audiobuffer.c

本程序为ST公司开发的源代码

#endif                                    
				  DMA_MAX0 = AudioDataLength*4;		      
			      if(!pause_active)
			      { //pause not requested, start DMA
				    AB_current_position = AudioBuffer[g_AudioBufferReadFrom].Position;
				    AB_current_bitrate = AudioBuffer[g_AudioBufferReadFrom].Bitrate;
				    enable_DMA0();
				  }
			      else
				  { //pause requested, don't start DMA
				    mute_on();
				    pause_active = 2;
                    if(!CIF_CONF.field.src)  
            {
              // Not Compressed Audio - repeat last transfer to activate mute
              DMA_SOURCE_HI0 = ((uint32)(AudioBuffer[g_AudioBufferReadFrom_Prev].data) >> 16);   //[MM] 11/08/2006
              DMA_SOURCE_LO0 = ((uint32)(AudioBuffer[g_AudioBufferReadFrom_Prev].data) & 0xFFFF);//[MM] 11/08/2006
              //DMA_MAX0 should not be re-initialized it has the value of the last Transfer
              enable_DMA0(); //[MM] 11/08/2006
              Activate_Mute = 1; //[MM] 11/08/06
              g_ABempty--;
              AudioBuffer[g_AudioBufferReadFrom_Prev].status = abDataReady;
            }
				    
				  }
		      }
			  else
			  {
			    mute_on();
                if(!CIF_CONF.field.src) 
                {
                  // Not Compressed Audio - repeat last transfer to activate mute
                  DMA_SOURCE_HI0 = ((uint32)(AudioBuffer[g_AudioBufferReadFrom_Prev].data) >> 16);   //[MM] 11/08/2006
                  DMA_SOURCE_LO0 = ((uint32)(AudioBuffer[g_AudioBufferReadFrom_Prev].data) & 0xFFFF);//[MM] 11/08/2006
                  //DMA_MAX0 should not be re-initialized it has the value of the last Transfer
                  enable_DMA0(); //[MM] 11/08/2006
                  Activate_Mute = 1; //[MM] 11/08/06
                  g_ABempty--;
                  AudioBuffer[g_AudioBufferReadFrom_Prev].status = abDataReady;
                }
                else
                {
                  // Compressed Audio
                  DMAunderflow = 1;
                  src_stop();	
                }
		      } 
	   }	      
     } 

     if(dma_status.field.err0)
     {
      DMA_CLR.field.sec0 = 1;
     }
    
    
    //EIC_FIR.field.dma0_fiq_ip = 1;
}
 
void dma_ch0_isr_irq(void)
{
	event_set_dma0_xfer(READY);
	event_disable_scheduling();
    event_out_shedule(DMA0_IRQ_XFER_EVENT);
    event_out_shedule(DECODER_TIME_EVENT);  // copy to event_pending & wake
    event_enable_scheduling();		
}
 

void ReconfigureDMA_CH0(t_fileType FileType)
{
		CIF_CONF.field.wr_en = 0;
		
		switch(FileType)
		{
		case ft_Audio:
		  //uncompressed audio
  		  SetDMAChannel(DMA_CH0,CHITF_WR_CH);
  		  SetUpDMA(DMA_CH0,
                (uint32 *) NULL,              // Source Address
                (uint32 *) &CIF_WRDATA,                // Destination Address
                DMA_WORD_SIZE_IS_BYTE,         // Source Word Size 
                DMA_WORD_SIZE_IS_WORD,         // Destination Word Size
                0,                                 // Number of Words
                DMA_BURST_IS_8_WORD,                // Burst Size
                DMA_INCREMENT ,                     // Source Inc
                DMA_NO_INCREMENT ,                  // Peripheral Inc
                DMA_PERIPHERAL_IS_THE_DESTINATION,  // Peripheral is Destination
                0);                                 // Mem 2 Mem Enable
		  
		  break;
		default:
		  //compressed audio
		  SetDMAChannel(DMA_CH0, SRC_DRE_CH);
  		  SetUpDMA(DMA_CH0,
                (uint32 *) NULL,              // Source Address
                (uint32 *) &SRC_DIF,                // Destination Address
                DMA_WORD_SIZE_IS_HALF_WORD,         // Source Word Size 
                DMA_WORD_SIZE_IS_HALF_WORD,         // Destination Word Size
                0,                                 // Number of Words
                DMA_BURST_IS_4_WORD,                // Burst Size
                DMA_INCREMENT ,                     // Source Inc
                DMA_NO_INCREMENT ,                  // Peripheral Inc
                DMA_PERIPHERAL_IS_THE_DESTINATION,  // Peripheral is Destination
                0);                                 // Mem 2 Mem Enable
		  
		  break;
		}
}

void AudioBufferResetPosition(void)  /* BB060926a */
{
  //wait till DMA xfer is finished
  
  //while(DMA_CTRL0.field.enable);
  while(dma_ch0_fiq);

  memset((void*)(&AB_lastplay_position),0,sizeof(t_position));
  memset((void*)(&AB_current_position),0,sizeof(t_position));
  AB_lastplay_bitrate = 0;
  AB_current_bitrate = 0;
}



void AudioBufferInit(void)
{
	uint8 i;
	g_AudioBufferWriteTo = 0;
	g_AudioBufferReadFrom = 0;
	g_ABempty = AudioBufferElements;
	
	for (i = 0; i < AudioBufferElements ; i++)
	{
		AudioBuffer[i].status = abEmpty;
	}
	
	AudioBufferResetPosition();  /* BB060926a */	
	
	// *** INIT SRC *** //
	CurrentSampleRateConverterFrequency = kDecoderSampleRate_Undefined;	
	src_init();
	oif_init(); //[OK] - enable DAC and buffered path
	
