Re: [PATCH net-next v4 RESEND] stmmac: tegra: Add MGBE support

Hi Florian,

On 12/10/2022 05:56, Bhadram Varka wrote:

...

quoted

You should be modeling this as a proper PCS driver and have a 'pcs-handle'
property pointing to it in your Device Tree.

The configuration you are doing here is probably working the first time you
bring-up the network device but I doubt it works across system
suspend/resume states where power to the GMAC and PCS is lost, it also
begs the question of which mediums this was tested with and whether
dynamic switching of speeds and so on is working?
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For Tegra234, there is UPHY lanes control logic inside XPCS IP which is memory-mapped IP (not part of the MAC IP).
mgbe_uphy_lane_bringup performs UPHY lane bring up here. Here MGBE/XPCS works in XFI mode.

Agree that lane bring down logic is not present interface down/suspend paths. Will update the changes accordingly.
One more thing is that UPHY lane bring should happen only after the line side link is up. This also will make the changes.
Please let me know if I miss anything here.

An updated version of this has now been posted [0]. It should have been 
marked as 'V5'. We have tested suspend/resume and verified that it is 
working. We are hoping to get this into Linux v6.2 if not too late. Let 
me know if you have any concerns.

Thanks
Jon

[0] 
https://lore.kernel.org/linux-tegra/20221118075744.49442-1-ruppala@nvidia.com/T/#t (local)

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nvpublic