SharedRingBuffer.cpp revision 2355edbcacfcb6e852a8707d893aaca788d42fdc 
1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "OboeService"
18//#define LOG_NDEBUG 0
19#include <utils/Log.h>
20
21#include "AudioClock.h"
22#include "AudioEndpointParcelable.h"
23
24//#include "OboeServiceStreamBase.h"
25//#include "OboeServiceStreamFakeHal.h"
26
27#include "SharedRingBuffer.h"
28
29using namespace android;
30using namespace oboe;
31
32SharedRingBuffer::~SharedRingBuffer()
33{
34    if (mSharedMemory != nullptr) {
35        delete mFifoBuffer;
36        munmap(mSharedMemory, mSharedMemorySizeInBytes);
37        close(mFileDescriptor);
38        mSharedMemory = nullptr;
39    }
40}
41
42oboe_result_t SharedRingBuffer::allocate(fifo_frames_t   bytesPerFrame,
43                                         fifo_frames_t   capacityInFrames) {
44    mCapacityInFrames = capacityInFrames;
45
46    // Create shared memory large enough to hold the data and the read and write counters.
47    mDataMemorySizeInBytes = bytesPerFrame * capacityInFrames;
48    mSharedMemorySizeInBytes = mDataMemorySizeInBytes + (2 * (sizeof(fifo_counter_t)));
49    mFileDescriptor = ashmem_create_region("OboeSharedRingBuffer", mSharedMemorySizeInBytes);
50    if (mFileDescriptor < 0) {
51        ALOGE("SharedRingBuffer::allocate() ashmem_create_region() failed %d", errno);
52        return OBOE_ERROR_INTERNAL;
53    }
54    int err = ashmem_set_prot_region(mFileDescriptor, PROT_READ|PROT_WRITE); // TODO error handling?
55    if (err < 0) {
56        ALOGE("SharedRingBuffer::allocate() ashmem_set_prot_region() failed %d", errno);
57        close(mFileDescriptor);
58        return OBOE_ERROR_INTERNAL; // TODO convert errno to a better OBOE_ERROR;
59    }
60
61    // Map the fd to memory addresses.
62    mSharedMemory = (uint8_t *) mmap(0, mSharedMemorySizeInBytes,
63                         PROT_READ|PROT_WRITE,
64                         MAP_SHARED,
65                         mFileDescriptor, 0);
66    if (mSharedMemory == MAP_FAILED) {
67        ALOGE("SharedRingBuffer::allocate() mmap() failed %d", errno);
68        close(mFileDescriptor);
69        return OBOE_ERROR_INTERNAL; // TODO convert errno to a better OBOE_ERROR;
70    }
71
72    // Get addresses for our counters and data from the shared memory.
73    fifo_counter_t *readCounterAddress =
74            (fifo_counter_t *) &mSharedMemory[SHARED_RINGBUFFER_READ_OFFSET];
75    fifo_counter_t *writeCounterAddress =
76            (fifo_counter_t *) &mSharedMemory[SHARED_RINGBUFFER_WRITE_OFFSET];
77    uint8_t *dataAddress = &mSharedMemory[SHARED_RINGBUFFER_DATA_OFFSET];
78
79    mFifoBuffer = new(std::nothrow) FifoBuffer(bytesPerFrame, capacityInFrames,
80                                 readCounterAddress, writeCounterAddress, dataAddress);
81    return (mFifoBuffer == nullptr) ? OBOE_ERROR_NO_MEMORY : OBOE_OK;
82}
83
84void SharedRingBuffer::fillParcelable(AudioEndpointParcelable &endpointParcelable,
85                    RingBufferParcelable &ringBufferParcelable) {
86    int fdIndex = endpointParcelable.addFileDescriptor(mFileDescriptor, mSharedMemorySizeInBytes);
87    ringBufferParcelable.setupMemory(fdIndex,
88                                     SHARED_RINGBUFFER_DATA_OFFSET,
89                                     mDataMemorySizeInBytes,
90                                     SHARED_RINGBUFFER_READ_OFFSET,
91                                     SHARED_RINGBUFFER_WRITE_OFFSET,
92                                     sizeof(fifo_counter_t));
93    ringBufferParcelable.setBytesPerFrame(mFifoBuffer->getBytesPerFrame());
94    ringBufferParcelable.setFramesPerBurst(1);
95    ringBufferParcelable.setCapacityInFrames(mCapacityInFrames);
96}
97