First stab at a VGA arbiter. The VGA arbiter makes sure that only a single

VGA device can be active, and is responsible for routing IO to the active VGA
device.  Processes can use the new PCIOC_GETVGA and PCIOC_SETVGA ioctls
to manipulate the VGA arbiter.

ok deraadt@, oga@

2 files changed, 191 insertions, 3 deletions

diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index 8a95050bf71..c0abc728ba3 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pci.c,v 1.73 2010/01/26 17:47:36 otto Exp $	*/
+/*	$OpenBSD: pci.c,v 1.74 2010/04/21 18:55:40 kettenis Exp $	*/
 /*	$NetBSD: pci.c,v 1.31 1997/06/06 23:48:04 thorpej Exp $	*/
 
 /*
@@ -39,6 +39,7 @@
 #include <sys/systm.h>
 #include <sys/device.h>
 #include <sys/malloc.h>
+#include <sys/proc.h>
 
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcivar.h>
@@ -77,6 +78,11 @@ struct cfdriver pci_cd = {
 
 int	pci_ndomains;
 
+struct proc *pci_vga_proc;
+struct pci_softc *pci_vga_pci;
+pcitag_t pci_vga_tag;
+int	pci_vga_count;
+
 int	pciprint(void *, const char *);
 int	pcisubmatch(struct device *, void *, void *);
 
@@ -87,6 +93,8 @@ int pci_enumerate_bus(struct pci_softc *,
     int (*)(struct pci_attach_args *), struct pci_attach_args *);
 #endif
 int	pci_reserve_resources(struct pci_attach_args *);
+int	pci_count_vga(struct pci_attach_args *);
+int	pci_primary_vga(struct pci_attach_args *);
 
 /*
  * Important note about PCI-ISA bridges:
@@ -167,6 +175,9 @@ pciattach(struct device *parent, struct device *self, void *aux)
 	sc->sc_intrswiz = pba->pba_intrswiz;
 	sc->sc_intrtag = pba->pba_intrtag;
 	pci_enumerate_bus(sc, pci_reserve_resources, NULL);
+	pci_enumerate_bus(sc, pci_count_vga, NULL);
+	if (pci_enumerate_bus(sc, pci_primary_vga, NULL))
+		pci_vga_pci = sc;
 	pci_enumerate_bus(sc, NULL, NULL);
 }
 
@@ -768,6 +779,10 @@ pci_matchbyid(struct pci_attach_args *pa, const struct pci_matchid *ids,
 #define PCIDEBUG(x)
 #endif
 
+void pci_disable_vga(pci_chipset_tag_t, pcitag_t);
+void pci_enable_vga(pci_chipset_tag_t, pcitag_t);
+void pci_route_vga(struct pci_softc *);
+void pci_unroute_vga(struct pci_softc *);
 
 int pciopen(dev_t dev, int oflags, int devtype, struct proc *p);
 int pciclose(dev_t dev, int flag, int devtype, struct proc *p);
@@ -798,6 +813,8 @@ int
 pciclose(dev_t dev, int flag, int devtype, struct proc *p)
 {
 	PCIDEBUG(("pciclose\n"));
+
+	pci_vga_proc = NULL;
 	return (0);
 }
 
@@ -809,7 +826,7 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 	struct pci_rom *rom;
 	int i, error;
 	pcitag_t tag;
-	struct pci_softc *pci = NULL;
+	struct pci_softc *pci;
 	pci_chipset_tag_t pc;
 
 	switch (cmd) {
@@ -822,6 +839,11 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 	case PCIOCGETROMLEN:
 	case PCIOCGETROM:
 		break;
+	case PCIOCGETVGA:
+	case PCIOCSETVGA:
+		if (pci_vga_pci == NULL)
+			return EINVAL;
+		break;
 	default:
 		return ENOTTY;
 	}
@@ -950,6 +972,65 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 		break;
 	}
 
+	case PCIOCGETVGA:
+	{
+		struct pci_vga *vga = (struct pci_vga *)data;
+		int bus, device, function;
+
+		pci_decompose_tag(pci_vga_pci->sc_pc, pci_vga_tag,
+		    &bus, &device, &function);
+		vga->pv_sel.pc_bus = bus;
+		vga->pv_sel.pc_dev = device;
+		vga->pv_sel.pc_func = function;
+		error = 0;
+		break;
+	}
+	case PCIOCSETVGA:
+	{
+		struct pci_vga *vga = (struct pci_vga *)data;
+
+		switch (vga->pv_lock) {
+		case PCI_VGA_UNLOCK:
+		case PCI_VGA_LOCK:
+		case PCI_VGA_TRYLOCK:
+			break;
+		default:
+			return (EINVAL);
+		}
+
+		if (vga->pv_lock == PCI_VGA_UNLOCK) {
+			if (pci_vga_proc != p)
+				return (EINVAL);
+			pci_vga_proc = NULL;
+			wakeup(&pci_vga_proc);
+			return (0);
+		}
+
+		while (pci_vga_proc != p && pci_vga_proc != NULL) {
+			if (vga->pv_lock == PCI_VGA_TRYLOCK)
+				return (EBUSY);
+			error = tsleep(&pci_vga_proc, PLOCK | PCATCH,
+			    "vgalk", 0);
+			if (error)
+				return (error);
+		}
+		pci_vga_proc = p;
+
+		if (tag != pci_vga_tag) {
+			pci_disable_vga(pci_vga_pci->sc_pc, pci_vga_tag);
+			if (pci != pci_vga_pci) {
+				pci_unroute_vga(pci_vga_pci);
+				pci_route_vga(pci);
+				pci_vga_pci = pci;
+			}
+			pci_enable_vga(pc, tag);
+			pci_vga_tag = tag;
+		}
+
+		error = 0;
+		break;
+	}
+
 	default:
 		error = ENOTTY;
 		break;
@@ -959,3 +1040,96 @@ pciioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p)
 }
 
