[PATCH devicetree] arm64: dts: ls1028a: mark internal links between Felix and ENETC as capable of flow control

[PATCH devicetree] arm64: dts: ls1028a: mark internal links between Felix and ENETC as capable of flow control

[Vladimir Oltean]

The internal Ethernet switch suffers from erratum A-050484 ("Ethernet
flow control not functional on L2 switch NPI port when XFH is used").
XFH stands for "Extraction Frame Header" - which basically means the
default "ocelot" DSA tagging protocol.

However, the switch supports one other tagging protocol - "ocelot-8021q",
and this is not subject to the erratum above. So describe the hardware
ability to pass PAUSE frames in the device tree, and let the driver
figure out whether it should use flow control on the CPU port or not,
depending on whether the "ocelot" or "ocelot-8021q" tagging protocol is
being used.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
index 343ecf0e8973..71e5cdd931ee 100644
--- a/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
+++ b/arch/arm64/boot/dts/freescale/fsl-ls1028a.dtsi
@@ -1025,6 +1025,7 @@ enetc_port2: ethernet@0,2 {
 				fixed-link {
 					speed = <2500>;
 					full-duplex;
+					pause;
 				};
 			};
 
@@ -1083,6 +1084,7 @@ mscc_felix_port4: port@4 {
 						fixed-link {
 							speed = <2500>;
 							full-duplex;
+							pause;
 						};
 					};
 
@@ -1094,6 +1096,7 @@ mscc_felix_port5: port@5 {
 						fixed-link {
 							speed = <1000>;
 							full-duplex;
+							pause;
 						};
 					};
 				};
@@ -1108,6 +1111,7 @@ enetc_port3: ethernet@0,6 {
 				fixed-link {
 					speed = <1000>;
 					full-duplex;
+					pause;
 				};
 			};
 
-- 
2.25.1

Re: [PATCH devicetree] arm64: dts: ls1028a: mark internal links between Felix and ENETC as capable of flow control

[Shawn Guo]

On Wed, Sep 29, 2021 at 02:52:26PM +0300, Vladimir Oltean wrote:
> The internal Ethernet switch suffers from erratum A-050484 ("Ethernet
> flow control not functional on L2 switch NPI port when XFH is used").
> XFH stands for "Extraction Frame Header" - which basically means the
> default "ocelot" DSA tagging protocol.
> 
> However, the switch supports one other tagging protocol - "ocelot-8021q",
> and this is not subject to the erratum above. So describe the hardware
> ability to pass PAUSE frames in the device tree, and let the driver
> figure out whether it should use flow control on the CPU port or not,
> depending on whether the "ocelot" or "ocelot-8021q" tagging protocol is
> being used.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Applied, thanks!