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Voyager
Voyager
7,859 Views
Registered: ‎04-21-2014

Important but missing feature Vivado -> SDK

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Vivado using the AXI Direct Memory Access 7.1 in IPI seems to be missing a crucial feature. That is, the setting for the "Width of Buffer Length Register" parameter in the IP customization GUI doesn’t seem to be forwarded to SDK with the hardware platform.

 

Inside the SDK project, you can use Xilinx sample code to generate and initialize a structure with MaxTransferLen, but it is always set to 0x7FFF in the structure TxBdRing (even though SG is disabled?). It is the wrong value. Furthermore, I can see no evidence that the value of the "Width of Buffer Length Register" parameter shows up in the "xparameters.h" file. (I don’t see any evidence of 0x4000, 0x3FFF, or 14 in the file).

 

If this parameter changes between builds, and the firmware developer isn’t automatically informed via the normal mechanisms (e.g., xparameters.h), bad things can ensue.  This parameter has a direct impact on meeting STA objectives, and sometimes needs to be adjusted by users as part of overall technical compromises.

 

This is a request to add the parameter via #define in the xparameters.h, or to inform me how software can know, from within SDK, what the value of the Width of Buffer Length Register is.  (Maybe I am missing something)

***Many of us who help you are just FPGA enthusiasts, and not Xilinx employees. If you receive help, and give kudos (star), you're likely to continue receiving help in the future. If you get a solution, please mark it as a solution.***
AXIDMA7_1.gif
maxTransferLength.gif
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Newbie anirudh
Newbie
14,389 Views
Registered: ‎12-20-2013

Re: Important but missing feature Vivado -> SDK

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Hi,

I am the manager for the SW team responsible for this driver.

Thanks for bringing this up.

 

We missed exposting this parameter to xparameters.h.

This will be fixed for our next release which is 2016.2 (June 2016).

 

regards

 

5 Replies
Voyager
Voyager
7,691 Views
Registered: ‎04-21-2014

Re: Important but missing feature Vivado -> SDK

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Hello @austin

I took the time to take screen shots and format a post on this forum, as much for Xilinix's benefit as for mine.  Perhaps I just posted to the section of the forum not monitored by xilinx staff.  Could you move this to the correct section and also see if any officially responsible xilinx staff member has a comment.  A "we're looking into it after verifying the issue, and have it on the 'to do' list of fixes, fix date unknown at this time" or a "what do you mean by ____" wuold go a lot further than silence.  Seems a shame that Xilinx has created this system and pushed its user base into it but a post like this gets zero response. 

 

I can send you a link via PM to a large company that is handling forums very well, even having their top technical person participating on a public form that his employer doesn't control.  It can be done sucessfully--more so since this a Xilinx owned and operated forum--but it takes more than some php coding--it takes follow through.  It would nice to see some follow through on the tough questions posted on this forum, and not just the easy ones that university students and researchers post.

***Many of us who help you are just FPGA enthusiasts, and not Xilinx employees. If you receive help, and give kudos (star), you're likely to continue receiving help in the future. If you get a solution, please mark it as a solution.***
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Scholar austin
Scholar
7,688 Views
Registered: ‎02-27-2008

Re: Important but missing feature Vivado -> SDK

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m,

 

The moderator of this board should pick this one up.  If not, I have also notified their supervisor.

 

We watch other forums, and I have to say that ours is definitely up there as being "best in class" and we are always looking for ways to improve, too.

 

Understand that Xilinx relies on our local distributors as well for answering questions, and providing help locally.  I would definitely spend some time getting to know your local support person, as they can be extremely helpful.  For your question (missing?), that goes to the heart of the software team, and it is never easy to get them to look at a customer issue.  In your case, it may be something very simple that you missed (I do not know).

 

 

 

 

Austin Lesea
Principal Engineer
Xilinx San Jose
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Voyager
Voyager
7,671 Views
Registered: ‎04-21-2014

Re: Important but missing feature Vivado -> SDK

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Thanks @austin:

 

>Understand that Xilinx relies on our local distributors as well for answering questions, and providing help locally. 

 

I get pretty good support from the FAEs and distributor FAEs, and from time to time give them support if I can.  As you know, it is impossible for one person to know everything about all xilinx parts and all xilinx tools. 

 

This particular post really isn't an FAE issue, as I have a work around.  It is more of a bug report for my commrades in the "community" to track and see what other workarounds might exist from Xilinx or others.  Hopefully it will get logged as a bug report/feature request.  Ideally, if there was a problem with my understanding and not the tools (I don't think there is in this case) somebody would correct me.  I'd welcome that.

 

In any event, XIlinx technology is great.  However, if there is no standard and easy path for the type of quality feedback in the original post, Xilinx is going open loop.  Open loop in this context is not a good thing.  I'm not whinning, I'm trying to help improve Vivado with this report. 

 

I understand Xilinx's stance on support.  It doesn't make a lot of finincial sense to spend time supporting people who have no viable path to buying parts in large numbers.  (That does not include me.)  So I am not complaining.  But I'm trying to do the right thing here, and the time I am spending is a donation.

 

My work around is to just shrug and put a comment on the IPI letting future engineers know that changing the parameter will require out of band communication with the firmware developer.  If there is a better work around, I'm happy to recieve that feedback. 

***Many of us who help you are just FPGA enthusiasts, and not Xilinx employees. If you receive help, and give kudos (star), you're likely to continue receiving help in the future. If you get a solution, please mark it as a solution.***
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Newbie anirudh
Newbie
14,390 Views
Registered: ‎12-20-2013

Re: Important but missing feature Vivado -> SDK

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Hi,

I am the manager for the SW team responsible for this driver.

Thanks for bringing this up.

 

We missed exposting this parameter to xparameters.h.

This will be fixed for our next release which is 2016.2 (June 2016).

 

regards

 

Voyager
Voyager
7,285 Views
Registered: ‎04-21-2014

Re: Important but missing feature Vivado -> SDK

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Thanks @anirudh, good to know its on the list and radar.

***Many of us who help you are just FPGA enthusiasts, and not Xilinx employees. If you receive help, and give kudos (star), you're likely to continue receiving help in the future. If you get a solution, please mark it as a solution.***
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