sys/dev/drm/include/linux/hash.h

   1 /*
   2  * Copyright (c) 2013 François Tigeot
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice unmodified, this list of conditions, and the following
  10  *    disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #ifndef _LINUX_HASH_H_
  28 #define _LINUX_HASH_H_
  29
  30 #include <sys/hash.h>
  31
  32 static inline u64 hash_64(u64 val, unsigned int bits)
  33 {
  34         u64 ret;
  35
  36         ret = (uint64_t)hash32_buf(&val, sizeof(val), bits);
  37
  38         return ret >> (64 - bits);
  39 }
  40
  41 static inline u32 hash_32(u32 val, unsigned int bits)
  42 {
  43         u32 ret;
  44
  45         ret = hash32_buf(&val, sizeof(val), bits);
  46
  47         return ret >> (32 - bits);
  48 }
  49
  50 #if BITS_PER_LONG == 64 /* amd64 */
  51 #define hash_long(val, bits) hash_64(val, bits)
  52 #else   /* i386 */
  53 #define hash_long(val, bits) hash_32(val, bits)
  54 #endif
  55
  56 #endif  /* _LINUX_HASH_H_ */