.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\"
.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Gregory McGarry.
.\"
.\" Copyright (c) 2001 Yar Tikhiy
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
.\" are met:
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.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" $NetBSD: agp.4,v 1.10 2003/05/14 07:59:00 wiz Exp $
.\" $DragonFly: src/share/man/man4/agp.4,v 1.5 2007/09/12 09:26:32 hasso Exp $
.\"
.Dd September 12, 2007
.Dt AGP 4
.Os
.Sh NAME
.Nm agp
.Nd accelerated graphics port driver
.Sh SYNOPSIS
To compile this driver into the kernel,
place the following lines in your
kernel configuration file:
.Bd -ragged -offset indent
.Cd "device agp"
.Ed
.Pp
Alternatively, to load the driver as a
module at boot time, place the following line in
.Xr loader.conf 5 :
.Bd -literal -offset indent
agp_load="YES"
.Ed
.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, M1621 and M1671 host to AGP bridges
.It
AMD 751, 761 and 762 host to AGP bridges
.It
AMD 8151 AGP graphics tunnel
.It
ATI RS100, RS200, RS250 and RS300 AGP bridges
.It
Intel i810, i815, i830, 845, 852, 855, 865, 915, 945, 946 and 965
series SVGA controllers
.It
Intel 82443LX, 82443BX, 82443GX, i820, i840, i845, i845G, i850, i855,
i855GM, i860, i865, i875P, E7205 and E7505 host to AGP bridges
.It
Nvidia nForce, nForce2 and nForce3 AGP controllers
.It
SiS 530, 540, 550, 620, 630, 645, 645DX, 648, 650, 651, 655, 661, 730,
735, 740, 741, 745, 746, 755, 760 and 5591 host to AGP bridges
.It
ULi M1689 AGP controller
.It
VIa 3238, 3296, 82C597, 82C598, 82C691, 82C694X, 82C8363, 8235, 8237,
8361, 8367, 8371, 8377, 8380, 8385, 8501, 8601, 862x, 8633, 8653, 8703,
8753, 8754, 8763, 8783, KT880, K8T800Pro, PM800, PM880, PN800, PN880,
PT880, XM266 and XN266 host to PCI bridges
.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 performed on
.Pa /dev/agpgart .
All calls and related structures are defined in
.In sys/agpio.h .
The calls supported are:
.Bl -tag -width indent
.It Dv AGPIOC_INFO
Returns state of the
.Nm
system.
The result is a pointer to the following structure:
.Bd -literal
typedef struct _agp_info {
        agp_version version;    /* version of the driver       */
        uint32_t bridge_id;     /* bridge vendor/device        */
        uint32_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 control of the AGP chipset for use by this client.
Returns
.Er EBUSY
if the AGP chipset is already acquired by another client.
.It Dv AGPIOC_RELEASE
Release control of the AGP chipset.
This does not unbind or free any allocated memory, which is the
responsibility of the client to handle if necessary.
.It Dv AGPIOC_SETUP
Enable the AGP hardware with the relevant mode.
This
.Xr ioctl 2
takes the following structure:
.Bd -literal
typedef struct _agp_setup {
        uint32_t agp_mode;     /* mode info of bridge          */
} agp_setup;
.Ed
.Pp
The mode bits are defined in
.In sys/agpio.h .
.It Dv AGPIOC_ALLOCATE
Allocate physical memory suitable for mapping into the AGP aperture.
This
.Xr ioctl 2
takes the following structure:
.Bd -literal
typedef struct _agp_allocate {
        int key;               /* tag of allocation            */
        size_t pg_count;       /* number of pages              */
        uint32_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
.Pp
Returns a handle to the allocated memory.
.It Dv AGPIOC_DEALLOCATE
Free the previously allocated memory associated with the handle passed.
.It Dv AGPIOC_BIND
Bind the allocated memory at given offset with the AGP aperture.
Returns
.Er EINVAL
if the memory is already bound or the offset is not at AGP page boundary.
This
.Xr ioctl 2
takes the following structure:
.Bd -literal
typedef struct _agp_bind {
        int key;               /* tag of allocation            */
        off_t pg_start;        /* starting page to populate    */
} agp_bind;
.Ed
.Pp
The tag of allocation is the handle returned by
.Dv AGPIOC_ALLOCATE .
.It Dv AGPIOC_UNBIND
Unbind memory from the AGP aperture.
Returns
.Er EINVAL
if the memory is not bound.
This
.Xr ioctl 2
takes the following structure:
.Bd -literal
typedef struct _agp_unbind {
        int key;               /* tag of allocation            */
        uint32_t priority;     /* priority for paging out      */
} agp_unbind;
.Ed
.El
.Sh FILES
.Bl -tag -width ".Pa /dev/agpgart" -compact
.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]stdio.h\*[Gt]
#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/agpgart", 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
.Sh HISTORY
The
.Nm
driver first appeared in
.Fx 4.1 .