arch/blackfin/include/asm/checksum.h

   1 /*
   2  * Copyright 2004-2009 Analog Devices Inc.
   3  *                     akbar.hussain@lineo.com
   4  *
   5  * Licensed under the GPL-2 or later.
   6  */
   7
   8 #ifndef _BFIN_CHECKSUM_H
   9 #define _BFIN_CHECKSUM_H
  10
  11 /*
  12  * computes the checksum of a memory block at buff, length len,
  13  * and adds in "sum" (32-bit)
  14  *
  15  * returns a 32-bit number suitable for feeding into itself
  16  * or csum_tcpudp_magic
  17  *
  18  * this function must be called with even lengths, except
  19  * for the last fragment, which may be odd
  20  *
  21  * it's best to have buff aligned on a 32-bit boundary
  22  */
  23 __wsum csum_partial(const void *buff, int len, __wsum sum);
  24
  25 /*
  26  * the same as csum_partial, but copies from src while it
  27  * checksums
  28  *
  29  * here even more important to align src and dst on a 32-bit (or even
  30  * better 64-bit) boundary
  31  */
  32
  33 __wsum csum_partial_copy(const void *src, void *dst,
  34                                int len, __wsum sum);
  35
  36 /*
  37  * the same as csum_partial_copy, but copies from user space.
  38  *
  39  * here even more important to align src and dst on a 32-bit (or even
  40  * better 64-bit) boundary
  41  */
  42
  43 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  44                                           int len, __wsum sum, int *csum_err);
  45
  46 #define csum_partial_copy_nocheck(src, dst, len, sum)   \
  47         csum_partial_copy((src), (dst), (len), (sum))
  48
  49 __sum16 ip_fast_csum(unsigned char *iph, unsigned int ihl);
  50
  51 /*
  52  *      Fold a partial checksum
  53  */
  54
  55 static inline __sum16 csum_fold(__wsum sum)
  56 {
  57         while (sum >> 16)
  58                 sum = (sum & 0xffff) + (sum >> 16);
  59         return ((~(sum << 16)) >> 16);
  60 }
  61
  62 /*
  63  * computes the checksum of the TCP/UDP pseudo-header
  64  * returns a 16-bit checksum, already complemented
  65  */
  66
  67 static inline __wsum
  68 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
  69                    unsigned short proto, __wsum sum)
  70 {
  71         unsigned int carry;
  72
  73         __asm__ ("%0 = %0 + %2;\n\t"
  74                 "CC = AC0;\n\t"
  75                 "%1 = CC;\n\t"
  76                 "%0 = %0 + %1;\n\t"
  77                 "%0 = %0 + %3;\n\t"
  78                 "CC = AC0;\n\t"
  79                 "%1 = CC;\n\t"
  80                 "%0 = %0 + %1;\n\t"
  81                 "%0 = %0 + %4;\n\t"
  82                 "CC = AC0;\n\t"
  83                 "%1 = CC;\n\t"
  84                 "%0 = %0 + %1;\n\t"
  85                 : "=d" (sum), "=&d" (carry)
  86                 : "d" (daddr), "d" (saddr), "d" ((len + proto) << 8), "0"(sum)
  87                 : "CC");
  88
  89         return (sum);
  90 }
  91
  92 static inline __sum16
  93 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
  94                   unsigned short proto, __wsum sum)
  95 {
  96         return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
  97 }
  98
  99 /*
 100  * this routine is used for miscellaneous IP-like checksums, mainly
 101  * in icmp.c
 102  */
 103
 104 extern __sum16 ip_compute_csum(const void *buff, int len);
 105
 106 #endif                          /* _BFIN_CHECKSUM_H */