Hi Mike,

[...]
> The hang is in wait_for_user_access() in the davinci_mdio_read() call.  Looks like
> the state machine got put back into IDLE somewhere between the MDIO probe and the 
> EMAC probe. Seems like there should be some sort of time-out and error message 
> in the wait_for_user_access() method.... (maybe even a check for IDLE??)
> 
> If I add a patch to check the state machine for IDLE and then re-enable it in the
> davinci_mdio_read() call, it is able to press on and come up.  I don't see any calls
> to the davinci_mdio_suspend() call, so I am wondering if the EMAC probe routine, 
> particularly the application of the SOFTRESET, is causing the MDIO to drop back to 
> IDLE / disabled.
> 
> I can post the patch if you like, but it is a bit of a hack...

An EMAC soft-reset clobbering the MDIO controller state is a
possibility.  I will poll TI designers to see if this could be the case.

In any case, a couple of unanswered questions remain:

  1. Why don't other davinci devices display similar behavior?

  2. If the answer to #1 above is that the timing window is pretty slim
     (i.e., only if an MDIO read/write is in progress during EMAC
     soft-reset), why do we hit this situation consistently on
     mityomap?

I have put together a quick patch (tested dm365).  See attached.

Regards
Cyril.