1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License.  See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1995, 96, 99, 2001 Ralf Baechle
7 */
8#ifndef _ASM_IOCTL_H
9#define _ASM_IOCTL_H
10
11/*
12 * The original linux ioctl numbering scheme was just a general
13 * "anything goes" setup, where more or less random numbers were
14 * assigned.  Sorry, I was clueless when I started out on this.
15 *
16 * On the alpha, we'll try to clean it up a bit, using a more sane
17 * ioctl numbering, and also trying to be compatible with OSF/1 in
18 * the process. I'd like to clean it up for the i386 as well, but
19 * it's so painful recognizing both the new and the old numbers..
20 *
21 * The same applies for for the MIPS ABI; in fact even the macros
22 * from Linux/Alpha fit almost perfectly.
23 */
24
25#define _IOC_NRBITS	8
26#define _IOC_TYPEBITS	8
27#define _IOC_SIZEBITS	13
28#define _IOC_DIRBITS	3
29
30#define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
31#define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
32#define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
33#define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
34
35#define _IOC_NRSHIFT	0
36#define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
37#define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
38#define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
39
40/*
41 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
42 * And this turns out useful to catch old ioctl numbers in header
43 * files for us.
44 */
45#define _IOC_NONE	1U
46#define _IOC_READ	2U
47#define _IOC_WRITE	4U
48
49/*
50 * The following are included for compatibility
51 */
52#define _IOC_VOID	0x20000000
53#define _IOC_OUT	0x40000000
54#define _IOC_IN		0x80000000
55#define _IOC_INOUT	(IOC_IN|IOC_OUT)
56
57#define _IOC(dir,type,nr,size) \
58	(((dir)  << _IOC_DIRSHIFT) | \
59	 ((type) << _IOC_TYPESHIFT) | \
60	 ((nr)   << _IOC_NRSHIFT) | \
61	 ((size) << _IOC_SIZESHIFT))
62
63/* provoke compile error for invalid uses of size argument */
64extern unsigned int __invalid_size_argument_for_IOC;
65#define _IOC_TYPECHECK(t) \
66	((sizeof(t) == sizeof(t[1]) && \
67	  sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
68	  sizeof(t) : __invalid_size_argument_for_IOC)
69
70/* used to create numbers */
71#define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
72#define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
73#define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
74#define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
75#define _IOR_BAD(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
76#define _IOW_BAD(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
77#define _IOWR_BAD(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
78
79
80/* used to decode them.. */
81#define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
82#define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
83#define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
84#define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
85
86/* ...and for the drivers/sound files... */
87
88#define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
89#define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
90#define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
91#define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
92#define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
93
94#endif /* _ASM_IOCTL_H */
95