arch/hexagon/lib/checksum.c

   1 /*
   2  * Checksum functions for Hexagon
   3  *
   4  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 and
   8  * only version 2 as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  18  * 02110-1301, USA.
  19  */
  20
  21 /*  This was derived from arch/alpha/lib/checksum.c  */
  22
  23
  24 #include <linux/module.h>
  25 #include <linux/string.h>
  26
  27 #include <asm/byteorder.h>
  28 #include <net/checksum.h>
  29 #include <linux/uaccess.h>
  30 #include <asm/intrinsics.h>
  31
  32
  33 /*  Vector value operations  */
  34 #define SIGN(x, y)      ((0x8000ULL*x)<<y)
  35 #define CARRY(x, y)     ((0x0002ULL*x)<<y)
  36 #define SELECT(x, y)    ((0x0001ULL*x)<<y)
  37
  38 #define VR_NEGATE(a, b, c, d)   (SIGN(a, 48) + SIGN(b, 32) + SIGN(c, 16) \
  39         + SIGN(d, 0))
  40 #define VR_CARRY(a, b, c, d)    (CARRY(a, 48) + CARRY(b, 32) + CARRY(c, 16) \
  41         + CARRY(d, 0))
  42 #define VR_SELECT(a, b, c, d)   (SELECT(a, 48) + SELECT(b, 32) + SELECT(c, 16) \
  43         + SELECT(d, 0))
  44
  45
  46 /* optimized HEXAGON V3 intrinsic version */
  47 static inline unsigned short from64to16(u64 x)
  48 {
  49         u64 sum;
  50
  51         sum = HEXAGON_P_vrmpyh_PP(x^VR_NEGATE(1, 1, 1, 1),
  52                              VR_SELECT(1, 1, 1, 1));
  53         sum += VR_CARRY(0, 0, 1, 0);
  54         sum = HEXAGON_P_vrmpyh_PP(sum, VR_SELECT(0, 0, 1, 1));
  55
  56         return 0xFFFF & sum;
  57 }
  58
  59 /*
  60  * computes the checksum of the TCP/UDP pseudo-header
  61  * returns a 16-bit checksum, already complemented.
  62  */
  63 __sum16 csum_tcpudp_magic(unsigned long saddr, unsigned long daddr,
  64                           unsigned short len, unsigned short proto,
  65                           __wsum sum)
  66 {
  67         return (__force __sum16)~from64to16(
  68                 (__force u64)saddr + (__force u64)daddr +
  69                 (__force u64)sum + ((len + proto) << 8));
  70 }
  71
  72 __wsum csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
  73                           unsigned short len, unsigned short proto,
  74                           __wsum sum)
  75 {
  76         u64 result;
  77
  78         result = (__force u64)saddr + (__force u64)daddr +
  79                  (__force u64)sum + ((len + proto) << 8);
  80
  81         /* Fold down to 32-bits so we don't lose in the typedef-less
  82            network stack.  */
  83         /* 64 to 33 */
  84         result = (result & 0xffffffffUL) + (result >> 32);
  85         /* 33 to 32 */
  86         result = (result & 0xffffffffUL) + (result >> 32);
  87         return (__force __wsum)result;
  88 }
  89 EXPORT_SYMBOL(csum_tcpudp_nofold);
  90
  91 /*
  92  * Do a 64-bit checksum on an arbitrary memory area..
  93  *
  94  * This isn't a great routine, but it's not _horrible_ either. The
  95  * inner loop could be unrolled a bit further, and there are better
  96  * ways to do the carry, but this is reasonable.
