xref: /openbmc/linux/arch/m68k/include/asm/checksum.h (revision fd589a8f)
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 */
171