LXR linux/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 */
  14extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  15extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  16extern __sum16 ip_compute_csum(const void *buff, int len);
  17
  18/*
  19 * Fold a partial checksum
  20 */
  21static 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
  40static 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
  63static 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 */
  71