MMU mapping CMEM Buffers

hero _hont

Other Parts Discussed in Thread: OMAP3530

hih pro

I was aware that the DSP of the OMAP3530 has a memory management unit, but so far I never had to deal with it. Dsplink initialized the MMU and enabled access to all the DSP memory and all peripherals I accessed so far. However, this time I passed a pointer to a memory block allocated via CMEM to the DSP. This triggered a page fault. Now what? I did some research and figured out that the CodecEngine enables access to the CMEM memory. I don’t use the CodecEngine, so I have to do it on my own.

thanks...

over 15 years ago

Chris Ring over 15 years ago

TI__Genius 17205 points

There are some details, including code examples, toward the end of this article:

http://processors.wiki.ti.com/index.php/OMAP3_DSP_MMU_Configuration

Note that CMEM has an API - CMEM_getBlockAttrs() - to retrieve the CMEM block attributes at runtime. This can help insulate the application from the CMEM insmod params, enabling the system integrator to shuffle memory around without changing the app.

Chris

Robert Tivy over 15 years ago

TI__Mastermind 18260 points

You need to add an entry to the DSPLink configuration object and pass it to the PROC_setup DSPLink API (or Proc_setup, depending on version of DSPLink). You will need to add a 'memTable[]' entry for CMEM. See here for help: http://processors.wiki.ti.com/index.php/Changing_DSPLink_Memory_Map.

Regards,

- Rob

Deepali Uppal over 15 years ago in reply to Robert Tivy

TI__Expert 4930 points

A couple of link which might provide more info:

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

http://processors.wiki.ti.com/index.php/OMAP3_DSP_MMU_Configuration

Deepali

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MMU mapping CMEM Buffers