MMCGETDISCINFO
error = ioctl(dev_fd, MMCGETDISCINFO, &mmc_discinfo);
case MMCGETDISCINFO:
error = VOP_IOCTL(devvp, MMCGETDISCINFO, di, FKIOCTL, NOCRED);
error = bdev_ioctl(dev, MMCGETDISCINFO, &di, FKIOCTL, curlwp);