[PATCH v2 1/2] dt-bindings: net: xilinx_axienet: add pcs-handle attribute

[PATCH v2 1/2] dt-bindings: net: xilinx_axienet: add pcs-handle attribute

[Andy Chiu]

Document the new pcs-handle attribute to support connecting to an
external PHY in SGMII or 1000Base-X modes through the internal PCS/PMA
PHY.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
---
 Documentation/devicetree/bindings/net/xilinx_axienet.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/net/xilinx_axienet.txt b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
index b8e4894bc634..2a9a3a90eb63 100644
--- a/Documentation/devicetree/bindings/net/xilinx_axienet.txt
+++ b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
@@ -68,6 +68,11 @@ Optional properties:
 		  required through the core's MDIO interface (i.e. always,
 		  unless the PHY is accessed through a different bus).
 
+ - pcs-handle: 	  Phandle to the internal PCS/PMA PHY, if a fixed external PHY
+		  is tied to it in SGMII or 1000Base-X modes. This is not
+		  required for SFP connection. The driver would use phy-handle
+		  to reference the PCS/PMA PHY in such case.
+
 Example:
 	axi_ethernet_eth: ethernet@40c00000 {
 		compatible = "xlnx,axi-ethernet-1.00.a";
-- 
2.34.1

[PATCH v2 2/2] net: axiemac: use a phandle to reference pcs_phy

[Andy Chiu]

In some SGMII use cases where both an external PHY and the internal
PCS/PMA PHY need to be configured, we should explicitly use a phandle
"pcs-phy" to get the reference to the PCS/PMA PHY. Otherwise, the driver
would use "phy-handle" in the DT as the reference to both external and
the internal PCS/PMA PHY.

In other cases where the core is connected to a SFP cage, we could
fallback, pointing phy-handle to the intenal PCS/PMA PHY, and let the
driver connect to the SFP module, if exist, via phylink.

Fixes: 1a02556086fc (net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode)
Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
---
 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 6fd5157f0a6d..17de81cc0ca5 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2078,7 +2078,13 @@ static int axienet_probe(struct platform_device *pdev)
 			ret = -EINVAL;
 			goto cleanup_mdio;
 		}
-		lp->pcs_phy = of_mdio_find_device(lp->phy_node);
+		np = of_parse_phandle(pdev->dev.of_node, "pcs-handle", 0);
+		if (np) {
+			lp->pcs_phy = of_mdio_find_device(np);
+			of_node_put(np);
+		} else {
+			lp->pcs_phy = of_mdio_find_device(lp->phy_node);
+		}
 		if (!lp->pcs_phy) {
 			ret = -EPROBE_DEFER;
 			goto cleanup_mdio;
-- 
2.34.1

Re: [PATCH v2 2/2] net: axiemac: use a phandle to reference pcs_phy

[Andy Chiu]

loop in: radhey.shyam.pandey@xilinx.com

I am sending this out since I forgot to CC the maintainer of the
driver, again...

Sorry for being noisy here.

Regards,
Andy


On Thu, Mar 17, 2022 at 5:21 PM Andy Chiu <andy.chiu@sifive.com> wrote:
>
> In some SGMII use cases where both an external PHY and the internal
> PCS/PMA PHY need to be configured, we should explicitly use a phandle
> "pcs-phy" to get the reference to the PCS/PMA PHY. Otherwise, the driver
> would use "phy-handle" in the DT as the reference to both external and
> the internal PCS/PMA PHY.
>
> In other cases where the core is connected to a SFP cage, we could
> fallback, pointing phy-handle to the intenal PCS/PMA PHY, and let the
> driver connect to the SFP module, if exist, via phylink.
>
> Fixes: 1a02556086fc (net: axienet: Properly handle PCS/PMA PHY for 1000BaseX mode)
> Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
> Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
> ---
>  drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 6fd5157f0a6d..17de81cc0ca5 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -2078,7 +2078,13 @@ static int axienet_probe(struct platform_device *pdev)
>                         ret = -EINVAL;
>                         goto cleanup_mdio;
>                 }
> -               lp->pcs_phy = of_mdio_find_device(lp->phy_node);
> +               np = of_parse_phandle(pdev->dev.of_node, "pcs-handle", 0);
> +               if (np) {
> +                       lp->pcs_phy = of_mdio_find_device(np);
> +                       of_node_put(np);
> +               } else {
> +                       lp->pcs_phy = of_mdio_find_device(lp->phy_node);
> +               }
>                 if (!lp->pcs_phy) {
>                         ret = -EPROBE_DEFER;
>                         goto cleanup_mdio;
> --
> 2.34.1
>

