[net-next,v5,01/15] Documentation: ACPI: DSD: Document MDIO PHY

Commit Message

Calvin Johnson Feb. 8, 2021, 3:12 p.m. UTC

Introduce ACPI mechanism to get PHYs registered on a MDIO bus and
provide them to be connected to MAC.

Describe properties "phy-handle" and "phy-mode".

Signed-off-by: Calvin Johnson <[e-mail]>
---

Changes in v5:
- More cleanup

Changes in v4:
- More cleanup

Changes in v3: None
Changes in v2:
- Updated with more description in document

 Documentation/firmware-guide/acpi/dsd/phy.rst | 133 ++++++++++++++++++
 1 file changed, 133 insertions(+)
 create mode 100644 Documentation/firmware-guide/acpi/dsd/phy.rst

Comments

Randy Dunlap Feb. 8, 2021, 8:01 p.m. UTC | #1

Hi,
Just a couple of nits below:

On 2/8/21 7:12 AM, Calvin Johnson wrote:
> Introduce ACPI mechanism to get PHYs registered on a MDIO bus and
> provide them to be connected to MAC.
> 
> Describe properties "phy-handle" and "phy-mode".
> 
> Signed-off-by: Calvin Johnson <[e-mail]>
> ---

>  Documentation/firmware-guide/acpi/dsd/phy.rst | 133 ++++++++++++++++++
>  1 file changed, 133 insertions(+)
>  create mode 100644 Documentation/firmware-guide/acpi/dsd/phy.rst
> 
> diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
> new file mode 100644
> index 000000000000..e1e99cae5eb2
> --- /dev/null
> +++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
> @@ -0,0 +1,133 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +=========================
> +MDIO bus and PHYs in ACPI
> +=========================
> +
> +The PHYs on an MDIO bus [1] are probed and registered using
> +fwnode_mdiobus_register_phy().
> +
> +Later, for connecting these PHYs to MAC, the PHYs registered on the

                                    to a MAC,

> +MDIO bus have to be referenced.
> +
> +This document introduces two _DSD properties that are to be used
> +for connecting PHYs on the MDIO bus [3] to the MAC layer.
> +
> +These properties are defined in accordance with the "Device
> +Properties UUID For _DSD" [2] document and the
> +daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
> +Data Descriptors containing them.
> +
> +phy-handle
> +----------

...

> +
> +Later, during the MAC driver initialization, the registered PHY devices
> +have to be retrieved from the MDIO bus. For this, the MAC driver need

                                                                    needs

> +references to the previously registered PHYs which are provided
> +as device object references (e.g. \_SB.MDI0.PHY1).


thanks.

Calvin Johnson Feb. 9, 2021, 2:34 p.m. UTC | #2

On Mon, Feb 08, 2021 at 12:01:57PM -0800, Randy Dunlap wrote:
> Hi,
> Just a couple of nits below:
> 
> On 2/8/21 7:12 AM, Calvin Johnson wrote:
> > Introduce ACPI mechanism to get PHYs registered on a MDIO bus and
> > provide them to be connected to MAC.
> > 
> > Describe properties "phy-handle" and "phy-mode".
> > 
> > Signed-off-by: Calvin Johnson <[e-mail]>
> > ---
> 
> >  Documentation/firmware-guide/acpi/dsd/phy.rst | 133 ++++++++++++++++++
> >  1 file changed, 133 insertions(+)
> >  create mode 100644 Documentation/firmware-guide/acpi/dsd/phy.rst
> > 
> > diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
> > new file mode 100644
> > index 000000000000..e1e99cae5eb2
> > --- /dev/null
> > +++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
> > @@ -0,0 +1,133 @@
> > +.. SPDX-License-Identifier: GPL-2.0
> > +
> > +=========================
> > +MDIO bus and PHYs in ACPI
> > +=========================
> > +
> > +The PHYs on an MDIO bus [1] are probed and registered using
> > +fwnode_mdiobus_register_phy().
> > +
> > +Later, for connecting these PHYs to MAC, the PHYs registered on the
> 
>                                     to a MAC,
Each PHY is connected to a MAC. So I'll change it to "PHYs to their respective MACs".
> 
> > +MDIO bus have to be referenced.
> > +
> > +This document introduces two _DSD properties that are to be used
> > +for connecting PHYs on the MDIO bus [3] to the MAC layer.
> > +
> > +These properties are defined in accordance with the "Device
> > +Properties UUID For _DSD" [2] document and the
> > +daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
> > +Data Descriptors containing them.
> > +
> > +phy-handle
> > +----------
> 
> ...
> 
> > +
> > +Later, during the MAC driver initialization, the registered PHY devices
> > +have to be retrieved from the MDIO bus. For this, the MAC driver need
> 
>                                                                     needs
> 
> > +references to the previously registered PHYs which are provided
> > +as device object references (e.g. \_SB.MDI0.PHY1).
> 
> 
> thanks.
> -- 
> ~Randy
>

