/*
* Checksum functions for Hexagon
*
* Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*/
/* This was derived from arch/alpha/lib/checksum.c */
#include <linux/module.h>
#include <linux/string.h>
#include <asm/byteorder.h>
#include <net/checksum.h>
#include <linux/uaccess.h>
#include <asm/intrinsics.h>
/* Vector value operations */
#define SIGN(x, y) ((0x8000ULL*x)<<y)
#define CARRY(x, y) ((0x0002ULL*x)<<y)
#define SELECT(x, y) ((0x0001ULL*x)<<y)
#define VR_NEGATE(a, b, c, d) (SIGN(a, 48) + SIGN(b, 32) + SIGN(c, 16) \
+ SIGN(d, 0))
#define VR_CARRY(a, b, c, d) (CARRY(a, 48) + CARRY(b, 32) + CARRY(c, 16) \
+ CARRY(d, 0))
#define VR_SELECT(a, b, c, d) (SELECT(a, 48) + SELECT(b, 32) + SELECT(c, 16) \
+ SELECT(d, 0))
/* optimized HEXAGON V3 intrinsic version */
static inline unsigned short from64to16(u64 x)
{
u64 sum;
sum = HEXAGON_P_vrmpyh_PP(x^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum += VR_CARRY(0, 0, 1, 0);
sum = HEXAGON_P_vrmpyh_PP(sum, VR_SELECT(0, 0, 1, 1));
return 0xFFFF & sum;
}
/*
* computes the checksum of the TCP/UDP pseudo-header
* returns a 16-bit checksum, already complemented.
*/
__sum16 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
unsigned short len, unsigned short proto,
__wsum sum)
{
return (__force __sum16)~from64to16(
(__force u64)saddr + (__force u64)daddr +
(__force u64)sum + ((len + proto) << 8));
}
__wsum csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
unsigned short len, unsigned short proto,
__wsum sum)
{
u64 result;
result = (__force u64)saddr + (__force u64)daddr +
(__force u64)sum + ((len + proto) << 8);
/* Fold down to 32-bits so we don't lose in the typedef-less
network stack. */
/* 64 to 33 */
result = (result & 0xffffffffUL) + (result >> 32);
/* 33 to 32 */
result = (result & 0xffffffffUL) + (result >> 32);
return (__force __wsum)result;
}
EXPORT_SYMBOL(csum_tcpudp_nofold);
/*
* Do a 64-bit checksum on an arbitrary memory area..
*
* This isn't a great routine, but it's not _horrible_ either. The
* inner loop could be unrolled a bit further, and there are better
* ways to do the carry, but this is reasonable.
*/
/* optimized HEXAGON intrinsic version, with over read fixed */
unsigned int do_csum(const void *voidptr, int len)
{
u64 sum0, sum1, x0, x1, *ptr8_o, *ptr8_e, *ptr8;
int i, start, mid, end, mask;
const char *ptr = voidptr;
unsigned short *ptr2;
unsigned int *ptr4;
if (len <= 0)
return 0;
start = 0xF & (16-(((int) ptr) & 0xF)) ;
mask = 0x7fffffffUL >> HEXAGON_R_cl0_R(len);
start = start & mask ;
mid = len - start;
end = mid & 0xF;
mid = mid>>4;
sum0 = mid << 18;
sum1 = 0;
if (start & 1)
sum0 += (u64) (ptr[0] << 8);
ptr2 = (unsigned short *) &ptr[start & 1];
if (start & 2)
sum1 += (u64) ptr2[0];
ptr4 = (unsigned int *) &ptr[start & 3];
if (start & 4) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
VR_SELECT(0, 0, 1, 1));
sum0 += VR_SELECT(0, 0, 1, 0);
}
ptr8 = (u64 *) &ptr[start & 7];
if (start & 8) {
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
VR_SELECT(1, 1, 1, 1));
sum1 += VR_CARRY(0, 0, 1, 0);
}
ptr8_o = (u64 *) (ptr + start);
ptr8_e = (u64 *) (ptr + start + 8);
if (mid) {
x0 = *ptr8_e; ptr8_e += 2;
x1 = *ptr8_o; ptr8_o += 2;
if (mid > 1)
for (i = 0; i < mid-1; i++) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
x0^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
x1^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
x0 = *ptr8_e; ptr8_e += 2;
x1 = *ptr8_o; ptr8_o += 2;
}
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0, x0^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1, x1^VR_NEGATE(1, 1, 1, 1),
VR_SELECT(1, 1, 1, 1));
}
ptr4 = (unsigned int *) &ptr[start + (mid * 16) + (end & 8)];
if (end & 4) {
sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
VR_SELECT(0, 0, 1, 1));
sum1 += VR_SELECT(0, 0, 1, 0);
}
ptr2 = (unsigned short *) &ptr[start + (mid * 16) + (end & 12)];
if (end & 2)
sum0 += (u64) ptr2[0];
if (end & 1)
sum1 += (u64) ptr[start + (mid * 16) + (end & 14)];
ptr8 = (u64 *) &ptr[start + (mid * 16)];
if (end & 8) {
sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
VR_SELECT(1, 1, 1, 1));
sum0 += VR_CARRY(0, 0, 1, 0);
}
sum0 = HEXAGON_P_vrmpyh_PP((sum0+sum1)^VR_NEGATE(0, 0, 0, 1),
VR_SELECT(0, 0, 1, 1));
sum0 += VR_NEGATE(0, 0, 0, 1);
sum0 = HEXAGON_P_vrmpyh_PP(sum0, VR_SELECT(0, 0, 1, 1));
if (start & 1)
sum0 = (sum0 << 8) | (0xFF & (sum0 >> 8));
return 0xFFFF & sum0;
}
/*
* copy from ds while checksumming, otherwise like csum_partial
*/
__wsum
csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
{
memcpy(dst, src, len);
return csum_partial(dst, len, sum);
}