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