#include <assert.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include "drm.h"
#include "vgem_drm.h"
#include "libvgem.h"

int
drm_open_vgem(void)
{
	char *name;
	int i, fd;

	for (i = 0; i < 16; i++) {
		struct stat _stat;
		int ret;
		ret = asprintf(&name, "/sys/bus/platform/devices/vgem/drm/card%d", i);
		assert(ret != -1);

		if (stat(name, &_stat) == -1) {
			free(name);
			continue;
		}

		free(name);
		ret = asprintf(&name, "/dev/dri/card%d", i);
		assert(ret != -1);

		fd = open(name, O_RDWR);
		free(name);
		if (fd == -1) {
			perror("Couldn't open drm device read/write\n");
			return -1;
		}
		return fd;
	}
	fprintf(stderr, "failed to open any drm device. retry as root?\n");
	abort();
}

int
create_vgem_bo(int fd, size_t size)
{
	struct drm_mode_create_dumb create;
	int ret;

	if (size == 0)
		size = 4096;

	memset(&create, 0, sizeof(create));
	create.height = size;
	create.width = 1;
	create.bpp = 1;

	ret = drmIoctl(fd, DRM_IOCTL_MODE_CREATE_DUMB, &create);
	if (ret) {
		fprintf(stderr, "DRM_IOCTL_MODE_CREATE_DUMB, failed with "
				"%d\n", ret);
		abort();
	}

	assert(create.size == size);

	return create.handle;
}

void *
mmap_vgem_bo(int fd, int handle, size_t size)
{
	struct drm_mode_map_dumb mmap_arg;
	void *ptr;
	int ret;

	memset(&mmap_arg, 0, sizeof(mmap_arg));

	mmap_arg.handle = handle;

	ret = drmIoctl(fd, DRM_IOCTL_MODE_MAP_DUMB, &mmap_arg);
	assert(ret == 0);
	assert(mmap_arg.offset != 0);

	ptr = mmap(NULL, size, (PROT_READ|PROT_WRITE), MAP_PRIVATE, fd,
		   mmap_arg.offset);
	assert(ptr != MAP_FAILED);

	return ptr;
}