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

   1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
   2 #ifndef _ALPHA_IOCTL_H
   3 #define _ALPHA_IOCTL_H
   4
   5 /*
   6  * The original linux ioctl numbering scheme was just a general
   7  * "anything goes" setup, where more or less random numbers were
   8  * assigned.  Sorry, I was clueless when I started out on this.
   9  *
  10  * On the alpha, we'll try to clean it up a bit, using a more sane
  11  * ioctl numbering, and also trying to be compatible with OSF/1 in
  12  * the process. I'd like to clean it up for the i386 as well, but
  13  * it's so painful recognizing both the new and the old numbers..
  14  */
  15
  16 #define _IOC_NRBITS     8
  17 #define _IOC_TYPEBITS   8
  18 #define _IOC_SIZEBITS   13
  19 #define _IOC_DIRBITS    3
  20
  21 #define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  22 #define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  23 #define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  24 #define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  25
  26 #define _IOC_NRSHIFT    0
  27 #define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  28 #define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  29 #define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  30
  31 /*
  32  * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
  33  * And this turns out useful to catch old ioctl numbers in header
  34  * files for us.
  35  */
  36 #define _IOC_NONE       1U
  37 #define _IOC_READ       2U
  38 #define _IOC_WRITE      4U
  39
  40 #define _IOC(dir,type,nr,size)                  \
  41         ((unsigned int)                         \
  42          (((dir)  << _IOC_DIRSHIFT) |           \
  43           ((type) << _IOC_TYPESHIFT) |          \
  44           ((nr)   << _IOC_NRSHIFT) |            \
  45           ((size) << _IOC_SIZESHIFT)))
  46
  47 /* used to create numbers */
  48 #define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  49 #define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),sizeof(size))
  50 #define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  51 #define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  52
  53 /* used to decode them.. */
  54 #define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  55 #define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  56 #define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  57 #define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  58
  59 /* ...and for the drivers/sound files... */
  60
  61 #define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  62 #define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  63 #define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  64 #define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  65 #define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  66
  67 #endif /* _ALPHA_IOCTL_H */