1 /*
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2022 NVIDIA corporation & affiliates.
5 * Copyright (c) 2013 François Tigeot
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #ifndef _LINUXKPI_LINUX_HASH_H_
30 #define _LINUXKPI_LINUX_HASH_H_
31
32 #include <sys/hash.h>
33 #include <sys/param.h>
34 #include <sys/systm.h>
35
36 #include <asm/types.h>
37
38 #include <linux/bitops.h>
39
40 static inline u64
hash_64(u64 val,u8 bits)41 hash_64(u64 val, u8 bits)
42 {
43 u64 ret;
44 u8 x;
45
46 ret = bits;
47
48 for (x = 0; x != sizeof(ret); x++) {
49 u64 chunk = (val >> (8 * x)) & 0xFF;
50 ret = HASHSTEP(ret, chunk);
51 }
52 return (ret >> (64 - bits));
53 }
54
55 static inline u32
hash_32(u32 val,u8 bits)56 hash_32(u32 val, u8 bits)
57 {
58 u32 ret;
59 u8 x;
60
61 ret = bits;
62
63 for (x = 0; x != sizeof(ret); x++) {
64 u32 chunk = (val >> (8 * x)) & 0xFF;
65 ret = HASHSTEP(ret, chunk);
66 }
67 return (ret >> (32 - bits));
68 }
69
70 #if BITS_PER_LONG == 64
71 #define hash_long(...) hash_64(__VA_ARGS__)
72 #else
73 #define hash_long(...) hash_32(__VA_ARGS__)
74 #endif
75
76 #endif /* _LINUXKPI_LINUX_HASH_H_ */
77