/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
 */

#include <linux/export.h>
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>

.section .noinstr.text, "ax"

SYM_FUNC_START(memcpy)
        /*
         * Some CPUs support hardware unaligned access
         */
        ALTERNATIVE     "b __memcpy_generic", \
                        "b __memcpy_fast", CPU_FEATURE_UAL
SYM_FUNC_END(memcpy)
SYM_FUNC_ALIAS(__memcpy, memcpy)

EXPORT_SYMBOL(memcpy)
EXPORT_SYMBOL(__memcpy)

_ASM_NOKPROBE(memcpy)
_ASM_NOKPROBE(__memcpy)

/*
 * void *__memcpy_generic(void *dst, const void *src, size_t n)
 *
 * a0: dst
 * a1: src
 * a2: n
 */
SYM_FUNC_START(__memcpy_generic)
        move    a3, a0
        beqz    a2, 2f

1:      ld.b    t0, a1, 0
        st.b    t0, a0, 0
        addi.d  a0, a0, 1
        addi.d  a1, a1, 1
        addi.d  a2, a2, -1
        bgt     a2, zero, 1b

2:      move    a0, a3
        jr      ra
SYM_FUNC_END(__memcpy_generic)
_ASM_NOKPROBE(__memcpy_generic)

        .align  5
SYM_FUNC_START_NOALIGN(__memcpy_small)
        pcaddi  t0, 8
        slli.d  a2, a2, 5
        add.d   t0, t0, a2
        jr      t0

        .align  5
0:      jr      ra

        .align  5
1:      ld.b    t0, a1, 0
        st.b    t0, a0, 0
        jr      ra

        .align  5
2:      ld.h    t0, a1, 0
        st.h    t0, a0, 0
        jr      ra

        .align  5
3:      ld.h    t0, a1, 0
        ld.b    t1, a1, 2
        st.h    t0, a0, 0
        st.b    t1, a0, 2
        jr      ra

        .align  5
4:      ld.w    t0, a1, 0
        st.w    t0, a0, 0
        jr      ra

        .align  5
5:      ld.w    t0, a1, 0
        ld.b    t1, a1, 4
        st.w    t0, a0, 0
        st.b    t1, a0, 4
        jr      ra

        .align  5
6:      ld.w    t0, a1, 0
        ld.h    t1, a1, 4
        st.w    t0, a0, 0
        st.h    t1, a0, 4
        jr      ra

        .align  5
7:      ld.w    t0, a1, 0
        ld.w    t1, a1, 3
        st.w    t0, a0, 0
        st.w    t1, a0, 3
        jr      ra

        .align  5
8:      ld.d    t0, a1, 0
        st.d    t0, a0, 0
        jr      ra
SYM_FUNC_END(__memcpy_small)
_ASM_NOKPROBE(__memcpy_small)

/*
 * void *__memcpy_fast(void *dst, const void *src, size_t n)
 *
 * a0: dst
 * a1: src
 * a2: n
 */
SYM_FUNC_START(__memcpy_fast)
        sltui   t0, a2, 9
        bnez    t0, __memcpy_small

        add.d   a3, a1, a2
        add.d   a2, a0, a2
        ld.d    a6, a1, 0
        ld.d    a7, a3, -8

        /* align up destination address */
        andi    t1, a0, 7
        sub.d   t0, zero, t1
        addi.d  t0, t0, 8
        add.d   a1, a1, t0
        add.d   a5, a0, t0

        addi.d  a4, a3, -64
        bgeu    a1, a4, .Llt64

        /* copy 64 bytes at a time */
.Lloop64:
        ld.d    t0, a1, 0
        ld.d    t1, a1, 8
        ld.d    t2, a1, 16
        ld.d    t3, a1, 24
        ld.d    t4, a1, 32
        ld.d    t5, a1, 40
        ld.d    t6, a1, 48
        ld.d    t7, a1, 56
        addi.d  a1, a1, 64
        st.d    t0, a5, 0
        st.d    t1, a5, 8
        st.d    t2, a5, 16
        st.d    t3, a5, 24
        st.d    t4, a5, 32
        st.d    t5, a5, 40
        st.d    t6, a5, 48
        st.d    t7, a5, 56
        addi.d  a5, a5, 64
        bltu    a1, a4, .Lloop64

        /* copy the remaining bytes */
.Llt64:
        addi.d  a4, a3, -32
        bgeu    a1, a4, .Llt32
        ld.d    t0, a1, 0
        ld.d    t1, a1, 8
        ld.d    t2, a1, 16
        ld.d    t3, a1, 24
        addi.d  a1, a1, 32
        st.d    t0, a5, 0
        st.d    t1, a5, 8
        st.d    t2, a5, 16
        st.d    t3, a5, 24
        addi.d  a5, a5, 32

.Llt32:
        addi.d  a4, a3, -16
        bgeu    a1, a4, .Llt16
        ld.d    t0, a1, 0
        ld.d    t1, a1, 8
        addi.d  a1, a1, 16
        st.d    t0, a5, 0
        st.d    t1, a5, 8
        addi.d  a5, a5, 16

.Llt16:
        addi.d  a4, a3, -8
        bgeu    a1, a4, .Llt8
        ld.d    t0, a1, 0
        st.d    t0, a5, 0

.Llt8:
        st.d    a6, a0, 0
        st.d    a7, a2, -8

        /* return */
        jr      ra
SYM_FUNC_END(__memcpy_fast)
_ASM_NOKPROBE(__memcpy_fast)

STACK_FRAME_NON_STANDARD __memcpy_small