include/asm-v850/checksum.h

   1 /*
   2  * include/asm-v850/checksum.h -- Checksum ops
   3  *
   4  *  Copyright (C) 2001,2005  NEC Corporation
   5  *  Copyright (C) 2001,2005  Miles Bader <miles@gnu.org>
   6  *
   7  * This file is subject to the terms and conditions of the GNU General
   8  * Public License.  See the file COPYING in the main directory of this
   9  * archive for more details.
  10  *
  11  * Written by Miles Bader <miles@gnu.org>
  12  */
  13
  14 #ifndef __V850_CHECKSUM_H__
  15 #define __V850_CHECKSUM_H__
  16
  17 /*
  18  * computes the checksum of a memory block at buff, length len,
  19  * and adds in "sum" (32-bit)
  20  *
  21  * returns a 32-bit number suitable for feeding into itself
  22  * or csum_tcpudp_magic
  23  *
  24  * this function must be called with even lengths, except
  25  * for the last fragment, which may be odd
  26  *
  27  * it's best to have buff aligned on a 32-bit boundary
  28  */
  29 extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  30
  31 /*
  32  * the same as csum_partial, but copies from src while it
  33  * checksums
  34  *
  35  * here even more important to align src and dst on a 32-bit (or even
  36  * better 64-bit) boundary
  37  */
  38 extern __wsum csum_partial_copy_nocheck(const void *src,
  39                                    void *dst, int len, __wsum sum);
  40
  41
  42 /*
  43  * the same as csum_partial_copy, but copies from user space.
  44  *
  45  * here even more important to align src and dst on a 32-bit (or even
  46  * better 64-bit) boundary
  47  */
  48 extern __wsum csum_partial_copy_from_user (const void *src,
  49                                              void *dst,
  50                                              int len, __wsum sum,
  51                                              int *csum_err);
  52
  53 __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  54
  55 /*
  56  *      Fold a partial checksum
  57  */
  58 static inline __sum16 csum_fold (__wsum sum)
  59 {
  60         unsigned int result;
  61         /*
  62                                 %0              %1
  63               hsw %1, %0        H     L         L     H
  64               add %1, %0        H     L         H+L+C H+L
  65         */
  66         asm ("hsw %1, %0; add %1, %0" : "=&r" (result) : "r" (sum));
  67         return (__force __sum16)(~result >> 16);
  68 }
  69
  70
  71 /*
  72  * computes the checksum of the TCP/UDP pseudo-header
  73  * returns a 16-bit checksum, already complemented
  74  */
  75 static inline __wsum
  76 csum_tcpudp_nofold (__be32 saddr, __be32 daddr,
  77                     unsigned short len,
  78                     unsigned short proto, __wsum sum)
  79 {
  80         int __carry;
  81         __asm__ ("add %2, %0;"
  82                  "setf c, %1;"
  83                  "add %1, %0;"
  84                  "add %3, %0;"
  85                  "setf c, %1;"
  86                  "add %1, %0;"
  87                  "add %4, %0;"
  88                  "setf c, %1;"
  89                  "add %1, %0"
  90                  : "=&r" (sum), "=&r" (__carry)
  91                  : "r" (daddr), "r" (saddr),
  92                  "r" ((len + proto) << 8),
  93                  "0" (sum));
  94         return sum;
  95 }
  96
  97 static inline __sum16
  98 csum_tcpudp_magic (__be32 saddr, __be32 daddr,
  99                    unsigned short len,
 100                    unsigned short proto, __wsum sum)
 101 {
 102         return csum_fold (csum_tcpudp_nofold (saddr, daddr, len, proto, sum));
 103 }
 104
 105 /*
 106  * this routine is used for miscellaneous IP-like checksums, mainly
 107  * in icmp.c
 108  */
 109 extern __sum16 ip_compute_csum(const void *buff, int len);
 110
 111
 112 #endif /* __V850_CHECKSUM_H__ */