usbspeakerlib.c

IXP425的BSP代码

	    pIfDescr->interfaceSubClass == USB_SUBCLASS_AUDIO_AUDIOSTREAMING)
	    {
	    /* We found an AudioStreaming interface descriptor.  Now, determine 
	     * how many bytes until the next interface descriptor.	This 
	     * determines the range of the configuration descriptor we will 
	     * examine while parsing this interface.
	     */

	    pTmp = pCfgBfr;
	    tmpLen = cfgLen;

	    if (usbDescrParseSkip (&pTmp, 
				   &tmpLen, 
				   USB_DESCR_INTERFACE) 
				 != NULL)
		rangeLen = cfgLen - tmpLen;
	    else
		rangeLen = cfgLen;

	    parseInterface (pSeqDev, pIfDescr, pCfgBfr, rangeLen);
	    }
	}


    return OK;
    }


/***************************************************************************
*
* selectFormat - selects an audio format to match the caller's request
*
* <pReqFmt> points to a USB_SPEAKER_AUDIO_FORMAT structure in which the
* "formatTag" field has been initialized to the desired format as
* USB_AUDIO_TYPEn_xxxx and "formatType" has been initialized with the 
* format type as USB_AUDIO_FORMAT_TYPEn.  
*
* Depending on the specified format, the fields "channels", "subFrameSize", 
* "bitRes", "sampleFrequency", "maxBitRate", and "samplesPerFrame" may also 
* need to be specified to qualify the format.  The other fields of the 
* structure *do not* need to be specified.
*
* The field "sampleFrequency", which must be set for Type I & Type 3 formats
* must be set with the desired playback frequency.  The frequency is 
* expressed as samples per sec.  For example, a sampleFrequency of 88,500 
* is 88,500 samples per second per channel.
*
* This function will attempt to find an audio format supported by the
* speaker which is an exact match for the specified format.  If found, that
* format will be selected.  If no exact match can be found, an error will be
* returned.
*
* RETURNS: OK if successful, else ERROR.
*/

LOCAL STATUS selectFormat
    (
    pUSB_SPKR_SEQ_DEV pSeqDev,
    pUSB_SPKR_AUDIO_FORMAT pReqFmt
    )

    {
    pUSB_SPKR_AUDIO_FORMAT pFmt;
    UINT16 i;

    /* Set the format type to "unspecified". */

    pSeqDev->pSelFmt = NULL;

    pSeqDev->sampleFrequency = 0;
    pSeqDev->sampleSize = 0;


    /* Look for an exact match for the format */

    for (i = 0; i < pSeqDev->fmtCount; i++)
	{
	pFmt = &pSeqDev->pFmt [i];

	switch (pReqFmt->formatType)
	    {
	    case USB_AUDIO_FORMAT_TYPE1:
	    case USB_AUDIO_FORMAT_TYPE3:

		if (pReqFmt->formatTag == pFmt->formatTag &&
		    pReqFmt->channels == pFmt->channels &&
		    pReqFmt->subFrameSize == pFmt->subFrameSize &&
		    pReqFmt->bitRes == pFmt->bitRes)

		    {
		    pSeqDev->pSelFmt = pFmt;
		    pSeqDev->sampleFrequency = pReqFmt->sampleFrequency;
		    pSeqDev->sampleSize = pFmt->channels * pFmt->subFrameSize;
		    pSeqDev->bytesPerSec = 
		    pSeqDev->sampleFrequency * pSeqDev->sampleSize;
		    return OK;
		    }
		break;

	    case USB_AUDIO_FORMAT_TYPE2:

	    if (pReqFmt->formatTag == pFmt->formatTag &&
		pReqFmt->maxBitRate == pFmt->maxBitRate &&
		pReqFmt->samplesPerFrame == pFmt->samplesPerFrame)

