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422 giacomo 1 
/* $Id: ioctl.h,v 1.1 2004-01-28 15:24:19 giacomo Exp $
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 *
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 * linux/ioctl.h for Linux by H.H. Bergman.
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 */
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#ifndef _ASMI386_IOCTL_H
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#define _ASMI386_IOCTL_H
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/* ioctl command encoding: 32 bits total, command in lower 16 bits,
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 * size of the parameter structure in the lower 14 bits of the
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 * upper 16 bits.
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 * Encoding the size of the parameter structure in the ioctl request
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 * is useful for catching programs compiled with old versions
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 * and to avoid overwriting user space outside the user buffer area.
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 * The highest 2 bits are reserved for indicating the ``access mode''.
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 * NOTE: This limits the max parameter size to 16kB -1 !
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 */
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/*
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 * The following is for compatibility across the various Linux
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 * platforms.  The i386 ioctl numbering scheme doesn't really enforce
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 * a type field.  De facto, however, the top 8 bits of the lower 16
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 * bits are indeed used as a type field, so we might just as well make
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 * this explicit here.  Please be sure to use the decoding macros
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 * below from now on.
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 */
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#define _IOC_NRBITS     8
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#define _IOC_TYPEBITS   8
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#define _IOC_SIZEBITS   14
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#define _IOC_DIRBITS    2
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#define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
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#define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
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#define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
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#define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
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#define _IOC_NRSHIFT    0
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#define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
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#define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
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#define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
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/*
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 * Direction bits.
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 */
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#define _IOC_NONE       0U
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#define _IOC_WRITE      1U
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#define _IOC_READ       2U
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#define _IOC(dir,type,nr,size) \
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        (((dir)  << _IOC_DIRSHIFT) | \
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         ((type) << _IOC_TYPESHIFT) | \
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         ((nr)   << _IOC_NRSHIFT) | \
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         ((size) << _IOC_SIZESHIFT))
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/* provoke compile error for invalid uses of size argument */
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extern int __invalid_size_argument_for_IOC;
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#define _IOC_TYPECHECK(t) \
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        ((sizeof(t) == sizeof(t[1]) && \
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          sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
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          sizeof(t) : __invalid_size_argument_for_IOC)
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/* used to create numbers */
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#define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
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#define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
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#define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
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#define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
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#define _IOR_BAD(type,nr,size)  _IOC(_IOC_READ,(type),(nr),sizeof(size))
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#define _IOW_BAD(type,nr,size)  _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
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#define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
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/* used to decode ioctl numbers.. */
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#define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
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#define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
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#define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
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#define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
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/* ...and for the drivers/sound files... */
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#define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
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#define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
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#define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
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#define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
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#define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
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#endif /* _ASMI386_IOCTL_H */