Re: [PATCH v2 1/2] dt-bindings: net: xilinx_axienet: add pcs-handle attribute

[Andy Chiu]

loop in: radhey.shyam.pandey@xilinx.com


On Thu, Mar 17, 2022 at 5:21 PM Andy Chiu <andy.chiu@sifive.com> wrote:
>
> Document the new pcs-handle attribute to support connecting to an
> external PHY in SGMII or 1000Base-X modes through the internal PCS/PMA
> PHY.
>
> Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
> Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
> ---
>  Documentation/devicetree/bindings/net/xilinx_axienet.txt | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/net/xilinx_axienet.txt b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> index b8e4894bc634..2a9a3a90eb63 100644
> --- a/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> +++ b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> @@ -68,6 +68,11 @@ Optional properties:
>                   required through the core's MDIO interface (i.e. always,
>                   unless the PHY is accessed through a different bus).
>
> + - pcs-handle:           Phandle to the internal PCS/PMA PHY, if a fixed external PHY
> +                 is tied to it in SGMII or 1000Base-X modes. This is not
> +                 required for SFP connection. The driver would use phy-handle
> +                 to reference the PCS/PMA PHY in such case.
> +
>  Example:
>         axi_ethernet_eth: ethernet@40c00000 {
>                 compatible = "xlnx,axi-ethernet-1.00.a";
> --
> 2.34.1
>

Re: [PATCH v2 1/2] dt-bindings: net: xilinx_axienet: add pcs-handle attribute

[Robert Hancock]

On Thu, 2022-03-17 at 18:02 +0800, Andy Chiu wrote:
> loop in: radhey.shyam.pandey@xilinx.com
> 
> 
> On Thu, Mar 17, 2022 at 5:21 PM Andy Chiu <andy.chiu@sifive.com> wrote:
> > Document the new pcs-handle attribute to support connecting to an
> > external PHY in SGMII or 1000Base-X modes through the internal PCS/PMA
> > PHY.
> > 
> > Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
> > Reviewed-by: Greentime Hu <greentime.hu@sifive.com>
> > ---
> >  Documentation/devicetree/bindings/net/xilinx_axienet.txt | 5 +++++
> >  1 file changed, 5 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> > b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> > index b8e4894bc634..2a9a3a90eb63 100644
> > --- a/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> > +++ b/Documentation/devicetree/bindings/net/xilinx_axienet.txt
> > @@ -68,6 +68,11 @@ Optional properties:
> >                   required through the core's MDIO interface (i.e. always,
> >                   unless the PHY is accessed through a different bus).
> > 
> > + - pcs-handle:           Phandle to the internal PCS/PMA PHY, if a fixed
> > external PHY
> > +                 is tied to it in SGMII or 1000Base-X modes. This is not
> > +                 required for SFP connection. The driver would use phy-
> > handle
> > +                 to reference the PCS/PMA PHY in such case.
> > +

I would say pcs-handle should be preferably used to point to the PCS/PMA in all
cases. phy-handle should be used for a fixed PHY downstream of the PCS/PMA if
one exists - using that for the PCS/PMA would be just for backward
compatibility with old device trees.

Might want a comment as such in the code as well, where it is retrieving phy-
handle for the PCS and pcs-handle is not present.

> >  Example:
> >         axi_ethernet_eth: ethernet@40c00000 {
> >                 compatible = "xlnx,axi-ethernet-1.00.a";
> > --
> > 2.34.1
> > 
-- 
Robert Hancock
Senior Hardware Designer, Calian Advanced Technologies
www.calian.com

Re: [PATCH v2 1/2] dt-bindings: net: xilinx_axienet: add pcs-handle attribute

[Andy Chiu]

Thanks for the explanation,

I will include that on the v3 patchset.

Andy