Tom, et. al.
When I first started playing with my board, I also was having difficulty TFTP which at one point I attributed to speed issues, it turned out it wasn't speed, but "other" traffic.
After a lot of playing around and searching around the web, I was able to find out that u-boot on the MPC8313E-RDB board is extremely sensitive to other traffic on a network. There were posts on the Blackfin processor site saying that u-boot would fail in cases where it received other traffic on a network and would fail at all speeds. It appears also that they were able to fix it by changing the u-boot code to be less sensitive to other traffic being received, but I couldn't find any follow ups if it ever made it back into the main u-boot source tree. The symptom you get is where when running TFTP you get so many timeouts that it fails.
The key for me turned out that u-boot TFTP can be made reliable, but only if you do a direct back to back connection between the target board and the TFTP host. In that case, you may get an initial timeout, but after that, it downloads fine. It also works on either ETSEC and works at both 100 MBPS and 1 GBPS connections. So you should not have to change the speed to get TFTP to work. If you notice all the instructions and samples from Freescale always tell you to directly connect, so if you are not doing that, I highly recommend you don't TFTP with the current u-boot SW on a network connection (unless you can guarantee the target board doesn't receive other spurious traffic).
Another thing to note is that when it comes to ETSEC1 (called TSEC0 under u-boot) is connected to a Vitesse switch chip on the board, so from what I can tell, that port always runs at 1 GBPS, but the actual 5 physical ports on the board will run OK and automatically at 1 GBPS, 100 MBPS or even 10 MBPS and the switch chip will take care of the speed mismatch.
In the case of ETSEC2 (TSEC1 under u-boot), it is not connected to a switch, so if you plug a 100 MBPS connection into it, it will auto-negotiate from 1 GBPS to 100 MBPS (or 10) and also report that speed under u-boot.
Hope this helps,
Alan
P.S. Wouldn't it have been nice if the numbering of the ports between Linux, u-boot and the Freescale chip were the same? It certanly adds to the confusion.