On 21 Mar 2018 at 11:47, Andrew Lunn , net...@vger.ker wrote: > Another question is, how to write the driver's initialization > sequence, for it to correctly decide if the SFP is SERDES or SGMII or > what. I could just follow the config obtained from the i210 EEPROM. > Alternatively, or somehow combined to that, I could try checking if > something responds to me over i2c, and do a quick check for SPD > EEPROM. If I find one, do a check for "MII regs over i2c" - at all > i2c slave addresses between 0x41..0x59 EXCEPT 0x50/0x51. > If I find MII-i2c regs, it's clear that the transceiver contains a > PHY, and wants to run in SGMII mode - otherwise it's a SERDES thing. > If nothing is found in i2c mode, and inherited i210 config indicates > SGMII, try external MDIO... if that fails, revert to SERDES. >
I was also wondering if someone has written any kernel-space support for the SFP's. Sure enough, I've found lots of code by Russell King under drivers/net/phy. I started reading from sfp.c, went on to sfp-bus.c, next the phylink stuff... Answers lots of my questions. Clearly someone has "been there and done that" - I mean how to interpret SFP EEPROM bits and act upon them in the PHY initialization. And I keep wondering where to start :-) If I grep phylink recursively in drivers/net/ethernet, I get no hits... Any chance of hooking this up to the igb driver in a clean way? There are notes in the phylib drivers that this is "platform" stuff - a keyword which speaks to me of stuff hardwired onboard in embedded motherboards (is Russell King the father of Linux on ARM ?), rather than general-purpose PnP and addon boards. I'd love to use existing code of the phylib to talk to the SFP PHY's, maybe extend the phylib a bit (with the phy's I have), rather than cobble together something crude and private on my own, inside the igb driver. If you have any pointers, let me know. Frank
