agpgart_io(7I) Ioctl Requests agpgart_io(7I)NAMEagpgart_io - Solaris agpgart driver I/O control operations
SYNOPSIS
#include <sys/agpgart.h>
DESCRIPTION
The Accelerated Graphics Port (AGP) is a PCI bus technology enhancement
that improves 3D graphics performance by using low-cost system memory.
AGP chipsets use the Graphics Address Remapping Table (GART) to map
discontiguous system memory into a contiguous PCI memory range (known
as the AGP Aperture), enabling the graphics card to utilize the mapped
aperture range as video memory.
The agpgart driver creates a pseudo device node at /dev/agpgart and
provides a set of ioctls for managing allocation/deallocation of sys‐
tem memory, setting mappings between system memory and aperture range,
and setting up AGP devices. The agpgart driver manages both pseudo and
real device nodes, but to initiate AGP-related operations you operate
only on the /dev/agpgart pseudo device node. To do this, open /dev/agp‐
gart. The macro defined for the pseudo device node name is:
#define AGP_DEVICE "/dev/agpgart"
The agpgart_io driver implementation is AGP architecture-dependent and
cannot be made generic. Currently, the agpgart_io driver only supports
specific AGP systems. To determine if a system is supported, run an
open(2) system call on the AGP_DEVICE node. (Note that open(2) fails
if a system is not supported). After the AGP_DEVICE is opened, you can
use kstat(1M) to read the system architecture type.
In addition to AGP system support, the agpgart ioctls can also be used
on Intel integrated graphics devices (IGD). IGD devices usually have no
dedicated video memory and must use system memory as video memory. IGD
devices contain translation tables (referred to as GTT tables) that are
similar to the GART translation table for address mapping purposes.
Processes must open the agpgart_io driver utilizing a GRAPHICS_ACCESS
privilege. Then all the ioctls can be called by this processes with
the saved file descriptor. With the exception of AGPIOC_INFO, the
AGPIOC_ACQUIRE ioctl must be called before any other ioctl. Once a
process has acquired GART, it cannot be acquired by another process
until the former process calls AGPIOC_RELEASE.
If the AGP_DEVICE fails to open, it may be due to one of the following
reasons:
EAGAIN
GART table allocation failed.
EIO
Internal hardware initialization failed.
ENXIO
Getting device soft state error. (This is unlikely to happen.)
EPERM
Without enough privilege.
IOCTLS
With the exception of GPIOC_INFO, all ioctls shown in this section are
protected by GRAPHICS_ACCESS privilege. (Only processes with GRAPH‐
ICS_ACCESS privilege in its effective set can access the privileged
ioctls).
Common ioctl error codes are shown below. (Additional error codes may
be displayed by individual ioctls.)
ENXIO
Ioctl command not supported or getting device soft state error.
EPERM
Process not privileged.
AGPIOC_INFO
Get system wide AGP or IGD hardware information. This command can
be called by any process from user or kernel context.
The argument is a pointer to agp_info_t structure.
typedef struct _agp_info {
agp_version_t agpi_version; /* OUT: AGP version supported */
uint32_t agpi_devid; /* OUT: bridge vendor + device */
uint32_t agpi_mode; /* OUT: mode of bridge */
ulong_t agpi_aperbase; /* OUT: base of aperture */
size_t agpi_apersize; /* OUT: aperture size in MB */
uint32_t agpi_pgtotal; /* OUT: max aperture pages avail. */
uint32_t agpi_pgsystem; /* OUT: same as pg_total */
uint32_t agpi_pgused; /* OUT: no. of currently used pages */
} agp_info_t;
agpi_version The version of AGP protocol the bridge device is
compatible with, for example, major 3 and minor 0
means AGP version 3.0.
typedef struct _agp_version {
uint16_t agpv_major;
uint16_t agpv_minor;
} agp_version_t;
agpi_devid AGP bridge vendor and device ID.
agpi_mode Current AGP mode, read from AGP status register of
target device. The main bits are defined as below.
