arch/nios2/include/asm/checksum.h

   1 /*
   2  * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
   3  * Copyright (C) 2004 Microtronix Datacom Ltd.
   4  *
   5  * This file is subject to the terms and conditions of the GNU General Public
   6  * License. See the file "COPYING" in the main directory of this archive
   7  * for more details.
   8  */
   9
  10 #ifndef _ASM_NIOS_CHECKSUM_H
  11 #define _ASM_NIOS_CHECKSUM_H
  12
  13 /* Take these from lib/checksum.c */
  14 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  15 extern __wsum csum_partial_copy(const void *src, void *dst, int len,
  16                                 __wsum sum);
  17 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  18                                         int len, __wsum sum, int *csum_err);
  19 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  20         csum_partial_copy((src), (dst), (len), (sum))
  21
  22 extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  23 extern __sum16 ip_compute_csum(const void *buff, int len);
  24
  25 /*
  26  * Fold a partial checksum
  27  */
  28 static inline __sum16 csum_fold(__wsum sum)
  29 {
  30         __asm__ __volatile__(
  31                 "add    %0, %1, %0\n"
  32                 "cmpltu r8, %0, %1\n"
  33                 "srli   %0, %0, 16\n"
  34                 "add    %0, %0, r8\n"
  35                 "nor    %0, %0, %0\n"
  36                 : "=r" (sum)
  37                 : "r" (sum << 16), "0" (sum)
  38                 : "r8");
  39         return (__force __sum16) sum;
  40 }
  41
  42 /*
  43  * computes the checksum of the TCP/UDP pseudo-header
  44  * returns a 16-bit checksum, already complemented
  45  */
  46 #define csum_tcpudp_nofold csum_tcpudp_nofold
  47 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  48                                         unsigned short len,
  49                                         unsigned short proto,
  50                                         __wsum sum)
  51 {
  52         __asm__ __volatile__(
  53                 "add    %0, %1, %0\n"
  54                 "cmpltu r8, %0, %1\n"
  55                 "add    %0, %0, r8\n"   /* add carry */
  56                 "add    %0, %2, %0\n"
  57                 "cmpltu r8, %0, %2\n"
  58                 "add    %0, %0, r8\n"   /* add carry */
  59                 "add    %0, %3, %0\n"
  60                 "cmpltu r8, %0, %3\n"
  61                 "add    %0, %0, r8\n"   /* add carry */
  62                 : "=r" (sum), "=r" (saddr)
  63                 : "r" (daddr), "r" ((ntohs(len) << 16) + (proto * 256)),
  64                   "0" (sum),
  65                   "1" (saddr)
  66                 : "r8");
  67
  68         return sum;
  69 }
  70
  71 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  72                                         unsigned short len,
  73                                         unsigned short proto, __wsum sum)
  74 {
  75         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  76 }
  77
  78 #endif /* _ASM_NIOS_CHECKSUM_H */