Make agp attach as a device. This means that many more agp bridges

actually get detected and attached. Also adds a kernel api for
manipulating agp.

Enable this on i386 and amd64.

"I think you should commit it" deraadt@, ok matthieu. Looked over by
several others.

10 files changed, 166 insertions, 120 deletions

diff --git a/sys/arch/amd64/amd64/conf.c b/sys/arch/amd64/amd64/conf.c
index 9f1323cb280..eed892fe3b6 100644
--- a/sys/arch/amd64/amd64/conf.c
+++ b/sys/arch/amd64/amd64/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.16 2007/09/12 18:18:27 deraadt Exp $	*/
+/*	$OpenBSD: conf.c,v 1.17 2007/11/25 17:11:12 oga Exp $	*/
 
 /*
  * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
@@ -171,6 +171,8 @@ cdev_decl(cztty);
 #include "radio.h"
 #include "nvram.h"
 cdev_decl(nvram);
+#include "agp.h"
+cdev_decl(agp);
 
 #include "wsdisplay.h"
 #include "wskbd.h"
@@ -293,6 +295,7 @@ struct cdevsw	cdevsw[] =
 	cdev_acpi_init(NACPI,acpi),	/* 83: ACPI */
 	cdev_bthub_init(NBTHUB,bthub),	/* 84: bthub */
 	cdev_nvram_init(NNVRAM,nvram),	/* 85: NVRAM interface */
+	cdev_agp_init(NAGP,agp),	/* 86: agp */
 };
 int	nchrdev = sizeof(cdevsw) / sizeof(cdevsw[0]);
 
diff --git a/sys/arch/amd64/conf/GENERIC b/sys/arch/amd64/conf/GENERIC
index e0d1bb9ca78..ae3264f79a0 100644
--- a/sys/arch/amd64/conf/GENERIC
+++ b/sys/arch/amd64/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.205 2007/11/25 12:00:46 jsg Exp $
+#	$OpenBSD: GENERIC,v 1.206 2007/11/25 17:11:12 oga Exp $
 #
 # For further information on compiling OpenBSD kernels, see the config(8)
 # man page.
@@ -64,6 +64,8 @@ pci*	at pchb?
 pcib*	at pci?			# PCI-ISA bridge
 amdpcib* at pci?		# AMD 8111 LPC bridge
 
+agp* 	at pchb?		# AGP bridge
+
 # National Semiconductor LM7[89] and compatible hardware monitors
 lm0	at isa? port 0x290
 #lm1	at isa? port 0x280
@@ -237,7 +239,6 @@ pms*		at pckbc?		# PS/2 mouse for wsmouse
 pmsi*		at pckbc?		# PS/2 "Intelli"mouse for wsmouse
 vga0		at isa?
 vga*		at pci?
-option		PCIAGP
 wsdisplay*	at vga?
 wskbd*		at pckbd? mux 1
 wsmouse*	at pms? mux 0
diff --git a/sys/arch/amd64/conf/files.amd64 b/sys/arch/amd64/conf/files.amd64
index 6cd06816c70..5ab5f20a899 100644
--- a/sys/arch/amd64/conf/files.amd64
+++ b/sys/arch/amd64/conf/files.amd64
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.amd64,v 1.36 2007/10/10 15:53:51 art Exp $
+#	$OpenBSD: files.amd64,v 1.37 2007/11/25 17:11:12 oga Exp $
 
 maxpartitions 16
 maxusers 2 16 128
@@ -102,8 +102,12 @@ file	arch/amd64/pci/pciide_machdep.c		pciide
 
 include	"dev/puc/files.puc"
 
+# AGP
+include "dev/pci/files.agp"
+file	arch/amd64/pci/agp_machdep.c		agp
+
 # PCI Host bridge chipsets
-device	pchb: pcibus
+device	pchb: pcibus, agpbus, agp_i810
 attach	pchb at pci
 file	arch/amd64/pci/pchb.c			pchb
 
