[U-Boot-Users] TSEC Ethernet driver patch - RFC

[michael.firth at bt.com]

> -----Original Message-----
> From: Andy Fleming [mailto:afleming at gmail.com] 
> Sent: 15 January 2008 16:56
> To: Firth,MJC,Michael,DMJ R
> Cc: biggerbadderben at gmail.com; u-boot-users at lists.sourceforge.net
> Subject: Re: [U-Boot-Users] TSEC Ethernet driver patch - RFC
> 
> On Jan 9, 2008 2:26 PM,  <michael.firth at bt.com> wrote:
> >
> 
> So, for the most part, I'm happy with this change.  I suspect 
> that I over-engineered it, originally, anticipating the 
> possibility that a future part might make use of the other 
> mdio interfaces.
> 
> The biggest problem I see is that the TBI PHYs, which are 
> internal to each TSEC, are accessed through the other mdio 
> interfaces.  Right now this isn't really supported, but 
> there's a desire to expose these, since they are used for 
> SGMII configuration.  I hadn't yet figured out the best way 
> to do that, but this change would potentially make it more difficult.
> 
> Ideally, we would stop referring to PHYs only by address on the bus.
> There could be multiple busses (and, in fact, there are), so 
> the ideal solution would deal with that.  But that's a hefty 
> task (which I'm hoping Ben finds time for), so I'm not really 
> suggesting that for the short term.  For now it's probably 
> fine as long as it doesn't make Ben's job harder.  But it's 
> not really changing the higher-level interface, so that 
> should be ok, too.
> 
I guess a middle option is to make the two options (multi MDIO bus
support versus 
the ability to access all devices on a single MDIO bus) available via a
configuration option.

I think the way to do this from my patch is to instead retain the
'get_priv_for_phy' function 
within a #ifdef for the configuration option, and select whether to call
the function or always 
use the first TSEC instance, again based on the #define.

Given that, as you said, several people, have suggested that the whole
PHY support in U-Boot 
needs an overhaul, another question is whether any support for the
internal PHYs is likely to 
be implemented before this overhaul.

I guess that if the old functionality is still available within the
code, then, when the TBI 
support is implemented then the person that does that has easy access to
all the code options.

Regards

Michael