[U-Boot] [RFC PATCH] net: gem: Add support for more PHYs on MDIO bus

[Michal Simek]

Hi Joe,

On 2.2.2018 20:35, Joe Hershberger wrote:
> Hi Michal,
> 
> On Thu, Feb 1, 2018 at 6:42 AM, Michal Simek <michal.simek at xilinx.com> wrote:
>> Find out MDIO bus and enable MDIO access to it if this is done via
>> different controller.
>>
>> Signed-off-by: Michal Simek <michal.simek at xilinx.com>
>> ---
>>
>> Hi Joe,
>>
>> this is the code I have hacked a year ago for ZynqMP where we can have
>> configuration that 4 gems are enabled but they share the same MDIO bus
>> which can be assigned to only gem. Normally recommendation is that you
>> should assign it to IP which is required for boot and this is suitable I
>> would say for almost everybody.
>> But for testing purpose it will be good to support sharing mdio bus
>> between others IPs. This hack is "enabling" this for others gem but not
>> across different ethernet drivers.
> 
> Seems practical.
> 
>> And my question is if there is any solution which can be used now for
>> handling it. Or even this should work even now but we do something
>> wrong.
> 
> I would envision some DM way to model the NIC, the MDIO bus, and the
> PHY separately. The big roadblock is that the DTS format is different
> for every NIC.

Is it really that different? There should be phy handle which is
pointing to actual phy and that should be enough to recognize parents
and IP responsible for MDIO bus.


>> I am refreshing this topic based on communication with Tomasz
>> Gorochowik when he wanted to separate mdio part but it is not compatible
>> with solution used in Linux which is pattern we should follow.
> 
> We do the same thing on our 7020 products.

What exactly are you doing on 7020?

Thanks,
Michal