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  */
  25 static 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  */
  37 static inline __sum16
  38 ip_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  */
  69 static inline __wsum
  70 csum_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 */