/* AGP status register bits definition */
#define AGPSTAT_RQ_MASK 0xff000000
#define AGPSTAT_SBA (0x1 << 9)
#define AGPSTAT_OVER4G (0x1 << 5)
#define AGPSTAT_FW (0x1 << 4)
#define AGPSTAT_RATE_MASK 0x7
/* AGP 3.0 only bits */
#define AGPSTAT_ARQSZ_MASK (0x7 << 13)
#define AGPSTAT_CAL_MASK (0x7 << 10)
#define AGPSTAT_GART64B (0x1 << 7)
#define AGPSTAT_MODE3 (0x1 << 3)
/* rate for 2.0 mode */
#define AGP2_RATE_1X 0x1
#define AGP2_RATE_2X 0x2
#define AGP2_RATE_4X 0x4
/* rate for 3.0 mode */
#define AGP3_RATE_4X 0x1
#define AGP3_RATE_8X 0x2
agpi_aperbase The base address of aperture in PCI memory space.
agpi_apersize The size of the aperture in megabytes.
agpi_pgtotal Represents the maximum memory
pages the system can allocate
according to aperture size and
system memory size (which may differ
from the maximum locked memory a process
can have. The latter is subject
to the memory resource limit imposed
by the resource_controls(5) for each
project(4)):
project.max-device-locked-memory
This value can be modified through system
utilities like prctl(1).
agpi_pgsystem Same as pg_total.
agpi_pgused System pages already allocated by the driver.
Return Values:
EFAULT Argument copy out error
EINVAL Command invalid
0 Success
AGPIOC_ACQUIRE
Acquire control of GART. With the exception of AGPIOC_INFO, a
process must acquire GART before can it call other agpgart ioctl
commands. Additionally, only processes with GRAPHICS_ACCESS privi‐
lege may access this ioctl. In the current agpgart implementation,
GART access is exclusive, meaning that only one process can perform
GART operations at a time. To release control over GART, call
AGPIOC_RELEASE. This command can be called from user or kernel con‐
text.
The argument should be NULL.
Return values:
EBUSY GART has been acquired
0 Success.
AGPIOC_RELEASE
Release GART control. If a process releases GART control, it cannot
perform additional GART operations until GART is reacquired. Note
that this command does not free allocated memory or clear GART
entries. (All clear jobs are done by direct calls or by closing the
device). When a process exits without making this ioctl, the final
close(2) performs this automatically. This command can be called
from user or kernel context.
The argument should be NULL.
Return values:
EPERM Not owner of GART.
0 Success.
AGPIOC_SETUP
Setup AGPCMD register. An AGPCMD register resides in both the AGP
master and target devices. The AGPCMD register controls the working
mode of the AGP master and target devices. Each device must be
configured using the same mode. This command can be called from
user or kernel context.
The argument is a pointer to agp_setup_t structure:
typedef struct _agp_setup {
uint32_t agps_mode; /* IN: value to be set for AGPCMD */
} agp_setup_t;
agps_mode Specifying the mode to be set. Each bit of the value may have
a specific meaning, please refer to AGP 2.0/3.0 specification
or hardware datasheets for details.
/* AGP command register bits definition */
#define AGPCMD_RQ_MASK 0xff000000
#define AGPCMD_SBAEN (0x1 << 9)
#define AGPCMD_AGPEN (0x1 << 8)
#define AGPCMD_OVER4GEN (0x1 << 5)
#define AGPCMD_FWEN (0x1 << 4)
#define AGPCMD_RATE_MASK 0x7
/* AGP 3.0 only bits */
#define AGP3_CMD_ARQSZ_MASK (0x7 << 13)
#define AGP3_CMD_CAL_MASK (0x7 << 10)
#define AGP3_CMD_GART64BEN (0x1 << 7)
The final values set to the AGPCMD register of the master/target
devices are decided by the agps_mode value and AGPSTAT of the mas‐
ter and target devices.
Return Values:
EPERM Not owner of GART.
EFAULT Argument copy in error.
EINVAL Command invalid for non-AGP system.
EIO Hardware setup error.
0 Success.
AGPIOC_ALLOCATE
Allocate system memory for graphics device. This command returns a
unique ID which can be used in subsequent operations to represent
the allocated memory. The memory is made up of discontiguous physi‐
cal pages. In rare cases, special memory types may be required. The
allocated memory must be bound to the GART table before it can be
used by graphics device. Graphics applications can also mmap(2) the
memory to userland for data storing. Memory should be freed when it
is no longer used by calling AGPIOC_DEALLOCATE or simply by closing
the device. This command can be called from user or kernel context.