		{
		pSeqDev->pSelFmt = pFmt;
		pSeqDev->sampleFrequency = pReqFmt->sampleFrequency;
		pSeqDev->sampleSize = 1;
		pSeqDev->bytesPerSec = 
		pSeqDev->sampleFrequency * pSeqDev->sampleSize;
		return OK;
		}
	    break;

	    default:    /* not supported */

	    return ERROR;
	    }
	}


    /* No compatible format was found. */

    return ERROR;
    }


/***************************************************************************
*
* parseAudioConfig - parse configuration descriptor for audio device
*
* Examine the configuration descriptor and build a map of the device's
* capabilities.  To be used by this speaker class driver, the device must
* have an "Output Terminal".  If it does, then determine which audio
* formats can be passed to the device.
*
* RETURNS: OK if successful, else ERROR
*/

LOCAL STATUS parseAudioConfig
    (
    pUSB_SPKR_SEQ_DEV pSeqDev,
    pUINT8 pCfgBfr,
    UINT16 cfgLen,
    pUSB_CONFIG_DESCR pCfgDescr
    )

    {
    /* Find the Audio Control descriptor and build a map of the device */

    if (buildAudioMap (pSeqDev, pCfgBfr, cfgLen) != OK)
	return ERROR;

    if (pSeqDev->outputTerminalId == 0 || pSeqDev->inputTerminalId == 0)
	return ERROR;


    /* The audio device has the necessary Output Terminal.  Parse the
     * configuration descriptor and make a list of the supported audio
     * formats.
     */

    if (buildFormatList (pSeqDev, pCfgBfr, cfgLen) != OK)
	return ERROR;

    if (pSeqDev->fmtCount == 0)
	return ERROR;

    return OK;
    }


/***************************************************************************
*
* configureSeqDev - configure USB speaker for operation
*
* Examine the device's configuration & associated descriptors to determine
* the audio device's capability.  If the device is an audio device capable
* of output (e.g., it includes an "Output Terminal") then build a structure
* to describe the device and configure it.
*
* RETURNS: OK if successful, else ERROR if failed to configure channel
*/

LOCAL STATUS configureSeqDev
    (
    pUSB_SPKR_SEQ_DEV pSeqDev
    )

    {
    pUSB_CONFIG_DESCR pCfgDescr;
    pUINT8 pCfgBfr;
    UINT16 cfgLen;
    STATUS retcode;


    /* Read the configuration descriptor so we can determine the device's
     * capabilities.
     */

    if (usbConfigDescrGet (usbdHandle, 
			   pSeqDev->nodeId, 
			   pSeqDev->configuration, 
			   &cfgLen, 
			   &pCfgBfr) 
			 != OK)
	return ERROR;

    if ((pCfgDescr = usbDescrParse (pCfgBfr, 
				    cfgLen, 
				    USB_DESCR_CONFIGURATION)) 
				  == NULL)
	{
	retcode = ERROR;
	}
    else
	{
	/* Parse the configuration descriptor to see if the device has the
	 * capabilities we need to use it as a speaker.
	 */

	retcode = parseAudioConfig (pSeqDev, pCfgBfr, cfgLen, pCfgDescr);
	}


    if (retcode == OK)
	{
	/* Select the configuration. */

	if (usbdConfigurationSet (usbdHandle, 
				  pSeqDev->nodeId,
				  pCfgDescr->configurationValue, 
				  pCfgDescr->maxPower * USB_POWER_MA_PER_UNIT) 
				!= OK)
	    {
	    retcode = ERROR;
	    }
	}


    /* Release the buffer allocated by usbConfigDescrGet(). */

    OSS_FREE (pCfgBfr);

    return retcode;
    }


/***************************************************************************
*
* destroyAudioStream - releases audio stream, bandwidth, resources
*
* Releases the resources allocated for an audio stream as long as play
* has completed.  If <unconditional> is TRUE, then the stream is 
* destroyed whether or not play has completed. 
*
* RETURNS: N/A
*/

LOCAL VOID destroyAudioStream
    (
    pUSB_SPKR_SEQ_DEV pSeqDev,
    BOOL unconditional
    )

