include/asm-mips/ioctl.h

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 1995, 96, 99, 2001 Ralf Baechle
   7  */
   8 #ifndef _ASM_IOCTL_H
   9 #define _ASM_IOCTL_H
  10
  11 /*
  12  * The original linux ioctl numbering scheme was just a general
  13  * "anything goes" setup, where more or less random numbers were
  14  * assigned.  Sorry, I was clueless when I started out on this.
  15  *
  16  * On the alpha, we'll try to clean it up a bit, using a more sane
  17  * ioctl numbering, and also trying to be compatible with OSF/1 in
  18  * the process. I'd like to clean it up for the i386 as well, but
  19  * it's so painful recognizing both the new and the old numbers..
  20  *
  21  * The same applies for for the MIPS ABI; in fact even the macros
  22  * from Linux/Alpha fit almost perfectly.
  23  */
  24
  25 #define _IOC_NRBITS     8
  26 #define _IOC_TYPEBITS   8
  27 #define _IOC_SIZEBITS   13
  28 #define _IOC_DIRBITS    3
  29
  30 #define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  31 #define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  32 #define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  33 #define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  34
  35 #define _IOC_NRSHIFT    0
  36 #define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  37 #define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  38 #define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  39
  40 /*
  41  * We to additionally limit parameters to a maximum 255 bytes.
  42  */
  43 #define _IOC_SLMASK     0xff
  44
  45 /*
  46  * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
  47  * And this turns out useful to catch old ioctl numbers in header
  48  * files for us.
  49  */
  50 #define _IOC_NONE       1U
  51 #define _IOC_READ       2U
  52 #define _IOC_WRITE      4U
  53
  54 /*
  55  * The following are included for compatibility
  56  */
  57 #define _IOC_VOID       0x20000000
  58 #define _IOC_OUT        0x40000000
  59 #define _IOC_IN         0x80000000
  60 #define _IOC_INOUT      (IOC_IN|IOC_OUT)
  61
  62 #define _IOC(dir,type,nr,size) \
  63         (((dir)  << _IOC_DIRSHIFT) | \
  64          ((type) << _IOC_TYPESHIFT) | \
  65          ((nr)   << _IOC_NRSHIFT) | \
  66          ((size) << _IOC_SIZESHIFT))
  67
  68 /* provoke compile error for invalid uses of size argument */
  69 extern unsigned int __invalid_size_argument_for_IOC;
  70 #define _IOC_TYPECHECK(t) \
  71         ((sizeof(t) == sizeof(t[1]) && \
  72           sizeof(t) < (1 << _IOC_SIZEBITS)) ? \
  73           sizeof(t) : __invalid_size_argument_for_IOC)
  74
  75 /* used to create numbers */
  76 #define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  77 #define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
  78 #define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  79 #define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  80 #define _IOR_BAD(type,nr,size)  _IOC(_IOC_READ,(type),(nr),sizeof(size))
  81 #define _IOW_BAD(type,nr,size)  _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  82 #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  83
  84
  85 /* used to decode them.. */
  86 #define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  87 #define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  88 #define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  89 #define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  90
  91 /* ...and for the drivers/sound files... */
  92
  93 #define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  94 #define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  95 #define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  96 #define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  97 #define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  98
  99 #endif /* _ASM_IOCTL_H */