| Chris Metcalf | 867e359 | 2010-05-28 23:09:12 -0400 | [diff] [blame] | 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 | |
| Chris Metcalf | 867e359 | 2010-05-28 23:09:12 -0400 | [diff] [blame] | 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; |
| Chris Metcalf | 10104a1 | 2012-04-28 15:41:39 -0400 | [diff] [blame] | 84 | result = csum_long(result); |
| Chris Metcalf | 867e359 | 2010-05-28 23:09:12 -0400 | [diff] [blame] | 85 | if (odd) |
| 86 | result = swab16(result); |
| 87 | out: |
| 88 | return result; |
| 89 | } |