include/asm-ia64/ioctl.h

   1 #ifndef _ASM_IA64_IOCTL_H
   2 #define _ASM_IA64_IOCTL_H
   3
   4 /*
   5  * Based on <asm-i386/ioctl.h>.
   6  *
   7  * Modified 1998, 1999
   8  *      David Mosberger-Tang <davidm@hpl.hp.com>, Hewlett-Packard Co
   9  */
  10
  11 /* ioctl command encoding: 32 bits total, command in lower 16 bits,
  12  * size of the parameter structure in the lower 14 bits of the
  13  * upper 16 bits.
  14  * Encoding the size of the parameter structure in the ioctl request
  15  * is useful for catching programs compiled with old versions
  16  * and to avoid overwriting user space outside the user buffer area.
  17  * The highest 2 bits are reserved for indicating the ``access mode''.
  18  * NOTE: This limits the max parameter size to 16kB -1 !
  19  */
  20
  21 /*
  22  * The following is for compatibility across the various Linux
  23  * platforms.  The ia64 ioctl numbering scheme doesn't really enforce
  24  * a type field.  De facto, however, the top 8 bits of the lower 16
  25  * bits are indeed used as a type field, so we might just as well make
  26  * this explicit here.  Please be sure to use the decoding macros
  27  * below from now on.
  28  */
  29 #define _IOC_NRBITS     8
  30 #define _IOC_TYPEBITS   8
  31 #define _IOC_SIZEBITS   14
  32 #define _IOC_DIRBITS    2
  33
  34 #define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  35 #define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  36 #define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  37 #define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  38
  39 #define _IOC_NRSHIFT    0
  40 #define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  41 #define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  42 #define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  43
  44 /*
  45  * Direction bits.
  46  */
  47 #define _IOC_NONE       0U
  48 #define _IOC_WRITE      1U
  49 #define _IOC_READ       2U
  50
  51 #define _IOC(dir,type,nr,size) \
  52         (((dir)  << _IOC_DIRSHIFT) | \
  53          ((type) << _IOC_TYPESHIFT) | \
  54          ((nr)   << _IOC_NRSHIFT) | \
  55          ((size) << _IOC_SIZESHIFT))
  56
  57 /* used to create numbers */
  58 #define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  59 #define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),sizeof(size))
  60 #define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  61 #define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  62
  63 /* used to decode ioctl numbers.. */
  64 #define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  65 #define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  66 #define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  67 #define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  68
  69 /* ...and for the drivers/sound files... */
  70
  71 #define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  72 #define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  73 #define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  74 #define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  75 #define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  76
  77 #endif /* _ASM_IA64_IOCTL_H */