1/*
2 * linux/ioctl.h for Linux by H.H. Bergman.
3 */
4
5#ifndef _ASMARM_IOCTL_H
6#define _ASMARM_IOCTL_H
7
8/* ioctl command encoding: 32 bits total, command in lower 16 bits,
9 * size of the parameter structure in the lower 14 bits of the
10 * upper 16 bits.
11 * Encoding the size of the parameter structure in the ioctl request
12 * is useful for catching programs compiled with old versions
13 * and to avoid overwriting user space outside the user buffer area.
14 * The highest 2 bits are reserved for indicating the ``access mode''.
15 * NOTE: This limits the max parameter size to 16kB -1 !
16 */
17
18/*
19 * The following is for compatibility across the various Linux
20 * platforms.  The i386 ioctl numbering scheme doesn't really enforce
21 * a type field.  De facto, however, the top 8 bits of the lower 16
22 * bits are indeed used as a type field, so we might just as well make
23 * this explicit here.  Please be sure to use the decoding macros
24 * below from now on.
25 */
26#define _IOC_NRBITS	8
27#define _IOC_TYPEBITS	8
28#define _IOC_SIZEBITS	14
29#define _IOC_DIRBITS	2
30
31#define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
32#define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
33#define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
34#define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
35
36#define _IOC_NRSHIFT	0
37#define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
38#define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
39#define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
40
41/*
42 * Direction bits.
43 */
44#define _IOC_NONE	0U
45#define _IOC_WRITE	1U
46#define _IOC_READ	2U
47
48#define _IOC(dir,type,nr,size) \
49	(((dir)  << _IOC_DIRSHIFT) | \
50	 ((type) << _IOC_TYPESHIFT) | \
51	 ((nr)   << _IOC_NRSHIFT) | \
52	 ((size) << _IOC_SIZESHIFT))
53
54/* used to create numbers */
55#define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
56#define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
57#define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
58#define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
59
60/* used to decode ioctl numbers.. */
61#define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
62#define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
63#define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
64#define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
65
66/* ...and for the drivers/sound files... */
67
68#define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
69#define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
70#define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
71#define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
72#define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
73
74#endif /* _ASMARM_IOCTL_H */
75