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__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, and handles user-space pointer exceptions correctly, when needed. 28 * 29 * here even more important to align src and dst on a 32-bit (or even 30 * better 64-bit) boundary 31 */ 32__wsum csum_partial_copy_generic(const void *src, void *dst, int len, 33 __wsum sum, int *src_err_ptr, 34 int *dst_err_ptr); 35 36/* 37 * Note: when you get a NULL pointer exception here this means someone 38 * passed in an incorrect kernel address to one of these functions. 39 * 40 * If you use these functions directly please don't forget the 41 * access_ok(). 42 */ 43static inline 44__wsum csum_partial_copy_nocheck(const void *src, void *dst, 45 int len, __wsum sum) 46{ 47 return csum_partial_copy_generic(src, dst, len, sum, NULL, NULL); 48} 49 50static inline 51__wsum csum_partial_copy_from_user(const void __user *src, void *dst, 52 int len, __wsum sum, int *err_ptr) 53{ 54 return csum_partial_copy_generic((const void __force *)src, dst, len, 55 sum, err_ptr, NULL); 56} 57 58/* 59 * This is a version of ip_compute_csum() optimized for IP headers, 60 * which always checksum on 4 octet boundaries. 61 */ 62static inline __sum16 ip_fast_csum(const void *iph, unsigned int ihl) 63{ 64 unsigned int sum, tmp; 65 66 __asm__ __volatile__( 67 " ld.w %0, %1++\n" 68 " ld.w %3, %1++\n" 69 " sub %2, 4\n" 70 " add %0, %3\n" 71 " ld.w %3, %1++\n" 72 " adc %0, %0, %3\n" 73 " ld.w %3, %1++\n" 74 " adc %0, %0, %3\n" 75 " acr %0\n" 76 "1: ld.w %3, %1++\n" 77 " add %0, %3\n" 78 " acr %0\n" 79 " sub %2, 1\n" 80 " brne 1b\n" 81 " lsl %3, %0, 16\n" 82 " andl %0, 0\n" 83 " mov %2, 0xffff\n" 84 " add %0, %3\n" 85 " adc %0, %0, %2\n" 86 " com %0\n" 87 " lsr %0, 16\n" 88 : "=r"(sum), "=r"(iph), "=r"(ihl), "=r"(tmp) 89 : "1"(iph), "2"(ihl) 90 : "memory", "cc"); 91 return (__force __sum16)sum; 92} 93 94/* 95 * Fold a partial checksum 96 */ 97 98static inline __sum16 csum_fold(__wsum sum) 99{ 100 unsigned int tmp; 101 102 asm(" bfextu %1, %0, 0, 16\n" 103 " lsr %0, 16\n" 104 " add %0, %1\n" 105 " bfextu %1, %0, 16, 16\n" 106 " add %0, %1" 107 : "=&r"(sum), "=&r"(tmp) 108 : "0"(sum)); 109 110 return (__force __sum16)~sum; 111} 112 113static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr, 114 unsigned short len, 115 unsigned short proto, 116 __wsum sum) 117{ 118 asm(" add %0, %1\n" 119 " adc %0, %0, %2\n" 120 " adc %0, %0, %3\n" 121 " acr %0" 122 : "=r"(sum) 123 : "r"(daddr), "r"(saddr), "r"(len + proto), 124 "0"(sum) 125 : "cc"); 126 127 return sum; 128} 129 130/* 131 * computes the checksum of the TCP/UDP pseudo-header 132 * returns a 16-bit checksum, already complemented 133 */ 134static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr, 135 unsigned short len, 136 unsigned short proto, 137 __wsum sum) 138{ 139 return csum_fold(csum_tcpudp_nofold(saddr,daddr,len,proto,sum)); 140} 141 142/* 143 * this routine is used for miscellaneous IP-like checksums, mainly 144 * in icmp.c 145 */ 146 147static inline __sum16 ip_compute_csum(const void *buff, int len) 148{ 149 return csum_fold(csum_partial(buff, len, 0)); 150} 151 152#endif /* __ASM_AVR32_CHECKSUM_H */ 153