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DSP AMMU setup from the ARM-A9

dave carlson
Prodigy 185 points
Other Parts Discussed in Thread: 4430

I would like to have a DSP program loader setup the DSP code in a locked down memory environment (so that the DSP cannot write on "others" memory nor execute non-executable sections nor write to read-only sections).

In the 4430 TRM (Rev AA) I do not see a way that the DSP AMMU can be programmed from the ARM-A9 -- thus the DSP would need to be a party to setting up its own sandbox. 

This would also require the DSP to have knowledge of its elf sections addresses and extents (for eXec and Read-only page protection).

If there is a way to setup the DSP AMMU from the ARM-A9 that I have missed?  (or is the security model of the DSP dependent on code that can only execute on the DSP?)

 tkx

dave

  • 0
    TI__Expert 8055 points

    Dave,

    The DSP MMU is located on the boundary with the L3 and is programmed by the A9.  The A9, in programming the DSP MMU, can restrict the DSP's access to certain memory regions.  The DSP MMU acts as a gatekeeper, so if the AMMU tries to program a region not allowed by the DSP MMU, a fault will occur.  Since the details of the DSP MMU are not in the public domain, you will need to contact your TI representative directly for more specific information.

    Regards,

    Gina