1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
4 *
5 * Joern Rennecke  <joern.rennecke@embecosm.com>: Jan 2012
6 *  -Insn Scheduling improvements to csum core routines.
7 *      = csum_fold( ) largely derived from ARM version.
8 *      = ip_fast_cum( ) to have module scheduling
9 *  -gcc 4.4.x broke networking. Alias analysis needed to be primed.
10 *   worked around by adding memory clobber to ip_fast_csum( )
11 *
12 * vineetg: May 2010
13 *  -Rewrote ip_fast_cscum( ) and csum_fold( ) with fast inline asm
14 */
15
16#ifndef _ASM_ARC_CHECKSUM_H
17#define _ASM_ARC_CHECKSUM_H
18
19/*
20 *	Fold a partial checksum
21 *
22 *  The 2 swords comprising the 32bit sum are added, any carry to 16th bit
23 *  added back and final sword result inverted.
24 */
25static inline __sum16 csum_fold(__wsum s)
26{
27	unsigned int r = s << 16 | s >> 16;	/* ror */
28	s = ~s;
29	s -= r;
30	return s >> 16;
31}
32
33/*
34 *	This is a version of ip_compute_csum() optimized for IP headers,
35 *	which always checksum on 4 octet boundaries.
36 */
37static inline __sum16
38ip_fast_csum(const void *iph, unsigned int ihl)
39{
40	const void *ptr = iph;
41	unsigned int tmp, tmp2, sum;
42
43	__asm__(
44	"	ld.ab  %0, [%3, 4]		\n"
45	"	ld.ab  %2, [%3, 4]		\n"
46	"	sub    %1, %4, 2		\n"
47	"	lsr.f  lp_count, %1, 1		\n"
48	"	bcc    0f			\n"
49	"	add.f  %0, %0, %2		\n"
50	"	ld.ab  %2, [%3, 4]		\n"
51	"0:	lp     1f			\n"
52	"	ld.ab  %1, [%3, 4]		\n"
53	"	adc.f  %0, %0, %2		\n"
54	"	ld.ab  %2, [%3, 4]		\n"
55	"	adc.f  %0, %0, %1		\n"
56	"1:	adc.f  %0, %0, %2		\n"
57	"	add.cs %0,%0,1			\n"
58	: "=&r"(sum), "=r"(tmp), "=&r"(tmp2), "+&r" (ptr)
59	: "r"(ihl)
60	: "cc", "lp_count", "memory");
61
62	return csum_fold(sum);
63}
64
65/*
66 * TCP pseudo Header is 12 bytes:
67 * SA [4], DA [4], zeroes [1], Proto[1], TCP Seg(hdr+data) Len [2]
68 */
69static inline __wsum
70csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
71		   __u8 proto, __wsum sum)
72{
73	__asm__ __volatile__(
74	"	add.f %0, %0, %1	\n"
75	"	adc.f %0, %0, %2	\n"
76	"	adc.f %0, %0, %3	\n"
77	"	adc.f %0, %0, %4	\n"
78	"	adc   %0, %0, 0		\n"
79	: "+&r"(sum)
80	: "r"(saddr), "r"(daddr),
81#ifdef CONFIG_CPU_BIG_ENDIAN
82	  "r"(len),
83#else
84	  "r"(len << 8),
85#endif
86	  "r"(htons(proto))
87	: "cc");
88
89	return sum;
90}
91
92#define csum_fold csum_fold
93#define ip_fast_csum ip_fast_csum
94#define csum_tcpudp_nofold csum_tcpudp_nofold
95
96#include <asm-generic/checksum.h>
97
98#endif /* _ASM_ARC_CHECKSUM_H */
99