blob: cba641a6ce09a5b674081820a14767c507ff1bd4 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 * We to additionally limit parameters to a maximum 255 bytes.
42 */
43#define _IOC_SLMASK 0xff
44
45/*
46 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
47 * And this turns out useful to catch old ioctl numbers in header
48 * files for us.
49 */
50#define _IOC_NONE 1U
51#define _IOC_READ 2U
52#define _IOC_WRITE 4U
53
54/*
55 * The following are included for compatibility
56 */
57#define _IOC_VOID 0x20000000
58#define _IOC_OUT 0x40000000
59#define _IOC_IN 0x80000000
60#define _IOC_INOUT (IOC_IN|IOC_OUT)
61
62#define _IOC(dir,type,nr,size) \
63 (((dir) << _IOC_DIRSHIFT) | \
64 ((type) << _IOC_TYPESHIFT) | \
65 ((nr) << _IOC_NRSHIFT) | \
66 ((size) << _IOC_SIZESHIFT))
67
68/* provoke compile error for invalid uses of size argument */
69extern unsigned int __invalid_size_argument_for_IOC;
70#define _IOC_TYPECHECK(t) \
71 ((sizeof(t) == sizeof(t[1]) && \
72 sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
73 sizeof(t) : __invalid_size_argument_for_IOC)
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
85/* used to decode them.. */
86#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
87#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
88#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
89#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
90
91/* ...and for the drivers/sound files... */
92
93#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
94#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
95#define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
96#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
97#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
98
99#endif /* _ASM_IOCTL_H */