/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Anup Patel <anup.patel@wdc.com>
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*/
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#include <sbi/riscv_barrier.h>
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#include <sbi/riscv_locks.h>
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int spin_lock_check(spinlock_t *lock)
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{
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return (lock->lock == __RISCV_SPIN_UNLOCKED) ? 0 : 1;
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}
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int spin_trylock(spinlock_t *lock)
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{
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int tmp = 1, busy;
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__asm__ __volatile__(
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" amoswap.w %0, %2, %1\n" RISCV_ACQUIRE_BARRIER
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: "=r"(busy), "+A"(lock->lock)
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: "r"(tmp)
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: "memory");
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return !busy;
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}
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void spin_lock(spinlock_t *lock)
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{
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while (1) {
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if (spin_lock_check(lock))
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continue;
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if (spin_trylock(lock))
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break;
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}
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}
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void spin_unlock(spinlock_t *lock)
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{
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__smp_store_release(&lock->lock, __RISCV_SPIN_UNLOCKED);
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}
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