    {
    /* If still playing, return. */

    if (unconditional 
	|| pSeqDev->streamFault 
	|| (!pSeqDev->open && pSeqDev->audioBfrCount == 0))
	{
	/* Destroy the isoch. pipe. */

	if (pSeqDev->isochPipeHandle != NULL)
	    {
	    usbdPipeDestroy (usbdHandle, pSeqDev->isochPipeHandle);
	    pSeqDev->isochPipeHandle = NULL;
	    }

	/* Release buffer-not-full semaphore */

	if (pSeqDev->bfrNotFullSem != NULL)
	    {
	    OSS_SEM_DESTROY (pSeqDev->bfrNotFullSem);
	    pSeqDev->bfrNotFullSem = NULL;
	    }

	/* Release the audio data buffer */

	if (pSeqDev->pAudioBfr != NULL)
	    {
	    OSS_FREE (pSeqDev->pAudioBfr);
	    pSeqDev->pAudioBfr = NULL;
	    }
	}
    }


/***************************************************************************
*
* openAudioStream - Sets up speaker to begin receiving audio data
*
* RETURNS: OK if successful, else EIO if error.
*/

LOCAL STATUS openAudioStream
    (
    pUSB_SPKR_SEQ_DEV pSeqDev
    )

    {
    pUSB_SPKR_AUDIO_FORMAT pFmt = pSeqDev->pSelFmt;
    UINT32 halfBfrLen;


    /* If the audio stream is already open or data is still in the bfr,
     * return an error.
     */

    if (pSeqDev->open || pSeqDev->audioBfrCount > 0)
	return EIO;

    /* Return an error if no audio format specified. */

    if (pFmt == NULL)
	return EIO;


    /* Select the audio interface/alt setting for the indicated format */

    if (usbdInterfaceSet (usbdHandle, 
			  pSeqDev->nodeId,
			  pFmt->interface, 
			  pFmt->altSetting)
			!= OK)
	return EIO;


    /* Calculate the size of the data buffer for the audio stream.  We 
     * calculate the buffer size to ensure one second of buffering capability
     * and to ensure that each half of the buffer accomodates an exactly
     * multiple of the sample size.
     */

    halfBfrLen = pSeqDev->bytesPerSec / 2;
    halfBfrLen = ((halfBfrLen + pSeqDev->sampleSize - 1) / pSeqDev->sampleSize)
			* pSeqDev->sampleSize;


    /* Allocate resources for the stream. */

    pSeqDev->streamFault = FALSE;

    if ((pSeqDev->pAudioBfr = OSS_MALLOC (halfBfrLen * 2)) == NULL)
	return EIO;

    pSeqDev->audioBfrLen = halfBfrLen * 2;
    pSeqDev->audioBfrHalf = halfBfrLen;
    pSeqDev->audioBfrCount = 0;
    pSeqDev->audioBfrIn = 0;
    pSeqDev->audioBfrOut = 0;
    pSeqDev->audioBfrPending = 0;
    pSeqDev->audioBfrTotal = 0;

    pSeqDev->foregroundWaiting = FALSE;

    if (OSS_SEM_CREATE (1, 0, &pSeqDev->bfrNotFullSem) != OK)
	{
	destroyAudioStream (pSeqDev, TRUE);
	return EIO;
	}

    pSeqDev->nextStartFrame = 0;
    pSeqDev->blocksSent = 0;

    pSeqDev->nextIrp = 0;
    pSeqDev->nextDoneIrp = 0;
    pSeqDev->irpsInUse = 0;


    /* Create the isochronous transmit pipe for the audio data. */

    if (usbdPipeCreate (usbdHandle, 
			pSeqDev->nodeId, 
			pFmt->endpoint,
			pSeqDev->configuration, 
			pFmt->interface, 
			USB_XFRTYPE_ISOCH,
			USB_DIR_OUT, 
			pFmt->maxPacketSize, 
			pSeqDev->bytesPerSec, 
			1, 
			&pSeqDev->isochPipeHandle) 
		      != OK)
	{
	destroyAudioStream (pSeqDev, TRUE);
	return EIO;
	}


    pSeqDev->open = TRUE;

    return OK;
    }


/***************************************************************************
*
* closeAudioStream - Marks end of audio stream.
*
* RETURNS: OK if successful, else EIO if error.
*/

