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 __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  16 extern __sum16 ip_compute_csum(const void *buff, int len);
  17
  18 /*
  19  * Fold a partial checksum
  20  */
  21 static inline __sum16 csum_fold(__wsum sum)
  22 {
  23         __asm__ __volatile__(
  24                 "add    %0, %1, %0\n"
  25                 "cmpltu r8, %0, %1\n"
  26                 "srli   %0, %0, 16\n"
  27                 "add    %0, %0, r8\n"
  28                 "nor    %0, %0, %0\n"
  29                 : "=r" (sum)
  30                 : "r" (sum << 16), "0" (sum)
  31                 : "r8");
  32         return (__force __sum16) sum;
  33 }
  34
  35 /*
  36  * computes the checksum of the TCP/UDP pseudo-header
  37  * returns a 16-bit checksum, already complemented
  38  */
  39 #define csum_tcpudp_nofold csum_tcpudp_nofold
  40 static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
  41                                         __u32 len, __u8 proto,
  42                                         __wsum sum)
  43 {
  44         __asm__ __volatile__(
  45                 "add    %0, %1, %0\n"
  46                 "cmpltu r8, %0, %1\n"
  47                 "add    %0, %0, r8\n"   /* add carry */
  48                 "add    %0, %2, %0\n"
  49                 "cmpltu r8, %0, %2\n"
  50                 "add    %0, %0, r8\n"   /* add carry */
  51                 "add    %0, %3, %0\n"
  52                 "cmpltu r8, %0, %3\n"
  53                 "add    %0, %0, r8\n"   /* add carry */
  54                 : "=r" (sum), "=r" (saddr)
  55                 : "r" (daddr), "r" ((len + proto) << 8),
  56                   "0" (sum),
  57                   "1" (saddr)
  58                 : "r8");
  59
  60         return sum;
  61 }
  62
  63 static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,
  64                                         __u32 len, __u8 proto,
  65                                         __wsum sum)
  66 {
  67         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  68 }
  69
  70 #endif /* _ASM_NIOS_CHECKSUM_H */