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Vineet Guptaca15c8e2013-01-18 15:12:17 +05301/*
2 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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 * Joern Rennecke <joern.rennecke@embecosm.com>: Jan 2012
9 * -Insn Scheduling improvements to csum core routines.
10 * = csum_fold( ) largely derived from ARM version.
11 * = ip_fast_cum( ) to have module scheduling
12 * -gcc 4.4.x broke networking. Alias analysis needed to be primed.
13 * worked around by adding memory clobber to ip_fast_csum( )
14 *
15 * vineetg: May 2010
16 * -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
17 */
18
19#ifndef _ASM_ARC_CHECKSUM_H
20#define _ASM_ARC_CHECKSUM_H
21
22/*
23 * Fold a partial checksum
24 *
25 * The 2 swords comprising the 32bit sum are added, any carry to 16th bit
26 * added back and final sword result inverted.
27 */
28static inline __sum16 csum_fold(__wsum s)
29{
30 unsigned r = s << 16 | s >> 16; /* ror */
31 s = ~s;
32 s -= r;
33 return s >> 16;
34}
35
36/*
37 * This is a version of ip_compute_csum() optimized for IP headers,
38 * which always checksum on 4 octet boundaries.
39 */
40static inline __sum16
41ip_fast_csum(const void *iph, unsigned int ihl)
42{
43 const void *ptr = iph;
44 unsigned int tmp, tmp2, sum;
45
46 __asm__(
47 " ld.ab %0, [%3, 4] \n"
48 " ld.ab %2, [%3, 4] \n"
49 " sub %1, %4, 2 \n"
50 " lsr.f lp_count, %1, 1 \n"
51 " bcc 0f \n"
52 " add.f %0, %0, %2 \n"
53 " ld.ab %2, [%3, 4] \n"
54 "0: lp 1f \n"
55 " ld.ab %1, [%3, 4] \n"
56 " adc.f %0, %0, %2 \n"
57 " ld.ab %2, [%3, 4] \n"
58 " adc.f %0, %0, %1 \n"
59 "1: adc.f %0, %0, %2 \n"
60 " add.cs %0,%0,1 \n"
61 : "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
62 : "r"(ihl)
63 : "cc", "lp_count", "memory");
64
65 return csum_fold(sum);
66}
67
68/*
69 * TCP pseudo Header is 12 bytes:
70 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
71 */
72static inline __wsum
73csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
74 unsigned short proto, __wsum sum)
75{
76 __asm__ __volatile__(
77 " add.f %0, %0, %1 \n"
78 " adc.f %0, %0, %2 \n"
79 " adc.f %0, %0, %3 \n"
80 " adc.f %0, %0, %4 \n"
81 " adc %0, %0, 0 \n"
82 : "+&r"(sum)
83 : "r"(saddr), "r"(daddr),
84#ifdef CONFIG_CPU_BIG_ENDIAN
85 "r"(len),
86#else
87 "r"(len << 8),
88#endif
89 "r"(htons(proto))
90 : "cc");
91
92 return sum;
93}
94
95#define csum_fold csum_fold
96#define ip_fast_csum ip_fast_csum
97#define csum_tcpudp_nofold csum_tcpudp_nofold
98
99#include <asm-generic/checksum.h>
100
101#endif /* _ASM_ARC_CHECKSUM_H */