SRIO failed after several successful transmissions

gaotai zhang

Hello,

I'm using the TI breakout board to connect two evms, evm6678 and evm6670. I wanted to get some knowledge about the transmission delay of SRIO, so I send a packet from evm6678 to evm6670, after receiving, 6670 sends back a packet to 6678, the time between sending and receiving on 6678 was measured, which was aproximately transmission delay doubled. Also, I wanted to do it several times to get the average.

The 6678 board successfully sent 3 packets and received 3 response packets from 6670. On the fourth time, 6678 sent out a packet, 6670 received and sent back response packet, but 6678 never received the packet and hung at the sockRecv call .

According to RandyJ's post, I checked several registers both on 6670 and 6678 after sockSend call, the results are the same and as follows:

transmission no	ERR_STAT	LM_RESP	ERR_DET	SP0_CTL
1	0x20202	0x80000005	0x0	0x600001
2	0x20202	0x5	0x0	0x600001
3	0x20202	0x5	0x0	0x600001
4	0x20202	0x5	0x0	0x600001

Since the first 3 transmission loops are succesful, I think the configuration of routing is correct, I cleared the rx buffer after sockRecv call.

That's about all the information I can think of now, Let me know if you need more information to help with my problem. Thanks.

Roy

over 12 years ago

0 Elush Shirazpour over 12 years ago

TI__Intellectual 2790 points

Roy

Are you using DIRECT IO and LSU registers to send the information?

Thanks

Elush

0 gaotai zhang over 12 years ago in reply to Elush Shirazpour

Intellectual 415 points

Elush,

I'm using message passing and the packet type is type11.

0 Elush Shirazpour over 12 years ago in reply to gaotai zhang

TI__Intellectual 2790 points

Roy,

What is the byte_count of the data you send? How do you configure the message passing?

It is highly advised that you use Direct IO. Message passing is used when "a destination address is not specified," but you know the destination addresses to both the C6678 and C6670.

Thanks

Elush

0 gaotai zhang over 12 years ago in reply to Elush Shirazpour

Intellectual 415 points

Elush,

Good news, I used to set my packet size to 256 bytes, when I changed that to 128 bytes, the problem was solved. Now I can send and receive packet to continue my test, however, I think that 256 bytes is certainly an available option since I've seen packets configured with size 256 in demo programs. Which registers should I check to figure it out?

Thanks

Roy

0 Elush Shirazpour over 12 years ago in reply to gaotai zhang

TI__Intellectual 2790 points

Roy,

Glad you fixed the problem. You can check under the ERROR MANAGEMENT REGISTERS for any errors reported by SRIO.

Elush

0 Alexey Naydenov over 12 years ago in reply to gaotai zhang

Intellectual 420 points

Not sure if it has anything to do with your problem but there is errata for c6678 Usage Note 12:

In the silicon revision(s) listed, the PKTDMA in the SRIO and PA_SS blocks requires
the RX descriptor buffer size to be at least one byte larger than the output payload data
sent in the buffer. If the RX buffer is equal in size to the output payload data, the
PKTDMA will use an extra RX descriptor which it will link to the RX descriptor, even
though there will be no output data placed in the extra descriptor’s buffer.

Workaround:

One workaround is to size the RX descriptor buffers so they are at least one byte larger
than the maximum expected output payload data size.
Another workaround is to allocate enough extra RX descriptors with associated buffers
to make up for the extra ones that will be required when the RX descriptor buffer is
equal in size to the output payload data.

0 gaotai zhang over 12 years ago in reply to Alexey Naydenov

Intellectual 415 points

Thanks, Alexey,

I used the first workaround and changed SRIO MTU to 257 Bytes in my case, then I succeded in sending 256B packets.

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SRIO failed after several successful transmissions