release/src-rt-6.x.4708/linux/linux-2.6.36/arch/m68k/include/asm/checksum.h

   1 #ifndef _M68K_CHECKSUM_H
   2 #define _M68K_CHECKSUM_H
   3
   4 #include <linux/in6.h>
   5
   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 extern __wsum csum_partial_copy_from_user(const void __user *src,
  29                                                 void *dst,
  30                                                 int len, __wsum sum,
  31                                                 int *csum_err);
  32
  33 extern __wsum csum_partial_copy_nocheck(const void *src,
  34                                               void *dst, int len,
  35                                               __wsum sum);
  36
  37
  38 #ifdef CONFIG_COLDFIRE
  39
  40 /*
  41  *      The ColdFire cores don't support all the 68k instructions used
  42  *      in the optimized checksum code below. So it reverts back to using
  43  *      more standard C coded checksums. The fast checksum code is
  44  *      significantly larger than the optimized version, so it is not
  45  *      inlined here.
  46  */
  47 __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  48
  49 static inline __sum16 csum_fold(__wsum sum)
  50 {
  51         unsigned int tmp = (__force u32)sum;
  52
  53         tmp = (tmp & 0xffff) + (tmp >> 16);
  54         tmp = (tmp & 0xffff) + (tmp >> 16);
  55
  56         return (__force __sum16)~tmp;
  57 }
  58
  59 #else
  60
  61 /*
  62  *      This is a version of ip_fast_csum() optimized for IP headers,
  63  *      which always checksum on 4 octet boundaries.
  64  */
  65 static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  66 {
  67         unsigned int sum = 0;
  68         unsigned long tmp;
  69
  70         __asm__ ("subqw #1,%2\n"
  71                  "1:\t"
  72                  "movel %1@+,%3\n\t"
  73                  "addxl %3,%0\n\t"
  74                  "dbra  %2,1b\n\t"
  75                  "movel %0,%3\n\t"
  76                  "swap  %3\n\t"
  77                  "addxw %3,%0\n\t"
  78                  "clrw  %3\n\t"
  79                  "addxw %3,%0\n\t"
  80                  : "=d" (sum), "=&a" (iph), "=&d" (ihl), "=&d" (tmp)
  81                  : "0" (sum), "1" (iph), "2" (ihl)
  82                  : "memory");
  83         return (__force __sum16)~sum;
  84 }
  85
  86 static inline __sum16 csum_fold(__wsum sum)
  87 {
  88         unsigned int tmp = (__force u32)sum;
  89
  90         __asm__("swap %1\n\t"
  91                 "addw %1, %0\n\t"
  92                 "clrw %1\n\t"
  93                 "addxw %1, %0"
  94                 : "=&d" (sum), "=&d" (tmp)
  95                 : "0" (sum), "1" (tmp));
  96
  97         return (__force __sum16)~sum;
  98 }
  99
 100 #endif /* CONFIG_COLDFIRE */
 101
 102 static inline __wsum
 103 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
 104                   unsigned short proto, __wsum sum)
 105 {
 106         __asm__ ("addl  %2,%0\n\t"
 107                  "addxl %3,%0\n\t"
 108                  "addxl %4,%0\n\t"
 109                  "clrl %1\n\t"
 110                  "addxl %1,%0"
 111                  : "=&d" (sum), "=d" (saddr)
 112                  : "g" (daddr), "1" (saddr), "d" (len + proto),
 113                    "0" (sum));
 114         return sum;
 115 }
 116
 117
 118 /*
 119  * computes the checksum of the TCP/UDP pseudo-header
 120  * returns a 16-bit checksum, already complemented
 121  */
 122 static inline __sum16
 123 csum_tcpudp_magic(__be32 saddr, __be32 daddr, unsigned short len,
 124                   unsigned short proto, __wsum sum)
 125 {
 126         return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum));
 127 }
 128
 129 /*
 130  * this routine is used for miscellaneous IP-like checksums, mainly
 131  * in icmp.c
 132  */
 133
 134 static inline __sum16 ip_compute_csum(const void *buff, int len)
 135 {
 136         return csum_fold (csum_partial(buff, len, 0));
 137 }
 138
 139 #define _HAVE_ARCH_IPV6_CSUM
 140 static __inline__ __sum16
 141 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
 142                 __u32 len, unsigned short proto, __wsum sum)
 143 {
 144         register unsigned long tmp;
 145         __asm__("addl %2@,%0\n\t"
 146                 "movel %2@(4),%1\n\t"
 147                 "addxl %1,%0\n\t"
 148                 "movel %2@(8),%1\n\t"
 149                 "addxl %1,%0\n\t"
 150                 "movel %2@(12),%1\n\t"
 151                 "addxl %1,%0\n\t"
 152                 "movel %3@,%1\n\t"
 153                 "addxl %1,%0\n\t"
 154                 "movel %3@(4),%1\n\t"
 155                 "addxl %1,%0\n\t"
 156                 "movel %3@(8),%1\n\t"
 157                 "addxl %1,%0\n\t"
 158                 "movel %3@(12),%1\n\t"
 159                 "addxl %1,%0\n\t"
 160                 "addxl %4,%0\n\t"
 161                 "clrl %1\n\t"
 162                 "addxl %1,%0"
 163                 : "=&d" (sum), "=&d" (tmp)
 164                 : "a" (saddr), "a" (daddr), "d" (len + proto),
 165                   "0" (sum));
 166
 167         return csum_fold(sum);
 168 }
 169
 170 #endif /* _M68K_CHECKSUM_H */