The argument is a pointer to agp_allocate_t structure.
typedef struct _agp_allocate {
int32_t agpa_key; /* OUT:ID of allocated memory */
uint32_t agpa_pgcount;/* IN: no. of pages to be allocated */
uint32_t agpa_type;/* IN: type of memory to be allocated */
uint32_t agpa_physical; /* OUT: reserved */
} agp_allocate_t;
agpa_key Unique ID of the allocated memory.
agpa_pgcount Number of pages to be allocated. The driver
currently supports only 4K pages. The value
cannot exceed the agpi_pgtotal value returned
by AGPIOC_INFO ioct and is subject to the
limit of project.max-device-locked-memory. If
the memory needed is larger than the resource
limit but not larger than agpi_pgtotal, use
prctl(1) or other system utilities to change
the default value of memory resource limit
beforehand.
agpa_type Type of memory to be allocated. The valid
value of agpa_type should be AGP_NORMAL. It is
defined as:
#define AGP_NORMAL 0
Above, AGP_NORMAL represents the discontiguous
non-cachable physical memory which doesn't
consume kernel virtual space but can be mapped
to user space by mmap(2). This command may
support more type values in the future.
agpa_physical Reserved for special uses. In normal opera‐
tions, the value is undefined.
Return Values:
EPERM Not owner of GART.
EINVAL Argument not valid.
EFAULT Argument copy in/out error.
ENOMEM Memory allocation error.
0 Success.
AGPIOC_DEALLOCATE Deallocate the memory identified by a key
assigned in a previous allocation. If the mem‐
ory isn't unbound from GART, this command
unbinds it automatically. The memory should no
longer be used and those still in mapping to
userland cannot be deallocated. Always call
AGPIOC_DEALLOCATE explicitly (instead of deal‐
locating implicitly by closing the device),
as the system won't carry out the job until
the last reference to the device file is
dropped. This command from user or kernel con‐
text.
The input argument is a key of type int32_t,
no output argument.
Return Values:
EPERM Not owner of GART.
EINVAL Key not valid or memory in use.
0 Success.
AGPIOC_BIND Bind allocated memory. This command binds
the allocated memory identified by a key to
a specific offset of the GART table, which
enables GART to translate the aperture
range at the offset to system memory. Each
GART entry represents one physical page. If
the GART range is previously bound to other
system memory, it returns an error. Once the
memory is bound, it cannot be bound to other
offsets unless it is unbound. To unbind the
memory, call AGPIOC_UNBIND or deallocate the
memory. This command can be called from user
or kernel context.
The argument is a pointer to agp_bind_t structure:
typedef struct _agp_bind {
int32_t agpb_key; /* IN: ID of memory to be bound */
uint32_t agpb_pgstart; /* IN: offset in aperture */
} agp_bind_t;
agpb_key The unique ID of the mem‐
ory to be bound, which is
previously allocated by
calling AGPIOC_ALLOCATE.
agpb_pgstart The starting page offset
to be bound in aperture
space.
Return Values:
EPERM Not owner of GART.
EFAULT Argument copy in error.
EINVAL Argument not valid.
EIO Binding to the GTT table
of IGD devices failed.
0 Success.
AGPIOC_UNBIND Unbind memory identified by a key from the
GART. This command clears the corresponding
entries in the GART table. Only the memory not
in mapping to userland is allowed to be
unbound.
This ioctl command can be called from user or
kernel context.
The argument is a pointer to agp_unbind_t structure.
typedef struct _agp_unbind {
int32_t agpu_key; /* IN: key of memory to be unbound*/
uint32_t agpu_pri; /* Not used: for compat. with Xorg */
} agp_unbind_t;
agpu_key Unique ID of the memory to
be unbound which was pre‐
viously bound by calling
AGPIOC_BIND.
agpu_pri Reserved for compatibility
with X.org/XFree86, not
used.
Return Values:
EPERM Not owner of GART.
EFAULT Argument copy in error.
EINVAL Argument not valid or mem‐
ory in use.
EIO Unbinding from the GTT ta‐
ble of IGD devices failed.
