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 "SharedRingBuffer"
18 //#define LOG_NDEBUG 0
19 #include <utils/Log.h>
20
21 #include <sys/mman.h>
22
23 #include "binding/RingBufferParcelable.h"
24 #include "binding/AudioEndpointParcelable.h"
25
26 #include "SharedRingBuffer.h"
27
28 using namespace android;
29 using namespace aaudio;
30
~SharedRingBuffer()31 SharedRingBuffer::~SharedRingBuffer()
32 {
33 if (mSharedMemory != nullptr) {
34 delete mFifoBuffer;
35 munmap(mSharedMemory, mSharedMemorySizeInBytes);
36 mSharedMemory = nullptr;
37 }
38 }
39
allocate(fifo_frames_t bytesPerFrame,fifo_frames_t capacityInFrames)40 aaudio_result_t SharedRingBuffer::allocate(fifo_frames_t bytesPerFrame,
41 fifo_frames_t capacityInFrames) {
42 mCapacityInFrames = capacityInFrames;
43
44 // Create shared memory large enough to hold the data and the read and write counters.
45 mDataMemorySizeInBytes = bytesPerFrame * capacityInFrames;
46 mSharedMemorySizeInBytes = mDataMemorySizeInBytes + (2 * (sizeof(fifo_counter_t)));
47 mFileDescriptor.reset(ashmem_create_region("AAudioSharedRingBuffer", mSharedMemorySizeInBytes));
48 if (mFileDescriptor.get() == -1) {
49 ALOGE("allocate() ashmem_create_region() failed %d", errno);
50 return AAUDIO_ERROR_INTERNAL;
51 }
52 ALOGV("allocate() mFileDescriptor = %d\n", mFileDescriptor.get());
53
54 int err = ashmem_set_prot_region(mFileDescriptor.get(), PROT_READ|PROT_WRITE); // TODO error handling?
55 if (err < 0) {
56 ALOGE("allocate() ashmem_set_prot_region() failed %d", errno);
57 mFileDescriptor.reset();
58 return AAUDIO_ERROR_INTERNAL; // TODO convert errno to a better AAUDIO_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.get(), 0);
66 if (mSharedMemory == MAP_FAILED) {
67 ALOGE("allocate() mmap() failed %d", errno);
68 mFileDescriptor.reset();
69 return AAUDIO_ERROR_INTERNAL; // TODO convert errno to a better AAUDIO_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 FifoBuffer(bytesPerFrame, capacityInFrames,
80 readCounterAddress, writeCounterAddress, dataAddress);
81 return AAUDIO_OK;
82 }
83
fillParcelable(AudioEndpointParcelable & endpointParcelable,RingBufferParcelable & ringBufferParcelable)84 void 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