1. 根目录:
2. arch
3. sparc
4. include
5. uapi
6. asm
7. ioctl.h

#ifndef _SPARC_IOCTL_H
#define _SPARC_IOCTL_H

/*
 * Our DIR and SIZE overlap in order to simulteneously provide
 * a non-zero _IOC_NONE (for binary compatibility) and
 * 14 bits of size as on i386. Here's the layout:
 *
 *   0xE0000000   DIR
 *   0x80000000     DIR = WRITE
 *   0x40000000     DIR = READ
 *   0x20000000     DIR = NONE
 *   0x3FFF0000   SIZE (overlaps NONE bit)
 *   0x0000FF00   TYPE
 *   0x000000FF   NR (CMD)
 */

#define _IOC_NRBITS      8
#define _IOC_TYPEBITS    8
#define _IOC_SIZEBITS   13	/* Actually 14, see below. */
#define _IOC_DIRBITS     3

#define _IOC_NRMASK      ((1 << _IOC_NRBITS)-1)
#define _IOC_TYPEMASK    ((1 << _IOC_TYPEBITS)-1)
#define _IOC_SIZEMASK    ((1 << _IOC_SIZEBITS)-1)
#define _IOC_XSIZEMASK   ((1 << (_IOC_SIZEBITS+1))-1)
#define _IOC_DIRMASK     ((1 << _IOC_DIRBITS)-1)

#define _IOC_NRSHIFT     0
#define _IOC_TYPESHIFT   (_IOC_NRSHIFT + _IOC_NRBITS)
#define _IOC_SIZESHIFT   (_IOC_TYPESHIFT + _IOC_TYPEBITS)
#define _IOC_DIRSHIFT    (_IOC_SIZESHIFT + _IOC_SIZEBITS)

#define _IOC_NONE        1U
#define _IOC_READ        2U
#define _IOC_WRITE       4U

#define _IOC(dir,type,nr,size) \
        (((dir)  << _IOC_DIRSHIFT) | \
         ((type) << _IOC_TYPESHIFT) | \
         ((nr)   << _IOC_NRSHIFT) | \
         ((size) << _IOC_SIZESHIFT))

#define _IO(type,nr)        _IOC(_IOC_NONE,(type),(nr),0)
#define _IOR(type,nr,size)  _IOC(_IOC_READ,(type),(nr),sizeof(size))
#define _IOW(type,nr,size)  _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
#define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))

/* Used to decode ioctl numbers in drivers despite the leading underscore... */
#define _IOC_DIR(nr)    \
 ( (((((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) & (_IOC_WRITE|_IOC_READ)) != 0)?   \
                            (((nr) >> _IOC_DIRSHIFT) & (_IOC_WRITE|_IOC_READ)):  \
                            (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) )
#define _IOC_TYPE(nr)       (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
#define _IOC_NR(nr)         (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
#define _IOC_SIZE(nr)   \
 ((((((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK) & (_IOC_WRITE|_IOC_READ)) == 0)?    \
                         0: (((nr) >> _IOC_SIZESHIFT) & _IOC_XSIZEMASK))

/* ...and for the PCMCIA and sound. */
#define IOC_IN          (_IOC_WRITE << _IOC_DIRSHIFT)
#define IOC_OUT         (_IOC_READ << _IOC_DIRSHIFT)
#define IOC_INOUT       ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
#define IOCSIZE_MASK    (_IOC_XSIZEMASK << _IOC_SIZESHIFT)
#define IOCSIZE_SHIFT   (_IOC_SIZESHIFT)

#endif /* !(_SPARC_IOCTL_H) */