDOR_VIATECH:
389 		if (asc->via_agp)
390 			return agp_amd64_via_set_aperture(sc, aperture);
391 		break;
392 	}
393 
394 	return 0;
395 }
396 
397 static int
398 agp_amd64_bind_page(struct agp_softc *sc, off_t offset, bus_addr_t physical)
399 {
400 	struct agp_amd64_softc *asc = sc->as_chipc;
401 
402 	if (offset < 0 || offset >= (asc->gatt->ag_entries << AGP_PAGE_SHIFT))
403 		return EINVAL;
404 
405 	asc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] =
406 	    (physical & 0xfffff000) | ((physical >> 28) & 0x00000ff0) | 3;
407 
408 	return 0;
409 }
410 
411 static int
412 agp_amd64_unbind_page(struct agp_softc *sc, off_t offset)
413 {
414 	struct agp_amd64_softc *asc = sc->as_chipc;
415 
416 	if (offset < 0 || offset >= (asc->gatt->ag_entries << AGP_PAGE_SHIFT))
417 		return EINVAL;
418 
419 	asc->gatt->ag_virtual[offset >> AGP_PAGE_SHIFT] = 0;
420 
421 	return 0;
422 }
423 
424 static void
425 agp_amd64_flush_tlb(struct agp_softc *sc)
426 {
427 	struct agp_amd64_softc *asc = sc->as_chipc;
428 	pcireg_t cachectrl;
429 	int i;
430 
431 	for (i = 0; i < asc->n_mctrl; i++) {
432 		cachectrl = pci_conf_read(sc->as_pc, asc->mctrl_tag[i],
433 		    AGP_AMD64_CACHECTRL);
434 		pci_conf_write(sc->as_pc, asc->mctrl_tag[i],
435 		    AGP_AMD64_CACHECTRL,
436 		    cachectrl | AGP_AMD64_CACHECTRL_INVGART);
437 	}
438 }
439 
440 static void
441 agp_amd64_apbase_fixup(struct agp_softc *sc)
442 {
443 	struct agp_amd64_softc *asc = sc->as_chipc;
444 	uint32_t apbase;
445 	int i;
446 
447 	apbase = pci_conf_read(sc->as_pc, sc->as_tag, AGP_APBASE);
448 	asc->apbase = PCI_MAPREG_MEM_ADDR(apbase);
449 	apbase = (asc->apbase >> 25) & AGP_AMD64_APBASE_MASK;
450 	for (i = 0; i < asc->n_mctrl; i++)
451 		pci_conf_write(sc->as_pc, asc->mctrl_tag[i], AGP_AMD64_APBASE,
452 		    apbase);
453 }
454 
455 static void
456 agp_amd64_uli_init(struct agp_softc *sc)
457 {
458 	struct agp_amd64_softc *asc = sc->as_chipc;
459 	pcireg_t apbase;
460 
461 	agp_amd64_apbase_fixup(sc);
462 	apbase = pci_conf_read(sc->as_pc, sc->as_tag, AGP_AMD64_ULI_APBASE);
463 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD64_ULI_APBASE,
464 	    (apbase & 0x0000000f) | asc->apbase);
465 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD64_ULI_HTT_FEATURE,
466 	    asc->apbase);
467 }
468 
469 static int
470 agp_amd64_uli_set_aperture(struct agp_softc *sc, uint32_t aperture)
471 {
472 	struct agp_amd64_softc *asc = sc->as_chipc;
473 
474 	switch (aperture) {
475 	case 0x02000000:	/*  32 MB */
476 	case 0x04000000:	/*  64 MB */
477 	case 0x08000000:	/* 128 MB */
478 	case 0x10000000:	/* 256 MB */
479 		break;
480 	default:
481 		return EINVAL;
482 	}
483 
484 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD64_ULI_ENU_SCR,
485 	    asc->apbase + aperture - 1);
486 
487 	return 0;
488 }
489 
490 static void
491 agp_amd64_nvidia_init(struct agp_softc *sc)
492 {
493 	struct agp_amd64_softc *asc = sc->as_chipc;
494 	pcireg_t apbase;
495 
496 	agp_amd64_apbase_fixup(sc);
497 	apbase =
498 	    pci_conf_read(sc->as_pc, sc->as_tag, AGP_AMD64_NVIDIA_0_APBASE);
499 	pci_conf_write(sc->as_pc, sc->as_tag, AGP_AMD64_NVIDIA_0_APBASE,
500 	    (apbase & 0x0000000f) | asc->apbase);
501 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP_AMD64_NVIDIA_1_APBASE1,
502 	    asc->apbase);
503 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP_AMD64_NVIDIA_1_APBASE2,
504 	    asc->apbase);
505 }
506 
507 static int
508 agp_amd64_nvidia_set_aperture(struct agp_softc *sc, uint32_t aperture)
509 {
510 	struct agp_amd64_softc *asc = sc->as_chipc;
511 	uint32_t apsize;
512 
513 	switch (aperture) {
514 	case 0x02000000:	apsize = 0x0f;	break;	/*  32 MB */
515 	case 0x04000000:	apsize = 0x0e;	break;	/*  64 MB */
516 	case 0x08000000:	apsize = 0x0c;	break;	/* 128 MB */
517 	case 0x10000000:	apsize = 0x08;	break;	/* 256 MB */
518 	case 0x20000000:	apsize = 0x00;	break;	/* 512 MB */
519 	default:
520 		return EINVAL;
521 	}
522 
523 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP_AMD64_NVIDIA_1_APSIZE,
524 	    (pci_conf_read(sc->as_pc, asc->ctrl_tag,
525 	    AGP_AMD64_NVIDIA_1_APSIZE) & 0xfffffff0) | apsize);
526 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP_AMD64_NVIDIA_1_APLIMIT1,
527 	    asc->apbase + aperture - 1);
528 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP_AMD64_NVIDIA_1_APLIMIT2,
529 	    asc->apbase + aperture - 1);
530 
531 	return 0;
532 }
533 
534 static void
535 agp_amd64_via_init(struct agp_softc *sc)
536 {
537 	struct agp_amd64_softc *asc = sc->as_chipc;
538 
539 	agp_amd64_apbase_fixup(sc);
540 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP3_VIA_ATTBASE,
541 	    asc->gatt->ag_physical);
542 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP3_VIA_GARTCTRL,
543 	    pci_conf_read(sc->as_pc, asc->ctrl_tag, AGP3_VIA_ATTBASE) | 0x180);
544 }
545 
546 static int
547 agp_amd64_via_set_aperture(struct agp_softc *sc, uint32_t aperture)
548 {
549 	struct agp_amd64_softc *asc = sc->as_chipc;
550 	uint32_t apsize;
551 
552 	apsize = ((aperture - 1) >> 20) ^ 0xff;
553 	if ((((apsize ^ 0xff) << 20) | ((1 << 20) - 1)) + 1 != aperture)
554 		return EINVAL;
555 	pci_conf_write(sc->as_pc, asc->ctrl_tag, AGP3_VIA_APSIZE,
556 	    (pci_conf_read(sc->as_pc, asc->ctrl_tag, AGP3_VIA_APSIZE) & ~0xff) |
557 	    apsize);
558 
559 	return 0;
560 }
561