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867e359b CM |
1 | /* |
2 | * Copyright 2010 Tilera Corporation. All Rights Reserved. | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or | |
5 | * modify it under the terms of the GNU General Public License | |
6 | * as published by the Free Software Foundation, version 2. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but | |
9 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
10 | * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or | |
11 | * NON INFRINGEMENT. See the GNU General Public License for | |
12 | * more details. | |
13 | * Support code for the main lib/checksum.c. | |
14 | */ | |
15 | ||
16 | #include <net/checksum.h> | |
17 | #include <linux/module.h> | |
18 | ||
867e359b CM |
19 | __wsum do_csum(const unsigned char *buff, int len) |
20 | { | |
21 | int odd, count; | |
22 | unsigned long result = 0; | |
23 | ||
24 | if (len <= 0) | |
25 | goto out; | |
26 | odd = 1 & (unsigned long) buff; | |
27 | if (odd) { | |
28 | result = (*buff << 8); | |
29 | len--; | |
30 | buff++; | |
31 | } | |
32 | count = len >> 1; /* nr of 16-bit words.. */ | |
33 | if (count) { | |
34 | if (2 & (unsigned long) buff) { | |
35 | result += *(const unsigned short *)buff; | |
36 | count--; | |
37 | len -= 2; | |
38 | buff += 2; | |
39 | } | |
40 | count >>= 1; /* nr of 32-bit words.. */ | |
41 | if (count) { | |
42 | #ifdef __tilegx__ | |
43 | if (4 & (unsigned long) buff) { | |
44 | unsigned int w = *(const unsigned int *)buff; | |
45 | result = __insn_v2sadau(result, w, 0); | |
46 | count--; | |
47 | len -= 4; | |
48 | buff += 4; | |
49 | } | |
50 | count >>= 1; /* nr of 64-bit words.. */ | |
51 | #endif | |
52 | ||
53 | /* | |
54 | * This algorithm could wrap around for very | |
55 | * large buffers, but those should be impossible. | |
56 | */ | |
57 | BUG_ON(count >= 65530); | |
58 | ||
59 | while (count) { | |
60 | unsigned long w = *(const unsigned long *)buff; | |
61 | count--; | |
62 | buff += sizeof(w); | |
63 | #ifdef __tilegx__ | |
64 | result = __insn_v2sadau(result, w, 0); | |
65 | #else | |
66 | result = __insn_sadah_u(result, w, 0); | |
67 | #endif | |
68 | } | |
69 | #ifdef __tilegx__ | |
70 | if (len & 4) { | |
71 | unsigned int w = *(const unsigned int *)buff; | |
72 | result = __insn_v2sadau(result, w, 0); | |
73 | buff += 4; | |
74 | } | |
75 | #endif | |
76 | } | |
77 | if (len & 2) { | |
78 | result += *(const unsigned short *) buff; | |
79 | buff += 2; | |
80 | } | |
81 | } | |
82 | if (len & 1) | |
83 | result += *buff; | |
10104a1a | 84 | result = csum_long(result); |
867e359b CM |
85 | if (odd) |
86 | result = swab16(result); | |
87 | out: | |
88 | return result; | |
89 | } |