1/* MN10300 Optimised checksumming wrappers
2 *
3 * Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
4 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public Licence
9 * as published by the Free Software Foundation; either version
10 * 2 of the Licence, or (at your option) any later version.
11 */
12#include <linux/module.h>
13#include <linux/errno.h>
14#include <asm/byteorder.h>
15#include <asm/uaccess.h>
16#include <asm/checksum.h>
17#include "internal.h"
18
19static inline unsigned short from32to16(__wsum sum)
20{
21	asm("	add	%1,%0		\n"
22	    "	addc	0xffff,%0	\n"
23	    : "=r" (sum)
24	    : "r" (sum << 16), "0" (sum & 0xffff0000)
25	    : "cc"
26	    );
27	return sum >> 16;
28}
29
30__sum16 ip_fast_csum(const void *iph, unsigned int ihl)
31{
32	return ~do_csum(iph, ihl * 4);
33}
34EXPORT_SYMBOL(ip_fast_csum);
35
36__wsum csum_partial(const void *buff, int len, __wsum sum)
37{
38	__wsum result;
39
40	result = do_csum(buff, len);
41	result += sum;
42	if (sum > result)
43		result++;
44	return result;
45}
46EXPORT_SYMBOL(csum_partial);
47
48__sum16 ip_compute_csum(const void *buff, int len)
49{
50	return ~from32to16(do_csum(buff, len));
51}
52EXPORT_SYMBOL(ip_compute_csum);
53
54__wsum csum_partial_copy(const void *src, void *dst, int len, __wsum sum)
55{
56	copy_from_user(dst, src, len);
57	return csum_partial(dst, len, sum);
58}
59EXPORT_SYMBOL(csum_partial_copy);
60
61__wsum csum_partial_copy_nocheck(const void *src, void *dst,
62				 int len, __wsum sum)
63{
64	sum = csum_partial(src, len, sum);
65	memcpy(dst, src, len);
66	return sum;
67}
68EXPORT_SYMBOL(csum_partial_copy_nocheck);
69
70__wsum csum_partial_copy_from_user(const void *src, void *dst,
71				   int len, __wsum sum,
72				   int *err_ptr)
73{
74	int missing;
75
76	missing = copy_from_user(dst, src, len);
77	if (missing) {
78		memset(dst + len - missing, 0, missing);
79		*err_ptr = -EFAULT;
80	}
81
82	return csum_partial(dst, len, sum);
83}
84EXPORT_SYMBOL(csum_partial_copy_from_user);
85
86__wsum csum_and_copy_to_user(const void *src, void *dst,
87			     int len, __wsum sum,
88			     int *err_ptr)
89{
90	int missing;
91
92	missing = copy_to_user(dst, src, len);
93	if (missing) {
94		memset(dst + len - missing, 0, missing);
95		*err_ptr = -EFAULT;
96	}
97
98	return csum_partial(src, len, sum);
99}
100EXPORT_SYMBOL(csum_and_copy_to_user);
101