// SPDX-License-Identifier: GPL-2.0-only
/*
 * Accelerated CRC32(C) using ARM CRC, NEON and Crypto Extensions instructions
 *
 * Copyright (C) 2016 Linaro Ltd <ard.biesheuvel@linaro.org>
 */

#include <linux/cpufeature.h>

#include <asm/hwcap.h>
#include <asm/simd.h>

static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_crc32);
static __ro_after_init DEFINE_STATIC_KEY_FALSE(have_pmull);

#define PMULL_MIN_LEN   64      /* min size of buffer for pmull functions */

asmlinkage u32 crc32_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32_armv8_le(u32 init_crc, const u8 buf[], u32 len);

asmlinkage u32 crc32c_pmull_le(const u8 buf[], u32 len, u32 init_crc);
asmlinkage u32 crc32c_armv8_le(u32 init_crc, const u8 buf[], u32 len);

static inline u32 crc32_le_scalar(u32 crc, const u8 *p, size_t len)
{
        if (static_branch_likely(&have_crc32))
                return crc32_armv8_le(crc, p, len);
        return crc32_le_base(crc, p, len);
}

static inline u32 crc32_le_arch(u32 crc, const u8 *p, size_t len)
{
        if (len >= PMULL_MIN_LEN + 15 &&
            static_branch_likely(&have_pmull) && likely(may_use_simd())) {
                size_t n = -(uintptr_t)p & 15;

                /* align p to 16-byte boundary */
                if (n) {
                        crc = crc32_le_scalar(crc, p, n);
                        p += n;
                        len -= n;
                }
                n = round_down(len, 16);
                scoped_ksimd()
                        crc = crc32_pmull_le(p, n, crc);
                p += n;
                len -= n;
        }
        return crc32_le_scalar(crc, p, len);
}

static inline u32 crc32c_scalar(u32 crc, const u8 *p, size_t len)
{
        if (static_branch_likely(&have_crc32))
                return crc32c_armv8_le(crc, p, len);
        return crc32c_base(crc, p, len);
}

static inline u32 crc32c_arch(u32 crc, const u8 *p, size_t len)
{
        if (len >= PMULL_MIN_LEN + 15 &&
            static_branch_likely(&have_pmull) && likely(may_use_simd())) {
                size_t n = -(uintptr_t)p & 15;

                /* align p to 16-byte boundary */
                if (n) {
                        crc = crc32c_scalar(crc, p, n);
                        p += n;
                        len -= n;
                }
                n = round_down(len, 16);
                scoped_ksimd()
                        crc = crc32c_pmull_le(p, n, crc);
                p += n;
                len -= n;
        }
        return crc32c_scalar(crc, p, len);
}

#define crc32_be_arch crc32_be_base /* not implemented on this arch */

#define crc32_mod_init_arch crc32_mod_init_arch
static void crc32_mod_init_arch(void)
{
        if (elf_hwcap2 & HWCAP2_CRC32)
                static_branch_enable(&have_crc32);
        if (elf_hwcap2 & HWCAP2_PMULL)
                static_branch_enable(&have_pmull);
}

static inline u32 crc32_optimizations_arch(void)
{
        if (elf_hwcap2 & (HWCAP2_CRC32 | HWCAP2_PMULL))
                return CRC32_LE_OPTIMIZATION | CRC32C_OPTIMIZATION;
        return 0;
}