  97  */
  98
  99 /* optimized HEXAGON intrinsic version, with over read fixed */
 100 unsigned int do_csum(const void *voidptr, int len)
 101 {
 102         u64 sum0, sum1, x0, x1, *ptr8_o, *ptr8_e, *ptr8;
 103         int i, start, mid, end, mask;
 104         const char *ptr = voidptr;
 105         unsigned short *ptr2;
 106         unsigned int *ptr4;
 107
 108         if (len <= 0)
 109                 return 0;
 110
 111         start = 0xF & (16-(((int) ptr) & 0xF)) ;
 112         mask  = 0x7fffffffUL >> HEXAGON_R_cl0_R(len);
 113         start = start & mask ;
 114
 115         mid = len - start;
 116         end = mid & 0xF;
 117         mid = mid>>4;
 118         sum0 = mid << 18;
 119         sum1 = 0;
 120
 121         if (start & 1)
 122                 sum0 += (u64) (ptr[0] << 8);
 123         ptr2 = (unsigned short *) &ptr[start & 1];
 124         if (start & 2)
 125                 sum1 += (u64) ptr2[0];
 126         ptr4 = (unsigned int *) &ptr[start & 3];
 127         if (start & 4) {
 128                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 129                         VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
 130                         VR_SELECT(0, 0, 1, 1));
 131                 sum0 += VR_SELECT(0, 0, 1, 0);
 132         }
 133         ptr8 = (u64 *) &ptr[start & 7];
 134         if (start & 8) {
 135                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 136                         VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
 137                         VR_SELECT(1, 1, 1, 1));
 138                 sum1 += VR_CARRY(0, 0, 1, 0);
 139         }
 140         ptr8_o = (u64 *) (ptr + start);
 141         ptr8_e = (u64 *) (ptr + start + 8);
 142
 143         if (mid) {
 144                 x0 = *ptr8_e; ptr8_e += 2;
 145                 x1 = *ptr8_o; ptr8_o += 2;
 146                 if (mid > 1)
 147                         for (i = 0; i < mid-1; i++) {
 148                                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 149                                         x0^VR_NEGATE(1, 1, 1, 1),
 150                                         VR_SELECT(1, 1, 1, 1));
 151                                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 152                                         x1^VR_NEGATE(1, 1, 1, 1),
 153                                         VR_SELECT(1, 1, 1, 1));
 154                                 x0 = *ptr8_e; ptr8_e += 2;
 155                                 x1 = *ptr8_o; ptr8_o += 2;
 156                         }
 157                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0, x0^VR_NEGATE(1, 1, 1, 1),
 158                         VR_SELECT(1, 1, 1, 1));
 159                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1, x1^VR_NEGATE(1, 1, 1, 1),
 160                         VR_SELECT(1, 1, 1, 1));
 161         }
 162
 163         ptr4 = (unsigned int *) &ptr[start + (mid * 16) + (end & 8)];
 164         if (end & 4) {
 165                 sum1 = HEXAGON_P_vrmpyhacc_PP(sum1,
 166                         VR_NEGATE(0, 0, 1, 1)^((u64)ptr4[0]),
 167                         VR_SELECT(0, 0, 1, 1));
 168                 sum1 += VR_SELECT(0, 0, 1, 0);
 169         }
 170         ptr2 = (unsigned short *) &ptr[start + (mid * 16) + (end & 12)];
 171         if (end & 2)
 172                 sum0 += (u64) ptr2[0];
 173
 174         if (end & 1)
 175                 sum1 += (u64) ptr[start + (mid * 16) + (end & 14)];
 176
 177         ptr8 = (u64 *) &ptr[start + (mid * 16)];
 178         if (end & 8) {
 179                 sum0 = HEXAGON_P_vrmpyhacc_PP(sum0,
 180                         VR_NEGATE(1, 1, 1, 1)^(ptr8[0]),
 181                         VR_SELECT(1, 1, 1, 1));
 182                 sum0 += VR_CARRY(0, 0, 1, 0);
 183         }
 184         sum0 = HEXAGON_P_vrmpyh_PP((sum0+sum1)^VR_NEGATE(0, 0, 0, 1),
 185                 VR_SELECT(0, 0, 1, 1));
 186         sum0 += VR_NEGATE(0, 0, 0, 1);
 187         sum0 = HEXAGON_P_vrmpyh_PP(sum0, VR_SELECT(0, 0, 1, 1));
 188
 189         if (start & 1)
 190                 sum0 = (sum0 << 8) | (0xFF & (sum0 >> 8));
 191
 192         return 0xFFFF & sum0;
 193 }
 194
 195 /*
 196  * copy from ds while checksumming, otherwise like csum_partial
 197  */
 198 __wsum
 199 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 200 {
 201         memcpy(dst, src, len);
 202         return csum_partial(dst, len, sum);
 203 }