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