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Using DSP/BIOS EDMA McBSP driver on OMAP3530?

Other Parts Discussed in Thread: OMAP3530, DM3730, SYSBIOS

We want to use the OMAP3530 in a product that analyses audio data. The bandwidth of analysed data is very low compared to original audio bandwidth. I have some concern about the linux kernel not being real time, so I would like to read the audio data from an DSP application.

So, basically I want to port the driver decribed in "spra846" to OMAP3530

Before I start doing work on that, I would like to find out if this approach can work at all.

I have already read the following posts:

  • https://e2e.ti.com/support/dsp/omap_applications_processors/f/447/t/30250.aspx
  • https://e2e.ti.com/support/embedded/f/355/p/58905/210095.aspx

I think I would need to do the following:

  • leave the McBSP untouched by the linux kernel
  • do the CSL for the DSP

Things I don't know:

  • is the EDMA used from Linux (it seems it is DSP only)?
  • can the EDMA access the McBSP?
  • are there any performance issues with this approach?

Thanks in advance

  Jan-Hinnerk Dumjahn

  • Hi Jan-Hinnerk,

     

    I'm fighting with a similar problem at the moment and I was wondering if you (or anyone else who may come across this) has had any joy with this?

     

    For those reading we're working on an audio system with Audio->DSP/Bios Codec -> ARM/Linux (transport) and the basic architecture.  At the moment I have the mcbsps working, though I'm strugging with the DMA side of things.

     

    All help and insight, gratefully received.

     

    paddy

  • Hi Patrick,

    we postponed the implementation.

    For now we are using ALSA drivers (which use DMA) to fetch the audio data and pass the data to DSP via CodecEngine. This works well enough for us because our only concern is about loosing data, not data being delayed.

    Haven't seen any data loss yet.

    Cheers

      Jan-Hinnerk

  • Hi Jan-Hinnerk 

     

    I have spent about 3 weeks searching for a way to acquire the signal directly to the DSP , Actually i use DM3730 over the BeagleBoard, But I have got no results till now , so i have changed my mind and trying to use ALSA drivers 

    So could you please Show me the steps to have ALSA drivers over my Beagle .... i'm Using Angstrom , kernel 2.6.32

     

    Thanks in Advance 

  • Hi,   Jan-Hinnerk Dumjahn

    That means, you want to develop the stand alone code that will decode the audio file and will play it through audio out independent of os used.

    Note that there is no CSL available for the OMAP3530's C64x+ part my friend. Ya, there are application avilable that will use linux OS driver itself can make your work easier like DSPLink, COdec Engine stuff.

    But, if you want to work independently of the linux and Other OS environment then, you need to have mp3 decoder to decode , McBSp Rx/Tx code, some part of loopback example etc.Even i am working on the same thing and i had successfully debugged mp3decoder and McBSP Rx/Tx code independently,and corrently working to combine them all.

    Is that kind of project you want then let me know about it.

    Note: I think you will get idea about the Soc from below link and please note that still there are no PSP releases available for OMAP 35350 for MCBSP and other peripheral using SYSBIOS. Either we can go for DSP/BIOS and write the appropriate driver for it.

    http://processors.wiki.ti.com/index.php/Audio_Soc_example

     

    With Regards

    Nitin Mewada