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// SPDX-License-Identifier: GPL-2.0-only
/*
* Accelerated CRC64 (NVMe) using ARM NEON C intrinsics
*/
#include <linux/types.h>
#include <asm/neon-intrinsics.h>
#include "crc64-neon.h"
u64 crc64_nvme_neon(u64 crc, const u8 *p, size_t len);
/* x^191 mod G, x^127 mod G */
static const u64 fold_consts_val[2] = { 0xeadc41fd2ba3d420ULL,
0x21e9761e252621acULL };
/* floor(x^127 / G), (G - x^64) / x */
static const u64 bconsts_val[2] = { 0x27ecfa329aef9f77ULL,
0x34d926535897936aULL };
u64 crc64_nvme_neon(u64 crc, const u8 *p, size_t len)
{
uint64x2_t fold_consts = vld1q_u64(fold_consts_val);
uint64x2_t v0 = { crc, 0 };
uint64x2_t zero = { };
for (;;) {
v0 ^= vreinterpretq_u64_u8(vld1q_u8(p));
p += 16;
len -= 16;
if (len < 16)
break;
v0 = pmull64(fold_consts, v0) ^ pmull64_high(fold_consts, v0);
}
/* Multiply the 128-bit value by x^64 and reduce it back to 128 bits. */
v0 = vextq_u64(v0, zero, 1) ^ pmull64_hi_lo(fold_consts, v0);
/* Final Barrett reduction */
uint64x2_t bconsts = vld1q_u64(bconsts_val);
uint64x2_t final = pmull64(bconsts, v0);
v0 ^= vextq_u64(zero, final, 1) ^ pmull64_hi_lo(bconsts, final);
return vgetq_lane_u64(v0, 1);
}
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