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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1/*
2 * include/asm-xtensa/ioctl.h
3 *
4 * This file is subject to the terms and conditions of the GNU General Public
5 * License. See the file "COPYING" in the main directory of this archive
6 * for more details.
7 *
8 * Copyright (C) 2003 - 2005 Tensilica Inc.
9 *
10 * Derived from "include/asm-i386/ioctl.h"
11 */
12
13#ifndef _XTENSA_IOCTL_H
14#define _XTENSA_IOCTL_H
15
16
17/* ioctl command encoding: 32 bits total, command in lower 16 bits,
18 * size of the parameter structure in the lower 14 bits of the
19 * upper 16 bits.
20 * Encoding the size of the parameter structure in the ioctl request
21 * is useful for catching programs compiled with old versions
22 * and to avoid overwriting user space outside the user buffer area.
23 * The highest 2 bits are reserved for indicating the ``access mode''.
24 * NOTE: This limits the max parameter size to 16kB -1 !
25 */
26
27/*
28 * The following is for compatibility across the various Linux
29 * platforms. The i386 ioctl numbering scheme doesn't really enforce
30 * a type field. De facto, however, the top 8 bits of the lower 16
31 * bits are indeed used as a type field, so we might just as well make
32 * this explicit here. Please be sure to use the decoding macros
33 * below from now on.
34 */
35#define _IOC_NRBITS 8
36#define _IOC_TYPEBITS 8
37#define _IOC_SIZEBITS 14
38#define _IOC_DIRBITS 2
39
40#define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
41#define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
42#define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
43#define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
44
45#define _IOC_NRSHIFT 0
46#define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
47#define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
48#define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
49
50/*
51 * Direction bits.
52 */
53#define _IOC_NONE 0U
54#define _IOC_WRITE 1U
55#define _IOC_READ 2U
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/* used to create numbers */
64#define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
65#define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
66#define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
67#define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
68
69/* used to decode ioctl numbers.. */
70#define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
71#define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
72#define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
73#define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
74
75/* ...and for the drivers/sound files... */
76
77#define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
78#define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
79#define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
80#define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
81#define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
82
83#endif