@@ -222,6 +226,3 @@ major	{cd = 6}
 major	{rd = 17}
 major	{wd = 0}
 major	{fd = 2}
-
-file	arch/amd64/pci/agp_machdep.c		pciagp
-file	dev/pci/agp_i810.c			pciagp
diff --git a/sys/arch/amd64/pci/agp_machdep.c b/sys/arch/amd64/pci/agp_machdep.c
index ff725b830cb..6237588010d 100644
--- a/sys/arch/amd64/pci/agp_machdep.c
+++ b/sys/arch/amd64/pci/agp_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: agp_machdep.c,v 1.2 2007/08/04 19:40:25 reyk Exp $	*/
+/*	$OpenBSD: agp_machdep.c,v 1.3 2007/11/25 17:11:12 oga Exp $	*/
 
 /*
  * Copyright (c) 2002 Michael Shalayeff
@@ -36,16 +36,6 @@
 
 #include <machine/cpufunc.h>
 
-const struct agp_product agp_products[] = {
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915G_IV, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915GM_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945G_IGD_1, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945GM_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82965_IGD_1, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82965GM_IGD_1, agp_i810_attach },
-	{ 0, 0, NULL }
-};
-
 void
 agp_flush_cache(void)
 {
diff --git a/sys/arch/amd64/pci/pchb.c b/sys/arch/amd64/pci/pchb.c
index 358a82dd976..dfd27f45f4b 100644
--- a/sys/arch/amd64/pci/pchb.c
+++ b/sys/arch/amd64/pci/pchb.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pchb.c,v 1.11 2007/11/16 15:31:19 mikeb Exp $	*/
+/*	$OpenBSD: pchb.c,v 1.12 2007/11/25 17:11:12 oga Exp $	*/
 /*	$NetBSD: pchb.c,v 1.1 2003/04/26 18:39:50 fvdl Exp $	*/
 /*
  * Copyright (c) 2000 Michael Shalayeff
@@ -73,6 +73,8 @@
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcidevs.h>
 
+#include <dev/pci/agpvar.h>
+
 #include <dev/rndvar.h>
 
 #include <dev/ic/i82802reg.h>
@@ -128,6 +130,7 @@ int	pchbmatch(struct device *, void *, void *);
 void	pchbattach(struct device *, struct device *, void *);
 
 int	pchb_print(void *, const char *);
+int	agpbus_print(void *, const char *);
 void	pchb_rnd(void *);
 void	pchb_amd64ht_attach (struct device *, struct pci_attach_args *, int);
 
@@ -157,7 +160,10 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 {
 	struct pchb_softc *sc = (struct pchb_softc *)self;
 	struct pci_attach_args *pa = aux;
-	int i, r;
+	struct agpbus_attach_args apa;
+	int has_agp, i, r;
+
+	has_agp = 0;
 
 	switch (PCI_VENDOR(pa->pa_id)) {
 	case PCI_VENDOR_AMD:
@@ -169,9 +175,6 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 		}
 		break;
 	case PCI_VENDOR_INTEL:
-#ifdef PCIAGP
-		pciagp_set_pchb(pa);
-#endif
 		switch (PCI_PRODUCT(pa->pa_id)) {
 		case PCI_PRODUCT_INTEL_82915G_HB:
 		case PCI_PRODUCT_INTEL_82925X_HB:
@@ -217,6 +220,20 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 		break;
 	}
 	printf("\n");
+
+	/*
+	 * If we haven't detected AGP yet (via a product ID),
+	 * then check for AGP capability on the device.
+	 */
+	if (has_agp ||
+	    pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_AGP,
+			       NULL, NULL) != 0) {
+		printf("\n");
+		apa.apa_busname = "agp";
+		apa.apa_pci_args = *pa;
+		config_found(self, &apa, agpbus_print);
+		printf("\n");
+	}
 }
 
 int
@@ -230,6 +247,14 @@ pchb_print(void *aux, const char *pnp)
 	return (UNCONF);
 }
 
+int
+agpbus_print(void *vaa, const char *pnp)
+{
+	if (pnp)
+		printf("agp at %s", pnp);
+	return (UNCONF);
+}
+
 void
 pchb_amd64ht_attach(struct device *self, struct pci_attach_args *pa, int i)
 {
diff --git a/sys/arch/i386/conf/GENERIC b/sys/arch/i386/conf/GENERIC
index 295fd8571ec..12d6c098087 100644
--- a/sys/arch/i386/conf/GENERIC
+++ b/sys/arch/i386/conf/GENERIC
@@ -1,4 +1,4 @@
-#	$OpenBSD: GENERIC,v 1.590 2007/11/25 12:00:46 jsg Exp $
+#	$OpenBSD: GENERIC,v 1.591 2007/11/25 17:11:12 oga Exp $
 #
 # For further information on compiling OpenBSD kernels, see the config(8)
 # man page.
@@ -90,6 +90,7 @@ gpio*	at gscpcib?
 glxpcib* at pci?		# AMD CS5536 PCI-ISA bridge
 gpio*	at glxpcib?
 
