1 /*
2 * include/asm-s390/ioctl.h
3 *
4 * S390 version
5 *
6 * Derived from "include/asm-i386/ioctl.h"
7 */
8
9 #ifndef _S390_IOCTL_H
10 #define _S390_IOCTL_H
11
12 /* ioctl command encoding: 32 bits total, command in lower 16 bits,
13 * size of the parameter structure in the lower 14 bits of the
14 * upper 16 bits.
15 * Encoding the size of the parameter structure in the ioctl request
16 * is useful for catching programs compiled with old versions
17 * and to avoid overwriting user space outside the user buffer area.
18 * The highest 2 bits are reserved for indicating the ``access mode''.
19 * NOTE: This limits the max parameter size to 16kB -1 !
20 */
21
22 /*
23 * The following is for compatibility across the various Linux
24 * platforms. The i386 ioctl numbering scheme doesn't really enforce
25 * a type field. De facto, however, the top 8 bits of the lower 16
26 * bits are indeed used as a type field, so we might just as well make
27 * this explicit here. Please be sure to use the decoding macros
28 * below from now on.
29 */
30 #define _IOC_NRBITS 8
31 #define _IOC_TYPEBITS 8
32 #define _IOC_SIZEBITS 14
33 #define _IOC_DIRBITS 2
34
35 #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
36 #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
37 #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
38 #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
39
40 #define _IOC_NRSHIFT 0
41 #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
42 #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
43 #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
44
45 /*
46 * Direction bits.
47 */
48 #define _IOC_NONE 0U
49 #define _IOC_WRITE 1U
50 #define _IOC_READ 2U
51
52 #define _IOC(dir,type,nr,size) \
53 (((dir) << _IOC_DIRSHIFT) | \
54 ((type) << _IOC_TYPESHIFT) | \
55 ((nr) << _IOC_NRSHIFT) | \
56 ((size) << _IOC_SIZESHIFT))
57
58 /* used to create numbers */
59 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
60 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
61 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
62 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
63
64 /* used to decode ioctl numbers.. */
65 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
66 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
67 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
68 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
69
70 /* ...and for the drivers/sound files... */
71
72 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
73 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
74 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
75 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
76 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
77
78 #endif /* _S390_IOCTL_H */
79
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