LXR linux/arch/arc/include/asm/checksum.h

   1/*
   2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License version 2 as
   6 * published by the Free Software Foundation.
   7 *
   8 * Joern Rennecke  <joern.rennecke@embecosm.com>: Jan 2012
   9 *  -Insn Scheduling improvements to csum core routines.
  10 *      = csum_fold( ) largely derived from ARM version.
  11 *      = ip_fast_cum( ) to have module scheduling
  12 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.
  13 *   worked around by adding memory clobber to ip_fast_csum( )
  14 *
  15 * vineetg: May 2010
  16 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
  17 */
  18
  19#ifndef _ASM_ARC_CHECKSUM_H
  20#define _ASM_ARC_CHECKSUM_H
  21
  22/*
  23 *      Fold a partial checksum
  24 *
  25 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit
  26 *  added back and final sword result inverted.
  27 */
  28static inline __sum16 csum_fold(__wsum s)
  29{
  30        unsigned r = s << 16 | s >> 16; /* ror */
  31        s = ~s;
  32        s -= r;
  33        return s >> 16;
  34}
  35
  36/*
  37 *      This is a version of ip_compute_csum() optimized for IP headers,
  38 *      which always checksum on 4 octet boundaries.
  39 */
  40static inline __sum16
  41ip_fast_csum(const void *iph, unsigned int ihl)
  42{
  43        const void *ptr = iph;
  44        unsigned int tmp, tmp2, sum;
  45
  46        __asm__(
  47        "       ld.ab  %0, [%3, 4]              \n"
  48        "       ld.ab  %2, [%3, 4]              \n"
  49        "       sub    %1, %4, 2                \n"
  50        "       lsr.f  lp_count, %1, 1          \n"
  51        "       bcc    0f                       \n"
  52        "       add.f  %0, %0, %2               \n"
  53        "       ld.ab  %2, [%3, 4]              \n"
  54        "0:     lp     1f                       \n"
  55        "       ld.ab  %1, [%3, 4]              \n"
  56        "       adc.f  %0, %0, %2               \n"
  57        "       ld.ab  %2, [%3, 4]              \n"
  58        "       adc.f  %0, %0, %1               \n"
  59        "1:     adc.f  %0, %0, %2               \n"
  60        "       add.cs %0,%0,1                  \n"
  61        : "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
  62        : "r"(ihl)
  63        : "cc", "lp_count", "memory");
  64
  65        return csum_fold(sum);
  66}
  67
  68/*
  69 * TCP pseudo Header is 12 bytes:
  70 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
  71 */
  72static inline __wsum
  73csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  74                   unsigned short proto, __wsum sum)
  75{
  76        __asm__ __volatile__(
  77        "       add.f %0, %0, %1        \n"
  78        "       adc.f %0, %0, %2        \n"
  79        "       adc.f %0, %0, %3        \n"
  80        "       adc.f %0, %0, %4        \n"
  81        "       adc   %0, %0, 0         \n"
  82        : "+&r"(sum)
  83        : "r"(saddr), "r"(daddr),
  84#ifdef CONFIG_CPU_BIG_ENDIAN
  85          "r"(len),
  86#else
  87          "r"(len << 8),
  88#endif
  89          "r"(htons(proto))
  90        : "cc");
  91
  92        return sum;
  93}
  94
  95#define csum_fold csum_fold
  96#define ip_fast_csum ip_fast_csum
  97#define csum_tcpudp_nofold csum_tcpudp_nofold
  98
  99#include <asm-generic/checksum.h>
 100
 101#endif /* _ASM_ARC_CHECKSUM_H */
 102