+agp*	at pchb?		# AGP bridges
 # power management and other environmental stuff
 elansc*	at pci?			# AMD Elan SC520 System Controller
 gpio*	at elansc?
@@ -300,7 +301,6 @@ pckbd*		at pckbc?	# PC keyboard
 pms*		at pckbc?	# PS/2 mouse for wsmouse
 pmsi*		at pckbc?	# PS/2 "Intelli"mouse for wsmouse
 vga0		at isa?
-option		PCIAGP
 vga*		at pci?
 pcdisplay0	at isa?		# CGA, MDA, EGA, HGA
 wsdisplay*	at vga?
diff --git a/sys/arch/i386/conf/files.i386 b/sys/arch/i386/conf/files.i386
index cff1f90b9de..0466e09ec8e 100644
--- a/sys/arch/i386/conf/files.i386
+++ b/sys/arch/i386/conf/files.i386
@@ -1,4 +1,4 @@
-#	$OpenBSD: files.i386,v 1.168 2007/11/25 15:42:15 tedu Exp $
+#	$OpenBSD: files.i386,v 1.169 2007/11/25 17:11:12 oga Exp $
 #
 # new style config file for i386 architecture
 #
@@ -96,19 +96,15 @@ file	arch/i386/i386/mainbus.c	mainbus
 #
 
 include "../../../dev/pci/files.pci"
+include "../../../dev/pci/files.agp"
 file	arch/i386/pci/pci_machdep.c		pci
-file	arch/i386/pci/agp_machdep.c		pciagp
-file	dev/pci/agp_ali.c			pciagp
-file	dev/pci/agp_amd.c			pciagp
-file	dev/pci/agp_i810.c			pciagp
-file	dev/pci/agp_intel.c			pciagp
-file	dev/pci/agp_sis.c			pciagp
-file	dev/pci/agp_via.c			pciagp
+file	arch/i386/pci/agp_machdep.c		agp
 file	arch/i386/pci/pciide_machdep.c		pciide
 file	arch/i386/pci/pcic_pci_machdep.c	pcic_pci
 
 # PCI-Host bridge chipsets
-device	pchb: pcibus
+device  pchb: pcibus, agpbus, agp_ali, agp_amd, agp_i810, agp_intel, agp_sis,
+              agp_via
 attach	pchb at pci
 file	arch/i386/pci/pchb.c		pchb
 
diff --git a/sys/arch/i386/i386/conf.c b/sys/arch/i386/i386/conf.c
index cdd1f90f7da..867bbc7c853 100644
--- a/sys/arch/i386/i386/conf.c
+++ b/sys/arch/i386/i386/conf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: conf.c,v 1.120 2007/11/25 15:42:15 tedu Exp $	*/
+/*	$OpenBSD: conf.c,v 1.121 2007/11/25 17:11:12 oga Exp $	*/
 /*	$NetBSD: conf.c,v 1.75 1996/05/03 19:40:20 christos Exp $	*/
 
 /*
@@ -174,6 +174,8 @@ cdev_decl(cztty);
 #include "gpr.h"
 #include "nvram.h"
 cdev_decl(nvram);
+#include "agp.h"
+cdev_decl(agp);
 
 /* XXX -- this needs to be supported by config(8)! */
 #if (NCOM > 0) && (NPCCOM > 0)
@@ -307,6 +309,7 @@ struct cdevsw	cdevsw[] =
 	cdev_nvram_init(NNVRAM,nvram),	/* 84: NVRAM interface */
 	cdev_notdef(),			/* 85: ACPI (deprecated) */
 	cdev_bthub_init(NBTHUB,bthub),	/* 86: bthub */
+	cdev_agp_init(NAGP,agp),	/* 87: agp */
 };
 int	nchrdev = sizeof(cdevsw) / sizeof(cdevsw[0]);
 
diff --git a/sys/arch/i386/pci/agp_machdep.c b/sys/arch/i386/pci/agp_machdep.c
index dae50a45006..507428a94d2 100644
--- a/sys/arch/i386/pci/agp_machdep.c
+++ b/sys/arch/i386/pci/agp_machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: agp_machdep.c,v 1.8 2007/08/04 19:40:25 reyk Exp $	*/
+/*	$OpenBSD: agp_machdep.c,v 1.9 2007/11/25 17:11:12 oga Exp $	*/
 
