| Message ID | 20210621173028.3541424-2-mw@semihalf.com |
|---|---|
| State | New |
| Headers | show |
| Series | ACPI MDIO support for Marvell controllers | expand |
> +MAC node example with a "fixed-link" subnode. > +--------------------------------------------- > + > +.. code-block:: none > + > + Scope(\_SB.PP21.ETH1) > + { > + Name (_DSD, Package () { > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > + Package () { > + Package () {"phy-mode", "sgmii"}, > + }, > + ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), > + Package () { > + Package () {"fixed-link", "LNK0"} > + } > + }) At least in the DT world, it is pretty unusual to see both fixed-link and phy-mode. You might have one of the four RGMII modes, in order to set the delays when connecting to a switch. But sgmii and fixed link seems very unlikely, how is sgmii autoneg going to work? > + Name (LNK0, Package(){ // Data-only subnode of port > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > + Package () { > + Package () {"speed", 1000}, > + Package () {"full-duplex", 1} > + } > + }) > + } > + Andrew
Hi Andrew, śr., 23 cze 2021 o 22:18 Andrew Lunn <andrew@lunn.ch> napisał(a): > > > +MAC node example with a "fixed-link" subnode. > > +--------------------------------------------- > > + > > +.. code-block:: none > > + > > + Scope(\_SB.PP21.ETH1) > > + { > > + Name (_DSD, Package () { > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () {"phy-mode", "sgmii"}, > > + }, > > + ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), > > + Package () { > > + Package () {"fixed-link", "LNK0"} > > + } > > + }) > > At least in the DT world, it is pretty unusual to see both fixed-link > and phy-mode. I did a quick experiment: git grep -C 8 fixed-link arch/arm64/boot/dts/ git grep -C 8 fixed-link arch/arm/boot/dts/ almost all MAC nodes (i.e. not switch ports) containing 'fixed-link' have an adjacent 'phy-mode' property defined. How else would the drivers know how to configure the HW connection type in its registers? > You might have one of the four RGMII modes, in order to > set the delays when connecting to a switch. But sgmii and fixed link > seems very unlikely, how is sgmii autoneg going to work? > Indeed most cases in the tree are "rgmii*", but we can also see e.g. 10gbase-r, sgmii and 2500base-x. You can find sgmii + fixed-link on the eth1 of the armada-388-clearfog. Regarding the autoneg - I'm mostly familiar with the mvneta/mvpp2, but in this mode the autonegotiation is disabled and the link is forcibly set up/down in MAC registers during the netedev_open/close accordingly. FYI, along with the 10G ports on CN913x-DB, I tested fixed-link on Macchiatobin sgmii port. Anyway - all above is a bit side discussion to the actual DSDT description and how the fixed-link subnode looks like. I think phy-mode set to "sgmii" is not incorrect, but we can change it to whatever other type of your preference, as well. Best regards, Marcin > > + Name (LNK0, Package(){ // Data-only subnode of port > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () {"speed", 1000}, > > + Package () {"full-duplex", 1} > > + } > > + }) > > + } > > + > > Andrew
> Anyway - all above is a bit side discussion to the actual DSDT > description and how the fixed-link subnode looks like. I think > phy-mode set to "sgmii" is not incorrect, but we can change it to > whatever other type of your preference, as well. rgmii would be better, so we side step the whole auto-neg discussion. Andrew
Hi Andrew, On Wed, Jun 23, 2021 at 10:18:02PM +0200, Andrew Lunn wrote: > > +MAC node example with a "fixed-link" subnode. > > +--------------------------------------------- > > + > > +.. code-block:: none > > + > > + Scope(\_SB.PP21.ETH1) > > + { > > + Name (_DSD, Package () { > > + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), > > + Package () { > > + Package () {"phy-mode", "sgmii"}, > > + }, > > + ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), > > + Package () { > > + Package () {"fixed-link", "LNK0"} > > + } > > + }) > > At least in the DT world, it is pretty unusual to see both fixed-link > and phy-mode. You might have one of the four RGMII modes, in order to > set the delays when connecting to a switch. But sgmii and fixed link > seems very unlikely, how is sgmii autoneg going to work? SGMII autoneg is supposed to be disabled if you have a fixed-link, and there is nothing unusual in that kind of setup. There are 3 types of phylink setups: MLO_AN_INBAND: there might or might not be a phy-handle, but SGMII autoneg