Re: [PATCH v2 3/4] net: stmmac: Add glue layer for Loongson-1 SoC

[Keguang Zhang]

On Tue, Aug 22, 2023 at 11:20 PM Andrew Lunn <andrew@xxxxxxx> wrote:
>
> > > What about the other three RGMII modes? Plain rgmii is pretty unusual,
> > > rgmii-id is the most used.
> > >
> > According to the LS1B datasheet, only RGMII and MII are supported.
> > And I can confirm that MII mode does work for LS1B.
>
> What does your device tree look like? What are you setting phy-mode to
> in the rgmii case? As i said, "rgmii" is pretty unusual, you normally
> need "rgmii-id".
>
> Something in the system needs to add 2ns delays to the RGMII clock
> lines. Generally in device tree you pass phy-mode = "rgmii-id"; The
> MAC configures itself for RGMII, and passes
> PHY_INTERFACE_MODE_RGMII_ID to the PHY when it is attached. The PHY
> then inserts the delays.
>
> What is inserting the delays in your system?
>
I understand the delay issue of RGMII.
Just tried phy-mode = "rgmii-id", it still works.
I will use PHY_INTERFACE_MODE_RGMII_ID instead.
Thanks!

>      Andrew
>


-- 
Best regards,

Keguang Zhang