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