On Fri, Jan 22, 2021 at 4:43 PM Calvin Johnson
<calvin.johnson@xxxxxxxxxxx> 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 <calvin.johnson@xxxxxxxxxxx>
> ---
>
> Changes in v4:
> - More cleanup
This looks much better that the previous versions IMV, some nits below.
> Changes in v3: None
> Changes in v2:
> - Updated with more description in document
>
> Documentation/firmware-guide/acpi/dsd/phy.rst | 129 ++++++++++++++++++
> 1 file changed, 129 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..76fca994bc99
> --- /dev/null
> +++ b/Documentation/firmware-guide/acpi/dsd/phy.rst
> @@ -0,0 +1,129 @@
> +.. 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().
Empty line here, please.
> +Later, for connecting these PHYs to MAC, the PHYs registered on the
> +MDIO bus have to be referenced.
> +
> +The UUID given below should be used as mentioned in the "Device Properties
> +UUID For _DSD" [2] document.
> + - UUID: daffd814-6eba-4d8c-8a91-bc9bbf4aa301
I would drop the above paragraph.
> +
> +This document introduces two _DSD properties that are to be used
> +for PHYs on the MDIO bus.[3]
I'd say "for connecting PHYs on the MDIO bus [3] to the MAC layer."
above and add the following here:
"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.
Do you want to mention the "reg" property here? I think it would be
useful to do that.
> +
> +::
> + 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, MAC driver needs
"the MAC driver" I suppose?
> +reference to the previously registered PHYs which are provided
s/reference/references/ (plural)
> +using reference to the device as {\_SB.MDI0.PHY1}.
"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].
> +
One empty line should be sufficient.
> +
> +An ASL example of this is shown below.
"The following ASL example illustrates the usage of these properties."
> +
> +DSDT entry for MDIO node
> +------------------------
Empty line here, please.
> +The MDIO bus has an SoC component(MDIO controller) and a platform
Missing space after "component".
> +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
> +This node defines the PHYs that are connected to the MDIO bus, MDI0
"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
-----------------------------------"
Plus an empty line.
> +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
> --
> 2.17.1
>
