1#ifndef _UAPI_ASM_GENERIC_IOCTL_H
2#define _UAPI_ASM_GENERIC_IOCTL_H
3
4/* ioctl command encoding: 32 bits total, command in lower 16 bits,
5 * size of the parameter structure in the lower 14 bits of the
6 * upper 16 bits.
7 * Encoding the size of the parameter structure in the ioctl request
8 * is useful for catching programs compiled with old versions
9 * and to avoid overwriting user space outside the user buffer area.
10 * The highest 2 bits are reserved for indicating the ``access mode''.
11 * NOTE: This limits the max parameter size to 16kB -1 !
12 */
13
14/*
15 * The following is for compatibility across the various Linux
16 * platforms.  The generic ioctl numbering scheme doesn't really enforce
17 * a type field.  De facto, however, the top 8 bits of the lower 16
18 * bits are indeed used as a type field, so we might just as well make
19 * this explicit here.  Please be sure to use the decoding macros
20 * below from now on.
21 */
22#define _IOC_NRBITS	8
23#define _IOC_TYPEBITS	8
24
25/*
26 * Let any architecture override either of the following before
27 * including this file.
28 */
29
30#ifndef _IOC_SIZEBITS
31# define _IOC_SIZEBITS	14
32#endif
33
34#ifndef _IOC_DIRBITS
35# define _IOC_DIRBITS	2
36#endif
37
38#define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
39#define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
40#define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
41#define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
42
43#define _IOC_NRSHIFT	0
44#define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
45#define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
46#define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
47
48/*
49 * Direction bits, which any architecture can choose to override
50 * before including this file.
51 */
52
53#ifndef _IOC_NONE
54# define _IOC_NONE	0U
55#endif
56
57#ifndef _IOC_WRITE
58# define _IOC_WRITE	1U
59#endif
60
61#ifndef _IOC_READ
62# define _IOC_READ	2U
63#endif
64
65#define _IOC(dir,type,nr,size) \
66	(((dir)  << _IOC_DIRSHIFT) | \
67	 ((type) << _IOC_TYPESHIFT) | \
68	 ((nr)   << _IOC_NRSHIFT) | \
69	 ((size) << _IOC_SIZESHIFT))
70
71#ifndef __KERNEL__
72#define _IOC_TYPECHECK(t) (sizeof(t))
73#endif
74
75/* used to create numbers */
76#define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
77#define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
78#define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
79#define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
80#define _IOR_BAD(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
81#define _IOW_BAD(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
82#define _IOWR_BAD(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
83
84/* used to decode ioctl numbers.. */
85#define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
86#define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
87#define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
88#define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
89
90/* ...and for the drivers/sound files... */
91
92#define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
93#define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
94#define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
95#define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
96#define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
97
98#endif /* _UAPI_ASM_GENERIC_IOCTL_H */
99