/*
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* Copyright (C) 2016 The Android Open Source Project
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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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#include <errno.h>
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#include <limits.h>
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#include <audio_utils/fifo_index.h>
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#include <audio_utils/futex.h>
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// These are not implemented within <audio_utils/fifo_index.h>
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// so that we don't expose futex.
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uint32_t audio_utils_fifo_index::loadAcquire()
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{
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return atomic_load_explicit(&mIndex, std::memory_order_acquire);
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}
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// FIXME should inline this, so that writer32 can also inline it
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void audio_utils_fifo_index::storeRelease(uint32_t value)
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{
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atomic_store_explicit(&mIndex, value, std::memory_order_release);
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}
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int audio_utils_fifo_index::wait(int op, uint32_t expected, const struct timespec *timeout)
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{
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return sys_futex(&mIndex, op, expected, timeout, NULL, 0);
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}
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int audio_utils_fifo_index::wake(int op, int waiters)
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{
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return sys_futex(&mIndex, op, waiters, NULL, NULL, 0);
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}
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uint32_t audio_utils_fifo_index::loadConsume()
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{
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return atomic_load_explicit(&mIndex, std::memory_order_consume);
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}
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////
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RefIndexDeferredStoreReleaseDeferredWake::RefIndexDeferredStoreReleaseDeferredWake(
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audio_utils_fifo_index& index)
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: mIndex(index), mValue(0), mWriteback(false), mWaiters(0), mWakeOp(FUTEX_WAIT_PRIVATE)
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{
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}
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RefIndexDeferredStoreReleaseDeferredWake::~RefIndexDeferredStoreReleaseDeferredWake()
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{
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writeback();
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wakeNowIfNeeded();
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}
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void RefIndexDeferredStoreReleaseDeferredWake::set(uint32_t value) {
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mValue = value;
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mWriteback = true;
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}
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void RefIndexDeferredStoreReleaseDeferredWake::writeback()
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{
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if (mWriteback) {
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// TODO When part of a collection, should use relaxed for all but the last writeback
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mIndex.storeRelease(mValue);
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mWriteback = false;
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}
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}
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void RefIndexDeferredStoreReleaseDeferredWake::writethrough(uint32_t value) {
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set(value);
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writeback();
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}
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void RefIndexDeferredStoreReleaseDeferredWake::wakeDeferred(int op, int waiters)
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{
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if (waiters <= 0) {
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return;
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}
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// default is FUTEX_WAKE_PRIVATE
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if (op == FUTEX_WAKE) {
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mWakeOp = FUTEX_WAKE;
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}
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if (waiters < INT_MAX - mWaiters) {
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mWaiters += waiters;
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} else {
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mWaiters = INT_MAX;
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}
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}
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void RefIndexDeferredStoreReleaseDeferredWake::wakeNowIfNeeded()
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{
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if (mWaiters > 0) {
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mIndex.wake(mWakeOp, mWaiters);
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mWaiters = 0;
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mWakeOp = FUTEX_WAKE_PRIVATE;
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}
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}
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void RefIndexDeferredStoreReleaseDeferredWake::wakeNow(int op, int waiters)
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{
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wakeDeferred(op, waiters);
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wakeNowIfNeeded();
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}
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////
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RefIndexCachedLoadAcquireDeferredWait::RefIndexCachedLoadAcquireDeferredWait(
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audio_utils_fifo_index& index)
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: mIndex(index), mValue(0), mLoaded(false)
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{
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}
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RefIndexCachedLoadAcquireDeferredWait::~RefIndexCachedLoadAcquireDeferredWait()
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{
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}
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uint32_t RefIndexCachedLoadAcquireDeferredWait::get()
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{
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prefetch();
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return mValue;
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}
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void RefIndexCachedLoadAcquireDeferredWait::prefetch()
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{
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if (!mLoaded) {
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// TODO When part of a collection, should use relaxed for all but the last load
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mValue = mIndex.loadAcquire();
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mLoaded = true;
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}
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}
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void RefIndexCachedLoadAcquireDeferredWait::invalidate()
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{
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mLoaded = false;
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}
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#if 0
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uint32_t RefIndexCachedLoadAcquireDeferredWait::readthrough()
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{
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invalidate();
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return get();
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}
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#endif
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int RefIndexCachedLoadAcquireDeferredWait::wait(int op, const struct timespec *timeout)
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{
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if (!mLoaded) {
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return -EINVAL;
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}
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int err = mIndex.wait(op, mValue /*expected*/, timeout);
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invalidate();
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return err;
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}
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