arch/frv/include/asm/checksum.h

   1 /* checksum.h: FRV checksumming
   2  *
   3  * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #ifndef _ASM_CHECKSUM_H
  13 #define _ASM_CHECKSUM_H
  14
  15 #include <linux/in6.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 __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 __wsum csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum);
  39
  40 /*
  41  * the same as csum_partial_copy, but copies from user space.
  42  *
  43  * here even more important to align src and dst on a 32-bit (or even
  44  * better 64-bit) boundary
  45  */
  46 extern __wsum csum_partial_copy_from_user(const void __user *src, void *dst,
  47                                                 int len, __wsum sum, int *csum_err);
  48
  49 /*
  50  *      This is a version of ip_compute_csum() optimized for IP headers,
  51  *      which always checksum on 4 octet boundaries.
  52  *
  53  */
  54 static inline
  55 __sum16 ip_fast_csum(const void *iph, unsigned int ihl)
  56 {
  57         unsigned int tmp, inc, sum = 0;
  58
  59         asm("   addcc           gr0,gr0,gr0,icc0\n" /* clear icc0.C */
  60             "   subi            %1,#4,%1        \n"
  61             "0:                                 \n"
  62             "   ldu.p           @(%1,%3),%4     \n"
  63             "   subicc          %2,#1,%2,icc1   \n"
  64             "   addxcc.p        %4,%0,%0,icc0   \n"
  65             "   bhi             icc1,#2,0b      \n"
  66
  67             /* fold the 33-bit result into 16-bits */
  68             "   addxcc          gr0,%0,%0,icc0  \n"
  69             "   srli            %0,#16,%1       \n"
  70             "   sethi           #0,%0           \n"
  71             "   add             %1,%0,%0        \n"
  72             "   srli            %0,#16,%1       \n"
  73             "   add             %1,%0,%0        \n"
  74
  75             : "=r" (sum), "=r" (iph), "=r" (ihl), "=r" (inc), "=&r"(tmp)
  76             : "0" (sum), "1" (iph), "2" (ihl), "3" (4),
  77             "m"(*(volatile struct { int _[100]; } *)iph)
  78             : "icc0", "icc1", "memory"
  79             );
  80
  81         return (__force __sum16)~sum;
  82 }
  83
  84 /*
  85  *      Fold a partial checksum
  86  */
  87 static inline __sum16 csum_fold(__wsum sum)
  88 {
  89         unsigned int tmp;
  90
  91         asm("   srli            %0,#16,%1       \n"
  92             "   sethi           #0,%0           \n"
  93             "   add             %1,%0,%0        \n"
  94             "   srli            %0,#16,%1       \n"
  95             "   add             %1,%0,%0        \n"
  96             : "=r"(sum), "=&r"(tmp)
  97             : "0"(sum)
  98             );
  99
 100         return (__force __sum16)~sum;
 101 }
 102
 103 /*
 104  * computes the checksum of the TCP/UDP pseudo-header
 105  * returns a 16-bit checksum, already complemented
 106  */
 107 static inline __wsum
 108 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
 109                   unsigned short proto, __wsum sum)
 110 {
 111         asm("   addcc           %1,%0,%0,icc0   \n"
 112             "   addxcc          %2,%0,%0,icc0   \n"
 113             "   addxcc          %3,%0,%0,icc0   \n"
 114             "   addxcc          gr0,%0,%0,icc0  \n"
 115             : "=r" (sum)
 116             : "r" (daddr), "r" (saddr), "r" (len + proto), "0"(sum)
 117             : "icc0"
 118             );
 119         return sum;
 120 }
 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 extern __sum16 ip_compute_csum(const void *buff, int len);
 134
 135 #define _HAVE_ARCH_IPV6_CSUM
 136 static inline __sum16
 137 csum_ipv6_magic(const struct in6_addr *saddr, const struct in6_addr *daddr,
 138                 __u32 len, unsigned short proto, __wsum sum)
 139 {
 140         unsigned long tmp, tmp2;
 141
 142         asm("   addcc           %2,%0,%0,icc0   \n"
 143
 144             /* add up the source addr */
 145             "   ldi             @(%3,0),%1      \n"
 146             "   addxcc          %1,%0,%0,icc0   \n"
 147             "   ldi             @(%3,4),%2      \n"
 148             "   addxcc          %2,%0,%0,icc0   \n"
 149             "   ldi             @(%3,8),%1      \n"
 150             "   addxcc          %1,%0,%0,icc0   \n"
 151             "   ldi             @(%3,12),%2     \n"
 152             "   addxcc          %2,%0,%0,icc0   \n"
 153
 154             /* add up the dest addr */
 155             "   ldi             @(%4,0),%1      \n"
 156             "   addxcc          %1,%0,%0,icc0   \n"
 157             "   ldi             @(%4,4),%2      \n"
 158             "   addxcc          %2,%0,%0,icc0   \n"
 159             "   ldi             @(%4,8),%1      \n"
 160             "   addxcc          %1,%0,%0,icc0   \n"
 161             "   ldi             @(%4,12),%2     \n"
 162             "   addxcc          %2,%0,%0,icc0   \n"
 163
 164             /* fold the 33-bit result into 16-bits */
 165             "   addxcc          gr0,%0,%0,icc0  \n"
 166             "   srli            %0,#16,%1       \n"
 167             "   sethi           #0,%0           \n"
 168             "   add             %1,%0,%0        \n"
 169             "   srli            %0,#16,%1       \n"
 170             "   add             %1,%0,%0        \n"
 171
 172             : "=r" (sum), "=&r" (tmp), "=r" (tmp2)
 173             : "r" (saddr), "r" (daddr), "0" (sum), "2" (len + proto)
 174             : "icc0"
 175             );
 176
 177         return (__force __sum16)~sum;
 178 }
 179
 180 #endif /* _ASM_CHECKSUM_H */