 #endif
+
+void
+pci_disable_vga(pci_chipset_tag_t pc, pcitag_t tag)
+{
+	pcireg_t csr;
+
+	csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
+	csr &= ~(PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE);
+	pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
+}
+
+void
+pci_enable_vga(pci_chipset_tag_t pc, pcitag_t tag)
+{
+	pcireg_t csr;
+
+	csr = pci_conf_read(pc, tag, PCI_COMMAND_STATUS_REG);
+	csr |= PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE;
+	pci_conf_write(pc, tag, PCI_COMMAND_STATUS_REG, csr);
+}
+
+void
+pci_route_vga(struct pci_softc *sc)
+{
+	pci_chipset_tag_t pc;
+	pcireg_t bc;
+
+	if (sc->sc_bridgetag == NULL)
+		return;
+
+	bc = pci_conf_read(pc, *sc->sc_bridgetag, PPB_REG_BRIDGECONTROL);
+	bc |= PPB_BC_VGA_ENABLE;
+	pci_conf_write(pc, *sc->sc_bridgetag, PPB_REG_BRIDGECONTROL, bc);
+
+	pci_route_vga((struct pci_softc *)sc->sc_dev.dv_parent->dv_parent);
+}
+
+void
+pci_unroute_vga(struct pci_softc *sc)
+{
+	pci_chipset_tag_t pc;
+	pcireg_t bc;
+
+	if (sc->sc_bridgetag == NULL)
+		return;
+
+	bc = pci_conf_read(pc, *sc->sc_bridgetag, PPB_REG_BRIDGECONTROL);
+	bc &= ~PPB_BC_VGA_ENABLE;
+	pci_conf_write(pc, *sc->sc_bridgetag, PPB_REG_BRIDGECONTROL, bc);
+
+	pci_unroute_vga((struct pci_softc *)sc->sc_dev.dv_parent->dv_parent);
+}
+
+int
+pci_count_vga(struct pci_attach_args *pa)
+{
+	/* XXX For now, only handle the first PCI domain. */
+	if (pa->pa_domain != 0)
+		return (0);
+
+	if ((PCI_CLASS(pa->pa_class) != PCI_CLASS_DISPLAY ||
+	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_DISPLAY_VGA) &&
+	    (PCI_CLASS(pa->pa_class) != PCI_CLASS_PREHISTORIC ||
+	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_PREHISTORIC_VGA))
+		return (0);
+
+	pci_vga_count++;
+
+	return (0);
+}
+
+int
+pci_primary_vga(struct pci_attach_args *pa)
+{
+	/* XXX For now, only handle the first PCI domain. */
+	if (pa->pa_domain != 0)
+		return (0);
+
+	if ((PCI_CLASS(pa->pa_class) != PCI_CLASS_DISPLAY ||
+	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_DISPLAY_VGA) &&
+	    (PCI_CLASS(pa->pa_class) != PCI_CLASS_PREHISTORIC ||
+	    PCI_SUBCLASS(pa->pa_class) != PCI_SUBCLASS_PREHISTORIC_VGA))
+		return (0);
+
+	if ((pci_conf_read(pa->pa_pc, pa->pa_tag, PCI_COMMAND_STATUS_REG)
+	    & (PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE))
+	    != (PCI_COMMAND_IO_ENABLE | PCI_COMMAND_MEM_ENABLE))
+		return (0);
+
+	pci_vga_tag = pa->pa_tag;
+
+	return (1);
+}
diff --git a/sys/sys/pciio.h b/sys/sys/pciio.h
index c00bb14405d..2e40f411c74 100644
--- a/sys/sys/pciio.h
+++ b/sys/sys/pciio.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pciio.h,v 1.5 2009/11/05 20:30:47 kettenis Exp $	*/
+/*	$OpenBSD: pciio.h,v 1.6 2010/04/21 18:55:40 kettenis Exp $	*/
 
 /*-
  * Copyright (c) 1997, Stefan Esser <se@FreeBSD.ORG>
@@ -54,10 +54,24 @@ struct pci_rom {
 	char		*pr_rom;
 };
 
+struct pci_vga {
+	struct pcisel	pv_sel;
+	int		pv_lock;
+	int		pv_decode;
+};
+
+#define	PCI_VGA_UNLOCK		0x00
+#define	PCI_VGA_LOCK		0x01
+#define	PCI_VGA_TRYLOCK		0x02
+
+#define	PCI_VGA_IO_ENABLE	0x01
+#define	PCI_VGA_MEM_ENABLE	0x02
 
 #define	PCIOCREAD	_IOWR('p', 2, struct pci_io)
 #define	PCIOCWRITE	_IOWR('p', 3, struct pci_io)
 #define	PCIOCGETROMLEN	_IOWR('p', 4, struct pci_rom)
 #define	PCIOCGETROM	_IOWR('p', 5, struct pci_rom)
+#define	PCIOCGETVGA	_IOWR('p', 6, struct pci_vga)
+#define	PCIOCSETVGA	_IOWR('p', 7, struct pci_vga)
 
 #endif /* !_SYS_PCIIO_H_ */