LAN Trouble (probably concerned with Vybrid errata e6358 )

cancel
Showing results for 
Search instead for 
Did you mean: 

LAN Trouble (probably concerned with Vybrid errata e6358 )

Jump to solution
506 Views
makotokatsukura
Contributor II

Dear forum members,

 

  We are facing LAN trouble now. We are using Vybrid VF5 chip and Timesys Linux(3.0) on our prototype.We think the trouble relates to Vybrid errata e6358. The symptom is as follows:

 

(Symptom)

  1. When our software sent 4500 bytes TCP packets repeatedly (one packet every 1 second) from Vybrid to our host computer, the throughput gradually got worse.  At the worst case, we had to wait 60 seconds to complete sending only 1 packet.
  2. The total size of the packet is longer than Maximum Segment Size (MSS). That means the packet is divided into small packets. In this case, the packet was divided into 4 small packets.
  3. We debugged the linux LAN driver ( linux-3.0/drivers/net/fec.c ) and we found packet send trigger (= set TDAR register) for the second divided packet was ignored by Vybrid.

 

(Condition)

  1. The packet is TCP protocol.
  2. The host computer replied the ACK packet immediately after received the first divided packet.

 

We think this issue is related to the Vybrid errata e6358, “ENET: Write to Transmit Descriptor Active Register (ENET_TDAR) is ignored”. We made a patch to avoid that errata (the patch is attached to this message), then the trouble does not occur after the modification.

 

We are not so familiar with both linux driver and Vybrid so please give us the comment whether our patch is designed appropriately.

 

Best regards,

Makoto Katsukura

 

 

Referense:

  Vybrid Errata ( Vybrid 1N02G )

http://cache.freescale.com/files/32bit/doc/errata/VYBRID_1N02G.pdf

Original Attachment has been moved to: 20131114_fec.patch.zip

Labels (3)
Tags (4)
0 Kudos
1 Solution
168 Views
timesyssupport
Senior Contributor II

Hello Katsukura-san,

Thank you for providing a description of the problem and the attached patch. We will review this submission, and following a successful review will add the patch to the current Vybrid kernel source tree. I will let you know when we have completed this, or if we have any additional questions.

Regards,

Timesys Support

View solution in original post

0 Kudos
2 Replies
169 Views
timesyssupport
Senior Contributor II

Hello Katsukura-san,

Thank you for providing a description of the problem and the attached patch. We will review this submission, and following a successful review will add the patch to the current Vybrid kernel source tree. I will let you know when we have completed this, or if we have any additional questions.

Regards,

Timesys Support

0 Kudos
168 Views
karina_valencia
NXP Apps Support
NXP Apps Support

timesyssupport can you  help to  check this case?

0 Kudos