8360 custom board, ucc_geth TX errors on longer(?) packets

Steven Hein ssh at sgi.com
Sat Feb 2 09:06:15 EST 2008

Steven Hein wrote:
> Kim Phillips wrote:
>> On Fri, 01 Feb 2008 12:52:25 -0600
>> Steven Hein <ssh at sgi.com> wrote:
>>> The one main difference in this board is how eth0 is wired.
>>> We have a Broadcom GbE switch part, and UCC1 eth is wired
>>> directly to that switch (no PHY).   (This where I needed to
>> sounds like you ran into some h/w errata.  if on rgmii, you might
>> want to find a way to program the switch for rgmii with internal delay
>> (8360 rev.2 rgmii-id rx & tx; 8360rev2.1 rgmii-rxid (i.e. for rx
>> only)).  If not, I'd contact fsl tech support directly.
>> Kim
> I would suspect HW.....but this WORKS with the 2.6.16 kernel
> I was using!    That's why I suspect that I still don't have
> something configured right in my device tree, or something
> else I missed in the new kernel.    But I can't
> figure out what it is.... :-(    I've poured over the code in
> the old versus new (both the ucc_geth driver and the platform
> initialization in the old, and the device tree in the new)
> and can't figure out what I missed!   And like I said, a
> kernel with the same config (other than changing the platform)
> works on my MPC8360E-MDS board.   Granted, that doesn't have
> this direct switch connection......
> I did look at the code related to the HW errata (QE_ENET18).
> But we're using GMII to the switch....and that workaround
> code wasn't in active in my old kernel (it was there, but
> commented out).
> Any other thoughts?    Has anyone seen this symptom before?
> Steve
Okay....I found it!    Started poking at the UCCE registers
and found that the FIFO sizes weren't right.   This led me
to find a bug in my ucc_geth interface to the fixed-link
PHY driver:  the code to reconfigure the MURAM FIFO's for
Gigabit operation wasn't being executed for no-phy configs!
All is well once I changed this.

Sorry for the noise.....   (glad I found this before
submitting my patch!   ;-)


Steve Hein (ssh at sgi.com)              Engineering Diagnostics/Software
Silicon Graphics, Inc.                          
1168 Industrial Blvd.                 Phone: (715) 726-8410
Chippewa Falls, WI 54729              Fax:   (715) 726-6715

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