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511107d85d
This adds an implementation of riscv_get_time() API that is using rdtime instruction. This is the case for S-mode U-Boot, and is useful for processors that support rdtime in M-mode too. Signed-off-by: Anup Patel <anup@brainfault.org> Signed-off-by: Bin Meng <bmeng.cn@gmail.com> Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
39 lines
676 B
C
39 lines
676 B
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2018, Anup Patel <anup@brainfault.org>
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* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
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*
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* The riscv_get_time() API implementation that is using the
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* standard rdtime instruction.
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*/
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#include <common.h>
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/* Implement the API required by RISC-V timer driver */
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int riscv_get_time(u64 *time)
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{
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#ifdef CONFIG_64BIT
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u64 n;
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__asm__ __volatile__ (
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"rdtime %0"
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: "=r" (n));
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*time = n;
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#else
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u32 lo, hi, tmp;
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__asm__ __volatile__ (
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"1:\n"
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"rdtimeh %0\n"
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"rdtime %1\n"
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"rdtimeh %2\n"
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"bne %0, %2, 1b"
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: "=&r" (hi), "=&r" (lo), "=&r" (tmp));
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*time = ((u64)hi << 32) | lo;
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#endif
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return 0;
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}
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