LOCAL STATUS closeAudioStream
    (
    pUSB_SPKR_SEQ_DEV pSeqDev
    )

    {
    /* If we're not playing, return an error. */

    if (!pSeqDev->open)
	return EIO;


    /* tear down the isoch pipe, etc., if the audio transmission is 
     * complete...if still transmitting, the stream will be torn down
     * upon completion of the data transfer.
     */

    pSeqDev->open = FALSE;

    destroyAudioStream (pSeqDev, FALSE);

    return OK;
    }


/***************************************************************************
*
* updateTransmitter - starts/restarts double-buffered I/O
*
* NOTE: Caller must ensure speakerMutex is taken before calling this
* routine.
*
* RETURNS: OK if successful, else ERROR.
*/

LOCAL STATUS updateTransmitter
    (
    pUSB_SPKR_SEQ_DEV pSeqDev
    )

    {
    pUSB_IRP pIrp;
    UINT32 currentFrame;
    UINT32 extLen;
    UINT32 frameCount;
    STATUS status = OK;


    /* If an IRP is available and there is data available but not yet
     * being transmitted, then send it.
     */

    while (!pSeqDev->streamFault 
	    && pSeqDev->irpsInUse < IRP_COUNT 
	    && ((pSeqDev->audioBfrCount - pSeqDev->audioBfrPending 
	         >= pSeqDev->audioBfrHalf) 
	    || !pSeqDev->open))
	{
	/* If this is the first block of data, initialize the starting
	 * frame number.
	 */

	if (pSeqDev->blocksSent == 0)
	    {
	    if (usbdCurrentFrameGet (usbdHandle, 
				     pSeqDev->nodeId,
				     &currentFrame, 
				     &pSeqDev->frameWindow) 
				   != OK)
		currentFrame = 0;

	    pSeqDev->nextStartFrame = (currentFrame + FRAME_SKIP) %
	    pSeqDev->frameWindow;
	    }


	/* Use the next IRP to transmit a block of data.  Each IRP always
	 * transfers half of the data buffer or the entire block of 
	 * remaining data if the stream has been closed.
	 */

	extLen = pSeqDev->audioBfrCount - pSeqDev->audioBfrPending;
	extLen = min (extLen, pSeqDev->audioBfrHalf);

	if (extLen < pSeqDev->audioBfrHalf && pSeqDev->open)
	    break;

	frameCount = ((extLen * MSEC_PER_SEC) + pSeqDev->bytesPerSec - 1) / 
	    pSeqDev->bytesPerSec;

	if (frameCount == 0)
	    break;


	/* Initialize the IRP. */

	pIrp = &pSeqDev->irp [pSeqDev->nextIrp];

	pSeqDev->irpsInUse++;

	if (++pSeqDev->nextIrp == IRP_COUNT)
	    pSeqDev->nextIrp = 0;

	memset (pIrp, 0, sizeof (*pIrp));
	
	pIrp->userPtr = pSeqDev;
	pIrp->irpLen = sizeof (*pIrp);
	pIrp->userCallback = usbSpkrIrpCallback;
	pIrp->timeout = USB_TIMEOUT_NONE;
	pIrp->startFrame = pSeqDev->nextStartFrame;
	pIrp->dataBlockSize = pSeqDev->sampleSize;

	pIrp->transferLen = extLen;
	pIrp->bfrCount = 1;
	pIrp->bfrList [0].pid = USB_PID_OUT;
	pIrp->bfrList [0].pBfr = &pSeqDev->pAudioBfr [pSeqDev->audioBfrOut];
	pIrp->bfrList [0].bfrLen = extLen;