Subject: Re: [PATCH net-next 0/2] net: mediatek: Add MT7621 TRGMII mode support

From: Andrew Lunn <[email-masked]>
Date: Mon, 17 Jun 2019 23:44:28 +0200

On Mon, Jun 17, 2019 at 09:33:12PM +0000, René van Dorst wrote:
> Quoting Andrew Lunn <[email-masked]>:
> 
> >On Sun, Jun 16, 2019 at 08:20:08PM +0200, René van Dorst wrote:
> >>Like many other mediatek SOCs, the MT7621 SOC and the internal MT7530
> >>switch both
> >>supports TRGMII mode. MT7621 TRGMII speed is 1200MBit.
> >
> >Hi René
> >
> 
> Hi Andrew,
> 
> >Is TRGMII used only between the SoC and the Switch? Or does external
> >ports of the switch also support 1200Mbit/s? If external ports support
> >this, what does ethtool show for Speed?
> 
> Only the first GMAC of the SOC and port 6 of the switch supports this mode.
> The switch can be internal in the SOC but also a separate chip.
> 
> PHYLINK and ethertool reports the link as 1Gbit.
> The link is fixed-link with speed = 1000.
> 
> dmesg output with unposted PHYLINK patches:
> [    5.236763] mt7530 mdio-bus:1f: configuring for fixed/trgmii link mode
> [    5.249813] mt7530 mdio-bus:1f: phylink_mac_config:
> mode=fixed/trgmii/1Gbps/Full adv=00,00000000,00000220 pause=12 link=1 an=1
> [    6.389435] mtk_soc_eth 1e100000.ethernet eth0: phylink_mac_config:
> mode=fixed/trgmii/1Gbps/Full adv=00,00000000,00000220 pause=12 link=1 an=1

With PHYLINK, you can probably set the fixed link to the true 1.2Gbps.

> # ethtool eth0
> Settings for eth0:
>          Supported ports: [ MII ]
>          Supported link modes:   1000baseT/Full
>          Supported pause frame use: No
>          Supports auto-negotiation: No
>          Supported FEC modes: Not reported
>          Advertised link modes:  1000baseT/Full
>          Advertised pause frame use: No
>          Advertised auto-negotiation: No
>          Advertised FEC modes: Not reported
>          Speed: 1000Mb/s

We could consider adding 1200BaseT/Full?

   Andrew