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 unsigned int csum_partial(const unsigned char *buff, int len, unsigned int 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 unsigned int csum_partial_copy(const unsigned char *src, unsigned char *dst,
  29                                int len, int 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 unsigned int csum_partial_copy_from_user(const unsigned char *src,
  39                                                 unsigned char *dst, int len,
  40                                                 int sum, int *csum_err);
  41
  42 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  43         csum_partial_copy((src), (dst), (len), (sum))
  44
  45 unsigned short ip_fast_csum(unsigned char *iph, unsigned int ihl);
  46
  47 /*
  48  *      Fold a partial checksum
  49  */
  50
  51 static inline unsigned int csum_fold(unsigned int sum)
  52 {
  53         while (sum >> 16)
  54                 sum = (sum & 0xffff) + (sum >> 16);
  55         return ((~(sum << 16)) >> 16);
  56 }
  57
  58 /*
  59  * computes the checksum of the TCP/UDP pseudo-header
  60  * returns a 16-bit checksum, already complemented
  61  */
  62
  63 static inline unsigned int
  64 csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
  65                    unsigned short proto, unsigned int sum)
  66 {
  67
  68         __asm__ ("%0 = %0 + %1;\n\t"
  69                  "CC = AC0;\n\t"
  70                  "if !CC jump 4;\n\t"
  71                  "%0 = %0 + %4;\n\t"
  72                  "%0 = %0 + %2;\n\t"
  73                  "CC = AC0;\n\t"
  74                  "if !CC jump 4;\n\t"
  75                  "%0 = %0 + %4;\n\t"
  76                  "%0 = %0 + %3;\n\t"
  77                  "CC = AC0;\n\t"
  78                  "if !CC jump 4;\n\t"
  79                  "%0 = %0 + %4;\n\t"
  80                  "NOP;\n\t"
  81                  : "=d" (sum)
  82                  : "d" (daddr), "d" (saddr), "d" ((ntohs(len)<<16)+proto*256), "d" (1), "0"(sum));
  83
  84         return (sum);
  85 }
  86
  87 static inline unsigned short int
  88 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr, unsigned short len,
  89                   unsigned short proto, unsigned int sum)
  90 {
  91         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  92 }
  93
  94 /*
  95  * this routine is used for miscellaneous IP-like checksums, mainly
  96  * in icmp.c
  97  */
  98
  99 extern unsigned short ip_compute_csum(const unsigned char *buff, int len);
 100
 101 #endif                          /* _BFIN_CHECKSUM_H */