On Mon, Sep 05, 2022 at 06:41:33PM -0700, Tao Ren wrote:
> Hi Andrew,
>
> On Tue, Sep 06, 2022 at 02:22:50AM +0200, Andrew Lunn wrote:
> > On Mon, Sep 05, 2022 at 04:56:34PM -0700, rentao.bupt@xxxxxxxxx wrote:
> > > From: Tao Ren <rentao.bupt@xxxxxxxxx>
> > >
> > > Enable mac3 controller in Elbert dts: Elbert MAC3 is connected to the
> > > onboard switch directly (fixed link).
> >
> > What is the switch? Could you also add a DT node for it?
> >
> > >
> > > Signed-off-by: Tao Ren <rentao.bupt@xxxxxxxxx>
> > > ---
> > > arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts | 11 +++++++++++
> > > 1 file changed, 11 insertions(+)
> > >
> > > diff --git a/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts b/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > > index 27b43fe099f1..52cb617783ac 100644
> > > --- a/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > > +++ b/arch/arm/boot/dts/aspeed-bmc-facebook-elbert.dts
> > > @@ -183,3 +183,14 @@ imux31: i2c@7 {
> > > &i2c11 {
> > > status = "okay";
> > > };
> > > +
> > > +&mac3 {
> > > + status = "okay";
> > > + phy-mode = "rgmii";
> >
> > 'rgmii' is suspicious, though not necessarily wrong. This value is
> > normally passed to the PHY, so the PHY inserts the RGMII delay. You
> > however don't have a PHY. So i assume the switch is inserting the
> > delay? Again, being able to see the DT properties for the switch would
> > be useful.
> >
> > Andrew
>
> Thank you for the quick review!
>
> The BMC mac3 is connected to BCM53134P's IMP_RGMII port, and there is no
> PHY between BMC MAC and BCM53134P. BCM53134P loads configurations from
> its EEPROM when the chip is powered.
So i assume you have the switch RGMII port doing the delays. That is
fine.
> Could you please point me an example showing how to describe the switch in
> dts? Anyhow I will need to improve the patch description and comments in
> v2.
It looks like drivers/net/dsa/b53 does not support this particular
switch. You could consider extending the driver. See
Documentation/devicetree/bindings/net/dsa/brcm,b53.yaml
for documentation of the binding.
Andrew
