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

   1/* SPDX-License-Identifier: GPL-2.0-only */
   2/*
   3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   4 *
   5 * Joern Rennecke  <joern.rennecke@embecosm.com>: Jan 2012
   6 *  -Insn Scheduling improvements to csum core routines.
   7 *      = csum_fold( ) largely derived from ARM version.
   8 *      = ip_fast_cum( ) to have module scheduling
   9 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.
  10 *   worked around by adding memory clobber to ip_fast_csum( )
  11 *
  12 * vineetg: May 2010
  13 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
  14 */
  15
  16#ifndef _ASM_ARC_CHECKSUM_H
  17#define _ASM_ARC_CHECKSUM_H
  18
  19/*
  20 *      Fold a partial checksum
  21 *
  22 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit
  23 *  added back and final sword result inverted.
  24 */
  25static inline __sum16 csum_fold(__wsum s)
  26{
  27        unsigned r = s << 16 | s >> 16; /* ror */
  28        s = ~s;
  29        s -= r;
  30        return s >> 16;
  31}
  32
  33/*
  34 *      This is a version of ip_compute_csum() optimized for IP headers,
  35 *      which always checksum on 4 octet boundaries.
  36 */
  37static inline __sum16
  38ip_fast_csum(const void *iph, unsigned int ihl)
  39{
  40        const void *ptr = iph;
  41        unsigned int tmp, tmp2, sum;
  42
  43        __asm__(
  44        "       ld.ab  %0, [%3, 4]              \n"
  45        "       ld.ab  %2, [%3, 4]              \n"
  46        "       sub    %1, %4, 2                \n"
  47        "       lsr.f  lp_count, %1, 1          \n"
  48        "       bcc    0f                       \n"
  49        "       add.f  %0, %0, %2               \n"
  50        "       ld.ab  %2, [%3, 4]              \n"
  51        "0:     lp     1f                       \n"
  52        "       ld.ab  %1, [%3, 4]              \n"
  53        "       adc.f  %0, %0, %2               \n"
  54        "       ld.ab  %2, [%3, 4]              \n"
  55        "       adc.f  %0, %0, %1               \n"
  56        "1:     adc.f  %0, %0, %2               \n"
  57        "       add.cs %0,%0,1                  \n"
  58        : "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
  59        : "r"(ihl)
  60        : "cc", "lp_count", "memory");
  61
  62        return csum_fold(sum);
  63}
  64
  65/*
  66 * TCP pseudo Header is 12 bytes:
  67 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
  68 */
  69static inline __wsum
  70csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
  71                   __u8 proto, __wsum sum)
  72{
  73        __asm__ __volatile__(
  74        "       add.f %0, %0, %1        \n"
  75        "       adc.f %0, %0, %2        \n"
  76        "       adc.f %0, %0, %3        \n"
  77        "       adc.f %0, %0, %4        \n"
  78        "       adc   %0, %0, 0         \n"
  79        : "+&r"(sum)
  80        : "r"(saddr), "r"(daddr),
  81#ifdef CONFIG_CPU_BIG_ENDIAN
  82          "r"(len),
  83#else
  84          "r"(len << 8),
  85#endif
  86          "r"(htons(proto))
  87        : "cc");
  88
  89        return sum;
  90}
  91
  92#define csum_fold csum_fold
  93#define ip_fast_csum ip_fast_csum
  94#define csum_tcpudp_nofold csum_tcpudp_nofold
  95
  96#include <asm-generic/checksum.h>
  97
  98#endif /* _ASM_ARC_CHECKSUM_H */
  99