1 /*
2 * Linux ioctl() stuff.
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) 1995, 1996 by Ralf Baechle
9 */
10 #ifndef __ASM_MIPS_IOCTL_H
11 #define __ASM_MIPS_IOCTL_H
12
13 /*
14 * The original linux ioctl numbering scheme was just a general
15 * "anything goes" setup, where more or less random numbers were
16 * assigned. Sorry, I was clueless when I started out on this.
17 *
18 * On the alpha, we'll try to clean it up a bit, using a more sane
19 * ioctl numbering, and also trying to be compatible with OSF/1 in
20 * the process. I'd like to clean it up for the i386 as well, but
21 * it's so painful recognizing both the new and the old numbers..
22 *
23 * The same applies for for the MIPS ABI; in fact even the macros
24 * from Linux/Alpha fit almost perfectly.
25 */
26
27 #define _IOC_NRBITS 8
28 #define _IOC_TYPEBITS 8
29 #define _IOC_SIZEBITS 13
30 #define _IOC_DIRBITS 3
31
32 #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
33 #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
34 #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
35 #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
36
37 #define _IOC_NRSHIFT 0
38 #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
39 #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
40 #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
41
42 /*
43 * We to additionally limit parameters to a maximum 255 bytes.
44 */
45 #define _IOC_SLMASK 0xff
46
47 /*
48 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
49 * And this turns out useful to catch old ioctl numbers in header
50 * files for us.
51 */
52 #define _IOC_NONE 1U
53 #define _IOC_READ 2U
54 #define _IOC_WRITE 4U
55
56 /*
57 * The following are included for compatibility
58 */
59 #define _IOC_VOID 0x20000000
60 #define _IOC_OUT 0x40000000
61 #define _IOC_IN 0x80000000
62 #define _IOC_INOUT (IOC_IN|IOC_OUT)
63
64 #define _IOC(dir,type,nr,size) \
65 (((dir) << _IOC_DIRSHIFT) | \
66 ((type) << _IOC_TYPESHIFT) | \
67 ((nr) << _IOC_NRSHIFT) | \
68 (((size) & _IOC_SLMASK) << _IOC_SIZESHIFT))
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),sizeof(size))
73 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
74 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
75
76 /* used to decode them.. */
77 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
78 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
79 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
80 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
81
82 /* ...and for the drivers/sound files... */
83
84 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
85 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
86 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
87 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
88 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
89
90 #endif /* __ASM_MIPS_IOCTL_H */
91
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