LXR linux/arch/alpha/include/uapi/asm/ioctl.h

   1#ifndef _ALPHA_IOCTL_H
   2#define _ALPHA_IOCTL_H
   3
   4/*
   5 * The original linux ioctl numbering scheme was just a general
   6 * "anything goes" setup, where more or less random numbers were
   7 * assigned.  Sorry, I was clueless when I started out on this.
   8 *
   9 * On the alpha, we'll try to clean it up a bit, using a more sane
  10 * ioctl numbering, and also trying to be compatible with OSF/1 in
  11 * the process. I'd like to clean it up for the i386 as well, but
  12 * it's so painful recognizing both the new and the old numbers..
  13 */
  14
  15#define _IOC_NRBITS     8
  16#define _IOC_TYPEBITS   8
  17#define _IOC_SIZEBITS   13
  18#define _IOC_DIRBITS    3
  19
  20#define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  21#define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  22#define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  23#define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  24
  25#define _IOC_NRSHIFT    0
  26#define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  27#define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  28#define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  29
  30/*
  31 * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
  32 * And this turns out useful to catch old ioctl numbers in header
  33 * files for us.
  34 */
  35#define _IOC_NONE       1U
  36#define _IOC_READ       2U
  37#define _IOC_WRITE      4U
  38
  39#define _IOC(dir,type,nr,size)                  \
  40        ((unsigned int)                         \
  41         (((dir)  << _IOC_DIRSHIFT) |           \
  42          ((type) << _IOC_TYPESHIFT) |          \
  43          ((nr)   << _IOC_NRSHIFT) |            \
  44          ((size) << _IOC_SIZESHIFT)))
  45
  46/* used to create numbers */
  47#define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  48#define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),sizeof(size))
  49#define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  50#define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  51
  52/* used to decode them.. */
  53#define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  54#define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  55#define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  56#define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  57
  58/* ...and for the drivers/sound files... */
  59
  60#define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  61#define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  62#define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  63#define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  64#define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  65
  66#endif /* _ALPHA_IOCTL_H */
  67