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Visitor mbrainin
Visitor
8,405 Views
Registered: ‎07-09-2015

OpenAMP with OCM

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Hi,

 

I've been using an AMP design using the previous methodology (ug1078 & ug1079).

I have linux running running on cpu 0 and baremetal on cpu1 and they communicate via the OCM. Simple.

 

With the latest openAMP (ug1186) using the remote proc, is the OCM still available to be used as shared memory. I know there is rpmsg, but is the OCM also available?

 

Thanks,

Misha

 

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Visitor mbrainin
Visitor
15,889 Views
Registered: ‎07-09-2015

Re: OpenAMP with OCM

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Hi Grabi,

 

Thanks for your reply.

I was able to get openAmp working and it does not seem to effect the OCM at all.

Just remember to disable the cache when using it.

 

Let me know if run into any issues.

 

Misha

 

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6 Replies
Contributor
Contributor
8,337 Views
Registered: ‎02-24-2016

Re: OpenAMP with OCM

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Hi Misha,

 

Unfortunately, I don't know the answer but I'm looking forward to same thing. So please, if you find something...write it here!

 

I'm my case, rpmsg seems to be a bit too much for my baremetal app. I need something simpler and that does not stuck trying to read when I do not send data...the approach of xapp1078 seems pretty efficient for small data tx...but OpenAmp gives a pretty cool approach to use AMP.

 

Today, I will try to do what you proposed. I'll come back if I get some results.

 

Good luck!

Garbí

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Visitor mbrainin
Visitor
15,890 Views
Registered: ‎07-09-2015

Re: OpenAMP with OCM

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Hi Grabi,

 

Thanks for your reply.

I was able to get openAmp working and it does not seem to effect the OCM at all.

Just remember to disable the cache when using it.

 

Let me know if run into any issues.

 

Misha

 

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Contributor
Contributor
8,273 Views
Registered: ‎02-24-2016

Re: OpenAMP with OCM

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Hi Misha, thx for your message,

 

Yes, indeed, it looks like I can use OCM to tx messages without issues... Looks too easy though, xD.

 

One open question I have (not completely related to this thread) is about OCM itself. I don't really know how to explicitly make use of it, but that's another story.

Now, as you mention, I just have to uncache the part I want to use for comm, the baremetal does not use it...and for linux I have to do some kind of mmap. If you could point me to some documentation, it'd be great, in the meantime I'll continue googling!

 

Thanks again,

Best regards,

Garbí

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Contributor
Contributor
8,093 Views
Registered: ‎02-24-2016

Re: OpenAMP with OCM

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Hi again,

 

I was doing further testing and I saw some weird behaviour that most likely is related to the use of OCM. Digging a bit in the forum I found this:

https://forums.xilinx.com/t5/Embedded-Linux/XAPP1078-OCM-Pool-Conflict/m-p/592542/highlight/true#M12641

 

In my case, I also see how linux allocates the 256 kB...

 

DMA: preallocated 256 KiB pool for atomic coherent allocations
zynq-ocm f800c000.ocmc: ZYNQ OCM pool: 256 KiB @ 0x90880000

 

 

How did you solve this issue...? Any suggestions are more than welcome.

Thanks,
Garbí

 

 

 

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Contributor
Contributor
7,704 Views
Registered: ‎02-24-2016

Re: OpenAMP with OCM

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Ok, false alarm, :-/
Everything looks fine now. My problem was related to other stuff (vdma interrupts).
Just in case you're interested...
https://forums.xilinx.com/t5/OpenAMP/Corrupted-memory-when-probing-remoteproc-OpenAmp/td-p/694850

Right now, I continue using OCM for IPC and everything looks pretty good.

Best regards,
Garbí
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Adventurer
Adventurer
4,430 Views
Registered: ‎09-28-2016

Re: OpenAMP with OCM

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Hi,Misha

    I am a green hands to the AMP, I have some doubt to consult you.

 

    1.what the difference between amp and openamp, I am ready to use openamp with ug1186 rather than amp.

    2.which methodology are you using? amp or openamp?

    3.when I followed the document ug1186-zynq-openamp-gsg.pdf, step to step, and I found some issues.I think this 

      document isn't detail, how can I do?

 

    Thanks a lot, I am looking forward to you reply!!!

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