include/asm-mips/ioctl.h

   1 /*
   2  * Linux ioctl() stuff.
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 1995, 1996 by Ralf Baechle
   9  */
  10 #ifndef __ASM_MIPS_IOCTL_H
  11 #define __ASM_MIPS_IOCTL_H
  12
  13 /*
  14  * The original linux ioctl numbering scheme was just a general
  15  * "anything goes" setup, where more or less random numbers were
  16  * assigned.  Sorry, I was clueless when I started out on this.
  17  *
  18  * On the alpha, we'll try to clean it up a bit, using a more sane
  19  * ioctl numbering, and also trying to be compatible with OSF/1 in
  20  * the process. I'd like to clean it up for the i386 as well, but
  21  * it's so painful recognizing both the new and the old numbers..
  22  *
  23  * The same applies for for the MIPS ABI; in fact even the macros
  24  * from Linux/Alpha fit almost perfectly.
  25  */
  26
  27 #define _IOC_NRBITS     8
  28 #define _IOC_TYPEBITS   8
  29 #define _IOC_SIZEBITS   13
  30 #define _IOC_DIRBITS    3
  31
  32 #define _IOC_NRMASK     ((1 << _IOC_NRBITS)-1)
  33 #define _IOC_TYPEMASK   ((1 << _IOC_TYPEBITS)-1)
  34 #define _IOC_SIZEMASK   ((1 << _IOC_SIZEBITS)-1)
  35 #define _IOC_DIRMASK    ((1 << _IOC_DIRBITS)-1)
  36
  37 #define _IOC_NRSHIFT    0
  38 #define _IOC_TYPESHIFT  (_IOC_NRSHIFT+_IOC_NRBITS)
  39 #define _IOC_SIZESHIFT  (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  40 #define _IOC_DIRSHIFT   (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  41
  42 /*
  43  * We to additionally limit parameters to a maximum 255 bytes.
  44  */
  45 #define _IOC_SLMASK     0xff
  46
  47 /*
  48  * Direction bits _IOC_NONE could be 0, but OSF/1 gives it a bit.
  49  * And this turns out useful to catch old ioctl numbers in header
  50  * files for us.
  51  */
  52 #define _IOC_NONE       1U
  53 #define _IOC_READ       2U
  54 #define _IOC_WRITE      4U
  55
  56 /*
  57  * The following are included for compatibility
  58  */
  59 #define _IOC_VOID       0x20000000
  60 #define _IOC_OUT        0x40000000
  61 #define _IOC_IN         0x80000000
  62 #define _IOC_INOUT      (IOC_IN|IOC_OUT)
  63
  64 #define _IOC(dir,type,nr,size) \
  65         (((dir)  << _IOC_DIRSHIFT) | \
  66          ((type) << _IOC_TYPESHIFT) | \
  67          ((nr)   << _IOC_NRSHIFT) | \
  68          (((size) & _IOC_SLMASK) << _IOC_SIZESHIFT))
  69
  70 /* used to create numbers */
  71 #define _IO(type,nr)            _IOC(_IOC_NONE,(type),(nr),0)
  72 #define _IOR(type,nr,size)      _IOC(_IOC_READ,(type),(nr),sizeof(size))
  73 #define _IOW(type,nr,size)      _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  74 #define _IOWR(type,nr,size)     _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  75
  76 /* used to decode them.. */
  77 #define _IOC_DIR(nr)            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  78 #define _IOC_TYPE(nr)           (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  79 #define _IOC_NR(nr)             (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  80 #define _IOC_SIZE(nr)           (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  81
  82 /* ...and for the drivers/sound files... */
  83
  84 #define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
  85 #define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
  86 #define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  87 #define IOCSIZE_MASK    (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  88 #define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)
  89
  90 #endif /* __ASM_MIPS_IOCTL_H */