Subject: RE: TSI ethernet PHY question

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 24 May 2007 08:52:07 +1000

> On power up, because this pin is pulled high by the LED, the
> TXC_RXC_DELAY mode is enabled, causing a 1.9ns delay between the clock
> and data on the GMII interface. Tsi109 could not operate properly with
> this delay. The TXC_RXC_DELAY mode has to be disabled by software.
> 
> If the Quality/TXC_RXC_DELAY pin is left not connected PHY will work in
> normal mode without delay and therefore the workaround is not required.

Ok, so this is a workaround that is specific to the Holly board...
interesting. I have to figure out what is the best way of having it in a
"generic" PHY driver for the BCM5461A chip.

Right now, we're seeing a problem where the driver doesn't detect a link
up. It detects the link at boot fine. If we disconnect the cable, it
sees the link going down, but it never sees the link going back up. I
haven't investigated much yet but I wanted to understand this workaround
in case it could be related.

> I think that for situations like one on the Holly board we may need
> board-specific hooks which modify normal initialization. As in our case:
> no LED - no trouble.

Yes, I need to look into that.

> I have put into my plans switching Tsi108/9 driver to common PHY lib
> (after Josh released his patch for Holly) but it looks like you will
> beat me here - I still have to close some other tasks. Let me know if I
> can help with anything around Tsi109.

We'll see, I said I'm contemplating the idea, doesn't mean I'll actually
do it anytime soon :-)

Cheers,
Ben.