363 lines
8.1 KiB
C
363 lines
8.1 KiB
C
/*
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* Copyright (c) 2016 Intel Corporation
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* Copyright (c) 2011-2014 Wind River Systems, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/**
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* @file Atomic ops for ARC EM
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*
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* This module provides the atomic operators for ARC EM family processors
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* which do not support native atomic operations.
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*
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* The atomic operations are guaranteed to be atomic with respect
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* to interrupt service routines, and to operations performed by peer
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* processors.
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*
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* (originally from x86's atomic.c)
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*/
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#include <atomic.h>
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#include <toolchain.h>
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#include <arch/arc/v2/irq.h>
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/**
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*
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* @brief Atomic compare-and-set primitive
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*
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* This routine provides the compare-and-set operator. If the original value at
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* <target> equals <oldValue>, then <newValue> is stored at <target> and the
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* function returns 1.
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*
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* If the original value at <target> does not equal <oldValue>, then the store
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* is not done and the function returns 0.
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*
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* The reading of the original value at <target>, the comparison,
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* and the write of the new value (if it occurs) all happen atomically with
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* respect to both interrupts and accesses of other processors to <target>.
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*
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* @param target address to be tested
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* @param old_value value to compare against
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* @param new_value value to compare against
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* @return Returns 1 if <new_value> is written, 0 otherwise.
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*/
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FUNC_NO_FP int atomic_cas(atomic_t *target, atomic_val_t old_value,
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atomic_val_t new_value)
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{
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unsigned int key;
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int ret = 0;
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key = irq_lock();
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if (*target == old_value) {
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*target = new_value;
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ret = 1;
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}
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic addition primitive
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*
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* This routine provides the atomic addition operator. The <value> is
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* atomically added to the value at <target>, placing the result at <target>,
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* and the old value from <target> is returned.
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*
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* @param target memory location to add to
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* @param value the value to add
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_add(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target += value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic subtraction primitive
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*
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* This routine provides the atomic subtraction operator. The <value> is
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* atomically subtracted from the value at <target>, placing the result at
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* <target>, and the old value from <target> is returned.
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*
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* @param target the memory location to subtract from
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* @param value the value to subtract
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_sub(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target -= value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic increment primitive
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*
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* @param target memory location to increment
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*
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* This routine provides the atomic increment operator. The value at <target>
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* is atomically incremented by 1, and the old value from <target> is returned.
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*
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* @return The value from <target> before the increment
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*/
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FUNC_NO_FP atomic_val_t atomic_inc(atomic_t *target)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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(*target)++;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic decrement primitive
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*
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* @param target memory location to decrement
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*
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* This routine provides the atomic decrement operator. The value at <target>
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* is atomically decremented by 1, and the old value from <target> is returned.
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*
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* @return The value from <target> prior to the decrement
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*/
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FUNC_NO_FP atomic_val_t atomic_dec(atomic_t *target)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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(*target)--;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic get primitive
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*
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* @param target memory location to read from
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*
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* This routine provides the atomic get primitive to atomically read
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* a value from <target>. It simply does an ordinary load. Note that <target>
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* is expected to be aligned to a 4-byte boundary.
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*
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* @return The value read from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_get(const atomic_t *target)
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{
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return *target;
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}
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/**
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*
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* @brief Atomic get-and-set primitive
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*
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* This routine provides the atomic set operator. The <value> is atomically
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* written at <target> and the previous value at <target> is returned.
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*
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* @param target the memory location to write to
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* @param value the value to write
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_set(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target = value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic clear primitive
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*
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* This routine provides the atomic clear operator. The value of 0 is atomically
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* written at <target> and the previous value at <target> is returned. (Hence,
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* atomic_clear(pAtomicVar) is equivalent to atomic_set(pAtomicVar, 0).)
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*
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* @param target the memory location to write
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_clear(atomic_t *target)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target = 0;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic bitwise inclusive OR primitive
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*
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* This routine provides the atomic bitwise inclusive OR operator. The <value>
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* is atomically bitwise OR'ed with the value at <target>, placing the result
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* at <target>, and the previous value at <target> is returned.
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*
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* @param target the memory location to be modified
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* @param value the value to OR
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_or(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target |= value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic bitwise exclusive OR (XOR) primitive
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*
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* This routine provides the atomic bitwise exclusive OR operator. The <value>
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* is atomically bitwise XOR'ed with the value at <target>, placing the result
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* at <target>, and the previous value at <target> is returned.
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*
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* @param target the memory location to be modified
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* @param value the value to XOR
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_xor(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target ^= value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic bitwise AND primitive
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*
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* This routine provides the atomic bitwise AND operator. The <value> is
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* atomically bitwise AND'ed with the value at <target>, placing the result
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* at <target>, and the previous value at <target> is returned.
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*
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* @param target the memory location to be modified
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* @param value the value to AND
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_and(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target &= value;
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irq_unlock(key);
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return ret;
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}
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/**
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*
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* @brief Atomic bitwise NAND primitive
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*
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* This routine provides the atomic bitwise NAND operator. The <value> is
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* atomically bitwise NAND'ed with the value at <target>, placing the result
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* at <target>, and the previous value at <target> is returned.
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*
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* @param target the memory location to be modified
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* @param value the value to NAND
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*
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* @return The previous value from <target>
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*/
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FUNC_NO_FP atomic_val_t atomic_nand(atomic_t *target, atomic_val_t value)
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{
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unsigned int key;
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atomic_val_t ret;
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key = irq_lock();
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ret = *target;
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*target = ~(*target & value);
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irq_unlock(key);
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return ret;
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}
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