/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
#ifndef _UAPI_ASM_GENERIC_IOCTL_H
#define _UAPI_ASM_GENERIC_IOCTL_H

/* ioctl command encoding: 32 bits total, command in lower 16 bits,
 * size of the parameter structure in the lower 14 bits of the
 * upper 16 bits.
 * Encoding the size of the parameter structure in the ioctl request
 * is useful for catching programs compiled with old versions
 * and to avoid overwriting user space outside the user buffer area.
 * The highest 2 bits are reserved for indicating the ``access mode''.
 * NOTE: This limits the max parameter size to 16kB -1 !
 */

/*
 * The following is for compatibility across the various Linux
 * platforms.  The generic ioctl numbering scheme doesn't really enforce
 * a type field.  De facto, however, the top 8 bits of the lower 16
 * bits are indeed used as a type field, so we might just as well make
 * this explicit here.  Please be sure to use the decoding macros
 * below from now on.
 */
#define _IOC_NRBITS 8
#define _IOC_TYPEBITS 8

/*
 * Let any architecture override either of the following before
 * including this file.
 */

#ifndef _IOC_SIZEBITS
#define _IOC_SIZEBITS 14
#endif

#ifndef _IOC_DIRBITS
#define _IOC_DIRBITS 2
#endif

#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, which any architecture can choose to override
 * before including this file.
 *
 * NOTE: _IOC_WRITE means userland is writing and kernel is
 * reading. _IOC_READ means userland is reading and kernel is writing.
 */

#ifndef _IOC_NONE
#define _IOC_NONE 0U
#endif

#ifndef _IOC_WRITE
#define _IOC_WRITE 1U
#endif

#ifndef _IOC_READ
#define _IOC_READ 2U
#endif

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

#ifndef __KERNEL__
#define _IOC_TYPECHECK(t) (sizeof(t))
#endif

/*
 * Used to create numbers.
 *
 * NOTE: _IOW means userland is writing and kernel is reading. _IOR
 * means userland is reading and kernel is writing.
 */
#define _IO(type, nr) _IOC(_IOC_NONE, (type), (nr), 0)
#define _IOR(type, nr, size) \
    _IOC(_IOC_READ, (type), (nr), (_IOC_TYPECHECK(size)))
#define _IOW(type, nr, size) \
    _IOC(_IOC_WRITE, (type), (nr), (_IOC_TYPECHECK(size)))
#define _IOWR(type, nr, size) \
    _IOC(_IOC_READ | _IOC_WRITE, (type), (nr), (_IOC_TYPECHECK(size)))
#define _IOR_BAD(type, nr, size) _IOC(_IOC_READ, (type), (nr), sizeof(size))
#define _IOW_BAD(type, nr, size) _IOC(_IOC_WRITE, (type), (nr), sizeof(size))
#define _IOWR_BAD(type, nr, size) \
    _IOC(_IOC_READ | _IOC_WRITE, (type), (nr), sizeof(size))

/* used to decode ioctl numbers.. */
#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)

/* ...and for the drivers/sound files... */

#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
#define IOC_INOUT ((_IOC_WRITE | _IOC_READ) << _IOC_DIRSHIFT)
#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)

#endif /* _UAPI_ASM_GENERIC_IOCTL_H */
