mirror of https://gitee.com/openkylin/linux.git
81 lines
2.7 KiB
C
81 lines
2.7 KiB
C
/* $Id: ioctl.h,v 1.3 1997/04/16 15:10:07 jes 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 _M68K_IOCTL_H
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#define _M68K_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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* I don't really have any idea about what this should look like, so
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* for the time being, this is heavily based on the PC definitions.
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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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/* 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),sizeof(size))
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#define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
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#define _IOWR(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 /* _M68K_IOCTL_H */
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