 /*
  * Copyright (c) 2002 Michael Shalayeff
@@ -36,29 +36,6 @@
 
 #include <machine/cpufunc.h>
 
-const struct agp_product agp_products[] = {
-	{ PCI_VENDOR_ALI, -1, agp_ali_attach },
-	{ PCI_VENDOR_AMD, -1, agp_amd_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810_GC, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810_DC100_GC, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82810E_GC, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82815_FULL_GRAPH, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82830MP_IV, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82845G_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82852GM_AGP, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82865_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915G_IV, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82915GM_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945G_IGD_1, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82945GM_IGD, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82965_IGD_1, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, PCI_PRODUCT_INTEL_82965GM_IGD_1, agp_i810_attach },
-	{ PCI_VENDOR_INTEL, -1, agp_intel_attach },
-	{ PCI_VENDOR_SIS, -1, agp_sis_attach },
-	{ PCI_VENDOR_VIATECH, -1, agp_via_attach },
-	{ 0, 0, NULL }
-};
-
 void
 agp_flush_cache(void)
 {
diff --git a/sys/arch/i386/pci/pchb.c b/sys/arch/i386/pci/pchb.c
index 406ff34d4fd..081dcaed476 100644
--- a/sys/arch/i386/pci/pchb.c
+++ b/sys/arch/i386/pci/pchb.c
@@ -1,5 +1,5 @@
-/*	$OpenBSD: pchb.c,v 1.57 2007/11/16 15:31:19 mikeb Exp $	*/
-/*	$NetBSD: pchb.c,v 1.6 1997/06/06 23:29:16 thorpej Exp $	*/
+/*	$OpenBSD: pchb.c,v 1.58 2007/11/25 17:11:12 oga Exp $ */
+/*	$NetBSD: pchb.c,v 1.65 2007/08/15 02:26:13 markd Exp $	*/
 
 /*
  * Copyright (c) 2000 Michael Shalayeff
@@ -27,7 +27,7 @@
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 /*-
- * Copyright (c) 1996 The NetBSD Foundation, Inc.
+ * Copyright (c) 1996, 1998, 2000 The NetBSD Foundation, Inc.
  * All rights reserved.
  *
  * This code is derived from software contributed to The NetBSD Foundation
@@ -74,6 +74,9 @@
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcidevs.h>
 
+#include <dev/pci/agpreg.h>
+#include <dev/pci/agpvar.h>
+
 #include <dev/rndvar.h>
 
 #include <dev/ic/i82802reg.h>
@@ -130,6 +133,7 @@ int	pchbmatch(struct device *, void *, void *);
 void	pchbattach(struct device *, struct device *, void *);
 
 int	pchb_print(void *, const char *);
+int	agpbus_print(void *, const char *);
 
 struct cfattach pchb_ca = {
 	sizeof(struct pchb_softc), pchbmatch, pchbattach
@@ -180,35 +184,27 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 	struct pchb_softc *sc = (struct pchb_softc *)self;
 	struct pci_attach_args *pa = aux;
 	struct pcibus_attach_args pba;
+	struct agpbus_attach_args apa;
 	pcireg_t bcreg;
 	u_char bdnum, pbnum;
 	pcitag_t tag;
-	int neednl = 1;
-	int i, r;
+	int doattach, has_agp, i, r;
+
+	doattach = 0;
+	has_agp = 0;
 
