2 * linux/ioctl.h for Linux by H.H. Bergman.
5 #ifndef _ASMI386_IOCTL_H
6 #define _ASMI386_IOCTL_H
8 /* ioctl command encoding: 32 bits total, command in lower 16 bits,
9 * size of the parameter structure in the lower 14 bits of the
11 * Encoding the size of the parameter structure in the ioctl request
12 * is useful for catching programs compiled with old versions
13 * and to avoid overwriting user space outside the user buffer area.
14 * The highest 2 bits are reserved for indicating the ``access mode''.
15 * NOTE: This limits the max parameter size to 16kB -1 !
19 * The following is for compatibility across the various Linux
20 * platforms. The i386 ioctl numbering scheme doesn't really enforce
21 * a type field. De facto, however, the top 8 bits of the lower 16
22 * bits are indeed used as a type field, so we might just as well make
23 * this explicit here. Please be sure to use the decoding macros
34 #define _IOC_TYPEBITS 8
35 #define _IOC_SIZEBITS 14
36 #define _IOC_DIRBITS 2
38 #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
39 #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
40 #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
41 #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
43 #define _IOC_NRSHIFT 0
44 #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
45 #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
46 #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
55 #define _IOC(dir,type,nr,size) \
56 (((dir) << _IOC_DIRSHIFT) | \
57 ((type) << _IOC_TYPESHIFT) | \
58 ((nr) << _IOC_NRSHIFT) | \
59 ((size) << _IOC_SIZESHIFT))
61 /* used to create numbers */
62 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
63 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
64 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
65 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
67 /* used to decode ioctl numbers.. */
68 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
69 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
70 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
71 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
73 /* ...and for the drivers/sound files... */
75 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
76 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
77 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
78 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
79 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
81 #endif /* _ASMI386_IOCTL_H */