RE: [RESEND PATCH net-next v4 0/3] Enable 2.5Gbps speed for stmmac

From: Sit, Michael Wei Hong
Date: Thu Jun 03 2021 - 09:43:18 EST


Vladimir,

> -----Original Message-----
> From: Vladimir Oltean <olteanv@xxxxxxxxx>
> Sent: Thursday, June 3, 2021 9:28 PM
> To: Russell King (Oracle) <linux@xxxxxxxxxxxxxxx>
> Cc: Sit, Michael Wei Hong <michael.wei.hong.sit@xxxxxxxxx>;
> Jose.Abreu@xxxxxxxxxxxx; andrew@xxxxxxx;
> hkallweit1@xxxxxxxxx; kuba@xxxxxxxxxx;
> netdev@xxxxxxxxxxxxxxx; peppe.cavallaro@xxxxxx;
> alexandre.torgue@xxxxxxxxxxx; davem@xxxxxxxxxxxxx;
> mcoquelin.stm32@xxxxxxxxx; Voon, Weifeng
> <weifeng.voon@xxxxxxxxx>; Ong, Boon Leong
> <boon.leong.ong@xxxxxxxxx>; Tan, Tee Min
> <tee.min.tan@xxxxxxxxx>; vee.khee.wong@xxxxxxxxxxxxxxx;
> Wong, Vee Khee <vee.khee.wong@xxxxxxxxx>; linux-stm32@st-
> md-mailman.stormreply.com; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [RESEND PATCH net-next v4 0/3] Enable 2.5Gbps
> speed for stmmac
>
> Michael,
>
> On Thu, Jun 03, 2021 at 02:08:51PM +0100, Russell King (Oracle)
> wrote:
> > Hi,
> >
> > On Thu, Jun 03, 2021 at 07:50:29PM +0800, Michael Sit Wei Hong
> wrote:
> > > Intel mGbE supports 2.5Gbps link speed by overclocking the
> clock
> > > rate by 2.5 times to support 2.5Gbps link speed. In this mode,
> the
> > > serdes/PHY operates at a serial baud rate of 3.125 Gbps and
> the PCS
> > > data path and GMII interface of the MAC operate at 312.5
> MHz instead of 125 MHz.
> > > This is configured in the BIOS during boot up. The kernel
> driver is
> > > not able access to modify the clock rate for 1Gbps/2.5G mode
> on the
> > > fly. The way to determine the current 1G/2.5G mode is by
> reading a
> > > dedicated adhoc register through mdio bus.
> >
> > How does this interact with Vladimir's "Convert xpcs to
> phylink_pcs_ops"
> > series? Is there an inter-dependency between these, or a
> preferred
> > order that they should be applied?
> >
> > Thanks.
>
> My preferred order would be for my series to go in first, if
> possible, because I don't have hardware readily available to test,
> and VK already has tested my patches a few times until they
> reached a stable state.
>
> I went through your patches and I think rebasing on top of my
> phylink_pcs_ops conversion should be easy.
>
> Thanks.
Sure! I am okay to let you merge your codes and rebase my changes later on
Do let me know when I can start rebasing and send in the next revision