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
28using namespace android;
29using namespace aaudio;
30
31SharedRingBuffer::~SharedRingBuffer()
32{
33    if (mSharedMemory != nullptr) {
34        delete mFifoBuffer;
35        munmap(mSharedMemory, mSharedMemorySizeInBytes);
36        mSharedMemory = nullptr;
37    }
38}
39
40aaudio_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
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