On Sat, Sep 14, 2019 at 3:49 AM Russell King - ARM Linux admin <li...@armlinux.org.uk> wrote: > > On Fri, Sep 13, 2019 at 08:31:18PM -0700, Florian Fainelli wrote: > > +Russell, Andrew, Heiner, > > > > On 9/13/2019 9:44 AM, George McCollister wrote: > > > Every example of phylink SFP support I've seen is using an Ethernet > > > MAC with native SGMII. > > > Can phylink facilitate support of Fiber and Copper SFP modules > > > connected to an RGMII MAC if all of the following are true? > > > > I don't think that use case has been presented before, but phylink > > sounds like the tool that should help solve it. From your description > > below, it sounds like all the pieces are there to support it. Is the > > Ethernet MAC driver upstream? > > It has been presented, and it's something I've been trying to support > for the last couple of years - in fact, I have patches in my tree that > support a very similar scenario on the Macchiatobin with the 88x3310 > PHYs. > > > > 1) The MAC is connected via RGMII to a transceiver/PHY (such as > > > Marvell 88E1512) which then connects to the SFP via SERDER/SGMII. If > > > you want to see a block diagram it's the first one here: > > > https://www.marvell.com/transceivers/assets/Alaska_88E1512-001_product_brief.pdf > > As mentioned above, this is no different from the Macchiatobin, > where we have: > > .-------- RJ45 > MAC ---- 88x3310 PHY > `-------- SFP+ > > except instead of the MAC to PHY link being 10GBASE-R, it's RGMII, > and the PHY to SFP+ link is 10GBASE-R instead of 1000BASE-X. > > Note that you're abusing the term "SGMII". SGMII is a Cisco > modification of the IEEE 802.3 1000BASE-X protocol. Fiber SFPs > exclusively use 1000BASE-X protocol. However, some copper SFPs > (with a RJ45) do use SGMII. > > > > 2) The 1G Ethernet driver has been converted to use phylink. > > This is not necessary for this scenario. The PHY driver needs to > be updated to know about SFP though.
Excellent, this is exactly the information I was looking for. I had started converting the Ethernet driver to phylink but there was still a lot of work to do and I fear there was a significant potential for regressions. I'll abandon that and see if I can get it to work by making similar changes to the 1G Marvell PHY driver. I'm assuming I must set the sfp property of the PHY in DT instead of the MAC. > > See: > > http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=phy&id=ece56785ee0e9df40dc823fdc39ee74b4a7cd1c4 > > as an example of the 88x3310 supporting a SFP+ cage. This patch is > also necessary: > > http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=phy&id=ef2d699397ca28c7f89e01cc9e5037989096a990 Perfect. > > and if anything is going to stand in the way of progress on this, it > is likely to be that patch. I'll be attempting to post these after > the next merge window (i.o.w. probably posting them in three weeks > time.) Please CC me on these patches as I'll follow your lead for what I do on the 1G Marvell PHY driver. If you don't remember, that's fine, I understand. > > -- > RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ > FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up > According to speedtest.net: 11.9Mbps down 500kbps up Thanks, George
