[PATCH net-next v3 4/4] dt-bindings: net: freescale: enetc: Add connection bindings for ENETC ethernet nodes

[Claudiu Manoil <claudiu.manoil@nxp.com>]

Define connection bindings (external PHY connections and internal links)
for the ENETC on-chip ethernet controllers.

Signed-off-by: Claudiu Manoil <claudiu.manoil@nxp.com>
---
v3 - added this patch to the set

 .../devicetree/bindings/net/fsl-enetc.txt          | 109 +++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/fsl-enetc.txt

diff --git a/Documentation/devicetree/bindings/net/fsl-enetc.txt b/Documentation/devicetree/bindings/net/fsl-enetc.txt
new file mode 100644
index 0000000..2fbb998
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/fsl-enetc.txt
@@ -0,0 +1,109 @@
+* ENETC ethernet nodes - external connection bindings
+
+The ENETC ethernet controllers are PCIe integrated endpoints
+(IEPs), on-chip devices discoverable as standard PCIe endpoints,
+integrated into Freescale SoCs.  The ENETC devices are self
+contained, the information needed for device initialization
+is available in hardware (PCIe ECAM area).  However, depending
+on board design, their external connections are configurable.
+As usual for SoCs, device tree nodes may be used to define these
+external connections.  The rest of the document specifies how
+external connections for ENETC ethernet controllers may be
+defined via device tree nodes.
+
+Silicon (SoC) availability (<SoC name>: <SoC DT path/name>)
+	- LS1028A: [arch/arm64]	[...]freescale/fsl-ls1028a.dtsi
+
+
+* ENETC nodes
+
+Defined in the SoC device tree as "pci" child nodes of the
+"pci-host-ecam-generic" compatible "pcie" parent node also known
+as the Integrated Endpoint Root Complex (IERC) SoC node.
+
+Structure - example (LS1028A):
+
+	pcie@1f0000000 {
+		compatible = "pci-host-ecam-generic";
+		device_type = "pci";
+		...
+		enetc_port0: pci@0,0 {
+			reg = <0x000000 0 0 0 0>;
+		};
+		enetc_port1: pci@0,1 {
+			reg = <0x000100 0 0 0 0>;
+		};
+		...
+	}
+
+Each ENETC node has a device number and a function number (expressed
+by its "reg" property and pci node name, i.e. "pci@0,1" represents
+device number 0 and functions number 1).  Only the standard pci "reg"
+property is needed here.
+For easy reference, each ENETC node is tagged by a handle having the
+following format:
+
+	"enetc_port<idx>"   where, idx = 0 .. n-1;
+			    n - #of available ENETC nodes (Ports) on
+				the given SoC.
+
+NOTES
+i. The SoC H/W Reference Manual provides a mapping of the ENETC Port
+numbers to the PCIe Device Number/ Function Number.
+Example (LS1028):
+	All ENETC PFs (PCIe Physical Functions) have Device Number 0.
+	Port 0 - PF0 (pci@0,0)
+	Port 1 - PF1 (pci@0,1)
+	Port 2 - PF2 (pci@0,2)
+	Port 3 - PF6 (pci@0,6)
+
+ii. The SoC H/W Reference Manual also defines which ENETC Ports may have
+external connections (external ports) and which ones are internally
+connected to a on-chip L2 switch for instance (internal ports).
+
+
+* Defining connections for ENETC nodes
+
+To define external connections for the external ENETC Ports on a given
+board/platform, the board device tree should include the SoC device tree
+and reference the external ports by their "enetc_port<idx>" handle.
+
+Following cases arise, defining all possible connection bindings:
+
+1) The ENETC Port is connected to a MDIO configurable PHY:
+
+	In this case, the ENETC node should include a "mdio" sub-node
+	that in turn should contain the "phy" node describing the
+	external phy.  ENETC Port node structure (example):
+
+	&enetc_port0 {
+		phy-handle = <&sgmii_phy0>;
+		phy-connection-type = "sgmii";
+
+		mdio {
+			#address-cells = <1>;
+			#size-cells = <0>;
+			sgmii_phy0: ethernet-phy@2 {
+				reg = <0x2>;
+			};
+		};
+	};
+
+	All properties are mandatory for this case, their bindings already
+	defined (see ethernet.txt and phy.txt).
+
+2) The ENETC Port has a fixed-link connection:
+
+	In this case, the ENETC Port node defines a fixed link connection,
+	with the following structure (example):
+
+	&enetc_port2 {
+		fixed-link {
+			speed = <1000>;
+			full-duplex;
+		};
+	};
+
+	The "fixed-link" node properties are standard (as defined in
+	fixed-link.txt).
+	This connection type also applies to the internal ENETC Ports.
-- 
2.7.4