 	/*
-	 * Print out a description, and configure certain chipsets which
-	 * have auxiliary PCI buses.
+	 * configure certain chipsets which have auxiliary PCI buses.
 	 */
 
 	switch (PCI_VENDOR(pa->pa_id)) {
-#ifdef PCIAGP
-	case PCI_VENDOR_ALI:
-	case PCI_VENDOR_SIS:
-	case PCI_VENDOR_VIATECH:
-		pciagp_set_pchb(pa);
-		break;
-#endif
 	case PCI_VENDOR_AMD:
 		switch (PCI_PRODUCT(pa->pa_id)) {
-#ifdef PCIAGP
 		case PCI_PRODUCT_AMD_SC751_SC:
 		case PCI_PRODUCT_AMD_762_PCHB:
-			pciagp_set_pchb(pa);
+			has_agp =1; /* XXX is this detected otherwise */
 			break;
-#endif
 		case PCI_PRODUCT_AMD_AMD64_HT:
-			neednl = 0;
 			printf("\n");
 			for (i = 0; i < AMD64HT_NUM_LDT; i++)
 				pchb_amd64ht_attach(self, pa, i);
@@ -227,23 +223,20 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 		 * This host bridge has a second PCI bus.
 		 * Configure it.
 		 */
-		neednl = 0;
-		pba.pba_busname = "pci";
-		pba.pba_iot = pa->pa_iot;
-		pba.pba_memt = pa->pa_memt;
-		pba.pba_dmat = pa->pa_dmat;
-		pba.pba_domain = pa->pa_domain;
-		pba.pba_bus = bdnum;
+		pbnum = bdnum;
 		pba.pba_bridgetag = NULL;
-		pba.pba_pc = pa->pa_pc;
-		printf("\n");
-		config_found(self, &pba, pchb_print);
+		doattach = 1;
 		break;
 	case PCI_VENDOR_INTEL:
-#ifdef PCIAGP
-		pciagp_set_pchb(pa);
-#endif
 		switch (PCI_PRODUCT(pa->pa_id)) {
+		case PCI_PRODUCT_INTEL_82452_HB:
+			bcreg = pci_conf_read(pa->pa_pc, pa->pa_tag, 0x40);
+			pbnum = PCISET_INTEL_BRIDGE_NUMBER(bcreg);
+			if (pbnum != 0xff) {
+				pbnum++;
+				doattach = 1;
+			}
+			break;
 		case PCI_PRODUCT_INTEL_82443BX_AGP:     /* 82443BX AGP (PAC) */
 		case PCI_PRODUCT_INTEL_82443BX_NOAGP:   /* 82443BX Host-PCI (no AGP) */
 			/*
@@ -274,24 +267,25 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 				break;
 			case PCISET_INTEL_TYPE_AUX:
 				printf(": Auxiliary PB (bus %d)", pbnum);
-				neednl = 0;
 