	DMAunderflow = 1;
	
}

pAudioBufferData AudioBufferHaveSpace(eDecoderSampleRate SampleRate)
{
	pAudioBufferData ret = NULL;
	
	DISABLE_INTERRUPTS();

    if (SampleRate != CurrentSampleRateConverterFrequency)
	{
	  // request that all AB elements are empty, to reconfigure SRC
		if (g_ABempty < AudioBufferElements)
		{
			goto exitf;
		}
		
		g_ABempty = AudioBufferElements;
		
		CurrentSampleRateConverterFrequency = SampleRate;
		
		// reconfigure SRC
		SRCSetFrequency(CurrentSampleRateConverterFrequency);	
	}

	
	if (AudioBuffer[g_AudioBufferWriteTo].status == abEmpty)
	{		
		ret = (AudioBuffer[g_AudioBufferWriteTo].data);
	}
	
 exitf:
	ENABLE_INTERRUPTS();
	
	return ret;
}

void AudioBufferSetFull(uint32 num_samples, ElementFlagType ElementFlag, tDecoderTime_event *TimeEvent, t_position *Position)
{
	
	AudioBuffer[g_AudioBufferWriteTo].ElementFlag = ElementFlag;
	AudioBuffer[g_AudioBufferWriteTo].status = abDataReady;
	AudioBuffer[g_AudioBufferWriteTo].DataLength = num_samples;
	AudioBuffer[g_AudioBufferWriteTo].TimeEvent = *TimeEvent;
	AudioBuffer[g_AudioBufferWriteTo].Position = *Position;
	AudioBuffer[g_AudioBufferWriteTo].Bitrate = GetCurrentBitRate();


	DISABLE_INTERRUPTS();
    g_ABempty--; // decrement number of empty AB elements
	
	if(DMAunderflow)
	{ //DMA is stopped
#if (DEBUG_INCLUDE_COUNTERS==1)
	    extern uint32 countABUnderflows; // [RB] debug
	    countABUnderflows++; // [RB] debug
#endif
		DMAunderflow = 0;
		src_restart_done = 0;
		// start DMA
		set_DMA0((uint32*)(AudioBuffer[g_AudioBufferWriteTo].data),num_samples *4);		
		event_disable_scheduling();
		if(!pause_active)
        { //pause not requested, start DMA
#if (1 == HAVE_SHOCK_MEMORY)
          if((CurrentFileType == ft_Audio) && (ADPCM_ON == cap_config.adpcm))
          {
            OIF_SOFT_RST.field.adpcm_dec_rst = 1;          
          }
#endif                                    
          //src_restart is set there if executed.
          //Point 1)
          start_dma0_xfer();

#if (1 == HAVE_SHOCK_MEMORY)
          if(ADPCM_ON == cap_config.adpcm)
          {
            OIF_SOFT_RST.field.adpcm_dec_rst = 0;	
          }                        
#endif                                    
		}
        else
        { //pause requested, don't start DMA
		  pause_active = 2;
		}
		event_enable_scheduling();

		if (CurrentFileType != ft_Audio)
		{ //compressed audio
		  // Don't execute SRC restart if already excuted in point
		  // 1)
		  if(0 == src_restart_done)
		  {
	       src_restart();
	      } 
		}
		else
		{ //CDDA
		  enable_CIF();
		}		
	}	
	ENABLE_INTERRUPTS();
		
    if (AudioBuffer[g_AudioBufferWriteTo].ElementFlag == FT_FIRST)
    {
      AudioBuffer[g_AudioBufferWriteTo].ElementFlag = FT_MIDDLE;
    }
    
	g_AudioBufferWriteTo = (g_AudioBufferWriteTo+1)%AudioBufferElements;	
}



void ResetAudioBuffer(void)
{
	uint8  i;
   
    //At the end of a DMA Xfer the DMA_CTRL0.field.enable is set
    //to 0 before generation of FIQ interrupt.
    //In the previous version, the complete data song Transfer was checked 
    //In the following way:
    //
    //while(DMA_CTRL0.field.enable);
    //
    //But it could happen that the the DMA_CTRL0.field.enable bit is checked to 0
    //and then FIQ starts and the ResetAudioBuffer runs with a running FIQ.
    //This caused unrecoverable noise on Audio Output with CD DA.
    	
	//wait till DMA xfer is finished
	#if 0
	while(1)
	{
	 val1 = DMA_CTRL0.field.enable;
	 for(i = 0; i < 100; i++); 
	 val2 = DMA_CTRL0.field.enable;
	 for(i = 0; i < 100; i++); 
	 val3 = DMA_CTRL0.field.enable;
	 for(i = 0; i < 100; i++); 
		  
	 val = val1 + val2 + val3;
	 if(val == 0)
	 {
	  break;
	 }
	}
	#endif
	while(dma_ch0_fiq);
	//wait till DMA xfer is finished
	
	
	g_AudioBufferWriteTo = 0;
	g_AudioBufferReadFrom = 0;
	g_ABempty = AudioBufferElements;
	
	for (i = 0; i < AudioBufferElements ; i++)
	{
		AudioBuffer[i].status = abEmpty;
		AudioBuffer[i].ElementFlag = FT_MIDDLE;
	}
	
	
	DMAunderflow = 1;


}


pAudioBufferData AudioBufferRead(uint32 *DataLength)
{
	pAudioBufferData ret = NULL;
	if (AudioBuffer[g_AudioBufferReadFrom].status == abDataReady)
	{
		
		ret = (AudioBuffer[g_AudioBufferReadFrom].data);
		*DataLength = AudioBuffer[g_AudioBufferReadFrom].DataLength; // in Bytes
		
	}
	return ret;
}