[PATCH RFC] powerpc: switch two fixed phy links to full duplex

[PATCH RFC] powerpc: switch two fixed phy links to full duplex

[Heiner Kallweit]

These two fixed links are the only ones in-kernel specifying half duplex.
If these could be switched to full duplex, then half duplex handling
could be removed from phylib fixed phy, phylink, swphy.

The SoC MAC's are capable of full duplex, fs_enet MAC driver is as well.
Anything that would keep us from switching to full duplex?

Whilst at it, replace the deprecated old fixed-link binding.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
 arch/powerpc/boot/dts/mgcoge.dts | 6 +++++-
 arch/powerpc/boot/dts/tqm8xx.dts | 6 +++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/dts/mgcoge.dts b/arch/powerpc/boot/dts/mgcoge.dts
index 9cefed20723..cea9bdc65dc 100644
--- a/arch/powerpc/boot/dts/mgcoge.dts
+++ b/arch/powerpc/boot/dts/mgcoge.dts
@@ -153,7 +153,11 @@ eth0: ethernet@11a60 {
 				interrupt-parent = <&PIC>;
 				linux,network-index = <0>;
 				fsl,cpm-command = <0xce00000>;
-				fixed-link = <0 0 10 0 0>;
+
+				fixed-link {
+					speed = <10>;
+					full-duplex;
+				};
 			};
 
 			i2c@11860 {
diff --git a/arch/powerpc/boot/dts/tqm8xx.dts b/arch/powerpc/boot/dts/tqm8xx.dts
index d16cdfd8120..e582487d5a3 100644
--- a/arch/powerpc/boot/dts/tqm8xx.dts
+++ b/arch/powerpc/boot/dts/tqm8xx.dts
@@ -185,7 +185,11 @@ eth0: ethernet@a00 {
 				interrupt-parent = <&CPM_PIC>;
 				fsl,cpm-command = <0000>;
 				linux,network-index = <0>;
-				fixed-link = <0 0 10 0 0>;
+
+				fixed-link {
+					speed = <10>;
+					full-duplex;
+				};
 			};
 		};
 	};
-- 
2.52.0

Re: [PATCH RFC] powerpc: switch two fixed phy links to full duplex

[Andrew Lunn]

On Fri, Dec 05, 2025 at 06:21:50PM +0100, Heiner Kallweit wrote:
> These two fixed links are the only ones in-kernel specifying half duplex.
> If these could be switched to full duplex, then half duplex handling
> could be removed from phylib fixed phy, phylink, swphy.
> 
> The SoC MAC's are capable of full duplex, fs_enet MAC driver is as well.
> Anything that would keep us from switching to full duplex?

What do we know about the device on the other end of the link? Maybe
that is what is limiting it to 10Half?

	Andrew

Re: [PATCH RFC] powerpc: switch two fixed phy links to full duplex

[Heiner Kallweit]

On 12/5/2025 6:50 PM, Andrew Lunn wrote:
> On Fri, Dec 05, 2025 at 06:21:50PM +0100, Heiner Kallweit wrote:
>> These two fixed links are the only ones in-kernel specifying half duplex.
>> If these could be switched to full duplex, then half duplex handling
>> could be removed from phylib fixed phy, phylink, swphy.
>>
>> The SoC MAC's are capable of full duplex, fs_enet MAC driver is as well.
>> Anything that would keep us from switching to full duplex?
> 
> What do we know about the device on the other end of the link? Maybe
> that is what is limiting it to 10Half?
> 
I found no hint that anything is connected to this ethernet port on
the two boards. Hard to find any information because the boards are
>15yrs old. Seems this are dummy entries, just to let fs_enet load.

> 	Andrew

Heiner