1/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2#ifndef _ALPHA_IOCTL_H
3#define _ALPHA_IOCTL_H
4
5/*
6 * The original linux ioctl numbering scheme was just a general
7 * "anything goes" setup, where more or less random numbers were
8 * assigned.  Sorry, I was clueless when I started out on this.
9 *
10 * On the alpha, we'll try to clean it up a bit, using a more sane
11 * ioctl numbering, and also trying to be compatible with OSF/1 in
12 * the process. I'd like to clean it up for the i386 as well, but
13 * it's so painful recognizing both the new and the old numbers..
14 */
15
16#define _IOC_NRBITS	8
17#define _IOC_TYPEBITS	8
18#define _IOC_SIZEBITS	13
19#define _IOC_DIRBITS	3
20
21#define _IOC_NRMASK	((1 << _IOC_NRBITS)-1)
22#define _IOC_TYPEMASK	((1 << _IOC_TYPEBITS)-1)
23#define _IOC_SIZEMASK	((1 << _IOC_SIZEBITS)-1)
24#define _IOC_DIRMASK	((1 << _IOC_DIRBITS)-1)
25
26#define _IOC_NRSHIFT	0
27#define _IOC_TYPESHIFT	(_IOC_NRSHIFT+_IOC_NRBITS)
28#define _IOC_SIZESHIFT	(_IOC_TYPESHIFT+_IOC_TYPEBITS)
29#define _IOC_DIRSHIFT	(_IOC_SIZESHIFT+_IOC_SIZEBITS)
30
31/*
32 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
33 * And this turns out useful to catch old ioctl numbers in header
34 * files for us.
35 */
36#define _IOC_NONE	1U
37#define _IOC_READ	2U
38#define _IOC_WRITE	4U
39
40#define _IOC(dir,type,nr,size)			\
41	((unsigned int)				\
42	 (((dir)  << _IOC_DIRSHIFT) |		\
43	  ((type) << _IOC_TYPESHIFT) |		\
44	  ((nr)   << _IOC_NRSHIFT) |		\
45	  ((size) << _IOC_SIZESHIFT)))
46
47/* used to create numbers */
48#define _IO(type,nr)		_IOC(_IOC_NONE,(type),(nr),0)
49#define _IOR(type,nr,size)	_IOC(_IOC_READ,(type),(nr),sizeof(size))
50#define _IOW(type,nr,size)	_IOC(_IOC_WRITE,(type),(nr),sizeof(size))
51#define _IOWR(type,nr,size)	_IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
52
53/* used to decode them.. */
54#define _IOC_DIR(nr)		(((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
55#define _IOC_TYPE(nr)		(((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
56#define _IOC_NR(nr)		(((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
57#define _IOC_SIZE(nr)		(((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
58
59/* ...and for the drivers/sound files... */
60
61#define IOC_IN		(_IOC_WRITE << _IOC_DIRSHIFT)
62#define IOC_OUT		(_IOC_READ << _IOC_DIRSHIFT)
63#define IOC_INOUT	((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
64#define IOCSIZE_MASK	(_IOC_SIZEMASK << _IOC_SIZESHIFT)
65#define IOCSIZE_SHIFT	(_IOC_SIZESHIFT)
66
67#endif /* _ALPHA_IOCTL_H */
68