include/asm-blackfin/checksum.h

   1 #ifndef _BFIN_CHECKSUM_H
   2 #define _BFIN_CHECKSUM_H
   3
   4 /*
   5  * MODIFIED FOR BFIN April 30, 2001 akbar.hussain@lineo.com
   6  *
   7  * computes the checksum of a memory block at buff, length len,
   8  * and adds in "sum" (32-bit)
   9  *
  10  * returns a 32-bit number suitable for feeding into itself
  11  * or csum_tcpudp_magic
  12  *
  13  * this function must be called with even lengths, except
  14  * for the last fragment, which may be odd
  15  *
  16  * it's best to have buff aligned on a 32-bit boundary
  17  */
  18 __wsum csum_partial(const void *buff, int len, __wsum sum);
  19
  20 /*
  21  * the same as csum_partial, but copies from src while it
  22  * checksums
  23  *
  24  * here even more important to align src and dst on a 32-bit (or even
  25  * better 64-bit) boundary
  26  */
  27
  28 __wsum csum_partial_copy(const void *src, void *dst,
  29                                int len, __wsum sum);
  30
  31 /*
  32  * the same as csum_partial_copy, but copies from user space.
  33  *
  34  * here even more important to align src and dst on a 32-bit (or even
  35  * better 64-bit) boundary
  36  */
  37
  38 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  39                                           int len, __wsum sum, int *csum_err);
  40
  41 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  42         csum_partial_copy((src), (dst), (len), (sum))
  43
  44 __sum16 ip_fast_csum(unsigned char *iph, unsigned int ihl);
  45
  46 /*
  47  *      Fold a partial checksum
  48  */
  49
  50 static inline __sum16 csum_fold(__wsum sum)
  51 {
  52         while (sum >> 16)
  53                 sum = (sum & 0xffff) + (sum >> 16);
  54         return ((~(sum << 16)) >> 16);
  55 }
  56
  57 /*
  58  * computes the checksum of the TCP/UDP pseudo-header
  59  * returns a 16-bit checksum, already complemented
  60  */
  61
  62 static inline __wsum
  63 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  64                    unsigned short proto, __wsum sum)
  65 {
  66
  67         __asm__ ("%0 = %0 + %1;\n\t"
  68                  "CC = AC0;\n\t"
  69                  "if !CC jump 4;\n\t"
  70                  "%0 = %0 + %4;\n\t"
  71                  "%0 = %0 + %2;\n\t"
  72                  "CC = AC0;\n\t"
  73                  "if !CC jump 4;\n\t"
  74                  "%0 = %0 + %4;\n\t"
  75                  "%0 = %0 + %3;\n\t"
  76                  "CC = AC0;\n\t"
  77                  "if !CC jump 4;\n\t"
  78                  "%0 = %0 + %4;\n\t"
  79                  "NOP;\n\t"
  80                  : "=d" (sum)
  81                  : "d" (daddr), "d" (saddr), "d" ((ntohs(len)<<16)+proto*256), "d" (1), "0"(sum));
  82
  83         return (sum);
  84 }
  85
  86 static inline __sum16
  87 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
  88                   unsigned short proto, __wsum sum)
  89 {
  90         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  91 }
  92
  93 /*
  94  * this routine is used for miscellaneous IP-like checksums, mainly
  95  * in icmp.c
  96  */
  97
  98 extern __sum16 ip_compute_csum(const void *buff, int len);
  99
 100 #endif                          /* _BFIN_CHECKSUM_H */