0 Success
EXAMPLE
Below is an sample program showing how agpgart ioctls can be used:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h
#include <sys/ioccom.h>
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/agpgart.h>
#define AGP_PAGE_SIZE 4096
int main(int argc, char *argv[])
{
int fd, ret;
agp_allocate_t alloc;
agp_bind_t bindinfo;
agp_info_t agpinfo;
agp_setup_t modesetup;
int *p = NULL;
off_t mapoff;
size_t maplen;
if((fd = open(AGP_DEVICE, O_RDWR))== -1) {
printf("open AGP_DEVICE error with %d\n", errno);\
exit(-1);
}
printf("device opened\n");
ret = ioctl(fd, AGPIOC_INFO, &agpinfo);
if(ret == -1) {
printf("Get info error %d0, errno);
exit(-1);
}
printf("AGPSTAT is %x\n", agpinfo.agpi_mode);
printf("APBASE is %x\n", agpinfo.agpi_aperbase);
printf("APSIZE is %dMB\n", agpinfo.agpi_apersize);
printf("pg_total is %d\n", agpinfo.agpi_pgtotal);
ret = ioctl(fd, AGPIOC_ACQUIRE);
if(ret == -1) {
printf(" Acquire GART error %d\n", errno);
exit(-1);
}
modesetup.agps_mode = agpinfo.agpi_mode;
ret = ioctl(fd, AGPIOC_SETUP, &modesetup);
if(ret == -1) {
printf("set up AGP mode error\n", errno);
exit(-1);
}
printf("Please input the number of pages you want to allocate\n");
scanf("%d", &alloc.agpa_pgcount);
alloc.agpa_type = AGP_NORMAL;
ret = ioctl(fd, AGPIOC_ALLOCATE, &alloc);
if(ret == -1) {
printf("Allocate memory error %d\n", errno);
exit(-1);
}
printf("Please input the aperture page offset to bind\n");
scanf("%d", &bindinfo.agpb_pgstart);
bindinfo.agpb_key = alloc.agpa_key;
ret = ioctl(fd, AGPIOC_BIND, &bindinfo);
if(ret == -1) {
printf("Bind error %d\n", errno);
exit(-1);
}
printf("Bind successful\n");
/*
* Now gart aperture space from (bindinfo.agpb_pgstart) to
* (bindinfo.agpb_pgstart + alloc.agpa_pgcount) can be used for
* AGP graphics transactions
*/
...
/*
* mmap can allow user processes to store graphics data
* to the aperture space
*/
maplen = alloc.agpa_pgcount * AGP_PAGE_SIZE;
mapoff = bindinfo.agpb_pgstart * AGP_PAGE_SIZE;
p = (int *)mmap((caddr_t)0, maplen, (PROT_READ | PROT_WRITE),
MAP_SHARED, fd, mapoff);
if (p == MAP_FAILED) {
printf("Mmap error %d\n", errno);
exit(-1);
}
printf("Mmap successful\n");
...
/*
* When user processes finish access to the aperture space,
* unmap the memory range
*/
munmap((void *)p, maplen);
...
/*
* After finishing AGP transactions, the resources can be freed
* step by step or simply by close device.
*/
ret = ioctl(fd, AGPIOC_DEALLOCATE, alloc.agpa_key);
if(ret == -1) {
printf(" Deallocate memory error %d\n", errno);
exit(-1);
}
ret = ioctl(fd, AGPIOC_RELEASE);
if(ret == -1) {
printf(" Release GART error %d\n", errno);
exit(-1);
}
close(fd);
}
FILES
/dev/agpgart
Symbolic link to the pseudo agpgart device.
/platform/i86pc/kernel/drv/agpgart
agpgart pseudo driver.
/platform/i86pc/kernel/drv/agpgart.conf
Driver configuration file.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬───────────────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼───────────────────────────────────────┤
│Architecture │ X86 │
├────────────────────┼───────────────────────────────────────┤
│Availability │ driver/graphics/agpgart, │
│ │ driver/graphics/agpgarth │
├────────────────────┼───────────────────────────────────────┤
│Interface Stability │ Uncommitted │
└────────────────────┴───────────────────────────────────────┘
SEE ALSOprctl(1), kstat(1M), close(2), ioctl(2), open(2), mmap(2), project(4),
privileges(5), attributes(5), resource_controls(5)SunOS 5.11 25 Sep 2008 agpgart_io(7I)