 				/*
 				 * This host bridge has a second PCI bus.
 				 * Configure it.
 				 */
-				pba.pba_busname = "pci";
-				pba.pba_iot = pa->pa_iot;
-				pba.pba_memt = pa->pa_memt;
-				pba.pba_dmat = pa->pa_dmat;
-				pba.pba_domain = pa->pa_domain;
-				pba.pba_bus = pbnum;
-				pba.pba_pc = pa->pa_pc;
-				printf("\n");
-				config_found(self, &pba, pchb_print);
+				doattach = 1;
 				break;
 			}
 			break;
+		case PCI_PRODUCT_INTEL_CDC:
+			bcreg = pci_conf_read(pa->pa_pc, pa->pa_tag,
+			    I82424_CPU_BCTL_REG);
+			if (bcreg & I82424_BCTL_CPUPCI_POSTEN) {
+				bcreg &= ~I82424_BCTL_CPUPCI_POSTEN;
+				pci_conf_write(pa->pa_pc, pa->pa_tag,
+				    I82424_CPU_BCTL_REG, bcreg);
+				printf(": disabled CPU-PCI write posting");
+			}
+			break;
 		case PCI_PRODUCT_INTEL_82454NX:
 			pbnum = 0;
 			switch (pa->pa_device) {
@@ -317,27 +311,47 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 				break;
 			}
 			if (pbnum != 0) {
-				pba.pba_busname = "pci";
-				pba.pba_iot = pa->pa_iot;
-				pba.pba_memt = pa->pa_memt;
-				pba.pba_dmat = pa->pa_dmat;
-				pba.pba_domain = pa->pa_domain;
-				pba.pba_bus = pbnum;
-				pba.pba_pc = pa->pa_pc;
-				printf("\n");
-				config_found(self, &pba, pchb_print);
+				doattach = 1;
 			}
 			break;
-		case PCI_PRODUCT_INTEL_CDC:
-			bcreg = pci_conf_read(pa->pa_pc, pa->pa_tag,
-			    I82424_CPU_BCTL_REG);
-			if (bcreg & I82424_BCTL_CPUPCI_POSTEN) {
-				bcreg &= ~I82424_BCTL_CPUPCI_POSTEN;
-				pci_conf_write(pa->pa_pc, pa->pa_tag,
-				    I82424_CPU_BCTL_REG, bcreg);
-				printf(": disabled CPU-PCI write posting");
-			}
+		case PCI_PRODUCT_INTEL_82810_MCH:
+		case PCI_PRODUCT_INTEL_82810_DC100_MCH:
+		case PCI_PRODUCT_INTEL_82810E_MCH:
+		case PCI_PRODUCT_INTEL_82815_FULL_HUB:
+		case PCI_PRODUCT_INTEL_82830MP_IO_1:
+		case PCI_PRODUCT_INTEL_82845G:
+		case PCI_PRODUCT_INTEL_82852GM_HPB:
+		case PCI_PRODUCT_INTEL_82865_IO_1:
+		case PCI_PRODUCT_INTEL_82915G_HB:
+		case PCI_PRODUCT_INTEL_82915GM_HB:
+		case PCI_PRODUCT_INTEL_82945GP_MCH:
+		case PCI_PRODUCT_INTEL_82945GM_MCH:
+		case PCI_PRODUCT_INTEL_82Q963_HB:
+		case PCI_PRODUCT_INTEL_82965_MCH:
+			/*
+			 * The host bridge is either in GFX mode (internal
+			 * graphics) or in AGP mode. In GFX mode, we pretend
+			 * to have AGP because the graphics memory access
+			 * is very similar and the AGP GATT code will
+			 * deal with this. In the latter case, the
+			 * pci_get_capability(PCI_CAP_AGP) test below will
+			 * fire, so we do no harm by already setting the flag.
+			 */
+			has_agp = 1;
+			break;
+		}
+		break;
+		default:
 			break;
+	}
+
+	/*
+	 * Now set up RNG.  this isn't in previous switch since only
+	 * some of the rng devices need special attention for AGP
+	 */
+	switch (PCI_VENDOR(pa->pa_id)) {
+	case PCI_VENDOR_INTEL:
+		switch (PCI_PRODUCT(pa->pa_id)) {
 		case PCI_PRODUCT_INTEL_82810_MCH:
 		case PCI_PRODUCT_INTEL_82810_DC100_MCH:
 		case PCI_PRODUCT_INTEL_82810E_MCH:
@@ -388,8 +402,36 @@ pchbattach(struct device *parent, struct device *self, void *aux)
 			break;
 		}
 	}
-	if (neednl)
+
+	/*
+	 * If we haven't detected AGP yet (via a product ID),
+	 * then check for AGP capability on the device.
+	 */
+	if (has_agp ||
+	    pci_get_capability(pa->pa_pc, pa->pa_tag, PCI_CAP_AGP,
+			       NULL, NULL) != 0) {
+		printf("\n");
+		apa.apa_busname = "agp";
+		apa.apa_pci_args = *pa;
+		config_found(self, &apa, agpbus_print);
 		printf("\n");
+	}
+
+	if (doattach) {
+		pba.pba_busname = "pci";
+		pba.pba_iot = pa->pa_iot;
+		pba.pba_memt = pa->pa_memt;
+		pba.pba_dmat = pa->pa_dmat;
+		pba.pba_domain = pa->pa_domain;
+		pba.pba_bus = pbnum;
+		pba.pba_bridgetag = NULL;
+		pba.pba_pc = pa->pa_pc;
+		printf("\n");
+		config_found(self, &pba, pchb_print);
+		pba.pba_bridgetag = NULL;
+		memset(&pba.pba_intrtag, 0, sizeof(pba.pba_intrtag));
+		config_found(self, &pba, pchb_print);
+	}
 }
 
 int
@@ -403,6 +445,14 @@ pchb_print(void *aux, const char *pnp)
 	return (UNCONF);
 }
 
+int
+agpbus_print(void *vaa, const char *pnp)
+{
+	if (pnp)
+		printf("agp at %s", pnp);
+	return (UNCONF);
+}
+
 /*
  * Should do FIPS testing as per:
  *	http://csrc.nist.gov/publications/fips/fips140-1/fips1401.pdf