How long does it take for the entire process of Stratix 10 CvP Update?

[HTong1]

​Hi, copied below is from Intel document that indicates that for every 4KB of configuration data, CVP_CREDIT shall be polled, and Stratix 10 CvP reponse can take typically 5 sec to maximum 1 min. What does it mean? Is the 5 sec for every polling of the CVP_CREDIT for every 4KB? If so, and if the .rbf file is 32MB, the entire process could take as long as (32MB/4K) * 5sec = 8K * 5 sec that is more than 20 hours! Please clarify what the 5sec and 1min mean exactly. Thanks.

----- copied from Intel document --------

When you poll the CVP_CREDIT bits from the CvP credit register, you must write

the next 4KB of fabric configuration data to the CvP data register within 50 ms of

receiving an additional credit. Failure to send the data results in configuration

failure.

• The CvP response time is variable and depends on different conditions. The typical

delay time is 5 sec and it is safe to wait till 1 min. So the driver should poll status

in credit register to decide on driver timeout.

[JohnT_Intel]

Hi, When you poll the CVP_CREDIT then you will need to provide the 4KB of bitstream data within 50ms. The CvP response time is that after sending the 4KB data, you will need to wait around 5sec to 1 min in order for you to get the response or status update.

[HTong1]

​Hi, would you clarify what is exactly the response or status update? Is it the response or status update for the availability of the CVP_CREDIT? I try to estimate how long it takes for CvP Update to complete a 32MB .rbf file, the minimum, typical, and the maximum. 32MB is uncompressed. If a compressed .rbf file can be used, how long it would take. Thanks.

[HTong1]

​Does anyone have experience of CvP Update on Stratix 10? Just from Intel's ug_s10_cvp.pdf and the copies paragraph from the OP, typically for CvP Update of 32MB .rbf it would take (32MB/4KB) * 5 sec / 3600 sec/hour that is more than 10 hours, or maximum 1 min / 5 sec times the typical that is 200 hours!

[JohnT_Intel]

Hi, That is only if you need to polled for status. If you are just only keep on sending the 32MB .rbf file with each 4KB data without checking the status then it will be completed very fast. You do not need to polled the status until all the 32MB .rbf file is completed.

[HTong1]

​Polling of the CVP_CREDIT and error status are documented in the Intel document and it seems that they are required. If none of the polling of the CVP_CREDIT and error status is required, Intel may need to update the document. It is questionable why the CPV_CREDIT register exists in the driver flow and if the error status polling is skipped whether the error status in any 4KB transfer will stick to the end of the process.

If both CVP_CREDIT and error status could be skipped, at least the error status at the end of the CvP Update process needs to be polled, and in this case, it will take at least 1 min to find out whether there is any error unless there exists a register bit to indicate that the status is ready. Is there any such register bit?

[JohnT_Intel]

The delay to read the CVP Credit register is at least 5 sec. For the CVP Status register, it is not impacted. If there is any issue during CvP then the CvP status register will be directly updated.