Patch

diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst
new file mode 100644
index 000000000000..e1e99cae5eb2
--- /dev/null
+++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
@@ -0,0 +1,133 @@ 
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+MDIO bus and PHYs in ACPI
+=========================
+
+The PHYs on an MDIO bus [1] are probed and registered using
+fwnode_mdiobus_register_phy().
+
+Later, for connecting these PHYs to MAC, the PHYs registered on the
+MDIO bus have to be referenced.
+
+This document introduces two _DSD properties that are to be used
+for connecting PHYs on the MDIO bus [3] to the MAC layer.
+
+These properties are defined in accordance with the "Device
+Properties UUID For _DSD" [2] document and the
+daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
+Data Descriptors containing them.
+
+phy-handle
+----------
+For each MAC node, a device property "phy-handle" is used to reference
+the PHY that is registered on an MDIO bus. This is mandatory for
+network interfaces that have PHYs connected to MAC via MDIO bus.
+
+During the MDIO bus driver initialization, PHYs on this bus are probed
+using the _ADR object as shown below and are registered on the MDIO bus.
+
+::
+      Scope(\_SB.MDI0)
+      {
+        Device(PHY1) {
+          Name (_ADR, 0x1)
+        } // end of PHY1
+
+        Device(PHY2) {
+          Name (_ADR, 0x2)
+        } // end of PHY2
+      }
+
+Later, during the MAC driver initialization, the registered PHY devices
+have to be retrieved from the MDIO bus. For this, the MAC driver need
+references to the previously registered PHYs which are provided
+as device object references (e.g. \_SB.MDI0.PHY1).
+
+phy-mode
+--------
+The "phy-mode" _DSD property is used to describe the connection to
+the PHY. The valid values for "phy-mode" are defined in [4].
+
+The following ASL example illustrates the usage of these properties.
+
+DSDT entry for MDIO node
+------------------------
+
+The MDIO bus has an SoC component (MDIO controller) and a platform
+component (PHYs on the MDIO bus).
+
+a) Silicon Component
+This node describes the MDIO controller, MDI0
+---------------------------------------------
+::
+	Scope(_SB)
+	{
+	  Device(MDI0) {
+	    Name(_HID, "NXP0006")
+	    Name(_CCA, 1)
+	    Name(_UID, 0)
+	    Name(_CRS, ResourceTemplate() {
+	      Memory32Fixed(ReadWrite, MDI0_BASE, MDI_LEN)
+	      Interrupt(ResourceConsumer, Level, ActiveHigh, Shared)
+	       {
+		 MDI0_IT
+	       }
+	    }) // end of _CRS for MDI0
+	  } // end of MDI0
+	}
+
+b) Platform Component
+The PHY1 and PHY2 nodes represent the PHYs connected to MDIO bus MDI0
+---------------------------------------------------------------------
+::
+	Scope(\_SB.MDI0)
+	{
+	  Device(PHY1) {
+	    Name (_ADR, 0x1)
+	  } // end of PHY1
+
+	  Device(PHY2) {
+	    Name (_ADR, 0x2)
+	  } // end of PHY2
+	}
+
+DSDT entries representing MAC nodes
+-----------------------------------
+
+Below are the MAC nodes where PHY nodes are referenced.
+phy-mode and phy-handle are used as explained earlier.
+------------------------------------------------------
+::
+	Scope(\_SB.MCE0.PR17)
+	{
+	  Name (_DSD, Package () {
+	     ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		 Package () {
+		     Package (2) {"phy-mode", "rgmii-id"},
+		     Package (2) {"phy-handle", \_SB.MDI0.PHY1}
+	      }
+	   })
+	}
+
+	Scope(\_SB.MCE0.PR18)
+	{
+	  Name (_DSD, Package () {
+	    ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+		Package () {
+		    Package (2) {"phy-mode", "rgmii-id"},
+		    Package (2) {"phy-handle", \_SB.MDI0.PHY2}}
+	    }
+	  })
+	}
+
+References
+==========
+
+[1] Documentation/networking/phy.rst
+
+[2] https://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf
+
+[3] Documentation/firmware-guide/acpi/DSD-properties-rules.rst
+
+[4] Documentation/devicetree/bindings/net/ethernet-controller.yaml