arch/nios2nommu/lib/checksum.c

   1 /*--------------------------------------------------------------------
   2  *
   3  * Derived from various works, Alpha, ix86, M68K, Sparc, ...et al
   4  *
   5  * Copyright (C) 2004   Microtronix Datacom Ltd
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  *
  18  * Jan/20/2004          dgt         NiosII
  19  *
  20  ---------------------------------------------------------------------*/
  21
  22 #include <net/checksum.h>
  23 #include <asm/checksum.h>
  24
  25 /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  26
  27 /*
  28  * computes the checksum of a memory block at buff, length len,
  29  * and adds in "sum" (32-bit)
  30  *
  31  * returns a 32-bit number suitable for feeding into itself
  32  * or csum_tcpudp_magic
  33  *
  34  * this function must be called with even lengths, except
  35  * for the last fragment, which may be odd
  36  *
  37  * it's best to have buff aligned on a 32-bit boundary
  38  */
  39
  40 unsigned int csum_partial(const unsigned char * buff, int len, unsigned int sum)
  41 {
  42 #if 0
  43         __asm__ __volatile__ ...//;dgt2;tmp;not (yet) available...
  44                          ...//;dgt2;tmp;NiosI didn't offer either...
  45 #else
  46         unsigned int result = do_csum(buff, len);
  47
  48         /* add in old sum, and carry.. */
  49         result += sum;
  50         if (sum > result)
  51                 result += 1;
  52         return result;
  53 #endif
  54 }
  55
  56
  57 /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
  58
  59
  60 /*
  61  * the same as csum_partial, but copies from fs:src while it
  62  * checksums
  63  *
  64  * here even more important to align src and dst on a 32-bit (or even
  65  * better 64-bit) boundary
  66  */
  67
  68 unsigned int csum_partial_copy(const char *src, char *dst, int len, int sum)
  69 {
  70         memcpy(dst, src, len);
  71         return csum_partial(dst, len, sum);
  72
  73 }