Messages in this thread | | | Subject | Re: [PATCH net-next 02/28] dt-bindings: net: fman: Add additional interface properties | From | Sean Anderson <> | Date | Sat, 18 Jun 2022 11:55:38 -0400 |
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Hi Krzysztof,
On 6/17/22 9:16 PM, Krzysztof Kozlowski wrote: > On 17/06/2022 13:32, Sean Anderson wrote: >> At the moment, MEMACs are configured almost completely based on the >> phy-connection-type. That is, if the phy interface is RGMII, it assumed >> that RGMII is supported. For some interfaces, it is assumed that the >> RCW/bootloader has set up the SerDes properly. The actual link state is >> never reported. >> >> To address these shortcomings, the driver will need additional >> information. First, it needs to know how to access the PCS/PMAs (in >> order to configure them and get the link status). The SGMII PCS/PMA is >> the only currently-described PCS/PMA. Add the XFI and QSGMII PCS/PMAs as >> well. The XFI (and 1GBase-KR) PCS/PMA is a c45 "phy" which sits on the >> same MDIO bus as SGMII PCS/PMA. By default they will have conflicting >> addresses, but they are also not enabled at the same time by default. >> Therefore, we can let the default address for the XFI PCS/PMA be the >> same as for SGMII. This will allow for backwards-compatibility. >> >> QSGMII, however, cannot work with the current binding. This is because >> the QSGMII PCS/PMAs are only present on one MAC's MDIO bus. At the >> moment this is worked around by having every MAC write to the PCS/PMA >> addresses (without checking if they are present). This only works if >> each MAC has the same configuration, and only if we don't need to know >> the status. Because the QSGMII PCS/PMA will typically be located on a >> different MDIO bus than the MAC's SGMII PCS/PMA, there is no fallback >> for the QSGMII PCS/PMA. >> >> MEMACs (across all SoCs) support the following protocols: >> >> - MII >> - RGMII >> - SGMII, 1000Base-X, and 1000Base-KX >> - 2500Base-X (aka 2.5G SGMII) >> - QSGMII >> - 10GBase-R (aka XFI) and 10GBase-KR >> - XAUI and HiGig >> >> Each line documents a set of orthogonal protocols (e.g. XAUI is >> supported if and only if HiGig is supported). Additionally, >> >> - XAUI implies support for 10GBase-R >> - 10GBase-R is supported if and only if RGMII is not supported >> - 2500Base-X implies support for 1000Base-X >> - MII implies support for RGMII >> >> To switch between different protocols, we must reconfigure the SerDes. >> This is done by using the standard phys property. We can also use it to >> validate whether different protocols are supported (e.g. using >> phy_validate). This will work for serial protocols, but not RGMII or >> MII. Additionally, we still need to be compatible when there is no >> SerDes. >> >> While we can detect 10G support by examining the port speed (as set by >> fsl,fman-10g-port), we cannot determine support for any of the other >> protocols based on the existing binding. In fact, the binding works >> against us in some respects, because pcsphy-handle is required even if >> there is no possible PCS/PMA for that MAC. To allow for backwards- >> compatibility, we use a boolean-style property for RGMII (instead of >> presence/absence-style). When the property for RGMII is missing, we will >> assume that it is supported. The exception is MII, since no existing >> device trees use it (as far as I could tell). >> >> Unfortunately, QSGMII support will be broken for old device trees. There >> is nothing we can do about this because of the PCS/PMA situation (as >> described above). >> >> Signed-off-by: Sean Anderson <sean.anderson@seco.com> > > Thanks for the patch but you add too many new properties. The file > should be converted to YAML/DT schema first.
Perhaps. However, conversion to yaml is a non-trivial task, especially for a complicated binding such as this one. I am more than happy to rework this patch to be based on a yaml conversion, but I do not have the bandwidth to do so myself.
If you have any comments on the binding changes themselves, that would be much appreciated.
--Sean
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