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89 lines
2.0 KiB
89 lines
2.0 KiB
/* |
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* Copyright 2010 Tilera Corporation. All Rights Reserved. |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License |
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* as published by the Free Software Foundation, version 2. |
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* |
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* This program is distributed in the hope that it will be useful, but |
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* WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or |
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* NON INFRINGEMENT. See the GNU General Public License for |
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* more details. |
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* Support code for the main lib/checksum.c. |
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*/ |
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#include <net/checksum.h> |
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#include <linux/module.h> |
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__wsum do_csum(const unsigned char *buff, int len) |
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{ |
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int odd, count; |
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unsigned long result = 0; |
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if (len <= 0) |
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goto out; |
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odd = 1 & (unsigned long) buff; |
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if (odd) { |
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result = (*buff << 8); |
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len--; |
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buff++; |
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} |
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count = len >> 1; /* nr of 16-bit words.. */ |
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if (count) { |
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if (2 & (unsigned long) buff) { |
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result += *(const unsigned short *)buff; |
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count--; |
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len -= 2; |
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buff += 2; |
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} |
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count >>= 1; /* nr of 32-bit words.. */ |
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if (count) { |
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#ifdef __tilegx__ |
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if (4 & (unsigned long) buff) { |
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unsigned int w = *(const unsigned int *)buff; |
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result = __insn_v2sadau(result, w, 0); |
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count--; |
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len -= 4; |
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buff += 4; |
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} |
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count >>= 1; /* nr of 64-bit words.. */ |
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#endif |
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/* |
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* This algorithm could wrap around for very |
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* large buffers, but those should be impossible. |
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*/ |
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BUG_ON(count >= 65530); |
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while (count) { |
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unsigned long w = *(const unsigned long *)buff; |
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count--; |
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buff += sizeof(w); |
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#ifdef __tilegx__ |
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result = __insn_v2sadau(result, w, 0); |
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#else |
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result = __insn_sadah_u(result, w, 0); |
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#endif |
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} |
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#ifdef __tilegx__ |
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if (len & 4) { |
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unsigned int w = *(const unsigned int *)buff; |
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result = __insn_v2sadau(result, w, 0); |
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buff += 4; |
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} |
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#endif |
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} |
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if (len & 2) { |
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result += *(const unsigned short *) buff; |
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buff += 2; |
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} |
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} |
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if (len & 1) |
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result += *buff; |
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result = csum_long(result); |
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if (odd) |
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result = swab16(result); |
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out: |
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return result; |
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}
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