1/*
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 */
102