NetBSD/share/man/man4/agp.4

.\"     $NetBSD: agp.4,v 1.9 2002/02/20 20:28:18 gmcgarry Exp $
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.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Gregory McGarry.
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.Dd September 11, 2001
.Dt AGP 4
.Os
.Sh NAME
.Nm agp
.Nd accelerated graphics port driver
.Sh SYNOPSIS
.Cd "agp* at pchb?"
.Sh DESCRIPTION
The
.Nm
driver provides machine-independent support for the accelerated
graphics port (AGP) found on many PC-based and PCI systems.  The AGP
specification was designed by Intel.
.Pp
The AGP chipset is positioned between the PCI-Host bridge and the
graphics accelerator to provide a high-performance dedicated graphics
bus for moving large amounts of data directly from host memory to the
graphics accelerator.  The specification currently supports a peak
bandwidth of 528 MB/s.  AGP uses a Graphics Address Remapping Table
(GART) to provide a physically-contiguous view of scattered pages in
host memory for DMA transfers.
.Pp
The
.Nm
driver supports the following chipsets:
.Pp
.Bl -dash -compact -offset indent
.It
ALI M1541 host-to-AGP bridge
.It
AMD 751 and 761 host-to-AGP bridges
.It
Intel 82810, 82810-DC100, 82810E, and 82815 SVGA controllers
.It
SiS 5591 host-to-AGP bridge
.It
VIA
.El
.Pp
The
.Nm
driver also provides an interface to user processes for use by X
servers.  A user process communicates to the device initially by means
of
.Xr ioctl 2
calls.  The calls supported are:
.Bl -tag -width indent
.It Dv AGPIOC_INFO
Get AGP information, setting the members in the
.Em agp_info
structure as defined in \*[Lt]sys/agpio.h\*[Gt]:
.Bd -literal
typedef struct _agp_info {
        agp_version version;    /* version of the driver        */
        u_int32_t bridge_id;    /* bridge vendor/device         */
        u_int32_t agp_mode;     /* mode info of bridge          */
        off_t aper_base;        /* base of aperture             */
        size_t aper_size;       /* size of aperture             */
        size_t pg_total;        /* max pages (swap + system)    */
        size_t pg_system;       /* max pages (system)           */
        size_t pg_used;         /* current pages used           */
} agp_info;
.Ed
.It Dv AGPIOC_ACQUIRE
Acquire AGP.
.It Dv AGPIOC_RELEASE
Release AGP.
.It Dv AGPIOC_SETUP
Setup AGP, using the members in the
.Em agp_setup
structure as defined in \*[Lt]sys/agpio.h\*[Gt]:
.Bd -literal
typedef struct _agp_setup {
        u_int32_t agp_mode;     /* mode info of bridge          */
} agp_setup;
.Ed
.It Dv AGPIOC_ALLOCATE
Allocate AGP space, using and setting the members in the
.Em agp_allocate
structure as defined in \*[Lt]sys/agpio.h\*[Gt]:
.Bd -literal
typedef struct _agp_allocate {
        int key;                /* tag of allocation            */
        size_t pg_count;        /* number of pages              */
        u_int32_t type;         /* 0 == normal, other devspec   */
        paddr_t physical;       /* device specific (some devices
                                 * need a phys address of the
                                 * actual page behind the gatt
                                 * table)                       */
} agp_allocate;
.Ed
.It Dv AGPIOC_DEALLOCATE
Deallocate AGP space.
.It Dv AGPIOC_BIND
Bind AGP space, using the members in the
.Em agp_bind
structure as defined in \*[Lt]sys/agpio.h\*[Gt]:
.Bd -literal
typedef struct _agp_bind {
        int key;                /* tag of allocation            */
        off_t pg_start;         /* starting page to populate    */
} agp_bind;
.Ed
.It Dv AGPIOC_UNBIND
Unbind AGP space, using the members in the
.Em agp_unbind
structure as defined in \*[Lt]sys/agpio.h\*[Gt]:
.Bd -literal
typedef struct _agp_unbind {
        int key;                /* tag of allocation            */
        u_int32_t priority;     /* priority for paging out      */
} agp_unbind;
.Ed
.El
.Sh FILES
.Bl -tag -width /dev/agpgart -compact
.It Pa /dev/agp?
AGP GART device special files
.It Pa /dev/agpgart
AGP GART device special file
.El
.Sh EXAMPLES
This short code fragment is an example of opening the AGP device
and performing some basic operations:
.Bd -literal
#include \*[Lt]sys/types.h\*[Gt]
#include \*[Lt]sys/ioctl.h\*[Gt]
#include \*[Lt]sys/agpio.h\*[Gt]
#include \*[Lt]fcntl.h\*[Gt]
#include \*[Lt]err.h\*[Gt]

int
main(int argc, char **argv)
{
	int fd;
	agp_info info;
	agp_allocate alloc;
	agp_setup setup;
	agp_bind bind;
	agp_unbind unbind;

	fd = open("/dev/agp0", O_RDWR);
	if (fd \*[Lt] 0)
		err(1, "open");

	if (ioctl(fd, AGPIOC_INFO, \*[Am]info) \*[Lt] 0)
		err(2, "ioctl AGPIOC_INFO");

	printf("version:	%u.%u\\n", info.version.major,
	    info.version.minor);

	printf("id:		%x\\n", info.bridge_id);
	printf("mode:		%x\\n", info.agp_mode);
	printf("base:		%x\\n", info.aper_base);
	printf("size:		%uM\\n", info.aper_size);
	printf("total mem:	%u\\n", info.pg_total);
	printf("system mem:	%u\\n", info.pg_system);
	printf("used mem:	%u\\n\\n", info.pg_used);

	setup.agp_mode = info.agp_mode;

	if (ioctl(fd, AGPIOC_SETUP, \*[Am]setup) \*[Lt] 0)
		err(3, "ioctl AGPIOC_SETUP");

	if (ioctl(fd, AGPIOC_ACQUIRE, 0) \*[Lt] 0)
		err(3, "ioctl AGPIOC_ACQUIRE");

	alloc.type = 0;
	alloc.pg_count = 64;

	if (ioctl(fd, AGPIOC_ALLOCATE, \*[Am]alloc) \*[Lt] 0)
		err(4, "ioctl AGPIOC_ALLOCATE");

	printf("alloc key %d, paddr %x\\n", alloc.key, alloc.physical);
	if (ioctl(fd, AGPIOC_INFO, \*[Am]info) \*[Lt] 0)
		err(5, "ioctl AGPIOC_INFO");

	bind.key = alloc.key;
	bind.pg_start = 0x1000;

	if (ioctl(fd, AGPIOC_BIND, \*[Am]bind) \*[Lt] 0)
		err(6, "ioctl AGPIOC_BIND");

	printf("used mem now:	%u\\n\\n", info.pg_used);

	unbind.key = alloc.key;
	unbind.priority = 0;

	if (ioctl(fd, AGPIOC_UNBIND, \*[Am]unbind) \*[Lt] 0)
		err(6, "ioctl AGPIOC_BIND");

	if (ioctl(fd, AGPIOC_DEALLOCATE, \*[Am]alloc.key) \*[Lt] 0)
		err(6, "ioctl AGPIOC_DEALLOCATE");

	if (ioctl(fd, AGPIOC_RELEASE, 0) \*[Lt] 0)
		err(7, "ioctl AGPIOC_RELEASE");

	close(fd);

	printf("agp test successful\\n");

	return 0;
}
.Ed
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr pci 4
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 4.1 .
It was adopted in
.Nx 1.6 .