1 #ifndef _ASM_GENERIC_IOCTL_H
2 #define _ASM_GENERIC_IOCTL_H
4 /* ioctl command encoding: 32 bits total, command in lower 16 bits,
5 * size of the parameter structure in the lower 14 bits of the
7 * Encoding the size of the parameter structure in the ioctl request
8 * is useful for catching programs compiled with old versions
9 * and to avoid overwriting user space outside the user buffer area.
10 * The highest 2 bits are reserved for indicating the ``access mode''.
11 * NOTE: This limits the max parameter size to 16kB -1 !
15 * The following is for compatibility across the various Linux
16 * platforms. The generic ioctl numbering scheme doesn't really enforce
17 * a type field. De facto, however, the top 8 bits of the lower 16
18 * bits are indeed used as a type field, so we might just as well make
19 * this explicit here. Please be sure to use the decoding macros
23 #define _IOC_TYPEBITS 8
26 * Let any architecture override either of the following before
27 * including this file.
31 # define _IOC_SIZEBITS 14
35 # 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)
49 * Direction bits, which any architecture can choose to override
50 * before including this file.
58 # define _IOC_WRITE 1U
65 #define _IOC(dir,type,nr,size) \
66 (((dir) << _IOC_DIRSHIFT) | \
67 ((type) << _IOC_TYPESHIFT) | \
68 ((nr) << _IOC_NRSHIFT) | \
69 ((size) << _IOC_SIZESHIFT))
71 #define _IOC_TYPECHECK(t) (sizeof(t))
73 /* used to create numbers */
74 #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
75 #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
76 #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
77 #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
78 #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
79 #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
80 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
82 /* used to decode ioctl numbers.. */
83 #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
84 #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
85 #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
86 #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
88 /* ...and for the drivers/sound files... */
90 #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
91 #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
92 #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
93 #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
94 #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
96 #endif /* _ASM_GENERIC_IOCTL_H */