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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/cris/arch-v10/lib/old_checksum.c
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/*

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 * INET		An implementation of the TCP/IP protocol suite for the LINUX

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 *		operating system.  INET is implemented using the  BSD Socket

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 *		interface as the means of communication with the user level.

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 *

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 *		IP/TCP/UDP checksumming routines

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 *

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 * Authors:	Jorge Cwik, <[email protected]>

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 *		Arnt Gulbrandsen, <[email protected]>

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 *		Tom May, <[email protected]>

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 *		Lots of code moved from tcp.c and ip.c; see those files

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 *		for more names.

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 *

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 *		This program is free software; you can redistribute it and/or

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 *		modify it under the terms of the GNU General Public License

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 *		as published by the Free Software Foundation; either version

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 *		2 of the License, or (at your option) any later version.

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 */

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#include <net/checksum.h>

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#include <net/module.h>

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#undef PROFILE_CHECKSUM

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#ifdef PROFILE_CHECKSUM

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/* these are just for profiling the checksum code with an oscillioscope.. uh */

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#if 0

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#define BITOFF *((unsigned char *)0xb0000030) = 0xff

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#define BITON *((unsigned char *)0xb0000030) = 0x0

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#endif

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#include <asm/io.h>

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#define CBITON LED_ACTIVE_SET(1)

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#define CBITOFF LED_ACTIVE_SET(0)

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#define BITOFF

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#define BITON

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#else

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#define BITOFF

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#define BITON

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#define CBITOFF

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#define CBITON

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#endif

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/*

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 * computes a partial checksum, e.g. for TCP/UDP fragments

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 */

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#include <asm/delay.h>

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__wsum csum_partial(const void *p, int len, __wsum __sum)

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{

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	u32 sum = (__force u32)__sum;

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	const u16 *buff = p;

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	/*

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	* Experiments with ethernet and slip connections show that buff

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	* is aligned on either a 2-byte or 4-byte boundary.

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	*/

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	const void *endMarker = p + len;

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	const void *marker = endMarker - (len % 16);

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#if 0

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	if((int)buff & 0x3)

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		printk("unaligned buff %p\n", buff);

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	__delay(900); /* extra delay of 90 us to test performance hit */

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#endif

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	BITON;

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	while (buff < marker) {

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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		sum += *buff++;

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	}

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	marker = endMarker - (len % 2);

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	while (buff < marker)

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		sum += *buff++;

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	if (endMarker > buff)

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		sum += *(const u8 *)buff;	/* add extra byte separately */

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	BITOFF;

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	return (__force __wsum)sum;

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}

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EXPORT_SYMBOL(csum_partial);

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