TCI6638K2K: TCI6638K2K SRIO issue

Hi,

Do you use Processor SDK RTOS or are you using bare metal code to program the SRIO communication?

Best Regards,
Yordan

Hi,

Customers use C program language.

SRIO interface initialization code is reference code in TI.com:

C:\ti\pdk_keystone2_3_00_03_15\packages\ti\drv\srio\device\k2k\src\device_srio_loopback.c     SrioDevice_init()

Customer don't change the code.

After initialization, FPGA send the read/write request. 

Thanks!

Best Regards,

Rock Su

Rock,

Thanks for the info! We have little SRIO expertise left here. NREAD needs a response and SWRITE doesn't. What is the SRIO topology here? You have a K2K connected to 4 different devices each of one port? And 2 are doing the SWRITE, and another 2 are doing NREAD? Or the NREAD and SWRITE on the same FPGA device?

For SRIO user guide:  2.3.3 Message Passing

Out-of-order responses are allowed

Due to the nature of SRIO RETRY and out of order reception of message segments, the
requirement is that a type 11 message must use only one descriptor/buffer. Behavior of
the RXU is undefined if this is not the case. The SRIO only support Host Packet
descriptor types.

Regards, Eric

Hi,

Here are the suggestions from our SRIO expert:

-        If they want ordered transactions and better determinism, they need to think about the packets priorities and the LSUs that they are using.  There is a section in the user’s guide that talks about this, but from memory, they need to use the same LSU and same priority to guarantee in order delivery.

-        This is a packet based system, not TDM, so timing will change depending on loading with packets and number of ports used, etc.

-        If they want to force the NREADs first, make them higher priority than the NWRITEs.

-        They may also adjust the NREAD and/or SWRITE payload size per LSU write to see different results if latency is a concern.  They will have to play with it though.

they could play with the LSU shadow registers too.

Regards, Eric

Hi Eric,

The customer said they have tried your solution, the effect improved, but not significantly.

And at the same time, they also have some questions about your reply:

1. LSU: Does FPGA or DSP send LSU?

2. How to configure LSU shadow? 

At the same time, the customer wants to have a call with you...what do you think?

Best Regards,

Rock Su