This short code fragment is an example of opening the AGP device and performing some basic operations:
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/agpio.h>
#include <fcntl.h>
#include <err.h>
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 < 0)
err(1, "open");
if (ioctl(fd, AGPIOC_INFO, &info) < 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, &setup) < 0)
err(3, "ioctl AGPIOC_SETUP");
if (ioctl(fd, AGPIOC_ACQUIRE, 0) < 0)
err(3, "ioctl AGPIOC_ACQUIRE");
alloc.type = 0;
alloc.pg_count = 64;
if (ioctl(fd, AGPIOC_ALLOCATE, &alloc) < 0)
err(4, "ioctl AGPIOC_ALLOCATE");
printf("alloc key %d, paddr %x\n", alloc.key, alloc.physical);
if (ioctl(fd, AGPIOC_INFO, &info) < 0)
err(5, "ioctl AGPIOC_INFO");
bind.key = alloc.key;
bind.pg_start = 0x1000;
if (ioctl(fd, AGPIOC_BIND, &bind) < 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, &unbind) < 0)
err(6, "ioctl AGPIOC_BIND");
if (ioctl(fd, AGPIOC_DEALLOCATE, &alloc.key) < 0)
err(6, "ioctl AGPIOC_DEALLOCATE");
if (ioctl(fd, AGPIOC_RELEASE, 0) < 0)
err(7, "ioctl AGPIOC_RELEASE");
close(fd);
printf("agp test successful\n");
return 0;
}