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1 | /* |
2 | * Copyright (C) 2004-2006 Atmel Corporation | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License version 2 as | |
6 | * published by the Free Software Foundation. | |
7 | */ | |
8 | #ifndef __ASM_AVR32_CHECKSUM_H | |
9 | #define __ASM_AVR32_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 | unsigned int csum_partial(const unsigned char * buff, int len, | |
24 | unsigned int sum); | |
25 | ||
26 | /* | |
27 | * the same as csum_partial, but copies from src while it | |
28 | * checksums, and handles user-space pointer exceptions correctly, when needed. | |
29 | * | |
30 | * here even more important to align src and dst on a 32-bit (or even | |
31 | * better 64-bit) boundary | |
32 | */ | |
33 | unsigned int csum_partial_copy_generic(const char *src, char *dst, int len, | |
34 | int sum, int *src_err_ptr, | |
35 | int *dst_err_ptr); | |
36 | ||
37 | /* | |
38 | * Note: when you get a NULL pointer exception here this means someone | |
39 | * passed in an incorrect kernel address to one of these functions. | |
40 | * | |
41 | * If you use these functions directly please don't forget the | |
42 | * verify_area(). | |
43 | */ | |
44 | static inline | |
45 | unsigned int csum_partial_copy_nocheck(const char *src, char *dst, | |
46 | int len, int sum) | |
47 | { | |
48 | return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); | |
49 | } | |
50 | ||
51 | static inline | |
52 | unsigned int csum_partial_copy_from_user (const char __user *src, char *dst, | |
53 | int len, int sum, int *err_ptr) | |
54 | { | |
55 | return csum_partial_copy_generic((const char __force *)src, dst, len, | |
56 | sum, err_ptr, NULL); | |
57 | } | |
58 | ||
59 | /* | |
60 | * This is a version of ip_compute_csum() optimized for IP headers, | |
61 | * which always checksum on 4 octet boundaries. | |
62 | */ | |
63 | static inline unsigned short ip_fast_csum(unsigned char *iph, | |
64 | unsigned int ihl) | |
65 | { | |
66 | unsigned int sum, tmp; | |
67 | ||
68 | __asm__ __volatile__( | |
69 | " ld.w %0, %1++\n" | |
70 | " ld.w %3, %1++\n" | |
71 | " sub %2, 4\n" | |
72 | " add %0, %3\n" | |
73 | " ld.w %3, %1++\n" | |
74 | " adc %0, %0, %3\n" | |
75 | " ld.w %3, %1++\n" | |
76 | " adc %0, %0, %3\n" | |
77 | " acr %0\n" | |
78 | "1: ld.w %3, %1++\n" | |
79 | " add %0, %3\n" | |
80 | " acr %0\n" | |
81 | " sub %2, 1\n" | |
82 | " brne 1b\n" | |
83 | " lsl %3, %0, 16\n" | |
84 | " andl %0, 0\n" | |
85 | " mov %2, 0xffff\n" | |
86 | " add %0, %3\n" | |
87 | " adc %0, %0, %2\n" | |
88 | " com %0\n" | |
89 | " lsr %0, 16\n" | |
90 | : "=r"(sum), "=r"(iph), "=r"(ihl), "=r"(tmp) | |
91 | : "1"(iph), "2"(ihl) | |
92 | : "memory", "cc"); | |
93 | return sum; | |
94 | } | |
95 | ||
96 | /* | |
97 | * Fold a partial checksum | |
98 | */ | |
99 | ||
100 | static inline unsigned int csum_fold(unsigned int sum) | |
101 | { | |
102 | unsigned int tmp; | |
103 | ||
104 | asm(" bfextu %1, %0, 0, 16\n" | |
105 | " lsr %0, 16\n" | |
106 | " add %0, %1\n" | |
107 | " bfextu %1, %0, 16, 16\n" | |
108 | " add %0, %1" | |
109 | : "=&r"(sum), "=&r"(tmp) | |
110 | : "0"(sum)); | |
111 | ||
112 | return ~sum; | |
113 | } | |
114 | ||
115 | static inline unsigned long csum_tcpudp_nofold(unsigned long saddr, | |
116 | unsigned long daddr, | |
117 | unsigned short len, | |
118 | unsigned short proto, | |
119 | unsigned int sum) | |
120 | { | |
121 | asm(" add %0, %1\n" | |
122 | " adc %0, %0, %2\n" | |
123 | " adc %0, %0, %3\n" | |
124 | " acr %0" | |
125 | : "=r"(sum) | |
126 | : "r"(daddr), "r"(saddr), "r"(ntohs(len) | (proto << 16)), | |
127 | "0"(sum) | |
128 | : "cc"); | |
129 | ||
130 | return sum; | |
131 | } | |
132 | ||
133 | /* | |
134 | * computes the checksum of the TCP/UDP pseudo-header | |
135 | * returns a 16-bit checksum, already complemented | |
136 | */ | |
137 | static inline unsigned short int csum_tcpudp_magic(unsigned long saddr, | |
138 | unsigned long daddr, | |
139 | unsigned short len, | |
140 | unsigned short proto, | |
141 | unsigned int sum) | |
142 | { | |
143 | return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); | |
144 | } | |
145 | ||
146 | /* | |
147 | * this routine is used for miscellaneous IP-like checksums, mainly | |
148 | * in icmp.c | |
149 | */ | |
150 | ||
151 | static inline unsigned short ip_compute_csum(unsigned char * buff, int len) | |
152 | { | |
153 | return csum_fold(csum_partial(buff, len, 0)); | |
154 | } | |
155 | ||
156 | #endif /* __ASM_AVR32_CHECKSUM_H */ |