/*
 * Copyright (C) 2023 Xiaomi Corperation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef __IOCTL_H__
#define __IOCTL_H__

#define _IOC_NRBITS 8
#define _IOC_TYPEBITS 8
#define _IOC_SIZEBITS 13
#define _IOC_DIRBITS 3

#define _IOC_NRMASK ((1 << _IOC_NRBITS) - 1)
#define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS) - 1)
#define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS) - 1)
#define _IOC_DIRMASK ((1 << _IOC_DIRBITS) - 1)

#define _IOC_NRSHIFT 0
#define _IOC_TYPESHIFT (_IOC_NRSHIFT + _IOC_NRBITS)
#define _IOC_SIZESHIFT (_IOC_TYPESHIFT + _IOC_TYPEBITS)
#define _IOC_DIRSHIFT (_IOC_SIZESHIFT + _IOC_SIZEBITS)

/*
 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
 * And this turns out useful to catch old ioctl numbers in header
 * files for us.
 */
#define _IOC_NONE 1U
#define _IOC_READ 2U
#define _IOC_WRITE 4U

#define __IOC(dir, type, nr, size) \
    ((unsigned int)(((dir) << _IOC_DIRSHIFT) | ((type) << _IOC_TYPESHIFT) | ((nr) << _IOC_NRSHIFT) | ((size) << _IOC_SIZESHIFT)))

/* used to create numbers */
#define _IO(type, nr) __IOC(_IOC_NONE, (type), (nr), 0)
#define _IOR(type, nr, size) __IOC(_IOC_READ, (type), (nr), sizeof(size))
#define _IOW(type, nr, size) __IOC(_IOC_WRITE, (type), (nr), sizeof(size))
#define _IOWR(type, nr, size) __IOC(_IOC_READ | _IOC_WRITE, (type), (nr), sizeof(size))

#endif /* __IOCTL_H__ */