关于音频驱动的数据同步问题？

发布于 2017-11-01 16:33:33 浏览：1982 订阅该版

3 个回答

aozima 2017-11-01

调网络不抓包，调I2C等时序不上逻辑分析仪，就像电工不用万用表！多用整理的好的文字，比截图更省流量，还能在整理过程中思考。

qq_青青 2017-11-01

这家伙很懒，什么也没写！

audio.c ：

```

static   rt_err_t  _audio_send_replay_frame(struct rt_audio_device *audio)
{
    rt_err_t result = RT_EOK;
    rt_base_t level;
    struct rt_audio_frame frame;

RT_ASSERT(audio != RT_NULL);

//check repaly queue is empty
    if (rt_data_queue_peak(&audio->replay->queue, &frame.data_ptr, &frame.data_size) != RT_EOK)
    {
        AUDIO_DBG("TX queue is empty
");
        result = -RT_EEMPTY;

level = rt_hw_interrupt_disable();
        audio->replay->activated = RT_FALSE;
        rt_hw_interrupt_enable(level);

goto _exit;
    }

if (audio->ops->transmit != RT_NULL)
    {
        AUDIO_DBG("audio transmit...
");
        if (audio->ops->transmit(audio, frame.data_ptr, RT_NULL, frame.data_size) != frame.data_size)
        {
            result = -RT_EBUSY;

goto _exit;
        }
    }

//pop the head frame...
    rt_data_queue_pop(&audio->replay->queue, &frame.data_ptr, &frame.data_size,  RT_WAITING_FOREVER);

_exit: return result;
}

static rt_size_t  _audio_dev_write(struct rt_device *dev, rt_off_t pos, const void *buffer, rt_size_t size)
{
    rt_err_t result = RT_EOK;
    rt_base_t level;
    struct rt_audio_device *audio;

RT_ASSERT(dev != RT_NULL);
    audio = (struct rt_audio_device *) dev;

if (!(dev->open_flag & RT_DEVICE_OFLAG_WRONLY) || (audio->replay == RT_NULL))
        return 0;

AUDIO_DBG("audio write : pos = %d,buffer = %x,size = %d
",pos,(rt_uint32_t)buffer,size);
    //push a new frame to tx queue
    {
        result = rt_data_queue_push(&audio->replay->queue, buffer, size,
        RT_WAITING_FOREVER);
        if (result != RT_EOK)
        {
            AUDIO_DBG("TX frame queue push error
");
            rt_set_errno(-RT_EFULL);
            return 0;
        }
    }

//check tx state...
    level = rt_hw_interrupt_disable();
    if (audio->replay->activated != RT_TRUE)
    {
        audio->replay->activated = RT_TRUE;
        rt_hw_interrupt_enable(level);

_audio_send_replay_frame(audio);
    }

return size;
}

void rt_audio_tx_complete(struct rt_audio_device *audio, rt_uint8_t *pbuf)
{
    rt_err_t result;
    AUDIO_DBG("audio tx complete ptr=%x...
",(rt_uint32_t)pbuf);

//try to send all frame
    do
    {
        result = _audio_send_replay_frame(audio);
    } while (result == RT_EOK);

/* notify transmitted complete. */
    if (audio->parent.tx_complete != RT_NULL)
        audio->parent.tx_complete(&audio->parent, (void *) pbuf);
}
```

自己的音频设备驱动：

```

uint16_t  *CplBuf = RT_NULL;

void HAL_I2S_TxCpltCallback ( I2S_HandleTypeDef *hi2s ) //DMA发送完成中断回调函数
{
     rt_audio_tx_complete( &audio1, ( rt_uint8_t * ) CplBuf );
}

static rt_size_t  audio_transmit( struct rt_audio_device *audio, const void* writeBuf, void *readBuf, rt_size_t size )
{
     uint8_t reg_value = 0;
     I2Cx_WriteMultiple ( &I2cHandle, AUDIO_I2C_ADDRESS, 64, (uint8_t*)(®_value), 1 );
     HAL_I2S_Transmit_DMA( &I2sHandle, (uint16_t *writeBuf ), size/2 );

CplBuf = ( uint16_t * )writeBuf;
}

```

我的思路是在DMA的发送完成中断回调函数HAL_I2S_TxCpltCallback() 中调用rt_audio_tx_complete() ，使得每次DMA发送完产生中断就调用tx_complete()释放一个内存块，但是在调试中发现rt_audio_tx_complete()中的do...while...循环要队列为空时才会跳出，继而执行内存块的释放，用串口打印调试信息发现一直在对同一个内存块进行写和释放，我的疑问是：
1、听音频的背景音有很小的哒哒哒声音，是不是就说明运行时音频数据流不连续？
2、能否像这样将rt_audio_tx_complete（）放到DMA中断中调用？
3、如果可以的话rt_audio_tx_complete（）中的do...while()循环如何处理？循环过程中将多个队列pop直至队列为空后，然后释放的是哪一个内存块？