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/*-
* Copyright (c) 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Matt Thomas of 3am Software Foundry.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: cpu_in_cksum_neon.c,v 1.1 2012/12/17 00:44:03 matt Exp $");
#include <sys/param.h>
#include <sys/cpu.h>
#include <sys/mbuf.h>
#include <netinet/in.h>
#include <netinet/ip.h>
uint32_t cpu_in_cksum_neon(const void *, size_t);
uint32_t cpu_in_cksum_neon_v4hdr(const void *);
int
cpu_in_cksum(struct mbuf *m, int len, int off, uint32_t initial_sum)
{
uint32_t csum = initial_sum;
int odd = 0;
/*
* Taken control of the NEON PCU.
*/
vfp_hijack();
/*
* Fast path for the normal ip_header
*/
if (off == 0
&& csum == 0
&& len == sizeof(struct ip)
&& ((uintptr_t)m->m_data & 3) == 0
&& m->m_len >= len) {
csum = cpu_in_cksum_neon_v4hdr(m->m_data);
/*
* We are now down with NEON.
*/
vfp_surrender();
if (csum == 0x10000) /* note 0x10000 - 0xffff == 1 */
return 1;
return csum == 0 ? 0xffff : csum; /* never return 0. */
}
/*
* Skip the initial mbufs
*/
while (m->m_len >= off) {
m = m->m_next;
off -= m->m_len;
KASSERT(m != NULL);
}
for (; len > 0; m = m->m_next, off = 0) {
KASSERT(m != NULL);
int dlen = MIN(m->m_len - off, len);
const void *dptr = m->m_data + off;
/*
* This routine will add based on the memory layout so
* if the previous len was odd or the this buffer starts
* on an odd address, shift the csum by 8 so its properly
* aligned. It will be taken care of when we do the final
* checksum fold.
*/
uint32_t tmpsum = cpu_in_cksum_neon(dptr, dlen);
if (odd ^ ((uint32_t)dptr & 1))
tmpsum <<= 8;
/*
* Accumulate checksum, folding will be done later
*/
csum += tmpsum;
odd ^= dlen & 1;
len -= dlen;
}
/*
* We are now down with NEON.
*/
vfp_surrender();
/*
* Time to fold the checksum
*/
csum = (csum >> 16) + (csum & 0xffff);
/*
* Now it could be 0x1xxxx so fold again
*/
csum = (csum >> 16) + (csum & 0xffff);
KASSERT(csum <= 0x10000);
if (csum == 0x10000) /* note 0x10000 - 0xffff == 1 */
return 1;
return csum == 0 ? 0xffff : csum; /* never return 0. */
}
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