should be enabled and the MAC should be reconfigured automatically (in hardware) to the right speed/duplex based on that MLO_AN_PHY: there is a phy-handle but SGMII autoneg should be disabled* and the MAC should be reconfigured (forced) in software to the speed/duplex determined by reading the PHY MDIO registers MLO_AN_FIXED: there is no phy-handle or phy_device, but the driver should do the same thing, the speed/duplex is configured by management (in this case DT/ACPI) *there appears to be some debate here, since the "managed" property is phylink-specific and therefore a phylib driver will not necessarily disable its in-band autoneg, but this is what the existing phylink_pcs drivers in drivers/net/pcs/ do and I think there's nothing wrong with settling on that if phylink is being used. It does create some interesting questions though when a driver is being converted from phylib to phylink, since the meaning of the existing firmware bindings suddenly changes. An SGMII link with MLO_AN_FIXED is nothing unusual, it is in fact very widespread as a way to reduce pin count compared to the parallel RGMII. I suspect there are more DSA setups in the field with an SGMII fixed-link than with RGMII fixed-link, due to practicality. The 2 characteristic features of SGMII compared to 1000base-X are: - customization of the 16-bit configuration word communicated via the clause 37 state machines. Those are bypassed in MLO_AN_PHY and MLO_AN_FIXED modes, true - symbol replication at 10/100 speeds. So since it is equally valid to have an SGMII fixed-link at 100Mbps or 10Mbps, it is just as valid to have an SGMII fixed-link at 1Gbps with in-band autoneg disabled.
diff --git a/Documentation/firmware-guide/acpi/dsd/phy.rst b/Documentation/firmware-guide/acpi/dsd/phy.rst index 0d49bad2ea9c..680ad179e5f9 100644 --- a/Documentation/firmware-guide/acpi/dsd/phy.rst +++ b/Documentation/firmware-guide/acpi/dsd/phy.rst @@ -50,6 +50,21 @@ 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]. +managed +------- +Optional property, which specifies the PHY management type. +The valid values for "managed" are defined in [4]. + +fixed-link +---------- +The "fixed-link" is described by a data-only subnode of the +MAC port, which is linked in the _DSD package via +hierarchical data extension (UUID dbb8e3e6-5886-4ba6-8795-1319f52a966b +in accordance with [5] "_DSD Implementation Guide" document). +The subnode should comprise a required property ("speed") and +possibly the optional ones - complete list of parameters and +their values are specified in [4]. + The following ASL example illustrates the usage of these properties. DSDT entry for MDIO node @@ -128,6 +143,48 @@ phy-mode and phy-handle are used as explained earlier. }) } +MAC node example where "managed" property is specified. +------------------------------------------------------- + +.. code-block:: none + + Scope(\_SB.PP21.ETH0) + { + Name (_DSD, Package () { + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), + Package () { + Package () {"phy-mode", "sgmii"}, + Package () {"managed", "in-band-status"} + } + }) + } + +MAC node example with a "fixed-link" subnode. +--------------------------------------------- + +.. code-block:: none + + Scope(\_SB.PP21.ETH1) + { + Name (_DSD, Package () { + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), + Package () { + Package () {"phy-mode", "sgmii"}, + }, + ToUUID("dbb8e3e6-5886-4ba6-8795-1319f52a966b"), + Package () { + Package () {"fixed-link", "LNK0"} + } + }) + Name (LNK0, Package(){ // Data-only subnode of port + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), + Package () { + Package () {"speed", 1000}, + Package () {"full-duplex", 1} + } + }) + } + References ========== @@ -138,3 +195,5 @@ References [3] Documentation/firmware-guide/acpi/DSD-properties-rules.rst [4] Documentation/devicetree/bindings/net/ethernet-controller.yaml + +[5] https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.pdf
Document additional MAC configuration modes which can be processed by the existing fwnode_ phylink helpers: * "managed" standard ACPI _DSD property [1] * "fixed-link" data-only subnode linked in the _DSD package via generic mechanism of the hierarchical data extension [2] [1] https://www.uefi.org/sites/default/files/resources/_DSD-device-properties-UUID.pdf [2] https://github.com/UEFI/DSD-Guide/blob/main/dsd-guide.pdf Signed-off-by: Marcin Wojtas <mw@semihalf.com> --- Documentation/firmware-guide/acpi/dsd/phy.rst | 59 ++++++++++++++++++++ 1 file changed, 59 insertions(+)