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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#ifndef _ALPHA_IOCTL_H
2#define _ALPHA_IOCTL_H
3
4/*
5 * The original linux ioctl numbering scheme was just a general
6 * "anything goes" setup, where more or less random numbers were
7 * assigned. Sorry, I was clueless when I started out on this.
8 *
9 * On the alpha, we'll try to clean it up a bit, using a more sane
10 * ioctl numbering, and also trying to be compatible with OSF/1 in
11 * the process. I'd like to clean it up for the i386 as well, but
12 * it's so painful recognizing both the new and the old numbers..
13 */
14
15#define _IOC_NRBITS 8
16#define _IOC_TYPEBITS 8
17#define _IOC_SIZEBITS 13
18#define _IOC_DIRBITS 3
19
20#define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
21#define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
22#define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
23#define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
24
25#define _IOC_NRSHIFT 0
26#define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
27#define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
28#define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
29
30/*
31 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
32 * And this turns out useful to catch old ioctl numbers in header
33 * files for us.
34 */
35#define _IOC_NONE 1U
36#define _IOC_READ 2U
37#define _IOC_WRITE 4U
38
39#define _IOC(dir,type,nr,size) \
40 ((unsigned int) \
41 (((dir) << _IOC_DIRSHIFT) | \
42 ((type) << _IOC_TYPESHIFT) | \
43 ((nr) << _IOC_NRSHIFT) | \
44 ((size) << _IOC_SIZESHIFT)))
45
46/* used to create numbers */
47#define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
48#define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
49#define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
50#define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
51
52/* used to decode them.. */
53#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
54#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
55#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
56#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
57
58/* ...and for the drivers/sound files... */
59
60#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
61#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
62#define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
63#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
64#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
65
66#endif /* _ALPHA_IOCTL_H */