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  */
  28 static 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  */
  40 static inline __sum16
  41 ip_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  */
  72 static inline __wsum
  73 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
  74                    __u8 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 */